Koninginin A: A Novel Plant Growth Regulator from Trichoderma koningii

Trichoderma koningii, isolated from the roots and soil line of an ornamental Diffenbachia sp., yielded, when cultured on shredded wheat, a novel metabolite trivially named koninginin A. The compound is a ketal that weakly inhibits the growth of etiolated wheat coleoptiles at 10-3 m, and is a white, finely crystalline compound with the molecular formula of C16H28O4 and a melting point of 80 ~ 84°C. The structure has been established by UV, IR, 1H NMR, 13C NMR, and MS.