Identification of Sesquiterpene Lactones in the Bryophyta (Mosses) Takakia: Takakia Species are Closely Related Chemically to the Marchantiophyta (Liverworts)

摘要

Takakia lepidozioides has been considered to be the most primitive liverwort morphologically and classified initially in the Marchantiophyta (liverworts). However, the Takakia have been reclassified from liverworts to mosses on the basis of the similarity of the male sporophyte of T. ceratophylla to that of some mosses. Reinvestigation of secondary metabolites of fresh T. lepidozioides resulted in identification of eudesmane-type sesquiterpene lactones and hydrocarbon that are significant chemical markers of several liverworts. T. lepidozioides also produces a small amount of hop-22(29)-ene, together with coumarin, which produce the characteristic odor of T lepidozioides, and 1,4-hydroquinone; these are the predominant volatile components, whereas dihydrocoumarin, 1,4-benzoquinone, dihydrobenzofuran, a-asarone and a-tocopherol are minor components. These chemical results indicated that T. lepidozioides is more closely related to the Marchantiophyta than the Bryophyta. T lepidozioides is morphologically similar to the liverwort Haplomitrium species. However, both species are totally different chemically.