Microwave-Assisted Synthesis, In Vivo Anti-Inflammatory and In Vitro Anti-Oxidant Activities, and Molecular Docking Study of New Substituted Schiff Base Derivatives

In view of considerable interest in the design and synthesis of new heterocyclic compounds with promising biological activities for medical and biological applications, a series of eight imine derivatives have been synthesized through microwave-assisted Schiff base formation by reacting 2-(4-methoxyphenyl)acetohydrazide (3) and 4-amino-3-(4-methoxybenzyl)-1H-1,2,4-triazole-5(4H)-thione (6) with various substituted aldehydes. Structures of the newly synthesized compounds were characterized by FT-IR, ¹H NMR and ¹³C NMR spectral analysis. All the synthesized derivatives were screened for their in vivo anti-inflammatory and in vitro anti-oxidant activities using carrageenan induced rat paw edema test and DPPH free radical scavenging assay, respectively. In addition, molecular docking experiment was also performed to check the actual binding affinity of ligand against target protein. Compounds 4a, 4c, 7a, and 7c screened as potent anti-inflammatory drugs significantly lowered the volume of rat paw edema (P < 0.05). In case of anti-oxidant assay, compound 7a with ferrocenyl group as substituent R and 3,4-disubstitued 1,2,4-triazole as side coupled group exhibited IC₅₀ value of 7.2 ± 2.7 μg/mL comparable with that of the reference ascorbic acid (2.61 ± 0.29 μg/mL) and was the most active compound among the series. However, no prominent results were obtained in case of aralkanoic acid hydrazide substituted Schiff base derivatives 4a – 4d. It is believed that the synthesized Schiff base derivatives can be used for the development of potent anti-inflammatory and anti-oxidant drugs with considerable advantages of convenient synthetic strategy possessing high product yield, short reaction time, and convenient handling. The molecular docking results were found in good correlation with experimental IC₅₀ values.