Two novel blue pigments with ellagitannin moiety, rosacyanins A1 and A2, isolated from the petals of Rosa hybrida

Two novel blue pigments, rosacyanins A1 and A2, were isolated from the petals of Rosa hybrida cv. ‘M'me. Violet’. Their structures were elucidated on the basis of high-resolution Fourier transform ion cyclotron resonance mass spectroscopy (HR-FT-ICR-MS), FABMS/MS/MS, ¹H, ¹³C and two-dimensional NMR. The molecular formulas of rosacyanin A1 (1) and A2 (2) are C₅₆H₃₇O₃₁ and C₆₃H₄₁O₃₅, respectively. The structures of rosacyanins A1 and A2 consisted of a common chromophore containing cyanidin with a galloyl group link between positions 4 and 5 of the hydroxyl group of the flavylium nucleus and tellimagrandins (1 or 2). These pigments in which anthocyanidin nuclei linked to ellagitannin through an ether bond are the first compounds isolated from natural sources.