In vitro antiparasitic and synergic effects of camphene combined with pyrimethamine against Toxoplasma gondii

Currently, the standard therapeutic approach for the prevention and management of toxoplasmosis is the administration of chemical agents, which are associated with significant adverse side effects. Considering the elucidations presented and the biological properties of camphene (CP), the current research seeks to check the effects and the synergistic interactions of this natural monoterpene against Toxoplasma gondii. The anti-Toxoplsma and synergic effects of CP were examined against T. gondii tachyzoites and its intracellular forms. Furthermore, the impact of CP on the T lymphocytes- associated cytokines and DNA damage- related genes, as well as its effects on the plasma membrane and inducing apoptosis and the nitric oxide (NO) production, were evaluated. CP, principally in conjugation with pyrimethamine (PY), notably (p<0.001) dropped the tachyzoites viability, the intracellular forms, and the rate of infection in macrophages. The obtained FICI values of lower 0.5 for CP and PY indicate synergistic effects when CP is used in conjunction with PY. CP meaningfully upregulated tumor necrosis factor-alpha (TNF-a), interferon-gamma (IFN-g), and interleukin-12 (IL-12), and DNA damage-related genes, as well as NO releases in macrophage cells and the caspase-3 activity within the tachyzoites. The application of CP to tachyzoites displayed a dosage-dependent enhancement in plasma membrane permeability. The selectivity index values for CP, PY, and PY+CP exceeded 10, suggesting their safety for macrophages and specificity toward the parasite. We discovered that CP displayed promising in vitro antiparasitic properties against T. gondii. Additionally, the findings emphasized the potential of CP to eradicate tachyzoites through triggering apoptosis, NO production, and DNA damage, provoking cellular immunity cytokine, and increasing the plasma membrane permeability. Even so, advance evaluation is needed to clarify other mechanisms underlying its action and to evaluate its effectiveness in animal models and clinical trials.