Analysis of polyprenols by supercritical fluid chromatography

Applications of supercritical fluid chromatography (SFC) to the analysis of plant polyprenols are described. By the use of SFC, chromatographic resolution of polyprenol homologs and their geometric isomers was improved markedly as compared with that obtained by the use of conventional high-performance liquid chromatography (HPLC). Under optimized SFC conditions, individual homologs from 10 mer to 100 mer were separated. It was also possible to isolate each geometric isomer of polypernol homologs from 13 mer to 20 mer by the fractionation using SFC. The chain-length distributions of polyprenol samples determined by SFC agreed essentially with those determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). SFC analysis of polyprenols extracted from the leaf, root and seed coat of a rubber-producing plant, Eucommia ulmoides Oliver (E. ulmoides), has revealed the presence of all-trans polyprenols with degrees of polymerizations larger than 10, for the first time in nature. The all-trans polyprenols had broad distributions of chain-lengths leading to high molecular weight, which suggests that the polyprenols should act as biosynthesis intermediates for the high molecular weight trans-1,4-polyisoprene in this plant. The chain-length distributions of the trans polyprenols from the leaf, root and seed coat differed from each other, suggesting the presence of site-specific control mechanisms of chain-termination. On the other hand, cis polyprenols have been found to occur in all parts of E. ulmoides. They had narrow chain-length distributions similar to those of dolichols.