α-glucosidase and α-amylase inhibitory activities of medicinal plants in Thai antidiabetic recipes and bioactive compounds from Vitex glabrata R. Br. stem bark

In this study, the 37 medicinal plants selected from two Thai folk antidiabetic recipes (Mor-Phon recipe and the recipe of Wang-Nam-Yen hospital, Thailand) were investigated for their potential anti-diabetic mechanisms via α-glucosidase and α-amylase inhibitory activities. The highest α-glucosidase inhibitory activity was observed in the ethanolic extracts of Salacia chinensis, Vitex glabrata, Senna siamea, Terminalia catappa, and Phyllanthus amarus and the highest α-amylase inhibitory activity was observed in the ethanolic extracts of T. catappa, V. glabrata, P. amarus, S. chinensis, and S. siamea. The stem bark of V. glabrata was identified as the most bioactive plant and was thus isolated by bioassay-guided fractionation to obtain six known compounds, lupeol (1), β-amyrin (2), α-amyrin (3), betulin (4), betulinic acid (5), and scopoletin (6). The α-glucosidase and α-amylase inhibitory activities of those isolated compounds were tested. The highest α-glucosidase and α-amylase inhibitory activities were observed by lupeol (1) (IC50 7.4 µM) and β-amyrin (2) (IC50 32.33 µM), respectively. However, compounds 3 – 5 also showed good inhibition in both digestive enzymes.
Source: Journal of Herbal Medicine - Category: Complementary Medicine Source Type: research