Seven acylated anthocyanins in blue flowers of Gentiana

Abstract

Three novel anthocyanins, delphinidin 3,3′- di-O-β- d-glucoside -5-O-(6-O- caffeoyl-β- d-glucoside ) , delphinidin 3,3′- di-O-β- d-glucoside -5-O-(6-O-trans-p- coumaroyl-β- d-glucoside ) and delphinidin 3-O-β- d-glucoside -5-O-(6-O-trans-p- coumaroyl-β- d-glucoside ) , named albireodelphin A, B and C, respectively, were isolated from the blue flowers of Gentiana cv. Albireo, along with two known anthocyanins, gentiodelphin and gentiocyanin A. The complete structure of each anthocyanin was unambiguously determined by one- and two-dimensional NMR and other spectral methods. Two other novel anthocyanins, delphinidin 3-O-β- d-glucoside -5-O-(6-O- caffeoyl-β- d- glucoside )-3′-O-(6-O-trans-p- coumaroyl-β- d-glucoside ) and dephinidin 3-O-β- d-glucoside -5-O-(6-O-trans-p- coumaroyl-β- d-glucoside )-3′-O-(6-O- caffeoyl-β- d-glucoside ) , named albireodelphin D and E, respectively, were obtained as a mixture and the structures estimated by one- and two-dimensional NMR and other spectral methods.