New Triterpene Sulfates from Vietnamese Red Alga Tricleocarpa Fragilis and Their α-glucosidase Inhibitory Activity

Abstract

Three new compounds (methyl-3b,25-dihydroxycycloart-23-en-29- oate 3-sulfate (1), methyl-3b-hydroxy-25-methoxycycloart-23-en- 29-oate 3-sulfate (2) and 3b-hydroxy-25-methoxycycloart-23-ene 3-sulfate (3)) and a known one (3b-hydroxycycloart-24-en-23-one 3-sulfate (4)) were isolated from Vietnamese red alga Tricleocarpa fragilis. All isolated compounds 1-4 showed potent inhibitory activity against yeast a-glucosidase with IC50 values of 16.62 ± 2.80, 36.34 ± 4.04, 30.19 ± 5.01 and 6.52 ± 0.17 mM, respectively. The docking data showed that the substitutions at C-3 and the differences in the side chain of cycloartane-skeleton could influence the interaction of molecule with enzyme, which was consistent with the experimental findings.