Flavonoids in the red-purple flowers of Vicia sativa L. subsp. nigra (L.) Ehrh. (Leguminosae)

The previously undescribed anthocyanin; malvidin 3,5-di- O -(6- O -malonyl)-β-glucopyranoside and the undescribed flavonol; kaempferol 3- O -(6- O -β-xylopyranosyl)-β-glucopyranoside were isolated from the red-purple flowers of Vicia sativa L. subsp. nigra (L.) Ehrh. Additionally, four known flavonols were identified: quercetin 3- O -(6- O -β-xylopyranosyl)-β-glucopyranoside, kaempferol 3- O -(6- O -α-rhamnopyranosyl)-β-glucopyranoside, quercetin 3- O -(6- O -α-rhamnopyranosyl)-β-glucopyranoside, and kaempferol 3- O -(2,6-di- O -α-rhamnopyranosyl)-β-glucopyranoside. Structural identification of these flavonoids was achieved through nuclear magnetic resonance spectroscopy and mass spectrometry. Additionally, six known anthocyanins; specifically the 3,5-di- O -glucosides and 3- O -glucoside-5- O -(6- O -malonyl)-glucosides of delphinidin, petunidin, and malvidin, were identified in the flowers (vexillum and wing). • Seven anthocyanins and five flavonols were identified from the flowers of Vicia sativa subsp. nigra. • The structures were elucidated on the basis of chemical and spectroscopic data. • One anthocyanin and one flavonol were identified for the first time.