In vitro anthelmintic activity of aqueous extracts of five medicinal plant against eggs and the infective stage of Haemonchus contortus

The aim of the study was to determine the anthelmintic activity of Cassia abbreviata, Schotia brachypetala, Senna italica, Pappea capensis and Peltophorum africanum against egg and third larval stages of H. contortus. The bark of C. abbreviata, P. capensis and P. africanum, the root bark of S. italica and the leaves of S. brachypetala were harvested, dried at room temperature in the laboratory and thereafter extracted in hot and cold distilled water. Concentrations of 2.5, 5.0 and 7.5 mg/mL of these extracts were tested for inhibitory activity against H. contortus egg hatching and larval development. Hot and cold water extracts of P. africanum inhibited the highest percentage of eggs (25 and 22%, respectively) from hatching at the lowest concentration of 2.5 mg/mL. These extracts did also inhibit 86 and 80% of larval development, respectively. The highest rates of larval mortality were recorded for P. africanum and S. italica hot water extracts (68% and 65% within two hours at the lowest concentration and 63% and 64% for cold water extracts. The percentage of larval mortality increased as the concentrations increased. However, the experimental results were not solely dependent on extract concentration because all the third stage H. contortus larvae died within 72 hours irrespective of the level of concentration. This work therefore supports the use of the five experimental plant species used in the present study for the control of gastrointestinal nematodes by the Bapedi people of the Blouberg Municipality in Limpopo Province of South Africa and recommend that further studies like toxicity testing and in vivo trials be made to validate the use of these plants as an alternative to anthelmintic drugs. Figure content uploaded by Ana Mbokeleng Tsotetsi