Chapter 5 - Carbocyclic Fatty Acids: Chemistry and Biological Properties

Abstract

Carbocyclic fatty acids are distributed across several plant orders, most notably the Malvales, which includes cotton and Sterculia seeds. In Litchi chinensis seed oil, dihydrosterculic acid accumulates to over 60% of total fatty acids. One of these fatty acids, malvalic acid, is present in cottonseed oil, one of our major sources of edible fats. The cyclopropene fatty acids have been indicated as the causative agent in the production of abnormalities among animals put on crude cottonseed oil diet. Because of the high reactivity of the cyclopropene ring, the purification and derivatization of the fatty acids that contain this functional group are difficult. Therefore, in studies of the structure and biosynthesis of these fatty acids, usage has been made of derived compounds, which have greater stability and other useful characteristics. Long-chain cyclopropane fatty acids (CPA-FAs) have also been described in various polar lipid classes in root, leaf, stem, and callus tissue in plants of the Malvaceae where they may function in resistance to fungal attack. The CPA-FAs are widely distributed in microorganisms, the seed oils of subtropical plants, protozoa, and less commonly, within fats and phospholipids produced by animals. Recently, CPA-FAs, lactobacillic acid and dihydrosterculic acid, have been detected in milk and dairy products from cows fed with corn silage. During the past few years, the presence of cyclopropane-containing fatty acids in human serum and adipose tissue has been demonstrated. This chapter describes the chemistry and biological properties of both cyclopropene and CPA-FAs.