malvidin-3-glucoside and isovalerylaldehyde

The condensation reaction between malvidin 3-glucoside and catechin mediated by isobutyraldehyde, benzaldehyde, and isovaleraldehyde was conducted in model solutions at two pH values (1.5 and 3.2). The formation of new alkyl/aryl-linked adducts corresponding to the structures malvidin 3-glucoside-isobutylcatechin, malvidin 3-glucoside-benzylcatechin, and malvidin 3-glucoside-3-methylbutylcatechin was respectively observed from each aldehyde. The structural characterization of these new structures has been elucidated by 1D and 2D NMR, mass spectrometry, and UV-vis techniques. These new adducts showed the same lambda(max) in the visible region at 540 nm, which is bathochromically shifted 15 nm when compared with the original anthocyanin (lambda(max) = 525 nm).

Topics: Aldehydes; Anthocyanins; Benzaldehydes; Catechin; Flavonols; Glucosides; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Molecular Structure; Pigments, Biological; Spectrophotometry, Ultraviolet