HPLC Study of the Flavonoid Composition of Cephalaria gigantea Flowers

Quercimeritrin (3,5,7,3′,4′-pentahydroxyflavone 7-O-β-D-glucopyranoside) and gigantoside B, which is a new natural compound having the structure 3,5,7,3′,4′-pentahydroxyflavone 7-O-[(6″-O-β-D-xylopyranosyl)-β-D-glucopyranoside, were isolated for the first time from flowers of Cephalaria gigantea (Lebed.) Bobr. cultivated in Samara Region. Ahigh-performance liquid chromatography method for quantitative determination of flavonoids (gigantoside B, quercimeritrin, and quercetin) in the H₂O(EtOH extract from C. gigantea flowers was developed. The contents of gigantoside B (the dominant flavonoid), quercimeritrin, and quercetin found in flowers of C. gigantea were 1.49 ± 0.03%, 0.92 ± 0.02%, and 0.57 ± 0.03%, respectively.