Effect of ethanolic extracts of Justicia neesii Ramam. against experimental models of pain and pyrexia

OBJECTIVE: The main objective of this study is to evaluate the analgesic and anti-pyretic activities of ethanolic extracts of Justicia neesii Ramam. by different experimental models. MATERIALS AND METHODS: The analgesic activity of plant extract was evaluated against thermal and chemical stimulus induced by Eddy's hot plate and acetic acid respectively in mice. Brewer's yeast induced pyrexia was used to evaluate the antipyretic activity in rats and TAB vaccine induced pyrexia was used to evaluate the antipyretic activity in rabbits. RESULTS: In the hot plate model 400 mg/kg p.o. dose of J. neesii has shown its maximal effect at 3 h. The results are significant (P < 0.05) and comparable to the values of standard drug pentazocine (30 mg/kg i.p.). In acetic acid induced writhing model 400 mg/kg p.o. of plant extracts have shown highly significant activity (P < 0.001) and better than standard drug indomethacin (10 mg/kg p.o.). The 400 mg/kg p.o. dose of plant extract has given significant results against both yeast induced pyrexia and TAB vaccine induced pyrexia (P< 0.01 and 0.05 respectively). These values are comparable to that of paracetamol 100 mg/kg p.o. standard dose. CONCLUSION: This study shows that the ethanol extract of J. neesii has significant analgesic and antipyretic activity.