Flavonoids from Salvia chloroleuca with α-Amylsae and α-Glucosidase Inhibitory Effect

It is believed that the inhibition of carbohydrate hydrolyzing enzymes including alpha-amylase and alpha-glucosidase is one of the therapeutic approaches to decrease the postprandial glucose level after a meal, especially in the people with type 2 diabetes. Medicinal plants and their extracts are one of the main sources to find new inhibitors to the enzymes. In our study four flavonoids, namely luteolin 7-O-glucoside (1), luteolin 7-O-glucuronide(2), diosmetin 7-O-glucuronide (3) and salvigenin (4) were isolated from aerial parts of Salvia chloroleuca. The inhibitory activity of these compounds against alpha-amylase and alpha-glucosidase were evaluated. Compounds 1, 2 and 3 showed potent alpha-glucosidase inhibitory effect with IC50 values of 18.3, 14.7, and 17.1 mu M, respectively. Also these compounds exhibited moderate alpha-amylase activity with IC50 values 81.7, 61.5, and 76.3 mu M, respectively.