Pennisetum purpureum (Elephant or Napier grass) is being used in East Africa and some other parts of the world as animal feed and also in pulp industry. In some parts of South eastern Nigeria where it is popularly known as â€˜â€™Acharaâ€˜â€™ it is a delicacy in some traditional dishes. In recent studies, its nutritional and non-nutritional components reveal that it contains flavoids, saponin, sterols, glycosides, tannins and high content of vitamins and Irons. Flavoids, saponin and glycosides are known for their ability to inhibit pain. The study is aimed at evaluating the analgesic activity of the ethanol extract of P. purpureum in experimentally induced acetic acid writhing in mice. P. purpureum shoot extract were prepared with the help of Soxhlet apparatus. The analgesic activities were observed using acetic acid induced writhing and compared with Aspirin and Acetaminophen used as reference drugs. The result shows that oral administration of the extract, at (P < 0.05) was significant in reducing the number of writhing compared to the negative control (distilled water) and standard drug (Aspirin). Acetaminophen shows no significant inhibition when compared with the extract. 200 mg/kg of the extract compared to 400 mg/kg, shows that 200 mg/kg had better inhibitory effect (43.66%) than 400 mg/kg; this indicates that additional increase in the dose of the extract will not increase the analgesic activity. Conclusively, the plant extract P. purpureum possesses analgesic effect and further analysis should be conducted for it to be used as an analgesic.
Keywords: Pennisetum purpureum, Aspirin, Acetaminophen, pain inhibition