Study On The Fractionation And Physiological Function Of Congjugated Linoleic Acid Isomers

Congjugated linoleic acid (CLA) have been shown to have a varietyof biological activities to our health, in which c9, t11CLA andt10, c12CLA isomers are more important. Studies show that both isomershave different mechanisms, t10, c12CLA play a major role onanti-arteriosclerosis, immune enhancing properties, reduction in bodyfat accretion, muscle increasing and so on. c9, t11CLA play a major roleon promote growth and improve feed efficiency.It is necessary to separate these two isomers before develop theresearch on physiologic activity of CLA isomers. Although there are anumber of researches on the function of CLA, there is few study aboutthe influence of CLA on the survival of vascular endothelial cells.However, the survival of vascular endothelial cells has close relationshipwith the development of atherosclerosis. In this article three methodswere used such as: urea including, freeze crystallization and lipasefractionation of conjugated linoleic acid isomers. The present experimentwas to investigate the possible mechanisms on atherosclerosis in rats fedwith conjugated linoleic acid isomers. The detail study was as follows:the two isomers t10, c12CLA and c9, t11CLA were purificated withthe method of urea including. The results showed that when reaction wasfinished the purity of CLA was 93.68%, the ratio of t10, c12CLA/c9, t11CLA was 2.34:1. The purity of CLA in the urea crystal was 68.89%and the ratio of c9, t11CLA/t10, c12 CLA was 1.54:1.The technology of separation of Congjugated linoleic acid twoisomers by freezing crystallization was investigated. In this paper weused alcohol and removed impurity by refrigerating crystal in temperatureof-56℃. When the ratio of alcohol to CLA was 18:1, the freezing timewas 120h, we got the ratio of t10, c12CLA/c9, t11CLA was 16.07:1 in thecrystal, the yield was 5.4%. When the ratio of alcohol to CLA was 9:1, the freezing time was 31h, we got the ratio of c9, t11CLA/t10, c12CLAwas 1.63:1 in the fatty liquid, the yield was 82.6%. these prove thismethod can be used for obtaining high proportion of congjugated linoleicacid isomers production.LipaseAY30 fractionation of congjugated linoleic acid isomers wasoptimized by orthogonal test. At the optimal conditions t10, c12CLA /c9, t11CLA content in FFA was up to 2.63:1; and c9, t11CLA/t10, c12CLAcontent in ethyl ester was up to 4.72:1. Enzymatic fractionation ofcongjugated linoleic acid isomers was a very useful method.Novozym 435 was the best among 4 lipases when glyceride wassynthesized by esterification of glycerol and conjugated linoleicacid(CLA) in no-solvent system. The esterification ratio was 94.11%After using lipase 5 times the esterification ratio was also 87.28% withgyrating sieve. This lipase had a preference for the t10, c12CLA thanc9, t11CLA.CLA significantly increased the vascular endothelial cell number,vascular endothelial cells survival in a time- and dose-dependent mannerwhen concentration was less than 5μmol/L. Polyunsaturated FFA CLAcould partly prevent the cell death induced by PA and SA. At the end of8^th week after rat experiments, we carried out a detection of TC, TG, LDL,HDL, SOD, MDA. Compared with those in the hyperlipidemia moldelgroup, the levels of MDA, TC and TG in the serum of rats given CLAwere lower while the activity of SOD and HDL in the serum of rats givenCLA were increased. The CLA had an effect of slowing downatherosclerosis, the possible mechanism may be related to the decrease ofTG, TC, MDA and the increase of HDL, SOD and anti-peroxidation.