2′-Hydroxylated 3-Deoxyanthocyanin from the Flowers of Cosmos sulphureus Cultivars

Abstract

A new 3-deoxyanthocyanin was isolated from the orange flowers of Cosmos sulphureus cultivar “Diabolo,” together with known aurone, chalcone, flavone, flavonol, and flavanone. The chemical structure of 3-deoxyanthocyanin was established as 5,7,2′,4′-tetrahydroxyflavylium 4′- O-β-d-glucopyranoside by chemical and spectroscopic methods including UV, FAB MS, and 1H and 13C nuclear magnetic resonance spectroscopy (NMR), and named as cosmonidin 4′- O-glucoside (1a). Other known flavonoids were characterized as sulfuretin 6- O-glucoside (2), butein 4′- O-glucoside (3), quercetin 3- O-glucoside (4), luteolin 7- O-glucuronide (5), and eriodictyol 7- O-glucuronide (6) by UV, liquid chromatograph - mass spectra (LC-MS), NMR, and high performance liquid chromatography comparisons with authentic samples. Anthocyanin, which 2′-position is hydroxylated, has not been reported until now. Compound (1a) was also found in other 10 C. sulphureus cultivars “Lamala Lemon,” “Sunrise,” “Dwarf Yellow,” “Cosmic Yellow,” “Carpet Gold,” “Mandarin,” “Cosmic Orange,” “Orange Flare,” “Cosmic Red,” and “Sunset.”