Antitrypanosomal Activity and Acute Toxicity of Euphorbia hirta Leaf Extract and a Green-Synthesized Vanadium-Based Nanoparticles against Trypanosoma brucei brucei in Mice

Abstract

African trypanosomiasis remains an important parasitic disease for which limitations associated with existing trypanocidal drugs necessitate alternative therapeutic approaches. This study evaluated the phytochemical composition, in vitro and in vivo antitrypanosomal activity, and acute toxicity of aqueous Euphorbia hirta leaf extract and green-synthesized vanadium nanoparticles against Trypanosoma brucei brucei in mice. Aqueous E. hirta leaf extract was subjected to phytochemical and GC–MS analyses and used for green synthesis of vanadium nanoparticles, which were characterized by FTIR and SEM. Acute toxicity was assessed using Lorke’s method. In vitro and in vivo antitrypanosomal activities were evaluated against T. brucei brucei, with parasitaemia, body weight, PCV, and histopathological changes assessed in infected mice. Phytochemical screening detected alkaloids, flavonoids, tannins, saponins, steroids, terpenoids, coumarins, carbohydrates, and proteins, while GC–MS identified 25 constituents. In vitro, both treatments inhibited parasite motility in a concentration- and time-dependent manner, with complete inhibition at 10 mg/mL. Acute toxicity testing indicated LD₅₀ values ≥ 3000mg/kg for the synthesized nanoparticles and ≥ 5000mg/kg for the leaf extract. In vivo, significant differences were observed among treatment groups for parasitaemia (H = 18.30, p = 0.006), body weight (H = 19.19, p = 0.004), and PCV (H = 16.09, p = 0.012). Histopathological examination showed reduced tissue alterations in treated mice compared with infected untreated controls. E. hirta extract and green-synthesized vanadium nanoparticles demonstrated preliminary parasite-suppressive activity but were less effective than diminazene aceturate. Further studies incorporating dose optimization, mechanistic investigations, pharmacokinetics, and long-term safety assessment are suggested.