A survey of the flavonoid glycosides of selected taxa in the genus Veronica yielded two new acylated 5,6,7,3',4'-pentahydroxyflavone (6-hydroxyluteolin) glycosides and two rare allose-containing acylated 5,7,8,4'-tetrahydroxyflavone (isoscutellarein) glycosides. The new compounds were isolated from V. liwanensis and V. longifolia and identified using NMR spectroscopy as 6-hydroxyluteolin 4'-methyl ether 7-O-alpha-L-rhamnopyranosyl(1'''->2'')[6''-O-acetyl-b-D-glucopyranoside] and 6-hydroxyluteolin 7-O-(6''-O-(E)-caffeoyl)-beta-D-glucopyranoside, respectively. Isoscutellarein 7-O-(6'''-O-acetyl)-beta-D-allopyranosyl(1'''->2'')-beta-D-glucopyranoside was obtained from both V. intercedens and V. orientalis and its 4'-methyl ether from V. orientalis only. Complete 1H and some revised 13C NMR spectral assignments are presented for the known isoscutellarein glycosides. Two iridoid glucosides new to the genus Veronica (melittoside and globularifolin) were also isolated from V. intercedens.
|Publication status||Published - 2003|