Caffeic acid

Caffeic acid
Names
	IUPAC names 3-(3,4-Dihydroxyphenyl)-2-propenoic acid; 3,4-Dihydroxycinnamic acid; trans-Caffeate; 3,4-Dihydroxy-trans-cinnamate; (E)-3-(3,4-dihydroxyphenyl)-2-propenoic acid; 3,4-Dihydroxybenzeneacrylicacid; 3-(3,4-Dihydroxyphenyl)-2-propenoic acid
	Preferred IUPAC name (2E)-3-(3,4-Dihydroxyphenyl)prop-2-enoic acid
Identifiers
CAS Number	501-16-6 ; 331-39-5 (non-specific) ;
3D model (JSmol)	Interactive image;
Beilstein Reference	1954563
ChEBI	CHEBI:16433 ;
ChEMBL	ChEMBL145 ;
ChemSpider	600426 ;
DrugBank	DB01880 ;
ECHA InfoCard	100.005.784
EC Number	206-361-2;
IUPHAR/BPS	5155;
KEGG	C01481 ;
PubChem CID	689043;
UNII	U2S3A33KVM ;
CompTox Dashboard (EPA)	DTXSID901316055 DTXSID5020231, DTXSID901316055 ;
	InChI InChI=1S/C9H8O4/c10-7-3-1-6(5-8(7)11)2-4-9(12)13/h1-5,10-11H,(H,12,13)/b4-2+ Key: QAIPRVGONGVQAS-DUXPYHPUSA-N ; InChI=1/C9H8O4/c10-7-3-1-6(5-8(7)11)2-4-9(12)13/h1-5,10-11H,(H,12,13)/b4-2+ Key: QAIPRVGONGVQAS-DUXPYHPUBE;
	SMILES O=C(O)\C=C\c1cc(O)c(O)cc1;
Properties
Chemical formula	C9H8O4
Molar mass	180.16 g/mol
Density	1.478 g/cm3
Melting point	223 to 225 °C (433 to 437 °F; 496 to 498 K)
UV-vis (λmax)	327 nm and a shoulder at c. 295 nm in acidified methanol
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335, H351, H361
Precautionary statements	P201, P202, P261, P264, P271, P280, P281, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
NFPA 704 (fire diamond)	1 1 0
Related compounds
Related compounds	Chlorogenic acid; Cichoric acid; Coumaric acid; Quinic acid
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Caffeic acid is an organic compound with the formula (HO)₂C₆H₃CH=CHCO₂H. It is a polyphenol with a key role in scavenging reactive oxygen species (ROS) generated in energy metabolism. Caffeic acid is also one major polyphenol responsible for maintaining normal levels of nitric oxide (NO) within cells. Caffeic acid is a yellow, solid chemical compound that is structually classified as a hydroxycinnamic acid, and the molecule consists of both phenolic and acrylic functional groups. Caffeic acid is found in all plants as an intermediate in the biosynthesis of lignin, a naturally occurring complex carbohydrate representing the principal components of biomass and its residues. It is chemically unrelated to caffeine; instead, the shared name is related to its presence in coffee.