Antihyperglycemic and hypolipidemic effects of α, β-amyrin, a triterpenoid mixture from Protium heptaphyllum in mice

BACKGROUND: Pentacyclic triterpenes in general exert beneficial effects in metabolic disorders. This study investigated the effects of α, β-amyrin, a pentacyclic triterpene mixture from the resin of Protium heptaphyllum on blood sugar level and lipid profile in normal and streptozotocin (STZ)-induced diabetic mice, and in mice fed on a high-fat diet (HFD). FINDINGS: Mice treated with α, β-amyrin (10, 30 and 100 mg/kg, p.o.) or glibenclamide (10 mg/kg, p.o.) had significantly reduced STZ-induced increases in blood glucose (BG), total cholesterol (TC) and serum triglycerides (TGs). Unlike glibenclamide that showed significant reductions in BG, TC and TGs in normoglycemic mice, α, β-amyrin did not lower normal blood sugar levels but at 100 mg/kg, manifested a hypolipidemic effect. Also, α, β-amyrin effectively reduced the elevated plasma glucose levels during the oral glucose tolerance test. Moreover, the plasma insulin level and histopathological analysis of pancreas revealed the beneficial effect of α, β-amyrin in the preservation of beta cell integrity. In mice treated orally with α, β-amyrin (10, 30 and 100 mg/kg) or fenofibrate (200 mg/kg), the HFD-associated rise in serum TC and TGs were significantly less. The hypocholesterolemic effect of α, β-amyrin appeared more prominent at 100 mg/kg with significant decreases in VLDL and LDL cholesterol and an elevation of HDL cholesterol. Besides, the atherogenic index was significantly reduced by α, β-amyrin. CONCLUSIONS: These findings reflect the potential antihyperglycemic and hypolipidemic effects of α, β-amyrin mixture and suggest that it could be a lead compound for drug development effective in diabetes and atherosclerosis.