Unveiling Therapeutic Effects of Thymbra spicata L. on Cystic Echinococcosis

Background: The hydatid cyst (cystic echinococcosis) is the larval stage of Echinococcusgranulosus sensu lato, which accounts for significant zoonotic infections worldwide. Objectives: This study aimed to evaluate the in vitro and in vivo efficacy of the essential oil derived from Thymbra spicata L. (TSEO) against protoscoleces (PSCs) and hydatid cysts of E. granulosus. Methods: The components of TSEO were characterized using gas chromatography-mass spectrometry (GC-MS). The in vitro effects of TSEO on PSCs were determined using the eosin exclusion test. The effect of TSEO on caspase-3 gene expression and exterior ultrastructure of PSCs was investigated using real-time PCR and scanning electron microscopy (SEM), respectively. In vivo effects of TSEO at doses of 20, 30, and 40 mg/kg/day were also studied in mice with hydatid cysts. Results: Gas chromatography-mass spectrometry analysis showed that the main compounds in TSEO were carvacrol (65.88%), γ-terpinene (9.71%), and p-cymene (7.82%), respectively. The results showed the highest lethality of TSEO at 30 µg/mL after 60 minutes of exposure. The IC50 value was 18.60 µg/mL after 60 minutes of exposure to TSEO. After exposing PSCs to TSEO, the expression level of the caspase-3 gene increased over time with increasing concentration (P < 0.05). Scanning electron microscopy images of the cyst treated with 50 µL/mL of TSEO showed ultrastructural damage, rostellar disorganization, alterations in the teguments, and deformation of the cyst structure. In the in vivo assay, it was found that the average number, size, and weight of hydatid cysts decreased significantly (P < 0.05) after treatment with TSEO. The maximum efficacy was observed after treatment with TSEO at a dose of 40 mg/kg, resulting in a significant decrease in the number, weight, and size of hydatid cysts by 9.6 ± 1.51, 2.64 ± 0.39 g, and 0.18 ± 0.022 mm, respectively. Conclusions: The study findings confirmed the promising in vitro and in vivo effects of TSEO against hydatid cyst infection. Considering the possible mechanisms, TSEO provoked cell wall damage and induced apoptosis. However, more studies are needed to confirm these findings and clarify the precise mechanisms of action.