Three new α-glucosidase inhibitory benzo-isochromenes were isolated from the chloroform fraction of Datura stramonium. Their structures were established with the help of modern spectroscopic techniques and were assigned the names as 1,6,8-triimethoxy-2-methyl-3,4-dihydrobenzoisochromene-5,10-diol, 3,6-dimethoxy-5-hydroxy-4-methylbenzoisochromene-9,11-dione and demethylflavasperon for compounds 1-3 respectively. The α-glucosidase inhibiting activity of compound 2 showed strong inhibition with an IC50 value of 27.5 µM, while compound 1 exhibited moderate activity with IC50 value of 60.2 µM compared to positive control (acarbose).
Keywords: Anti-diabetic compounds; Datura stramonium; benzo-isochromenes; isolation; α-glucosidase.