ABSTRACT

Type 2 diabetes mellitus (T2DM) is a chronic progressive disease that has continued to be a global heath and economic burden. Acarbose is an antidiabetic drug, which acts by inhibiting alpha amylase and alpha glucosidase; while gallic acid is a simple phenolic acid that is widespread in plant foods and beverages such as tea and wine.This study therefore, sought to investigate the influence of gallic acid on α-amylase and α-glucosidase inhibitory and antioxidant properties of acarbose (in vitro). Aqueous solution of acarbose and gallic acid were prepared to a final concentration of 25µM each. Thereafter, mixtures of the samples (50% acarbose + 50% gallic acid; 75% acarbose + 25% gallic acid; 25% acarbose + 75% gallic acid) were prepared. The results showed that the combination of 50% acarbose and 50% gallic acid showed the highest α-glucosidase inhibitory effect, while 75% acarbose + 25% gallic acid showed highest α- amylase inhibitory effect. Furthermore, all the samples caused the inhibition of Fe2+ -induced lipid peroxidation (in vitro) in rat pancreatic tissue homogenate, with the combination of 50% acarbose and 50% gallic acid causing the highest reduction in the malondialdehyde content. In addition, all the samples showed antioxidant properties (ferric reducing property, 2, 2'-azino-bis (-3-ethylbenzthiazoline-6-sulphonate (ABTS*) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging abilities, and Fe2+ chelating ability). Therefore, the combinations of gallic acid with acarbose could be employed in the management of T2DM with the comparative advantage of possible reduction of the side effects of acarbose; nevertheless the combination of 50% acarbose and 50% gallic acid seems the best combinatory therapy for the management of type 2 diabetes mellitus.