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

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.