Content deleted Content added
m →Other uses: HTTP to HTTPS for Blogspot |
|||
| (344 intermediate revisions by more than 100 users not shown) | |||
Line 1:
{{Chembox
| Watchedfields = changed
| verifiedrevid = 443671399
| Name = Caffeic acid
| ImageFile1 = Kaffeesäure.svg
| ImageName1 = 2D diagram of caffeic acid
| ImageFile2 = Cafeic-acid-3D.png
| ImageName2 = 3D ball-and-stick model of caffeic acid
| ImageFile3 = CaffeicAcid3d.png
| ImageName3 = 3D space filling model of caffeic acid
| PIN = (2''E'')-3-(3,4-Dihydroxyphenyl)prop-2-enoic acid
| IUPACName = 3-(3,4-Dihydroxyphenyl)-2-propenoic acid<br />3,4-Dihydroxycinnamic acid<br />''trans''-Caffeate<br />3,4-Dihydroxy-''trans''-cinnamate<br/>(''E'')-3-(3,4-dihydroxyphenyl)-2-propenoic acid<br />3,4-Dihydroxybenzeneacrylicacid<br />3-(3,4-Dihydroxyphenyl)-2-propenoic acid
|Section1={{Chembox Identifiers
| IUPHAR_ligand = 5155
| Beilstein = 1954563
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 16433
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB01880
| SMILES = O=C(O)\C=C\c1cc(O)c(O)cc1
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 600426
| PubChem = 689043
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 145
| EC_number = 206-361-2
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = U2S3A33KVM
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C01481
| 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+
| InChIKey = QAIPRVGONGVQAS-DUXPYHPUBE
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 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+
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = QAIPRVGONGVQAS-DUXPYHPUSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 501-16-6
| CASNo1_Ref = {{cascite|correct|CAS}}
| CASNo1 = 331-39-5
| CASNo1_Comment = (non-specific)
}}
|Section2 = {{Chembox Properties
| Formula = C<sub>9</sub>H<sub>8</sub>O<sub>4</sub>
| MolarMass = 180.16 g/mol
| Density = 1.478 g/cm<sup>3</sup>
| MeltingPtC = 223 to 225
| BoilingPt =
| LambdaMax = 327 nm and a shoulder at c. 295 nm in acidified methanol<ref>{{cite journal | title = Functional role of anthocyanins in the leaves of ''Quintinia serrata'' A. Cunn. |first1=Kevin S. |last1=Gould |first2=Kenneth R. |last2=Markham |first3=Richard H. |last3=Smith |first4=Jessica J. |last4=Goris | journal = Journal of Experimental Botany | volume = 51 | issue = 347 | pages = 1107–1115 | year = 2000 | doi = 10.1093/jexbot/51.347.1107 | pmid = 10948238| doi-access = free }}</ref>
}}
|Section5={{Chembox Hazards
| NFPA-H = 1
| NFPA-F = 1
| NFPA-R = 0
| GHSPictograms = {{GHS07}}{{GHS08}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|315|319|335|351|361}}
| PPhrases = {{P-phrases|201|202|261|264|271|280|281|302+352|304+340|305+351+338|308+313|312|321|332+313|337+313|362|403+233|405|501}}
}}
|Section8 = {{Chembox Related
| OtherCompounds = [[Chlorogenic acid]]<br/>[[Cichoric acid]]<br/>[[Coumaric acid]]<br/>[[Quinic acid]]
}}
}}
'''Caffeic acid''' is an [[organic compound]] with the formula {{chem2|(HO)2C6H3CH\dCHCO2H}}. 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 [[Phenols|phenolic]] and [[Acrylic acid|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.<ref name=Boerjan/> It is chemically unrelated to [[caffeine]]; instead, the shared name is related to its presence in [[coffee]].
== Natural occurrences ==
Caffeic acid can be found in the bark of ''[[Eucalyptus globulus]]''<ref>{{Cite journal|pmid=21761864|doi=10.1021/jf201801q|title=Characterization of Phenolic Components in Polar Extracts of Eucalyptus globulus Labill. Bark by High-Performance Liquid Chromatography–Mass Spectrometry|year=2011|last1=Santos|first1=Sónia A. O.|last2=Freire|first2=Carmen S. R.|last3=Domingues|first3=M. Rosário M.|last4=Silvestre|first4=Armando J. D.|last5=Pascoal Neto|first5=Carlos|journal=Journal of Agricultural and Food Chemistry|volume=59|issue=17|pages=9386–9393 |bibcode=2011JAFC...59.9386S }}</ref> the [[barley]] grain ''Hordeum vulgare'' and the herb ''[[Dipsacus]] asperoides''.<ref>{{Cite journal|title=The Liquid Chromatographic Determination of Chlorogenic and Caffeic Acids in Xu Duan (Dipsacus asperoides) Raw Herb|last1=Khoo|first1=Cheang S.|last2=Sullivan|first2=Shaun|date=2014|journal=ISRN Analytical Chemistry|language=en|last3=Kazzem|first3=Magdy|last4=Lamin|first4=Franklin|last5=Singh|first5=Swastika|last6=Nang|first6=Marnilar|last7=Low|first7=Mitchell|last8=Suresh|first8=Harsha|last9=Lee|first9=Samiuela|volume=2014|pages=1–6|doi=10.1155/2014/968314|doi-access=free}}</ref> It can also be found in the freshwater fern ''[[Salvinia molesta]]''<ref>{{cite journal|pmid=18177906|doi=10.1016/j.phytochem.2007.10.028|title=Phenolic and other constituents of fresh water fern ''Salvinia molesta''|year=2008|last1=Choudhary|first1=M. Iqbal|last2=Naheed|first2=Nadra|last3=Abbaskhan|first3=Ahmed|last4=Musharraf|first4=Syed Ghulam|last5=Siddiqui|first5=Hina|last6=Atta-Ur-Rahman|journal=Phytochemistry|volume=69|issue=4|pages=1018–1023|bibcode=2008PChem..69.1018C }}</ref> and in the mushroom ''[[Phellinus linteus]]''.<ref name="pmid18827365">{{cite journal|doi=10.1248/bpb.31.1968 |last1=Lee |first1=Y.-S. |title=Protein glycation inhibitors from the fruiting body of ''Phellinus linteus'' |journal=Biological & Pharmaceutical Bulletin |volume=31 |issue=10 |pages=1968–1972 |date=October 2008 |pmid=18827365 |last2=Kang |first2=Y.-H. |last3=Jung |first3=J.-Y. |last4=Lee |first4=Sanghyun |last5=Ohuchi |first5=Kazuo |last6=Shin |first6=Kuk Hyun |last7=Kang |first7=Il-Jun |last8=Park |first8=Jung Han Yoon |last9=Shin |first9=Hyun-Kyung |last10=Soon |first10=Sung |doi-access=free }}</ref>
=== Occurrences in food ===
Free caffeic acid can be found in a variety of beverages, including brewed [[coffee]] at 63.1-96.0 mg per 100 ml<ref>{{cite journal|title=Determination of free and total phenolic acids in plant-derived foods by HPLC with diode-array detection|first1=Mittila|last1=Pirjo|first2=Jorma|last2=Kumpulainen|date=19 June 2002|journal=J Agric Food Chem|volume=50|issue=13 |pages=3660–7|doi=10.1021/jf020028p|pmid= 12059140 |bibcode=2002JAFC...50.3660M }}</ref> and red wine at 2 mg per 100 ml.<ref>{{cite web | url=http://phenol-explorer.eu/contents/polyphenol/457 | title=Showing all foods in which the polyphenol Caffeic acid is found - Phenol-Explorer }}</ref> It is found at relatively high levels in herbs of the mint family, especially [[thyme]], [[Salvia officinalis|sage]] and [[spearmint]] (at about 20 mg per 100 g), and in spices, such as [[Cinnamomum verum|Ceylon cinnamon]] and [[Illicium verum|star anise]] (at about 22 mg per 100 g). Caffeic acid occurs at moderate levels in [[sunflower seed]]s (8 mg per 100 g), [[apple sauce]], [[apricot]]s and [[prune]]s (at about 1 mg per 100 g).<ref>{{cite journal | url=https://www.ncbi.nlm.nih.gov/books/NBK513593/ | pmid=8411618 | year=1993 | title=Caffeic acid | journal=Iarc Monographs on the Evaluation of Carcinogenic Risks to Humans | volume=56 | pages=115–134 | pmc=7681336 }}</ref> It occurs at remarkably high levels in [[Aronia melanocarpa|black chokeberry]] (141 mg per 100 g).<ref>{{cite journal|title=Oxygen radical absorbing capacity of phenolics in blueberries, cranberries, chokeberries, and lingonberries|first1=Wei|last1=Zheng|first2=Shiow Y|last2=Wang|date=15 January 2003|journal=J Agric Food Chem|volume=51|issue=2 |pages=502–9|doi=10.1021/jf020728u|pmid= 12517117 |bibcode=2003JAFC...51..502Z }}</ref> It is also quite high in the South American herb [[yerba mate]] (150 mg per 100 g based on [[thin-layer chromatography]] [[densitometry]]<ref>{{cite journal|title=Determination of Flavonoids, Phenolic Acids, and Xanthines in Mate Tea (''Ilex paraguariensis'' St.-Hil.)|first1=Mirza|last1=Bojić|first2=Vicente Simon|last2=Haas|first3=Darija|last3=Šarić|first4=Željan|last4=Maleš|date=4 April 2018|journal=Journal of Analytical Methods in Chemistry|volume=2013|pages=658596|doi=10.1155/2013/658596|pmid=23841023|pmc=3690244|doi-access=free}}</ref> and HPLC <ref>{{cite journal|doi=10.1021/jf2008343 | pmid=21510640 | volume=59 | issue=10 | title=Chemical Composition and Antioxidant Activity of Yerba-Mate (''Ilex paraguariensis'' A. St.-Hil., Aquifoliaceae) Extract as Obtained by Spray Drying | journal=Journal of Agricultural and Food Chemistry | pages=5523–5527 | last1 = Berté | first1 = Kleber A. S.| year=2011 | bibcode=2011JAFC...59.5523B }}</ref>). It is also found at lower levels in [[barley]] and [[rye]].<ref>{{cite journal | last1 = Quinde-Axtell | first1 = Zory | last2 = Baik | first2 = Byung-Kee | year = 2006 | title = Phenolic Compounds of Barley Grain and Their Implication in Food Product Discoloration | journal = J. Agric. Food Chem. | volume = 54 | issue = 26 | pages = 9978–9984 | doi = 10.1021/jf060974w | pmid=17177530 | bibcode = 2006JAFC...54.9978Q }}</ref>
=== Biosynthesis ===
Caffeic acid is biosynthesized by [[hydroxylation]] of [[coumaric acid|coumaroyl]] ester of [[Chlorogenic acid|quinic acid]] (esterified through a side chain alcohol). This hydroxylation produces the caffeic acid ester of [[shikimic acid]], which converts to [[chlorogenic acid]]. It is the precursor to [[ferulic acid]], [[coniferyl alcohol]], and [[sinapyl alcohol]], all of which are significant building blocks in lignin.<ref name=Boerjan>{{cite journal|doi=10.1146/annurev.arplant.54.031902.134938|title=Lignin biosynthesis|year=2003|last1=Boerjan|first1=Wout|last2=Ralph|first2=John|last3=Baucher|first3=Marie|journal=Annual Review of Plant Biology|volume=54|issue=1 |pages=519–546|pmid=14503002|bibcode=2003AnRPB..54..519B |url=https://biblio.ugent.be/publication/211742/file/4144786|url-access=subscription}}</ref> The transformation to ferulic acid is catalyzed by the [[enzyme]] [[Caffeate O-methyltransferase|caffeate ''O''-methyltransferase]].
Caffeic acid and its derivative [[caffeic acid phenethyl ester]] (CAPE) are produced in many kinds of plants.<ref>{{cite web|url=http://indigo-herbs.co.uk/acatalog/Red_Clover_Flowers_Info.html|title=Red Clover Benefits & Information|website=indigo-herbs.co.uk|access-date=4 April 2018}}</ref><ref name="urlActivities of a Specific Chemical Query">{{cite web |url=http://www.ars-grin.gov/cgi-bin/duke/chemical.pl?CAFFEICACID |title=Dr. Duke's Phytochemical and Ethnobotanical Databases |archive-url=https://web.archive.org/web/20001205192000/http://www.ars-grin.gov/cgi-bin/duke/chemical.pl?CAFFEICACID |archive-date=2000-12-05 |url-status=dead }}</ref><ref name="pmid11208940"/>
:[[Image:CaffeicAcIn.png|thumb|300px|left|In plants, caffeic acid (middle) is formed from 4-hydroxycinnamic acid (left) and is transformed to [[ferulic acid]].]]
{{clear left}}
Dihydroxyphenylalanine ammonia-lyase was presumed to use [[L-DOPA|3,4-dihydroxy-<small>L</small>-phenylalanine]] (<small>L</small>-DOPA) to produce trans-caffeate and NH<sub>3</sub>. However, the EC number for this purported enzyme was deleted in 2007, as no evidence has emerged for its existence.<ref>{{cite web|url=http://www.chem.qmul.ac.uk/iubmb/enzyme/EC4/3/1/11.html|title=EC 4.3.1.11|website=www.chem.qmul.ac.uk|access-date=4 April 2018|archive-url=https://web.archive.org/web/20160303180117/http://www.chem.qmul.ac.uk/iubmb/enzyme/EC4/3/1/11.html|archive-date=3 March 2016|url-status=dead}}</ref>
=== Biotransformation ===
[[Caffeate O-methyltransferase|Caffeate ''O''-methyltransferase]] is an enzyme responsible for the transformation of caffeic acid into [[ferulic acid]].
Caffeic acid and related ''o''-diphenols are rapidly oxidized by [[O-Diphenol oxidase|''o''-diphenol oxidases]] in tissue extracts.<ref>{{cite journal | last1 = Pierpoint | first1 = W. S. | year = 1969 | title = ''o''-Quinones formed in plant extracts. Their reactions with amino acids and peptides | journal = Biochem. J. | volume = 112 | issue = 5| pages = 609–616 | doi=10.1042/bj1120609| pmid = 4980678 | pmc = 1187763 }}</ref>
=== Biodegradation ===
[[Caffeate 3,4-dioxygenase]] is an enzyme that uses caffeic acid and oxygen to produce [[3-(2-carboxyethenyl)-cis,cis-muconate|3-(2-carboxyethenyl)-''cis'',''cis''-muconate]].
Caffeic acid is susceptible to [[autoxidation]]. [[Glutathione]] and [[thiol]] compounds ([[cysteine]], [[thioglycolic acid]] or [[thiocresol]]) or [[ascorbic]] acid have a protective effect on browning and disappearance of caffeic acid.<ref>{{cite journal | last1 = Cilliers | first1 = Johannes J. L. | last2 = Singleton | first2 = Vernon L. | year = 1990 | title = Caffeic acid autoxidation and the effects of thiols | journal = J. Agric. Food Chem. | volume = 38 | issue = 9| pages = 1789–1796 | doi = 10.1021/jf00099a002 | bibcode = 1990JAFC...38.1789C }}</ref> This browning is due to the conversion of [[o-diphenol|''o''-diphenols]] into reactive [[o-quinone|''o''-quinone]]s. Chemical oxidation of caffeic acid in acidic conditions using [[sodium periodate]] leads to the formation of dimers with a furan structure (isomers of 2,5-(3′,4′-dihydroxyphenyl)tetrahydrofuran 3,4-dicarboxylic acid).<ref>{{cite journal | last1 = Fulcrand | first1 = Hélène | last2 = Cheminat | first2 = Annie | last3 = Brouillard | first3 = Raymond | last4 = Cheynier | first4 = Véronique | year = 1994 | title = Characterization of compounds obtained by chemical oxidation of caffeic acid in acidic conditions | journal = Phytochemistry | volume = 35 | issue = 2| pages = 499–505 | doi = 10.1016/S0031-9422(00)94790-3 | bibcode = 1994PChem..35..499F }}</ref> Caffeic acid can also be polymerized using the [[horseradish peroxidase]]/[[hydrogen peroxide|H<sub>2</sub>O<sub>2</sub>]] oxidizing system.<ref>{{cite journal | last1 = Xu | first1 = Peng | last2 = Uyama | first2 = Hiroshi | last3 = Whitten | first3 = James E. | last4 = Kobayashi | first4 = Shiro |author5-link=David L. Kaplan (engineer) | last5 = Kaplan | first5 = David L. | year = 2005 | title = Peroxidase-Catalyzed in Situ Polymerization of Surface Orientated Caffeic Acid | journal = J. Am. Chem. Soc. | volume = 127 | issue = 33| pages = 11745–11753 | doi = 10.1021/ja051637r | pmid=16104752 | bibcode = 2005JAChS.12711745X }}</ref>
== Glycosides ==
[[3-O-caffeoylshikimic acid|3-''O''-caffeoylshikimic acid]] ([[dactylifric acid]]) and its isomers, are [[enzymic browning]] substrates found in dates (''[[Phoenix dactylifera]]'' fruits).<ref>{{Cite journal|pmid=5836492|year=1964|last1=Maier|first1=V. P.|last2=Metzler|first2=D. M.|last3=Huber|first3=A. F.|title=3-''O''-Caffeoylshikimic acid (dactylifric acid) and its isomers, a new class of enzymic browning substrates|volume=14|issue=2|pages=124–128|journal=Biochemical and Biophysical Research Communications|doi=10.1016/0006-291x(64)90241-4 |bibcode=1964BBRC...14..124M }}</ref>
== Pharmacology ==
Caffeic acid has a variety of potential pharmacological effects in ''[[in vitro]]'' studies and in animal models, and the inhibitory effect of caffeic acid on cancer cell proliferation by an oxidative mechanism in the human [[HT1080|HT-1080]] [[fibrosarcoma]] cell line has recently been established.<ref>{{cite journal | last1 = Rajendra Prasad | first1 = N. | last2 = Karthikeyan | first2 = A. | last3 = Karthikeyan | first3 = S. | last4 = Reddy | first4 = B. V. | date = Mar 2011 | title = Inhibitory effect of caffeic acid on cancer cell proliferation by oxidative mechanism in human HT-1080 fibrosarcoma cell line | journal = Mol Cell Biochem | volume = 349 | issue = 1–2| pages = 11–19 | doi = 10.1007/s11010-010-0655-7 | pmid = 21116690 | s2cid = 28014579 }}</ref>
Caffeic acid is an [[antioxidant]] ''in vitro'' and also ''[[in vivo]]''.<ref name="pmid11208940">{{cite journal |last1=Olthof |first1=M. R. |last2=Hollman |first2=P. C. |last3=Katan |first3=M. B. |title=Chlorogenic acid and caffeic acid are absorbed in humans |journal=J. Nutr. |volume=131 |issue=1 |pages=66–71 |date=January 2001 |pmid=11208940 |doi= 10.1093/jn/131.1.66|doi-access=free }}</ref> Caffeic acid also shows immunomodulatory and [[anti-inflammatory]] activity. Caffeic acid outperformed the other antioxidants, reducing [[aflatoxin]] production by more than 95 percent. The studies are the first to show that oxidative stress that would otherwise trigger or enhance ''[[Aspergillus flavus]]'' aflatoxin production can be stymied by caffeic acid. This opens the door to use as a natural [[fungicide]] by supplementing trees with antioxidants.<ref name="urlNuts’New Aflatoxin Fighter: Caffeic Acid?">{{cite web |url=https://agresearchmag.ars.usda.gov/2006/oct/nuts |title=Nuts' New Aflatoxin Fighter: Caffeic Acid? }}</ref>
Studies of the [[carcinogenicity]] of caffeic acid have mixed results. Some studies have shown that it inhibits [[carcinogenesis]], and other experiments show carcinogenic effects.<ref name= Hirose>{{cite journal|journal=Carcinogenesis|volume=19|pages=207–212|year=1998|title=Carcinogenicity of antioxidants BHA, caffeic acid, sesamol, 4-methoxyphenol and catechol at low doses, either alone or in combination, and modulation of their effects in a rat medium-term multi-organ carcinogenesis model|first1=M. |last1=Hirose |first2=Y. |last2=Takesada |first3=H. |last3=Tanaka |first4=S. |last4=Tamano |first5=T. |last5=Kato |first6=T. |last6=Shirai |doi=10.1093/carcin/19.1.207|pmid=9472713|issue=1|doi-access=free }}</ref> Oral administration of high doses of caffeic acid in rats has caused [[stomach]] [[papilloma]]s.<ref name= Hirose/> In the same study, high doses of combined antioxidants, including caffeic acid, showed a significant decrease in growth of [[Colon (anatomy)|colon]] [[tumor]]s in those same rats. No significant effect was noted otherwise. Caffeic acid is listed under some Hazard Data sheets as a potential carcinogen,<ref name="urlCaffeic Acid (IARC Summary & Evaluation, Volume 56, 1993)">{{cite web |url=http://www.inchem.org/documents/iarc/vol56/03-caff.html |title=Caffeic Acid |work=IARC Summary & Evaluation |volume= 56 |date=1993 }}</ref> as has been listed by the [[International Agency for Research on Cancer]] as a [[List of IARC Group 2B carcinogens|Group 2B carcinogen]] ("possibly carcinogenic to humans").<ref>{{cite web|url=http://monographs.iarc.fr/ENG/Classification/ClassificationsGroupOrder.pdf|title=Agents Classified by the IARC Monographs|publisher=[[International Agency for Research on Cancer]]|website=iarc.fr|access-date=4 April 2018|archive-url=https://web.archive.org/web/20111025122327/http://monographs.iarc.fr/ENG/Classification/ClassificationsGroupOrder.pdf|archive-date=25 October 2011|url-status=dead}}</ref> More recent data show that [[bacteria]] in the rats' guts may alter the formation of [[metabolite]]s of caffeic acid.<ref>{{cite journal|journal=Proceedings of the National Academy of Sciences|volume=69|pages=1413–1415|year=1972|title=Caffeic acid metabolism by gnotobiotic rats and their intestinal bacteria|first1=M. A. |last1=Peppercorn |first2=P. |last2=Goldman |pmid=4504351|doi=10.1073/pnas.69.6.1413|issue=6|pmc=426714|bibcode=1972PNAS...69.1413P|doi-access=free}}</ref><ref>{{cite journal|journal=Journal of Nutrition|volume=133|pages=1853–1859|date=1 June 2003|title=Chlorogenic acid bioavailability largely depends on its metabolism by the gut microflora in rats|first1=M.-P. |last1=Gonthier |first2=M.-A. |last2=Verny |first3=C. |last3=Besson |first4=C. |last4=Rémésy |first5=A. |last5=Scalbert |pmid=12771329|issue=6|doi=10.1093/jn/133.6.1853|doi-access=free }}</ref> Other than caffeic acid being a [[thiamine]] antagonist (antithiamine factor), there have been no known ill effects of caffeic acid in humans.
Also, caffeic acid treatment attenuated lipopolysaccharide (LPS)-induced sickness behaviour in experimental animals by decreasing both peripheral and central [[cytokine]] levels along with oxidative stress inflicted by LPS.<ref>{{cite journal|last1=Basu|first1=Mallik S|display-authors=et al|title=Caffeic acid attenuates lipopolysaccharide-induced sickness behaviour and neuroinflammation in mice.|journal=Neuroscience Letters|volume=632|pages=218–223|date=3 Sep 2016|doi=10.1016/j.neulet.2016.08.044|pmid=27597761|s2cid=5361129}}</ref>
==
Caffeic acid may be the active ingredient in [[caffenol]], a do-it-yourself black-and-white [[photographic developer]] made from [[instant coffee]].<ref>{{cite web|website=Caffenol blog|url=https://caffenol.blogspot.com/2010/03/caffenol-c-m-recipe.html|title=Caffenol-C-M, recipe|date=2 March 2010}}</ref> The developing chemistry is similar to that of [[catechol]] or [[pyrogallol]].<ref>{{cite web|last=Williams|first=Scott|url=http://people.rit.edu/andpph/text-coffee.html|title=A Use for that Last Cup of Coffee: Film and Paper Development |work=Technical Photographic Chemistry 1995 Class|publisher=Imaging and Photographic Technology Department, School of Photographic Arts and Sciences, Rochester Institute of Technology}}</ref>
It is also used as a matrix in [[Matrix-assisted laser desorption/ionization|MALDI]] [[mass spectrometry]] analyses.<ref name="pmid2520223">{{cite journal |last1= Beavis |first1=R. C. |last2=Chait |first2=B. T. |title=Cinnamic acid derivatives as matrices for ultraviolet laser desorption mass spectrometry of proteins |journal=Rapid Commun. Mass Spectrom. |volume=3 |issue=12 |pages=432–435 |date=Dec 1989 |pmid=2520223 |doi=10.1002/rcm.1290031207 |bibcode=1989RCMS....3..432B }}</ref>
== Isomers ==
Isomers with the same molecular formula and in the hydroxycinammic acids family are:
* [[Umbellic acid]] (2,4-dihydroxycinnamic acid)
* [[2,3-Dihydroxycinnamic acid]]
* [[2,5-Dihydroxycinnamic acid]]
== References ==
{{Reflist|30em}}
== External links ==
* {{cite web|title=Chemical Land|work=Caffeic Acid as Carbocyclic Carboxylic Acid|url=http://www.chemicalland21.com/fc/CARBOCYCLIC%20CARBOXYLIC%20ACIDS.htm}}
{{Coffee}}
{{Hydroxycinnamic acid}}
{{Leukotrienergics}}
{{Purinergics}}
{{DEFAULTSORT:Caffeic Acid}}
[[Category:IARC Group 2B carcinogens]]
[[Category:Hydroxycinnamic acids]]
[[Category:Xanthine oxidase inhibitors]]
[[Category:Catechols]]
[[Category:Vinylogous carboxylic acids]]
| |||