Structural characterization of new malvidin 3-glucoside-catechin aryl/alkyl-linked pigments.
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).
Faculdade de Ciências, Departamento de Química, Universidade do Porto, Centro de Investigação em Química, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
João
J
Pissarra
Sandra
S
Lourenço
Ana M
AM
González-Paramás
Nuno
N
Mateus
Celestino
C
Santos Buelga
Artur M S
AM
Silva
Victor
V
de Freitas
D000447:Aldehydes / Q000737:chemistry; D000872:Anthocyanins / Q000737:chemistry*; D001547:Benzaldehydes / Q000737:chemistry; D002392:Catechin / Q000737:chemistry*; D044948:Flavonols / Q000737:chemistry; D005960:Glucosides; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010860:Pigments, Biological / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D000447:Aldehydes; D000872:Anthocyanins; D001547:Benzaldehydes; D044948:Flavonols; D005960:Glucosides; D010860:Pigments, Biological; C032251:isovalerylaldehyde; C458419:malvidin-3-glucoside; D002392:Catechin; C017439:isobutyraldehyde; C032175:benzaldehyde