Ethanolic Root Extract of Jatropha curcas L. Relieves Muscle Pain in Rats

Abstract

The roots of Jatropha curcas are used traditionally to treat pain. The present study evaluated the analgesic property of ethanolic extract of Jatropha curcas (JAT) in acute and chronic muscle pain models. Acute muscle hyperalgesia was induced by injecting 3% carrageenan into the gastrocnemius muscles of rats. Twelve hours after the injection, baseline muscle hyperalgesia was measured and the rats were then treated orally with 30, 100 and 300 mg/kg/day JAT; intraperitoneally with 1, 3 and 10 mg/kg/day morphine and normal saline. A change in pain threshold was assessed with the grip strength analgesimeter. The effect of JAT on chronic muscle hyperalgesia was evaluated by injecting 3% carrageenan into the gastrocnemius muscles of the separate groups of rats. Two weeks later, baseline pain thresholds were measured and rats were treated with 30, 100 and 300 mg/kg/day JAT; 1, 3 and 10 mg/kg/day morphine and normal saline. Pain threshold was assessed again by measuring the latency to paw withdrawal in the ipsilateral and contralateral paws. JAT and morphine increased the grip strength in the acute muscle hyperalgesia test. Chronic muscle hyperalgesia was also significantly reduced by JAT and morphine. JAT relieves muscle pain in rats.