STUDIES ON THE MECHANISM OF THE ANTIDIABETIC ACTIVITIES OF ACHA (DIGITARIA EXILIS) AS AFFECTED BY PROCESSING METHODS

Abstract

In view of the complexity and complications of type-2 diabetes, coupled with the inefficacy and attendant side effects of currently available anti-diabetic drugs (e.g. acarbose) research assertion has continued to increase on the use of alternate ways such as use of functional foods that could be safer, cheaper and more effective for the prevention and management of type-2 diabetes. Acha grains (Digitaria exilis) have been used in traditional medicine for the management of type-2 diabetes for years. This study investigated the effects of processing on Acha grains flours and starch as dietary intervention in diabetics. The flours were processed as cooked, roasted and fermented, screened for their phenolic content, antioxidant properties and their abilities to inhibit two key enzymes linked to the management of type-2 diabetes (α-amylase and α-glucosidase) in vitro. The microscopic sizes of the starches of the processed grains flours were also assessed. Thereafter, the processed Acha flours were formulated into biscuits and their antioxidant properties and effect on blood glucose concentration; α-amylase and α-glucosidase activities were evaluated in apparently normal and diabetic patients. The results revealed that fermented Acha grain had the highest total phenol (13.46mg/g) and flavonoid (9.26mg/g) contents, Fe2+ chelating and α-glucosidase inhibitory abilities, while the roasted grains had the strongest DPPH* scavenging and α-amylase inhibitory abilities. The micrograph of the starch of the processed grains flours revealed that the cooked grain starch had the smallest granules size (2- 9μm), while the fermented (13 - 69μm) had the biggest size. The formulated Acha biscuits lowered the blood glucose concentration, enhanced antioxidant status (as revealed by increased catalase, superoxide dismutase (SOD) and Glutathione-S-transferase activities) and inhibited α-amylase and α-glucosidase activities of apparently healthy and diabetic subjects. The glycemic indices of the Acha-based biscuits were also low in the diabetic (32.08 - 43.92) and healthy subjects (27.54 - 38.45). The formulated Acha biscuits also showed hypocholesterolemic properties by altering the levels of total cholesterol, triglyceride, high density lipoprotein cholesterol and low density lipoprotein cholesterol when compared to diabetic patients that did not consume the biscuits. The Acha based biscuits could be used in the management and prevention of type-2 diabetes. However, roasting is the best method for processing the Acha grains for biscuit production.