Flavonoids of the primitive liverwort Takakia and their taxonomic and phylogenetic significance

The flavonoid chemistry of Takakia is described for the first time. T. lepidozioides, thought to be amongst the most primitive of extant liverworts, contains a high level and wide variety of flavone C- and O-glycosides, many of which are unique. New flavonoids include the 8-O-glucuronide and 8-O-xylosylglucoside of takakin (8-hydroxyacacetin), luteolin 6-C-arabinoside-8-C-pentoside, kaempferol 3-O-glucoside-7-O-xyloside and a number of tricetin C-glycosides.

The only other known Takakia species, T. ceratophylla, contains the same 4 major constituents but significantly lacks flavonols. The often suggested relationship of Takakia with the order Calobryales is not supported by the available flavonoid data. Biochemical affinities of Takakia with all major liverwort orders are noted and the flavonoid data are interpreted as supporting the concept of Takakia as an isolated branch among the ancestors of modern bryophytes.