ABSTRACT
OBJECTIVE: To study the effects of Tamarindus indica L. aqueous fruit extract on the antinociceptive activities in rodent models. METHODS: The analgesic effect was evaluated using acetic acid-induced writhing, hot plate and formalin tests. RESULTS: The extract (60-600 mg/kg) significantly (p < 0.05) inhibited the writhing test in a dose-dependent manner with the percentage of analgesia recorded between 51.8 and 74.1%. In addition, the extract also significantly (p < 0.05) increased the latency time in the hot plate test in a dose-dependent manner. Further study showed that the extract elicited inhibitory activity in both the early and late phases of the formalin test. Moreover, pretreatment with 5 mg/kg naloxone, a nonselective opioid receptor antagonist, significantly (p < 0.05) modified the antinociceptive effect of the extract in all tests. CONCLUSION: The aqueous extract of T. indica possesses potential antinociceptive activity at both the peripheral and central levels, which are mediated via activation of the opioidergic mechanism.
