The occurrence of geometric polyprenol isomers in the rubber-producing plant, Eucommia ulmoides Oliver

The chain length and geometric isomerism of polyprenols from Eucommia ulmoi des Oliver were analyzed using supercritical fluid chromatography. After in tensive effort to establish separation conditions for geometric isomers, a phenyl-bonded silica gel-packed column was found that cleanly separated pol y-trans and -cis prenols. The presence of long-chain poly-trans prenols (> 9 mers) was confirmed for the first time in plants. Trans isomers were foun d in the leaf, seed coat, and root, but not in the bark and seed. Poly-tran s prenols in this plant may act as intermediates for trans-polyisoprene bio synthesis.