Green-synthesis of MgO and ZrO2 nanocomposites: physicochemical properties and antiplasmodial activity in a mouse model

Malaria remains a significant global health burden, particularly in Sub-Saharan Africa, where drug resistance necessitates novel therapeutic strategies. This study evaluates the antiplasmodial potential of green-synthesized magnesium oxide (MgO) and zirconium oxide (ZrO2) nanoparticles and their composite (Mg/ZrO2) using Eucalyptus camaldulensis leaf extract. MgO, ZrO2, and MgO/ZrO2 nanoparticles were synthesized and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), revealing crystalline structures with particle sizes ranging from 39 to 60 nm. Acute toxicity assessment in mice indicated an LD50 > 2000 mg/kg bodyweight, confirming their safety. In vivo antiplasmodial activity was assessed using Plasmodium berghei-infected mice, with treatment groups receiving 50, 100, and 200 mg/kg bodyweight each of the nanoparticles. In the suppressive test, MgO-NPs, ZrO2-NPs, and MgO/ZrO2-NPs exhibited dose-dependent parasite inhibition of 66.79%, 34.72%, and 41.02% respectively at 200 mg/kg bodyweight. The curative test further confirmed parasite clearance, with MgO-NPs demonstrating the highest efficacy. Nanoparticle treatment also improved survival time and maintained body weight compared to untreated controls. The observed antiplasmodial effects is attributed to enhanced cellular uptake, reactive oxygen species (ROS) generation, and disruption of parasite metabolic pathways. These findings highlight the potential of MgO, ZrO₂ and MgO/ZrO2 nanocomposites as promising candidates for antimalarial drug development, warranting further mechanistic studies and preclinical validation.