Oenin

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]

Oenin

Names
IUPAC name (2S,3R,4S,5S,6R)-2-[5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)chromenylium-3-yl]oxy-6-(hydroxymethyl)oxane-3,4,5-triol
Other names Enin Malvidin-3-glucoside Malvidin 3-O-glucoside
Identifiers
CAS Number	7228-78-6
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL403236 ChEMBL602754
ChemSpider	391785
ECHA InfoCard	100.027.847
PubChem CID	443652
UNII	B34F52D7NB
CompTox Dashboard (EPA)	DTXSID30332124
InChI InChI=1S/C23H24O12/c1-31-14-3-9(4-15(32-2)18(14)27)22-16(7-11-12(26)5-10(25)6-13(11)33-22)34-23-21(30)20(29)19(28)17(8-24)35-23/h3-7,17,19-21,23-24,28-30H,8H2,1-2H3,(H2-,25,26,27)/p+1/t17-,19-,20+,21-,23-/m1/s1 Key: PXUQTDZNOHRWLI-OXUVVOBNSA-O InChI=1/C23H24O12/c1-31-14-3-9(4-15(32-2)18(14)27)22-16(7-11-12(26)5-10(25)6-13(11)33-22)34-23-21(30)20(29)19(28)17(8-24)35-23/h3-7,17,19-21,23-24,28-30H,8H2,1-2H3,(H2-,25,26,27)/p+1/t17-,19-,20+,21-,23-/m1/s1 Key: PXUQTDZNOHRWLI-JIKKCJRGBW
SMILES COC1=CC(=CC(=C1O)OC)C2=C(C=C3C(=CC(=CC3=[O+]2)O)O)OC4C(C(C(C(O4)CO)O)O)O
Properties
Chemical formula	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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Infobox references

UV visible spectrum of malvidin 3-O-glucoside.

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]

See also

• Phenolic compounds in wine
• Wine color
• Malvidin glucoside-ethyl-catechin
• Anthocyanone A, a degradation product of oenin found in wine

References

1. Oenin on answers.com
2. Di Justo, Patrick (Aug 30, 2011). "What's Inside: Red Wine". Wired. Condé Nast.
3. Houbiers, Chantal; Lima, João C.; Maçanita, António L.; Santos, Helena (1998). "Color Stabilization of Malvidin 3-Glucoside: Self-Aggregation of the Flavylium Cation and Copigmentation with the Z-Chalcone Form". The Journal of Physical Chemistry B. 102 (18): 3578. doi:10.1021/jp972320j.
4. Malien-Aubert, C; Dangles, O; Amiot, MJ (2002). "Influence of procyanidins on the color stability of oenin solutions". Journal of Agricultural and Food Chemistry. 50 (11): 3299–305. doi:10.1021/jf011392b. PMID 12010001.
5. Sarni-Manchado, Pascale; Cheynier, Véronique; Moutounet, Michel (1997). "Reactions of polyphenoloxidase generated caftaric acid o-quinone with malvidin 3-O-glucoside". Phytochemistry. 45 (7): 1365. doi:10.1016/S0031-9422(97)00190-8.