Dihomo-gamma-linolenic acid
Encyclopedia
Dihomo-γ-linolenic acid (DGLA) is a 20-carbon ω−6 fatty acid
. In physiological literature, it is given the name 20:3 (ω−6). DGLA is a carboxylic acid
with a 20-carbon chain and three cis
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 of linoleic acid
(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.
metabolites of DGLA are:
All of these effects are anti-inflammatory. This is in marked contrast with the analogous metabolites of arachidonic acid
(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
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.
Omega-6 fatty acid
n−6 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−6 position, that is, the sixth bond, counting from the methyl end.The biological effects of the n−6 fatty acids are largely mediated by their conversion to n-6 eicosanoids...
. In physiological literature, it is given the name 20:3 (ω−6). DGLA is a carboxylic acid
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
with a 20-carbon chain and three cis
Cis
Cis may have the following meanings:* "Cis-" as a prefix of Latin origin, meaning "on the same side [as]" or "on this side [of]", with several derived usages:** In chemistry, cis- refers to cis-trans isomerism...
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
Gamma-Linolenic acid
γ-Linolenic acid is a fatty acid found primarily in vegetable oils...
(GLA; 18:3, ω−6). GLA, in turn, is a desaturation product of linoleic acid
Linoleic acid
Linoleic acid is an unsaturated n-6 fatty acid. It is a colorless liquid at room temperature. In physiological literature, it has a lipid number of 18:2...
(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 eicosanoidEicosanoid
In biochemistry, eicosanoids are signaling molecules made by oxidation of twenty-carbon essential fatty acids, ....
metabolites of DGLA are:
- Series-1 thromboxaneThromboxaneThromboxane 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....
s (thromboxanes with 1 double-bond), via the COX-1 and COX-2CyclooxygenaseCyclooxygenase is an enzyme that is responsible for formation of important biological mediators called prostanoids, including prostaglandins, prostacyclin and thromboxane. Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain...
pathways. - Series-1 prostanoidProstanoidProstanoid is the term used to describe a subclass of eicosanoids consisting of: the prostaglandins , the thromboxanes and the prostacyclins - Biosynthesis : Cyclooxygenase catalyzes the conversion of the free essential fatty acids to...
s, via the COX-1 and COX-2 pathways. - A 15-hydroxyl derivative that blocks the transformation of arachidonic acidArachidonic acidArachidonic acid is a polyunsaturated omega-6 fatty acid 20:4.It is the counterpart to the saturated arachidic acid found in peanut oil, Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6).It is the counterpart to the saturated arachidic acid found in peanut oil,...
to leukotrieneLeukotrieneLeukotrienes are fatty signaling molecules. They were first found in leukocytes . One of their roles is to trigger contractions in the smooth muscles lining the trachea; their overproduction is a major cause of inflammation in asthma and allergic rhinitis...
s.
All of these effects are anti-inflammatory. This is in marked contrast with the analogous metabolites of arachidonic acid
Arachidonic acid
Arachidonic acid is a polyunsaturated omega-6 fatty acid 20:4.It is the counterpart to the saturated arachidic acid found in peanut oil, Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6).It is the counterpart to the saturated arachidic acid found in peanut oil,...
(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
Antithrombotic
A antithrombotic is a drug which reduces thrombus formation.Different antithrombotics affect different processes:* Antiplatelet drugs limit the migration or aggregation of platelets.* Anticoagulants limit the ability of the blood to clot....
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.