Reaction Process: WikiPathways:WP4586
Metabolism of alpha-linolenic acid related metabolites
find 14 related metabolites which is associated with chemical reaction(pathway) Metabolism of alpha-linolenic acid
12-HPEPE ⟶ 12-HEPE
linolenate(18:3)
alpha-Linolenic acid (ALA) is a polyunsaturated fatty acid (PUFA). It is a member of the group of essential fatty acids called omega-3 fatty acids. alpha-Linolenic acid, in particular, is not synthesized by mammals and therefore is an essential dietary requirement for all mammals. Certain nuts (English walnuts) and vegetable oils (canola, soybean, flaxseed/linseed, olive) are particularly rich in alpha-linolenic acid. Omega-3 fatty acids get their name based on the location of one of their first double bond. In all omega-3 fatty acids, the first double bond is located between the third and fourth carbon atom counting from the methyl end of the fatty acid (n-3). Although humans and other mammals can synthesize saturated and some monounsaturated fatty acids from carbon groups in carbohydrates and proteins, they lack the enzymes necessary to insert a cis double bond at the n-6 or the n-3 position of a fatty acid. Omega-3 fatty acids like alpha-linolenic acid are important structural components of cell membranes. When incorporated into phospholipids, they affect cell membrane properties such as fluidity, flexibility, permeability, and the activity of membrane-bound enzymes. Omega-3 fatty acids can modulate the expression of a number of genes, including those involved with fatty acid metabolism and inflammation. alpha-Linolenic acid and other omega-3 fatty acids may regulate gene expression by interacting with specific transcription factors, including peroxisome proliferator-activated receptors (PPARs) and liver X receptors (LXRs). alpha-Linolenic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism. α-Linolenic acid can be obtained by humans only through their diets. Humans lack the desaturase enzymes required for processing stearic acid into A-linoleic acid or other unsaturated fatty acids. Dietary α-linolenic acid is metabolized to stearidonic acid, a precursor to a collection of polyunsaturated 20-, 22-, 24-, etc fatty acids (eicosatetraenoic acid, eicosapentaenoic acid, docosapentaenoic acid, tetracosapentaenoic acid, 6,9,12,15,18,21-tetracosahexaenoic acid, docosahexaenoic acid).[12] Because the efficacy of n−3 long-chain polyunsaturated fatty acid (LC-PUFA) synthesis decreases down the cascade of α-linolenic acid conversion, DHA synthesis from α-linolenic acid is even more restricted than that of EPA.[13] Conversion of ALA to DHA is higher in women than in men.[14] α-Linolenic acid, also known as alpha-linolenic acid (ALA) (from Greek alpha meaning "first" and linon meaning flax), is an n−3, or omega-3, essential fatty acid. ALA is found in many seeds and oils, including flaxseed, walnuts, chia, hemp, and many common vegetable oils. In terms of its structure, it is named all-cis-9,12,15-octadecatrienoic acid.[2] In physiological literature, it is listed by its lipid number, 18:3 (n−3). It is a carboxylic acid with an 18-carbon chain and three cis double bonds. The first double bond is located at the third carbon from the methyl end of the fatty acid chain, known as the n end. Thus, α-linolenic acid is a polyunsaturated n−3 (omega-3) fatty acid. It is a regioisomer of gamma-linolenic acid (GLA), an 18:3 (n−6) fatty acid (i.e., a polyunsaturated omega-6 fatty acid with three double bonds). Alpha-linolenic acid is a linolenic acid with cis-double bonds at positions 9, 12 and 15. Shown to have an antithrombotic effect. It has a role as a micronutrient, a nutraceutical and a mouse metabolite. It is an omega-3 fatty acid and a linolenic acid. It is a conjugate acid of an alpha-linolenate and a (9Z,12Z,15Z)-octadeca-9,12,15-trienoate. Alpha-linolenic acid (ALA) is a polyunsaturated omega-3 fatty acid. It is a component of many common vegetable oils and is important to human nutrition. alpha-Linolenic acid is a metabolite found in or produced by Escherichia coli (strain K12, MG1655). Linolenic Acid is a natural product found in Prunus mume, Dipteryx lacunifera, and other organisms with data available. Linolenic Acid is an essential fatty acid belonging to the omega-3 fatty acids group. It is highly concentrated in certain plant oils and has been reported to inhibit the synthesis of prostaglandin resulting in reduced inflammation and prevention of certain chronic diseases. Alpha-linolenic acid (ALA) is a polyunsaturated omega-3 fatty acid. It is a component of many common vegetable oils and is important to human nutrition. A fatty acid that is found in plants and involved in the formation of prostaglandins. Seed oils are the richest sources of α-linolenic acid, notably those of hempseed, chia, perilla, flaxseed (linseed oil), rapeseed (canola), and soybeans. α-Linolenic acid is also obtained from the thylakoid membranes in the leaves of Pisum sativum (pea leaves).[3] Plant chloroplasts consisting of more than 95 percent of photosynthetic thylakoid membranes are highly fluid due to the large abundance of ALA, evident as sharp resonances in high-resolution carbon-13 NMR spectra.[4] Some studies state that ALA remains stable during processing and cooking.[5] However, other studies state that ALA might not be suitable for baking as it will polymerize with itself, a feature exploited in paint with transition metal catalysts. Some ALA may also oxidize at baking temperatures. Gamma-linolenic acid (γ-Linolenic acid) is an omega-6 (n-6), 18 carbon (18C-) polyunsaturated fatty acid (PUFA) extracted from Perilla frutescens. Gamma-linolenic acid supplements could restore needed PUFAs and mitigate the disease[1]. Gamma-linolenic acid (γ-Linolenic acid) is an omega-6 (n-6), 18 carbon (18C-) polyunsaturated fatty acid (PUFA) extracted from Perilla frutescens. Gamma-linolenic acid supplements could restore needed PUFAs and mitigate the disease[1]. α-Linolenic acid, isolated from Perilla frutescens, is an essential fatty acid that cannot be synthesized by humans. α-Linolenic acid can affect the process of thrombotic through the modulation of PI3K/Akt signaling. α-Linolenic acid possess the anti-arrhythmic properties and is related to cardiovascular disease and cancer[1]. α-Linolenic acid, isolated from Perilla frutescens, is an essential fatty acid that cannot be synthesized by humans. α-Linolenic acid can affect the process of thrombotic through the modulation of PI3K/Akt signaling. α-Linolenic acid possess the anti-arrhythmic properties and is related to cardiovascular disease and cancer[1]. α-Linolenic acid, isolated from Perilla frutescens, is an essential fatty acid that cannot be synthesized by humans. α-Linolenic acid can affect the process of thrombotic through the modulation of PI3K/Akt signaling. α-Linolenic acid possess the anti-arrhythmic properties and is related to cardiovascular disease and cancer[1].
Gamma-Linolenic acid
Gamma-linolenic acid is a C18, omega-6 acid fatty acid comprising a linolenic acid having cis- double bonds at positions 6, 9 and 12. It has a role as a human metabolite, a plant metabolite and a mouse metabolite. It is an omega-6 fatty acid and a linolenic acid. It is a conjugate acid of a gamma-linolenate. Gamolenic acid, or gamma-linolenic acid (γ-Linolenic acid) or GLA, is an essential fatty acid (EFA) comprised of 18 carbon atoms with three double bonds that is most commonly found in human milk and other botanical sources. It is an omega-6 polyunsaturated fatty acid (PUFA) also referred to as 18:3n-6; 6,9,12-octadecatrienoic acid; and cis-6, cis-9, cis-12- octadecatrienoic acid. Gamolenic acid is produced minimally in the body as the delta 6-desaturase metabolite of [DB00132]. It is converted to [DB00154], a biosynthetic precursor of monoenoic prostaglandins such as PGE1. While Gamolenic acid is found naturally in the fatty acid fractions of some plant seed oils, [DB11358] and [DB11238] are rich sources of gamolenic acid. Evening primrose oil has been investigated for clinical use in menopausal syndrome, diabetic neuropathy, and breast pain, where gamolenic acid is present at concentrations of 7-14\\\\\%. Gamolenic acid may be found in over-the-counter dietary supplements. Gamolenic acid is also found in some fungal sources and also present naturally in the form of triglycerides. Various clinical indications of gamolenic acid have been studied, including rheumatoid arthritis, atopic eczema, acute respiratory distress syndrome, asthma, premenstrual syndrome, cardiovascular disease, ulcerative colitis, ADHD, cancer, osteoporosis, diabetic neuropathy, and insomnia. gamma-Linolenic acid is a natural product found in Anemone cylindrica, Eurhynchium striatum, and other organisms with data available. Gamolenic Acid is a polyunsaturated long-chain fatty acid with an 18-carbon backbone and exactly three double bonds, originating from the 6th, 9th and 12th positions from the methyl end, with all double bonds in the cis- configuration. An omega-6 fatty acid produced in the body as the delta 6-desaturase metabolite of linoleic acid. It is converted to dihomo-gamma-linolenic acid, a biosynthetic precursor of monoenoic prostaglandins such as PGE1. (From Merck Index, 11th ed) gamma-Linolenic acid, also known as 18:3n6 or GLA, belongs to the class of organic compounds known as linoleic acids and derivatives. These are derivatives of linoleic acid. Linoleic acid is a polyunsaturated omega-6 18-carbon long fatty acid, with two CC double bonds at the 9- and 12-positions. gamma-Linolenic acid is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. gamma-Linolenic acid is an omega-6 fatty acid produced in the body as the delta 6-desaturase metabolite of linoleic acid. It is converted into dihomo-gamma-linolenic acid, a biosynthetic precursor of monoenoic prostaglandins such as PGE1 (PubChem). A C18, omega-6 acid fatty acid comprising a linolenic acid having cis- double bonds at positions 6, 9 and 12. gamma-Linolenic acid or GLA (γ-linolenic acid) (INN: gamolenic acid) is an n−6, or omega-6, fatty acid found primarily in seed oils. When acting on GLA, arachidonate 5-lipoxygenase produces no leukotrienes and the conversion by the enzyme of arachidonic acid to leukotrienes is inhibited. GLA is obtained from vegetable oils such as evening primrose (Oenothera biennis) oil (EPO), blackcurrant seed oil, borage seed oil, and hemp seed oil. GLA is also found in varying amounts in edible hemp seeds, oats, barley,[3] and spirulina.[4] Normal safflower (Carthamus tinctorius) oil does not contain GLA, but a genetically modified GLA safflower oil available in commercial quantities since 2011 contains 40\\\% GLA.[5] Borage oil contains 20\\\% GLA, evening primrose oil ranges from 8\\\% to 10\\\% GLA, and black-currant oil contains 15–20\\\%.[6] The human body produces GLA from linoleic acid (LA). This reaction is catalyzed by Δ6-desaturase (D6D), an enzyme that allows the creation of a double bond on the sixth carbon counting from the carboxyl terminus. LA is consumed sufficiently in most diets, from such abundant sources as cooking oils and meats. However, a lack of GLA can occur when there is a reduction of the efficiency of the D6D conversion (for instance, as people grow older or when there are specific dietary deficiencies) or in disease states wherein there is excessive consumption of GLA metabolites.[7] From GLA, the body forms dihomo-γ-linolenic acid (DGLA). This is one of the body's three sources of eicosanoids (along with AA and EPA.) DGLA is the precursor of the prostaglandin PGH1, which in turn forms PGE1 and the thromboxane TXA1. Both PGE11 and TXA1 are anti-inflammatory; thromboxane TXA1, unlike its series-2 variant, induces vasodilation, and inhibits platelet[8] consequently, TXA1 modulates (reduces) the pro-inflammatory properties of the thromboxane TXA2. PGE1 has a role in regulation of immune system function and is used as the medicine alprostadil. Unlike AA and EPA, DGLA cannot yield leukotrienes. However, it can inhibit the formation of pro-inflammatory leukotrienes from AA.[9] Although GLA is an n−6 fatty acid, a type of acid that is, in general, pro-inflammatory[citation needed], it has anti-inflammatory properties. (See discussion at Essential fatty acid interactions: The paradox of dietary GLA.) Gamma-linolenic acid (γ-Linolenic acid) is an omega-6 (n-6), 18 carbon (18C-) polyunsaturated fatty acid (PUFA) extracted from Perilla frutescens. Gamma-linolenic acid supplements could restore needed PUFAs and mitigate the disease[1]. Gamma-linolenic acid (γ-Linolenic acid) is an omega-6 (n-6), 18 carbon (18C-) polyunsaturated fatty acid (PUFA) extracted from Perilla frutescens. Gamma-linolenic acid supplements could restore needed PUFAs and mitigate the disease[1].
Linoleic acid
Linoleic acid is a doubly unsaturated fatty acid, also known as an omega-6 fatty acid, occurring widely in plant glycosides. In this particular polyunsaturated fatty acid (PUFA), the first double bond is located between the sixth and seventh carbon atom from the methyl end of the fatty acid (n-6). Linoleic acid is an essential fatty acid in human nutrition because it cannot be synthesized by humans. It is used in the biosynthesis of prostaglandins (via arachidonic acid) and cell membranes (From Stedman, 26th ed). Linoleic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism. Linoleic acid (LA) is an organic compound with the formula HOOC(CH2)7CH=CHCH2CH=CH(CH2)4CH3. Both alkene groups (−CH=CH−) are cis. It is a fatty acid sometimes denoted 18:2 (n-6) or 18:2 cis-9,12. A linoleate is a salt or ester of this acid.[5] Linoleic acid is a polyunsaturated, omega-6 fatty acid. It is a colorless liquid that is virtually insoluble in water but soluble in many organic solvents.[2] It typically occurs in nature as a triglyceride (ester of glycerin) rather than as a free fatty acid.[6] It is one of two essential fatty acids for humans, who must obtain it through their diet,[7] and the most essential, because the body uses it as a base to make the others. The word "linoleic" derives from Latin linum 'flax', and oleum 'oil', reflecting the fact that it was first isolated from linseed oil.
Arachidonic acid
Arachidonic acid is a polyunsaturated, essential fatty acid that has a 20-carbon chain as a backbone and four cis-double bonds at the C5, C8, C11, and C14 positions. It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. It is synthesized from dietary linoleic acid. Arachidonic acid mediates inflammation and the functioning of several organs and systems either directly or upon its conversion into eicosanoids. Arachidonic acid in cell membrane phospholipids is the substrate for the synthesis of a range of biologically active compounds (eicosanoids) including prostaglandins, thromboxanes, and leukotrienes. These compounds can act as mediators in their own right and can also act as regulators of other processes, such as platelet aggregation, blood clotting, smooth muscle contraction, leukocyte chemotaxis, inflammatory cytokine production, and immune function. Arachidonic acid can be metabolized by cytochrome p450 (CYP450) enzymes into 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs), their corresponding dihydroxyeicosatrienoic acids (DHETs), and 20-hydroxyeicosatetraenoic acid (20-HETE). The production of kidney CYP450 arachidonic acid metabolites is altered in diabetes, pregnancy, hepatorenal syndrome, and in various models of hypertension, and it is likely that changes in this system contribute to the abnormalities in renal function that are associated with many of these conditions. Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid (PMID: 12736897, 12736897, 12700820, 12570747, 12432908). The beneficial effects of omega-3 fatty acids are believed to be due in part to selective alteration of arachidonate metabolism that involves cyclooxygenase (COX) enzymes (PMID: 23371504). 9-Oxononanoic acid (9-ONA), one of the major products of peroxidized fatty acids, was found to stimulate the activity of phospholipase A2 (PLA2), the key enzyme to initiate the arachidonate cascade and eicosanoid production (PMID: 23704812). Arachidonate lipoxygenase (ALOX) enzymes metabolize arachidonic acid to generate potent inflammatory mediators and play an important role in inflammation-associated diseases (PMID: 23404351). Essential fatty acid. Constituent of many animal phospholipids Arachidonic acid. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=506-32-1 (retrieved 2024-07-15) (CAS RN: 506-32-1). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0). Arachidonic acid is an essential fatty acid and a major constituent of biomembranes. Arachidonic acid is an essential fatty acid and a major constituent of biomembranes.
Prostaglandin H2
Prostaglandin H2 (PGH2) is the first intermediate in the biosynthesis of all prostaglandins. Prostaglandins are synthesized from arachidonic acid by the enzyme COX-1 and COX-2, which are also called PGH synthase 1 and 2. These enzymes generate a reactive intermediate PGH2 which has a reasonably long half-life (90-100 s) but is highly lipophilic. PGH2 is converted into the biologically active prostaglandins by prostaglandin isomerases, yielding PGE2, PGD2, and PGF2, or by thromboxane synthase to make TXA2 or by prostacyclin synthase to make PGI2. Most nonsteroidal anti-inflammatory drugs such as aspirin and indomethacin inhibit both PGH synthase 1 and 2. A key feature for eicosanoid transcellular biosynthesis is the export of PGH2 or LTA4 from the donor cell as well as the uptake of these reactive intermediates by the acceptor cell. Very little is known about either process despite the demonstrated importance of both events. In cells, PGH2 rearranges nonenzymatically to LGs even in the presence of enzymes that use PGH2 as a substrate. When platelets form thromboxane A2 (TXA2) from endogenous arachidonic acid (AA), PGH2 reaches concentrations very similar to those of TXA2 and high enough to produce strong platelet activation. Therefore, platelet activation by TXA2 appears to go along with an activation by PGH2. The agonism of PGH2 is limited by the formation of inhibitory prostaglandins, especially PGD2 at higher concentrations. That is why thromboxane synthase inhibitors in PRP and at a physiological HSA concentration do not augment platelet activation (PMID: 2798452, 15650407, 16968946). Prostaglandins are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent and are able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis through receptor-mediated G-protein linked signalling pathways. Prostaglandin h2, also known as pgh2 or 9s,11r-epidioxy-15s-hydroxy-5z,13e-prostadienoate, is a member of the class of compounds known as prostaglandins and related compounds. Prostaglandins and related compounds are unsaturated carboxylic acids consisting of a 20 carbon skeleton that also contains a five member ring, and are based upon the fatty acid arachidonic acid. Thus, prostaglandin h2 is considered to be an eicosanoid lipid molecule. Prostaglandin h2 is practically insoluble (in water) and a weakly acidic compound (based on its pKa). Prostaglandin h2 can be found in a number of food items such as gooseberry, evergreen huckleberry, quince, and capers, which makes prostaglandin h2 a potential biomarker for the consumption of these food products. Prostaglandin h2 can be found primarily in human platelet tissue. In humans, prostaglandin h2 is involved in several metabolic pathways, some of which include magnesium salicylate action pathway, ketorolac action pathway, trisalicylate-choline action pathway, and salicylate-sodium action pathway. Prostaglandin h2 is also involved in a couple of metabolic disorders, which include leukotriene C4 synthesis deficiency and tiaprofenic acid action pathway. Prostaglandin h2 is acted upon by: Prostacyclin synthase to create prostacyclin Thromboxane-A synthase to create thromboxane A2 and 12-(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) (see 12-Hydroxyheptadecatrienoic acid) Prostaglandin D2 synthase to create prostaglandin D2 Prostaglandin E synthase to create prostaglandin E2 Prostaglandin h2 rearranges non-enzymatically to: A mixture of 12-(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) and 12-(S)-hydroxy-5Z,8Z,10E-heptadecatrienoic acid (see 12-Hydroxyheptadecatrienoic acid) Use of Prostaglandin H2: regulating the constriction and dilation of blood vessels stimulating platelet aggregation Effects of Aspirin on Prostaglandin H2: Aspirin has been hypothesized to block the conversion of arachidonic acid to Prostaglandin . D009676 - Noxae > D016877 - Oxidants > D010545 - Peroxides
Leukotriene A4
Leukotriene A4 (LTA4) is the first metabolite in the series of reactions leading to the synthesis of all leukotrienes. 5-Lipoxygenase (5-LO) catalyzes the two-step conversion of arachidonic acid to LTA4.The first step consists of the oxidation of arachidonic acid to the unstable intermediate 5-hydroperoxyeicosatetraenoic acid (5-HPETE), and the second step is the dehydration of 5-HPETE to form LTA4. Leukotriene A4, an unstable epoxide, is hydrolyzed to leukotriene B4 or conjugated with glutathione to yield leukotriene C4 and its metabolites, leukotriene D4 and leukotriene E4. The leukotrienes participate in host defense reactions and pathophysiological conditions such as immediate hypersensitivity and inflammation. Recent studies also suggest a neuroendocrine role for leukotriene C4 in luteinizing hormone secretion. (PMID: 10591081, 2820055). Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways. Leukotriene A4 (LTA4) is the first metabolite in the series of reactions leading to the synthesis of all leukotrienes. 5-Lipoxygenase (5-LO) catalyzes the two-step conversion of arachidonic acid to LTA4.The first step consists of the oxidation of arachidonic acid to the unstable intermediate 5-hydroperoxyeicosatetraenoic acid (5-HPETE), and the second step is the dehydration of 5-HPETE to form LTA4. Leukotriene A4, an unstable epoxide, is hydrolyzed to leukotriene B4 or conjugated with glutathione to yield leukotriene C4 and its metabolites, leukotriene D4 and leukotriene E4. The leukotrienes participate in host defense reactions and pathophysiological conditions such as immediate hypersensitivity and inflammation. Recent studies also suggest a neuroendocrine role for leukotriene C4 in luteinizing hormone secretion. (PMID: 10591081, 2820055)
Prostaglandin G2
Prostaglandin G2 (PGG2) is synthesized from arachidonic acid on a cyclooxygenase (COX) metabolic pathway as a primary step; the COX biosynthesis of prostaglandin (PG) begins with the highly specific oxygenation of arachidonic acid in the 11R configuration and ends with a 15S oxygenation to form PGG2. The COX site activity that catalyzes the conversion of arachidonic acid to PGG2 is the target for nonsteroidal antiinflammatory drugs (NSAIDs). The peroxidase site activity catalyzes the two-electron reduction of the hydroperoxide bond of PGG2 to yield the corresponding alcohol prostaglandin H2 (PGH2). The formation of a phenoxyl radical on Tyr385 couples the activities of the two sites. The Tyr385 radical is produced via oxidation by compound I, an oxoferryl porphyrin -cation radical, which is generated by reaction of the hemin resting state with PGG2 or other hydroperoxides. The tyrosyl radical homolytically abstracts the 13proS hydrogen atom of arachidonic acid which initiates a radical cascade that ends with the stereoselective formation of PGG2. PGG2 then migrates from the cyclooxygenase (COX) site to the peroxidase (POX) site where it reacts with the hemin group to generate PGH2 and compound I. The heterolytic oxygen-oxygen bond cleavage is assisted by the conserved distal residues His207 and Gln203, mutation of which has been shown to severely impair enzyme activity. Compound I, upon reaction with Tyr385, gives compound II, which in turn is reduced to the hemin resting state by one-electron oxidation of reducing cosubstrates or undergoes reactions that result in enzyme self-inactivation. Prostaglandin endoperoxide H synthase (PGHS) 1 is a bifunctional membrane enzyme of the endoplasmic reticulum that converts arachidonic acid into prostaglandin H2 (PGH2), the precursor of all prostaglandins, thromboxanes, and prostacyclins. These lipid mediators are intricately involved in normal physiology, namely, in mitogenesis, fever generation, pain response, lymphocyte chemotaxis, fertility, and contradictory stimuli such as vasoconstriction and vasodilatation, as well as platelet aggregation and quiescence. PGHS is implicated in numerous pathologies, including inflammation, cancers of the colon, lung, and breast, Alzheimers disease, Parkinsons disease, and numerous cardiovascular diseases including atherosclerosis, thrombosis, myocardial infarction, and stroke. (PMID: 14594816, 16552393, 16411757). Prostaglandins are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways. Prostaglandin G2 (PGG2) is synthesized from arachidonic acid on a cyclooxygenase (COX) metabolic pathway as a primary step; the COX biosynthesis of prostaglandin (PG) begins with the highly specific oxygenation of arachidonic acid in the 11R configuration and ends with a 15S oxygenation to form PGG2. D009676 - Noxae > D016877 - Oxidants > D010545 - Peroxides
Lipoxin B4
Lipoxins (LXs) and aspirin-triggered lipoxin (ATL) are trihydroxytetraene-containing eicosanoids generated from arachidonic acid that are distinct in structure, formation, and function from the many other proinflammatory lipid-derived mediators. These endogenous eicosanoids have now emerged as founding members of the first class of lipid/chemical mediators involved in the resolution of the inflammatory response. Lipoxin A4 (LXA4), ATL, and their metabolic stable analogs elicit cellular responses and regulate leukocyte trafficking in vivo by activating the specific receptor, ALX. Many of the eicosanoids derived from arachidonic acid (AA2), including prostaglandins (PGs) and leukotrienes (LTs), play important roles as local mediators exerting a wide range of actions relevant in immune hypersensitivity and inflammation. However, recent observations indicate that other agents derived from the lipoxygenase (LO) pathways are formed and play a key role in initiating the resolution of acute inflammation. This phenomenon is an active process that is governed by specific lipid mediators and involves a series of well-orchestrated temporal events. Thus, potent locally released mediators serve as checkpoint controllers of inflammation. In addition to the well-appreciated ability of aspirin to inhibit PGs, aspirin also acetylates cyclooxygenase (COX)-2, triggering the formation of a 15-epimeric form of lipoxins, termed aspirin-triggered LXA4 (ATL). These eicosanoids (i.e. LXA4 and ATL) with a unique trihydroxytetraene structure function as stop signals in inflammation and actively participate in dampening host responses to bring the inflammation to a close, namely, resolution. LXA4 and ATL elicit the multicellular responses via a specific G protein-coupled receptor (GPCR) termed ALX that has been identified in human (PMID: 16968948, 11478982). Lipoxins (LXs) and aspirin-triggered Lipoxin (ATL) are trihydroxytetraene-containing eicosanoids generated from arachidonic acid that are distinct in structure, formation, and function from the many other proinflammatory lipid-derived mediators. These endogenous eicosanoids have now emerged as founding members of the first class of lipid/chemical mediators involved in the resolution of the inflammatory response. Lipoxin A4 (LXA4), ATL, and their metabolic stable analogs elicit cellular responses and regulate leukocyte trafficking in vivo by activating the specific receptor, ALX. Many of the eicosanoids derived from arachidonic acid (AA2), including prostaglandins (PGs) and leukotrienes (LTs), play important roles as local mediators exerting a wide range of actions relevant in immune hypersensitivity and inflammation. However, recent observations indicate that other agents derived from the lipoxygenase (LO) pathways are formed and play a key role in initiating the resolution of acute inflammation. This phenomenon is an active process that is governed by specific lipid mediators and involves a series of well-orchestrated temporal events. Thus, potent locally released mediators serve as checkpoint controllers of inflammation. D018373 - Peripheral Nervous System Agents > D018689 - Sensory System Agents D002491 - Central Nervous System Agents > D000700 - Analgesics D000893 - Anti-Inflammatory Agents D018501 - Antirheumatic Agents
12(R)-HPETE
12(R)-HPETE is a hydroperoxyeicosatetraenoic acid eicosanoid derived from arachidonic acid. The epidermal lipoxygenases 12R-LOX and eLOX3 act in sequence to convert arachidonic acid via 12(R)-HPETE to 12(R)-HETE and the corresponding epoxyalcohol, 8(R)-hydroxy-11(R),12(R)-epoxyeicosatrienoic acid. The epidermal lipoxygenases 12R-LOX and eLOX3 are the gene products of ALOX12B and ALOXE3. Mutations in ALOXE3 or ALOX12B have been found in families with autosomal-recessive congenital ichthyosis (ARCI). ARCI is a clinically and genetically heterogeneous group of severe hereditary keratinization disorders characterized by intense scaling of the whole integument, and differences in color and shape, often associated with erythema. Mutations in ALOXE3 and ALOX12B on chromosome 17p13, which code for two different epidermal lipoxygenases, were found in patients with ichthyosiform erythroderma. Genetic studies indicated that 12R-lipoxygenase (12R-LOX) or epidermal lipoxygenase-3 (eLOX3) was mutated in six families affected by non-bullous congenital ichthyosiform erythroderma (NCIE), one of the main clinical forms of ichthyosis. (PMID: 16116617, 15629692). 12(R)-HPETE is a hydroperoxyeicosatetraenoic acid eicosanoid derived from arachidonic acid. The epidermal lipoxygenases 12R-LOX and eLOX3 act in sequence to convert arachidonic acid via 12(R)-HPETE to 12(R)-HETE and the corresponding epoxyalcohol, 8(R)-hydroxy-11(R),12(R)-epoxyeicosatrienoic acid.
5-HPETE
Arachidonic acid 5-hydroperoxide (5-hydroperoxyeicosatetraenoic acid, 5-HPETE) is an intermediate in the production of leukotriene A4 from arachidonic acid. [HMDB] Arachidonic acid 5-hydroperoxide (5-hydroperoxyeicosatetraenoic acid, 5-HPETE) is an intermediate in the production of leukotriene A4 from arachidonic acid.
12-HEPE
12-HEPE is hydroxy derivative of 12-lipoxygenase metabolites of Eicosapentaenoic acid (EPA). 12S-HEPE participates in platelet-neutrophil interactions in a manner similar to 12S-HETE. It can also compete with endogenous arachidonic acid for 5-lipoxygenation in stimulated human neutrophils. By providing competing substrates for neutrophil 5-lipoxygenase, platelets might contribute to the antiinflammatory potential of dietary n-3 fatty acids through platelet-neutrophil interaction. ( PMID: 2116491) [HMDB] 12-HEPE is hydroxy derivative of 12-lipoxygenase metabolites of Eicosapentaenoic acid (EPA). 12S-HEPE participates in platelet-neutrophil interactions in a manner similar to 12S-HETE. It can also compete with endogenous arachidonic acid for 5-lipoxygenation in stimulated human neutrophils. By providing competing substrates for neutrophil 5-lipoxygenase, platelets might contribute to the antiinflammatory potential of dietary n-3 fatty acids through platelet-neutrophil interaction. ( PMID: 2116491).
15-HEPE
15-HEPE has been identified as a possible anti-inflammatory metabolite, and its elevated presence in the epidermis of animals fed oils rich in 20:5(n-3) or 18:3(n-6) may provide a mechanism for the beneficial effects of these oils on inflammatory conditions. 15-HEPE is a metabolite of eicosapentaenoic acid (EPA) which has anti-inflammatory properties and plays an important role in the resolution phase of inflammation. 15-HEPE is deposited in the epidermis, particularly in the metabolically active basal layer. This is considered advantageous in psoriasis therapy. (PMID: 17540633, 2106017) [HMDB] 15-HEPE has been identified as a possible anti-inflammatory metabolite, and its elevated presence in the epidermis of animals fed oils rich in 20:5(n-3) or 18:3(n-6) may provide a mechanism for the beneficial effects of these oils on inflammatory conditions. 15-HEPE is a metabolite of eicosapentaenoic acid (EPA) which has anti-inflammatory properties and plays an important role in the resolution phase of inflammation. 15-HEPE is deposited in the epidermis, particularly in the metabolically active basal layer. This is considered advantageous in psoriasis therapy. (PMID: 17540633, 2106017).