Phytanic acid
{{chembox
| verifiedrevid = 436078588
| ImageFile = Phytanic acid.png
| ImageSize = 250px
| IUPACName = (7R,11R)-3,7,11,15-Tetramethylhexadecanoic acid
| OtherNames = phytanoic acid
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 14721-66-5
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 8OYE5TF5VL
| PubChem = 468706
| SMILES = CC(C)CCC[C@@H](C)CCC[C@@H](C)CCCC(C)CC(=O)O
| MeSHName = Phytanic+acid
| ChemSpiderID = 411797
| StdInChI = 1S/C20H40O2/c1-16(2)9-6-10-17(3)11-7-12-18(4)13-8-14-19(5)15-20(21)22/h16-19H,6-15H2,1-5H3,(H,21,22)/t17-,18-,19?/m1/s1
| StdInChIKey = RLCKHJSFHOZMDR-PWCSWUJKSA-N
}}
|Section2={{Chembox Properties
| C=20 | H=40 | O=2
| Appearance =
| Density =
| MeltingPt =
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|Section3={{Chembox Hazards
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Phytanic acid (or 3,7,11,15-tetramethyl hexadecanoic acid) is a branched-chain fatty acid that humans can obtain through the consumption of dairy products, ruminant animal fats, and certain fish.{{cite journal | last1 = Brown | first1 = P. J. | display-authors = etal | year = 1993 | title = The determination of phytanic acid and phytol in certain foods and the application of this knowledge to the choice of suitable convenience foods for patients with Refsum's disease | doi = 10.1111/j.1365-277x.1993.tb00375.x | journal = Journal of Human Nutrition and Dietetics | volume = 6 | pages = 295–305 }} Western diets are estimated to provide 50–100 mg of phytanic acid per day.Steinberg, D. Phytanic acid storage disease (Refsum's disease). In: Metabolic Basis of Inherited Disease. Edited by Stanbury JB, Wyngarden JB, Fredericksen DS, Goldstein JL, Brown MS, 5th edn. New York: McGraw Hill; 1983: 731-747. In a study conducted in Oxford, individuals who consumed meat had, on average, a 6.7-fold higher geometric mean plasma phytanic acid concentration than did vegans.{{Cite journal
| last1 = Allen | first1 = N. E.
| last2 = Grace | first2 = P. B.
| last3 = Ginn | first3 = A.
| last4 = Travis | first4 = R. C.
| last5 = Roddam | first5 = A. W.
| last6 = Appleby | first6 = P. N.
| last7 = Key | first7 = T.
| doi = 10.1017/S000711450782407X
| title = Phytanic acid: Measurement of plasma concentrations by gas–liquid chromatography–mass spectrometry analysis and associations with diet and other plasma fatty acids
| journal = British Journal of Nutrition
| volume = 99
| issue = 3
| pages = 653–659
| year = 2007
| pmid = 17868488
| doi-access = free
}}
Human pathology
Unlike most fatty acids, phytanic acid cannot be metabolized by β-oxidation. Instead, it undergoes α-oxidation in the peroxisome, where it is converted into pristanic acid by the removal of one carbon.{{Cite journal
| last1 = Brink | first1 = D. M.
| last2 = Wanders | first2 = R. J. A.
| doi = 10.1007/s00018-005-5463-y
| title = Phytanic acid: Production from phytol, its breakdown and role in human disease
| journal = Cellular and Molecular Life Sciences
| volume = 63
| issue = 15
| pages = 1752–1765
| year = 2006
| pmid = 16799769
| pmc = 11136310
}} Pristanic acid can undergo several rounds of β-oxidation in the peroxisome to form medium chain fatty acids that can be converted to carbon dioxide and water in mitochondria.
Individuals with adult Refsum disease, an autosomal recessive neurological disorder caused by mutations in the PHYH gene, have impaired α-oxidation activity and accumulate large stores of phytanic acid in their blood and tissues.{{Cite journal
| last1 = Quintaliani | first1 = G.
| last2 = Buoncristiani | first2 = U.
| last3 = Orecchini | first3 = A.
| last4 = Pierini | first4 = P.
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| title = The Umbria Regional Registry for hemodialyzed and transplanted patients. Preliminary experience with an informatic procedure
| journal = Contributions to Nephrology
| volume = 109
| pages = 96–99
| year = 1994
| doi = 10.1159/000423294
| pmid = 7956237
}} This frequently leads to peripheral polyneuropathy, cerebellar ataxia, retinitis pigmentosa, anosmia, and hearing loss.{{Cite journal
| last1 = Komen | first1 = J. C.
| last2 = Komen | first2 = R. J. A.
| title = Peroxisomes, Refsum's disease and the α- and ω-oxidation of phytanic acid
| journal = Biochemical Society Transactions
| volume = 35
| issue = Pt 5
| pages = 865–869
| year = 2007
| pmid = 17956234
| doi = 10.1042/BST0350865
}}
Presence in other organisms
In ruminant animals, the gut fermentation of ingested plant materials liberates phytol, a constituent of chlorophyll, which is then converted to phytanic acid and stored in fats.{{Cite journal
| doi = 10.1023/A:1005476631419
| last1 = Verhoeven | first1 = N. M.
| last2 = Wanders | first2 = R. J.
| last3 = Poll-The | first3 = B. T.
| last4 = Saudubray | first4 = J. M.
| last5 = Jakobs | first5 = C.
| title = The metabolism of phytanic acid and pristanic acid in man: a review
| journal = Journal of Inherited Metabolic Disease
| volume = 21
| issue = 7
| pages = 697–728
| year = 1998
| pmid = 9819701
}} In contrast to observations made in humans, there is indirect evidence that diverse non-human primates, including the great apes other than humans (bonobos, chimpanzees, gorillas and orangutans), can derive significant amounts of phytanic acid from the hindgut fermentation of plant materials.{{Cite journal
| last1 = Watkins | first1 = P. A.
| last2 = Moser | first2 = A. B.
| last3 = Toomer | first3 = C. B.
| last4 = Steinberg | first4 = S. J.
| last5 = Moser | first5 = H. W.
| last6 = Karaman | first6 = M. W.
| last7 = Ramaswamy | first7 = K.
| last8 = Siegmund | first8 = K. D.
| last9 = Lee | first9 = D. R.
| last10 = Ely | first10 = J. J.
| last11 = Ryder | first11 = O. A.
| last12 = Hacia | first12 = J. G.
| title = Identification of differences in human and great ape phytanic acid metabolism that could influence gene expression profiles and physiological functions
| journal = BMC Physiology
| volume = 10
| pages = 19
| year = 2010
| pmid = 20932325
| pmc = 2964658
| doi = 10.1186/1472-6793-10-19
| doi-access = free
| last1 = Moser | first1 = A. B.
| last2 = Hey | first2 = J.
| last3 = Dranchak | first3 = P. K.
| last4 = Karaman | first4 = M. W.
| last5 = Zhao | first5 = J.
| last6 = Cox | first6 = L. A.
| last7 = Ryder | first7 = O. A.
| last8 = Hacia | first8 = J. G.
| doi = 10.1186/1476-511X-12-10
| title = Diverse captive non-human primates with phytanic acid-deficient diets rich in plant products have substantial phytanic acid levels in their red blood cells
| journal = Lipids in Health and Disease
| volume = 12
| issue = 1
| pages = 10
| year = 2013
| pmid = 23379307
| pmc = 3571895
| doi-access = free
}}
Freshwater sponges contain terpenoid acids such as 4,8,12-trimethyltridecanoic, phytanic and pristanic acids, which indicates that these acids may have chemotaxonomical significance for both marine and freshwater sponges.{{cite journal | last1 = Rezanka | first1 = T. | last2 = Dembitsky | first2 = V. M. | year = 1993 | title = Isoprenoid polyunsaturated fatty acids from freshwater sponges | journal = Journal of Natural Products | volume = 56 | issue = 11 | pages = 1898–1904 | doi=10.1021/np50101a005}}
Insects, such as the sumac flea beetle, are reported to use phytol and its metabolites (e.g. phytanic acid) as chemical deterrents against predation.{{cite journal | last1 = Venci | first1 = F.V. | last2 = Morton | first2 = T.C. | year = 1998 | title = The shield defense of the sumac flea beetle, Blepharida rhois (Chrysomelidae: Alticinae) | journal = Chemoecology | volume = 8 | pages = 25–32 | doi = 10.1007/PL00001800 }} These compounds originate from host plants.
Modulator of transcription
Phytanic acid and its metabolites have been reported to bind to and/or activate the transcription factors PPAR-alpha{{Cite journal
| last1 = Gloerich | first1 = J.
| last2 = Van Vlies | first2 = N.
| last3 = Jansen | first3 = G. A.
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| last5 = Ruiter | first5 = J. P. N.
| last6 = Van Werkhoven | first6 = M. A.
| last7 = Duran | first7 = M.
| last8 = Vaz | first8 = F. M.
| last9 = Wanders | first9 = R. J. A.
| title = A phytol-enriched diet induces changes in fatty acid metabolism in mice both via PPAR -dependent and -independent pathways
| journal = The Journal of Lipid Research
| volume = 46
| issue = 4
| pages = 716–26
| year = 2005
| doi = 10.1194/jlr.M400337-JLR200 | pmid=15654129
| doi-access = free
}} and retinoid X receptor (RXR).{{Cite journal
| doi = 10.1091/mbc.7.8.1153
| last1 = Kitareewan | first1 = S.
| last2 = Burka | first2 = L. T.
| last3 = Tomer | first3 = K. B.
| last4 = Parker | first4 = C. E.
| last5 = Deterding | first5 = L. J.
| last6 = Stevens | first6 = R. D.
| last7 = Forman | first7 = B. M.
| last8 = Mais | first8 = D. E.
| last9 = Heyman | first9 = R. A.
| last10 = McMorris | first10 = T.
| last11 = Weinberger | first11 = C.
| title = Phytol metabolites are circulating dietary factors that activate the nuclear receptor RXR
| journal = Molecular Biology of the Cell
| volume = 7
| issue = 8
| pages = 1153–1166
| year = 1996
| pmid = 8856661
| pmc = 275969
}}