Compounds, Volume 5, Issue 3 (September 2025) – 10 articles

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. Full article

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. Full article

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–mass spectrometry (GC–MS), 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. Full article

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. Full article

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. Full article

An important property of arylboronic acids, particularly when considering their use in medicinal chemistry, is their pK_a in aqueous solution. The results of computational determination of absolute pK_as 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 pK_a 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 pK_as of arylboronic acids is proposed and applied to a set of recently synthesized arylboronic acids, yielding consistent results. Full article

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. Full article

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. Full article

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. Full article

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. Full article