Abstract: The plant chemotaxonomical marker of Fritillaria L. is discussed in this paper according to the information on chemical components. Plenty of evidence shows that 5α-cevanine isosteroidal alkaloids are the characteristic constituents of this genus. In the light of the biogensis of this kind of alkaloids, the C-13 and C- 17 of the molecular structures may be rational positions uniting a nitrogenous group in their biosyntheses which make two kinds of 5α-cevanine isosteroidal alkaloids, the dihydrogen of C- 13 and C- 17 being at the state of trans-configuration (e. g. verticine, verticinone) and at the state of cisconfiguration (e.g. delavine, chuanbeinone and songbeinine). Meanwhile, this paper reports the existence and content of some 5α-cevanine isosteroidal alkaloids in main Chinese fritillarias. This result reveals that there may be a relationship between the formation of characteristic constituents on one hand and other morphological characters and distribution of the plants concerned on the other,which encourages further investigation.

Key words: Liliaceae, Fritillaria L., Characteristic constituents, 5α-cevanine isosteroidal alkaloids