Biosynthesis and enantioselectivity in the production of the lilac compounds in Actinidia arguta flowers

Monoterpenes Linalool 8-Hydroxylinalool 8-Oxolinalool Lilac aldehydes Lilac alcohols Lilac alcohol epoxides Deuterium labelling Enantioselective GC-MS Epoxide Isotope a b s t r a c t 0 - 2 H5)lilac aldehyde epoxide, rather than the lilac alcohols, was examined. Both substrates were non-enantioselectively con- verted to the lilac alcohol epoxides, suggesting two biosynthetic pathways for these compounds, contrary to previous reports. Their ability to process unnatural substrates indicates that A. arguta flowers have a greater biosynthetic capability than is suggested by their phytochemical composition. Linalool, the lilac compounds, and their biosynthetic intermediates were measured in the pistils, stamen, petals and sepals to determine if localisation in different organs contributed to only ( S)-linalool being processed to the lilac compounds. Both linalool enantiomers were present in all organs, while most (97%) of the lilac com- pounds, and their precursors, were found in the petals. ( S)-Linalool was not depleted from the flower pet- als, with respect to ( R)-linalool, during the time of maximum production of the metabolites of (S)- linalool.