Inhibitory effects of aqueous extract of two varieties of ginger on some key enzymes linked to type-2 diabetes in vitro.

Management of the blood glucose level is a critical strategy in the control of diabetes complications. Inhibitors of saccharide hydrolysing enzymes have been useful as oral hypoglycemic drugs for the control of hyperglycemia especially in patients with type-2 diabetes mellitus. This study compares the phenolic contents and antioxidant properties of two varieties of ginger, namely, Red (Zingiber officinale var. Rubra) and white (Zingiber officinale Roscoe), and their inhibitory effects on the activities of α-amylase and α-glucosidase (key enzymes linked to type-2 diabetes) using an in vitro model. The results show that the aqueous extracts of red ginger had significantly (P < 0.05) higher phenolic contents as well as higher antioxidant activities than the aqueous extracts of white ginger. However, contrary to the phenolic contents and antioxidant properties, white ginger had a significantly (P < 0.05) stronger inhibitory effect on α-amylase and α-glucosidase activities than red ginger. Furthermore, both extracts exhibited mild a-amylase and stronger α-glucosidase inhibitory activities, suggesting their potential use in dietary intervention in the management or control of postprandial hyperglycemia associated with type-2 diabetes. White ginger exhibited stronger enzyme inhibitory effects than red ginger. [ABSTRACT FROM AUTHOR]