Eicosadienoic acid

Eicosadienoic Acid (EDA): A Comprehensive Reference

1. Identity and Chemical Characterization

1.1 Names and Classification

Eicosadienoic acid (EDA) is a polyunsaturated omega-6 fatty acid with the molecular formula C₂₀H₃₆O₂, classified as a 20-carbon fatty acid with two double bonds, specifically at the 11th and 14th positions (denoted as 20:2(ω-6)). It is a rare, naturally occurring n-6 polyunsaturated fatty acid (PUFA) found mainly in animal tissues.

The compound is known by several synonyms and designations. The most prevalent isomer in biological systems is the omega-6 variant, (11Z,14Z)-eicosadienoic acid, also referred to as dihomo-linoleic acid or 20:2 n-6, featuring cis double bonds between carbons 11–12 and 14–15. Additional systematic and trivial names found in the chemical literature include 11,14-eicosadienoic acid, cis-11,14-eicosadienoic acid, eicosa-11Z,14Z-dienoic acid, and all-cis-11,14-eicosadienoic acid. Its LIPID MAPS identifier is LMFA01030130, with a recorded exact monoisotopic mass of 308.271531 Da, and it is classified under Fatty Acyls → Fatty Acids and Conjugates → Unsaturated fatty acids (FA0103).

1.2 Structural Features and Isomers

EDA is classified as an omega-6 PUFA, a category characterized by double bonds starting at the n-6 position, which differentiates it from omega-3 PUFAs and saturated fats. Natural forms predominantly feature cis (Z) configurations at double bonds; trans (E) configurations are rare and typically result from industrial processing. The positions of double bonds are numbered from the carboxyl carbon (delta notation, e.g., Δ11,14) in structural descriptions, while omega notation is preferred in nutritional and metabolic discussions.

At least five isomers of eicosadienoic acid are known, differing in double bond positions. The most prevalent isomer in biological systems is the omega-6 variant, (11Z,14Z)-eicosadienoic acid, also referred to as dihomo-linoleic acid or 20:2 n-6, featuring cis double bonds between carbons 11–12 and 14–15. Another notable isomer is the omega-9 form, (5Z,11Z)-eicosadienoic acid, commonly known as keteleeronic acid, with cis double bonds at positions 5–6 and 11–12. Rarer in the plant world are the isomers with bonds in the positions 6 and 9, or 7 and 11, known as dihomotaxoleic acid.

Trans configurational variants, such as (11E,14E)-eicosadienoic acid, occur infrequently in nature but have been studied for their metabolic handling, often showing distinct oxidation patterns compared to cis forms. In natural sources like seed oils, eicosadienoic acid isomers generally constitute less than 2% of total fatty acids, with all-cis configurations predominating.

Like other polyunsaturated fatty acids (PUFAs), EDA is hydrophobic and insoluble in water but soluble in organic solvents.

1.3 Natural Sources

The omega-6 isomer with bonds in positions 11 and 14, also known as dihomo-linoleic acid, can be detected in modest concentrations, generally not exceeding 2%, in the seed oils of hundreds of plants, particularly Cruciferae, Ranunculaceae, and Pinaceae, as well as in human breast milk. The omega-9 isomer with bonds in positions 5 and 11, also known as keteleeronic acid, can be detected in modest concentrations, generally not exceeding 2%, in the seed oils of Pinaceae and Cupressaceae.

Among specific botanical sources, the concentrations vary by species. EDA is found in species from the Brassicaceae family, such as black mustard (Brassica nigra), where levels range from 3–4% in some cultivars, though generally lower in others like brown mustard (Brassica juncea) at 0.3–1%. Similar minor amounts are present in the Ranunculaceae family, exemplified by Delphinium species seed oil containing about 1% eicosadienoic acid. This isomer has also been identified in certain plant sources such as Pinus koraiensis seeds.

In the animal kingdom, EDA (20:2 n-6 c,c) is found mostly in pork, fats and oils, nuts and seeds, and fast food products. In the body, it is mostly found in breast milk and the placenta.

1.4 Endogenous Biosynthesis and Plasma Levels

Humans lack the capacity for de novo synthesis of eicosadienoic acid, as they cannot produce linoleic acid from scratch and rely entirely on dietary intake of this essential precursor for downstream elongation in tissues like the liver and brain. It is produced by a delta-9 elongase enzyme from linoleic acid and is converted into dihomo-gamma-linolenic acid, sciadonic acid, arachidonic acid, and other polyunsaturated fatty acids.

Eicosadienoic acid, as an omega-6 fatty acid, exhibits plasma concentrations ranging from approximately 0.35–20 μM in healthy adults, with variations reported across studies (e.g., 0.418 ± 0.162 μM in one cohort). Levels of this fatty acid reflect levels of other polyunsaturated omega-6 fatty acids. Plasma levels are significantly lower than those present in erythrocytes, which indicates that the conversion of linoleic to eicosadienoic acid occurs at a higher rate than the conversion of eicosadienoic acid to DGLA.

2. Traditional and Historical Use

While research into isolated medicinal properties of eicosadienoic acid is relatively recent, fatty acids like EDA have long held a place in traditional nutrition and herbal remedies. Because EDA is not isolated or concentrated in traditional preparations but is instead a minor constituent of dietary fats and oils, its history is inseparable from the broader history of fat-rich foods and oilseed use across cultures.

Historically, its presence in the human diet has been recognized as part of the broader family of essential fatty acids, which are vital for maintaining cell membrane integrity and supporting metabolic functions. EDA was not recognized as a discrete chemical entity until the development of modern lipid analytical chemistry in the twentieth century; consequently, no traditional medical system named or specifically targeted eicosadienoic acid as an ingredient. Its presence was implicit in preparations derived from the plant families and animal tissues now known to contain it.

Historically, cultures that consumed diets rich in plant-based oils benefited from the anti-inflammatory and cardiovascular-supportive properties attributed to these fatty acids. Indigenous populations often used seeds and oils high in eicosadienoic acid as part of their daily sustenance, indirectly supporting immune function, skin health, and joint flexibility.

In herbal medicine, eicosadienoic acid is rarely employed in isolation; instead, it works synergistically within multi-ingredient formulations. Herbalists have combined oil-rich seeds such as evening primrose, borage, and black currant — each containing a spectrum of beneficial fatty acids — to promote health.

While much scientific attention has focused on other omega-6 fatty acids like linoleic acid and arachidonic acid, interest in EDA has grown due to its potential health benefits and biological roles.

3. Key Constituents and Active Compounds in EDA-Rich Materials

When EDA is discussed in the context of dietary supplements or natural preparations, it invariably appears alongside other polyunsaturated fatty acids in the broader omega-6 pathway. Understanding EDA's role requires an appreciation of its structural relatives:

• Linoleic acid (LA, 18:2 n-6): EDA is elongated from linoleic acid (LA), and can also be metabolized to dihomo-γ-linolenic acid (DGLA), arachidonic acid (AA), and sciadonic acid (Δ5,11,14-20:3; SCA).
• Dihomo-gamma-linolenic acid (DGLA, 20:3 n-6): Eicosadienoic acid is the elongation product of gamma-linolenic acid (GLA) and the direct precursor of dihomo-gamma-linolenic acid (DGLA).
• Arachidonic acid (AA, 20:4 n-6): EDA is a precursor for longer-chain omega-6 fatty acids, such as dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA).
• Sciadonic acid (SCA, Δ5,11,14-20:3): EDA was taken up rapidly by macrophages and metabolized to SCA, and the percentages of both fatty acids increased in cellular phospholipids in a dose-dependent manner.

4. Mechanisms of Action

4.1 Integration into Cell Membranes

EDA, particularly the 20:2 n-6 isomer (11Z,14Z-eicosadienoic acid), serves as a structural component of cell membranes, where its polyunsaturated nature contributes to membrane fluidity and permeability. As an omega-6 fatty acid, EDA integrates into phospholipid bilayers, influencing the physical properties that affect protein function, signal transduction, and cellular homeostasis. This role is essential for maintaining membrane integrity in various tissues, allowing adaptive responses to environmental changes.

4.2 Modulation of the Omega-6 PUFA Pathway

Another elongation product of linoleic acid is eicosadienoic acid (EDA, C20:2), which is rapidly metabolized to dihomo-gamma-linolenic acid (DGLA, C20:3n6) and AA (C20:4). EDA was taken up rapidly by macrophages and metabolized to SCA, and the percentages of both fatty acids increased in cellular phospholipids in a dose-dependent manner. The incorporation of EDA into macrophage lipids increased the proportions of LA, DGLA, and AA as well, and reduced the proportion of total monounsaturated fatty acids.

4.3 Modulation of Inflammatory Mediators

When lipopolysaccharide (LPS) was applied to macrophages, EDA decreased the production of nitric oxide (NO), and increased that of prostaglandin E₂ (PGE₂) and tumor necrotic factor-α. The modulation of NO and PGE₂ was due, in part, to the modified expression of inducible nitric oxide synthase and type II cyclooxygenase. The differential effects of EDA on pro-inflammatory mediators might be attributed to the negative feedback mechanism associated with prolonged inflammation. Furthermore, EDA was a weaker pro-inflammatory agent than LA, and not as anti-inflammatory as SCA.

4.4 Leukotriene B4 Receptor Antagonism

The more common eicosadienoic acid competitively inhibits inosine 5'-monophosphate dehydrogenase (Ki = 3.1 µM) and inhibits the binding of LTB4 to its receptor on neutrophils (Ki = 3.0 µM). Along with other mono and polyunsaturated fatty acids, eicosadienoic acid can inhibit the binding of leukotriene B4 to pig neutrophil membranes, which may account in part for its anti-inflammatory activities.

This mechanism was characterized in the context of a broader study on essential fatty acids and the LTB4 receptor. Generally, fatty acids with two or more unsaturated sites and chain lengths of 18–22 were potent inhibitors of [³H]LTB4 binding; both n-3 and n-6 fatty acids were inhibitory. These results indicate that essential fatty acids are LTB4 receptor antagonists, which may account in part for their reported anti-inflammatory activities.

4.5 Effects on Gene Expression and Lipid Signaling

In research, eicosadienoic acid has been utilized to understand the role of fatty acids in modulating membrane dynamics and in the production of signaling molecules that govern various cellular processes. Its involvement in the synthesis of lipid mediators and its potential impact on the regulation of gene expression are areas of particular interest.

5. Scientific Evidence by Area of Use

5.1 Inflammation and Immune Modulation

The most studied biological role of EDA is its modulation of immune and inflammatory responses, though the available evidence is entirely preclinical (cell-based and animal).

The landmark peer-reviewed study in this area was conducted by Huang, Huang, Li, and Chuang (2011), published in Molecular and Cellular Biochemistry. EDA is described as a rare, naturally occurring n-6 PUFA found mainly in animal tissues, elongated from linoleic acid and further metabolized to DGLA, AA, and SCA. Although its metabolism had been extensively studied, few reports existed on how EDA might affect inflammatory processes. The study aimed to determine the effect of EDA on n-6 PUFA composition and the inflammatory response of murine RAW264.7 macrophages to lipopolysaccharide.

This study demonstrated that EDA can modulate the metabolism of PUFA and alter the responsiveness of macrophages to inflammatory stimulation. The differential effects of EDA on pro-inflammatory mediators might be attributed to the negative feedback mechanism associated with prolonged inflammation. Furthermore, EDA was a weaker pro-inflammatory agent than LA, and not as anti-inflammatory as SCA. The study showed that EDA can modulate the metabolism of PUFA and alter the responsiveness of macrophages to inflammatory stimulation.

Evidence strength: All available data on EDA and inflammation are derived from in vitro murine macrophage cell models. No human clinical trials or animal feeding studies with inflammation as a primary endpoint have been published as of the time of writing. The evidence for anti-inflammatory activity is therefore preliminary and limited to preclinical models.

5.2 Membrane Fluidity and Neurochemistry

EDA is classified within the family of polyunsaturated fatty acids (PUFAs), which are crucial components in cellular lipid metabolism and membrane architecture. The double bonds in eicosadienoic acid influence its fluidity and integration into cell membranes, affecting the membrane's properties such as fluidity, flexibility, and the function of embedded proteins and signaling pathways.

By studying eicosadienoic acid, researchers aim to explain the broader physiological roles of unsaturated fatty acids in maintaining cellular homeostasis, their influence on metabolic pathways, and their overall impact on the biophysical properties of cell membranes. This research contributes to a deeper understanding of lipid biochemistry and the complex network of lipid-mediated cellular regulation.

Evidence strength: Mechanistic and biophysical data from cell culture models only. No human studies have specifically targeted EDA's membrane effects as a clinical intervention.

5.3 Role in Macrophage Immunology and Lipid Mediator Production

EDA has been cited in reviews of macrophage-mediated immune responses. Macrophages have diverse functions in the pathogenesis, resolution, and repair of inflammatory processes. Elegant studies have elucidated the metabolomic and transcriptomic profiles of activated macrophages. However, the versatility of macrophage responses in inflammation is likely due, at least in part, to their ability to rearrange their repertoire of bioactive lipids, including fatty acids and oxylipins. Reviews describe the fatty acids and oxylipins generated by macrophages and their role in type 1 and type 2 immune responses. EDA's role in this context as an endogenous metabolite that can shift the balance of proinflammatory mediators has been acknowledged in this scholarly literature.

Evidence strength: Preclinical. The significance of EDA specifically among many fatty acids discussed in macrophage biology is not yet established in human research.

5.4 Recombinant Protein / Antibody Production (Biotechnological Research)

A notable recent publication in the biotechnological domain examined EDA's effects on Chinese hamster ovary (CHO) cells, which are widely used in biopharmaceutical production. The study aimed to investigate the effect of fatty acids on antibody expression in CHO cells. Among different fatty acids, cis,cis-11,14-eicosadienoic acid (EDA, C20:2, Δ11,14-cis) was screened to exert the strongest effect to boost antibody yield in CHO-IgG cells tested. In batch and fed-batch culture processes, the antibody yield was promoted by 48% and 59% respectively with supplementation of 10 µM of EDA.

Evidence strength: A single preclinical cell-culture study (2026). This finding has no direct relevance to human dietary supplementation but may point toward EDA's effects on cellular protein synthesis and apoptosis pathways.

5.5 Metabolic Disease Biomarker

In patients with isovaleric acidemia (OMIM: 243500), a metabolic disorder characterized by deficient isovaleryl-CoA dehydrogenase activity, plasma eicosadienoic acid levels are elevated at 16.9 ± 4.8 μM compared to normal ranges, reflecting altered polyunsaturated fatty acid status despite treatment. The clinical significance of elevations is presumed due to its role in the inflammatory cascade, though EDA itself has not yet been studied epidemiologically for disease associations.

Evidence strength: EDA functions here as an observed biomarker in a rare inborn error of metabolism. No therapeutic interventional studies using EDA in metabolic disease have been reported.

5.6 Postsurgical Inflammatory Response

A significant increase in the area value of α-linoleic and eicosadienoic acids was positively correlated with elevated levels of C-reactive protein at postoperative day 2 (Spearman's ρ = 0.843, P < 0.001; Spearman's ρ = 0.785, P = 0.001). Lipid droplets generated after laparoscopic lymphadenectomy during gastric cancer surgery contained various types of fatty acids, and some of them were found to be associated with the inflammatory response.

Evidence strength: Observational/correlational finding in a surgical context. EDA's elevation appears to be a marker of inflammatory activity rather than evidence of a therapeutic effect.

6. Body Systems and Health Areas Associated with EDA

6.1 Immune System

Eicosadienoic acid modulates the metabolism of polyunsaturated fatty acids and alters the responsiveness of macrophages to inflammatory stimulations. Its principal immunological role studied to date involves the regulation of macrophage responses to bacterial endotoxin, specifically affecting nitric oxide and prostaglandin production.

6.2 Cardiovascular System

EDA's position in the omega-6 PUFA cascade — as a precursor to DGLA and AA — places it within metabolic pathways that are well-established in cardiovascular lipid research. The biological effects of omega-6 fatty acids are largely mediated by their conversion to n-6 eicosanoids that bind to various receptors present in every tissue of the body. The direct cardiovascular effects of EDA itself remain unstudied in clinical populations.

6.3 Reproductive Biology and Lactation

The omega-6 EDA isomer can be detected in modest concentrations in human breast milk. In the body, EDA is mostly found in breast milk and the placenta. The presence of EDA in human milk suggests a physiological role in early infant nutrition and development, though its specific function in infant metabolism compared to other omega-6 fatty acids has not been the subject of dedicated clinical research.

6.4 Neurological System

Humans rely entirely on dietary intake of linoleic acid, the essential precursor, for downstream elongation in tissues including the brain. EDA's role as an elongation intermediate positions it within pathways relevant to neural lipid composition, though no studies specifically examining EDA's effects on neurological outcomes in humans have been published.

6.5 Cellular Biology and Apoptosis

EDA has been shown to enhance antibody production in CHO cells by prolonging culture longevity and attenuating apoptosis. The underlying anti-apoptotic mechanism inferred from cell-culture work may be relevant to understanding EDA's broader role in mammalian cell biology, though this has not been characterized in human tissue contexts.

7. Dosage Forms and Dosages Reported in Research

EDA is not commercially available as a mainstream dietary supplement intended for human consumption; it appears in research settings primarily as an analytical-grade or research-grade compound. The following dosage information is drawn exclusively from published experimental literature:

• In CHO cell culture experiments, cis,cis-11,14-eicosadienoic acid was supplemented at 10 µM in both batch and fed-batch culture processes, producing antibody yield increases of 48% and 59% respectively. This is a cell-culture dosage with no direct human relevance.
• The Ki for EDA's inhibition of inosine 5'-monophosphate dehydrogenase was measured at 3.1 µM, and its Ki for inhibition of LTB4 binding to its receptor on neutrophils was measured at 3.0 µM. These are pharmacological parameters derived from receptor binding assays.
• Plasma concentrations in healthy adults range from approximately 0.35–20 μM, with one cohort reporting a mean of 0.418 ± 0.162 μM.
• In patients with isovaleric acidemia, plasma eicosadienoic acid levels were elevated to 16.9 ± 4.8 μM compared to normal ranges.

No human clinical trial has established an efficacious, safe, or recommended dietary dose of isolated EDA supplementation. No official daily intake values have been set by regulatory bodies such as the NIH Office of Dietary Supplements, EFSA, or WHO for eicosadienoic acid specifically.

8. Safety Considerations and Interactions

8.1 Status as a Dietary Component

Eicosadienoic acid is rare but naturally occurring, and it is found in the human body with a broad range of pharmacological actions. As a minor constituent of the ordinary diet — particularly in pork and certain seed oils — human exposure at dietary concentrations has occurred throughout history without recognized adverse effects at those levels.

8.2 Differential Pro- and Anti-Inflammatory Effects

A safety-relevant consideration for any deliberate supplementation with EDA is the complexity of its inflammatory profile. When LPS was applied to macrophages, EDA decreased the production of nitric oxide (NO), and increased that of prostaglandin E₂ (PGE₂) and tumor necrotic factor-α. The modulation of NO and PGE₂ was due, in part, to the modified expression of inducible nitric oxide synthase and type II cyclooxygenase. The differential action — simultaneously decreasing NO and increasing PGE₂ — means that EDA does not have a simple "anti-inflammatory" profile, and its effects may vary depending on the immune context.

8.3 Interaction with the Omega-6 Cascade

Because EDA serves as an intermediary in the omega-6 fatty acid elongation pathway, supplementation could theoretically shift the balance between downstream metabolites. EDA was taken up rapidly by macrophages and metabolized to SCA, and the percentages of both fatty acids increased in cellular phospholipids in a dose-dependent manner. The incorporation of EDA into macrophage lipids increased the proportions of LA, DGLA, and AA as well, and reduced the proportion of total monounsaturated fatty acids. This indicates that EDA supplementation has measurable effects on the broader cellular fatty acid composition, which could have downstream consequences for eicosanoid production including prostaglandins and thromboxanes.

8.4 Elevations in Disease States

Elevations in EDA may be seen with high intake of LA and omega-6 fatty acid-rich foods. The clinical significance of elevations is presumed due to its role in the inflammatory cascade, though EDA itself has not yet been studied epidemiologically for disease associations.

8.5 Regulatory and Research Status

EDA is not listed as an approved pharmacological agent or a regulated dietary supplement ingredient by major regulatory agencies as of the date of this writing. It is commercially available only as a research-grade reagent. As a rare, naturally occurring n-6 PUFA found mainly in animal tissues, it is described by chemical suppliers as being for research use only. No human toxicology studies, safety assessments, or tolerability trials for supplemental EDA have been published in the peer-reviewed literature.

9. Summary of Evidence Limitations

The body of evidence specific to eicosadienoic acid as an isolated compound is very limited. The only peer-reviewed clinical or biological data that address EDA's effects directly are: one primary murine macrophage cell-culture study (Huang et al., 2011); one CHO-cell biotechnology study (Pei et al., 2026); receptor binding assay data for LTB4 antagonism; observational data from isovaleric acidemia patients; and a postsurgical correlational observation. No randomized controlled trials, human intervention studies, systematic reviews, or meta-analyses addressing EDA supplementation in humans have been published. All mechanistic claims about EDA's biological activity remain at the preclinical level.

References

• Huang YS, Huang WC, Li CW, Chuang LT. Eicosadienoic acid differentially modulates production of pro-inflammatory modulators in murine macrophages. Mol Cell Biochem. 2011;358(1-2):85-94. PubMed PMID: 21688154
• Eicosadienoic acid — Wikipedia
• LIPID MAPS Structure Database — 11,14-eicosadienoic acid (LMFA01030130)
• PubChem — Eicosadienoic Acid, CID 6439848
• Macrophage-Mediated Immune Responses: From Fatty Acids to Oxylipins — PMC (MDPI Molecules, 2022)
• Huang et al. (2011), Molecular and Cellular Biochemistry — Springer Link (abstract)
• Incorporation of Eicosatrienoic Acid Exerts Mild Anti-inflammatory Properties in Murine RAW264.7 Cells — Inflammation, Springer (2014) [citing Huang et al.]
• Pei X, Liu X, Wang R, et al. Eicosadienoic acid enhances antibody production in CHO cells by prolonging culture longevity and attenuating apoptosis. AMB Express. 2026. DOI: 10.1186/s13568-026-02050-4
• Yagaloff KA, Franco L, Simko B, Burghardt B. Essential fatty acids are antagonists of the leukotriene B4 receptor. Prostaglandins Leukot Essent Fatty Acids. 1995;52(5):293-7. PubMed PMID: 7630916
• IARC Exposome-Explorer — Eicosadienoic acid (cis-20:2n-6)
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• PMC — Revising the structure of a new eicosanoid from human platelets to 8,9–11,12-diepoxy-13-hydroxyeicosadienoic acid (PMC6556573)