{{Chembox <!-- Images --> | Name = Exocarpic acid | ImageFile = Exocarpic acid.svg | ImageSize = | ImageAlt = <!-- Names --> | IUPACName = (''E'')-octadec-13-en-9,11-diynoic acid | OtherNames = Octadeca-trans-13-ene-9,11-diynoic acid | Section1 = {{Chembox Identifiers | CASNo = 13089-73-1 | CASNo_Ref = {{Cascite|changed|CAS}} | ChemSpiderID = 4472109 | DTXSID = | EC_number = | ChEBI = 191240 | ChEMBL = 2204412 | UNII = | PubChem = 5312684 | InChI = InChI=1/C18H26O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h5-6H,2-4,11-17H2,1H3,(H,19,20)/b6-5+/f/h19H | InChIKey = ACHMRCSARDWYGC-AATRIKPKSA-N | SMILES = C(CCCCCCCC#CC#C\C=C\CCCC)(=O)O }} | Section2 = {{Chembox Properties | H=26|O=2|C=18 | MolarMass = | Appearance = | Density = | MeltingPtC = | BoilingPtC = | BoilingPt_ref = | Solubility = }} | Section3 = {{Chembox Hazards | GHSPictograms = | GHSSignalWord = | GHS_ref = | HPhrases = | PPhrases = | MainHazards = | FlashPt = | AutoignitionPt = }} }} thumb|200px|right|''Sarcophyte sanguinea'' contains free exocarpic acid '''Exocarpic acid''' is an unsaturated, conjugated fatty acid with one double bond and two triple bonds. It is isomeric to isanic acid and belongs to the class of alkyne and alkenoic acids, as well as the diynes and enynes. The acid's delta notation is 18:3-Δ-9a,11a,13t.<ref>{{cite book |last1=Chow |first1=Ching Kuang |title=Fatty Acids in Foods and Their Health Implications |date=12 November 1999 |publisher=CRC Press |isbn=978-1-4200-0153-2 |page=10 |url=https://books.google.com/books?id=zg12ZkXgGUkC&dq=Exocarpic+acid&pg=PA1023 |access-date=9 April 2025 |language=en}}</ref> Its structural formula is CH<sub>3</sub>(CH<sub>2</sub>)<sub>3</sub>−CH=CH−C≡CC≡C−(CH<sub>2</sub>)<sub>7</sub>−COOH.
The acid was initially isolated in 1959, by H. H. Hatt and co-workers, from the roots of the Australian tree ''Exocarpos cupressiformis''; from this genus they derived the common name of exocarpic acid.<ref>{{cite journal |last1=Hatt |first1=H. H. |title=Acetylenic acids from fats of Santalaceae and Olacaceae: Seed and root oils of Exocarpus cupressiformis Labill |journal=Australian Journal of Chemistry |date=1 January 1959 |volume=12 |issue=2 |pages=190–195 |doi=10.1071/CH9590190 |url=https://scispace.com/papers/acetylenic-acids-from-fats-of-santalaceae-and-olacaceae-seed-3l3jh6kybs |access-date=9 April 2025 |language=en |issn=0004-9425|url-access=subscription }}</ref>
==Natural occurrence== Exocarpic acid is found in various plant species of the order ''Santalales''.
In the family ''Olacaceae'', it occurs, among others, in the seed oils of ''Curupira tefeensis''<ref>{{cite journal |last1=Spitzer |first1=V. |last2=Marx |first2=F. |last3=Maia |first3=J. G. |last4=Pfeilsticker |first4=K. |title=Curupira tefeensis II: Occurrence of Acetylenic Fatty Acids |journal=Lipid / Fett |date=1991 |volume=93 |issue=5 |pages=169–174 |doi=10.1002/lipi.19910930502 |url=https://onlinelibrary.wiley.com/doi/10.1002/lipi.19910930502 |access-date=9 April 2025 |language=en |issn=1521-4133|url-access=subscription }}</ref> and ''Olax dissitiflora''.<ref>{{cite journal |last1=Mavundza |first1=E. J. |last2=Chukwujekwu |first2=J. C. |last3=Maharaj |first3=R. |last4=Finnie |first4=J. F. |last5=Van Heerden |first5=F. R. |last6=Van Staden |first6=J. |title=Identification of compounds in Olax dissitiflora with larvacidal effect against Anopheles arabiensis |journal=South African Journal of Botany |date=1 January 2016 |volume=102 |pages=1–3 |doi=10.1016/j.sajb.2015.06.013 |issn=0254-6299|doi-access=free |bibcode=2016SAJB..102....1M }}</ref> In the family ''Santalaceae'', it occurs in several species of the genus ''Thesium'', such as mountain flax and ''Thesium chinense'',<ref name="Liu">{{cite journal |last1=Liu |first1=Chang |last2=Li |first2=Xiao-Tian |last3=Cheng |first3=Rong-Rong |last4=Han |first4=Zhu-Zhen |last5=Yang |first5=Li |last6=Song |first6=Zhong-Chen |last7=Wang |first7=Zheng-Tao |title=Anti-oral common pathogenic bacterial active acetylenic acids from Thesium chinense Turcz |journal=Journal of Natural Medicines |date=1 March 2018 |volume=72 |issue=2 |pages=433–438 |doi=10.1007/s11418-018-1180-3 |pmid=29435792 |url=https://link.springer.com/article/10.1007/s11418-018-1180-3 |access-date=9 April 2025 |language=en |issn=1861-0293|url-access=subscription }}</ref> as well as in several species of the genus ''Buckleya'', such as ''Buckleya lanceolata''<ref>{{cite journal |last1=Hopkins |first1=C. Y. |last2=Chisholm |first2=Mary J. |last3=Cody |first3=W. J. |title=Fatty acid components of some Santalaceae seed oils |journal=Phytochemistry |date=1 January 1969 |volume=8 |issue=1 |pages=161–165 |doi=10.1016/S0031-9422(00)85808-2 |bibcode=1969PChem...8..161H |url=https://www.sciencedirect.com/science/article/abs/pii/S0031942200858082 |access-date=9 April 2025 |issn=0031-9422|url-access=subscription }}</ref> and ''Exocarpos sparteus''. It also occurs in small amounts in the isano oil from ''Ongokea gore''.
The parasitic plant ''Sarcophyte sanguinea'' from the family ''Balanophoraceae'' contains free (not present in the form of glycerides) exocarpic acid.<ref>{{cite journal |last1=Naidoo Siegfried E. Drewes |first1=Lovina A. C. |last2=Staden |first2=J. Van |last3=Hutchings |first3=Anne |title=Exocarpic acid and other compounds from tubers and inflorescences of Sarcophyte sanguinea |journal=Phytochemistry |date=1 January 1992 |volume=31 |issue=11 |pages=3929–3931 |doi=10.1016/S0031-9422(00)97556-3 |bibcode=1992PChem..31.3929N |url=https://www.sciencedirect.com/science/article/abs/pii/S0031942200975563 |access-date=9 April 2025 |issn=0031-9422|url-access=subscription }}</ref>
==Characteristics== Exocarpic acid exerts antibacterial activity against ''Mycobacterium tuberculosis'' by inhibiting the biosynthesis of mycolic acids.<ref>{{cite book |title=Hydroxy Acids—Advances in Research and Application: 2012 Edition |date=26 December 2012 |publisher=ScholarlyEditions |isbn=978-1-4816-0039-2 |url=https://books.google.com/books?id=JrVeX7xl8AYC&dq=Exocarpic+acid&pg=PT135 |access-date=9 April 2025 |language=en}}</ref><ref>{{cite journal |last1=Koch |first1=Michael |last2=Bugni |first2=Tim S. |last3=Sondossi |first3=Mohammad |last4=Ireland |first4=Chris M. |last5=Barrows |first5=Louis R. |title=Exocarpic Acid Inhibits Mycolic Acid Biosynthesis in Mycobacterium tuberculosis |journal=Planta Medica |date=October 2010 |volume=76 |issue=15 |pages=1678–1682 |doi=10.1055/s-0030-1249939 |pmid=20506078 |bibcode=2010PlMed..76.1678K |url=https://www.thieme-connect.de/products/ejournals/abstract/10.1055/s-0030-1249939 |access-date=9 April 2025 |language=en |issn=0032-0943|url-access=subscription }}</ref> The acid also exerts antibacterial activity against several bacteria that cause oral infections.<ref name="Liu"/>
== References == <references/>
{{Fatty acids}}
Category:Alkenoic acids Category:Fatty acids Category:Conjugated diynes