Docosapentaenoic acid (DPA) designates any straight open chain polyunsaturated fatty acid (PUFA) which contains 22 carbons and 5 double bonds. DPA is primarily used to designate two isomers, all-cis-4,7,10,13,16-docosapentaenoic acid (i.e. 4Z,7Z,10Z,13Z,16Z-docosapentaenoic acid) and all-cis-7,10,13,16,19-docosapentaenoic acid (i.e. 7Z,10Z,13Z,16Z,19Z-docosapentaenoic acid). They are also commonly termed n-6 DPA and n-3 DPA, respectively; these designations describe the position of the double bond being 6 or 3 carbons closest to the (omega) carbon at the methyl end of the molecule and is based on the biologically important difference that n-6 and n-3 PUFA are separate PUFA classes, i.e. the omega-6 fatty acids and omega-3 fatty acids, respectively. Mammals, including humans, can not interconvert these two classes and therefore must obtain dietary essential PUFA fatty acids from both classes in order to maintain normal health (see essential fatty acids).[1][2]
Isomers
editThe two isomers osbond acid and clupanodonic acid have the same number of double bonds, but on different positions along the chain, so they are regioisomers.
all-cis-4,7,10,13,16-docosapentaenoic acid (osbond acid)
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n-6 DPA is an ω-6 fatty acid with the trivial name osbond acid. It is formed in two steps from eicosatetraenoic acid (5,8,11,14-20:4n-6 or arachidonic acid, AA). Arachidonic acid is elongated to docosatetraenoic acid (7,10,13,16-22:4n-6 or adrenic acid, AdA), which in turn is converted by Δ4-desaturase to osbond acid.[3]
all-cis-7,10,13,16,19-docosapentaenoic acid (clupanodonic acid)
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n-3 DPA is an n-3 fatty acid with the trivial name clupanodonic acid. It is an intermediate compound between eicosapentaenoic acid (EPA 5,8,11,14,17-20:5n-3 or timnodonic acid) and docosahexaenoic acid (DHA 4,7,10,13,16,19-22:6n-3 or cervonic acid) in the metabolic pathway of DHA in eucaryotes. Eicosapentaenoic acid is elongated to clupanodonic acid, which in turn is converted by Δ4-desaturase to docosahexaenoic acid 22:6n-3 (see Docosahexaenoic acid § Biosynthesis).
Mammalian cells, including human cells, metabolize DPAn-3 to an array of products that are members of the specialized proresolving mediators class of PUFA metabolites. These metabolites include four resolvins of T series and three of D series (RvT1, RvT2, RvT3, RvT4, RvD1n-3, RvD2n-3, and RvD5n-3 (do not confuse with D series resolvins derived from DHA); see Specialized proresolving mediators § n-3 DPA-derived resolvins and Resolvin), two protectins (PD1n-3 and PD2n-3; see Specialized proresolving mediators § n-3 DPA-derived protectins/neuroprotectins and Neuroprotectin), and three maresins (MaR1n-3, MaR2n-3, and MaR3n-3; see Specialized proresolving mediators § n-3 DPA-derived maresins and Maresin).
Nutrition
editDocosapentaenoic acid (DPA) is an n-3 fatty acid that is structurally similar to eicosapentaenoic acid (EPA) with the same number of double bonds, but two more carbon chain units.[4]
Dietary sources
These are the top five sources for DPA according to the USDA Agricultural Research Service:[5]
- Fish oil, menhaden 0.668 g in 1 tbsp. (13.6 g)
- Fish oil, salmon 0.407 g in 1 tbsp. (13.6 g)
- Salmon, red (sockeye), filets with skin, smoked (Alaska Native) 0.335 g in 1 filet (108 g)
- Fish, salmon, Atlantic, farmed, raw 0.334 g in 3 oz (85 g)
- Beef, variety meats and by-products, brain, cooked, simmered 0.326 g in 3 oz (85 g)
Seal meat and human breast milk are rich in DPA.[4]
Functions
editClupanodonic acid, an omega-3 fatty acid, along with its metabolite DHA and other long chain omega-3 fatty acids, is under study to determine properties of omega-3 fats in humans, such as in inflammation mechanisms.[6]
See also
editReferences
edit- ^ Edwards IJ, O'Flaherty JT (2008). "Omega-3 Fatty Acids and PPARgamma in Cancer". PPAR Research. 2008: 358052. doi:10.1155/2008/358052. PMC 2526161. PMID 18769551.
- ^ Spector AA, Kim HY (2015). "Discovery of essential fatty acids". Journal of Lipid Research. 56 (1): 11–21. doi:10.1194/jlr.R055095. PMC 4274059. PMID 25339684.
- ^ Djuricic I, Calder PC (July 2021). "Beneficial Outcomes of Omega-6 and Omega-3 Polyunsaturated Fatty Acids on Human Health: An Update for 2021". Nutrients. 13 (7). Figure 3. doi:10.3390/nu13072421. PMC 8308533. PMID 34371930.
- ^ a b Yazdi, PG (Nov 2013). "A review of the biologic and pharmacologic role of docosapentaenoic acid n-3". F1000Res. 2: 256. doi:10.12688/f1000research.2-256.v2. PMC 4162505. PMID 25232466.
- ^ "DPA Nutrient List." National Nutrient Database for Standard Reference Release 27.
- ^ Dalli, J; Chiang, N; Serhan, C. N. (2015). "Elucidation of novel 13-series resolvins that increase with atorvastatin and clear infections" (PDF). Nature Medicine. 21 (9): 1071–5. doi:10.1038/nm.3911. PMC 4560998. PMID 26236990.