Triptexanthosides A - E: Xanthone glycosides from aerial parts of Tripterospermum japonicum

Abstract

From the aerial parts of Tripterospermum japonicum, five new xanthone glycosides, named triptexanthosides A - E, were isolated along with a known xanthone C-glucoside, mangiferin. Their structures were elucidated as 1,2,6,8-tetrahydroxyxanthone (norswetianin) 1-O-β-D-glucopyranoside and 1- O-β-gentiobioside, and 1,2,8-trihydroxy-5,6-dimethoxyxanthone 2-O-β-D- glucopyranoside, 2-O-β-primeveroside and 1-O-gentiobioside, respectively, from spectroscopic evidence and acid hydrolysis.