Synthesis and Evaluation of Analgesic and Antioxidant Activities of Substituted Benzimidazole Derivatives

Synthesis and Evaluation of Analgesic and Antioxidant Activities

Abstract

The present study describes the synthesis and pharmacological evaluation of a number of substituted benzimidazole derivatives designated by 3A-1, 3A-2, 3A-3, 3B-1 and 3B-2 through condensation of different o-aryldiamine compounds with the corresponding aldehyde employing ammonium salt as a catalyst. All the compounds were characterized by IR and ¹H NMR spectroscopic analysis. The synthesized benzimidazole derivatives were investigated for analgesic and antioxidant activities using acetic acid-induced writhing inhibition in Swiss albino mice and DPPH free radical scavenging assay, respectively. Compounds 3A-3, 3B-1 and 3B-2 at a dose of 50 mg/kg body weight reduced the number of writhings by 88.24%, 84.03% and 85.71%, respectively (p<0.001) in comparison with standard diclofenac (90.76% inhibition). The derivatives 3A-1, 3A-2, 3A-3 and 3B-2 showed prominent antioxidant activity with IC₅₀ values of 0.038, 0.959, 8.834 and 7.519 μg/ml, respectively in comparison with the standard butylated hydroxytoluene (BHT) (14.44 μg/ml). Among the synthesized compounds, 3A-3 and 3B- 2 emerged as the most promising analgesic and antioxidant agents and expressed their potential as lead compounds in future research.

Dhaka Univ. J. Pharm. Sci. 19(1): 37-46, 2020 (June)