p-Coumaric acid

p-Coumaric acid

Names
IUPAC name (E)-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
ChEBI	CHEBI:32374
ChEMBL	ChEMBL66879
ChemSpider	553148
DrugBank	DB04066
EC Number	231-000-0
IUPHAR/BPS	5787
Jmol interactive 3D	Image Image
PubChem	637542
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+ Key: NGSWKAQJJWESNS-ZZXKWVIFSA-N 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
SMILES C1=CC(=CC=C1\C=C\C(=O)O)O c1cc(ccc1/C=C/C(=O)O)O
Properties
Chemical formula	C9H8O3
Molar mass	164.16 g·mol^−1
Melting point	210 to 213 °C (410 to 415 °F; 483 to 486 K)
Hazards
R-phrases	R36/37/38
S-phrases	S24/25
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

p-Coumaric acid is a hydroxycinnamic acid, an organic compound that is a hydroxy derivative of cinnamic acid. There are three isomers of coumaric acid—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. p-Coumaric acid exists in two forms trans-p-coumaric acid and cis-p-coumaric acid.

It is a crystalline solid that is slightly soluble in water, but well soluble in ethanol and diethyl ether.

Together with sinapyl alcohol and coniferyl alcohols, p-coumaric acid is a major component of lignin.

Natural occurrences

p-Coumaric acid can be found in Gnetum cleistostachyum.^[1]

in food

p-Coumaric acid can be found in a wide variety of edible plants such as peanuts, navy beans, tomatoes, carrots, and garlic. It is found in wine and vinegar.^[2] It is also found in barley grain.^[3]

p-Coumaric acid from pollen is a constituent of honey.^[4]

Derivatives

p-Coumaric acid glucoside can also be found in commercial breads containing flaxseed.^[5]

Diesters of p-coumaric acid can be found in carnauba wax.

Metabolism

Biosynthesis

It is biosynthesized from cinnamic acid by the action of the P450-dependent enzyme 4-cinnamic acid hydroxylase (C4H).

 $\xrightarrow{C4H}$ 

It is also produced from L-tyrosine by the action of tyrosine ammonia lyase (TAL).

 $\xrightarrow{TAL}$  + Ammonia + H⁺

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.^[6] 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

cis-p-coumarate glucosyltransferase is an enzyme that uses UDP-glucose and cis-p-coumarate to produce 4'-O-beta-D-glucosyl-cis-p-coumarate and UDP. This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases.^[7]

Phloretic acid is found in the rumen of sheep fed with dried grass and is produced by hydrogenation of the 2-propenoic side chain of p-coumaric acid.^[8]

Medicinal uses

p-Coumaric acid has antioxidant properties and is believed to reduce the risk of stomach cancer^[9] by reducing the formation of carcinogenic nitrosamines.^[10]

Biological Effects

p-Coumaric acid is normally present in honey, but not in the substitute nutrients based on high-fructose corn syrup that honey bee keepers feed to their colonies. This absence has been suggested as a possible contributor to Colony Collapse Disorder of honey bees because p-coumaric acid has been found to help honey bees detoxify certain pesticides.^[4]

See also

• Coumarin
• Coumaroyl-Coenzyme A
• Ferulic acid
• Cinnamic acid
• Phenolic content in wine
• p-Coumaroylated anthocyanins

References

1. Yao, Chun-Suo; Lin, Mao; Liu, Xin; Wang, Ying-Hong (2005). "Stilbene derivatives from Gnetum cleistostachyum". Journal of Asian Natural Products Research 7 (2): 131–7. doi:10.1080/10286020310001625102. PMID 15621615.
2. Gálvez, Miguel Carrero; Barroso, Carmelo García; Pérez-Bustamante, Juan Antonio (1994). "Analysis of polyphenolic compounds of different vinegar samples". Zeitschrift für Lebensmittel-Untersuchung und -Forschung 199: 29–31. doi:10.1007/BF01192948.
3. Quinde-Axtell, Zory; Baik, Byung-Kee (2006). "Phenolic Compounds of Barley Grain and Their Implication in Food Product Discoloration". Journal of Agricultural and Food Chemistry 54 (26): 9978–84. doi:10.1021/jf060974w. PMID 17177530.
4. Mao W, Schuler M A, Berenbaum M R (2013). "Honey constituents up-regulate detoxification and immunity genes in the western honey bee Apis mellifera". Proceedings of the National Academy of Sciences of the United States of America 110 (April 29, 2013): 8842–6. doi:10.1073/pnas.1303884110. PMC 3670375. PMID 23630255.
5. Strandås, C.; Kamal-Eldin, A.; Andersson, R.; Åman, P. (2008). "Phenolic glucosides in bread containing flaxseed". Food Chemistry 110 (4): 997–999. doi:10.1016/j.foodchem.2008.02.088.
6. Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol at etslabs.com
7. Rasmussen, Susanne; Rudolph, Hansjörg (1997). "Isolation, purification and characterization of UDP-glucose: Cis-p-coumaric acid-β-d-glucosyltransferase from sphagnum fallax". Phytochemistry 46 (3): 449–453. doi:10.1016/S0031-9422(97)00337-3.
8. Chesson, A; Stewart, CS; Wallace, RJ (1982). "Influence of plant phenolic acids on growth and cellulolytic activity of rumen bacteria". Applied and Environmental Microbiology 44 (3): 597–603. PMC 242064. PMID 16346090.
9. 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.
10. 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.