Schistosomiasis remains a major neglected tropical disease, affecting approximately 600 million individuals worldwide and accounting for nearly 500,000 deaths annually. The principal causative species—Schistosoma haematobium, S. mansoni, and S. japonicum—drive significant morbidity through hepatomegaly, splenomegaly, and progressive hepatic fibrosis. Praziquantel (PZQ) remains the cornerstone of treatment; however, its limited efficacy against immature worms and eggs, combined with concerns over emerging drug resistance, underscores the urgent need for novel therapeutic alternatives. This study investigated the anti-schistosomal potential of green-synthesized zinc oxide (ZnO) nanoparticles (NPs) in a murine model of S. mansoni infection, benchmarked against PZQ. ZnO NPs were fabricated using ginger extract via an eco-friendly green synthesis approach. Fifty male BALB/c mice were randomly assigned to five groups (n=10): normal control, infected untreated control, infected treated with PZQ alone, infected treated with ZnO NPs alone, and infected treated with a PZQ–ZnO NP combination. Parasitological, histopathological, and fibrosis assessments were subsequently performed. All treatment groups demonstrated significant reductions in worm burden and tissue egg counts relative to infected untreated controls. Histopathological examination of untreated infected mice revealed extensive chronic granulomatous inflammation, concentric perioval fibrosis, fibroblast proliferation, hepatocellular necrosis, hydropic degeneration, marked collagen deposition, and portal-to-portal fibrous bridging. Treated groups, by contrast, exhibited marked hepatic improvement characterized by reduced granuloma size, diminished fibrosis, and decreased collagen deposition. Collectively, these findings indicate that green-synthesized ZnO NPs possess promising anti-schistosomal and antifibrotic properties, warranting further investigation as a potential adjunct or alternative therapeutic strategy for schistosomiasis management.

Entamoeba histolytica is an enteric tissue-invasive protozoan parasite causing amoebic colitis and liver abscesses in humans. Amoebic contact with host cells activates intracellular signaling pathways that lead to host cell death via generation of caspase-3, calpain, Ca²⁺ elevation, and reactive oxygen species (ROS). We previously reported that various NADPH oxidases (NOXs) are responsible for ROS-dependent death of various host cells induced by amoeba. In the present study, we investigated the specific NOX isoform involved in ROS-dependent death of hepatocytes induced by amoebas. Co-incubation of hepatoma HepG2 cells with live amoebic trophozoites resulted in remarkably increased DNA fragmentation compared to cells incubated with medium alone. HepG2 cells that adhered to amoebic trophozoites showed strong dichlorodihydrofluorescein diacetate (DCF-DA) fluorescence, suggesting intracellular ROS accumulation within host cells stimulated by amoebic trophozoites. Pretreatment of HepG2 cells with the general NOX inhibitor DPI or NOX2-specific inhibitor GSK 2795039 reduced Entamoeba-induced ROS generation. Similarly, Entamoeba-induced LDH release from HepG2 cells was effectively inhibited by pretreatment with DPI or GSK 2795039. In NOX2-silenced HepG2 cells, Entamoeba-induced LDH release was also significantly inhibited compared with controls. Taken together, the results support an important role of NOX2-derived ROS in hepatocyte death induced by E. histolytica.