In vitro Evaluation of the Nematicidal Efficacy of Quercetin on Adult Toxocara canis

Toxocara canis is a globally distributed zoonotic parasite found in dogs' intestines, leading to various pathological damages, particularly to the intestinal flora. The larval stage causes human toxocariasis, especially in children, and may result in neurological disorders and blindness. Quercetin is a flavonoid with strong secondary metabolites and possesses medicinal advantages and antiparasitic qualities.

The assay involved  four groups, each of  10 young adult T. canis; Group I was incubated in concentrations of an ethanolic extract of quercetin, Group II in albendazole (0.2 mM/ml) (+ve control), Group III in RPMI 1640 medium with ethanol (control), and Group IV in RPMI 1640 medium only (-ve control). The potential action of quercetin against adult T. canis in vitro was detected using scanning electron microscopy, histological investigations, and enzyme analysis.

SEM declared that exposure to LC90 of quercetin caused body shrinkage, cuticle and caudal papillae swelling, and disfigurement and erosion of cuticular annulations. Compared to albendazole's effect on the treated worm's body wall, results showed that quercetin generates oxidative stress and has an extensive and variable effect on T. canis organs, including the body wall, the gut, and the genitalia.

Quercetin may set the stage for a new class of medications with remarkable potential for treating parasitic nematodes in dogs and could be extended to humans. This is the first time to employ a comprehensive study illuminating the potential action of quercetin against adult Toxocara canis in vitro.