Xanthumin and 8-epi-xanthatin as insect development inhibitors fromXanthium canadense Mill.

Summary Two insect development inhibitors againstDrosophila melanogaster have been isolated from the leaves ofX. canadense and identified as xanthumin and 8-epi-xanthatin.Search for Insect Development Inhibitors in Plants, IV. Part III, Heterocycles10, 117 (1978).This investigation was supported in part by grants (No. 056141 and No. 376065) from the Ministry of Education of Japan. The authors express their sincere thanks to Prof. Junkichi Iwasa of this department for his encouragement and to Dr Kenji Uneyama, Department of Industrial Chemistry of this University, for¹³C-NMR measurements.