Ailanthone
Ailanthone is a quassinoid allelochemical produced by the tree Ailanthus altissima. It is a key agent behind the tree's strong allelopathic effects, which inhibit the growth of competing plants by suppressing seed germination and disrupting root elongation. Native to China, Ailanthus altissima has become one of the worst invasive species in North America and Europe, where ailanthone is known to contribute significantly to its competitive spread.