In vitro antihyperlipidemic activity of triterpenes from stem Bark of Protorhus longifolia (Benrh) Engl.

Obesity is a common disorder of carbohydrate and fat metabolism. In an effort to discover new more effective drugs against obesity and its co-morbidities, we investigated the in vitro antihyperlipidemic activity of two triterpenes (3β-hydroxylanosta-9,24-dien-21-oic acid and methyl-3β-hydroxylanosta-9,24-dienoate isolated from stem bark of Protorhus longifolia and characterized through NMR, LC-MS, IR. The inhibitory activity of the triterpenes was evaluated on selected lipid (pancreatic lipase and cholesterol esterase) and carbohydrate (disaccharidases, α- glucosidase) digestive enzymes. The inhibitory activity of the compounds on hormone-sensitive lipase and the ability to bind bile acids were also evaluated. Furthermore, the effect of the compounds on cellular (muscle cells, C2C12 and fat cells, 3T3-L1) glucose uptake was investigated. The triterpenes effectively inhibited the activities of pancreatic lipase, cholesterol esterase, and hormone-sensitive lipase with IC50 values ranging from 26.6 to 430 µg/ml, and showed to varying degree inhibition of maltase and other disaccharidases. The compounds showed moderate bile acid binding ability and at 50 µg/ml, both compounds also mimicked insulin character by effectively stimulating glucose uptake in both the C2C12 and 3T3-L1 cells. It is apparent that the compounds possess hypolipidemic properties.