Flavonols and an indole alkaloid skeleton bearing identical acylated glycosidic groups from yellow petals of Papaver nudicaule

The nudicaulins from yellow petals of Iceland poppy consist of four pairs of isomeric glycosidic compounds differing in the malonylation pattern. The structure of a pentacyclic indole akaloid skeleton was proposed for the aglyca of the major nudicaulins VII and VIII by combining 2D NMR, MS and CD data. In addition, kaempferol derivatives having identical acylated glycoside moieties were identified. From yellow petals of Iceland poppy, besides the known flavonoid gossypitrin, seven kaempferol derivatives were isolated. In addition to kaempferol 3- O-β-sophoroside and kaempferol 3- O-β-sophoroside-7- O-β-glucoside, known from other plants, the mono- and dimalonyl conjugates of the latter were identified by MS and NMR spectroscopy. Structure analyses of a set of co-occurring pigments, the nudicaulins, revealed that they have the identical acylated glycoside moieties attached to a pentacyclic indole alkaloid skeleton for which the structure of 19-(4-hydroxyphenyl)-10 H-1,10-ethenochromeno[2,3- b]indole-6,8,18-triol was deduced from MS and NMR as well as chemical and chiroptical methods.