17 罹病食用ユリの産生する抗菌活性物質(口頭発表の部)

抄録

Bulbs of the lily Lilium maximowiczii (Japanese name: Yurine) have been used in Japanese dishes. Basal rot caused by Fusarium oxysporum has been a serious disease of Lilium maximowiczii. Ethyl acetate extract obtained from the diseased lily bulbs was separated by repeated chromatography, guided by TLC bioassay, to give two types of antifungal compounds: yurinelide (1) and chlorine-containing compounds (6 to 12). The first lily phytoalexin yurinelide was also induced in UV-irradiated or Fusarium oxysporum-inoculated bulb scales. Its unique 3-benzylidene-1, 4- benzodioxin-2(3H)-one structure was elucidated on the basis of HMBC, HMQC, and NOE experiments, as well as methanolysis products of 1. The structures of chlorine-containing compounds were elucidated as chlorinated orcinol derivatives from spectral data and synthetic studies. Timecourse study of these compounds in UV-irradiated lily scales indicated that these are produced in the plant tissue under stressed conditions. Increase of chloroperoxidase activity in UV-irradiated tissue suggested that these organochlorine compounds are synthesized by chlorination of non-chlorinous precursors with Cl^- and stress-induced H_2O_2 and chloroperoxidase.