Nitrofuran (E)-N’-((5-nitrofuran-2-yl)methylene)furan-2-carbohydrazide: drug candidate for the treatment of visceral toxocariasis

Human toxocariasis is a globally neglected parasitic disease, commonly treated with benzimidazole anthelmintics. However, their efficacy is considered unsatisfactory, requiring the research and development of new drugs. Studies have shown that hetero-cyclic compounds with nitrogenous molecules are known for their properties of inducing oxidative stress on pathogens. This study aimed to evaluate the efficacy of the (E)-N’-benzylidenefuran-2-carbohydrazide (PFUR) and ten derivatives against Toxocara canis in preclinical tests. The compounds were tested in vitro, in duplicate, at a concentration of 1.0 mg/mL to 0.062 mg/mL in a microplate containing 100 Toxocara canis larvae in RPMI-1640 medium. The compound PFUR 2 showed activity against 100% of the larvae at the minimum larvicidal concentration (MLC) of 0.25 mg/mL and was selected for the subsequent tests. Furthermore, this compound also demonstrated non-cytotoxicity to murine macrophages and an adequate estimate of oral bioavailability, as determined by the “rule of five” in computational models. After, two in vivo tests were conducted on Swiss mice. In the groups treated with PFUR 2 (10 mg/kg/5 d, IG), 10 days and 30 days after inoculation with 500 T. canis eggs, there was a reduction of 23% (p > 0.05) and 62.4% (p < 0.05) in the intensity of infection, respectively, compared to the PBS control. In both experiments, the PFUR 2 compound presented results similar to those of mebendazole (40 mg/kg/5 d, IG) (p > 0.05). The results of this study demonstrated the potential of this compound as a candidate for a new anthelmintic.