Structural elucidation and α‑glucosidase inhibitory activity of a new xanthone glycoside from Lomatogonium rotatum (L.) Fries es Nym.

A new xanthone glycoside, 1,8-dihydroxyl-2,5-dimethoxy-xanthone-6-O-β-D-glucoside (1), along with two known xanthone glycosides and two flavonoid glycosides were isolated from the aerial parts of Lomatogonium rotatum (L.) Fries es Nym. The structure of 1 was elucidated by analysis of its spectroscopic data, including UV, IR, HR-ESI-MS and extensive 1 D and 2 D NMR techniques. In vitro test, compound 1 behaved similarity to swertianolin against α‑glucosidase and more potent inhibitory effects than the positive control, acarbose.