SESQUITERPENE LACTONES OF CONOCEPHALUM-CONICUM

Investigation of the plant growth inhibitory activity of the extract of the liverwort, Conocephalum conicum afforded five sesquiterpene lactones, tulipinolide, zaluzanin C, zaluzanin D, 8α-acetoxyzaluzanin C and 8α-acetoxy-zaluzanin D. The latter two compounds are reported for the first time. Tulipinolide is responsible for the characteristic pungency of the female gametophyte of C. conicum. The guaianolides showed inhibitory activity toward the germination and growth of roots of rice in the husk. The male gametophyte of C. conicum indicated no pungency, showing the lack of tulipinolide. © 1979.