Evaluation of anti-Toxoplasma effects of lipid nanoparticles carrying Tea tree oil on Toxoplasma gondii tachyzoites in Vero Cells

Toxoplasma gondii is a protozoan parasite that infects more than a third of the world's population. The drugs used today to treat toxoplasmosis cause severe side effects in many people and have poor success in treating chronic infections. In the current study, extracted oil from tea leaf was loaded into solid lipid nanoparticles (SLNs) and its anti- Toxoplasma properties were analyzed. Double emulsification technique was employed to provide SLNs and its physical criteria was calculated by transmission electron microscope (TEM) and dynamic light scattering (DLS). Cell toxicity and anti-intracellular Toxoplasma activity were investigated by a MTT assay. The anti- Toxoplasma activity of TTO-SLNs was evaluated by trypan-blue staining. The TTO-SLNs were round with a mean particle size of 85.23 nm and clear and stable margins. An association was seen between the cell toxicity of TTO-SLNs with the concentration of the component ( P -value = 0.009). The cytotoxic concentration (CC 50 ) against Toxoplasma was > 10 mg/mL, while it was concentration-dependent ( P -value < 0.0001). the viability of T. gondii - infected Vero cells was higher in lower concentrations of TTO-SLNs ( P -value = 0.0174), while at least 80% of T. gondii- infected Vero cells remained alive in the concentration ˃1 mg/mL. Overall, our findings demonstrated high anti- T. gondii properties of TTO-SLNs, suggesting the promising role of SLNs to carry TTO. In addition, our findings showed prolonged release of the TTO from SLNs capsulation of the can lead to, suggesting the capability of TTO-SLNs to be employed for chronic phase (cyst stages), which should be further investigated in animal models.