In vitro anthelminthic activities of Cucumis melo seeds against egg hatching, larval migration, and adult stage of Haemonchus contortus

Abstract

Haemonchosis is among the leading nematodosis of ruminants, particularly in sheep, with important economic losses. During the last decades, several approaches using anthelminthic drugs were conducted with a continuously decreasing success. Nowadays, it is well established that Haemonchus contortus is resistant to the three classes of anthelmintics in several countries. Currently, the approaches of grazing management and the use of alternative natural compounds are also implemented to control these infections. The present study aimed to evaluate the activity of the ethanolic extract of the seeds of Cucumis melo on H. contortus. For this purpose, the seeds were extracted in a 70% ethanol solution. The obtained powder was solubilized in phosphate buffer saline (PBS) at various concentrations (0 to 3.75 mg/mL) to which the assessed stages were submitted. The activity (mortality and egg hatching inhibition) was monitored at different time points (0, 12, 18, 24, and 48 h). The extract was active on diverse stages in a concentration-dependent manner. In adult females, a 100% mortality rate was reached after 24h with an LC50 of 0.5 ±0.09 mg/mL, which was significantly weaker than the levamisole control (0.33 ±0.02 mg/mL). The effect on larval migration was similar to the conventional drug effect, with IC50 values of 1.71 ± 0.10 mg/mL and 1.74 ± 0.25 mg/mL, respectively, for extract and levamisole. On larvae, the lethal activity was very similar in the presence of either levamisole or seeds extract, with an IC50 value of 0.86 ± 0.25 mg/mL and 1.19 ± 0.25 mg/mL, respectively. A qualitative phytochemical analysis revealed that the assessed extract contains alkaloids, tannins, phenolic compounds, flavonoids, glycosides, saponins, and triterpenes. The hydro-ethanolic extract of the seeds of C. melo did not induce any sign of toxicity in mice at the dose of 2000 mg/kg. Altogether, this extract is a good source of anthelminthic chemical compounds, especially those active on larval migration and egg hatching. Key-Words: Cucumis melo seeds, Anthelminthic, Haemonchus contortus, levamisole.