Oenin

Oenin is an anthocyanin. It is the 3-O-glucoside of malvidin (malvidin-3-O-glucoside). It is one of the red pigments found in purple grape skins and red wine.^[1][2]

Oenin

Names
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
CAS Number	7228-78-6 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL403236 N ChEMBL602754 N
ChemSpider	391785 N
ECHA InfoCard	100.027.847
KEGG	C12140 Y
PubChem CID	443652
UNII	B34F52D7NB Y
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 N Key: PXUQTDZNOHRWLI-OXUVVOBNSA-O N 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). N verify (what is YN ?) Infobox references

UV visible spectrum of malvidin 3-O-glucoside.

Color stabilization of oenin 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]

Oenin 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