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.

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