INDOLE PHYTOALEXINS FROM THE KOHLRABI (BR ASSICA-OLERACEA VAR GONGYLODES)

UV-irradiation of sliced stem tubers of kohlrabi (Brassica oleracea va r. gonglyodes) followed by incubation for 4 days, resulted in the prod uction of two new sulphur-containing indole phytoalexins, cyclobrassin one and 1-methoxyspirobrassinin, whose structures were elucidated on t he basis of spectroscopic data. Three known indole phytoalexins, spiro brassinin, methoxybrassitin and methoxybrassinin, and several minor ph ytoalexin-like compounds not yet identified were also isolated. The ac cumulation of these indole phytoalexins was also induced by abiotic el icitation with CuCl2. Feeding both of L-[beta-C-14]tryptophan and L-[( CH3)-C-14]methionine to UV-irradiated stem tuber tissue of kohlrabi in dicated that the S-containing indole phytoalexins were biosynthesized from these amino acids.