Here we evaluated the antinociceptive effects of the extract from the bulbils of Dioscorea bulbifera L. var sativa (Dioscoreaceae) in persistent inflammatory and neuropathic models of pain in mice, in order to assess some of the mechanisms involved in its actions. This plant is used in Cameroonian traditional medicine in the treatment of many pathologies including pain. The analgesic effects were evaluated on three models of acute pain induced by LPS, PGE2 and capsaicin, one model of chronic inflammatory pain induced by CFA and two models of neuropathic pain induced after avulsion of the brachial nerve and sciatic nerve ligature. Oral administration of the methanol extract inhibited significantly and in a dose-dependent manner the different models of pain used. The methanol extract of D. bulbifera significantly inhibited acute pain induced by LPS and prostaglandin E2, the inflammatory pain induced by CFA and the neuropathic pains induced by avulsion of the brachial nerve and sciatic nerve ligature; in addition, on the other hand this extract did not have an effect on the capsaicin induced pain. The analgesic activity of the methanol extract of D. bulbifera was inhibited by L-NAME and glibenclamide on the prostaglandin E2 induced pain. These results suggest that, the analgesic effect of the extract of D. bulbifera could result from an activation of the NO/GMPc/ATP dependent potassium channel. These results show that the bulbils of D. bulbifera possess analgesic properties. In conclusion, Dioscorea bulbifera L. var sativa have therapeutic virtues, which justify its use in traditional medicine. The results of this study show that this plant is equipped with pharmacological analgesics properties and probably anti-inflammatory.
© 2011 Published by Elsevier Inc.