V. O. Imieje

Schiff bases are synthesized through condensation reactions between primary amines and aldehydes or ketones. They have been identified as promising lead compounds for drug design and development. The study aims to synthesize, characterize, and assess the physicochemical and pharmacological properties of Schiff base derivatives. Para-aminophenol (3.0 g) was reacted with benzaldehyde (3.0 g), 4-methoxybenzaldehyde (3.2 g), 3-OH-4-methoxybenzaldehyde (4 g), methylene-dioxybenzaldehyde (4 g), 4- chlorobenzaldehyde (4 g), 4-nitrobenzaldehyde (4 g), 3,4-dimethyl-aminobenzaldehyde (4 g), and cinnamaldehyde (3.3 g). The reaction was microwaved at 140 W (20 % intensity) after 3-5 drops of glacial acetic acid for 5 minutes. The mixture was cooled to room temperature, then filtered and recrystallized using either methanol or ethanol to produce samples BS1 to BS8. The reaction was monitored via TLC. Elemental composition was confirmed with spectroscopic analysis. Antimicrobial activity was evaluated using the agar diffusion method, toxicity was determined following the Lorke method, and analgesic properties were assessed using the hot plate model. In silico analyses were also performed on all products to determine their potential protein-ligand binding interactions. Antimicrobial screening indicated that BS1, BS2, BS5, BS6, and BS8 exhibited moderate inhibitory activity against Escherichia coli, Staphylococcus aureus, and Candida albicans. BS3 showed zones of inhibition for E. coli and S. aureus, 14 mm and 13 mm, respectively. The MIC was determined to be 62.5 µg/ml, while the MBC for BS1 and BS2 was 125 µg/ml. Acute toxicity studies revealed an LD₅₀ of 316 to 1265 mg/kg. Analgesic evaluation demonstrated promising activity when compared to pethidine. In silico analyses showed BS3 and BS7 favorable binding affinities with cyclooxygenase-1 (COX-1) and COX-2 enzymes (-8.62 and -8.49 kcal/mol, respectively). The findings suggest that these derivatives have potential therapeutic applications, particularly as analgesics and antimicrobial agents, with further optimization of their structural efficiency, pharmacological efficacy, pharmacokinetic parameters, and safety