Mycetoindole, an N-acyl dehydrotryptophan with plant growth inhibitory activity from an actinomycete of the genus Actinomycetospora.

A rare actinomycetal strain of the genus Actinomycetospora was found to produce a new tryptophan derivative, designated mycetoindole (1). The structure of 1 was determined to be N-3-methylcrotonoyl (Z)-dehydrotryptophan by NMR and MS analytical methods. Compound 1 reduced the root growth of lettuce Lactuca sativa seedlings at concentrations above 0.1 μM and almost completely inhibited seed germination at 10 μM.