Stable isotope labelling in biosynthetic studies of dill ether, using enantioselective multidimensional gas chromatography, online coupled with isotope ratio mass spectrometry

Abstract

(R/S)-Limonene and (+/−)-p-menth-1-en-9-ol as glucoside were synthesized as 13C-labelled stereosomers. Leaves of Anethum graveolens L. were fed with aqueous solutions of the labelled precursors. Feeding experiments and subsequent analysis of 13C/12C ratios were carried out by means of enantioselective multidimensional gas chromatography, online coupled with isotope ratio mass spectrometry. The dill plants were able to convert the fed menthenol-isomers into the corresponding dill ether stereoisomers. Nevertheless, it was proved that the stereospecific hydration of (R)-limonene leads to (4R, 8S)-p-menth-1-en-9-ol as the first step in dill ether biosynthesis. Based on these results, the biogenesis of dill ether in A. graveolens L. is discussed. Copyright © 2000 John Wiley & Sons, Ltd.