A new benzofuran glycoside from the fruit of Clausena lansium

In this work, we isolated a new benzofuran glycoside, 6-β-d-glucosyl-6,7-dihydroxy-5-benzofuranpropanoic acid methyl ester (1), together with six known compounds (2-7) from the fruits of Clausena lansium (Lour.) Skeels. Extensive spectroscopic methods were employed to elucidate their structures. Herein, compounds 2, 3, 5 and 6 were reported from Clausena lansium (Lour.) Skeels for the first time. Moreover, compounds 1, 2, 4 and 6 showed comparable 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity to l-ascorbic acid, and compound 4 also exhibited potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP). All of the compounds showed oxygen radical absorbance capacity (ORAC) values ranging from 0.3 to 3.6 μmol trolex equivalent/μmol. In addition, compounds 3 and 5 also demonstrated good α-amylase inhibitory activity.

Keywords: Clausena lansium (Lour.) Skeels; amylase inhibition; antioxidant activity; benzofuran glycoside; phenolics; wampee.