''p''-Coumaric acid

p-Coumaric acid
Names
Preferred IUPAC name
(2E)-3-(4-Hydroxyphenyl)prop-2-enoic acid
Other names
(E)-3-(4-Hydroxyphenyl)-2-propenoic acid
(E)-3-(4-Hydroxyphenyl)acrylic acid
para-Coumaric acid
4-Hydroxycinnamic acid
β-(4-Hydroxyphenyl)acrylic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.116.210
EC Number 231-000-0
Properties
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R-phrases (outdated) R36/37/38
S-phrases (outdated) S24/25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 very soluble in ethanol and diethyl ether.

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, basil 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).

   

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

    + NH3 + 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 uridine diphosphate glucose and cis-p-coumarate to produce 4′-O-β-D-glucosyl-cis-p-coumarate and uridine diphosphate (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]

See also

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): 131–137. doi:10.1080/10286020310001625102. PMID 15621615.
  2. ↑ Carrero Gálvez, Miguel; García Barroso, Carmelo; 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): 9978–9984. 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: 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". etslabs.com. Archived from the original on 2008-02-19.
  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, C. S.; Wallace, R. J. (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.
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