Investigation of α-glucosidase inhibitory activity of wheat bran and germ

Postprandial hyperglycaemia is a primary risk factor in the development of Type 2 diabetes. α-Glucosidase inhibitors that reduce postprandial hyperglycaemia have a key role in the treatment of Type 2 pre-diabetic states and also have the potential to reduce the progression to complications of diabetes. Epidemiological studies showed that risk for Type 2 diabetes mellitus was decreased with consumption of whole grains. The bran and germ of whole wheat are major components of whole grain consumption and are widely accepted as important ingredients in many low glycaemic index (GI) foods. In this study, the α-glucosidase inhibitory activity of wheat bran and germ was investigated. The active compounds were screened using an in vitro enzyme-inhibitory assay guided fractionation. Potent α-glucosidase inhibitory compounds from wheat germ were identified as phosphatidic acids, 1,2-dilinoleoylglycero-3-phosphate and 1-palmitoyl-2-linoleoyl-glycero-3-phosphate. The low GI property of whole grain wheat could be attributed to these α-glucosidase inhibitory phosphatidic acids, which have the potential to prevent or treat Type 2 diabetes.