Differences in polyisoprenoid alcohols of mono‐and dicotyledonous seeds

Abstract

Abstract A lipid fraction enriched in polyisoprenoid alcohols was prepared from seeds of a number of crop plants, using Florisil chromatography. Analysis by HPLC of the fraction from soybeans showed a series of peaks corresponding to α‐saturated homologues (dolichols) from 15 to 22 isoprene units in length. Similar results were obtained with seeds of other dicotyledonous species (rapeseed, peanuts, mung beans, navy beans and peas). In contrast, analysis of the seeds of monocotyledonous plants (wheat, rye, barley, rice and corn) by HPLC gave split peaks, indicating the presence of nearly equal amounts of 2 different homologous series of compounds. The polyisoprenoid material isolated from wheat germ was subsequently shown to consist of a mixture of dolichols and α‐unsaturated homologues (polyprenols). Treatment with managanese dioxide selectively oxidized the polyprenols to the corresponding aldehydes, which were separated from the dolichols by TLC. The identity of the components was established by infrared‐nuclear magnetic resonance (IR‐NMR) spectroscopy and by comparison with authentic standards on high performance liquid chromatography (HPLC). The concentration of polyisoprenoid alcohols in seeds varied from 1–16 mg/100 g. Seeds of different species showed some differences in the pattern of homologues present.