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.