tolito
Forum Fanatic
Topics: 119
Posts: 2,164
|
can anyone make a list of these? i know only:
omega 3
linolenic acid
omega 6
linoleic acid
arachindonic acid
palmitic acid
thanks.
___________________
It has been a looooong hard journey but I am inches away from my destination...
|
| rouadefoc
Forum Senior
Topics: 4
Posts: 109
|
You are right, Linoleic acid and arachidonic acid are omega 6, linolenic acid is omega 6 and this are only acids of physiologic importance.
Palmitic acid is saturated so is not omega, becouse the double bond doesn t exist.
I m reading from lippincot s and don t find more.
___________________
When God is protecting who can stand against?May God be with all of us.
|
| rouadefoc
Forum Senior
Topics: 4
Posts: 109
|
N-6 FATTY ACIDS
* Linoleic acid (18:2 n-6) is the most common polyunsaturated fatty acids, in plants and animal tissues. The major sources for human food are soybean, sunflower, palm, canola, and cotton.
linoleic acid
It was isolated in 1844 by Sacc (Ann 1844, 51, 213), and after a long controversy its exact structure was clarified in 1939 (Hilditch TP et al., J Soc Chem Ind 1939, 58, 233) and it was synthesized only in 1950 (Raphael RA et al., Nature, 1950, 165, 235).
It cannot be synthesized by animals which must find it in plant foodstuff. It is said an essential fatty acid for animals. Walnut, peanut, seeds of sunflower, grape, corn, sesame and soya contain large amounts of that fatty acid. Linoleic acid is the precursor of all the (n-6) series formed by desaturation and elongation.
Two trans isomers of linoleic acid have been detected in seed oils. The 9c,12t isomer was found in Crepis rubra and the 9t,12t isomer was found in Chilopsis linearis.
* g-Linolenic (18:3 n-6) is the first intermediate formed and therapeutic properties have been claimed for it. This fatty acid was first noted in evening primrose in 1919 (Heiduschka A et al., Arch Pharm 1919, 257, 33) and its structure elucidated in 1927 (Eibner A et al., Chem Umshau 1927, 34, 312).
This fatty acid is available from some seed oils from several plant families. Thus, Boraginaceae with borage (Borago officinalis) (10-25%), Echium spp (5.5-11.7%), and Myosotis spp (4.4-20.2), Onagraceae with evening primerose (Oenothera biennis) (7-10%), Cannabaceae with Cannabis sativa (3-6%), Loasaceae with Nasa (3.5-10%), Caryophyllaceae with Minuartia laricifolia (15.6%), and Saxifragaceae with black currant (Ribes nigrum) 4-20% and Grossularia burejensis (12%) are the main groups which are sources of g-linolenic. A review on the distribution, properties, and extraction may be consulted for further information (Clough PM, Structured and modified lipids, Gunstone FD Ed, M Dekker, NY 2001, pp.75-117). A comprehensive review of 45 plant species that are potential sources of g-linolenic may be consulted (Guil-Guerrero JL et al., JAOCS 2001, 78, 677). Seeds from 50 species of Caryophyllaceae were also surveyed (Guil-Guerrero JL et al., JAOCS 2004, 81, 659).
There are reports of the development of a genetically modified rapeseed containing this fatty acid (Lassner M, Lipid Technol 1997, 9, 5).
In surveying the fatty acid composition of eukaryotic microorganisms, it was found that g-linolenic was present in lower fungi (Shaw R, Adv Lipid Res 1966, 4, 107). Several Mucor and Mortierella species are potential sources of g-linoleic (8-18% of neutral lipids). Attempts have been made to produce materials from these sources on a commercial basis. A detailed review on this topic may be consulted (Ratledge C, Structured and modified lipids, Gunstone FD Ed, M Dekker, NY 2001, p. 351).
* Dihomo-g-linolenic (20:3 n-6) : This fatty acid was found in small amounts (up to 5%) in some fungi such as Mortierella or Condiobolus. Higher levels (up to 18%) could be produced under particular fermentation conditions (Ratledge C, Structured and modified lipids, Gunstone FD Ed, M Dekker, NY 2001, p. 351).
* Arachidonic acid (20:4 n-6) is the most important of this series: it is a major constituent of membrane lipids (phospholipids) and is the principal precursor by enzymatic action of hormone-like compounds known as eicosanoids including the prostaglandins (prostanoids), isoprostanes, and isofurans.
trans-arachidonic acid
The detection and quantification of trans-arachidonic acids in vivo may be used as a specific index to assess the degree of cellular injury mediated by NO2 since these isomers were shown to be produced in human blood plasma (Zghibeh CM et al., Anal Biochem 2004, 332, 137).
An uncommon (n-6) fatty acid was discovered in retina, c14:2 (n-6), acylating a NH2 terminus of a retinal protein, recoverin, involved in the regulation of the photoreception mechanism (Dizhoor AM et al., J Biol Chem 1992, 267, 16033).
The 28:7n-6 fatty acid and other very long-chain polyunsaturated fatty acids had been found in fish oil, and these had probably been derived from the diet (Rezanka T, J Chromatogr 1990, 513, 344). The identification of 28:7n-6 in several marine marine dinoflagellates support that hypothesis (Mansour MP et al., Phytochemistry 1999, 50, 541).
___________________
When God is protecting who can stand against?May God be with all of us.
|
| rouadefoc
Forum Senior
Topics: 4
Posts: 109
|
N-3 FATTY ACIDS
* Linolenic acid (18:3 n-3) is found only in plants (it comes mainly from the oil obtained from Linus usitatissimum which is used in industry as drying oil, ink, or linoleum component).
linoleic acid
It was recognized as a separate fatty acid in 1987 (Hazura K, Monatsh 1887, 8, 158) and its structure was elucidated in 1909 (Erdmann E et al., Ber 1909, 42, 1334) while it was synthesized only forty years later (Raphael RA et al.,J Chem Soc 1950, 2100). Linolenic acid is the major fatty acid of plant leaves, stems and roots and is the precursor of the (n-3) series which is essential in fish and probably in other animals. The major sources for human food are soybean and canola.
* Stearidonic acid (18:4 n-3) is produced in vivo by desaturation of a-linolenic acid and is the precursor of EPA. The stearidonic acid supplementation was claimed to be beneficial in term of skin moisturization, thrombosis, inflammation, and cancer.
It is found widely in fish oil, but also in some vegetable oils, the most common source being black currant oil (2-4%). It was also detected in several Boraginaceae (leaves and seeds) at significant levels (4-19%), in Loasaceae (2-8.5%), in Saxifragaceae (Grossularia burejensis, 5.8%; Ribes spp, 0.9-4.4%) and in several Primula species (11-14%). Only Echium plantagineum has been selected as a commercial-scale source of stearidonic acid.
A review on this fatty acid may be consulted for further information (Clough PM, Structured and modified lipids, Gunstone FD Ed, M Dekker, NY 2001, pp.75-117)
Stearidonic acid occurs also in microorganisms a a minor component but was found at high level (8% of total lipids) in the phosphatidylcholine fraction of various mutants of Mortierella alpina (Jareonkitmongkol S et al., Appl Environ Microbiol 1992, 58, 2196).
Canola seeds have been genetically remodeled to accumulate stearidonic acid, thus facilitating increased compliance with the recommended dietary intake of n-3 fatty acids (Ursin VM, J Nutr 2003, 133, 4271).
* EPA (20:5 n-3) and/or DHA (22:6 n-3) are found in unicellular marine algae, brown macroalgae, in moss cells and in many animal tissues (mainly in nervous tissues). DHA is the most abundant fatty acid in the vertebrate brain. Several studies have shown that DHA is itself necessary to support optimal function of the brain and retina (Mitchell DC et al. Biochem Soc Trans 1998, 26, 365). They are important components of fish oil triacylglycerols and their health benefits are claimed to be diverse and orientated against many human disorders (see the site "Fats of Life"). It was also suggested that the evolution of the large human brain depended on a rich source of DHA from vegetal or animal food (Crawford MA et al., OCL 2004, 11, 30).
The need for a sustainable replacement for diminishing fish stocks as source of EPA has driven many efforts towards the search of its possible synthesis in transgenic plants (Sayanova OV et al., Phytochemistry 2004, 65, 147).
A brief review of the current and official acceptance of health benefits from long-chain n-3 fatty acids has been released by Ackman RG (Inform 2004, 15, 550). The putative mechanisms whereby marine n-3 fatty acids may modulate the carcinogenic process were examined in another review (Larsson SC et al., Am J Clin Nutr 2004, 79, 935).
A review of the structural roles of EPA and DHA in cellular membranes in bacteria as well as in multicellular organisms has been released by Valentine RC et al. (Prog Lipid Res 2004, 43, 383).
Seeds from Agathis robusta, an Australian primitive gymnosperm (Araucariaceae), were shown to contain small amounts of EPA (together with arachidonic acid), probably deriving from stearidonic acid (Wolff RL et al. Lipids 1999, 34, 1083).
EPA has been identified as a significant component in several fungal and algal oils but none of these has been exploited commercially.
The production of EPA and DHA by microorganisms (fungi, microalgae) has been extensively reviewed by Ratledge C (Structured and modified lipids, Gunstone FD Ed, M Dekker, NY 2001, p.351).
The Martek company has produced a single-cell oil containing about 40% of DHA from the heterotrophic microalga Crypthecodinium cohnii, this product being used in many food systems such as milk (Kyle DJ, Lipid Technol News 1997, 3, 100).
The production of EPA and DHA in transgenic plants which might lead to a sustained source of these fatty acids for use in human and animal food was reviewed by Domergue F et al. (Trends Plant Sci 2005, 10, 113).
An extensive review of the membrane properties of DHA may be consulted for further information (Stillwell W et al., Chem Phys Lipids 2003, 126, 1).
EPA contained in galactosyl diglycerides and phospholipids of marine diatoms was shown to be the source of a short-chain aldehyde, heptadienal (7:2 n-3), which participates to deleterious effects on zooplankton crustaceans (d'Hippolito G et al., Biochim Biophys Acta 2004, 1686, 100).
DHA was shown to be oxidized, as arachidonic acid, into isoprostane-like compounds (neuroprostanes) which seem to be of great value to appreciate oxidative injury to the neural tissues and to generate hydroxylated derivatives (docosatrienes) which are potent in preventing inflammation.
Two uncommon (n-3) fatty acids were described in cultures of fibroblasts, 14:3(n-3) and 16:4(n-3), as metabolites produced by normal conversion of 20:5(n-3) in peroxisomes (Williard DE et al., J Lipid Res 1998, 39, 978). 16:4(n-3) was also identified in the extract of the sponge Callyspongia sp found off the coast of New South Wales, Australia (Urban S et al., Lipids, 1997, 32, 675). An unusual n-3 polyunsaturated fatty acid, 18:5 n-3, was isolated from a raphidophyte alga, Heterosigma akashiwo (Bell MV et al., Phytochemistry, 1997, 45, 303). The high abundance of 18:5n-3 in some dinoflagellates, prasinophytes, haptophytes and raphidophytes (see Bell et al., 1997 for references) may be due to a chain-shortening mechanism from 20:5n-3 as demonstrated for 22:6n-3 formed by chain-shortening from 24:6n-3.
In some plants (spinach, tobacco, fresh-water algae), an uncommon trienoic fatty acid (7,10,13-hexadecatrienoic acid, 16:3 n-3) is found and was the base of a division of plants into the so-called "16:3-plants" (prokaryotic-like) and "18:3-plants". This fatty acid is mainly located in glycolipids of the chloroplast membranes. Along with some angiosperms, it was shown that the occurrence of 16:3 n-3 is characteristic of prokaryotic organisms such as cyanobacteria, as well as of microalgae, mosses, ferns, conifers, and other eucaryotic plant groups of a lower taxonomic position.
Very long chain (n-3) fatty acids were described in the blubber of seals (Phoca hispida) from northern fresh or seawater. Thus, 23:5, 24:3, 24:4, 24:5, 24:6, 26:5, 26:6 and 28:7 were found at a concentration not exceeding 0.2% (Kakela R et al., Lipids 1995, 30, 725). In Ophiuroidea (Brittle star) 24:6n-3 has been observed at concentrations of 3-15% in total fatty acids and particularly in some phospholipids (Takagi T et al., Lipids 1986, 21, 430; Kawasaki K et al., Fisheries Sci 2000, 66, 614).
The presence of the most unsaturated fatty acid (28:8 n-3) was detected in oil derived from the dinoflagellate Crypthecodinium cohnii. As 22:6 n-3, it contains the maximal number of methylene-interrupted double bonds in the fatty acid chain with also a -CH2-CH2- group at both ends of the molecule (Van Pelt CK et al., J Lipid Res 1999, 40, 1501). It was shown to be present also in another dinoflagellate Prorocentrum micans (Mansour MP et al., Phytochemistry 1999, 50, 541). Furthermore, this fatty acid was also detected in a sample of fish oil concentrate.
rule1.gif (1033 octets)
___________________
When God is protecting who can stand against?May God be with all of us.
|
| tolito
Forum Fanatic
Topics: 119
Posts: 2,164
|
thanks rouadefoc,
it is comforting to know that that is all we need to know!
___________________
It has been a looooong hard journey but I am inches away from my destination...
|
| rouadefoc
Forum Senior
Topics: 4
Posts: 109
|
I hope i wasn t too stuffy... anyway this are some of it.
___________________
When God is protecting who can stand against?May God be with all of us.
|
|
| |
| | | | | | |
