Interaction of Some Commercial Teas with Some Carbohydrate Metabolizing Enzymes Linked with Type-2 Diabetes: A Dietary Intervention in the Prevention of Type-2 Diabetes

Abstract

This study is aimed at assessing the inhibitory effect of teas on key enzymes ( α -amylase and α -glucosidase) linked with type-2 diabetes and their antioxidant properties. Four samples of three brands were used; infusions of green tea (GT), 2 brands of black tea (BT), and a formulated herbal preparation for diabetes (ADT) (white tea, Radix Puerariae , Radix ophiopogonis , hawthorn berry, Chinese yam, and fragrant Solomon seal rhizome) were prepared and subsequently analyzed for their total phenol, ascorbic acid contents, antioxidant properties (2,2-Azizobis (3-Ethylbenzo-Thiazoline~6-sulfonate) “ABTS” scavenging ability and ferric reducing antioxidant property), and inhibition of pancreatic- α -amylase and intestinal- α -glucosidase in vitro . The study revealed that GT had the highest total phenol content, ascorbic acid content, ABTS* scavenging ability, and ferric reducing ability. Furthermore, all the teas inhibited Fe 2+ and sodium nitroprusside induced lipid peroxidation in pancreas, with GT having the highest inhibitory effect. Conversely, there was no significant difference ( P > 0.05 ) in the inhibitory effects of the teas on α -amylase and α -glucosidase. The antidiabetic property of the teas could be attributed to their inhibitory effect on carbohydrate hydrolyzing enzymes implicated in diabetes and their antioxidant activities.