Triterpenoidal saponin and phenolic glycosides from Rhododendron barbatum flowers

A triterpenoidal saponin, hederagenin-3-O-{β-D-arabinopyranosyl (1→4) α-L-rhamnopyranoside} (1); a flavonoid glycoside, flavonone-4’-hydroxy 7-O-{β-D-glucopyranosyl (1→6) β-D-xylopyranoside} 5’-O-β-D-glucopyranoside (2) and a xanthone glycoside, xanthone-1-hydroxy-3-methoxy-7-O-{β-D-xylopyranosyl (1→4) α-L-rhamnopyranosyl(1→4) β-D-xylopyranosyl (1→3) β-D-xylopyranoside} (3) along with five known compounds, quercetin-7-O-β-Dglucopyranoside; β-sitosterol-β-D-glucopyranoside; quercetin; β-sitosterol and oleanolic acid were isolated from the flowers of Rhododendron barbatum. Their structures were elucidated by means of chemical and spectral studies.