(Delphinidin 3-gentiobiosyl)(Luteorin 7-glucosyl) malonate from the flowers of eichhornia crassipes

摘要

An additional new pigment exhibiting anthocyanin and flavone disubstituted malonate structure,was isoalted from the blue-purple flowers of Eichhornia crassipes as a minor anthocyanin.This pigment was identified as (6'''-O-(delphinidin 3-O-(6''-O-(beta-D-glucopyranosyl)-beta-D-glucopyranosyl))) (6''-O-(luteolin 7-O-(beta-D-glucopyranosyl))) malonate by chemical and spectroscopic methods.The gammamax of this pigment is 547 nm in 0.1% HCl-MeOH,where the negative cotton effect is also observed as similar to that of Eichhornia anthocyanin A,(delphinidin 3-gentiobiosyl) (apigenin 7-blucosyl) malonate previously isolated from the same flowers.This result supports that the new pigment also takes a folding conformation between delphinidin (chromophore) and luteorin (co-pigmnet).