α-glucosidase inhibitory activity and lipid-lowering mechanisms of Moringa oleifera leaf extract

Objectives and Materials and Methods: Medicinal plants constitute an important source of potential therapeutic agents for diabetes and hyperlipidemia. The purpose of present study was to investigate the effect of leaf extract of Moringa oleifera on inhibition of alpha-glucosidase and pancreatic alpha-amylase related to diabetes mellitus. Moreover, the study was also determined in vitro bile acid binding capacity as well as inhibition of cholesterol micellization, pancreatic lipase, and cholesterol esterase activity. Results: The phytochemical analysis indicated that total phenolic, flavonoid, and condensed tannin contents in the extract were 45.21 +/- 0.96 mg gallic acid equivalents/g extract, 15.39 +/- 0.58 mg catechin equivalents/g extract, and 4.90 +/- 0.20 catechin equivalents/g extract, respectively. In addition, the extract contained a specific inhibitor of intestinal sucrase than intestinal maltase with IC50 value of 0.78 +/- 0.21 mg/ml, whereas it slightly inhibited pancreatic alpha-amylase and pancreatic cholesterol esterase. However, the extract had no inhibitory activity against pancreatic lipase. Furthermore, taurodeoxycholic acid, taurodeoxycholic acid, and glycodeoxycholic acid were bound to the extract (1 mg/ml) with a degree of 26.90 +/- 0.37%, 21.78 +/- 0.68%, and 22.59 +/- 1.02%, respectively. Finally, the extract (10 mg/ml) markedly inhibited the formation of cholesterol micelle about 40.22 +/- 2.64%. Conclusion: Our results indicated that the leaf extract of Moringa oleifera may be used for the control of blood glucose and lipid concentration and prevention of hyperglycemia and hyperlipidemia.