Structure and Distribution of Cerebroside Containing Unsaturated Hydroxy Fatty Acids in Plant Leaves

Abstract

The component monounsaturated 2-hydroxy fatty acids with carbon numbers of 22, 24, 25, and 26 in wheat leaf cerebroside were found to be Z-forms of the n-9 series. From liquid chromatography-mass spectrometry of the cerebroside, an exclusive combination of the unsaturated hydroxy fatty acids with 4-hydroxysphingenine was confirmed, one of the principal ceramide moieties being 2'-hydroxy-16'-Z-tetracosenoyl-4-hydroxy-8-sphingenine. The distribution of the unsaturated hydroxy fatty acids in the cerebrosides from the leaves of gramineous plants was analyzed. Cerebroside species having unsaturated hydroxy fatty acids were detected in the leaves of chilling-resistant rye and oats as well as wheat. These cerebroside species, however, were not detected in the leaves of chilling-sensitive plants such as rice and maize. The unsaturated hydroxy fatty acids were found only in 3 species of chilling-resistant plants (broccoli, chrysanthemum, and dandelion) among the 21 plant species analyzed. It was noteworthy that no species of chilling-sensitive plants analyzed included significant amounts of cerebroside species containing these fatty acids.