In vitro efficacy of the essential oil of Piper cubeba L. (Piperaceae) against Schistosoma mansoni.

In this paper, cercariae, schistosomula, and adult Schistosoma mansoni worms were incubated in vitro with the essential oil of Piper cubeba (PC-EO) at concentrations from 12.5 to 200 μg/mL, and the viability was evaluated using an inverted microscopy. The effects of PC-EO at 100 and 200 μg/mL on the stages of S. mansoni were similar to those of the positive control (PZQ at 12.5 μg/mL), with total absence of mobility after 120 h. However, at concentrations from 12.5 to 50 μg/mL, PC-EO caused a reduction in the viability of cercariae and schistosomula when compared with the negative control groups (RPMI 1640 or dechlorinated water) or (RPMI 1640 + 0.1% DMSO or dechlorinated water + 0.1% DMSO). On the other hand, adult S. mansoni worms remained normally active when incubated with PC-EO at concentrations of 12.5 and 25 μg/mL, and their viabilities were similar to those of the negative control groups. In addition, at concentrations ranging from 50 to 200 μg/mL, separation of all the coupled adult worms was observed after 24 h of incubation, which is related to the fact of the reduction in egg production at this concentration. The main chemical constituents of PC-EO were identified by gas chromatography-mass spectrometry as being sabinene (19.99%), eucalyptol (11.87%), 4-terpineol (6.36%), β-pinene (5.81%), camphor (5.61%), and δ-3-carene (5.34%). The cytotoxicity of the PC-EO was determined, and a significant cytotoxicity was only obtained in the concentration of 200 μg/mL after 24 h treatment. The results suggest that PC-EO possesses an effect against cercariae, schistosomula, and adult worms of the S. mansoni.