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 plays a key role in scavenging reactive oxygen species (ROS) generated in energy metabolism. Caffeic acid is also responsible for maintaining normal levels of nitric oxide (NO) within cells. Caffeic acid is a yellow, solid chemical compound that is structurally 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.