In vivo anthelmintic effect of flavonol rhamnosides from Dryopteris crassirhizoma against Dactylogyrus intermedius in goldfish (Carassius auratus).

The purpose of the present study was to assess the anthelmintic property of plant-derived polyphenolic compounds extracted and isolated from Dryopteris crassirhizoma against Dactylogyrus intermedius in goldfish. The active ethyl acetate extract was loaded on an open silica gel column and eluted with chloroform-methanol. According to (1)H-nuclear magnetic resonance (NMR), (13)C-NMR, and mass spectral data, the structures of three purified compounds were identified as protocatechuic acid, sutchuenoside A, and kaempferitrin. Among these compounds, sutchuenoside A and kaempferitrin were observed to be effective with median effective concentration (EC50) of 3.01 and 2.71 mg L(-1), respectively. The alterations in the tegument of the parasites treated with isolated compound were examined using scanning electron microscopes. Ultrastructural micrographs revealed shrinkage of body surface, dense tegumental folds, and disheveled protuberances. The structural deformities in the treated parasites were indicative of an efficient anthelmintic activity of the isolated compound kaempferitrin. In addition, the 48-h median lethal concentration for sutchuenoside A and kaempferitrin against goldfish were 12.03- and 11.98-fold higher than corresponding EC50. The present results showed that ethyl acetate extract of D. crassirhizoma may be considered as a potent source, and sutchuenoside A and kaempferitrin as new natural parasitic agents against D. intermedius.