Acylated flavone C-glycosides from Trollius ledebouri.

Six new acylated flavone C-glycosides, 2''-O-(2'''-methylbutyryl)isoswertisin (1), 3''-O-(2'"-methylbutyryl)isoswertisin (2), 2''-O-(2'"-methylbutyryl)vitexin (3), 2''-O-(2'"-methylbutyryl)orientin (4), 2''-O-(3'",4'"-dimethoxybenzoyl)vitexin (5), and 2''-O-(3'",4'"-dimethoxybenzoyl)orientin (6), and the known flavone C-glycoside, isoswertisin, were isolated from the flowers of Trollius ledebouri. The structures of 1-6 were elucidated by spectroscopic methods.