Độc tính so sánh axit oleic và axit linoleic đối với tế bào Raji
axit oleic và axit linoleic kháng Raji
Oleic acid
From Wikipedia, the free encyclopedia
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| Names | |
|---|---|
| Preferred IUPAC name
(9Z)-Octadec-9-enoic acid
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| Other names
Oleic acid
(9Z)-Octadecenoic acid (Z)-Octadec-9-enoic acid cis-9-Octadecenoic acid cis-Δ9-Octadecenoic acid 18:1 cis-9 | |
| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.003.643 |
| Properties | |
| C18H34O2 | |
| Molar mass | 282.47 g·mol−1 |
| Appearance | Pale yellow or brownish yellow oily liquid with lard-like odor |
| Density | 0.895 g/mL |
| Melting point | 13 to 14 °C (55 to 57 °F; 286 to 287 K) |
| Boiling point | 195 °C (383 °F; 468 K)[1] |
| Insoluble | |
| Solubility in Ethanol | Soluble |
| -208.5·10−6 cm3/mol | |
| Hazards | |
| Safety data sheet | JT Baker |
| NFPA 704 | |
| Related compounds | |
Related compounds
| Elaidic acid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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| Infobox references | |
Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated omega-9 fatty acid, abbreviated with a lipid number of 18:1 cis-9. It has the formula CH3(CH2)7CH=CH(CH2)7COOH.[2] The term "oleic" means related to, or derived from, olive oil which is predominantly composed of oleic acid.
Contents
[hide]Occurrence[edit]
Fatty acids (or their salts) do not often occur as such in biological systems. Instead fatty acids like oleic acid occur as their esters, commonly triglycerides, which are the greasy materials in many natural oils. Fatty acids can be obtained via the process of saponification.
Triglycerides of oleic acid compose the majority of olive oil, although there may be less than 2.0% as free acid in virgin olive oil, with higher concentrations making the olive oil inedible.[3] It also makes up 59-75% of pecan oil,[4] 61% of canola oil,[5] 36-67% of peanut oil,[6] 60% of macadamia oil, 20-85% of sunflower oil (the latter in the high oleic variant),[7] 15-20% of grape seed oil, sea buckthorn oil, and sesame oil,[2] and 14% of poppyseed oil. It is abundantly present in many animal fats, constituting 37 to 56% of chicken and turkey fat[8] and 44 to 47% of lard.
Oleic acid is the most abundant fatty acid in human adipose tissue,[9] and second in abundance in human tissues overall only to palmitic acid.[10]
As an insect pheromone[edit]
Oleic acid is emitted by the decaying corpses of a number of insects, including bees and Pogonomyrmex ants, and triggers the instincts of living workers to remove the dead bodies from the hive. If a live bee[11] or ant[12][13] is dabbed with oleic acid, it is dragged off for disposal as if it were dead. The oleic acid smell also may indicate danger to living insects, prompting them to avoid others who have succumbed to disease or places where predators lurk.[14]
Production and chemical behavior[edit]
The biosynthesis of oleic acid involves the action of the enzyme stearoyl-CoA 9-desaturase acting on stearoyl-CoA. In effect, stearic acid is dehydrogenated to give the monounsaturated derivative oleic acid.
Oleic acid undergoes the reactions of carboxylic acids and alkenes. It is soluble in aqueous base to give soaps called oleates. Iodine adds across the double bond. Hydrogenation of the double bond yields the saturated derivative stearic acid. Oxidation at the double bond occurs slowly in air, and is known as rancidification in foodstuffs or drying in coatings. Reduction of the carboxylic acid group yields oleyl alcohol. Ozonolysis of oleic acid is an important route to azelaic acid. The coproduct is nonanoic acid:[15]
- H17C8CH=CHC7H14CO2H + 4"O" → H17C8CO2H + HO2CC7H14CO2H
Esters of azelaic acid find applications in lubrication and plasticizers.
Related compounds[edit]
The stereoisomer of oleic acid is called elaidic acid or trans-9-octadecenoic acid. These isomers have distinct physical properties and biochemical properties. Elaidic acid, the most abundant trans fatty acid in diet, appears to have an adverse effect on health.[16] A reaction that converts oleic acid to elaidic acid is called elaidinization.
Another naturally occurring isomer of oleic acid is petroselinic acid.
In chemical analysis, fatty acids are separated by gas chromatography of their methyl ester derivatives. Alternatively, separation of unsaturated isomers is possible by argentation thin-layer chromatography.[17]
Uses[edit]
The principal use of oleic acid is as a component in many foods, in the form of its triglycerides. It is a component of the normal human diet as a part of animal fats and vegetable oils.
Oleic acid as its sodium salt is a major component of soap as an emulsifying agent. It is also used as an emollient.[18] Small amounts of oleic acid are used as an excipient in pharmaceuticals, and it is used as an emulsifying or solubilizing agent in aerosol products.[19]
Niche uses[edit]
Oleic acid is also used to induce lung damage in certain types of animals, for the purpose of testing new drugs and other means to treat lung diseases. Specifically in sheep, intravenous administration of oleic acid causes acute lung injury with corresponding pulmonary edema.[20] This sort of research has been of particular benefit to premature newborns, for whom treatment for underdeveloped lungs (and associated complications) is often a matter of life and death.[citation needed]
Oleic acid is used as a soldering flux in stained glass work for joining lead came.[21]
Health effects[edit]
Oleic acid is a common monounsaturated fat in human diet. Monounsaturated fat consumption has been associated with decreased low-density lipoprotein (LDL)cholesterol, and possibly increased high-density lipoprotein (HDL) cholesterol.[22] However, its ability to raise HDL is still debated.
Oleic acid may be responsible for the hypotensive (blood pressure reducing) effects of olive oil.[23] Adverse effects also have been documented, however, since both oleic and monounsaturated fatty acid levels in the membranes of red blood cells have been associated with increased risk of breast cancer,[24] although the consumption of oleate in olive oil has been associated with a decreased risk of breast cancer.[25]
Linoleic acid
From Wikipedia, the free encyclopedia
(Redirected from Linoleic)
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| Names | |
|---|---|
| IUPAC name
(9Z,12Z)-9,12-Octadecadienoic acid
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| Other names
C18:2 (Lipid numbers)
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| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.000.428 |
| KEGG | |
| UNII | |
| Properties | |
| C18H32O2 | |
| Molar mass | 280.45 g·mol−1 |
| Appearance | Colorless oil |
| Density | 0.9 g/cm3[1] |
| Melting point | −5 °C (23 °F)[2] −12 °C (10 °F)[1] |
| Boiling point | 230 °C (446 °F) at 21 mbar[2] 230 °C (446 °F) at 16 mmHg[1] |
| 0.139 mg/L[2] | |
| Vapor pressure | 16 Torr at 229 °C[citation needed] |
| Hazards | |
| NFPA 704 | |
| Flash point | 112 °C (234 °F)[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 verify (what is ?) | |
| Infobox references | |
Linoleic acid (LA) is a polyunsaturated omega-6 fatty acid. It is a colorless liquid at room temperature. In physiological literature, it has a lipid number of 18:2 cis,cis-9,12. Linoleic acid is a carboxylic acid with an 18-carbon chain and two cis double bonds; with the first double bond located at the sixth carbon from the methyl end.[3]
Linoleic acid belongs to one of the two families of essential fatty acids, which means that the human body cannot synthesize it from other food components.[4]
The word "linoleic" derived from the Greek word linon (flax). Oleic means "of, relating to, or derived from oil of olive" or "of or relating to oleic acid" because saturating the omega-6 double bond produces oleic acid.
Contents
[hide]In physiology[edit]
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 the lipids of cell membranes. It is abundant in many nuts, fatty seeds (flax seeds, hemp seeds, poppy seeds, sesame seeds, etc.) and their derived vegetable oils; comprising over half (by weight) of poppy seed, safflower, sunflower, corn, and soybean oils.[5]
LA is converted by various lipoxygenases, cyclooxygenases, certain cytochrome P450 enzymes (the CYP monooxygenases), and non-enzymatic autooxidation mechanisms to mono-hydroxyl products viz., 13-Hydroxyoctadecadienoic acid and 9-Hydroxyoctadecadienoic acid; these two hydroxy metabolites are enzymatically oxidized to their keto metabolites, 13-oxo-octadecadienoic acid and 9-oxo-octadecdienoic acid. Certain cytochrome P450 enzymes, the CYP epoxygenases, metabolize LA to epoxide products viz., its 12,13-epoxide, Vernolic acidand its 9,10-epoxide, Coronaric acid. All of these LA products have bioactivity and are implicated in human physiology and pathology as indicated in the cited linkages.
Linoleic acid is an essential fatty acid that must be consumed for proper health. A diet only deficient in linoleate (the salt form of the acid) causes mild skin scaling, hair loss,[6] and poor wound healing in rats.[7]
Along with oleic acid, linoleic acid is released by cockroaches upon death which has the effect of preventing other roaches from entering the area. This is similar to the mechanism found in ants and bees, which also release oleic acid upon death.[8]
Metabolism and eicosanoids[edit]
The first step in the metabolism of LA is performed by Δ6desaturase, which converts LA into gamma-linolenic acid (GLA).
There is evidence suggesting that infants lack Δ6desaturase of their own, and must acquire it through breast milk. Studies show that breast-milk fed babies have higher concentrations of GLA than formula-fed babies, while formula-fed babies have elevated concentrations of LA.[9]
GLA is converted to dihomo-gamma-linolenic acid (DGLA), which in turn is converted to arachidonic acid (AA). One of the possible fates of AA is to be transformed into a group of metabolites called eicosanoids during the inflammatory response and during physical activity; eicosanoids are a class of paracrine hormones. The three types of eicosanoids are prostaglandins, thromboxanes, and leukotrienes. Eicosanoids produced from AA tend to promote (not cause) inflammation and promotegrowth during and after physical activity in healthy humans.[10] For example, both AA-derived thrombaxane and leukotrieneB4 are proaggregatory and vasoconstrictive eicosanoids during inflammation. The oxidized metabolic products of linoleic acid, such as 9-hydroxyoctadecanoic acid and 13-hydroxyoctadecanoic acid, have also been shown to activate TRPV1, the capsaicin receptor, and through this might play a major role in hyperalgesia and allodynia.[11]
There are some suggested negative health effects related to this inflammation promoting function of linoleic acid as an omega-6 fatty acid.
Uses[edit]
Industrial uses[edit]
Linoleic acid is used in making quick-drying oils, which are useful in oil paints and varnishes. These applications exploit the easy reaction of the linoleic acid with oxygen in air, which leads to crosslinking and formation of a stable film called linoxyn.
Reduction of linoleic acid yields linoleyl 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 points to linoleic acid's anti-inflammatory, acne reductive, and moisture retentive properties when applied topically on the skin.[12][13][14]
Use in research[edit]
Linoleic acid lipid radicals can be used to show the antioxidant effect of natural phenols. Experiments on linoleic acid subjected to 2,2′-azobis (2-amidinopropane) dihydrochloride induced oxidation of linoleic acid; hence producing lipid radicals and then the use of different combinations of phenolics show that binary mixtures can lead to either a synergetic antioxidant effect or to an antagonistic effect towards the lipid radicals. Research like this is useful in discovering which phenols prevent the autoxidation of lipids in vegetable oils.[15]
Dietary sources[edit]
Note: Unless cited, none of these percentages have been verified by scientific research.
| Name | % LA† | ref. |
|---|---|---|
| Salicornia oil | 75% | |
| Safflower oil | 74.62% | |
| Evening Primrose oil | 73% | |
| Poppyseed oil | 70% | |
| Grape seed oil | 69.6% | |
| Sunflower oil | 65.7% | |
| Barbary Fig Seed Oil | 65% | |
| Hemp oil | 54.3% | [16] |
| Corn oil | 59% | |
| Wheat germ oil | 55% | |
| Cottonseed oil | 54% | |
| Soybean oil | 51% | |
| Walnut oil | 51% | |
| Sesame oil | 45% | |
| Rice bran oil | 39% | |
| Argan oil | 37% | |
| Pistachio oil | 32.7% | |
| Peanut oil | 32% | [17] |
| Peach oil | 29% | [18] |
| Almonds | 24% | |
| Canola oil | 21% | |
| Chicken fat | 18-23% | [19] |
| Egg yolk | 16% | |
| Linseed oil | 15% | |
| Lard | 10% | |
| Olive oil | 10% (3.5 - 21%) | [20][21] |
| Palm oil | 10% | |
| Cocoa butter | 3% | |
| Macadamia oil | 2% | |
| Butter | 2% | |
| Coconut oil | 2% | |
| †average val | ||
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