Terpenes represent a structurally diverse class of natural compounds with increasing scientific interest due to their potential anti-inflammatory properties. This study investigates the in silico binding behavior of six plant-derived terpenes—α-pinene, β-pinene, menthol, camphor, limonene, and linalool—against four key enzymes in the arachidonic acid (AA) metabolic pathway: cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and phospholipase A2 (PLA₂). AA serves as a reference for binding energy comparison. Blind rigid-body molecular docking is performed using AutoDock 4.2 and the Lamarckian Genetic Algorithm, with 100 runs per ligand–enzyme pair and the energy-based selection of optimal poses. The analysis includes binding energy (ΔG), inhibition constants (Ki), root-mean-square deviation (RMSD), and residue-level interactions. Several terpenes exhibit favorable binding energies and inhibition constants across the evaluated enzymes. For COX-1 and COX-2, menthol and camphor show low Ki values, indicating stable binding. Menthol and limonene also show the strongest affinities for PLA₂, exceeding AA. The focus is on compounds with potential to modulate arachidonic acid metabolism. In this context, β-pinene engages the catalytic site of PLA₂, linalool forms multiple contacts within key regions of 5-LOX, and menthol, α-pinene, and β-pinene align with functionally important regions in both COX isoforms. These targeted interactions suggest that the highlighted compounds may selectively interfere with enzymatic activity in inflammation-related pathways. By modulating key steps in AA metabolism, these terpenes may influence the biosynthesis of pro-inflammatory mediators, offering a promising avenue for the development of safer, plant-derived anti-inflammatory agents. The findings lay the groundwork for further experimental validation and the structure-based optimization of terpene-derived modulators.

Isatin derivatives have been at the forefront of pharmaceutical research, displaying a wide range of biological activities, including antioxidant, antimicrobial, and anticancer properties. In this study, twelve isatin-pyridine Schiff bases were evaluated using density functional theory (DFT) methods to examine the influence of pyridyl ring orientation (2-, 3-, and 4-aminopyridine) and C6-halogen substitution (F, Cl, Br) on electronic structure and reactivity. Frontier molecular orbitals and global reactivity descriptors were calculated to evaluate donor–acceptor properties, charge-transfer ability, and electronic stability. The 2-aminopyridine derivatives display the highest occupied molecular orbital (HOMO) energies, lowest unoccupied molecular orbital (LUMO) energies, and smallest energy gaps. Chlorine- and bromine-substituted derivatives show enhanced electrophilicity, electronegativity, and ∆N _max , while fluorine has minimal influence. DFT analysis reveals that 6-chloro-3-(2-pyridylimine)-indole-2-one and 6-bromo-3-(2-pyridylimine)-indole-2-one are the most promising candidates, as their electronic features are consistent with enhanced biological activity. These findings provide a basis for the rational design of next-generation isatin-Schiff bases with optimized reactivity and improved biological potential.

Bexarotene is a clinically approved anticancer agent belonging to the retinoid class. Integrating the retinoid scaffold with a hydrazone moiety represents a promising strategy for modulating electronic properties relevant to receptor binding and desired biological activity. However, the electronic effects of halogen substitution within the retinoid–hydrazone framework have not been systematically studied. To address this gap, this study investigates the effects of substituent position, halogen type, and halogen load on the electronic structure and reactivity of a series of bexarotene-derived hydrazones. Density functional theory (DFT) calculations were carried out for six bexarotene–hydrazone derivatives (V1–V6), enabling the evaluation of frontier molecular orbital energies and global reactivity descriptors. In the series, V2 emerged as the strongest electron acceptor, demonstrating the highest electronegativity, the largest electrophilicity index, and the lowest unoccupied molecular orbital (LUMO) energy. The para -bromo analogue V4 displayed a similarly narrow highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap, although it demonstrated more donor-like behavior. The dichloro derivative V3, on the other hand, had the widest energy gap and the highest hardness and was recognized as the most electronically stable derivative. The ortho -chloro derivative V6 showed strong similarity to V3 in several descriptors, showing that substituent position can rival the number of halogens in determining reactivity. Overall, these electronic patterns provide a basis for future drug design, demonstrating how targeted substituent modification within the bexarotene–hydrazone scaffold can guide the development of new molecules with more favorable physicochemical properties.

IR and UV-VIS spectroscopic analysis of a new compound: N-[1-(4-hydroxyphenyl) aminoethilyden]-4-[1-(3,5,5,8,8-pentamethyl-6,7-dihydronaphtalen-2-yl)-ethenyl] phenylcarbohydrazide