The analgesic and anticonvulsant effects of Piperine in mice

This study was carried out to investigate the analgesic and anticonvulsant effects of piperine and its possible mechanism of action in mice. The analgesic effect was assessed in acetic acid induced writhing and tail flick tests, while the anticonvulsant effect was studied in pentylenetetrazole (PTZ)‐ and picrotoxin (PIC)‐induced seizure models. The administration of piperine (30, 50 and 70 mg/kg; i.p.) exhibited a significant inhibition (P<0.01) of the acetic acid‐induced writhing. In the tail flick assay, piperine (30 and 50 mg/kg; i.p.) and morphine (5 mg/kg; i.p.) caused a significant (P<0.01) increase in the reaction time of mice. Pre‐treatment of animals with naloxone (5 mg/kg; i.p.), reversed the analgesic effect of both piperine and morphine in the tail flick assay, suggesting the involvement of opioid pathway in the observed analgesic effect of piperine. On the other hand, piperine (30, 50 and 70 mg/kg; i.p.), significantly (P<0.01) delayed the onset of PTZ and PIC‐induced seizures in mice. Similarly valproic acid and diazepam, used as standard anticonvulsants, suppressed the PTZ and PIC‐induced seizures in mice, suggesting that piperine may produce its anticonvulsant effect by enhancing GABA‐ergic neurotransmission in the brain. The results of this study show that piperine possesses analgesic and anticonvulsant properties in mice. Additionally, these effects of piperine may be partly mediated via opioid and GABA‐ergic pathways, respectively. Moreover, these finding may substantiate the folkloric uses of black pepper in the management of pain and epilepsy.