Anthocyanins from the flowers of Nagai line of Japanese garden iris (Iris ensata)

Abstract

Six anthocyanins were isolated from the flowers of the Nagai line of Iris ensata Thunb. They were identified as petunidin and malvidin 3-O-β-[(4‴-Z-p-coumaroyl-α-rhamnopyranosyl)-(1→6) -β-glucopyranoside]-5-O-β-glucopyranosides (1 and 3) and their E-forms (2 and 4 ), and petunidin and malvidin 3-O-rutinoside-5-O-glucosides (5 and 6). Though the E-form of petunidin 3-O-[(4‴-p-coumaroylrhamnosyl)-(1→6) -glucoside]-5-O-glucoside has been reported, its Z-form was found for the first time. The presence of Z- and E-forms of malvidin 3-O-[(4‴-p- coumaroylrhamnosyl)-(1→6)-glucoside]-5-O-glucoside is also reported for the first time. Fifty-one cultivars of Nagai line and their wild form (I. ensata var. spontanea) were divided into four anthocyanin patterns, i.e. 1) the presence of 1-4, 2) the presence of 2 and 4, 3) the presence of 5 and 6, and 4) no anthocyanin.