Unsaturated long-chain substances

All unsaturated long-chain substances (Ci2-Ci ) increase during prolonged fasting [18]. 

Insects make unsaturated as well as saturated hydrocarbons. The former as well as long-chain alcohols and their esters often form the volatile pheromones with which insects communicate. Thus, the female pink bollworm attracts a male with a sex pheromone consisting of a mixture of the cis,cis and cis,trans isomers of 7,11-hexadecadienyl acetate,13 and European corn borer males are attracted across the cornfields of Iowa by czs-ll-tetradecenyl acetate.14 Addition of a little of the trans isomer makes the latter sex attractant much more powerful. Since more than one species uses the same attractant, it is possible that the males can distinguish between different ratios of isomers or of mixtures of closely related substances. 

The quantity of bound flavouring substance also depends on the chain length of the fatty acids in the triglyceride, and on the presence of saturated or unsaturated fatty acids in it. Triglycerides with long chain fatty acids bind less ethanol and ethyl acetate than those with short chain fatty acids [6]. Triolein - a triglyceride that only contains the unsaturated oleic acid - binds more flavour than tripalmitin and trilaurin (both of which contain only saturated fatty acids) [6]. 

The isolation of the leukotrienes, the elucidation of the structures ofthese substances, and the fact that they are derived from long-chain poly-unsaturated fatty acids by a lipoxygenase pathway has added a new dimension to the research of eicosanoids. An account of the recent advances in the leukotriene field will be found in the latter part of this Chapter. 

Long-chain alkylphenols have been investigated extensively (33) by both adsorption and reversed-phase partition methods (34). The cashew phenols (from Anacardium occidentale) comprise cardanol (1), cardol (2), 2-methylcardol (3), and anacardic acid (4), each existing as a mixture of the saturated, 8 -monoene, 8 ,11 -diene, and 8 ,1 l ,14 -trieneconstituents. In ammoniated solvent [light petroleum-diethyl ether-ammonia (60 40 2)] the acidic compound anacardic acid remained practically on the baseline, whereas in an acidic solvent [light petroleum-diethyl ether-formic acid (70 30 1)] it migrated toward the solvent front as an intramolecularly bonded substance. In natural cashew nut shell liquid the phenols and their unsaturated constituents have the values 0.20 (cardol). 

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