In our study, extracts from dry roots rather than the aerial part were
used because roots have significantly higher alkaloid content (Dostál and Potáček, 1990).
We have demonstrated that the extracts with the highest contents of sanguinarine and
chelerythrine (D. lactucoides and S. canadensis) elicited the highest toxicity towards algae
and cyanobacteria. At the same time, the C. majus extract was also highly toxic to these
organisms, although its content of sanguinarine and chelerytrine was ~20 times lower than
in D. lactucoides and S. canadensis. Also, coptisine and magnoflorine were found in C.
majus extract in high concentrations (1.372 and 0.345% of dry root weight, respectively).
However, C. majus toxicity was apparently not caused by magnoflorine, because we
detected magnoflorine in D. lactucoides (and not in S. canadensis), while toxicity of S.
canadensis and D. lactucoides was similar. On the other hand, coptisine could be one of the
toxic components of S. lasiocarpum and C. majus extracts, which were relatively toxic to
cyanobacteria and algae in spite of the lower content of QBA.