Antipyretic and antinociceptive potential of Ricinus communis L. and Withania somnifera L. hydroalcoholic extracts in Wistar rats: A comparative study.

The present study was designed to evaluate the antipyretic and antinociceptive activities of R. communis leaves and W. somnifera roots hydroalcoholic extracts in Wistar rats. To assess the antipyretic activity, Brewer's yeast suspension was used to induce hyperthermia. Antinociceptive activity was observed using acetic acid-induced abdominal writhing, formalin-induced paw licking reflex and heat-induced pain models. R. communis and W. somnifera extracts were used at 150, 250 and 500mg/kg. Results showed that administration of both plants significantly (p<0.001) lowered rectal temperature (°C) in a dose-dependent manner from 1h to 4h of study. R. communis and W. somnifera extracts showed a dose-dependent reduction in abdominal writhing induced by acetic acid and decreased the paw licking reflex in formalin-induced nociceptive response. In the heat test, R. communis and W. somnifera extracts exhibited significant (p<0.001) analgesic effects evidenced as an increase in latency time. However, R. communis exhibited prominent antipyretic and antinociceptive activities at 250 and 500mg/kg as compared to W. somnifera. Conclusively, R. communis and W. somnifera could be a potential source of antipyretic and analgesic agents which require further studies.