Isolation of bioactive components from Chelidonium majus L. with activity against Trichodina sp.

Trichodinids are the most common ciliates parasite present on the skin of pond-reared fish and can cause severe economic losses in aquaculture and ornamental fish breeding. The present study aims to evaluate the antiparasitic activity of the active components from Chelidonium majus L. against Trichodina sp. Bioassay-guided fractionation and isolation of the compounds with antiparasitic activity were performed on the ethanolic extract of C. majus yielding three bioactive alkaloids namely: chelidonine (1), chelerythrine (2) and sanguinarine (3). Results from in vivo antiparasitic assays revealed that these compounds when isolated could be 100% effective for the elimination of Trichodina sp. at the concentrations of 1.0, 0.8, and 0.7 mg L− 1, with the median effective concentration (EC50) values of 0.6, 0.33, and 0.32 mg L− 1, respectively. Furthermore, the promising chelidonine, chelerythrine and sanguinarine were subjected to acute toxicity tests for the evaluation of their safety to the host (Parabramis pekinensis). It was found that the 48 h median lethal concentration (48 h-LC50) values determined by the acute toxicity tests on P. pekinensis were 2.5, 3.8 and 1.5 mg L− 1 respectively. These results provided evidence that the isolated compounds, especially chelerythrine, can be exploited as novel antiparasitic agents for the control of Trichodina sp.