Vernolic acid
 | |
| Names | |
|---|---|
| IUPAC name
(+)-(12S,13R)-Epoxy-cis-9-octadecenoic acid | |
| Other names
Linoleic acid 12:13-oxide | |
| Identifiers | |
503-07-1  | |
| ChemSpider | 4444572 (−)-isomer  4952464 (+)-isomer |
| Jmol interactive 3D | (+)-isomer: Image Image |
| PubChem | 5281128 (−)-isomer 6449780 (+)-isomer |
| |
| |
| Properties | |
| C18H32O3 | |
| Molar mass | 296.45 g·mol−1 |
| Appearance | Colorless oil |
| Melting point | 23 to 25 °C (73 to 77 °F; 296 to 298 K) |
| Insoluble | |
| Solubility in other solvents | organic solvents |
| Hazards | |
| Main hazards | flammable |
| Related compounds | |
| 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 | |
Vernolic acid is an organic compound and a fatty acid. This monounsaturated long chain carboxylic acid contains an epoxide and consists of two optical isomers. The (+) optical isomer's IUPAC designation is (+)-(12S,13R)-epoxy-cis-9-octadecenoic acid; it is also termed 12S,13R-EpOME, cis-12-epoxyoctadeca-cis-9-enoic acid, and (9Z)-(12S,13R)-12,13-epoxyoctadecenoic acid.[1] The (-) isomer's IUPAC designation is (-)-(12R,13S)-epoxy-cis-9-octadecenoic acid; it is also termed 12R,13S-EpOME, cis-12-epoxyoctadeca-cis-9-enoic acid, and (9Z)-(12R,13S)-12,13-epoxyoctadecenoic acid.[2] It is an isomer of coronaric acid, which is itself the (+) and (-), i.e. R,S and S,R optical isomers of 9,10-epoxy-12Z-octadecenoic acid (also termed 9(10)-EpOME and (+/-)-9(10)-epoxy-12Z-octadecenoic acid).[3] Vernolic acid was first definitively characterized in 1954.[4] It is the key component in vernonia oil, which is produced in abundance by the genera Vernonia and Euphorbia and is a potentially useful biofeedstock.
Toxicity
In a variety of mammalian species, vernolic acid is made by the metabolism of linoleic acid by certain cytochrome P450 epoxygenase enzymes; under these circumstances it is termed leukotoxin because of its toxic effects on leukocytes and other cell types and of its ability to produce multiple organ failure and respiratory distress when injected into rodent animal models of the acute respiratory distress syndrome.[5][6] These effects appear due to the conversion of vernolic acid to its dihydroxy counterparts, 12S,13R- and 12R,13S-dihydroxy-cis-9-octadecenoic acids by soluble epoxide hydrolase.[7] Some studies suggest but have not yet proven that vernolic acid is responsible for or contributes to multiple organ failure, respiratory distress, and certain other cataclysmic diseases in humans (see epoxygenase subsection on linoleic acid).
Vernonia oil
Vernonia oil is extracted from the seeds of the Vernonia galamensis (or ironweed), a plant native to eastern Africa. The seeds contain about 40 to 42% oil of which 73 to 80% is vernolic acid. The best varieties of V. anthelmintica contain about 30% less vernolic acid. Products that can be made from vernonia oil include epoxies for manufacturing adhesives, varnishes and paints, and industrial coatings. Its low viscosity recommends its use as a nonvolatile solvent in oil-based paints since it will become incorporated in the dry paint rather than evaporating into the air.[8]
This use of vernonia oil offers potential environmental benefits, since its use could reduce emissions associated with man-made chemicals.
In its application as an epoxy oil,[9] vernonia oil competes with soybean or linseed oil, which supply most of the market for these applications. Its low viscosity makes it more desirable than fully epoxidized linseed or soybean oils. It is more comparable to partially epoxidized linseed or soybean oil.[10]
Other plant sources
Vernolic acid is not commonly found in plants in significant quantities, but some plants which do contain it are Vernonia, Stokesia, Crepis (from the daisy family), and Euphorbia lagascae and Bernardia pulchella from the Euphorbiaceae.[11]
References
- ↑ CID 6449780 from PubChem
- ↑ See ChEBI @ http://www.ebi.ac.uk/chebi/chebiOntology.do?chebiId=CHEBI:38300
- ↑ CID 6246154 from PubChem
- ↑ Gunstone F. D. (1954). "Fatty acids. Part II. The nature of the oxygenated acid present in Vernonia anthelmintica (Willd.) seed oil". Journal of the Chemical Society 1954: 1611–1616. doi:10.1039/JR9540001611.
- ↑ Linhartová, Irena; Bumba, Ladislav; Mašín, Jiří; Basler, Marek; Osička, Radim; Kamanová, Jana; Procházková, Kateřina; Adkins, Irena; Hejnová-Holubová, Jana; Sadílková, Lenka; Morová, Jana; Šebo, Peter (2010). "RTX proteins: A highly diverse family secreted by a common mechanism". FEMS Microbiology Reviews 34 (6): 1076. doi:10.1111/j.1574-6976.2010.00231.x. PMID 20528947.
- ↑ Spector, Arthur A.; Kim, Hee-Yong (2015). "Cytochrome P450 epoxygenase pathway of polyunsaturated fatty acid metabolism". Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 1851 (4): 356. doi:10.1016/j.bbalip.2014.07.020.
- ↑ Greene, J. F.; Newman, J. W.; Williamson, K. C.; Hammock, B. D. (2000). "Toxicity of epoxy fatty acids and related compounds to cells expressing human soluble epoxide hydrolase". Chemical research in toxicology 13 (4): 217–26. PMID 10775319.
- ↑ T.M. Teynor; et al. "Vernonia". Alternative Field Crops Manual. Retrieved 2006-09-10.
- ↑ A.I Mohamed, T. Mebrahtu, and T. Andebrhan (1999). J. Janick, ed. "Variability in oil and vernolic acid contents in the new Vernonia galamensis collection from East Africa". Perspectives on new crops and new uses: 272–274. Retrieved 2006-09-10.
- ↑ Muturi, Patrick; Wang, Danqing; Dirlikov, Stoil (1994). "Epoxidized vegetable oils as reactive diluents I. Comparison of vernonia, epoxidized soybean and epoxidized linseed oils". Progress in Organic Coatings 25: 85. doi:10.1016/0300-9440(94)00504-4.
- ↑ Edgar B. Cahoon, Kevin G. Ripp, Sarah E. Hall, and Brian McGonigle (February 2002). "Transgenic Production of Epoxy Fatty Acids by Expression of a Cytochrome P450 Enzyme from Euphorbia lagascae Seed". Plant Physiol. 128 (2): 615–624. doi:10.1104/pp.010768. PMC 148923. PMID 11842164.