Oenin
Chemical compound / From Wikipedia, the free encyclopedia
Oenin is an anthocyanin. It is the 3-glucoside of malvidin. It is one of the red pigments found in the skin of purple grapes[1] and in wine.[2]
Names | |
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IUPAC name
3-(β-D-Glucopyranosyloxy)-4′,5,7-trihydroxy-3′,5′-dimethoxyflavylium | |
Systematic IUPAC name
5,7-Dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-3-{[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}-1λ4-benzopyran-1-ylium | |
Other names
Enin Malvidin-3-glucoside Malvidin 3-O-glucoside | |
Identifiers | |
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ECHA InfoCard | 100.027.847 |
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Properties | |
C23H25O12+, C23H25ClO12 (chloride) | |
Molar mass | 493.43 g/mol, 528.89 g/mol (chloride) |
Appearance | dark brown powder (chloride) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Color stabilization of malvidin 3-glucoside at a higher pH can be explained by self-aggregation of the flavylium cation and copigmentation with the Z-chalcone form.[3] In the presence of procyanidin C2, the red color of oenin appears more stable. However, the HPLC chromatogram shows a decrease in the amplitude of the peaks of oenin and procyanidin C2. Concomitantly, a new peak appears with a maximal absorption in the red region. This newly formed pigment probably comes from the condensation of oenin and procyanidin C2.[4]
Malvidin 3-glucoside alone is not oxidized in the presence of grape polyphenol oxidase, whereas it is degraded in the presence of a crude grape PPO extract and of caftaric acid forming anthocyanidin-caftaric acid adducts.[5]