The analysis, characterization and the chemical syntheses of C(20) and C(22) cyclic fatty acid monomers formed in heated fish oi

Cyclic fatty acid monomers (CFAMs) are formed during heat treatment of fats and oils and represent a complex mixture of structural, geometrical and positional isomers. These compounds have been found responsible for inhibition of normal fat metabolism, liver enlargement and other histopathological changes, all of which have been confirmed through experimentation with laboratory animals.;Fish oil containing 18% eicosapentaenoic acid and 12% docosahexaenoic acid was heated at 275$spcirc$C for 12 hours. The heated fish oils was converted to methyl esters and hydrogenated using platinum oxide catalyst and 3-4 bars hydrogen gas. This hydrogenated sample was then urea fractionated. The hydrogenated non-urea fractionation was used to collect fractions of C$sb{20}$ and C$sb{22}$ CFAMs by HPLC on a C$sb{18}$ reverse phase column. The fractions collected by HPLC were then analyzed by gas chromatography-mass spectrometry.;Chemical synthesis of C$sb{20}$ and C$sb{22}$ CFAMs was carried out to enable (1) the determination of their physical and chemical properties, (2) to provide standards for the identification and characterization of CFAMs present in heated fish oils and (3) to make available pure standards for use in biological studies. Cyclopentyl and cyclohexyl CFAMs were synthesized to enable the identification of different cyclic fatty acids formed from both eicosapentaenoic and docosahexaenoic acids, C$sb{20}$ and C$sb{22}$ CFAMs respectively. Synthetic routes were developed to maximize the yield of both the intermediates and final products. Optimization of the chemical synthesis was carried out using the response surface methodology. Gas chromatography-mass spectrometry, high resolution $sp1$H nuclear magnetic resonance and fourier transform infra-red spectrometry were used for structural verification of intermediates and final products.