Compounds, Volume 5, Issue 2 (June 2025) – 10 articles

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. Full article

The dinuclear platinum(IV) compound {Pt(CH₃)₃}₂(μ-I)₂(μ-adenine) (abbreviated Pt₂ad), obtained by treating cubic [Pt^IV(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. Full article

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. Full article

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. Full article

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 $2.56\times {10}^{-4}{\mathrm{s}}^{-1}$ to $6.15\times {10}^{-3}{\mathrm{s}}^{-1}$. 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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article