In vitro and in vivo antidiabetic potential of extracts and a furostanol saponin from Balanites aegyptiaca

Abstract

Context:Balanites aegyptiacaDel. (Zygophyllaceae) fruits are well-known antidiabetic drug in Egyptian folk medicine. Nevertheless, its mechanism of action is still unclear. Objectives:Searching for the possible mechanisms of action of the plant and identification of its bio- active compounds. Materials and methods:A bio-guided protocol based on the evaluation ofa-glucosidase (AG) and aldose reductase (AR) inhibitory activities was adopted to isolate the biologically active compounds from the methanol extract (MeEx). Anin vivoantidiabetic study was conducted for the active extract, fraction and compound using streptozotocin-induced diabetic male albino Wistar rats at two dose levels (100 and 200 mg/kg.b/wt) for 2 weeks. Results:Three compounds were isolated and identified: a sterol, (1) stigmasterol-3-O-b- D-glucopyranoside; a pregnane glucoside, (2) pregn-5-ene-3b,16b,20(R)-trio1-3-O-b- D-glucopyranoside; a furostanol saponin, (3)26-(O-b- D-glucopyranosyl)-22-O-methylfurost-5-ene-3b,26-diol-3-O-b-D-glucopyranosyl-(1!4)-[a-L-rham- nopyranosyl-(1!2)]-b- D-glucopyranoside. Only compound3possessed significant AG and AR inhibitory activities (IC 50 ¼3.12 ± 0.17 and 1.04 ± 0.02lg/mL, respectively), while compounds1and2were inactive. Thein vivoantidiabetic study revealed that MeEx and furostanol saponin3possessed significant activities at a dose of 200mg/kg through reducing the fasting plasma glucose level by 46.14% and 51.39%, respect- ively, as well as reducing the total cholesterol by 24.44% and 31.90%, respectively. Compound3also caused increment in insulin and C-peptide levels by 63.56% and 65%, respectively. Discussion and conclusions:We presented a scientific base for usingBalanites aegyptiaca, and shed the light on one of its saponins, as an antidiabetic agent in fasting and postprandial hyperglycaemia along with the improvement of diabetic complications.