In Vitro Evaluation of Schistosomicidal Activity of Essential Oil of Mentha x villosa and Some of Its Chemical Constituents in Adult Worms of Schistosoma mansoni

This study aimed to determine the composition of the essential oil of Mentha x villosa and to evaluate its biological effects in vitro on adult worms of S. mansoni. Rotundifolone (70.96 %), limonene (8.75 %), trans-caryophyllene (1.46 %), and β-pinene (0.81 %) were shown to be the major constituents of this oil. Adult worms of S. mansoni were incubated with different concentrations of the essential oil (1, 10, 100, 250, 500, and 1000 µg/mL) and of its constituents rotundifolone (0.7, 3.54, 7.09, 70.96, 177.4, 354.8, and 700.96 µg/mL), limonene (43.75 µg/mL), trans-caryophyllene (7.3 µg/mL), and β-pinene (4.03 µg/mL). No schistosomicidal activity was identified at the trans-caryophyllene and β-pinene concentrations studied. However, use of the essential oil (10 µg/mL), rotundifolone (7.09 µg/mL), and limonene (43.75 µg/mL) resulted in decreased worm motility continuing until 96 hours of observation. At higher concentrations (100 and 70.96 µg/mL, respectively), both the essential oil and rotundifolone caused mortality among adult worms of S. mansoni. The positive control praziquantel caused the death of all parasites after 24 h of evaluation. The results from this study suggest that the essential oil of Mentha x villosa presents schistosomicidal efficacy.