Ailanthus altissima has been known to be allelopathic plant since no plant can grow under the tree. Heisey et al (1990) showed that crude extracts of root and stem bark of A. altissima exhibited strong herbicidal activity. We confirmed plant growth inhibitors against Lactuca sativa in the aqueous extract of A. altissima bark. The compound was isolated and identified to be ailanthone known as quassinoid or allelopathic substance. Here, we report plant growth activities of ailanthone against Lactuca sativa, Pariucam crus-galli, Raphanus sativa L. and Daucus cavota L. in detail.
