Triglycerides hydroxy acids

A number of closely related linear allenes have also been isolated from seed oils (Scheme 18.8). Examples are laballenic acid (18) [27], lamenallenic acid (19) [28] and phlomic acid (20) [29]. The hydroxy acid 21 was isolated as part of a triglyceride from the Chinese tallow tree Sapium sebiferum [30] and as its methyl ester 22 from the related species Sapium japonicum [31], which is found in Japan. 

Castor oil [CO Structure (4.3)] is a triglyceride of ricinoleic (12-hydroxyoleic) acid about 90% of the fatty acid portion of the molecule consists of ricinoleic acid and 10% in the form of non-hydroxy acids consisting largely of oleic and linoleic acids. Small amounts of stearic and dihydroxystearic acids are also found in some industrial grades. 

The carboxylic acids can be subdivided into nonvolatile fatty acids, volatile fatty acids, hydroxy acids, dicarboxylic acids, and aromatic acids (Fig. 3). The nonvolatile fatty acids are molecules with more than five carbon atoms, such as stearic and palmitic acids, which are the degradation products of fats and triglycerides. Three different 18-C fatty acids that are important constituents of plants include oleic and linoleic acids that are abundant in plant seeds, and linolenic acid, which is abundant in plant leaves. Volatile fatty acids are short-chain molecules with one to five carbon atoms, such as acetic and valeric acid, associated with anaerobic metabolism. The hydroxy-acids are common intermediates in biochemical pathways, including the tricarboxylic acid cycle. The excretion of hydroxyacids by algae, such as the... 

Ozonolysis of triglycerides is another useful reaction that can produce interesting monomers. An example of oxidative scission is given in Scheme 2.9, when applied to castor oil in a sequence of modifications leading to polyols and hydroxy acids. 

Vegetable Oils. Triglycerides form the principal component of most edible oils obtained from seeds and fruits small amoimts of free fatty acids and sterols occur also. As shown in Fig. 130, i, olive oil, a typical example, can be easily separated by adsorption TLC into these three fractions. Oils containing triglycerides of epoxy- and hydroxy-acids as well as those of the ordinary fatty acids show very characteristic... 

Reversed phase partition TLC may be applied to fractionate alcohols [78, 86], aldehydes and ketones [10, 125], fatty acids [4, 80, 84, 124] and their methyl esters [114, 213], keto-acids, hydroxy-acids and lactones [82]. More complete separations of these compounds or of suitable derivatives, are, however, obtained with gas chromatography and it is appreciably more sensitive than TLC it is moreover more suitable for quantitative determinations. Reversed phase partition TLC offers substantial advantages only in the analysis of lipids of relatively high molecular weight, like wax esters [86], steryl esters [79] (see also Chapter L), carotenoid esters (see Chapter K) and triglycerides [4, 81, 89, 124] some derivatives of naturally occurring lipids are also best fractionated on hydrophobic layers [21, 130, 131, 165]. 

Lipids also influence the properties of starch. Like free amino acids, monoglycerides or fatty acid esters of hydroxy acids, lipids form inclusion compounds with amylose (cf. 4.4.4.14.3). Like di- and triglycerides, they also reduce the swelling capacity and solubility by inhibiting water diffusion. Therefore, both degreasing as well as lipid addition are of importance as physical modification methods of starches. 

Sulfated Natural Oils and Fats. Sulfated natural triglycerides were the first nonsoap commercial surfactants introduced in the middle of the nineteenth century. Since then sulfates of many vegetable, animal, and fish oils have been investigated (see also Fats AND FATTY oils). With its hydroxyl group and a double bond, ricinoleic acid (12-hydroxy-9,10-octadecenoic acid) is an oil constituent particularly suited for sulfation. Its sulfate is known as turkey-red oil. Oleic acid is also suited for sulfation. Esters of these acids can be sulfated with a minimum of hydrolysis of the glyceride group. Polyunsaturated acids, with several double bonds, lead to dark-colored sulfation products. The reaction with sulfuric acid proceeds through either the hydroxyl or the double bond. The sulfuric acid half ester thus formed is neutralized with caustic soda ... 

Specialty waxes include polar waxes for more polar adhesive systems. Examples would be castor wax (triglyceride of 12-hydroxy stearic acid) or Paracin wax N- 2 hydroxy ethyl)-12-hydroxy stearamide) which are used in polyester, polyamide, or with high VA EVA copolymer-based systems. Other common polar waxes are maleated polyethylenes, which are used to improve the specific adhesion of polyethylene-based adhesives, and low molecular weight ethylene copolymers with vinyl acetate or acrylic acid, which are used to improve low temperature adhesion. High melting point isotactic polypropylene wax (7 155°C) and highly refined paraffin wax (7,n 83°C) are used where maximum heat resistance is critical. Needless to say, these specialty waxes also command a premium price, ranging from 2 to 5 times that of conventional paraffin wax. 

FIGURE 9. Endogenous lipoprotein metabolism. In liver cells, cholesterol and triglycerides are packaged into VLDL particles and exported into blood where VLDL is converted to IDL. Intermediate-density lipoprotein can be either cleared by hepatic LDL receptors or further metabolized to LDL. LDL can be cleared by hepatic LDL receptors or can enter the arterial wall, contributing to atherosclerosis. Acetyl CoA, acetyl coenzyme A Apo, apolipoprotein C, cholesterol CE, cholesterol ester FA, fatty acid HL, hepatic lipase HMG CoA, 3-hydroxy-3-methyglutaryl coenzyme A IDL, intermediate-density lipoprotein LCAT, lecithin-cholesterol acyltransferase LDL, low-density lipoprotein LPL, lipoprotein lipase VLDL, very low-density lipoprotein. 

Pullen, D.L., Palmquist, D.L., Emery, R.S. 1989. Effect of days of lactation and methionine hydroxy analog on incorporation of plasma fatty acids into plasma triglycerides.. / Dairy Sci. 72, 49-58. 

The major enzymes involved in lipoprotein regulation are (Ij acyl-CoAxholesterol acyl-transferase (ACAT), which esterifies some cholesterol in the core of chylomicrons (2) lec-ithin cholesterol acyltransferase (LCAT), which esterifies cholesterol and helps transfer it to LDL (3) lipoprotein lipase (LPL), which hydrolyzes triglycerides to free fatty acids (FFA) and glycerol and (4) 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which is essential in the synthesis of cholesterol and other steroids in the liver. 

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