<i>In vitro</i> Anthelmintic Efficacy of Ethanolic Extract of Three PhenolContaining Plants against <i>Haemonchus contortus</i>

Arising from the loss of potency of the available chemical anthelmintics coupled with resistance development by gastrointestinal nematodes, this study aimed at investigating the effect of Acacia nilotica (gum arabic tree), Acacia ataxacantha (Flame Thorn) and Ziziphus mucronata (buffalo-thorn) on egg hatching and larva development of Haemonchus contortus. The selected plants were screened for their total phenol, condensed tannin, and non-tannin phenol concentrations. Anthelmintic extracts were prepared and tested at concentrations of 10, 5, 1, 0.5, 0.25 and 0.05 mg/ml in the egg hatch inhibition assay. Thiabendazole was used as a positive control, whereas distilled water was used as a negative control. The three most effective concentrations from the egg inhibition assay were used for larval development at 10, 5, and 1 mg/ml dissolved in 150, 300, and 450 μl of water. Acacia nilotica extracts of all concentrations led to greater (P<0.05) inhibition of egg hatching compared to the negative and positive control. Acacia ataxacantha extract showed an increased egg hatching inhibition than the positive control (P>0.05), while Z. mucronata extracts were less effective than the positive control (P<0.05). Acacia nilotica extract did inhibit larva development more effectively than the negative control (P<0.05), while Acacia ataxacantha showed volume-dependent effectiveness, with lower concentrations showing reduced (P<0.05) inhibition rates. Z. mucronata exhibited the least inhibitory effect on larval migration. In conclusion, Acacia species have a greater inhibitory effect on both egg hatching and larval migration than Z. mucronata.