linoleic acid (LA), a carboxylic acid, is a polyunsaturated omega-6 fatty acid, an 18-carbon chain with two double bonds in a cis configuration. Short notations such as "18: 2 (n-6)" or "18: 2 cis -9,12" can be used in the literature. It usually occurs in nature as a triglyceride ester; free fatty acids are usually low in food.
Linoleic acid is one of two essential fatty acids, meaning that the human body can not synthesize it from other food components.
The word "linoleic" comes from the Greek word linon (hemp). Oleic means "from, related to, or derived from olive oil" or "from or related to oleic acid" because saturating the double bonds of omega-6 produces oleic acid.
Video Linoleic acid
Dalam fisiologi
LA is a polyunsaturated fatty acid used in the biosynthesis of arachidonic acid (AA) and thus some prostaglandins, leukotrienes (LTA, LTB, LTC), and thromboxane (TXA). It is found in lipid cell membranes. There are many nuts, fatty seeds (flaxseed, flaxseed, poppy seeds, sesame seeds, etc.) and their vegetable oils; consists of more than half (weight) of poppy seeds, safflower, sunflower, corn, and soybean oil.
LA is altered by various lipoxygenases, cyclooxygenases, certain cytochrome P450 enzymes (monooxygenase CYP), and non-enzymatic autochemical mechanisms for mono-hydroxyl products, 13-Hydroxyoctadecadienoic acid and 9-Hydroxyoctadecadienoic acid; both of these hydroxy metabolites are enzymatically oxidized to their keto metabolites, 13-oxo-octadecanoic acid and 9-oxo-octecdienoic acid. Certain Cytochrome P450 enzymes, CYP epoxygenases, metabolize LA into epoxide products ie, 12.13-epoxide, Vernolic acid and 9,10-epoxide, Coronaric acid. All of these LA products have bioactivity and are involved in human physiology and pathology as shown in the cited link.
Linoleic acid is an essential fatty acid that must be consumed for proper health. Diet deficiency in linoleic (salt form of acid) causes mild skin scaling, hair loss, and poor wound healing in rats.
Together with oleic acid, linoleic acid is released by the cockroach at the time of death which has the effect of preventing other cockroaches entering the area. This is similar to the mechanism found in ants and bees, which also release oleic acid at the time of death.
LA is associated with Ulcerative Colitis.
Metabolism and eicosanoid
The first step in LA metabolism is done by? 6 desaturase, which transforms LA into gamma-Linolenic acid (GLA).
There is evidence to suggest that infants lack their own 6 desaturase, and should get it through breast milk. Studies show that breast-fed infants have higher GLA concentrations than formula-fed infants, while formula-fed infants have high LA concentrations.
GLA changed to dihomo -? - linolenic acid (DGLA), which in turn is converted to arachidonic acid (AA). One possible fate of AA is to turn into a metabolite group called eicosanoids during an inflammatory response and during physical activity; eicosanoid is the paracrine hormone class. Three types of eikosanoid are prostaglandins, thromboxane, and leukotrienes. Eicosanoids produced from AA tend to promote inflammation and increase growth during and after physical activity in healthy humans. For example, both thrombaxane derived from AA and leukotriene B4 are proaggregatory and vasoconstrictive eicosanoids during inflammation. Oxidized metabolic products of linoleic acid, such as 9-hydroxyoctadecanoic acid and 13-hydroxyoctadecanoic, have also been shown to activate TRPV1, the capsaicin receptor, and through this may play a major role in hyperalgesia and allodynia.
There are some suggested negative health effects associated with the inflammatory function of promoting linoleic acid as an omega-6 fatty acid.
Maps Linoleic acid
Usage
Industrial use
Linoleic acid is used to make quick dry oil, which is useful in oil paints and varnishes. This application exploits the easy reaction of linoleic acid with oxygen in the air, leading to crosslinking and stable film formation called linoxyn.
The reduction of linoleic acid produces linolenyl alcohol. Linoleic acid is a surfactant with a critical micelle concentration of 1.5 x 10 -4 M @ pH 7.5.
Linoleic acid has become increasingly popular in the beauty products industry because of its beneficial properties on the skin. Research shows anti-inflammatory properties, acne removal, skin-lightness and moist acid linoleic acid when applied topically on the skin.
Use in research
Radical linoleic acid lipids can be used to show the antioxidant effects of polyphenols and natural phenols. Experiments on linoleic acid were subjected to 2,2'-Azobis (2-amidinopropane) dihydrochloride induced oxidation of linoleic acid; then producing lipid radicals and then the use of different combinations of phenolates indicates that binary mixtures can cause synthetic antioxidant effects or antagonistic effects on lipid radicals. Such studies are useful in finding phenols that prevent lipid autoksidation in vegetable oils.
Food source
Note: Unless mentioned, none of this percentage has been verified by scientific research.
See also
- Conjugated linoleic acid
- Omega-6 fatty acid: Negative health effects
- Essential fatty acids
- The interaction of essential fatty acids
- Eicosanoids
- Essential nutrients
- Linolein
References
External links
- Linoleic MS Spectrum Acid
- Fatty Acids: Methylene-Discontinued Double Bonds, AOCS Lipid Library
Source of the article : Wikipedia
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