Dihomo-γ-linolenic acid (DGLA) is a 20-carbon ω−6 fatty acid. (also called, cis,cis,cis-8,11,14-Eicosatrienoic acid) In physiological literature, it is given the name 20:3 (ω−6). DGLA is a

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...

with a 20-carbon chain and three ''

cis Cis or cis- may refer to: Places * Cis, Trentino, in Italy * In Poland: ** Cis, Świętokrzyskie Voivodeship, south-central ** Cis, Warmian-Masurian Voivodeship, north Math, science and biology * cis (mathematics) (cis(''θ'')), a trigonome ...

'' double bonds; the first double bond is located at the sixth carbon from the omega end. DGLA is the elongation product of γ-linolenic acid (GLA; 18:3, ω−6). GLA, in turn, is a desaturation product (

Delta 6 desaturase In enzymology, a linoleoyl-CoA desaturase (also Delta 6 desaturase, ) is an enzyme that converts between types of fatty acids, which are essential nutrients in the human body. The enzyme mainly catalyzes the chemical reaction :linoleoyl-CoA + A ...

) of

linoleic acid Linoleic acid (LA) is an organic compound with the formula COOH(CH2)7CH=CHCH2CH=CH(CH2)4CH3. Both alkene groups are cis-trans isomerism, ''cis''. It is a fatty acid sometimes denoted 18:2 (n-6) or 18:2 ''cis''-9,12. A linoleate is a salt (chem ...

(18:2, ω−6). DGLA is made in the body by the elongation of GLA, by an efficient enzyme which does not appear to suffer any form of (dietary) inhibition. DGLA is an extremely uncommon fatty acid, found only in trace amounts in animal products.

Biological effects

The

eicosanoid Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, around 20 carbon units in length. Eicosanoids are a s ...

metabolites of DGLA are: * Series-1

thromboxane Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for its ...

s (thromboxanes with 1 double-bond), via the COX-1 and COX-2 pathways. * Series-1

prostanoid Prostanoids are active lipid mediators that regulate inflammatory response. Prostanoids are a subclass of eicosanoids consisting of the prostaglandins (mediators of inflammatory and anaphylactic reactions), the thromboxanes (mediators of vasocons ...

s, via the COX-1 and COX-2 pathways. * A 15-hydroxyl derivative that blocks the transformation of

arachidonic acid Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6), or 20:4(5,8,11,14). It is structurally related to the saturated arachidic acid found in cupuaçu butter. Its name derives from the New Latin word ''arachi ...

leukotriene Leukotrienes are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxygenase. Leukotrienes ...

s. All of these effects are anti-inflammatory. This is in marked contrast with the analogous metabolites of

(AA), which are the series-2 thromboxanes and prostanoids and the series-4 leukotrienes. In addition to yielding anti-inflammatory eicosanoids, DGLA competes with AA for COX and lipoxygenase, inhibiting the production of AA's eicosanoids. Taken orally in a small study, DGLA produced

antithrombotic An antithrombotic agent is a drug that reduces the formation of blood clots (thrombi).http://cancerweb.ncl.ac.uk/cgi-bin/omd?antithrombotic Antithrombotics can be used therapeutically for prevention (primary prevention, secondary prevention) or tr ...

effects. Supplementing dietary GLA increases serum DGLA, as well as serum AA levels. Cosupplementation with GLA and EPA lowers serum AA levels by blocking Δ-5-desaturase activity, while also lowering leukotriene synthesis in neutrophils.

References

{{DEFAULTSORT:Dihomo-gamma-linolenic acid Fatty acids Alkenoic acids

Biological effects

See also

References