Phloroglucinol derivatives with α-glucosidase inhibitory activities from Syzygium fluviatile

Four new phloroglucinol derivatives (1 − 4) were isolated from the leaves of Syzygium fluviatile. Their structures were elucidated by means of extensive spectroscopic data. Among them, compounds 1 and 3 showed significant inhibitory activity against α-glucosidase with IC50 values of 10.60 and 5.07 µM, respectively. The structure-activity relationship was also discussed briefly.