Axit Palmitic và chuyển hóa acid linoleic trong tế bào Caco-2
https://dspace.library.uu.nl/handle/1874/293993
Palmitic acid and linoleic acid kháng Caco-2
Linoleic acid
From Wikipedia, the free encyclopedia
 | |
 | |
 | |
| Names | |
|---|---|
| IUPAC name
(9Z,12Z)-9,12-Octadecadienoic acid
| |
| Other names
C18:2 (Lipid numbers)
| |
| Identifiers | |
3D model (JSmol)
| |
| 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).
| |
 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 | ||
See also[edit]
- Conjugated linoleic acid
- Omega-6 fatty acid: Negative health effects
- Essential fatty acids
- Essential fatty acid interactions
- Eicosanoids
- Essential nutrients
- Linolein
Palmitic acid
From Wikipedia, the free encyclopedia
 | |
 | |
| Names | |
|---|---|
| Preferred IUPAC name
Hexadecanoic acid
| |
| Other names
Palmitic acid
C16:0 (Lipid numbers) | |
| Identifiers | |
3D model (JSmol)
| |
| ChemSpider | |
| ECHA InfoCard | 100.000.284 |
PubChem CID
| |
| Properties | |
| C16H32O2 | |
| Molar mass | 256.43 g·mol−1 |
| Appearance | white crystals |
| Density | 0.852 g/cm3 (25 °C)[2] 0.8527 g/cm3 (62 °C)[3] |
| Melting point | 62.9 °C (145.2 °F; 336.0 K) [8] |
| Boiling point | 351–352 °C (664–666 °F; 624–625 K) [4] 271.5 °C (520.7 °F; 544.6 K) at 100 mmHg[2] 215 °C (419 °F; 488 K) at 15 mmHg |
| 0.46 mg/L (0 °C) 0.719 mg/L (20 °C) 0.826 mg/L (30 °C) 0.99 mg/L (45 °C) 1.18 mg/L (60 °C)[5] | |
| Solubility | soluble in amyl acetate, alcohol, CCl4,[5] C6H6 very soluble in CHCl3[3] |
| Solubility in ethanol | 2 g/100 mL (0 °C) 2.8 g/100 mL (10 °C) 9.2 g/100 mL (20 °C) 31.9 g/100 mL (40 °C)[6] |
| Solubility in methyl acetate | 7.81 g/100 g[5] |
| Solubility in ethyl acetate | 10.7 g/100 g[5] |
| Vapor pressure | 0.051 mPa (25 °C)[3] 1.08 kPa (200 °C) 28.06 kPa (300 °C)[7] |
| Acidity (pKa) | 4.75 [3] |
| -198.6·10−6 cm3/mol | |
Refractive index(nD)
| 1.43 (70 °C)[3] |
| Viscosity | 7.8 cP (70 °C)[3] |
| Thermochemistry | |
| 463.36 J/mol·K[7] | |
Std molar
entropy (S | 452.37 J/mol·K[7] |
Std enthalpy of
formation (ΔfH | -892 kJ/mol[7] |
Std enthalpy of
combustion(ΔcH | 10030.6 kJ/mol[3] |
| Hazards | |
| GHS pictograms |  [2] |
| GHS signal word | Warning |
| H319[2] | |
| P305+351+338[2] | |
| NFPA 704 | |
| Flash point | 206 °C (403 °F; 479 K) [2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
 verify (what is ?) | |
| Infobox references | |
Palmitic acid, or hexadecanoic acid in IUPAC nomenclature, is the most common saturated fatty acid found in animals, plants and microorganisms.[9] Its chemical formula is CH3(CH2)14COOH. As its name indicates, it is a major component of the oil from the fruit of oil palms (palm oil). Palmitic acid can also be found in meats, cheeses, butter, and dairy products. Palmitate is a term for the salts and esters of palmitic acid. The palmitate anion is the observed form of palmitic acid at physiologic pH (7.4).
Aluminium salts of palmitic acid and naphthenic acid were combined during World War II to produce napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid.
Contents
[hide]Occurrence and production[edit]
Palmitic acid was discovered by Edmond Frémy in 1840, in saponified palm oil.[10] This remains the primary industrial route for its production, with the triglycerides (fats) in palm oil being hydrolysed by high temperature water (above 200 °C or 390 °F), and the resulting mixture fractionally distilled to give the pure product.[11]
Palmitic acid is naturally produced by a wide range of other plants and organisms, typically at low levels. It is naturally present in butter, cheese, milk, and meat , as well as cocoa butter, soybean oil, and sunflower oil. The cetyl ester of palmitic acid (cetyl palmitate) occurs in spermaceti.
Biochemistry[edit]
Excess carbohydrates in the body are converted to palmitic acid. Palmitic acid is the first fatty acid produced during fatty acid synthesis and is the precursor to longer fatty acids. As a consequence, palmitic acid is a major body component of animals. In humans, one analysis found it to make up 21–30% (molar) of human depot fat,[12] and it is a major, but highly variable, lipid component of human breast milk.[13] Palmitate negatively feeds back on acetyl-CoA carboxylase (ACC), which is responsible for converting acetyl-CoA to malonyl-CoA, which in turn is used to add to the growing acyl chain, thus preventing further palmitate generation.[14] In biology, some proteins are modified by the addition of a palmitoyl group in a process known as palmitoylation. Palmitoylation is important for membrane localisation of many proteins.
Applications[edit]
Palmitic acid is used to produce soaps, cosmetics, and industrial mold release agents. These applications use sodium palmitate, which is commonly obtained by saponification of palm oil. To this end, palm oil, rendered from palm tree (species Elaeis guineensis), is treated with sodium hydroxide (in the form of caustic soda or lye), which causes hydrolysisof the ester groups. This procedure affords glycerol and sodium palmitate.
Because it is inexpensive and adds texture and "mouth feel" to processed foods (convenience food), palmitic acid and its sodium salt find wide use in foodstuffs. Sodium palmitate is permitted as a natural additive in organic products.[15] The aluminium salt is used as a thickening agent of napalm used in military actions.
Hydrogenation of palmitic acid yields cetyl alcohol, which is used to produce detergents and cosmetics.
Recently, a long-acting antipsychotic medication, paliperidone palmitate (marketed as INVEGA Sustenna), used in the treatment of schizophrenia, has been synthesized using the oily palmitate ester as a long-acting release carrier medium when injected intramuscularly. The underlying method of drug delivery is similar to that used with decanoic acid to deliver long-acting depot medication, in particular, neuroleptics such as haloperidol decanoate.
Health effects[edit]
According to the World Health Organization, evidence is "convincing" that consumption of palmitic acid increases the risk of developing cardiovascular disease,[16] based on studies indicating that it may increase LDL levels in the blood. Retinyl palmitate is an antioxidant and a source of vitamin A added to low fat milk to replace the vitamin content lost through the removal of milk fat. Palmitate is attached to the alcohol form of vitamin A, retinol, to make vitamin A stable in milk.
Rats fed a diet of 20% palmitic acid and 80% carbohydrate for extended periods showed alterations in central nervous system control of insulin secretion, and suppression of the body's natural appetite-suppressing signals from leptin and insulin (the key hormones involved in weight regulation).[17]
Palmitic acid strongly boosts metastasis in mouse models of human oral cancer cells. Among all fatty acids, it has the strongest effect in boosting the metastatic potential of CD36+ metastasis-initiating cells.[18][19]
No comments:
Post a Comment