Chemistry:Cyclopropane fatty acid
Cyclopropane fatty acids (CPA) are a subgroup of fatty acids that contain a cyclopropane group.[1]
Occurrence
Although cyclopropane fatty acids are usually rare, the seed oil from lychee contains nearly 40% CPAs in the form of their triglycerides.[2]
Olibanic acids are cyclopropane-containing undecylic acids that are implicated for their distinctive odor of frankincense.[3]
Biosynthesis
CPAs are derived from unsaturated fatty acids by cyclopropanation. The methylene donor is a methyl group on S-adenosylmethionine (SAM). The conversion is catalyzed by cyclopropane-fatty-acyl-phospholipid synthase.[4] The mechanism is proposed to involve transfer of a CH3+ group from SAM to the alkene, followed by deprotonation of the newly attached methyl group and ring closure.[5]
Cyclopropene fatty acids
Cyclopropene fatty acids are even rarer molecules. The best-known examples of fatty acids containing cyclopropene rings are malvalic acid and sterculic acid. A triglyceride made of 3 sterculic acid molecules esterified with glycerol is present in Sterculia foetida seed oil (in amounts greater than 60%) and at low levels in the seed oil of other species of Malvaceae[lower-alpha 1] (~12%), cottonseed oil (~1%). The cyclopropene ring is destroyed during refining and hydrogenation of the oils. They have attracted interest because they reduce levels of the enzyme stearoyl-CoA 9-desaturase (SCD), which catalyzes the biodesaturation of stearic acid to oleic acid.[8]
Notes
- ↑ A number of species in several genera of the Malvaceae family are known as 'Kapok trees'. For example: Ceiba pentandra, Bombax ceiba and B. costatum are all widely and ambiguously called "the kapok tree".[6][7]
References
- ↑ "Natural alicyclic fatty acids, cyclopropane, cyclopropene, cyclopentene - structure, composition, analysis, biosynthesis". Archived from the original on 2014-12-17. https://web.archive.org/web/20141217172219/http://lipidlibrary.aocs.org/Lipids/fa_cycl/index.htm. Retrieved 2015-02-02.
- ↑ Gaydou, E. M.; Ralaimanarivo, A.; Bianchini, J. P. "Cyclopropanoic Fatty-Acids of Litchi (Litchi-Chinensis) Seed Oil - a Reinvestigation" J. Agr. Food Chem. 1993, vol. 41, pp. 886-890. doi:10.1021/jf00030a009
- ↑ "What’s Hot, What’s Not: The Trends of the Past 20 Years in the Chemistry of Odorants". Angewandte Chemie International Edition 59 (38): 16310–16344. 14 September 2020. doi:10.1002/anie.202005719. https://onlinelibrary.wiley.com/doi/10.1002/anie.202005719.
- ↑ Grogan DW, Cronan JE Jr: Cyclopropane ring formation in membrane lipids of bacteria" Microbiol Mol Biol Rev 1997, vol. 61, pp. 429–441. doi:10.1128/mmbr.61.4.429-441.1997
- ↑ Ludger A. Wessjohann and Wolfgang Brandt, Thies Thiemann "Biosynthesis and Metabolism of Cyclopropane Rings in Natural Compounds" Chem. Rev., 2003, volume 103, pp 1625–1648. doi:10.1021/cr0100188
- ↑ Bohannon, M. B.; Kleiman, R. (April 1978). "Cyclopropene fatty acids of selected seed oils from bombacaceae, malvaceae, and sterculiaceae". Lipids 13 (4): 270–273. doi:10.1007/BF02533669. PMID 661511.
- ↑ Yu, Xiao-Hong; Rawat, Richa; Shanklin, John (December 2011). "Characterization and analysis of the cotton cyclopropane fatty acid synthase family and their contribution to cyclopropane fatty acid synthesis". BMC Plant Biology 11 (1): 97. doi:10.1186/1471-2229-11-97. PMID 21612656.
- ↑ Abraham, Samuel (1975). International encyclopedia of pharmacology and therapeutics: Pharmacology of lipid transport and atherosclerotic processes, Volume 1. Pergamon Press. p. 108. ISBN 9780080177625. https://books.google.com/books?id=QP1NAQAAIAAJ&q=%22cyclopropene+fatty+acids+were+specific+inhibitors%22.
Further reading
- Bao, X.; Katz, S.; Pollard, M.; Ohlrogge, J. (2002). "Carbocyclic fatty acids in plants: Biochemical and molecular genetic characterization of cyclopropane fatty acid synthesis of Sterculia foetida". Proceedings of the National Academy of Sciences 99 (10): 7172–7177. doi:10.1073/pnas.092152999. PMID 11997456. PMC 124547. Bibcode: 2002PNAS...99.7172B. http://www.pnas.org/cgi/reprint/99/10/7172.pdf.
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