P-Coumaric acid

p-Coumaric acid is an organic compound with the formula HOC₆H₄CH=CHCO₂H. It is one of the three isomers of coumaric acid. It is a white solid that is only slightly soluble in water but very soluble in ethanol and diethyl ether.

p-Coumaric acid

Skeletal formula of p-coumaric acid
Ball-and-stick model of 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 trans-4-Hydroxycinnamic acid β-(4-Hydroxyphenyl)acrylic acid
Identifiers
CAS Number	501-98-4 Y
3D model (JSmol)	Interactive image Interactive image
Beilstein Reference	2207383
ChEBI	CHEBI:32374 Y
ChEMBL	ChEMBL66879 Y
ChemSpider	553148 Y
DrugBank	DB04066 Y
ECHA InfoCard	100.116.210
EC Number	231-000-0
Gmelin Reference	2245630
IUPHAR/BPS	5787
KEGG	C00811
PubChem CID	637542
UNII	IBS9D1EU3J
CompTox Dashboard (EPA)	DTXSID30901076
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
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	164.160 g·mol−1
Melting point	210 to 213 °C (410 to 415 °F; 483 to 486 K)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H302, H311, H314, H315, H317, H319, H335
Precautionary statements	P260, P261, P264, P270, P271, P272, P280, P301+P310, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P332+P313, P333+P313, P337+P313, P361, P362, P363, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Natural occurrences

It is a precursor to many natural products, especially lignols, precursors to the woody mass that comprise many plants.^[1] Of the myriad occurrences, p-coumaric acid can be found in Gnetum cleistostachyum.^[2]

In food

p-Coumaric acid can be found in a wide variety of edible plants and fungi such as peanuts, navy beans, tomatoes, carrots, basil and garlic.^{[citation needed]} It is found in wine and vinegar.^[3] It is also found in barley grain.^[4]

p-Coumaric acid from pollen is a constituent of honey.^[5]

Derivatives

p-Coumaric acid glucoside can also be found in commercial breads containing flaxseed.^[6] Diesters of p-coumaric acid can be found in carnauba wax.

Biosynthesis

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

 ${\displaystyle {\begin{matrix}{}\\{\xrightarrow {\mathrm {C4H} }}\\{}\end{matrix}}}$ 

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

 ${\displaystyle {\xrightarrow {\mathrm {TAL} }}}$  + NH₃ + H⁺

Biosynthetic building block

p-Coumaric acid is the precursor of 4-ethylphenol produced by the yeast Brettanomyces in wine. The enzyme cinnamate decarboxylase catalyzes the conversion of p-coumaric acid into 4-vinylphenol.^[7] Vinyl phenol reductase then catalyzes the reduction of 4-vinylphenol to 4-ethylphenol. 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.^[8]

Phloretic acid, found in the rumen of sheep fed with dried grass, is produced by hydrogenation of the 2-propenoic side chain of p-coumaric acid.^[9]

The enzyme, resveratrol synthase, also known as stilbene synthase, catalyzes the synthesis of resveratrol ultimately from a tetraketide derived from 4-coumaroyl CoA.^[10]

p-Coumaric acid is a cofactor of photoactive yellow proteins (PYP), a homologous group of proteins found in many eubacteria.^[11]

p-Coumaric acid is found as the base moiety of caleicine, one of many sesquiterpenes in Calea ternifolia.

See also

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