<i>In vitro</i> Anthelmintic Activity of <i>Tephrosia pedicellata</i> on Two Nematodes (<i>Haemonchus contortus, Caenorhaditis elegans</i>) and Its <i>In vivo</i> Toxicity on Rats

Abstract

In Cameroon, the practice of traditional medicine in the treatment of intestinal helminthiasis is a reality and habits in the lives of traditional healers and breeders for various reasons related to their local life situations. In the valorization of medicinal plants in the treatment of digestive parasitosis as an alternative to synthetic anthelmintics, a study was carried out in order to verify their anthelmintic activity and the level of their toxicity. The present study was carried out to determine the <i>in vitro</i> anthelminthic activity of <i>Tephrosia pedicellata</i> extracts. Aqueous and hydroethanolic leaves extracts at different concentrations were tested against <i>Haemonchus contortus</i> development stages, mutant and wild type of free-living nematode <i>Caenorhabditis elegans</i>. The two plant extracts were then chemically screened and their toxicological profile was established using albino rats. Hydroethanolic extract was the most potent by killing <i>Haemonchus contortus</i> adults (LC₅₀: 0.038 mg/mL after 24 hours), infesting larvae (LC₅₀: 0.22 mg/mL after 48 hours) and inhibiting egg hatching (IC₅₀: 0.76 mg/mL after 48 hours). The two plant extracts showed same activity on <i>Caenorhabditis elegans</i> levamisole non-sensitive (LC₅₀: 0.26 mg/mL after 48 hours) and sensitive strains (LC₅₀: 0.25 mg/mL after 48 hours), showing different mode of action to that of levamisole. Several plant chemicals were identified from both extracts, with higher content of polyphenol compounds (562.91 mg GAE/g DW), flavonoids (135.96 mg RE/g DW), condensed tannins (228.50 mg CE/g DW) and saponins (206.83 mg SE/g DW) obtained with the hydroethanolic extract. No toxic effect was observed during acute toxicity study. Moreover, apart from the significant increase of platelets and Aspartate transaminase (<i>p</i>=0.001) and the glomerular inflammation in the lungs at the dose of 1000 mg/kg, no harmful variation of haematological and biochemical parameters of rats were observed. The pattern of anthelmintic activity of these extracts on <i>Caenorhabditis elegans</i> and the non-toxic effect of hydroethanolic extract provide a way for new anthelminthic drug.