Abstract: We report the results of biosynthetic studies on the sulfur-containing indole phytoalexins, antimicrobial compounds produced by plants after exposure to microorganisms. Feeding experiments with UV-irradiated sliced turnip root (Brassica campestris ssp. rapa) revealed that spirobrassinin (3) is formed via brassinin (la) and that la is biosynthesized by the intramolecular rearrangement of L-tryptophan to form unstable ...
