Evaluation of Antinociceptive, Antidiarrheal and Antimicrobial Activities of Leaf Extracts of Clerodendrum indicum

Introduction: The methanolic extracts and its different partitioning fractions of leaves of Clerodendrum indicum were evaluated for their anti-nociceptive, anti-diarrheal and in vitro antimicrobial activities. Methods: The anti-nociceptive activity was evaluated using the acetic acid-induced writhing test in mice; the anti-diarrheal activity was investigated by the effect of extracts on castor oil-induced diarrhea while the in vitro antimicrobial activities were examined by the disc diffusion method. Results: In the acetic acid-induced writhing test, the methanolic extract at a dose of 200 and 400 mg/kg showed a significant (p<0.001) and dose-dependent reduction in the number of writhes with 62.57% and 70.76% of inhibition, respectively, while the CCL4 fraction at the same dose showed potent anti-nociceptive activity (p<0.001) with 73.09% of inhibition of writhing which was even higher than that of standard diclofenac sodium (55.56% inhibition). The methanolic extract, CCL4 and chloroform fraction showed moderate activity against the tested microorganisms in terms of both zones of inhibition (ranged from 9-13 mm, 10-13 mm and 10-13 mm, respectively, at a concentration of 400 µg/disc) and spectrum of activity. In castor oil-induced diarrhea testing, the methanolic extract and chloroform fraction at a dose of 400 mg/kg produced 21.74% and 26.96% inhibition of defecation, respectively, which were found to be comparable to that of standard drug loperamide (37.39% inhibition at 50 mg/kg ) with regard to the severity of diarrhea. Conclusion: The results of the investigation demonstrated that the methanolic extract and its different fractions of leaves of Clerodendrum indicum possess significant anti-nociceptive, antimicrobial and antidiarrheal activities.