Pyridoxal–S-methyl-isothiosemicarbazone (PLITSC) is a member of an important group of ligands characterized by different complexation modes to various transition metals. In this contribution, a new complex containing two differently protonated PLITSC ligands ([Fe(PLITSC–H)(PLITSC)]SO₄)∙2.5H₂O was obtained. The crystal structure was solved by the X-ray analysis and used further for the optimization at B3LYP/6-311++G(d,p)(H,C,N,O,S)/def2-TZVP(Fe) level of theory. Changes in the interaction strength and bond distance due to protonation were observed upon examination by the Quantum Theory of Atoms in Molecules. The protein binding affinity of [Fe(PLITSC–H)(PLITSC)]SO₄ towards transport proteins (Bovine Serum Albumin (BSA) and Human Serum Albumin (HSA)) was investigated by the spectrofluorimetric titration and molecular docking. The interactions with the active pocket containing fluorescent amino acids were examined in detail, which explained the fluorescence quenching. The interactions between complex and DNA were followed by the ethidium-bromide displacement titration and molecular docking. The binding along the minor groove was the dominant process involving complex in the proximity of DNA.

Grape stems are an abundant by-product of winemaking and a promising source of phenolic antioxidants representing an underutilized biomass within the circular economy. Seven Vitis vinifera L. cultivars were analysed by HPLC DAD, with Merlot (Me), Cabernet Sauvignon (CS) and Italian Riesling (IR) identified as the richest sources. This comparative screening provided the basis for a multi-index optimization of extraction. A 2³ full factorial design (ethanol 30–60% v/v; 30–80 min; 25–65 °C) was used for optimization. The optimal green conditions—60% ethanol, 80 min, 65 °C—yielded 1.860 mg/g CA, 1.098 mg/g Q-gluc and 0.409 mg/g Q-glc, with the Merlot stems showing the highest extraction efficiency and Merlot consistently outperforming the other varieties. Kinetic modeling using an unsteady state diffusion model showed excellent agreement (R² ≈ 0.99, RMS < 2%), suggesting a leaching-diffusion mechanism. The thermodynamic parameters confirmed an endothermic, spontaneous and irreversible process with ΔH° between 19.5 and 36.6 kJ/mol, ΔS° between 69.1 and 131.6 J/molK and ΔG° between −1.1 and −9.2 kJ/mol, depending on the compound and grape stem variety. This study shows that grape stems can be efficiently utilised as a sustainable source of phenolic antioxidants, with potential applications in the production of functional foods and dietary supplements. This integration highlights the novelty of the study and supports the valorization of grape stems in the framework of sustainability and the circular economy.

Vanadium complexes have gained considerable attention as biologically active compounds. In this contribution, three previously reported dioxovanadium(V) complexes with pyridoxal semicarbazone, thiosemicarbazone, and S-methyl-iso-thiosemicarbazone ligands are theoretically examined. The intermolecular stabilization interactions within crystallographic structures were investigated by Hirshfeld surface analysis. These experimental structures were optimized at the B3LYP-D3BJ/6-311++G(d,p)(H,C,N,O,S)/def2-TZVP(V) level of theory, and crystallographic and optimized bond lengths and angles were compared. High correlation coefficients and low mean absolute errors between these two data sets proved that the selected level of theory was appropriate for the description of the system. The changes in structures and stability were examined by adding explicit solvent molecules. The Quantum Theory of Atoms in Molecules (QTAIM) was employed to analyze the intramolecular interactions with special emphasis on the effect of substituents. A good correlation between electron density/Laplacian and interatomic distance was found. Through molecular docking simulations towards Bovine Serum Albumin (BSA), the binding affinity of complexes was further investigated. The spontaneity of binding in the active position of BSA was shown. Further experimental studies on this class of compounds are advised.

The oxidative degradation of anthocyanins in red wine was investigated under controlled conditions using hydroxyl radicals generated in the presence of Cu (II) as a catalyst. A full factorial experimental design with 23 replicates was used to evaluate the effects of hydrogen peroxide concentration, catalyst dosage, and reaction temperature on anthocyanin degradation over a fixed time. Statistical analysis (ANOVA and multiple regression) showed that all three variables and the main interactions significantly affected anthocyanin loss, with temperature identified as the most influential factor. The combined effects were described by a first-order polynomial model. The activation energies for degradation ranged from 56.62 kJ/mol (cyanidin-3-O-glucoside) to 40.58 kJ/mol (peonidin-3-O-glucoside acetate). Increasing the temperature from 30 °C to 40 °C accelerated the degradation kinetics, almost doubled the rate constants and shortened the half-life of the pigments. At 40 °C, the half-lives ranged from 62.3 min to 154.0 min, depending on the anthocyanin structure. These results contribute to a deeper understanding of the stability of anthocyanins in red wine under oxidative stress and provide insights into the chemical behavior of derived pigments. The results are of practical importance for both oenology and viticulture and support efforts to improve the color stability of wine and extend the shelf life of grape-based products.

This study focused on optimizing key extraction parameters (ethanol concentration, temperature, and time) to enhance the extraction of hydroxycinnamic acids from A. graveolens leaves, applying a replicated 2³ full factorial design. The experimental results demonstrated that extraction conditions significantly influenced the yield of hydroxycinnamic acids. The optimum conditions were 50% ethanol for 80 min at 50 °C, yielding 103.75 µg/g of chlorogenic acid (ChA), 6.05 µg/g of ferulic acid (FA), and 2.19 µg/g of sinapic acid (SA). Therefore, the extract obtained with 50% ethanol showed the highest levels of polyphenols, flavonoids, and antioxidant potential, highlighting its suitability for use in both food-related products and pharmaceutical formulations. Additionally, the applicability of different mathematical models (unsteady-state diffusion, parabolic diffusion, and power law models, as well as Ponomaryov’s and Elovich’s equations) to describe and better understand the kinetics of hydroxycinnamic acid extraction from dill leaves was evaluated. The fit of each kinetic model to the experimental data was assessed using the root mean square error and the coefficient of determination. Among the five kinetic models, the unsteady-state diffusion model and Ponomaryov’s equation provided the best fit, exhibiting the highest accuracy. The activation energy for the extraction process was determined to be 5.85, 6.46, and 7.59 kJ/mol for ChA, FA, and SA, respectively. The extraction of hydroxycinnamic acids from dill leaves was found to be endothermic, irreversible, and spontaneous.

The effects of temperature, time, and solvent concentration on the yield of bioactive compounds (BCs) with cytotoxic activity against three cell lines (Hep2c, RD, and L2OB) from Erica carnea L., as well as their influence on kinetic and thermodynamic parameters (enthalpy, entropy, and free energy), were investigated. The extract obtained at 30% ethanol, 50 °C, and 80 min showed the highest cytotoxic activity with IC₅₀ values of 14.29, 13.93, and 22.23 µg/mL, respectively. The kinetics of BC extraction with cytotoxic activity was better described by the unsteady-state diffusion model compared to the Ponomarev model. The activation energy obtained was in the range of Ea = (4.92–26.57) kJ/mol. The thermodynamic parameters under transition theory at 50 °C were ∆S* = (−220.22)–(−285.15) J/Kmol, ∆H* = (2.24–23.88) kJ/mol, and ∆G* = (94.34–96.30) kJ/mol, indicating that the extraction of BCs with cytotoxic activity against the three cell lines is an irreversible and endothermic process. In addition to cytotoxic activity, the extracts demonstrated strong antioxidant activity (e.g., DPPH IC₅₀ = 16.55 µg/mL) and antibacterial activity against multiple bacterial strains. Five antioxidant assays were applied, along with tests against eight bacterial strains for antibacterial activity. These findings suggest that Erica carnea L. is a promising natural source of multifunctional bioactive compounds with therapeutic potential.