Coumaric acid

p-Coumaric acid
IUPAC name 3-(4-hydroxyphenyl)-2-propenoic acid
Other names para-coumaric acid, 4-hydroxycinnamic acid, β-(4-hydroxyphenyl)acrylic acid
Identifiers
CAS number	501-98-4 N
PubChem	637542
ChemSpider	553148 Y
EC number	231-000-0
DrugBank	DB04066
ChEBI	CHEBI:32374 Y
ChEMBL	CHEMBL66879 Y
Jmol-3D images	Image 1 Image 2
SMILES C1=CC(=CC=C1\C=C\C(=O)O)O c1cc(ccc1/C=C/C(=O)O)O
InChI InChI=1S/C9H8O3/c10-8-4-1-7(2-5-8)3-6-9(11)12/h1-6,10H,(H,11,12)/b6-3+ Y Key: NGSWKAQJJWESNS-ZZXKWVIFSA-N Y InChI=1/C9H8O3/c10-8-4-1-7(2-5-8)3-6-9(11)12/h1-6,10H,(H,11, 12)/b6-3+/f/h11H InChI=1/C9H8O3/c10-8-4-1-7(2-5-8)3-6-9(11)12/h1-6,10H,(H,11,12)/b6-3+ Key: NGSWKAQJJWESNS-ZZXKWVIFBJ
Properties
Molecular formula	C9H8O3
Molar mass	164.16 g mol−1
Exact mass	164.047344
Melting point	210–213 °C
Hazards
R-phrases	R36/37/38
S-phrases	S24/25
N acid (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Coumaric acid is a hydroxycinnamic acid, an organic compound that is a hydroxy derivative of cinnamic acid. There are three isomers, o-coumaric acid, m-coumaric acid, and p-coumaric acid, that differ by the position of the hydroxy substitution of the phenyl group. p-Coumaric acid is the most abundant isomer of the three in nature.

Together with sinapyl alcohol and coniferyl alcohols, p-coumaric acid is a major component of lignocellulose. It is biosynthesized from cinnamic acid by the action of the P450-dependent enzyme 4-cinnamic acid hydroxylase.

p-Coumaric acid can be found in a wide variety of edible plants such as peanuts, tomatoes, carrots, and garlic. It is a crystalline solid that is slightly soluble in water, but well soluble in ethanol and diethyl ether.

p-Coumaric acid has antioxidant properties and is believed to reduce the risk of stomach cancer^[1] by reducing the formation of carcinogenic nitrosamines.^[2]

Biochemistry

p-Coumaric acid is the precursor of 4-ethylphenol produced by the yeast Brettanomyces in wine. The yeast converts this to 4-vinylphenol via the enzyme cinnamate decarboxylase.^[3] 4-Vinylphenol is further reduced to 4-ethylphenol by the enzyme vinyl phenol reductase. Coumaric acid is sometimes added to microbiological media, enabling the positive identification of Brettanomyces by smell.

The conversion of p-coumaric acid to 4-ethyphenol by Brettanomyces

See also

• Coumaroyl-Coenzyme A
• Ferulic acid
• Cinnamic acid

References

1. ^ Ferguson LR, Shuo-tun Z, Harris PJ (2005). "Antioxidant and antigenotoxic effects of plant cell wall hydroxycinnamic acids in cultured HT-29". Molecular Nutrition & Food Research 49 (6): 585–693. doi:10.1002/mnfr.200500014. PMID 15841493. 
2. ^ Kikugawa K, Hakamada T, Hasunuma M, Kurechi T (1983). "Reaction of p-hydroxycinnamic acid derivatives with nitrite and its relevance to nitrosamine formation". Journal of Agricultural and Food Chemistry 1 (4): 780–785. doi:10.1021/jf00118a025. 
3. ^ Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol at etslabs.com