In Vitro Anthelmintic Activity and Phytochemical Screening of Crude Extracts of Three Medicinal Plants against Haemonchus Contortus in Sheep at Haramaya Municipal Abattoir, Eastern Hararghe

The current study was carried out to evaluate the anthelmintic efficacy of crude methanolic extracts of leaves of Croton macrostachyus and Nicotiana tabacum and rhizome parts of Zingiber officinale on nematode parasite, Haemonchus contortus. For these objectives, adult worm mortality assay (AWMA) was conducted on adult H. contortus to investigate the in vitro adulticidal effect of crude extracts from March to October 2021 G.C. The percentage yield of crude 99.9% methanolic extracts was 53%, 78%, and 44% for C. macrostachyus, N. tabacum, and Z. officinale, respectively. Phytochemical analysis using standard techniques was also used to detect secondary metabolites contained in the plants. The study revealed the presence of secondary metabolites such as tannins, flavonoids, steroids, and terpenoids in all extracts, which are considered to be the chemical components that are responsible for the wide therapeutic activities of several medicinal plants. In in vitro study, four graded concentrations of the crude extracts (500 mg/ml, 250 mg/ml, 125 mg/ml, and 62.5 mg/ml) were tested at regular time intervals, and parasite viability for 8 hours was recorded in triplicate. Albendazole (1.25 mg/ml) and distilled water were used as the positive and negative controls, respectively. At 4 hr posttreatment, the 62.5 mg/ml, 125 mg/ml, and 250 mg/ml concentrations of C. macrostachyus, N. tabacum, and Z. officinale extracts have caused significantly higher mortality (P < 0.05) compared to the albendazole. Methanolic extracts of C. macrostachyus, N. tabacum, and Z. officinale produced mortality of adult H. contortus significantly (P < 0.05) to the level of 93%, 83%, and 50% at concentration of 125 mg/ml at 4 hr posttreatment and meanwhile at 6 hr produced 100%, 100%, and 90%, respectively, at the same concentration. On the other hand, albendazole (1.25 mg/ml) killed 60% and 80% of the parasites at 4 hr and 6 hr posttreatment, respectively. Concentrations of all the extracts had showed a comparable and strong nematocidal effect on H. contortus having no significant difference with that of the positive control (P > 0.05) at 8 hr posttreatment period. Hence, the current study revealed that the extracts from three plants have potential anthelmintic effect, and we recommend further study on fractionating each component separately and validating the materials using other parasite developmental stages are warranted.