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CAS Number: 20590-32-3
Chemical formula: C20H34O2
Molar mass: 306.48276 g/mol
Preferred IUPAC name: (5Z,8Z,11Z)-Icosa-5,8,11-trienoic acid
Mead acid is an omega-9 fatty acid, first characterized by James F. Mead.
As with some other omega-9 polyunsaturated fatty acids, animals can make Mead acid de novo.
Its elevated presence in the blood is an indication of essential fatty acid deficiency.
Mead acid is found in large quantities in cartilage.
APPLICATIONS
Mead acid (5,8,11-Eicosatrienoic acid), an unsaturated (Omega-9) fatty acid, is an indicator of essential fatty acid deficiency.
Mead acid is an omega-9 fatty acid.
Like some other omega-9 polyunsaturated fatty acids animals can make Mead acid de novo.
Its elevated presence in the blood is an indication of essential fatty acid deficiency. Mead acid is found in large quantities in cartilage.
Mead Acid is an omega-9 fatty acid and anti-inflammatory precursor in the biosynthesis of prostaglandins, thromboxanes and leukotrienes.
-Role in inflammation
Cyclooxygenases are enzymes known to play a large role in inflammatory processes through oxidation of unsaturated fatty acids, most notably, the formation of prostaglandin H2 from arachidonic acid (AA).
AA has the same chain length as Mead acid but an additional ω-6 double bond.
When physiological levels of arachidonic acid are low, other unsaturated fatty acids including mead and linoleic acid are oxidized by COX.
Cyclooxygenase breaks the bisallylic C-H bond of AA to synthesize prostaglandin H2, but breaks a stronger allylic C-H bond when it encounters Mead acid instead.
Mead acid is also converted to leukotrienes C3 and D3.
Mead acid is metabolized by 5-lipoxygenase to 5-hydroxyeicosatrieonic acid (5-HETrE) and then by 5-Hydroxyeicosanoid dehydrogenase to 5-oxoeicosatrienoic acid (5-oxo-ETrE).
5-Oxo-ETrE is as potent as its arachidonic acid-derived analog, 5-oxo-eicosatetraenoic acid (5-oxo-ETE), in stimulating human blood eosinophils and neutrophils; it presumably does so by binding to the 5-oxo-ETE receptor (OXER1) and therefore may be, like 5-oxo-ETE, a mediator of human allergic and inflammatory reactions.
DESCRIPTION
Mead acid is an omega-9 fatty acid, first characterized by James F. Mead.
Mead Acid is also known as cis-5,8,11-Eicosatrienoic acid.
As with some other omega-9 polyunsaturated fatty acids, animals can make Mead acid de novo.
Its elevated presence in the blood is an indication of essential fatty acid deficiency.
Mead acid is found in large quantities in cartilage.
Mead acid, also referred to as eicosatrienoic acid, is chemically a carboxylic acid with a 20-carbon chain and three methylene-interrupted cis double bonds, as is typical for polyunsaturated fatty acids.
The first double bond is located at the ninth carbon from the omega end.
In the presence of lipoxygenase, cytochrome p450, or cyclooxygenase, mead acid can form various hydroxyeicosatetraenoic acid (HETE) and hydroperoxy (HpETE) products.
Mead Acid is a polyunsaturated long-chain fatty acid with a 20-carbon backbone and 3 double bonds, originating from the 9th, 12th and 15th positions from the methyl end, with all bonds in the cis- configuration.
Mead Acid is an icosatrienoic acid with three cis-double bonds at positions 5, 8 and 11. It is a conjugate acid of a (5Z,8Z,11Z)-icosatrienoate.
In mammals, Mead Acid is synthesized from oleic acid during a state of essential fatty acid deficiency (EFAD).
Mead acid is thought to be produced by the same enzymes that synthesize arachidonic acid and eicosapentaenoic acid, but the genes and the pathways involved in the conversion of oleic acid to Mead acid have not been fully elucidated.
The levels of polyunsaturated fatty acids in cultured cells are generally very low compared to those in mammalian tissues.
PHYSIOLOGY
Two fatty acids, linoleic acid and alpha-linolenic acid, are considered essential fatty acids (EFAs) in humans and other mammals.
Both are 18 carbon fatty acids unlike mead acid, which has 20 carbons. Linoleic is an ω-6 fatty acid whereas linolenic is ω-3 and mead is ω-9.
One study examined patients with intestinal fat malabsorption and suspected EFA deficiency; they were found to have blood-levels of mead acid about 13-fold higher than reference subjects.
Under severe conditions of essential fatty acid deprivation, mammals will elongate and desaturate oleic acid to make mead acid, (20:3, n−9).
This has been documented to a lesser extent in vegetarians and semi-vegetarians following an unbalanced diet.
Mead acid has been found to decrease osteoblastic activity. This may be important in treating conditions where inhibition of bone formation is desired.
SYNTHESIS OF MEAD ACID
In animals, it can be produced de novo from oleic acid (18:2n-6).
The enzymes that catalyze the conversion of oleic acid (18:1n-9), linoleic acid (18:2n-6) and alpha-linolenic acid (18:2n-3) to the C20 n-9, omega-6 polyunsaturated fatty acids and omega-3 polyunsaturated fatty acids are the same but omega-6 and omega-3 families have greater affinity for them than does the omega-9; from a biochemical point of view this is competitive inhibition.
In essential fatty acid deficiency competitive inhibition is lack and enzymes will desaturate oleic acid to 18:2n-9 (Δ6 desaturase), which is further elongated and Δ5 desaturated to form Mead acid.
SYNONYMS
(5Z,8Z,11Z)-Icosa-5,8,11-trienoic acid
20590-32-3
5Z,8Z,11Z-eicosatrienoic acid
cis-5,8,11-Eicosatrienoic acid
(5Z,8Z,11Z)-icosa-5,8,11-trienoic acid
