Phenylethanoid Glycosides from Digitalis viridiflora

From the MeOH extract of the leaves of Digitalis viridiflora five phenylethanoid glycosides (1-5) including a new one were isolated. The structure of the new compound was established as 3,4-dihydroxy-β-phenylethoxy-O-β-quinovopyranosyl-(1 ® 6)-4-O-caffeoyl-β-glucopyranoside (viridifloroside, 1) based on extensive 1D- and 2D-NMR spectroscopy as well as MS. Compound 1 is the first example of a phenylethnoid glycoside bearing a quinovopyranose in its structure. The chemotaxonomic importance of the isolates was also discussed.