Rauvolfia vomitoria is a medicinal plant that has been implicated for various medicinal actions including anti-diabetic. But among the various literature on its anti-diabetic action, none has provided information on the phytoconstituents responsible for its anti-diabetic action, the mechanisms of action as well as its effect on plasma insulin and glucagon (the primary regulators on blood glucose). Thus the aim of this study was to investigate the active phytoconstituents of Rauvolfia vomitoria leaf extract as well as its possible mechanisms of action with respect to diabetic treatment. GC-MS analysis of the hydromethanolic extract of Rauvolfia vomitoria revealed phytol as its major phytoconstituent with 38.73% percentage abundance. Diabetes was induced via intraperitoneal injection of 55mg/kg dose of streptozotocin and treated with whole leaf extract, phytol and glyburide for 28 days. After treatment, phytol caused significant (P<0.05) decrease in blood glucose level by approximately 95.73%, versus 99.5% for the hydromethanolic extract of Rauvolfia vomitoria leaf and 101.9% for the standard anti-diabetic drug, glyburide. These results therefore, showed that phytol is the major phytoconstituent of Rauvolfia vomitoria leaves responsible for its anti-diabetic action and can be further exploited for anti-diabetic medications.

Keywords: Rauvolfia vomitoria, anti-diabetic, streptozotocin, glyburide, GC-MS, phytoconstituents, phytol