A phenylethanoid glycoside from Plantago asiatica.

A new phenylethanoid glycoside, plantasioside, was isolated from the aerial parts of Plantago asiatica. The structure of plantasioside was deduced from chemical and spectral evidence to be 1',2'-[beta(3,4-dihydroxyphenyl)-alpha,beta-dioxoethanol]-6'-O- caffeoyl- O-beta-D-glucopyranoside. In addition, the structure of orobanchoside from P. depressa and P. camtschatica was revised to be 1',2'-[beta(3,4-dihydroxyphenyl)- alpha,beta-dioxoethanol]-4'-O-caffeoyl-O-alpha-L-rham- nopyranosyl-(1-->3)-O- beta-D-glucopyranoside from beta-hydroxy-[beta(3,4-dihydroxyphenyl)-ethyl]-4'-O-caffeoyl-O-alp ha-L- rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranoside.