α-glucosidase inhibitor activity of Terminalia species

Abstract

Terminalia arjuna, Terminalia ballerica, Terminalia chebula, Terminalia catappa, Terminalia kaerbachii and Terminalia microcarpa leaves were tested for their α-glucosidase inhibitory activity in vitro. The α-glucosidase activity was determined by measuring the p-nitrophenol release from pNPG at 400 nm. Terminalia kaerbachii has the highest α-glucosidase inhibitor activity with IC50 value of 0.27±0.17 μg mL-1 and is a promising antidiabetic herbal medicine candidate. However, most of the Terminalia species are also potential as antidiabetic medicine candidates as the IC50 values are approximately 5 μg mL-1, which is near the IC50 value of 1-deoxynojirimycm, the reference compound, except for Terminalia microcarpa, which has IC50 value of 25.15±0.04 μg mL-1 (above 21 μg mL-1). From the phytochemical screening, Terminalia kaerbacchi contains alkaloids, flavonoids and cathechic tannins, but does not contain saponin, quinon, steroid/terpenoids and gallic tannins. It is estimated that there is a correlation between α-glucosidase inhibitory activity and its phytochemical content. © 2009 Asian Network for Scientific Information.