Cephaeline formation

The effects of lAA, NAA and 2,4-D on the growth and alkaloid yields of root cultures in MS liquid medium are shown in Fig. (31). The cultured roots produced much more cephaeline than emetine, although the rootlets of the parental plant cultivated in a greenhouse contained almost the same amounts of emetine and cephaeline, i.e. 1.6% and 1.9% dry weight, respectively (Table 4). The roots grew well in a liquid medium in the presence of 5 mg/1 NAA, while the roots formed calli and swelled in the presence of 10 mg/1 lAA, and NAA and 0.5 mg/1 2,4-D and were not suitable for the alkaloid formation. Therefore, organized structures such as roots may be important for the biosynthesis of emetine and cephaeline. 

However, biosynthetic enzymes, which catalyze these reactions, have not been purified. Therefore, further studies are required to elucidate the effect of light on the formation and accumulation of the alkaloids. The contents of protoemetine, which have been regarded as the biosynthetic precursor of cephaeline and emetine, were extremely low irrespective of the different culture conditions. 

In the meantime, the formation of the main alkaloids in C. ipecacuanha under a variety of conditions has been extensively investigated emetine (1) in callus cultures (49) and under the effects of L-tyrosine supplementation (5t)) emetine (1) and cephaeline (2) in Panamanian ipecac (57), in Nicaraguan ipecac (52), in regenerates obtained by clonal propagation (53,54), in tissue cultures (55) and under the effects of exogenous feeding of shikimic acid and L-phenylalanine (55), in cell suspension and excised root cultures (57), in adventitious root cultures (58), and in callus cultures (56,59) and the effects of age and electrokinetic potential (60) ipecoside (7) in the roots (61) and the effect oi Azotobacter, leaf mold, and farmyard manure on alkaloid content (62). In addition, micropropagation systems for C. ipecacuanha have been developed (63-65). 

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