Compounds doi: 10.3390/compounds6020029

Authors: Martha Salinas-Sandoval Gildardo Rivera Luis Fernando Ceja-Torres Martha-Isabel González-Domínguez Alma D. Paz-González Janneth López-Mercado Dioselina Álvarez-Bernal

The potential of methanolic extracts from jara (Barkleyanthus salicifolius) and pomegranate carpel membranes (Punica granatum) as biological alternatives for the control of phytopathogenic fungi was evaluated against pathogens associated with commercially important crops in the Ciénega de Chapala region. Extracts were assessed in vitro against Botrytis cinerea and Rhizoctonia solani (strawberry), Curvularia sp., Pestalotiopsis sp., and Fusarium oxysporum (blackberry), Pythium sp. and Fusarium sp. (tomato), and Sclerotium rolfsii (onion). Antifungal bioassays demonstrated that the B. salicifolius extract inhibited the mycelial growth of R. solani, whereas the pomegranate extract inhibited seven of the eight species tested, with the exception of S. rolfsii. Phytochemical screening revealed the presence of alkaloids, flavones, flavonols, chalcones, and quinones in pomegranate, and flavones, flavonols, alkaloids, and sterols in jara. Additionally, phytol and caryophyllene were identified in the latter via GC–MS.

Compounds doi: 10.3390/compounds6020028

Authors: Stefano Dossi Pietro Matteucci Andrea Galanti Flavia Bartoli Sabrina Bianchi Francesco Ciardelli

For cable compound manufacturers, accurate formulation fine-tuning is essential to ensure safety, long-term durability, and compliance with international standards for dielectric strength, volume resistivity, and environmental and thermal ageing. This work presents an experimental study demonstrating how minor additives can critically affect the performance of complex flame-retardant elastomeric formulations. The investigation focuses on the role of small amounts of zinc oxide (ZnO) in commercial cable compounds based on a crosslinked elastomeric matrix composed of ethylene–propylene monomer (EPM), ethylene–propylene–diene monomer (EPDM), and thermoplastic polyolefin elastomer (POE). The formulations contain aluminium trihydroxide (ATH) as the major filler, together with several minor additives. Among these, a phenolic antioxidant (AN01) acting as a metal deactivator is also present. The addition of ZnO in low amounts (2–5 phr) allowed the compounds to maintain a volume resistivity ≥ 1012 Ω·cm in water at 100 °C. To elucidate the role of ZnO, a systematic set of formulations was prepared by varying the type and content of selected additives. The compounds were prepared by melt mixing in an internal mixer (Banbury type), followed by peroxide crosslinking via compression molding. Electrical characterization results indicate that ZnO interacts with the phenolic additive through surface adsorption, forming a coated particle with significantly reduced electrical conductivity. Optimal electrical performance was achieved when the ZnO-to-additive ratio corresponded to the minimum amount required for complete surface complexation.

Compounds doi: 10.3390/compounds6020027

Authors: Hernán Vera-Benavides Dayana Quinchanegua Antonia Osorio-Weng Yihajara Fuentes Paulina Pavez Gloria Montenegro Patricia Velásquez Ady Giordano

Nalca (Gunnera tinctoria Mol.) is traditionally consumed for its edible petioles and valued for medicinal properties associated with its bioactive compounds. In this study, natural deep eutectic solvents (NADESs) were synthesized and applied for the ultrasound-assisted extraction of phenolic compounds and alkaloids from Nalca leaves. NADES synthesis was confirmed using 1H NMR, and their physicochemical properties were evaluated to assess their influence on extraction efficiency. The extracts showed total phenolic contents ranging from 6.8 to 142.6 mg GAE/g DW and total alkaloid contents ranging from 0.2 to 3.2 mg OXIE/g DW, depending on solvent composition. Antioxidant activity, evaluated using DPPH and FRAP assays, confirmed that most NADES extracts exhibited significant radical-scavenging and ferric-reducing capacities, generally correlating with phenolic content. The extraction yields obtained with specific NADES formulations were comparable or superior to those achieved with conventional solvents, demonstrating their efficiency. These results demonstrate that NADESs are effective and environmentally friendly alternatives to conventional solvents for extracting bioactive compounds from Nalca leaves. The physicochemical properties of NADESs enable the selective extraction of different metabolite classes, highlighting their potential for green extraction processes in food, nutraceutical, and pharmaceutical applications.

Compounds doi: 10.3390/compounds6020026

Authors: Alfredo Varela-Esquer Saul Ruíz-Cruz María Isabel Estrada-Alvarado Martin Valenzuela Melendres Luis A. Cira-Chávez Enrique Márquez-Ríos José de Jesús Ornelas-Paz Carmen Lizette Del-Toro-Sánchez Víctor Manuel Ocaño-Higuera

The growing demand for healthier meat products has led to efforts to reduce synthetic additives, such as nitrites, in processed meats. This study evaluated the effect of enriched safflower oil with oleoresin from Capsicum annuum var. Anaheim (ESO) as a functional ingredient in the reformulation of Frankfurt-style pork sausages with reduced nitrite content. Five formulations were evaluated: a negative control without additives (F1 (0% ESO, 0% nitrite), a positive control containing only sodium nitrite F2 (0% ESO, 0.15% nitrite = 93.8 mg/kg), and three experimental treatments contained ESO and nitrite: F3 (0.5% ESO, 0.075% nitrite = 46.9 mg/kg), F4 (1% ESO, 0.05% nitrite = 31.3 mg/kg), and F5 (1.5% ESO, 0% nitrite), stored under refrigeration (4 °C) for five weeks. Physicochemical (pH, color, texture profile, proximate composition, residual chlorides and nitrites), oxidative (TBARS), and microbiological (total viable count) analyses were conducted over 5 weeks of storage. Results showed that formulation F4 provided the best balance between oxidative stability microbial control and nitrite residual content, maintaining TBARS levels below the 1.0 mg MDA/kg rancidity threshold (0.33 ± 0.01 mg MDA/kg), TVC within the 6.0 log CFU/g limit for processed meats (3.89 log CFU/g) and 1.15 mg/kg of nitrite residual at the end of the storage period. These findings suggest a synergistic effect between ESO and nitrites. Since addition of ESO was consistent with improved cured color development, likely due to the combined effect of reduced nitrite levels and the natural pigments from Anaheim chili. These findings demonstrate that ESO is a promising natural additive to partially replace nitrites, contributing to the development of healthier and safer processed meat alternatives.

Compounds doi: 10.3390/compounds6020025

Authors: Francisco Jonathan Pérez-Delgado J. Abraham Domínguez-Avila Gustavo A. González-Aguilar Jesús Fernando Ayala-Zavala Mónica A. Villegas-Ochoa Alejandro Martínez-Martínez Alejandra M. Preciado-Saldaña Denisse García-Villa Marcelino Montiel-Herrera

Antioxidants, such as phenolic compounds, are essential for mammal physiology. Significant research made on the gut–brain axis has produced volumes of evidence indicating that some plant-derived phenolic compounds can reach brain cells to exert protective effects on them, mainly by maintaining and/or restoring redox homeostasis. Their systemic uptake and transport might be determined by the phenolic’s physicochemical properties, along with complex interactions with protein transporters and carriers, including GLUT, SGLT1, ABC transporters (P-glycoprotein, breast cancer resistance protein), albumin, fibrinogen, organic anion and cation transporters, and MATE1. The present work focuses on the chemical interactions and transport pathways of some phenolic compounds to reach brain cells.

Compounds doi: 10.3390/compounds6010024

Authors: Noriyuki Suzuki Muneyasu Hara Yuxuan Gao Yumiko Suzuki

A novel multidentate ligand with an O,N,O-tridentate ligand moiety and an N-heterocyclic carbene (NHC) was synthesized. Its palladium complex, in which the NHC part coordinates to the palladium atom, was synthesized and structurally characterized. The O,N,O-part coordinated to an early transition metal such as titanium. The Ti-Pd heterobimetallic complex was observed in solution.

Compounds doi: 10.3390/compounds6010023

Authors: Somrita Mondal Leslie Garcia Allison L. Bond Maecy L. Spencer Grant T. Elam Yuki Matsui Alex Thao Timothy J. Hubin

Mn and Fe complexes of ethylene cross-bridged tetraazamacrocycles, known to retain their reactive metal ions even under harsh aqueous conditions due to the rigidity and topological constraint of the ligands, with methyl, allyl and benzyl pendant arms were electrostatically fixed to a commercial cation exchange resin, and their effectiveness and recyclability in the bleaching of organic dyes, namely, methyl orange, methylene blue and rhodamine B, were determined. These molecular Mn and Fe tetraazamacrocycle catalysts have been previously reported as homogeneous solution phase catalysts for bleaching organic dyes, but could not be feasibly recovered for multiple cycles of dye bleaching. Herein, we report the potential of these resin-fixed solid-state metal complex catalysts in the degradation of organic dyes. The Mn catalysts were faster in the first cycle of dye bleaching, but their bleaching rate slowed considerably (to about 10% on average) in additional cycles. In contrast, the Fe catalysts were slower in the first cycle of dye bleaching, but were able to bleach dyes for up to five cycles while retaining more of their original reactivity (30–50% on average), suggesting their potential recyclability. Thus, these resin-fixed tetraazamacrocyclic metal complex catalysts, when coupled with the demonstrated rechargeability of the resin with fresh catalyst, may one day be effectively used for water purification applications. SEM and optical microscopy images demonstrated the robustness of the resin bead across multiple cycles, while EDS experiments confirmed the continued presence of Mn and Fe on the bead surface after multiple cycles.

Compounds doi: 10.3390/compounds6010022

Authors: Tatjana Vukotić Milica Nemoda Vladimir Živanović Filip Veljković Božana Petrović Marijana Janić Jelena Filipović Tričković Biljana Nikolić Jelena Marinković

Background: Increasing antimicrobial resistance has directed studies toward investigating the antimicrobial activity of thymol, as well as the antibiofilm and antioxidant potential of its emulsions (with Tween 80) against multidrug-resistant (MDR) K. pneumoniae isolates. Methods: A microdilution assay was used to estimate thymol’s antibacterial potential against 10 clinical isolates (labeled 1–10). The dynamic light scattering technique was used to measure the particle size diameter (Zavg) of formulated emulsions. The antibiofilm potential of emulsions was assessed in vitro using a crystal violet assay and ex vivo on a surgical drain through a colony-forming unit assay. Antioxidant activity was screened by using the DPPH assay. Results: The MIC values were ≤1.5 mg/mL for strains 1 and 7 and <0.5 mg/mL for the other strains. Emulsions E250:500, E250:750, E300:750, and E500:750 were stable and homogeneous, with a Zavg of approx. 200 nm (128.4 ± 0.8 nm for E250:750). These emulsions significantly reduced the biofilm biomass of strains 3 and 7 (50.6–74.32% and 34.60–59.8% of inhibition, respectively), with the strongest activity observed for E250:500 and E500:750. Antibiofilm potential was confirmed ex vivo, with E500:750 showing the highest efficacy (ΔLogCFU 2.60 and 2.68 for strains 3 and 7). E250:750 demonstrated the highest capacity to neutralize the DPPH• radical. Conclusions: Thymol and its emulsions exhibited antibacterial and antibiofilm activity against MDR K. pneumoniae isolates, along with the proven antioxidant properties of the emulsions.

Compounds doi: 10.3390/compounds6010021

Authors: Assaad Elouafi Abdeslam Tizliouine

α-Fe2−4xZ3xO3 (Z = Ce, Ru) nanoparticles were synthesized via a conventional solid-state reaction route. X-Ray diffraction analysis confirmed that all compositions crystallize in the single-phase hexagonal hematite (α-Fe2O3) structure, with no detectable secondary phases. Cerium substitution resulted in a pronounced reduction in crystallite size accompanied by a progressive narrowing of the optical band gap, which decreased to approximately 1.73 eV at higher Ce contents. The optical properties were further investigated through absorption coefficient, optical transmittance, and complex refractive index analyses, revealing that cerium-doped hematite exhibits enhanced light-harvesting capability, highlighting its strong potential for optoelectronic and solar-energy conversion applications. Magnetic hysteresis measurements on α-Fe2−4xRu3xO3 samples showed a systematic increase in both coercive field (Hc) and remanent magnetization (Mr) with increasing Ru concentration. This magnetic hardening behavior is attributed to strengthened magnetocrystalline and shape anisotropy induced by Ru incorporation into the hematite lattice. Mössbauer spectroscopy confirmed the presence of Fe3+ and Ru4+ species, providing valuable insight into the oxidation states and local magnetic environments within the corundum-type structure.

Compounds doi: 10.3390/compounds6010020

Authors: Ezra E. Cable Keith Bratley Ryan Buzzetto-More Bokary Sylla Sara Lahoff William L. Weaver Victoria V. Volkis

Biofouling, the formation of a biofilm on submerged surfaces, is a widespread problem affecting all of the maritime industries and ecosystems. Historically, antifouling solutions have included toxic compounds, such as heavy metals and tributyl tin. Recently, less-toxic antifouling paints have been explored, including paints made from antioxidant-rich plants, and a study measured the effectiveness of polymer blends containing Aronia mitschurinii extracts. This new study will compare those results with polymer blends made from extracts of juvenile ginger and holy basil, two plants rich in antioxidants and essential oils. Extracts were assessed for antioxidant and essential oil content. Then, slides coated with a polymer-extract blend were exposed to freshwater and saltwater for three weeks and assessed by contrast microscopy. For freshwater and saltwater analysis, holy basil extracts had a minimum precipitation count of 3.40 ± 0.4 and 22.4 ± 6.0 for non-stained slides and 58.3 ± 7.3 and 9.3 ± 1.0 for stained. Ginger extracts had a minimum precipitation count of 3.9 ± 0.8 and 87.1 ± 17.3 for non-stained slides, and 5.4 ± 1.8 and 9.5 ± 0.3 for stained slides. All minimum precipitation counts for ginger and holy basil were less than those measured by controls and Aronia mitschurinii, showcasing the antifouling potential of ginger and holy basil extracts at a compatible but slightly lower level, but one that is much higher than was reported for other plant materials.

Compounds doi: 10.3390/compounds6010019

Authors: Mirana Rakotozafy Rivoarison Randrianasolo Solomon Tesfaye Christian Schulze Dimby Andrianina Ralambomanana Patrick J. Bednarski Sharif Mortoga Andreas Link

In recent years, Biophytum umbraculum Welw. (Oxalidaceae) has undergone several phytochemical and pharmacological investigations. Although its major phytochemical classes have been characterized, few isolated compounds have been reported. The previously detected phytoconstituents, along with the documented antioxidant and anti-inflammatory activities, both align with a potential antiproliferative effect. This study aims to complement the existing chemotaxonomic profile of B. umbraculum through the isolation and identification of phytoconstituents and to evaluate the antiproliferative potential of its extracts. Hexane, ethyl acetate, and methanolic extracts of B. umbraculum were screened against two human adherent cell lines, breast (MCF-7) and cervical (SiSo) adenocarcinomas, by using the crystal violet staining assay. The hexane extract inhibited both MCF-7 and SiSo cell proliferation with IC50 values of 8.93 ± 0.07 and 14.59 ± 0.08 µg/mL, respectively. The ethyl acetate extract showed activity against both cell lines, with IC50 values of 12.60 ± 0.14 and 13.10 ± 0.04 µg/mL, respectively. However, the methanolic extract was inactive on the MCF-7 cell line and only slightly active on the SiSo cell line. Chromatographic fractionations led to the isolation of ursolic acid from the active ethyl acetate extract and rutin from the methanolic extract. A further antiproliferative evaluation is warranted to confirm the contribution of ursolic acid to the effect of the ethyl acetate extract. Additional fractionations may uncover more phytoconstituents of diverse pharmaceutical interests.

Compounds doi: 10.3390/compounds6010018

Authors: Marek Gliński Adrian Dąbrowski Agata Kacprzak Ewa M. Iwanek (nee Wilczkowska) Jan Borucki

A systematic study of the chemoselectivity of the reduction of 3-methylcyclohex-2-enone (seudenone) to 3-methylcyclohex-2-enol (seudenol) was performed. Two approaches were investigated, namely the reduction of this ketone using NaBH4 with modifiers and Catalytic Transfer Hydrogenation (CTH). The former resulted in higher conversions (95–99%) and high selectivity (up to 95%), whereas with CTH, a selectivity of 100% was achieved, albeit with a low conversion. The study therefore demonstrated that it is possible to chemoselectively reduce an α,β-unsaturated ketone in the liquid phase CTH using MgO as the catalyst and 2-pentanol as the hydrogen donor. The application of modifiers such as CeCl3 · 7H2O and MCl2, where M = Be, Mg, Ca, Sr, and Ba, resulted in a significant improvement of the chemoselectivity (up to 95%) of the reduction with NaBH4. The effect of parameters such as the solvent mixture composition, reaction temperature and modifier:NaBH4 molar ratio was also investigated. In CTH, although high conversions of the ketone were observed for Al2O3, ZrO2 and MgO in the vapor phase, the first two did not yield 3-methylcyclohex-2-enol among the obtained products. It was shown that 3-methylcyclohex-3-enol was the main product of the transformations of 3-methylcyclohex-2-enone in the presence of MgO, with yields of 25–33%. In a series of experiments, it was shown that 3-methylcyclohex-3-enol is formed as a result of the transformation of 3-methylcyclohex-2-enol in the presence of MgO as a catalyst.

Compounds doi: 10.3390/compounds6010017

Authors: Rhonyele Maciel da Silva Rita Sannara Bandeira do Nascimento Fabiano André Narciso Fernandes Thaiz Batista Azevedo Rangel Miguel Emilio de Castro Miguel Pedro Henrique Campelo Glácio Souza Araújo Sueli Rodrigues

The growing demand for sustainable, functional food ingredients has increased interest in algae, particularly for their bioactive compounds. Gracilaria birdiae is mainly used for agar production, but its protein potential is underexplored. Conventional extraction methods require high temperatures and long durations, whereas emerging technologies, such as ultrasound (US), could be more efficient alternatives when combined with other strategies. This study is the first to evaluate the co-extraction of carbohydrates and proteins from G. birdiae using US combined with different extraction methods. The proximate composition of the algae was as follows: 63.97% carbohydrates, 5.20% proteins, and 19.65% lipids. Ethanol pretreatment did not improve US co-extraction but enabled phycobiliprotein recovery. Higher US power (500 W, 373 W·cm−2) and biomass concentration enhanced recovery, achieving up to 64.43 mg/g of carbohydrates and 10.28 mg/g of proteins. Sequential extraction using hot water and US at 60 °C produced 97.51 and 74.70 mg/g of carbohydrates and 5.67 and 5.08 mg/g of proteins, respectively. Acid treatment combined with US 60 °C achieved the highest recovery of 396.15 mg/g carbohydrate (1% v/v H2SO4) and 38.49 mg/g of protein (7% v/v H2SO4). Alkali extraction yielded lower amounts: 190.51 mg/g of carbohydrates and 33.20 mg/g of protein using 5% w/v NaOH. Microscopy revealed that the chemical treatments fully disrupted the cell wall, promoting compound release. Thus, combining the US with chemical extraction effectively enhances carbohydrates and protein recovery from G. birdiae.

Compounds doi: 10.3390/compounds6010016

Authors: Norma Mallegni Niccoletta Barbani Silvia Tampucci Chiara Salvini Miriam Cappello Serena Coiai Elisa Passaglia Caterina Cristallini

In this work, gellan gum microspheres (G–MPs) were developed as delivery systems for blueberry extract (Vaccinium myrtillus) (BEX), a source of natural antioxidants rich in anthocyanins (ATCs) and phenolic compounds (PHCs). Gellan gum, an anionic polysaccharide produced via fermentation by Sphingomonas elodea, was selected for its biocompatibility and gelling properties. BEX was obtained using a mild citric acid–based extraction method to preserve antioxidant capacity and was characterized for its total polyphenol, flavonoid, and anthocyanin content before loading. The extract was loaded into gellan gum microspheres via absorption (G–MPs–BEX). The resulting microspheres exhibited a spherical and porous morphology that favoured both encapsulation and controlled release. FT–IR analysis confirmed the absorption of the extract within the polymer network and revealed hydrogen bonding interactions between the matrix and active compounds. Despite these interactions, microspheres retained a high swelling capacity and enabled rapid release, with maximum release of polyphenols and anthocyanins within 30 min at pH 5.5. The antioxidant activity of BEX, assessed via DPPH assay, remained stable during storage (up to 60 days) and after incorporation into the microspheres. Overall, this study demonstrates that G–MPs can efficiently absorb, stabilize, and release natural antioxidant compounds, supporting their potential use in biomedical, nutraceutical, and cosmetic applications.

Compounds doi: 10.3390/compounds6010015

Authors: Letícia Pena Botelho Daniele Morais Dias Karine Taís Aguiar Tavano Adriana da Silva Torres Moisés de Matos Torres Larissa Doalla Almeida e Silva Renan Leonardi de Oliveira Rigotti Rodrigo Galo

This study evaluated the effects of incorporating silk fibroin nanoparticles into self-curing polymethyl methacrylate (PMMA) on the mechanical and Candida albicans responses of provisional dental prostheses. Rectangular specimens (64 × 10 × 3 mm) were fabricated and assigned to three groups (n = 10): G1 (control), PMMA without reinforcement; G2, PMMA with 0.5% silk nanoparticles; and G3, PMMA with 1% silk nanoparticleScheme4. 4 × 6 mm) were prepared. Scanning electron microscopy (SEM) was used to assess nanoparticle incorporation within the polymer matrix. No significant differences were observed in surface roughness (G1 = 0.4118 ± 0.100; G2 = 0.3245 ± 0.072; G3 = 0.3269 ± 0.076) or microhardness (G1 = 12.21 ± 0.351; G2 = 12.72 ± 0.213; G3 = 12.53 ± 0.177). Flexural strength differed significantly among the groups (p = 0.009), with higher values in nanoparticle-reinforced specimens (G1 = 79.142 ± 3.202; G2 = 87.089 ± 2.756; G3 = 92.412 ± 1.963). None of the tested concentrations exhibited antifungal activity against C. albicans. In conclusion, the incorporation of silk fibroin nanoparticles enhanced the flexural strength of self-curing PMMA without adversely affecting surface roughness or microhardness, although no antifungal effect was detected at the evaluated concentrations.

Compounds doi: 10.3390/compounds6010014

Authors: Anna Hawrył Mirosław Hawrył Mykhaylo Chernetskyy Wiktor Wojciech Winiarski Anna Oniszczuk

The aim of this study was to evaluate, on a preliminary basis, the ability of multivariate techniques to predict the antioxidant activity of selected Stachys and Betonica species, based on chromatographic data. The methanol extracts of six Stachys species and ten Betonica species were analyzed using reversed-phase high-performance liquid chromatography (RP-HPLC) to obtain their chromatographic profiles. The phytochemical similarity of the samples was assessed using a selected chemometric method (principal component analysis (PCA) and hierarchical cluster analysis (HCA)). The antioxidant activity of the studied extracts (DPPH with 2,2-diphenyl-1-picrylhydrazyl reagent and FRAP—ferric reducing antioxidant power) was determined using a spectrophotometric technique. A multivariate PLS model was then used to predict the antioxidant activity of the methanolic extracts of Stachys and Betonica species based on their RP-HPLC fingerprints. The two obtained PLS models proved useful for predicting the biological activity of the tested extracts. High correlation coefficients (DPPH: R2 = 0.9963; FRAP: R2 = 0.9895) confirmed the reliability of the PLS prediction model. The results confirmed the effectiveness of combining qualitative and quantitative chromatographic fingerprinting methods with antioxidant activity testing and chemometric analysis, demonstrating that extracts from Stachys and Betonica are a rich source of bioactive substances with antioxidant properties.

Compounds doi: 10.3390/compounds6010012

Authors: Irina V. Palamarchuk Aida S. Rakhimzhanova Svetlana S. Volkova Alexander S. Novikov Irina A. Pustolaikina Ivan V. Kulakov

Terpyridines are well-known ligands in coordination chemistry, are valued for their conformational flexibility and strong metal-binding properties, and are also of interest as fluorophores. This study focused on the synthesis and comprehensive investigation of a new class of bis-oxazolo[5,4-b]pyridine derivatives, designed based on their structural similarity to terpyridines. Four novel compounds, 4a–d, were synthesized by cyclization of amide derivatives of 3-aminopyridin-2(1H)-ones using pyridine-2,6-dicarboxylic acid and its dichloride as key acidic components. Their structures and purity were confirmed by melting point analysis, high-resolution mass spectrometry, and 1H, 13C NMR spectroscopy. Compounds 4a–c exhibit UV absorption at 323–357 nm and intense blue to deep-blue fluorescence (357–474 nm, цi ≈ 0.32–0.84) in chloroform, dichloromethane, and acetonitrile, attributed to p–p* transitions within the conjugated ring system. These findings suggest their potential as phosphors for organic electronics. Computational modeling of 4a–c molecules provided insight into their electronic structures, conformational stability, and predicted optical behavior. The most stable conformers (4a–II, 4b–II, 4c–II′) exhibited a progressive decrease in the HOMO–LUMO gap from 4a to 4c, correlated with the enhancement of photoactivity. Among them, compound 4a stands out as the most promising luminophore, displaying the most intense and narrow luminescence band, owing to its high molecular symmetry and stable emission characteristics. Overall, this study lays the foundation for future studies of bis(oxazolo[5,4-b]pyridine) derivatives in coordination chemistry and optoelectronic materials development.

Compounds doi: 10.3390/compounds6010011

Authors: Paul D. Entzminger Edward J. Valente Eugenijus Urnezius

Two crystalline complexes, (2,2′-bipyridine)Cu(CH3COO)2·5H2O (3) and (2,2′-bipyridine)Cu(CH3COO)2·CH3CN (4), have been isolated and characterized by low-temperature single-crystal X-ray diffraction experiments. Crystals of phase 3 were studied previously at room temperature (296 K) under conditions leading to rapid desolvation and less distinct characterization of the waters of crystallization. With our redetermination of 3 at 100(2) K, we present a detailed description of ribbon-like structure formed by water molecules in crystals of (2,2′-bipyridine)Cu(CH3COO)2·5H2O. Acetate oxygens are linked by hydrogen-bonding to two inequivalent waters separated by 4.72 Å; the other three water molecules are trapped in polymeric ribbons of anticooperative hydrogen-bonded six-membered rings fused with cooperative hydrogen-bonded four-rings. Water oxygens of the fused ring ribbons associate only with other water oxygens, and this water structure has a local density and pair distribution function which resembles that of liquid water. Crystals of 4 are monoclinic, with acetonitrile of solvation unassociated with the complex. In both 3 and 4, bipyridine planes interleave through π-aryl stacking.

Compounds doi: 10.3390/compounds6010013

Authors: Kostas Ioannidis Nikoleta Soulioti Polyxeni Koropouli Eleni Melliou Prokopios Magiatis Georgios Menexes

The natural durability of wood, determined primarily by its chemistry, meets the growing demand for environmentally sustainable alternatives to toxic wood preservatives. This study assessed the relationship between the fungitoxic acetone extractive content, in particular resin acids and stilbenes, and heartwood decay resistance among fifty-two Pinus nigra J. F. Arnold clones from a clonal seed orchard in Greece. Quantitative 1H-NMR spectroscopy was employed to determine total stilbenes (TSs) and total resin acids (TRAs) in heartwood samples, while decay resistance was evaluated through standardized weight loss tests using the brown-rot fungus Coniophora puteana (Schumach.) P. Karst. (1865) and the white-rot fungus Porodaedalea pini (Brot.) Murrill (1905). The heartwood exhibited exceptionally high extractive content (mean TAE = 304.15 mg gdhw−1), with resin acids (68.26%) predominating over stilbenes (22.31%). Regression analysis showed that the TAE and TRAs were the strongest predictors of decay resistance, explaining 33% of the variance, while stilbenes exhibited weaker and more variable associations. P. pini caused significantly higher mean weight loss (11.43%) than C. puteana (3.55%), indicating species-specific fungal aggressiveness. Among individual resin acids, abietic acids were the most influential contributors to decay resistance. The results demonstrate that resin acids have a dominant role over stilbenes in determining the natural durability of P. nigra (Black pine) heartwood and could serve as effective biochemical markers for selective breeding.

Compounds doi: 10.3390/compounds6010010

Authors: Eloy Rodríguez-deLeón José E. Báez Guadalupe García-Alcocer Fabián Santa-María Miguel A. Ramos-López Claudia Gutiérrez-García Moustapha Bah

Propolis is a resinous material produced by honeybees characterized by a high phenolic compound and flavonoid content. To date, several studies have examined the chemical composition of Mexican propolis from the south and north of the country. However, limited information is available on the chemical profile of propolis from central Mexico. The present study isolated six known compounds from propolis from central Mexico: one diterpene (sugiol, found for the first time in Mexican propolis), three flavonoids (chrysin, galangin 3-methyl ether, and 3,7-dimethoxyquercetin), a fatty acid (cerotic acid), and an unusual glycerol derivative (batyl alcohol). Moreover, LC-ESI-MS analysis conducted on the ethanolic extract led to the identification of three phenolic compounds and fourteen flavonoids commonly found in propolis. Lastly, the cytotoxic activity evaluation carried out on the ethanolic extract showed a decrease in the cell viability of human leukemia (Jurkat) cells in a concentration-dependent manner.

Compounds doi: 10.3390/compounds6010009

Authors: Jung-Bum Lee Kyoko Hayashi

The discovery of antiviral agents is an important research area because the world is increasingly exposed to the risk of viral infectious diseases. Herpes simplex virus type 2 (HSV-2) causes globally prevalent sexually transmitted diseases, and numerous individuals are living with HSV-2. Influenza A virus (IAV) causes annual epidemics and occasional pandemics, attracting great concern in public health. In this study, antiviral activities against HSV-2 and IAV of 103 flavonoids were screened. The screening identified cirsilineol and apigenin as active against HSV-2, while cirsimaritin and hymenoxin displayed anti-IAV activity. These flavonoids have the potential to serve as therapeutic candidates for viral infectious diseases.

Compounds doi: 10.3390/compounds6010008

Authors: Noureddine Djebli Nadjet Mostefa Hadjer Chenini-Bendiab Mokhtaria Hamidi Arbia Zitouni Flávia dos Santos Ferreira Graziele Freitas de Bem

Background: The incidence of dementia, especially Alzheimer’s disease (AD), is rising, with over 55 million affected globally. Therefore, this disease, for which there is no adequate treatment, is more frequent and prevalent in women. Royal jelly, a bee secretion, is known for its health benefits and contains proteins, carbohydrates, lipids, minerals, polyphenols, enzymes, and B vitamins, as well as anti-inflammatory and antioxidant properties relevant to AD. Thus, we aimed to investigate the chemical compounds in royal jelly extract and their effect on neurobehavioral changes in an AD female model. Methods: In vitro studies were used to investigate the chemical and physicochemical properties of the royal jelly extract. In vivo studies, we divided female mice into five groups (n = 25): Control (C), Alzheimer (ALZ), ALZ standard (ALZ-STD, rivastigmine 1 mg/Kg), ALZ-D1 (royal jelly 150 mg/kg), and ALZ-D2 (royal jelly 300 mg/kg). The mice received the treatments orally at 45 days. We induced the AD model by orally administering aluminum chloride at 100 mg/kg and intraperitoneally injecting D-galactose at 120 mg/kg for 45 consecutive days, after which we subjected the animals to the radial arm maze, Morris water maze, elevated plus maze, and forced swim tests. Results: Analyses showed moderate acidity and a rich bioactive profile, with flavonoids being more prevalent. Antioxidant activity tests indicated moderate efficacy, while FTIR-ATR analysis revealed the chemical complexity of royal jelly. The royal jelly extract used in the study did not induce toxicity in vivo. Notably, royal jelly improved cognitive deficits, neurodegeneration, and reduced anxiety in AD. Conclusions: The study suggests that royal jelly extract has promising neuroprotective properties and could be a viable natural therapeutic option for AD.

Compounds doi: 10.3390/compounds6010007

Authors: Valery M. Dembitsky Alexander O. Terent’ev

Endoperoxides constitute a distinctive class of highly oxygenated terpenoids defined by the presence of a cyclic peroxide (–O–O–) bond, a structural motif responsible for their pronounced chemical reactivity and diverse biological effects. Naturally occurring endoperoxide-containing terpenoids are broadly distributed across terrestrial and marine taxa, including higher plants, algae, fungi, and bryophytes, where they are believed to participate in chemical defense and ecological interactions. This review provides a comprehensive overview of naturally occurring endoperoxide terpenoids, focusing on their natural sources, structural diversity, and reported biological activities. Particular emphasis is placed on compounds exhibiting antiprotozoal and antitumor activities, exemplified by artemisinin and its derivatives, which remain cornerstone agents in antimalarial therapy and continue to attract interest for their anticancer potential. Structure–activity relationship (SAR) analysis, supported by computational prediction using the PASS (Prediction of Activity Spectra for Substances) platform, is employed to examine correlations between peroxide-containing frameworks and biological function. Comparative assessment of experimental data and predicted activity profiles identifies key structural features associated with antiprotozoal, antineoplastic, and anti-inflammatory effects. Collectively, this review highlights endoperoxides as a valuable and chemically distinctive class of bioactive natural products and discusses their promise and limitations as leads for further pharmacological development, particularly in light of their intrinsic reactivity and stability challenges.

Compounds doi: 10.3390/compounds6010006

Authors: Thi-Hai Anh Nguyen Tran Van Tam Minh-Tri Nguyen-Le

This study investigates the activation mechanism of boron-doped carbon (BMC) catalysts for the degradation of the antibiotic sulfamethoxazole (SMX) via persulfate (PMS) activation. The catalysts were synthesized using a sequential double-melting calcination method, resulting in mesoporous carbon nanosheets characterized by hierarchical macro-mesopores and atomically dispersed dual active sites. Comprehensive characterization was performed using BET, SEM, TEM, FT-IR, XPS, XRD, and Raman techniques. The optimized BMC catalyst demonstrated excellent performance, achieving complete removal of sulfamethoxazole (100%) and a high mineralization rate (~90%) within 45 min. Mechanistic analysis, including electron paramagnetic resonance (EPR), revealed that the degradation predominantly follows a singlet oxygen (1O2)-dominated pathway. The system exhibited broad applicability to various pollutants, along with notable operational stability and robust resistance to common environmental interferents. Persulfate activation was primarily attributed to boron-active sites, while the hierarchical mesoporous structure facilitated both pollutant enrichment and catalytic efficiency.

Compounds doi: 10.3390/compounds6010005

Authors: Tomoko Ito Yoshiyuki Koyama

Poly(acrylic acid)/polyvinylpyrrolidone (PAA/PVP) hydrogen-bonded complexes are of growing interest as functional materials for biomedical applications. However, the influence of polyhydroxyl additives, such as polyols and sugars, on complex formation and material performance remains insufficiently understood. This study aimed to elucidate how polyhydroxyl compounds affect the physical properties of PAA/PVP complexes. Dried PAA films were brought into contact with aqueous PVP solutions containing various additives (glycerol, sugar alcohols, or sugars), and the resulting hydrogels were dried to form films. Their swelling behavior in water and PBS, thermal stability, and mechanical properties were comparatively evaluated. Sugar alcohols markedly improved swelling and flexibility, whereas sugars showed limited effects. Glucitol exhibited intermediate performance due to a high tendency toward intramolecular hydrogen bonding in aqueous media. Mechanistic analysis suggested that sugar alcohols act in a chaperone-like manner during complex formation, promoting microphase-separated structures composed of hydrogen-bonded domains and free segment regions. These findings provide new molecular insight into designing PAA/PVP-based materials with additives for biomedical applications.

Compounds doi: 10.3390/compounds6010004

Authors: Marcos Edgar Herkenhoff Oliver Brödel Guilherme Dilarri Miklos Maximiliano Bajay Marcus Frohme Carlos André da Veiga Lima Rosa Costamilan

Humulus lupulus L. (hops) is essential in brewing due to its contributions to bitterness, flavor, and aroma. This study compared the volatile profiles of five commercially important hop varieties—Amarillo, Ariana, Cascade, Centennial, and El Dorado—grown in their main regions of origin (United States for Amarillo, Cascade, and El Dorado; Germany for Ariana; and Brazil for Centennial). Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS) enabled the identification of 312 volatile compounds, including monoterpenes (e.g., myrcene, linalool, geraniol), sesquiterpenes (e.g., humulene, caryophyllene), esters, alcohols, aldehydes, and ketones. Amarillo showed the highest myrcene content (22.61% of the total volatile area), while Centennial was distinguished by elevated γ-muurolene (20.59%), and El Dorado by the highest level of undecan-2-one (10.47%), highlighting marked varietal differences in key aroma-active constituents. Multivariate, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), clearly discriminated the five varieties: PC1 (41.04% of the variance) separated samples enriched in fruity/floral monoterpenes and esters from those dominated by woody/resinous sesquiterpenes, whereas PC2 (25.93% of the variance) reflected variation in medium-chain esters, ketones, and waxy compounds. These chemometric patterns demonstrate that both genetic background and growing region terroir strongly shape hop volatile composition and, consequently, aroma potential, providing brewers with objective criteria for selecting hop varieties to achieve specific sensory profiles in beer.

Compounds doi: 10.3390/compounds6010003

Authors: Maria Federica De Riccardis Carmela Tania Prontera

Electrospinning has emerged as a powerful technique for fabricating customised nanofibrous materials with integrated functional nanostructures, offering significant advantages for electrochemical energy applications. This review highlights recent advances in using electrospun nanofibres directly as active components in devices such as batteries, supercapacitors, and fuel cells. The emphasis is on the role of composite design, fibre morphology and surface chemistry in enhancing charge transport, catalytic activity and structural stability. Integrating carbon-based frameworks, conductive polymers, and inorganic nanostructures into electrospun matrices enables multifunctional behaviour and improves device performance. The resulting nanofibrous composite materials, often after heat treatment, can be used directly as electrodes or self-supporting layers, eliminating the need for additional processing steps such as size reduction or preparation of slurries and inks for creating functional nanofibre-based deposits. The importance of composite nanofibres as an emerging strategy for overcoming challenges related to scalability, long-term durability, and interface optimisation is also discussed. This review summarises the key results obtained to date and highlights the potential of electrospun nanofibres as scalable, high-performance materials for next-generation energy technologies, outlining future directions for their rational design and integration.

Compounds doi: 10.3390/compounds6010002

Authors: José Jailson Lima Bezerra Antonio Fernando Morais de Oliveira

Gastrointestinal disorders negatively affect populations worldwide. Considering the side effects of synthetic drugs, natural products can be a safe and effective alternative to help treat gastric ulcers and diarrhea. In this context, the present study reviewed the antiulcerogenic and antidiarrheal activities of species of the genus Croton (Euphorbiaceae). The scientific documents were retrieved from different databases, covering publications from the first report on the topic in 1998 to October 2025. Although the genus Croton comprises approximately 1200 species, only 11 have been evaluated for their antiulcerogenic and antidiarrheal potential in in vivo and in vitro studies. Among the identified bioactive constituents, the diterpenes trans-dehydrocrotonin and trans-crotonin, isolated from Croton cajucara, demonstrated significant antiulcerogenic activity in several experimental models in vivo. Similarly, the compound crofelemer, isolated from the latex of the bark of Croton lechleri, has shown promising results in several clinical trials for the treatment of diarrhea. Furthermore, flavonoids including rutin and quercitrin have been detected in Croton campestris. Regarding gastroprotective mechanisms, evidence suggests that extracts and essential oils obtained from Croton species may act through the nitric oxide pathway, promoting an antiulcerogenic effect. Additional studies are needed to investigate the gastroprotective and antiulcerogenic potential of at least 17 Croton species used empirically in traditional medicine for the treatment of gastrointestinal disorders but still without scientific validation.

Compounds doi: 10.3390/compounds6010001

Authors: Yana Gvozdeva

Background: Powdered mucilages are increasingly being used as natural excipients in pharmaceutical formulations, functioning as binders, disintegrants, thickeners, suspending agents, and film formers. Their swelling, viscosity-enhancing, and biocompatible properties also make them useful in controlled-release systems and tablet production. This study aimed to produce spray-dried Cydonia oblonga (CO) mucilage, examine how drying parameters influence yield, and determine its physicochemical and rheological characteristics to evaluate its suitability for pharmaceutical applications. Methods: Powdered CO mucilage was obtained by spray drying. The obtained powders were characterized on yield, particle size and morphology, moisture content, loss on drying, flow properties and swelling index. Results: The obtained powders show yields of 10.6–16.4%, particle sizes of 4.5–5.39 μm, and moisture contents of 2–3%. Their flowability is limited despite satisfactory angle of repose, Hausner ratio, and Carr index values, yet all powders exhibit excellent swelling properties. Conclusions: Model CM6 of the obtained powdered CO seeds hydrocolloid stands out as the best spray-dried hydrocolloid, combining high drying efficiency, low residual moisture, uniform particle formation, and excellent swelling capacity despite its limited flowability. These properties make it a strong candidate for use as a biopolymer or excipient in pharmaceuticals.

Compounds doi: 10.3390/compounds5040061

Authors: Filomena Monica Vella Domenico Cautela Bruna Laratta

For centuries, people have used herbs, plants, and spices as remedies for health problems or simply to ameliorate body energy or vitality because of the bioactive compounds they contain. The Capsicum genus, which includes the chili pepper, is one of the oldest crops to be domesticated and used. It is characterized by three qualities: pungency/flavor, color, and aroma. Capsaicinoids are responsible for the pungent flavor. Carotenoids and flavonoids determine the remarkable and colorful tones of chili peppers. Volatile compounds provide their characteristic aroma. This prompts consumers to purchase and utilize the numerous varieties of chili peppers, whether fresh or dried. The presence of these bioactive compounds gives chili peppers functional attributes that promote health. This paper reviews the scientific research carried out over the last 25 years on these attributes. This paper also looks at how Capsicum fruits could be used as a valuable source of nutrients from plants that have beneficial biological properties.

Compounds doi: 10.3390/compounds5040060

Authors: Petar Batinić Natalija Čutović Jelena Marinković Aleksandar Krstić Stanislava Čukić Mirjana Pešić Danijel Milinčić Tatjana Marković

Chamomile (Matricaria chamomilla L.) and feverfew (Tanacetum parthenium L. Sch. Bip.), both members of the Asteraceae family, are widely distributed in Serbia and traditionally used for their medicinal properties. Chamomile is primarily known for its gastrointestinal effects, while feverfew is noted for its antimigraine activity. Although the biological activity of each plant has been individually studied, there has been a lack of research related to their blends. So, the aim of this study was to prepare various chamomile/feverfew blends and their extracts with special focus on extraction temperature, to obtain superior herbal extract with the best functional characteristics. In order to characterize the obtained blend extracts this study included spectrophotometric and UHPLC Q-ToF MS analysis of prepared (selected) extracts, as well as evaluation of their antioxidant (ABTS, DPPH, FRAP, and CUPRAC) and antimicrobial properties. Antibacterial activity was evaluated against two Gram-positive and four Gram-negative bacterial strains using the broth microdilution method. Untargeted analysis showed the same phytochemical profile for both selected extracts (B3 and B9), as well as differences in distribution and abundance of identified compounds depending on applied extraction temperature (cold or heat-assisted). These differences in profile most probably contributed to variations in the antioxidant and antimicrobial properties of the extracts. The most potent antioxidant activity (123.04 µM TEAC/g) was observed for the 3:1 feverfew/chamomile blend (ABTS assay), while the highest metal-chelating capacity (1288.95 µM VCEAC/g) was recorded in extracts obtained by heat-assisted extraction (CUPRAC assay). Antibacterial activity of all blends ranged from 0.625 to 2.5 mg/mL, regardless of the extraction method. The findings indicate that combined extracts of chamomile and feverfew represent a promising source of bioactive compounds with potential applicability in both food science and pharmaceutical (biomedical) research.

Compounds doi: 10.3390/compounds5040059

Authors: Masaki Nagaoka Hiroaki Chihara Shintaro Kodama Takeshi Maeda Shin-ichiro Kato Shigeyuki Yagi

Thermally activated delayed fluorescence (TADF) often achieves high device efficiencies in organic light-emitting diodes. Here we develop TADF dyes, 1-H and 1-Me, based on an N,N-diphenylaminophenyl–phenylene–quinoxaline donor–π–acceptor system, which contains an unsubstituted 1,4-phenylene and a 2,5-dimethyl-1,4-phenylene π-spacer, respectively. In UV–vis absorption spectra in toluene at room temperature, 1-H showed a relatively intense shoulder band at 400 nm, whereas 1-Me had a weak, blue-shifted shoulder at 386 nm, indicating 1-Me adopts a more twisted π-conjugation system. On the other hand, the photoluminescence (PL) wavelength of 1-Me (λPL; 558 nm) under the same conditions was slightly red-shifted in comparison with that of 1-H (λPL; 552 nm), due to larger structural relaxation of 1-Me. From PL lifetime measurements, both the dyes showed TADF in 10 wt%-doped poly(methyl methacrylate) film, and their PL quantum yields were moderate (ΦPL; ca. 0.5 at 300 K). As for the photokinetics, 1-Me exhibited larger rate constants for intersystem crossing and reverse intersystem crossing than 1-H due to the small excited-state singlet–triplet energy gap (ΔEST) of 1-Me. Furthermore, theoretical calculations indicated the triplet state of 1-Me is destabilized by localization of the spin density, resulting in the reduced ΔEST to facilitate TADF.

Compounds doi: 10.3390/compounds5040058

Authors: Yana K. Levaya Karakoz Zh. Badekova Mussa E. Zholdasbayev Gulnissa K. Kurmantayeva Gayane A. Atazhanova Daniyar T. Sadyrbekov Ainabayev Assanali

Salvia dumetorum Andrz. ex Besser is a promising non-pharmacopoeial plant species with traditional medicinal potential. This study aimed to determine the optimal microwave-assisted extraction (MAE) conditions for obtaining a polyphenol-rich ethanolic extract from the S. dumetorum leaves. Dried and powdered leaves were extracted using 40% ethanol with different power of microwaves varying from 200 to 800 W and time of extraction 2–8 min. The extract was filtered, concentrated, and evaluated for yield, identification of phenolic compounds using high-performance liquid chromatography (HPLC), total phenolic content (TPC), and total flavonoid content (TFC). Extraction yields ranged from 2.20% to 25.80% based on dry weight. TPC and TFC were determined using Folin–Ciocalteu and aluminum chloride colorimetric assays, respectively, and are expressed as mg GAE/g and mg RUE/g of dry extract. The antioxidant activity of the extracts was evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl radical) assay. According to HPLC analysis, the main phenolic components of the extracts were rosmarinic acid (1.78–2.95 mg/mL), chlorogenic acid (0.31–0.54 mg/mL), caffeic acid (0.11–0.20 mg/mL), rutin (up to 0.47 mg/mL) and ferulic acid (0.13–0.33 mg/mL); traces of myricetin were found only in isolated samples. The optimum extraction conditions were found to be 400 W microwave power, 8 min extraction time, one MAE cycle, and a 1:30 g/mL solvent-to-material loading ratio; TPC and TFC were evaluated as 35.23 ± 0.50 mg GAE/g DW and 19.94 ± 0.14 mg RuE/g DW, respectively, indicating the highest yield of polyphenolic compounds, antioxidant potential inhibiting 96.68% ± 0.27 of DPPH radicals, and IC50 = 10.24 µg/mL. These findings highlight the efficiency of MAE in producing a bioactive ethanolic extract of S. dumetorum, which can be further explored for potential applications as a natural antioxidant in pharmaceutical or cosmetic formulations.

Compounds doi: 10.3390/compounds5040057

Authors: Dana Ortiz-Ortiz Sonia J. Bailón-Ruiz

Antibiotics are increasingly detected in aquatic environments, raising environmental and public health concerns due to their persistence and contribution to antimicrobial resistance. This study examines copper sulfide (CuS) nanostructures as potential materials for sustainable water remediation. CuS nanoparticles were synthesized in aqueous media using thioglycolic acid (TGA) as a stabilizing ligand and characterized by UV–Vis, FTIR, XRD, TEM, SEM, and EDS. An optimized Cu:TGA molar ratio of 1:6 yielded stable nanoparticles with a distinct excitonic absorption at 312 nm, strong ligand coordination, and a covellite-type hexagonal crystalline phase. These nanoparticles were subsequently immobilized within calcium–alginate hydrogel beads of two controlled size regimes, producing structurally uniform and recoverable composites. SEM imaging revealed qualitative increases in surface texturing following CuS incorporation, while bead diameter analyses indicated minimal changes in morphology. Overall, the results confirm the successful synthesis, stabilization, and immobilization of CuS nanoparticles within alginate beads and establish a robust materials platform with potential for future adsorption and photocatalytic applications targeting antibiotic contaminants in water.

Compounds doi: 10.3390/compounds5040056

Authors: Yuriy S. Tveryanovich Andrey S. Tverjanovich Vladimir V. Tomaev Anton S. Mazur Svyatoslav S. Lun’kov Sonya A. Zaytseva Eugene Bychkov

The effect of Ag2Se content on the structure and mechanical properties of (1−x) (0.73GeSe2-0.27Sb2Se3)-xAg2Se glasses is analyzed. The glass structure is studied using XRD and NMR analyses. A particular consideration relates to a multiple increase in plasticity with increasing silver selenide content in chalcogenide glasses. The observed effects are attributed to the formation of silver–silver metallophilic interactions.

Compounds doi: 10.3390/compounds5040055

Authors: Alma Delia Noriega-Juárez Yolanda Nolasco-González Oswaldo Alejandro Arellano-Machuca Diego Rafael Montoya-Carvajal Brandon Alexis López-Romero Javier Alberto Navarro-Mendoza Efigenia Montalvo-González

Stenocereus fruits are appreciated for their flavor and color, and their cultivation is highly sustainable, as they grow in arid zones without the need for fertilizers or agrochemicals. However, their nutritional and bioactive composition remains underexplored. This study evaluated the physicochemical and nutritional properties, bioactive compound content, and antioxidant capacity (AOX) of Stenocereus thurberi (red, white, purple, and orange), Stenocereus martinezzi (red), and Stenocereus gummosus (red). All fruits exhibited low total soluble solids (12.6 ± 0.2–14.7 ± 0.3 °Brix), acidity (0.81 ± 0.03–1.12 ± 0.03%), and moderate dietary fiber content (3.71 ± 0.05–4.86 ± 0.09%). S. martinezzi stood out for its high levels of betalains (33.7 ± 0.65 mg/100 g_fw), vitamin E (84.7 ± 0.2 µg/100 g_fw), and vitamin C (147.6 ± 11.4 mg/100 g_fw). At the same time, potassium, magnesium, and calcium were the predominant minerals in all samples. S. gummosus showed the highest total soluble phenols (120.6 ± 2.2 mg/100 g_fw) and was also notable for its flavonoid content. Flavonoids, hydroxycinnamic, and hydroxybenzoic acids were detected in all fruits. Red fruits had the highest AOX levels, followed by white, orange, and purple varieties. In conclusion, these fruits are nutritious, low in sugars, and rich in bioactive compounds, suggesting their potential as functional foods, particularly beneficial for individuals with chronic degenerative diseases.

Compounds doi: 10.3390/compounds5040054

Authors: W. R. Agami H. M. Elsayed A. M. Faramawy

The influence of vanadium substitution on the structure, elastic, mechanical, and magnetic behavior of lithium ferrite (Li0.5+xVxFe2.5−2xO4; x = 0.00–0.2) was systematically studied. X-ray diffraction (XRD) was used to investigate the crystal structure, and infrared spectroscopy (IR) was used to determine the cation distribution between the two ferrite sublattices, in addition to the elastic and mechanical behavior of Li0.5+xVxFe2.5−2xO4 ferrites. X-ray analysis revealed a monotonic decrease in lattice parameter from 8.344 Å to 8.320 Å with increasing V5+ content, confirming lattice contraction and stronger metal–oxygen bonding. Despite a moderate increase in porosity (from 6.9% to 8.9%), the elastic constants C11 and C12 increased, indicating improved stiffness and reduced compressibility. The derived Young’s, bulk, and rigidity moduli rose with the doping of V5+. Correspondingly, the longitudinal, shear, and mean velocities (Vl, Vs, and Vm) increased. The Debye temperature also showed a linear rise from 705 K to 723 K with V5+ doping, directly reflecting enhanced lattice stiffness and phonon frequency. Furthermore, both the saturation magnetization (MS) and the initial permeability (μi) increased up to V5+ concentration x = 0.1 and then decreased. Curie temperature (TC) decreased with increasing V5+ concentration, while both the saturation magnetization (MS) and the initial permeability (μi) increased up to V5+ concentration x = 0.1 and then decreased, while the coercivity (HC) showed the reverse trend. These results confirm that V5+ incorporation significantly enhances the Li ferrite, improving its elastic strength, lattice energy, thermal stability, and magnetically controlling properties and making them suitable for a variety of daily uses such as magneto-elastic sensors, high-frequency devices, and applications requiring mechanically robust ferrite materials.

Compounds doi: 10.3390/compounds5040053

Authors: José C. Diez Edwin A. Baquero Virginia Rubio Juan C. Flores Angel Herráez M. Cristina Tejedor Ernesto de Jesús Ana I. García-Pérez

The purpose of this work was to study water-soluble platinum complexes as potential therapeutic agents. We used water-soluble platinum(II) complexes containing sulfonated N-heterocyclic carbene ligands (NHC), applied on two human cell models: human NB4 acute promyelocytic leukemia and PC3 prostatic cancer cells. We studied the toxic effects on these two types of human tumor cells. We analyzed metabolic activity, membrane damage, cell cycle, DNA fragmentation and programmed cell death. In human NB4 leukemia cells, the water-soluble dimethyl NHC complex 5Me proved highly toxic. It extinguished cell metabolism at 1 mM for 24 h. This treatment gave rise to the presence of fragmented DNA (subdiploid DNA). This compound promoted programed cell death in 60% of the cells. At longer times, the treatments produced neither higher fragmentation of DNA nor augmented apoptosis. 5Me complex, at 100 µM, showed slight toxicity on NB4 cells. In PC3 cells, dimethyl complex 5Me (1 mM for 24 h) is less toxic (reduced DNA fragmentation and programmed cell death) than in NB4 cells. Mono-NHC complexes 4 and 5 treatments at a high concentration for 24 h on PC3 cells produced apoptosis (30% of the cells) but their damage on cell permeability and DNA fragmentation was weak. Thus, PC3 cells are more resistant to NHC platinum(II) complexes than NB4 cells.

Compounds doi: 10.3390/compounds5040052

Authors: Alberto Santoni Marcello Cabibbo Gianni Virgili Eleonora Santecchia Kamal Sleem Gabriele Grima

This study explores the application of lattice structures as internal support architectures in the fabrication of Inconel 718 components via Laser Powder Bed Fusion (L-PBF), building upon previous research on beam-based FCCZ supports. Two representative lattice typologies were investigated: the node and beam-based FCCZ (face centered cubic with Z direction reinforcement struts) structure and the triply periodic minimal surface (TPMS) Schoen Gyroid cell. The aim was to assess how the transition from a discrete beam-node architecture to a continuous surface topology influences manufacturability, thermal stability, and mechanical performance. Finite Element Method (FEM) simulations in Ansys accurately predicted distortions and residual stresses during the L-PBF process, showing strong agreement with stereomicroscope measurements. Specifically, the maximum directional deformation reached 0.32 mm for the FCCZ sample versus 0.17 mm for the Gyroid, with corresponding peak residual stresses of 1328 MPa and 940 MPa, respectively. After fabrication, the samples underwent solution treatment and double aging according to AMS 2774 and AMS 5662 standards. Vickers microhardness increased from about 320 HV0.3 in the as-built condition to 500 HV0.3 after heat treatment (+55%), with overall porosity remaining below 1%. Microstructural analysis using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) revealed that heat treatment partially homogenized the microstructure but did not achieve complete recrystallization, leaving localized dendritic regions and undissolved Laves phases, particularly near the lattice. The precipitation of γ′ and δ phases enhanced hardness and mechanical uniformity, as confirmed by Vickers microhardness testing. Quantitatively, the Gyroid topology exhibited approximately 40% lower deformation and defect density than the FCCZ structure, confirming its superior manufacturability and thermal stability. These findings provide practical guidance for selecting lattice topologies for support architectures in L-PBF Inconel 718 components where thermal stability and shape preservation during build are critical.

Compounds doi: 10.3390/compounds5040051

Authors: Nikoleta Lugonja Dalibor Stanković

Dietary supplements often promote their antioxidant content as an indicator of quality on the packaging. This study evaluated the redox potential and total antioxidant capacity of various dietary supplements, using different analytical methods to obtain the complexity of antioxidant measurements. A green approach for detecting total antioxidant capacity in dietary products utilized modern electrochemical techniques, including differential pulse voltammetry (DPV) and cyclic voltammetry (CV). These rapid “green” methods measure the redox potential of samples, providing information about the electron-donating ability of antioxidants without the use of harmful chemicals or sample treatments, with minimal environmental impact. ABTS and FRAP measurements were expressed as vitamin C equivalents to allow comparison with CV measurements and actual vitamin C content. This approach enabled indirect comparison of activities obtained using different standard substances through conversion to standard equivalents. The results revealed that the claims made on product labels and packaging often overestimated the antioxidant content and did not match the measured total antioxidant capacities obtained in the current study. Measured vitamin C levels in 10 samples fell within the declared ranges (0–950 mg), but six products contained 4.85% to 49.18% less, and two had significantly higher levels (4.20% and 32.22%) than their declared (p < 0.05). Total antioxidant capacity varied from the labeled values. Similar trends were observed across methods, except for DPPH. FRAP values were correlated with ABTS and CV (r = 0.797 and r = 0.757, respectively). The DPV method provided a more detailed assessment of the redox activity of selected products based on distinct oxidation peaks. The study highlights the importance of mandatory testing and quantification of antioxidants, as well as the need for regulation of antioxidant properties through normative standards.

Compounds doi: 10.3390/compounds5040050

Authors: Mariana Panţuroiu Mona Luciana Gălăţanu Carmen Elisabeta Manea Mariana Popescu Roxana Colette Sandulovici Emilia Pănuş

Matricaria chamomilla and Tripleurospermum inodorum (syn. Matricaria inodora) are two closely related species in the Asteraceae family that are often mistaken for one another due to their similar appearance. However, they differ significantly in their chemical composition and biological activities. This study offers comparative characterisation through microscopy, phytochemical profiling, and biological assays. Microscopic observations revealed distinct morphological differences in the structure of the receptacle and the size of the pollen grains between the two species. Total phenol and flavonoid contents were quantified using spectrophotometry, while essential oils were extracted through hydrodistillation and analysed by gas chromatography–mass spectrometry (GC-MS). M. chamomilla was found to have a higher phenol content (20.48 mg GAE/g DW), whereas T. inodorum showed a greater flavonoid concentration (15.93 mg RE/g DW). The essential oils from each species displayed different chemical composition: M. chamomilla was dominated by bisabolol oxides and chamazulene, while T. inodorum primarily contained β-farnesene and cis-lachnophyllum ester. The antioxidant activity of both species was evaluated using the DPPH assay and found to be moderate compared to standard antioxidants, such as ascorbic acid (IC50 < 5 µg/mL). The IC50 values for M. chamomilla ranged from 17.7 to 21.5 µg/mL, while for T. inodorum, they ranged from 8.4 to 10.2 µg/mL. In antimicrobial tests, the essential oil of T. inodorum inhibited both Staphylococcus aureus and Candida albicans, while M. chamomilla was only active against C. albicans. These findings highlight important morphological and chemical markers that differentiate the two species and affirm T. inodorum as a promising source of bioactive compounds.

Compounds doi: 10.3390/compounds5040049

Authors: Karima Ait Alla Othman El Faqer Sanae Jahjah Amina Labhar Chaima Alaoui Jamali Ayoub Kasrati Badredine Souhail Mounir Legssyer Abdelfettah Maouni Rabah Saidi

Essential oils (EOs) from aromatic plants are valuable sources of bioactive compounds with potential applications as natural antimicrobials and antioxidants. This study investigated the chemical composition, antimicrobial and antioxidant activities, and in silico pharmacological properties of EOs extracted from Laurus nobilis, Thymbra capitata, and Mentha piperita, three medicinal species traditionally used in northern Morocco. Hydrodistillation yielded 1.12–1.53% oils, and GC–MS analysis revealed distinct chemotypes: L. nobilis was rich in eucalyptol, linalool, methyleugenol, and α-terpinyl acetate; T. capitata was dominated by carvacrol (80.95%), and M. piperita contained high proportions of linalool (57.37%) and linalyl acetate (28.56%). Antimicrobial assays demonstrated strong activity of all oils against Gram-positive and Gram-negative bacteria as well as Candida species, with T. capitata showing the most potent and broad-spectrum effects (MIC 0.073–9.47 mg/mL), attributed to its high carvacrol content. Antioxidant assays (DPPH and ferric reducing power) identified L. nobilis as the most active radical scavenger (IC50 = 0.037 mg/mL), followed by T. capitata, whereas M. piperita displayed weaker activity. PCA confirmed that phenolic monoterpenes drive both antimicrobial and antioxidant potency, while oxygenated terpenes and sesquiterpenes contribute more selectively. ADMET predictions indicated generally favorable absorption and low toxicity, although o-cymene and carvacrol presented potential safety concerns. Molecular docking revealed α-terpinyl acetate as the most versatile ligand, with strong binding to bacterial, fungal, and oxidative enzymes, whereas other compounds exhibited more selective affinities. Collectively, these findings highlight the potential of Moroccan EOs, particularly T. capitata and L. nobilis, as promising natural alternatives to synthetic antimicrobial and antioxidant agents.

Compounds doi: 10.3390/compounds5040048

Authors: Filip Herzyk Małgorzata Korzeniowska Tomasz Krusiński

Currant pomaces were valorised using food-grade supercritical CO2 to examine how pre-drying (convective vs. freeze-drying) and species (black vs. red currant) shape extract composition and antioxidant readouts. Total phenolics (TPCs), DPPH capacity, tocopherols and fatty acids were determined; statistics employed included the Welch test with Holm adjustment and one-way ANOVA. Blackcurrant showed consistently higher TPCs than redcurrant, whereas DPPH responses were maximised in freeze-dried redcurrant. Freeze-drying increased PUFAs and concomitantly lowered SFAs within both species, with MUFAs varying within a narrower band and tending to be higher in blackcurrant. Tocopherol profiles in residues displayed homologue- and species-specific redistribution (e.g., α higher after convective drying in blackcurrant; γ/δ preferentially retained after freeze-drying), consistent with microstructure-dependent mass transfer and homologue-specific partitioning during SFE. Collectively, pre-drying emerged as the principal lever to tailor lipid class balance and antioxidant performance under fixed extraction conditions. Practically, freeze-drying is suited to PUFA-rich, antioxidant-active fractions, whereas convective drying favours more oxidation-resilient profiles. These results support process-informed ingredient design for clean-label applications and motivate yield-normalised mass balances and scale-up studies.

Compounds doi: 10.3390/compounds5040047

Authors: Joana Nunes Rui Medeiros Matheus Chagas Melonio Cláudia Quintino da Rocha Fátima Cerqueira

Parkia platycephala has emerged as a promising medicinal species, attracting growing scientific interest due to its richness in bioactive compounds such as phenolic acids, flavonoids, tannins, saponins, terpenes, and lectins, present across different parts of the plant. Studies to date have highlighted its varied biological activities, including antioxidant, anti-inflammatory, antimicrobial, and antitumoral properties. Additionally, these compounds have been shown to increase the efficacy of conventional therapeutic drugs and reduce resistance to their effects. Given the breadth and relevance of these findings, compiling and systematizing the available data on P. platycephala is essential. A comprehensive synthesis not only facilitates a better understanding of the plant’s phytochemical and pharmacological potential but also lays the groundwork for the development of innovative, multi-target therapeutic strategies. This effort is particularly relevant in addressing current challenges in treating infections, inflammatory disorders, and cancer, thereby reinforcing the species’ value as a strategic resource for future drug discovery and integrative medicine.

Compounds doi: 10.3390/compounds5040046

Authors: Xuyen Thi Nguyen Phuong Thi Thu Pham Uyen Thu Pham Duong Thanh Nguyen Doanh Van Nguyen Tung Quang Nguyen

Aged green tea leaves, particularly from Shan Tuyet trees, represent an underutilized source of catechins—key antioxidant compounds with known health benefits. This study aims to optimize and compare three green extraction methods—Hot Water Extraction (HWE), Ultrasound-Assisted Extraction (UAE), and Ethanol–Water Extraction (EthE)—for catechin recovery from mature tea leaves. A Box–Behnken design (BBD) under Response Surface Methodology (RSM) was used to evaluate the effects of different extraction conditions. Total catechin content was quantified by HPLC, and antioxidant activities were measured using DPPH, FRAP, ORAC, and cellular antioxidant activity (CAA) assays. Results showed that while UAE and HWE produced total catechin yields of 206.0 mg/g and 202.0 mg/g, respectively, their biological efficacy was profoundly different. HWE, operating at a higher temperature (82 °C), induced significant thermal degradation, evidenced by high levels of catechin epimerization (EGCG/GCG ratio = 3.62) and hydrolysis. This loss of structural integrity resulted in the lowest cellular antioxidant activity (CAA) of 98.3 µmol QE/g. In contrast, the optimized UAE process (78 °C, 55 min, 290 W) preserved catechin stereochemistry (EGCG/GCG ratio = 9.86), yielding the highest CAA (185.2 µmol QE/g). These findings demonstrate that UAE acts as the optimal green strategy for producing high-yield, functionally superior extracts from mature tea leaves.

Compounds doi: 10.3390/compounds5040045

Authors: Míriam C. Pérez Mónica García Gustavo Pasquale María V. Laitano Gustavo Romanelli Guillermo Blustein

Biofouling by mussels is responsible for serious economic losses worldwide. In Argentina, Limnoperna fortunei (Dunker, 1857) and Brachidontes rodriguezii (d’Orbigny, 1842) are common and abundant bivalve species of great interest, inhabiting freshwater and marine coasts, respectively. Both species are considered fouling pests for coastal industrial facilities that use untreated water as part of their processes. To chemically control mussel biofouling, it is necessary to find efficient and environmentally friendly non-biocidal compounds. In this work, we report the antifouling activity of three phenolic compounds (hydroquinone, resorcinol, and catechol) and their respective acetylated derivatives against L. fortunei and B. rodriguezii mussels. Classic ecotoxicity tests with Artemia salina were also performed. Acetylated phenolic compounds were synthesized in the laboratory by sustainable chemistry procedures. Results revealed the importance of hydroquinone, resorcinol, and catechol and their diacetylated derivatives for preventing the settlement of both these mussels, in a non-biocide way. Ecotoxicity bioassays revealed that these compounds were not toxic, with the exception of resorcinol. We propose the incorporation of these compounds in solution into closed circuits and water sprinkler anti-fire systems to prevent the settlement of L. fortunei and their inclusion in antifouling paints to prevent the settlement of B. rodriguezii. These results highlight a new friendly alternative for controlling mussels.

Compounds doi: 10.3390/compounds5040044

Authors: Sun Jeong Im Alan J. Mlotkowski H. Bernhard Schlegel Christine S. Chow

Nucleobases play diverse structural and functional roles in biological systems. Understanding the fundamental properties of nucleobases is important for their applications as chemical probes of nucleic acid function. As the nucleobases are modified to tune their fluorescence or binding properties, their physical properties such as pKa may also change. Unlike the canonical nucleobases, modified nucleobases are less well understood in terms of their acid-base properties. Previously, theoretical pKa values of canonical, naturally modified, and aza-/deaza-modified nucleobases were determined. In this study, the theoretical pKa values for 25 different fluorescent modified nucleobases (55 total pKa values) were calculated by using an ab initio quantum mechanical method employing the B3LYP density functional with 6-31+G(d,p) basis set along with an implicit–explicit solvation model. The results of these computations are compared to known experimental pKa values. The ability to estimate theoretical pKa values will be beneficial for further development and applications of fluorescent nucleobases.

Compounds doi: 10.3390/compounds5040043

Authors: Kayim Pineda-Urbina Gururaj Kudur Jayaprakash Juan Pablo Mojica-Sánchez Andrés Aparicio-Victorino Zeferino Gómez-Sandoval José Manuel Flores-Álvarez Ulises Guadalupe Reyes-Leaño

Organophosphate pesticides are among the most persistent and toxic contaminants in aquatic environments, requiring effective strategies for detection and remediation. In this work, density functional theory (DFT) calculations were employed to investigate the adsorption of nine representative organophosphates (glyphosate, malathion, diazinon, azinphos-methyl, fenitrothion, parathion-methyl, disulfoton, tokuthion, and ethoprophos) on mercaptobenzothiazole disulfide (MBTS) and MBTS-functionalized graphene (G–MBTS). All simulations were performed in aqueous solution using the SMD solvation model with dispersion corrections and counterpoise correction for basis set superposition error. MBTS alone displayed a range of affinities, suggesting potential selectivity across the organophosphates, with adsorption energies ranging from 0.27 to 1.05 eV, malathion being the strongest binder and glyphosate the weakest. Anchoring of MBTS to graphene was found to be highly favorable (1.26 eV), but the key advantage is producing stable adsorption platforms that promote planar orientations and π–π/dispersive interactions. But the key advantage is not stronger binding but the tuning of interfacial electronic properties: all G–MBTS–OP complexes show uniform, narrow HOMO-LUMO gaps (∼0.79 eV) and systematically larger charge redistribution. These features are expected to enhance electrochemical readout even when adsorption strength was comparable or slightly lower (0.47–0.88 eV) relative to MBTS alone. A Quantum Theory of Atoms in Molecules (QTAIM) analysis of the G–MBTS–malathion complex revealed a dual stabilization mechanism: multiple weak C–H⋯π interactions with graphene combined with stronger S⋯O and hydrogen-bonding interactions with MBTS. These results advance the molecular-level understanding of pesticide–surface interactions and highlight MBTS-functionalized graphene as a promising platform for the selective detection of organophosphates in water.

Compounds doi: 10.3390/compounds5040042

Authors: Ruihan Yang Hao Guan Jiayan Jin Tianran Zheng Limin He Yongli Zhang Luyan Tian Jianfei Wang Xiangguang Li

Boron-dipyrromethene (BODIPY) has attracted extensive research attention in recent years due to its excellent photophysical properties, good chemical stability, and structural tunability, demonstrating broad application in fields such as fluorescence imaging, electroluminescence, biosensing and medical diagnostics. Researchers have extensively studied the synthesis, properties, and applications of BODIPY derivatives. This review summarizes five synthetic methods for the BODIPY core, with comparative analysis of their respective advantages, limitations and applicable scopes, aiming to provide valuable references for the future design and synthesis of BODIPY derivatives.

Compounds doi: 10.3390/compounds5040041

Authors: Tatiana V. Safronova Hieu Minh Ngoc Le Tatiana B. Shatalova Albina M. Murashko Tatiana V. Filippova Egor A. Motorin Dmitry M. Tsymbarenko Daniil O. Golubchikov Olga V. Boytsova Alexander V. Knotko

Low-crystalline hydroxyapatite was synthesized from an aqueous solution of calcium chloride (CaCl2), and a mixed-anionic (HPO42− и CO32−) aqueous solution prepared from potassium hydrophosphate trihydrate (K2HPO4 3Н2О), and potassium carbonate (K2CO3). The interaction of K2CO3 and K2HPO4 salts during synthesis from a mixed-anionic solution in the reaction zone without additional regulation provided the pH level necessary for the synthesis of hydroxyapatite. For comparison, as references, powders were also synthesized from an aqueous solution of CaCl2 and from aqueous solutions of either K2HPO4 or K2CO3. The phase composition of the powder synthesized from aqueous solutions of CaCl2 and K2HPO4 included brushite (CaНРО4·2H2O). The phase composition of the powder synthesized from aqueous solutions of CaCl2 and K2CO3 included calcite (CaCO3). The phase composition of all synthesized powders contained potassium chloride (sylvine, KCl), as a reaction by-product. After heat treatment at 1000 °C of the powder containing low-crystalline hydroxyapatite and KCl, powder of chlorapatite (Са10(РО4)6Cl2) was obtained. After heat treatment of a powder containing brushite (CaНРО4·2H2O) and KCl at 800 and 1000 °C, a powder with the phase composition including β-calcium pyrophosphate (β-Ca2P2O7), β-calcium orthophosphate (β-Ca3(PO4)2), and potassium-calcium pyrophosphate (K2CaP2O7) was obtained. Heat treatment of calcite (CaCO3) powder at 800 °C, as expected, led to the formation of calcium oxide (CaO). Synthesized powders, including biocompatible minerals such as hydroxyapatite, chlorapatite, brushite, monetite, calcium pyrophosphate, calcium potassium pyrophosphate, tricalcium phosphate, and calcite, can be used for the creation of biocompatible inorganic materials or composite materials with a biocompatible polymer matrix. The potassium chloride present in the synthesized powders can act as one of the precursors of biocompatible minerals, such as chlorapatite or calcium potassium pyrophosphate, or it can be treated as a removable inorganic porogen.

Compounds doi: 10.3390/compounds5040040

Authors: Camila Millar-Obreque Vicente González-Muñoz Ana M. Marileo Bernardita Salgado-Martínez Krishna Gaete-Riquelme Oscar Ramírez-Molina Pamela A. Godoy Jorge Fuentealba Gonzalo E. Yévenes Carlos F. Burgos

Glycine receptors (GlyRs) are essential for inhibitory neurotransmission in the central nervous system (CNS) and represent promising targets against neurological disorders. Several indole alkaloids from Gelsemium species have been shown to modulate GlyRs. Notably, the anxiolytic and analgesic properties of certain Gelsemium alkaloids appear to depend on GlyR modulation. However, prior studies have focused on only a few indole alkaloids, leaving the activity of other Gelsemium compound classes unexplored. This study employed an integrative in silico approach to investigate the interactions between GlyR α1 and α3 subtypes and 162 structurally diverse Gelsemium compounds. Physicochemical, pharmacokinetic, and toxicological analyses identified compounds with favorable bioavailability in the CNS. Molecular docking revealed that indolic alkaloids bind the GlyR orthosteric site with profiles comparable to the reference Gelsemium compound, gelsemine. Molecular dynamics simulations confirmed the stability and conformational integrity of selected ligand-receptor complexes. Overall, novel potential GlyR modulators were identified, with several compounds showing a promising selectivity profile towards GlyR α1 and α3 subtypes. These findings further support the therapeutic potential of Gelsemium alkaloids and provide a foundation for further pharmacological and toxicological validation.

Compounds doi: 10.3390/compounds5040039

Authors: Konstantin A. Tereshchenko Nikolai V. Ulitin Rustem T. Ismagilov Alexander S. Novikov

An analysis was conducted to investigate how reaction system turbulence affects the butadiene-isoprene copolymerization in the presence of the TiCl4 + Al(i-Bu)3 catalytic system. A model was developed, which integrates CFD simulations of TiCl4 + Al(i-Bu)3 particle breakage based on population balance equations with the kinetic modeling of the butadiene-isoprene copolymerization. It was established that an increase in turbulent kinetic energy leads to a reduction in catalyst particle size, an increase in active site concentration, an acceleration of the copolymerization process, and a decrease in the average molecular weights of the copolymer. Furthermore, catalytic activity correlates with both the average and maximum values of turbulent kinetic energy in the reaction system, whereas the effect of the average residence time of catalytic particles under turbulent conditions is insignificant. Based on these results, recommendations were provided for optimizing the impact of reaction system turbulence on TiCl4 + Al(i-Bu)3 particles to enhance the butadiene-isoprene copolymerization rate and achieve precise control over the molecular weight characteristics of the copolymer. The findings of this study can be applied to optimize the synthesis technology of the cis-1,4 butadiene-isoprene copolymer, which is used in the production of frost-resistant rubber.

Compounds doi: 10.3390/compounds5040038

Authors: Sérgio P. Leite Laiza C. Krause Sona Jain Thiago R. Bjerk

Hancornia speciosa Gomes (H. speciosa) is present in several regions of Brazil. It is a plant traditionally used in the treatment of various diseases. This study aims to provide a comprehensive overview of scientific publications and patents related to H. speciosa, emphasizing its primary applications and potential utility. For scientific prospection, an extensive search for relevant publications was carried out in the Scopus database. For technological prospection, the Instituto Nacional de Propriedade Intelectual (INPI) and World Intellectual Property Organization (WIPO) databases were utilized. Research on H. speciosa spans across multiple domains, including agronomy, gastronomy, technology, and pharmaceuticals, revealing the identification of numerous pharmacologically interesting compounds, such as rutin, chlorogenic acid, bornesitol, and various triterpenes, such as Lupeol, α- and β-amyrin, and their respective acetates. Regarding patents, there is a notable emphasis on gastronomic applications, with only a limited number of patents dedicated to technological and health-related areas. The increasing interest in H. speciosa is evident from the various studies investigating the biological properties of its compounds, such as anti-inflammatory, antihypertensive, and antidiabetic actions. Additionally, there is significant potential for further exploration and advancement of research in the pharmaceutical and technological sectors.

Compounds doi: 10.3390/compounds5040037

Authors: Małgorzata Anna Marć Enrique Domínguez-Álvarez

The Special Issue with the title ‘Organic Compounds with Biological Activity’ [...]

Compounds doi: 10.3390/compounds5030036

Authors: Adrián Bogeat-Barroso María Francisca Alexandre-Franco Carmen Fernández-González Vicente Gómez Serrano

The present work is aimed at shedding light on the evolution of surface chemistry of a commercial activated carbon (AC) support during the preparation of supported metal oxide (MO) catalysts by the conventional wet impregnation method. Particular attention is paid to the chemical changes of oxygen-containing surface functionalities across three preparation stages of impregnation, oven-drying, and thermal treatment. AC was impregnated with aqueous solutions of several MO precursors (Al(NO3)3, Fe(NO3)3, Zn(NO3)2, SnCl2, and Na2WO4) at 80 °C for 5 h, oven-dried at 120 °C for 24 h, and heat-treated at 200 °C and 850 °C for 2 h under an inert atmosphere. The surface chemistry of the resulting catalyst samples, classified in three series by the thermal treatment, was mainly studied by FT-IR spectroscopy, complemented by elemental analysis and pH of the point of zero charge (pHpzc) measurements. During impregnation, phenolic hydroxyl and carboxylic acid groups were predominantly formed by wet oxidation of chromene, 2-pyrone, and ether-type structures found in the pristine AC. The extent of these oxidations correlated with the oxidising power of the precursor solutions. As expected, thermal treatment at 850 °C brought about markedly stronger chemical changes, with most of the above oxygen functionalities decomposing and forming less acidic structures, such as 4-pyrone groups, metal carboxylates, and C-O-M atomic groupings. All these surface chemical modifications result in a lowering of the strong basicity of the raw carbon support (pHpzc ≈ 10.5), thus leading to pHpzc values for the catalysts widely ranging from 1.6 to 9.7.

Compounds doi: 10.3390/compounds5030035

Authors: Javier E. Ortiz Camila W. Adarvez-Feresin Olimpia Llalla-Cordova Diego Cristos Adriana Garro Gabriela E. Feresin

Neurodegenerative diseases, including Alzheimer’s disease (AD), represent one of the main global health challenges. Cannabis sativa synthesizes spermidine-type alkaloids, whose potential biological activities have been little studied. This study aimed to isolate bioactive alkaloids from an alkaloid-enriched extract (AEE) of C. sativa roots throughout a bioguided approach using conventional chromatographic techniques based on AChE and BuChE inhibitory activities. A qualitative and semiquantitative analysis by UPLC-ESI-MS/MS as well as molecular modeling simulations were performed. In addition, predictive in silico analyses were conducted to assess toxicity properties. The alkaloids cannabisativine (CS) and anhydrocannabisativine (ACS) were isolated, and showed highly selective BuChE inhibitory activity. The molecular modeling study revealed a conserved interaction profile across both alkaloids, indicating the amino acids TRP82, GLU197, TYR440, and HIS438 as the major contributors involved in the complex formation. Finally, CS and ACS exhibited low in silico predictive toxicity values. In conclusion, CS and ACS alkaloids emerge as new selective BuChE inhibitors with therapeutic potential that deserves the attention from the field of pharmacology in neurodegenerative disease research. Additionally, this approach promotes innovation and environmental sustainability through the use of C. sativa roots.

Compounds doi: 10.3390/compounds5030034

Authors: Fatimah Al-Ghazzawi Mohammed Mahdi Al-Mossawi Hadeel K. Allayeith

Covalent organic framework (COF) membranes are eminent candidates in filtration and separation applications due to their high porosity, ordered pore size, versatile molecular structure, inherent mechanical properties, and excellent stability. However, large-scale COF membranes suffer from several issues, including stacking and crystal defects, which negatively impact their rejection performance. In this study, a continuous thin film of porphyrinic-based COF (i.e., COF-TCPP (Fe)) with various thicknesses was fabricated on a PVDF support layer via a vacuum-assisted interfacial polymerization method. The composite membranes were then characterized, and their filtration and dye/salt separation performance were evaluated using a dead-end filtration cell. The results showed that the rejection efficiencies of Congo red and acid fuchsin for the optimal proposed membrane were 99.5% and 95.8%, respectively. In comparison, the corresponding values for the pristine membrane were 73.3% and 62.8%. The results also showed that with an increase in the COF loading concentration during synthesis, the membrane flux decreased, while the rejection efficiency increased. This study proposes a simple and effective method to mitigate the large-scale issues of COF-based membranes and to enhance the separation performance of existing polymeric membranes.

Compounds doi: 10.3390/compounds5030033

Authors: Binghui Liang Qirui Ma Xianglei Gong Guohang Hu Hongwu Chen

Heyang Fragrance, a traditional incense dating back to the Eastern Han Dynasty (25–220 AD), was recently inscribed on China’s national list of intangible cultural heritage. This study aimed to systematically analyze three variants of Heyang Fragrance (Aicao, Qinqiang, and Jianjia) through integrated methodologies including electronic nose analysis, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), and antimicrobial activity assays. We selected Escherichia coli, Bacillus subtilis, and Candida glabrata for the antimicrobial activity assays. Comparative analysis revealed significant compositional differences between pre- and post-combustion volatile profiles. Upon ignition, sensor response values increased by 50–100% relative to baseline measurements, with sulfides, terpenes, and short-chain alkanes emerging as dominant components. Qinqiang demonstrated the highest odor activity values (OAVs), particularly through carvacrol (OAV = 6676.60) and eugenol (OAV = 2720.84), which collectively contributed to its complex aromatic characteristics. Antimicrobial assessments revealed concentration-dependent efficacy, with Qinqiang exhibiting broad antimicrobial activity against Escherichia coli (11.33 mm inhibition zone) and Bacillus subtilis (15.00 mm), while Jianjia showed maximal effectiveness against Bacillus subtilis (17.67 mm). These findings underscore the dual significance of Heyang Fragrance in cultural conservation and its prospective applications in aroma therapeutic and antimicrobial contexts.

Compounds doi: 10.3390/compounds5030032

Authors: Eirini Zagoraiou Olga Thoda Ekaterini Polyzou Anastasia Maria Moschovi Iakovos Yakoumis

The advancement of catalytic materials is critical to improving the performance, reducing the cost and enhancing the sustainability of Proton Exchange Membrane (PEM) fuel cells and electrolyzers. Although Platinum Group Metal (PGM)-based electrocatalysts exhibit high electrochemical activity, their limited availability and the environmentally intensive extraction pose significant challenges. This study aims to demonstrate the direct reuse of recycled impure platinum (Pt) precursors for the synthesis of effective Pt/C electrocatalysts as a viable step toward circular hydrogen economy implementation. A low-cost and eco-friendly chlorine-based hydrometallurgical method was successfully employed to recycle over 99% of Pt from End-of-Life (EoL) Membrane Electrode Assemblies (MEAs), with an industrial perspective. Recycled metal precursor was used without purification to synthesize Pt/C electrocatalyst via a scalable and sustainable method. The catalyst was structurally and chemically characterized, and their electrochemical performance towards the Oxygen Reduction Reaction (ORR) was conducted under conditions simulating real operating environments. The recycled-metal-derived catalyst demonstrated comparable activity toward ORR (170 A/gPt) relative to a commercial catalyst, indicating its potential as viable alternative to conventional PGM-based catalysts. By integrating energy-efficient recycling with advanced material design, this work supports the development of cost-effective and green solutions for clean energy technologies aligned with a circular hydrogen economy model.

Compounds doi: 10.3390/compounds5030031

Authors: Claudia Giovagnoli-Vicuña Rafael Viteri Javiera Aparicio Issis Quispe-Fuentes Ady Giordano

Amomyrtus luma (A. luma), a native Chilean tree species, produces fruits containing 1–3 non-edible seeds, which are typically discarded as waste during processing. This study evaluated the fatty acid composition and bioactive properties of A. luma seed oil obtained through maceration, ultrasound extraction, and Soxhlet extraction, using hexane as the extraction solvent. Fatty acid methyl esters (FAMEs) were quantified using gas chromatography-flame ionization detection (GC–FID), revealing that linoleic acid was the most abundant (79.79–80.09%), followed by oleic acid (8.89–9.18%) and palmitic acid (7.29–7.40%), with no significant differences (p < 0.05) among extraction methods. However, extraction conditions significantly influenced the concentration of bioactive compounds, including total phenolics, flavonoids, tannins, lycopene, carotenoids, and antioxidant capacity, as determined through DPPH and FRAP assays. A strong correlation was observed between polyphenol content and antioxidant activity, particularly in maceration and ultrasound extraction, whereas Soxhlet extraction favored tocopherols and carotenoids due to the thermal degradation of polyphenols. Soxhlet extraction yielded the highest oil recovery, while ultrasound extraction preserved the highest levels of bioactive compounds and antioxidant capacity. No antimicrobial activity was detected against Staphylococcus aureus and Escherichia coli. These findings underscore the key role of extraction methods in determining the nutritional and functional quality of A. luma seed oil. Given its high unsaturated fatty acid content and bioactive potential, A. luma seed oil represents a promising ingredient for cosmetic and pharmaceutical applications, while contributing to waste valorization and sustainable resource utilization.

Compounds doi: 10.3390/compounds5030030

Authors: Rafael Corrêa Ramos Lizandra G. Magalhães Rodrigo C. S. Veneziani Sérgio R. Ambrósio Renato Pereira Orenha Renato Luis Tame Parreira Márcio L. Andrade e Silva Jairo K. Bastos Murilo de Oliveira Souza Híllary Ozorio Gobeti Caprini Ana Carla Rangel Rosa Wanderson Zuza Cosme Mario F. C. Santos Wilson R. Cunha

Neglected diseases significantly impact the world, and there is a lack of effective treatments, requiring therapeutic alternatives. Thus, the study of the phytochemical and schistosomicidal activity evaluation of Copaifera oblongifolia leaves’ crude extract was conducted. The quercitrin (1) and afzelin (2) were isolated from the crude extract. In the in vitro schistosomicidal activity test, the isolated compounds demonstrated promising results, with 75% mortality at a concentration of 12.5 µM after 72 h. Molecular docking calculations indicated that compounds 1 and 2 could potentially interact with the amino acids of the FAD binding site in the TGR enzyme, a crucial enzyme for the survival of Schistosoma mansoni. These interactions could have binding energies comparable to praziquantel, a preferred drug for treating schistosomiasis. Therefore, in silico and in vitro investigations are crucial for developing new studies that can reveal the antiparasitic potential of compounds of plant origin.

Compounds doi: 10.3390/compounds5030029

Authors: Salome Mamani Parí Erick Saldaña Juan D. Rios-Mera María Fernanda Quispe Angulo Nils Leander Huaman-Castilla

Edible mushrooms are well-known for their culinary and nutritional values. Additionally, they serve as a natural source of polyphenols, a group of bioactive compounds that significantly treat diseases associated with oxidative stress. The polyphenolic profile of mushrooms mainly consists of phenolic acids and flavonoids, whose chemical properties have attracted the attention of both the food and pharmaceutical industries. Consequently, methods for extracting polyphenols from mushrooms encompass conventional techniques (maceration and Soxhlet extraction) as well as innovative or green methods (ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction, supercritical fluid extraction, enzyme-assisted extraction, and pulsed electric field extraction). Nonetheless, extraction with pressurized liquids and supercritical fluids is considered the most suitable method, as they function in a gentle and selective manner, preserving the integrity of the phenolic compounds. The use of mushroom-derived phenolic compounds in food and pharmaceutical formulations continues to face challenges concerning the safety of these extracts, as they might contain unwanted substances. Future applications should incorporate purification systems to yield highly pure extracts, thereby creating safe polyphenol carriers (for food and pharmaceutical products) for consumers.

Compounds doi: 10.3390/compounds5030028

Authors: André Gustavo Horta Barbosa João Guilherme Siqueira Monteiro Noemi de Jesus Hiller Daniela de Luna Martins

An important property of arylboronic acids, particularly when considering their use in medicinal chemistry, is their pKa in aqueous solution. The results of computational determination of absolute pKas of arylboronic acids can be very disappointing in comparison to available experimental results, particularly in the case of large substituents. In this paper, the main origin of this problem is identified. It is shown that in order to obtain accurate pKa values for arylboronic acids from computational quantum chemistry, it is necessary to consider the effect of different possible conformations of the hydroxyl groups in the acid and its conjugate base together with the low-energy conformations of their substituents. An improved practical procedure for the computational determination of the pKas of arylboronic acids is proposed and applied to a set of recently synthesized arylboronic acids, yielding consistent results.

Compounds doi: 10.3390/compounds5030027

Authors: Nadezhda Prokhorenkova Almira Zhilkashinova Madi Abilev Leszek Łatka Igor Ocheredko Assel Zhilkashinova

Multilayer thin films composed of cobalt (Co), carbon (C), and chromium (Cr) possess promising electromagnetic properties, yet the combined Co–C–Cr system remains underexplored, particularly regarding its performance as a microwave absorber. Existing research has primarily focused on binary Co–C or Co–Cr compositions, leaving a critical knowledge gap in understanding how ternary multilayer architectures influence electromagnetic behavior. This study addresses this gap by investigating the structure, phase composition, and microwave absorption performance of Co–C–Cr multilayer coatings fabricated via magnetron sputtering onto porous silicon substrates. This study compares four-layer and eight-layer configurations to assess how multilayer architecture affects impedance matching, reflection coefficients, and absorption characteristics within the 8.2–12.4 GHz frequency range. Structural analyses using X-ray diffraction and transmission electron microscopy confirm the coexistence of amorphous and nanocrystalline phases, which enhance absorption through dielectric and magnetic loss mechanisms. Both experimental and simulated results show that increasing the number of layers improves impedance gradients and broadens the operational bandwidth. The eight-layer coatings demonstrate a more uniform absorption response, while four-layer structures exhibit sharper resonant minima. These findings advance the understanding of ternary multilayer systems and contribute to the development of frequency-selective surfaces and broadband microwave shielding materials.

Compounds doi: 10.3390/compounds5030026

Authors: Elham Nadim Pavan Paraskar Emma J. Murphy Mohammadnabi Hesabi Ian Major

This review examines the chemical functionalization of Camelina, hemp, and rapeseed oils for the development of sustainable bio-based resins. Key strategies, including epoxidation, acrylation, and click chemistry, are discussed in the context of tailoring molecular structure to enhance reactivity, compatibility, and material performance. Particular emphasis is placed on overcoming the inherent limitations of vegetable oil structures to enable their integration into high-performance polymer systems. The agricultural sustainability and environmental advantages of these feedstocks are also highlighted alongside the technical challenges associated with their chemical modification. Functionalized oils derived from Camelina, hemp, and rapeseed have been successfully applied in various resin systems, including protective coatings, pressure-sensitive adhesives, UV-curable oligomers, and polyurethane foams. These advances demonstrate their growing potential as renewable alternatives to petroleum-based polymers and underline the critical role of structure–property relationships in designing next-generation sustainable materials. Ultimately, the objective of this review is to distill the most effective functionalization pathways and design principles, thereby illustrating how Camelina, hemp, and rapeseed oils could serve as viable substitutes for petrochemical resins in future industrial applications.

Compounds doi: 10.3390/compounds5030025

Authors: Oksana S. Patrusheva Irina V. Ilyina Nariman F. Salakhutdinov Stela T. Dragomanova Konstantin P. Volcho

Monoterpenes and their derivatives are important starting compounds in the design of new biologically active substances. In particular, cineole, isolated from eucalyptus essential oil, exhibits a wide range of biological activities. Here, the synthesis of new heterocyclic compounds containing a cineole fragment by the acid-catalyzed condensation of α-pinene-derived 8-hydroxy-6-hydroxymethyllimonene with monoterpene aldehydes was carried out for the first time. The reactions of 8-hydroxy-6-hydroxymethyllimonene with cuminaldehyde, perillylaldehyde, myrtenal, citral, and geranial were studied in the presence of heterogeneous K10 clay or Lewis acid BF3·Et2O. The main products of these reactions were compounds with the methanopyrano[4,3-b]pyran scaffold having a 1,8-cineole fragment. As a result of this work, five new compounds with the methanopyrano[4,3-b]pyran scaffold were synthesized. The use of BF3·Et2O led to an increase in the yields of target products, compared with the results obtained on K10 clay.

Compounds doi: 10.3390/compounds5030024

Authors: Valeri V. Mossine Steven P. Kelley Thomas P. Mawhinney

A quinoline unit is present in many natural products and is an attractive pharmacophore for the development of clinical drugs, including antineoplastics. The title compound (QN) was synthesized via the condensation reaction between quinoline-2-carboxaldehyde and 2-nitrobenzhydrazide. QN’s structure was examined by X-ray diffraction and features extensive stacking interactions in the crystal. The compound is weakly toxic to HepG2 cells, with an IC50 exceeding 400 μM for 48 h exposure. QN at 50 μM, with the dose reduction index in the range of 1.9–4.4, potentiated the cytotoxicity of several clinical chemotherapeutic drugs, including doxorubicin and other topoisomerase inhibitors, vincristine, and carboplatin, but not cisplatin or 5-fluorouracil. The calculated ADME parameters predict satisfactory drug-like properties for QN.

Compounds doi: 10.3390/compounds5020023

Authors: Macarena Agostina Biondi Mariana Belén Spesia María Carola Sabini María Alicia Biasutti Hernán Alfredo Montejano Eugenia Reynoso

Levofloxacin is an antibiotic classified as an emerging contaminant. Its presence in aquatic environments represents potential risks to ecosystems and human health, making its removal during wastewater treatment of relevant importance. Here, we present a comprehensive kinetic analysis of levofloxacin photodegradation under UVB solar irradiation, with emphasis on the influence of pH and dissolved oxygen, two conditions that can vary widely in wastewater and impact treatment efficiency. We also investigated the formation and role of reactive oxygen species in the degradation mechanism, as well as the cytotoxicity and antibacterial activity of photoproducts. Our findings reveal that the efficiency of levofloxacin photodegradation is highly dependent on environmental conditions; it requires neutral or slightly alkaline pH and a high concentration of dissolved oxygen, a situation not always observed in contaminated waters. Several reactive oxygen species are generated, with singlet oxygen being the most reactive with the antibiotic. We report for the first time the singlet oxygen quantum yield from levofloxacin. Bioassays demonstrated that photoproducts neither exhibit antibacterial activity nor induce significant cytotoxicity. Our study suggests that UVB treatment of contaminated effluent containing levofloxacin could be an effective and environmentally safe strategy for the antibiotic degradation under certain conditions of pH and dissolved oxygen.

Compounds doi: 10.3390/compounds5020022

Authors: Tatiana V. Safronova Alexandra S. Sultanovskaya Sergei A. Savelev Tatiana B. Shatalova Yaroslav Y. Filippov Olga V. Boytsova Vadim B. Platonov Tatiana V. Filippova Albina M. Murashko Xinyan Feng Muslim R. Akhmedov

Powders with phase composition including quasi-amorphous phases and calcium carbonate CaCO3 in the form of calcite or aragonite and sodium halite NaCl as a reaction by-product were synthesized from 0.5M aqua solutions of sodium silicate and 0.5M aqua solutions of calcium and/or magnesium chlorides. Starting solutions were taken in quantities which could provide precipitation of hydrated calcium and/or magnesium silicates with molar ratios Ca/Si = 1 (CaSi), Mg/Si = 1 (MgSi) or (Ca+Mg)/Si = 1 (CaMgSi). Hydrated calcium and/or magnesium silicates, hydrated silica, magnesium carbonate, hydrated magnesium carbonate or hydrated magnesium silicate containing carbonate ions are suspected as components of quasi-amorphous phases presented in synthesized powders. Heat treatment of synthesized powders at 400, 600, 800 °C and pressed preceramic samples at 900, 1000, 1100 and 1200 °C were used for investigation of thermal evolution of the phase composition and microstructure of powders and ceramic samples. Mass loss of powder samples under investigation during heat treatment was provided due to evacuation of H2O (m/z = 18), CO2 (m/z = 44) and NaCl at temperatures above its melting point. After sintering at 1100 °C, the phase composition of ceramic samples included wollastonite CaSiO3 (CaSi_1100); enstatite MgSiO3, clinoenstatite MgSiO3 and forsterite Mg2SiO4 (MgSi_1100); and diopside CaMgSi2O6 (CaMgSi_1100). After sintering at 1200 °C, the phase composition of ceramics CaSi_1200 included pseudo-wollastonite CaSiO3. After heat treatment at 1300 °C, the phase composition of MgSi_1300 powder included preferably protoenstatite MgSiO3. The phase composition of all samples after heat treatment belongs to the oxide system CaO–MgO–SiO2. Ceramic materials in this system are of interest for use in different areas, including refractories, construction materials and biomaterials. Powders prepared in the present investigation, both via precipitation and via heat treatment, can be used for the creation of materials with specific properties and in model experiments as lunar regolith simulants.

Compounds doi: 10.3390/compounds5020021

Authors: Walker Vinícius Ferreira do Carmo Batista Aniely Pereira de Souza Tais dos Santos Cruz Dilton Martins Pimentel Danila Graziele Silva de Avelar Sarah Karoline Natalino Oliveira Wanessa Lima de Oliveira Danilo Roberto Carvalho Ferreira Márcio Cesar Pereira Rondinele Alberto dos Reis Ferreira João Paulo de Mesquita

In this study, we report the synthesis and characterization of hybrid heterostructures composed of red carbon, an organic semiconductor polymer, and the perovskite (NH4)3ZnCl5. Red carbon was synthesized via the polymerization of carbon suboxide (C3O2), exhibiting strong light absorption and distinctive optical properties. The hybrid material was obtained by crystallizing (NH4)3ZnCl5 in the presence of red carbon, leading to significant modifications in the optical characteristics of the perovskite. Comprehensive analyses, including X-ray diffraction, FTIR spectroscopy, UV-vis spectroscopy, and cyclic voltammetry, confirmed the formation of a type I heterostructure with enhanced luminescence and potential for advanced optical applications. The energy band alignment suggests that red carbon can function effectively as both a hole and electron transport medium. This work underscores the potential of (NH4)3ZnCl5@red carbon hybrid heterostructures in the development of next-generation optoelectronic devices, including sensors and LEDs.

Compounds doi: 10.3390/compounds5020020

Authors: Victor C. Sousa Bruno Dival Willian X. C. Oliveira

This work describes the synthesis, crystal structure, and hydrophobicity tests of four bismuth(III)– and silver(I)–bromide complexes using the triammonium cations diethylenetriaminonium (H3DETA3+) and N,N,N′,N″,N‴-pentamethyldiethylenetriammonium (H3PMDTA3+). The prepared compounds are the 0D perovskites (H3DETA)[BiBr6] (1), (H3DETA)2[AgBr4]Br3 (2), and (H3PMDTA)[BiBr6] (3), as well as the 1D/2D mixed perovskite with minimum formula (H3PMDTA)[Ag3Br6] (4), being the last three novel materials. Compounds 1 and 3 crystallize in the orthorhombic P212121 space group and are discrete [BiBr6]3− units with the cation surrounding them. In both compounds, the bismuth(III) metal ion is found in a distorted octahedral coordination geometry. Compound 2 crystallizes in the monoclinic P21/c space group, and it is a mixed salt consisting of (H3DETA)[AgBr4] and (H3DETA)Br3, whereas the silver(I) complexes are also isolated. Finally, compound 4, which crystallizes in the orthorhombic space group Pbcn, is a combination of a 2D and 1D silver–bromide perovskite, with the cations filling the voids. The 2D structure has the minimal formula [Ag4Br7]3−, with the 1D coordination polymer [Ag2Br5]3− being both built up by a combination of bromide ions acting as tetrahedra corner and edge-sharing bridging ligands. The silver(I) in 2 and 4 is found in a tetrahedral coordination geometry. All compounds were deposited on pristine FTO glass, resulting in an increase in the contact angle from 22° to 44°, 36°, 62°, and 54° for films of 1, 2, 3, and 4, respectively. Compounds 1 and 3 were also deposited onto Cs2AgBiBr6 film, and the contact angles were observed to be the same as when deposited directly onto the FTO cover glass.

Compounds doi: 10.3390/compounds5020019

Authors: Bruna Fernanda Damasceno Ramirez Gustavo Aparecido Martins Juliano Lemos Bicas Mário Roberto Maróstica Júnior

The characterization of volatile compounds in cheese is crucial for understanding sensory properties and consumer acceptance. Camembert cheese, a surface-ripened variety, presents a complex aroma profile shaped by biochemical and microbial interactions. Despite advances in analytical methods such as gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O), the metabolic pathways and microbial interactions defining Camembert’s aroma remain incompletely understood. This review explores the synergistic roles of microbial communities, enzymatic activity, and environmental conditions in volatile compound formation. A systematic literature review was conducted using Scopus, Web of Science, and Google Scholar to analyze the classification of volatile compounds, biochemical pathways of aroma formation, and microbial contributions. The findings highlight the essential role of Penicillium camemberti and lactic acid bacteria in aroma modulation, particularly in sulfur compounds, esters, and short-chain fatty acids. Emerging technologies such as solid-phase microextraction (SPME) and metabolomics provide new insights into volatile compound dynamics. Understanding these mechanisms may enhance aroma control in cheese production through microbial engineering and biochemical monitoring. This review underscores the need for integrated approaches to optimize fermentation and ensure sensory standardization, contributing to improved quality and consumer acceptance of Camembert cheese.

Compounds doi: 10.3390/compounds5020018

Authors: Preeti Sharma Benjamin Barnes Raekayla Johnson Victoria V. Volkis

One of the most pressing issues confronting modern society is carbon dioxide pollution (CO2). The reliance of social progress on CO2-producing technologies such as power generation, automobiles, and specialized industrial processes exacerbates the problem. Due to this reliance, it is critical to develop solutions to reduce CO2 emissions from these sources. One such solution is carbon capture and sequestration (CCS), which employs chemical methods to prevent CO2 emissions. The irreversibility of current CCS technology is its primary problem. Chitin, chitosan, and their derivatives, which were recovered from local seafood waste, are studied as reversible CO2 capture materials in this study in an effort to lessen this issue. Polysulfone (PSF) blends were employed to lessen chitosan edema, as chitosan’s hydrophilicity reduces its active sorption surface. Blends with only 20% chitosan have the same high sorption capacity as pure chitosan due to decreased swelling. Hydrolysis was used to boost the chitin sorption abilities. The CO2 sorption data were analyzed using an Intelligent Gravimetric Analyzer (IGA), Fourier-Transform Infrared (FTIR) spectroscopy, and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) spectroscopy. This study reveals that shrimp shells were the best source of chitin. This research led to the creation of eco-friendly, reversible, and reusable carbon sequestration sorbents.

Compounds doi: 10.3390/compounds5020017

Authors: José Muñoz-Espinoza Germán Barriga-González Gino Corsini Sebastián Lagos Andrés Barriga González Nadia Gavilán de Fátima

Laccases are versatile enzymes capable of oxidizing a wide variety of antibiotics. In this study, the mechanism of catalytic oxidation of first-generation tetracyclines, namely, oxytetracycline, tetracycline, and chlortetracycline, by the Melanocarpus albomyces laccase enzyme was investigated using molecular docking and DFT calculations. Molecular docking studies revealed that all three substrates exhibit negative interaction energies, indicating stable enzyme–substrate complexes, with tetracycline and chlortetracycline showing the highest binding affinities. Global reactivity indices obtained by DFT confirmed the high electrophilicity of the enzyme active site, particularly the aminoacidic residues Glu235 and His508, favoring electron transfer from the substrates. In addition, NBO analysis allowed quantification of the energy of hydrogen bonds in enzyme–substrate interactions, evidencing their key role in the stabilization of the complex. Proton transfer analysis suggested two possible mechanisms: (1) a direct concerted transfer and (2) a process mediated by water molecules. The results provide insights into the thermodynamics, electronic structure, and nature of intermolecular interactions governing the oxidation of tetracyclines by the enzyme, highlighting their potential in bioremediation strategies for antibiotic degradation.

Compounds doi: 10.3390/compounds5020016

Authors: Alisha M. O’Brien Kraig A. Wheeler William A. Howard

The dinuclear platinum(IV) compound {Pt(CH3)3}2(μ-I)2(μ-adenine) (abbreviated Pt2ad), obtained by treating cubic [PtIV(CH3)3(μ3-I)]4 with two equivalents of adenine, was isolated and structurally characterized by single crystal X-ray diffraction. The National Cancer Institute Developmental Therapeutics Program’s in vitro sulforhodamine B assays showed Pt2ad to be particularly cytotoxic against the central nervous system cancer cell line SF-539, and the human renal carcinoma cell line RXF-393. Furthermore, Pt2ad displayed some degree of cytotoxicity against non-small cell lung cancer (NCI-H522), colon cancer (HCC-2998, HCT-116, HT29, and SW-620), melanoma (LOX-IMVI, Malme-3M, M14, MDA-MB-435, SK-MEL-28, and UACC-62), ovarian cancer (OVCAR-5), renal carcinoma (A498), and triple negative breast cancer (BT-549, MDA-MB-231, and MDA-MB-468) cells. Although anticancer studies involving some adenine platinum(II) compounds have been reported, this study marks the first assessment of the anticancer activity of an adenine platinum(IV) complex.

Compounds doi: 10.3390/compounds5020015

Authors: Nathalia V. V. de Nunes Sarah K. S. da Silva Marlon B. B. Rodrigues Nidria D. Cruz Augusto S. do Nascimento Ester S. M. Kegles Rafael Beltrame Darci A. Gatto Rafael A. Delucis André L. Missio

The present study aims to evaluate the mechanical properties, colorimetric characteristics, and decay resistance of Pinus elliottii woods treated with oxides synthesized via green chemistry. For this purpose, an aqueous extract from Eucalyptus dunnii leaves was used to synthesize particles based on copper- and zinc-based oxides, as well as a binary oxide system (CuO/ZnO). Sodium polyacrylate was employed as a dispersant, impregnating the oxides into the wood through a horizontal autoclave using a modified Bethell process, assisted by a compressor, applying a pressure of 0.8 MPa for 30 min. The exposure to weathering aging did not significantly alter the mechanical properties of the samples, but it caused the leaching of particles from the treated wood surface, as shown by colorimetric results. Regarding the decay resistance, the copper-based oxide proved to be the most effective treatment against Trametes versicolor (a white-rot fungus), reducing mass loss down to 1.2%. The CuO/ZnO formulation reduced the mass loss caused by Gloeophyllum trabeum to 1.1%, while the zinc oxide showed minimal efficacy. Thus, oxides synthesized via green chemistry using aqueous leaf extracts and mild thermal conditions for synthesis and calcination proved effective in enhancing the wood resistance against biotic deterioration agents.

Compounds doi: 10.3390/compounds5020014

Authors: Petya Emilova Marinova Kristina Dimova Tamahkyarova

Coordination compounds, characterized by the coordination of metal ions with ligands, represent a pivotal area of research in chemistry due to their diverse structures and versatile applications. This review delves into the synthesis, characterization, biological evaluation, and practical applications of these compounds. A variety of synthetic methodologies (traditional solution-based techniques) are discussed to highlight advancements in the field. Investigations into the structural, electronic, and spectral properties of coordination compounds are emphasized to provide insights into their functional attributes. The biological evaluation section focuses on their roles in antimicrobial, anticancer, and enzyme-inhibitory activities, underscoring their potential in therapeutic development. Attention is paid to nanoparticles, which are increasingly used for the treatment of oncological diseases. The metal complexes have been shown to have antibacterial, antifungal, antiviral, antioxidant, and antiproliferative properties. Additionally, the review explores their applications across domains such as catalysis, illustrating their multifaceted utility. By synthesizing recent findings and trends, this article aims to bridge the gap between fundamental chemistry and applied sciences, paving the way for innovative uses of coordination compounds in both biological and industrial contexts.

Compounds doi: 10.3390/compounds5020013

Authors: Gianmarco Bizzarri Girolamo Costanza Ilaria Porroni Maria Elisa Tata

The optimization of elastocaloric cooling systems based on Shape Memory Alloys (SMAs) faces significant challenges in practical implementation. Despite promising thermomechanical properties, the development of efficient and compact cooling devices is hindered by incomplete understanding of strain rate effects on transformation behavior and energy conversion efficiency. While previous research has broadly characterized general SMAs’ thermomechanical behavior, the specific relationship between strain rate and elastocaloric performance in Ni-Ti sheets requires systematic investigation to overcome these barriers. This study investigates the strain rate dependence of Ni-Ti sheets’ properties through systematic mechanical characterization across strain rates ranging from 2.56×10−4s−1 to 6.15×10−3s−1. Commercial Ni-Ti sheets underwent Shape Setting heat treatment and were characterized at eight different deformation levels using a universal testing machine equipped with a 50 kN load cell. Each deformation level was investigated through tests performed at four different crosshead speeds (1–24 mm/min), while monitoring stress-strain behavior and energy parameters. Results suggest distinct rate-dependent patterns in transformation stresses and energy dissipation characteristics across different strain rates. The analysis indicates that mechanical response and transformation behavior vary significantly between lower and higher strain rates, with implications for practical cooling applications. These findings aim to establish guidelines for optimizing elastocaloric performance by identifying suitable operating conditions for specific application requirements, considering factors such as energy conversion efficiency and cycling frequency.

Compounds doi: 10.3390/compounds5020012

Authors: Diogo F. Ribeiro Ana Catarina Severo Maria H. L. Ribeiro

Natural polyphenols, especially the ones in their glycosylated form like hesperidin, rutin, and anthocyanins, are the most abundant phenolic compounds in citric fruits, apples, and red fruits, respectively. They stand out for their high nutraceutical potential, with various reported properties, like antioxidant, anti-inflammatory, anticarcinogenic, and cardioprotective. Nevertheless, these compounds have low bioavailability and are rapidly excreted and released by the organism. Therefore, the main goal of this work was to obtain polyphenols with increased bioactivity by functionalizing biocompounds in fruit juices, namely, orange, apple, and red fruits. This modification was achieved via hesperidinase, an enzyme that catalyzes the hydrolysis of several natural bioactive compounds. Hesperidinase was produced with Penicillium sp. The activity and stability of the produced enzyme, in its free and immobilized form, using the sol–gel method, were assessed, as well as the bioactivity of the bioprocessed juices. Moreover, after immobilizing hesperidinase in sol–gel lens-shaped particles, the activity and operational stability of the bioencapsulates were evaluated by measuring the residual activity over several runs. Using the specific substrate p-NPG, β-D-glucosidase retained 31% of its activity in the second run, 22.6% in the third, and 35% in the fourth. For α-L-rhamnosidase, using the substrate p-NPR, residual activity was 31.1% in both the fourth and fifth runs. In fruit juices, the bioencapsulates exhibited residual activities around 100% in the second run, approximately 81% in the third, and around 90% in the fourth. The antioxidant and anti-inflammatory activities of the bioprocessed juices were evaluated, and an increase in the anti-inflammatory activity was observed when compared with the non-processed juices.

Compounds doi: 10.3390/compounds5020011

Authors: Roman-Malte Richter Daniel James Stauf Anna Lena Rauchel Lutz Ruppach Kevin Bania Annalena Duncker Carsten von Hänisch

Herein, we present hybrid crown ether ligands with siloxane and ethylene oxide units and their coordination with the cations Li+, Na+, Mg2+ and Ca2+. The compounds prepared are (SiMe2O)2(C2H4O)3 (1, TrEGDS = Triethylenglycoldisiloxane) and (SiMe2O)2(C2H4O)4 (2, TeEGDS = Tetraethylenglycoldisiloxane)), as well as the metal complexes [Li(TrEGDS][GaI4] (3), [Na(TeEGDS)][GaI4] (4), [Mg(TrEGDS)][GaI4]2 (5) and [Ca(TeEGDS)][GaI4]2 (6). Single-crystal X-ray diffraction was used to study the prepared complexes and coordination modes in the solid state.

Compounds doi: 10.3390/compounds5020010

Authors: Tatjana Novaković Dejan Pjević Nadica Abazović Zorica Mojović

Alumina is a well-known catalyst and catalyst support. The electrochemical properties of alumina have recently gained attention. The electrochemical response of alumina greatly depends on the type and number of surface groups present in different alumina types. The surfaces of two types of alumina, anhydrous (A) and trihydrate (T) alumina, were modified by copper through an ion-exchange procedure. The samples were characterized by diffuse reflectance UV–Vis spectroscopy. The obtained samples were used as modifiers of carbon paste electrodes. The electrochemical characterization of the samples was performed using cyclic voltammetry and two redox probes. The electrochemical behavior of samples was investigated in the alkaline and neutral media. The electroanalytical performance of the synthesized composites was tested on glutamate and hydrogen peroxide by linear sweep voltammetry. The functionalization of alumina with copper by ion exchange offered a fast and cost-effective procedure for obtaining a composite with enhanced electrochemical properties for sensing biologically important analytes.

Compounds doi: 10.3390/compounds5020009

Authors: Stéphanie Aguiar de Negreiros Matos Silva Ayslan Batista Barros Jessica Maria Teles Souza Rodrigo Ferreira Santiago Evaldo dos Santos Monção Filho Andréa Felinto Moura Alyne Rodrigues de Araújo Durcilene Alves da Silva Mariana Helena Chaves Ana Jérsia Araújo José Delano Barreto Marinho Filho

Secondary metabolites such as flavonoids bring a range of biological properties to natural products, making them potential candidates for the pharmaceutical industry. Piptadenia stipulacea (Benth.) Ducke is well known in Brazil as Jurema Branca, and yet few studies have investigated its biological and phytochemical properties. This study aimed to characterize and evaluate the biological properties of ethanolic extract obtained from the bark of Jurema Branca. Characterization was performed by qualitative phytochemistry, HPLC, and mass spectroscopy. The antibacterial properties were investigated by microdilution method, cytotoxicity by MTT method, biocompatibility testing with human erythrocytes was performed, and antioxidant properties were investigated using DPPH and ABTS radical scavenging. The phytochemical tests demonstrated that rhamnetin and luteolin were the main constituents of the extract. This is the first report of these compounds in this species. The extract presented activity against Staphylococcus aureus (MIC = 500 µg/mL) and demonstrated activity against human colorectal adenocarcinoma (HCT-116), prostate adenocarcinoma (PC-3), and acute myeloid leukemia (HL-60) cell lines with IC50 of 37.96, 37.6, and 27.82 µg/mL, respectively, for this Piptadenia genus. Additionally, the extract presented excellent biocompatibility and antioxidant activity (IC50 = 956.7 and 147.2 µg/mL in DPPH and ABTS methods, respectively). These results are novel for the Piptadenia genus and pave the way for further evaluations regarding the biological importance of this species.

Compounds doi: 10.3390/compounds5020008

Authors: Pedro Fernandes

FOSs are short-chain fructose-based oligosaccharides with notable functional and health benefits. Naturally present in various fruits and vegetables, FOSs are primarily produced enzymatically or microbially from sucrose or long-chain fructans, namely, inulin. Enzymes such as fructosyltransferase, β-fructofuranosidase, and endoinulinase are typically involved in its production. The chemical structure of FOSs consists of an assembly of fructose residues combined with a glucose unit. The increasing consumer demand for healthy foods has driven the widespread use of FOSs in the functional food industry. Thus, FOSs have been incorporated into dairy products, beverages, snacks, and pet foods. Beyond food and feed applications, FOSs serve as a low-calorie sweetener for and are used in dietary supplements and pharmaceuticals. As a prebiotic, they enhance gut health by promoting the growth of beneficial bacteria, aid digestion, improve mineral absorption, and help regulate cholesterol and triglyceride levels. Generally recognized as safe (GRAS) and approved by global regulatory agencies, FOSs are a valuable ingredient for both food and health applications. This review provides an updated perspective on the natural sources and occurrence of FOSs, their structures, and physicochemical and physiological features, with some focus on and a critical assessment of their potential health benefits. Moreover, FOS production methods are concisely addressed, and forthcoming developments involving FOSs are suggested.

Compounds doi: 10.3390/compounds5010007

Authors: Luis Craco Sabrina S. Carara

Using DFT+DMFT, we show the importance of spin-orbit coupling together with multi-orbital interactions in prescribing the reconstructed electronic state of the cubic CsPbI3 crystal. Considering realistic Coulomb parameter values and Pb-spin-orbit interaction, we uncover relevant key features in the one-particle spectral functions for the Pb-6p and I-5p orbitals of semiconducting CsPbI3 bulk crystal and the role played by p and n doping relevant for band-selective metallicity and current-voltage characteristics. The implication of our study for cubic CsPbI3 is expected to be an important step to understanding the electronic structure of pure and doped broadband solar cell-based memristor materials for neuromorphic computing.

Compounds doi: 10.3390/compounds5010006

Authors: Yuanyuan Sun Le Yu Yichen Wang Nian-Tzu Suen

The cocrystallization technique has been widely applied in the fields of energetic materials (EMs) to settle the inherent trade-off between high energy and low sensitivity in current high-energy molecules. Despite its widespread application, the mechanistic understanding of cocrystals growing from solutions remains largely underexplored. This paper presents a mechanistic model grounded in the spiral growth mechanism to predict the crystal morphologies of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and 7H-trifurazano [3,4-b:3′,4′-f:3″,4″-d]azepine (TFAZ) cocrystals. In this model, it was assumed that CL-20 and TFAZ molecules incorporated into the crystal lattice simultaneously from solution as preformed growth units. The binding energies between the CL-20 molecule and TFAZ molecule were calculated to determine the most potential growth units. The predicted morphologies closely align with the experimental determinations supporting the model’s validity. Furthermore, the study found that the crystal habits were significantly influenced by the choice of solvents, due to variations in interfacial energetics affecting the growth process.

Compounds doi: 10.3390/compounds5010005

Authors: Juan C. Mejuto

Compounds has existed as a scientific publication in the field of chemistry for five years now [...]

Compounds doi: 10.3390/compounds5010004

Authors: Norma Mallegni Francesca Cicogna Elisa Passaglia Vito Gigante Maria-Beatrice Coltelli Serena Coiai

The depletion of fossil fuels and environmental concerns have driven the development of sustainable materials, including bio-based and biodegradable plastics, as alternatives to conventional plastics. Although these plastics aid in waste management and climate change mitigation, their vulnerability to oxidative degradation impacts their longevity, durability, and performance. Natural antioxidants such as tocopherols, flavonoids, and tannins, extracted from plants or agri-food waste, present a sustainable alternative to synthetic stabilizers by enhancing the oxidative thermal stability of polymers like poly(lactic acid) (PLA), poly(butylene succinate) (PBS), poly(butylene succinate-adipate) (PBSA), poly(butylene adipate-co-terephthalate) (PBAT), poly(hydroxyalkanoate) (PHA), and starch-based materials. This review highlights recent advances in bio-based plastics stabilized with natural antioxidants, their mechanisms of action, and their role in improving material properties for applications like packaging. Additionally, it explores their impact on recycling processes, advancements in composite production techniques, and future research directions. Bioplastics can achieve enhanced performance, reduce waste, and support a circular economy by incorporating natural antioxidants.

Compounds doi: 10.3390/compounds5010003

Authors: Eleni Kakouri Dimitra Daferera Aimilia Nalbanti Panayiotis Trigas Petros A. Tarantilis

The genus Hypericum (Hypericaceae), comprising approximately 500 taxa classified into 22 sections, has remained largely unexplored in terms of its chemical composition, with existing studies on a limited number of species revealing significant chemical polymorphism. This study investigates the volatile profiles of four Hypericum species (H. rumeliacum subsp. apollinis, H. vesiculosum, H. delphicum, and H. olympicum) through GC-MS analysis. Hypericum rumeliacum subsp. apollinis, collected from Mt. Parnassos, exhibited a high abundance of sesquiterpenes hydrocarbons (32.5%) and oxygenated sesquiterpenes (29.7%). Hypericum vesiculosum collected from Mt. Chelmos was rich in oxygenated monoterpenes (33.5%), followed by benzyl derivatives (25.9%). Hypericum delphicum and H. olympicum, collected from the island of Evvia, showed a predominance of alkanes (35.8%) and oxygenated sesquiterpenes (31.9%) in H. delphicum and sesquiterpenes hydrocarbons (41.2%) and oxygenated sesquiterpenes (29.9%) in H. olympicum. Our findings provide new data on the volatile profile of H. vesiculosum and enhance existing information on other species, highlighting notable chemical diversity within the genus Hypericum.

Compounds doi: 10.3390/compounds5010002

Authors: Martha Mantiniotou Vassilis Athanasiadis Dimitrios Kalompatsios Eleni Bozinou Stavros I. Lalas

Plant-derived secondary metabolites such as triterpenes and triterpenoids are present in a wide range of plant species. These compounds are particularly attractive due to their extensive range of biological properties and potential applications as intermediates in the synthesis of novel pharmacologically promising medications. Saponins, which are glycosylated triterpenoids found in nature, exhibit the same properties. At this point, the effectiveness of saponins as an anti-inflammatory medication has been verified. This review article examines the primary connections between immune responses and anti-inflammatory activity, focusing specifically on the correlation between triterpenes and triterpenoids. These connections have been investigated in various cell models, as well as in vitro and in vivo studies. The present research provides a comprehensive overview of the current understanding of the therapeutic capabilities of triterpenes and triterpenoids in immune and inflammatory processes. It also highlights emerging standards and their potential utilization in pharmaceutical and clinical settings.

Compounds doi: 10.3390/compounds5010001

Authors: Pedrita A. Sampaio Emanuella C. V. Pereira Pedro G. S. Sá José Marcos T. Alencar Filho Leslie R. M. Ferraz Rodolfo H. V. Nishimura Aline S. Ferreira Pedro J. Rolim Neto Evando S. Araújo Larissa A. Rolim

Metal–organic frameworks (MOFs) are also known as porous coordination polymers. This kind of material is constructed with inorganic nodes (metal ions or clusters) with organic linkers and has emerged as a promising class of materials with several unique properties. Well-known applications of MOFs include their use as gas storage and in separation, catalysis, carbon dioxide capture, sensing, slender film gadgets, photodynamic therapy, malignancy biomarkers, treatment, and biomedical imaging. Over the past 15 years, an increasing amount of research has been directed to MOFs due to their advanced applications in fuel cells, supercapacitors, catalytic conversions, and drug delivery systems. Various synthesis methods have been proposed to achieve MOFs with nanometric size and increased surface area, controlled surface topology, and chemical activity for industrial use. In this context, the pharmaceutical industry has been watching the accelerated development of these materials with great attention. Thus, the objective of this work is to study the synthesis, characterization, and toxicity of MOFs as potential technological excipients for the development of drug carriers. This work highlights the use of MOFs not only as delivery systems (DDSs) but also in advanced diagnostics and therapies, such as photodynamic therapy and targeted delivery to tumors. Bibliometric analyses showed a growing interest in the topic, emphasizing its contemporary relevance.

Compounds doi: 10.3390/compounds4040044

Authors: José C. J. M. D. S. Menezes Vinícius R. Campos

Natural alkylated hydroxy cinnamates (AHCs) isolated from medicinal plants and the thereby designed and synthesized cinnamides are derivatives of hydroxy cinnamic acids such as p-coumaric, sinapic, ferulic, and caffeic acids, which are naturally derived from human dietary sources. The pharmacological properties displayed by AHCs based on their inherent structure range include antioxidant, antimicrobial, antiplasmodial, anti-tyrosinase, Alzheimer’s and Parkinson’s disease therapy, anticancer therapy, metabolic disease therapy, and biopesticides, which have not been reviewed together. Based on their inherent antioxidant, antimicrobial, and UV absorption and their structure–activity relationships, these cinnamyl esters and amides can be used for food preservation in emulsions and oils, as sun-protective components of skin care formulations, and in many other multifunctional applications. In conclusion, the fine-tuning of the structural features such as the type of hydroxy cinnamic acid used, the length of alkyl chains for variable lipophilicity, conversion from cinnamic to propanoic for antioxidants, the increase in methoxy or the change to amino groups to increase the molar absorption coefficient and loss of absorption values, the substitution by halides or amino groups for potent biopesticides, and conversion from esters to amide bonds leads to different AHCs for biomedical, cosmetic, and agriculture applications as an emerging field of investigation that can overall provide natural, safe, biodegradable, and sustainable molecules.

Compounds doi: 10.3390/compounds4040043

Authors: Raquel Neves Maria H. L. Ribeiro

This study evaluates the feasibility and effectiveness of using immobilized pectinase enzymes for juice processing to reduce cloudiness while preserving nutritional and bioactive properties. The research is driven by the increasing demand for innovative food products that offer enhanced functionality and health benefits. It focuses on the development and application of immobilized biocatalysts in bioprocessing, specifically using pectinase encapsulated in a sol–gel matrix. Reaction parameters for the interaction between immobilized pectinase and its primary substrate, pectin, were optimized through systematic experimentation. Optimal conditions were established, achieving enhanced enzyme activity and stability with 0.15 g of lens-shaped capsules containing 10.0 mg/mL pectinase in 24-well microplates as microreactors. Kinetic studies indicated improved substrate affinity after immobilization (Km = 0.115 mg/mL), particularly when magnetized (Kmi = 0.041 mg/mL). Operational stability and reusability assessments demonstrated potential for extended use with magnetized pectinase capsules retaining higher residual activity after a fourth reuse cycle (155% > 75%). The application of immobilized pectinase in processing peach nectar successfully reduced cloudiness and increased the release of bioactive compounds, enhancing antioxidant and anti-inflammatory activities, as evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and the albumin method, respectively. In vitro digestion studies revealed dynamic activity profile changes, highlighting the impact of juice bioprocessing on bioavailability.

Compounds doi: 10.3390/compounds4040042

Authors: Helena Cristina Vasconcelos Henrique Carrêlo Telmo Eleutério Maria Gabriela Meirelles Reşit Özmenteş Roberto Amorim

This study investigates the rheological behavior of cellulose microfiber suspensions derived from kahili ginger stems (Hedychium gardnerianum), an invasive species, in two adhesive matrices: a commercial water-based adhesive (Coplaseal®) and a casein-based adhesive made from non-food-grade milk, referred to as K and S samples, respectively. Rheological analyses were performed using oscillatory and rotational shear tests conducted at 25 °C, 50 °C, and 75 °C to assess the materials’ viscoelastic properties more comprehensively. Oscillatory tests across a frequency range of 1–100 rad/s assessed the storage modulus (G′) and loss modulus (G″), while rotational shear tests evaluated apparent viscosity and shear stress across shear rates from 0.1 to 1000 s−1. Fiber-free samples consistently showed lower moduli than fiber-containing samples at all frequencies. The incorporation of fibers increased the dynamic moduli in both K and S samples, with a quasi-plateau observed at lower frequencies, suggesting solid-like behavior. This trend was consistent in all tested temperatures. As frequencies increased, the fiber network was disrupted, transitioning the samples to fluid-like behavior, with a marked increase in G′ and G″. This transition was more pronounced in K samples, especially above 10 rad/s at 25 °C and 50 °C, but less evident at 75 °C. This shift from solid-like to fluid-like behavior reflects the transition from percolation effects at low frequencies to matrix-dominated responses at high frequencies. In contrast, S samples displayed a wider frequency range for the quasi-plateau, with less pronounced moduli changes at higher frequencies. At 75 °C, the moduli of fiber-containing and fiber-free S samples nearly converged at higher frequencies, indicating similar effects of the fiber and matrix components. Both fiber-reinforced and non-reinforced suspensions exhibited pseudoplastic (shear-thinning) behavior. Fiber-containing samples exhibited higher initial viscosity, with K samples displaying greater differences between fiber-reinforced and non-reinforced systems compared to S samples, where the gap was narrower. Interestingly, S samples exhibited overall higher viscosity than K samples, implying a reduced influence of fibers on the viscosity in the S matrix. This preliminary study highlights the complex interactions between cellulosic fiber networks, adhesive matrices, and rheological conditions. The findings provide a foundation for optimizing the development of sustainable biocomposites, particularly in applications requiring precise tuning of rheological properties.

Compounds doi: 10.3390/compounds4040041

Authors: Maha Sharaf Mohamed S. Atrees Gehad M. Saleh Hamed I. Mira Shunsuke Tanaka

Advancements in membrane separation techniques will expand the applications and requirements for highly specialized, inventive, efficient, and resistant separation materials. The selective separation of rare earth elements (REEs) is one of the expanding applications of membrane-based techniques, as their use is becoming more widespread. Membrane techniques are becoming increasingly desired as environmentally friendly, straightforward methods for treating wastewater and separating metals. For the separation of REEs, an innovative impregnated mixed-matrix membrane (IMMM) technique was developed in this study. It provides a selective, efficient, and reusable method that is suitable for industrial applications. Terbium was selectively adsorbed from other REEs using organophosphorus IMMM with a loading capacity of 113.2 mg/g in 3 h and was reused three times without destroying the initial membrane. Solvent impregnation is thought to offer specific chelation sites that are selective for terbium separation.

Compounds doi: 10.3390/compounds4040040

Authors: Alessandra Ceci Girolamo Costanza Maria Elisa Tata

Over the past few years, researchers have developed the alloy Al-Mg-Zn(-Cu), a new aluminum alloy based on the technique of ‘crossover alloying’. The main strengthening phase of this novel alloy is T-Mg32(Al, X)49(X is Zn and Cu) after ageing and hardening. This alloy system has exceptional strength and corrosion resistance, making it a promising candidate for applications in fields like automotive, marine, aerospace, and many others. In this work, the research progress of the Al-Mg-Zn(-Cu) alloy based on microstructure control, composition, design, and properties has been reviewed. Future directions for the research of this alloy are highlighted, too. In this work, crossover alloys are presented as a potential novel class of Al alloys implicating a pioneering design approach, with particular emphasis on the aeronautical and aerospace field in which radiation resistance results are one hundred times higher than traditional precipitation hardening alloys.

Compounds doi: 10.3390/compounds4040039

Authors: Tatiana V. Safronova Peter D. Laptin Alexandra I. Zybina Xiaoling Liao Tatiana B. Shatalova Olga V. Boytsova Dinara R. Khayrutdinova Marat M. Akhmedov Zichen Xu Irina V. Kolesnik Maksim R. Kaimonov Olga T. Gavlina Muslim R. Akhmedov

Powders with a phase composition including syngenite (K2Ca(SO4)2·H2O) and/or calcium sulfate dihydrate (gypsum, CaSO4·2H2O) were synthesized from the powder of calcium carbonate (CaCO3) and water solutions of potassium hydrosulfate (KHSO4) of various concentrations (0.5 M, 1 M, and 2 M). A molar ratio of starting salts, KHSO4/CaCO3 = 2, was used to provide the formation of syngenite (K2Ca(SO4)2·H2O). But when using a 0.5 M water solution of potassium hydrosulfate (KHSO4), the phase composition of the synthesized powder was presented by calcium sulfate dihydrate (gypsum, CaSO4·2H2O). When using 1 M and 2 M water solutions of potassium hydrosulfate (KHSO4), the syngenite (K2Ca(SO4)2·H2O) was found as the predominant phase in synthesized powders. According to estimations made from thermal analysis data, powders synthesized using 1.0 M and 2.0 M water solutions of potassium hydrosulfate (KHSO4) contained no more than 7.9 and 1.9 mass % of calcium sulfate dihydrate (gypsum, CaSO4·2H2O), respectively. The phase composition of products isolated from mother liquors via water evaporation consisted of syngenite (K2Ca(SO4)2·H2O) and potassium sulfate (arcanite, K2SO4). Synthesized powders can be used in preparation of biocompatible bioresorbable materials with phase compositions in the K2O-CaO-SO3-H2O system; as matrix of thermo- or photo-luminescent materials; as components reducing the setting time and increasing the strength of sulfate cements; in the fertilizing industry; and also as components of Martian regolith simulants.

Compounds doi: 10.3390/compounds4040038

Authors: Partha Sarathi Bera Yafia Kousin Mirza Tarunika Sachdeva Milan Bera

The smallest strained, saturated N-heterocycles, such as aziridine, can be a valuable building block in synthetic organic chemistry. Ring-opening reactions with various nucleophiles could be the most important strategy to synthesize various value-added molecular entities. Therefore, regioselective ring-opening reactions of aziridines with various heteroatomic nucleophiles and carbon nucleophiles establish a useful synthetic methodology to synthesize biologically relevant β-functionalized alkylamines. The regio-selective ring-opening of aziridines is highly dependent on the substrate combination, and stereochemical control is challenging for Lewis acid-promoted reactions. Therefore, the development of a robust, catalytic ring-opening process that assists in the accurate prediction of regioselectivity and stereochemistry is highly desirable. Consequently, a large number of publications detailing distinct methods for aziridine ring-opening reactions can be found in the literature. In this review, we discuss several transition metal catalyzed cross-coupling reaction protocols for the ring opening of substituted aziridines with various carbon nucleophiles.

Compounds doi: 10.3390/compounds4040037

Authors: José C. J. M. D. S. Menezes Vinícius R. Campos

This review discusses the development and applications of bioconjugates derived from natural hydroxycinnamic acids (HCA), such as coumaric, sinapic, ferulic, and caffeic acids, combined with various biomaterials. These bioconjugates offer a range of benefits including antioxidant properties, UV protection, customized hydrophilic–lipophilic balance, improved safety, solubility, emolliency, biocompatibility, biodegradability, and targeted delivery for biomedical, cosmetic, and food applications. The increasing demand for natural products in the biomedical, cosmetic, and food industries has led to the exploration of these hydroxycinnamic acids and their derivatives. We discuss the synthesis and modification of hydroxycinnamic acids with biomaterials such as ω-hydroxy fatty acids, castor and lesquerella oils, glycerol, isosorbides, and synthetic polyethylene glycol to form functional phenolipids for biomedical, sunscreen, and skincare applications. Encapsulation techniques with β-cyclodextrins and modification of polymeric supports like polysaccharides and starch are discussed for enhancing bioavailability and solubility and targeted delivery. The fine-tuned development of bioconjugates from hydroxycinnamic acids using glycerol to modify the hydrophilic–lipophilic balance, substitution by water-soluble carboxylic acid groups, vegetable oil-based phenolipids, polysaccharides, and PEGylation provide enhanced dual functionalities and offer a promising avenue for creating effective products across various applications.

Compounds doi: 10.3390/compounds4040036

Authors: Marianna Portaccio Ines Delfino Giovanni Maria Gaeta Umberto Romeo Maria Lepore

In recent years, the femtosecond laser ablation of hard dental tissues has stimulated great interest in preparing accurate and reproducible dental cavities. Many studies on the changes induced in the surface morphology, structure, and composition of human teeth have been performed using various advanced experimental techniques. Vibrational spectroscopies such as Fourier transform infrared (FT-IR) and Raman spectroscopy have been adopted for obtaining precise information about changes induced by femtosecond laser ablation in human teeth. Their two main components, dentin and enamel, have been carefully investigated. The analysis of the vibrational spectra has allowed for the identification of the optimal working parameters for efficient laser ablation processes. In the present review, a brief description of the abovementioned vibrational techniques is reported, and the principal results obtained by these two vibrational spectroscopies in the study of femtosecond laser ablated teeth are summarized and analyzed.

Compounds doi: 10.3390/compounds4030035

Authors: Weiguang Zhou Haobin Wei Yangge Zhu Yufeng Long Yanfei Chen Yuesheng Gao

To investigate how hydrodynamic cavitation (HC) affects the adsorption of sodium oleate (NaOl) on diaspore and kaolinite surfaces, a comparative study on NaOl adsorption was conducted under different conditions. The flotation and separation of the minerals were also examined with and without HC pretreatment of NaOl. The results show that short-term HC pretreatment of NaOl solutions did not induce a measurable change in the chemical structure of NaOl, but produced micro-nanobubbles (MNBs) and resulted in decreases in the surface tension and viscosity of liquids. When MNBs interacted with minerals, their anchor on solids could affect the contact angles, zeta potentials, and surface NaOl adsorption toward minerals. At low NaOl concentrations, the presence of MNBs reduced the NaOl adsorption capacity and particles’ zeta potential while increasing the minerals’ contact angle. At higher NaOl concentrations, the presence of MNBs promoted NaOl adsorption, further increased the minerals’ contact angle, and further decreases the particles’ zeta potential. Additionally, the flotation and separation of minerals can be enhanced at low NaOl concentrations, largely due to the enhanced bubble mineralization through the selective surface-anchoring of MNBs on diaspore. However, the separation efficiency might deteriorate at high NaOl concentrations, though the presence of MNBs amplified the divergences in minerals’ surface wettability and zeta potentials.