Coumarins and carbazole alkaloid from Clausena excavata roots and investigation of their α-glucosidase inhibitory activity

Abstract

Clausena excavata Burm.f. has long been associated with medicinal benefits in folk medicine. This study isolated three known compounds which are two coumarins, umbelliferone (1), clausenidin (2) and one carbazole alkaloid, (2-hydroxy-3-formyl-7-methoxycarbazole (3) from the root of the plant. The compounds were characterized using their 1H-NMR, 13C-NMR, COSY, HSQC and HMBC spectra and confirmed by literature data. The α-glucosidase inhibitory activity of the extract, fractions, compounds 2 and 3 were evaluated. The methanol extract exhibited higher inhibition against maltase α-glucosidase with IC50 value 0.020 mg/mL than the n-hexane fraction which IC50 value was 0.041 mg/mL.