Notiz über Ellagitannine und Flavonol‐glycoside aus Rosenblüten

Note on Ellagitannins and Flavonol Glycosides from Rose Petals Petals from two garden roses proved to be very rich in ellagitannins and flavonol glycosides. Rutin ( 1 ), spiraeoside ( 2 ), quercitrin ( 3 ), isoquercitrin ( 4 ), nicotiflorin ( 5 ), eugeniin ( 6 ), rugosin A (7), rugosin D ( 10 ), casuarictin ( 8 ), and tellimagrandin I (9) were isolated. Spiraeoside, at physiological pH, exerts a pronounced stabilisation of the anthocyanin colour with enhancement of extinction and bathochromic shift of the absorption maximum in the visible range. The abundance of gallic‐acid derivatives 6–10 is in contrast to the apparent inability of rose flowers to produce anthocyanins with a trihydroxylated ring B , a prerequisite in breeding true blue‐coloured roses.