Abstract

The present study aims to investigate the anti-pyretic and anti-inflammatory effects of the methanolic extract of the rind of Citrullus lanatus on male albino Wistar rats. Two set of rat groups designated groups 1 to 5 and A to E were used respectively for the anti-pyretic and anti-inflammatory studies. For the antipyretic study, fever was induced by subcutaneous injection of 20 ml/kg of a 20% suspension of brewer’s yeast in normal saline. Group 1 served as negative control and received 2 ml/kg bw of extract vehicle, groups 2, 3 and 4 received 100, 200 and 500 mg/kg bw of the methanolic extract of the rind Citrullus lanatus, respectively and group 5 served as positive control and received 100 mg/kg of aspirin. Rectal temperatures were determined in all rats at hourly intervals for 4 consecutive times. For the anti-inflammatory study, acute inflammation was induced by sub-plantar injection of 0.1 ml of egg albumin into the left hind paw. Groups A to E rats were treated similar as groups 1 to 5 rats. Paw circumference was subsequently determined with the aid of a Vernier caliper at 30, 60, 90 and 120 min post induction of inflammation. Significant reduction in rectal temperatures were observed for both groups 3 and 4 rats (p<0.05): reducing from an initial value of 38.16±0.67°C 18 h post induction of pyrexia to 36.33±0.21°C 4 h post treatment amongst group 3 rats. A significant reduction in hind paw circumference was also observed for both groups C and D rats (p<0.05). For instance, amongst group D rats, there was a significant reduction in hind paw circumference from 3.30±0.00 mm at 30 min to 3.04±0.06 mm at 120 min post induction of inflammation. In conclusion, the present study reports the potential anti-pyretic and anti-inflammatory effects of the methanolic extract of the rind of C. lanatus.

Key words: Anti-inflammatory, antipyretic, Citrullus lanatus, egg albumin, brewer’s yeast.