Biosyntheis of volatile C-13 norisoprenoid

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1.Damascenone progenitors in the flowers of Rosa damascena Mill.Two damascenone progenitors have been isolated from the flowers of R. damascena Mill. Their chemical structures were determined to be megastigma-6,7-dien-3,5,9-triol 9-Ο-β-D-glucolyranosides. The stereo chemistry for each compound was also determined by the direct comparison of their NMR spectra as well as chromatographic profiles on HIPLC.2.Damascenone progenitors in green te extractsDuring the course of sterilization of green tea extract for production of canned or bottled green tea drinks, damascenone was generated as off-flavor compound. The progenitors were isolated and identified to be acetylenic diol and allenic triol glucosides. Their stereo chemistries were also determined by comparison with synthetic specimens. We have also proposed the conversion routes for these compounds to damascenone.3.Carotenoid cleavage enzymes being involved in the formation of C13-norisoprenoidsC-13 Norisoprenoid volatile compounds are speculated to be generated from carotenoids such as β-caroten, neoxantin by the action of carotenoid cleavage enzymes in plant tissues, such as some fruits and flowers. We have, for the first time, characterized an enzyme from star fruit (Averrhoa carambola) and green tea leaves. Similar enzymes were characterized from animals and quince fruits by the group of Prof. Winterhlater. We have characterized not only the biochemical profiles, but also the products on the enzymatic reaction from b-carotene.