乳中共轭亚油酸异构体合成机制的研究进展

Research Progress in the Mechanism of the Biosynthesis of Conjugated Linoleic Acid Isomers in Milk

共轭亚油酸(conjugated linoleic acid,CLA)是一组十八碳共轭二烯酸的统称,具有多种重要的生理活性,其中c9,t11-CLA具有很强的抗癌作用,t10,c12-CLA具有减肥和防治Ⅱ型糖尿病的功能。在自然界,CLA主要存在于牛羊的乳中,通常包含c9,t11-CLA和t10,c12-CLA等异构体,但含量很低。牛羊瘤胃中的一些微生物参与了不同CLA异构体的生物合成。本文综述了CLA的结构和功能、CLA异构体分析方法、乳中CLA的组成、乳中CLA的合成途径、提高乳中CLA含量的方法和瘤胃中合成CLA的微生物的研究进展,为开展更深入的研究提供一些思路和参考。

Conjugated linoleic acid （CLA） is a collective term for geometric and positional isomers of linoleic acid with conjugated double bonds. They have been found to be responsible for many biological properties that are related to human health, c9,t11-CLA has anti-carcinogenic activity, and t10,c12-CLA seems to be specifically responsible for reducing body fat and enhancing energy metabolism. CLA occurs naturally in milk fat in a relatively low level. Several CLA isomers such as c9,t11-CLA and t10,c12-CLA are detected in milk. These CLA isomers are mainly biosynthesized by some bacteria in the rumen. The structure and functions of CLA, analytical methods for CLA isomers, the composition and biosynthesis pathways of CLA in milk, methods of enhancing CLA content in milk and microorganisms involved in the biosynthesis of CLA in the rumen are reviewed in this paper.