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

It is believed that the inhibition of carbohydrate hydrolyzing enzymes including α-amylase and α-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 α-amylase and α-glucosidase were evaluated. Compounds 1, 2 and 3 showed potent α-glucosidase inhibitory effect with IC50 values of 18.3, 14.7, and 17.1 µM, respectively. Also these compounds exhibited moderate α-amylase activity with IC50 values 81.7, 61.5, and 76.3 µM, respectively.