This study aimed to evaluate the in vitro activity of the essential oil of Pinus nigra subsp. pallasiana against protoscoleces of Echinococcus granulosus sensu lato. In traditional Turkish folk medicine, the essential oils and resin of P. nigra and P. sylvestris are used externally for wound healing. They are also used in cattle for treating worms and as boiling essence against cold and stomachache. Protoscoleces were aseptically aspirated from sheep livers having hydatid cysts.Three concentrations (10, 30, and 50 mg/mL) of the essential oil from P. nigra subsp. pallasiana cones were used for 10-60 min. The essential oil was applied to protoscoleces of hydatid cyst to determine the scolicidal activity of the essential oil. Viability of protoscoleces was observed by 0.1% eosin staining.The rate of dead protoscoleces was found to be 2.27% in the control group, which was not treated with essential oil. The rate of dead protoscoleces increased to 61.69%, 69.39%, 75.98% and 71.76% respectively after, 10, 20, 30, and 60 min when the protoscoleces were exposed to the P. nigra subsp. pallasiana essential oil at 10 mg/mL concentration. When protoscoleces were exposed to the essential oil of P. nigra subsp. pallasiana for 10, 20, 30, and 60 min at 30 mg/mL concentration, the mortality rates of protoscoleces were determined as 3.82%, 91.33%, 94.67% and 96.74%, respectively. The mortality rate of 100% was determined at 50 mg/mL concentration after 60 min of exposure. According to statistical analysis, P. nigra subsp. pallasiana essential oil at all concentrations had significant scolicidal effects compared to the control group at all exposure times.The essential oil of P. nigra subsp. pallasiana needles showed scolicidal activity and it could be a new scolicidal agent for using in hydatid cyst treatment.
