Some pharmacological studies on Morinda lucida

Objective: The methanol extract (MLE) and fractions (MLFX₂ and MLFX₅) isolated from Morinda lucida were studied for some pharmacological properties in animal models. Methods: Carrageenan-induced rat paw oedema model was used to test anti-inflammatory activity; the acetic acid-induced writhings and tail immersion test were used to evaluate analgesic effect; while antipyretic activity was evaluated by inducing pyrexia with lipopolysaccharide, and measuring the rectal temperature. The effect of MLE on phenobarbitone sleeping time was also tested. Results: MLE (6.25-50 mg/kg), and MLFX₂ and MLFX₅ (5 and 10 mg/kg) produced inhibition of the carrageenan-induced rat paw oedema. MLE (50-200 mg/kg) significantly reduced the number of writhings induced by acetic acid and elevated pain threshold in hot water test. MLFX₅ significantly (P<0.05) reduced lipopolysaccharide-induced hyperpyrexia in rats while MLFX₂ exhibited no such effects. MLE was also found to potentiate phenobarbitone induced sleeping time. Conclusion: MLE, MLFX₂ and MLFX₅ exhibited anti-inflammatory activity; MLE also showed analgesic, antipyretic effects and potentiated phenobarbitone sleeping time. However, MLFX₂ showed analgesic activity in the acetic acid test while MLFX₅ exihibited antipyretic effect.