<i>In vitro</i> Effects of <i>Anogeissus leiocarpus</i> and <i>Adansonia digitata</i> on Two Life-cycle Stages of <i>Haemonchus contortus</i>, a Gastrointestinal Parasite of Small Ruminants

Abstract

This study evaluated the <i>in vitro</i> anthelmintic activity of aqueous and hydroethanolic extracts of <i>Anogeissus leiocarpus</i> and <i>Adansonia digitata</i> leaf powder at 75; 150; 300; 600; 1200 and 2400 µg/mL against <i>H. contortus</i>, using the egg hatch test and the adult worm motility inhibition test. For egg hatch inhibition, the both plants showed significant concentration-dependent efficacy and were significantly more effective (p < 0.001) at the highest concentrations (1200 and 2400 µg/mL) than at the lowest. The hydro ethanolic extract of <i>A. leiocarpus</i> showed the highest inhibition (R² = 0.9963) and the aqueous extract of the same plant showed the lowest inhibition (R² = 0.9742). The 50% inhibitory concentration (IC50) of the <i>A. leiocarpus</i> aqueous and hydro ethanolic extracts (86.19 and 72.5 µg/mL) were 3 times lower than those of the A. digitata extracts (302 and 269.5 µg/mL). Mobility of adult worms was also concentration dependent (p<0.05); and also dependent on incubation time (p<0.01). At 2400 μg/mL, all adult worms were immobile after 6 h of exposure, whereas at the lowest concentration (75 μg/mL), all adult worms were immobile after 36 h of exposure. Extracts from both plants had similar activity. Finally, the results of the present study suggest that the both plants studied have anthelmintic properties <i>in vitro</i> which would explain their use by livestock farmers. However, <i>in vivo</i> tests should be performed to confirm these properties in vivo as well.