Abstract:
Haemonchus contortus is one of the most prevalent nematode parasite in small ruminants worldwide. Development of anthelmintic resistance and high cost of synthetic drugs prompted evaluation of microencapsulated medicinal plant extracts as alternative drugs. The aim of this study was to evaluate the anthelmintic activity of microencapsulated Prosopis juliflora extracts against H. contortus isolated from naturally infected sheep. Roots and leaves of P. juliflora were collected from Marigat, Baringo County, air-dried, ground and extracted with ethanol. The extracts were subjected to phytochemical screening and evaluated for anthelmintic activity according to standard procedures. The mean percentage extraction yields for roots and leaves ethanolic extract were 11.2% and 5.6%, respectively. The phytochemical screening on both ethanolic extracts tested positive for tannins, saponins, alkaloids, flavonoids and sterols. The amounts of saponins, alkaloids and tannins on roots were 5.9, 1.7, 1.8 and leaves 2.4, 3.7, 0.17 percent respectively. The results showed that microencapsulated leaves ethanolic extract at drug to polymer ratio of 2:1, leaf ethanolic extract and albendazole at 2.0 mg/ml concentration exhibited 100% on inhibition of egg hatchability. However, there was no statistically significant difference (p= 0.272) in mean percentage egg hatch inhibition on both leaf and root ethanolic extracts in comparison with albendazole which showed a significant difference (p= 0.000) in activity. In larval mortality assay, all microencapsulated extracts of P. juliflora (leaves and roots) induced over 50% mortality of larvae at the highest concentration used (2mg/ml). Albendazole required a maximum concentration of 0.25 mg/ml to induce 100% larval mortality. There was a significant difference (p= 0.000) in larval mortality compared to that of egg hatchability. The results on adult mortality assay indicate that there was a significant difference (p< 0.05) in mean percentage adult mortality of H. contortus at different concentrations and ratios. All the assays showed extract concentration dependent response. The EC50 values from microencapsulated leaves and roots extracts on adult mortality assay, ranged from 1.950 to a maximum of 26.87 mg/ml. These values were significantly different (p< 0.05) compared with albendazole (0.05 mg/ml) and leaves
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ethanolic extracts (0.71 mg/ml). In conclusion, this study has shown that microencapsulated P. juliflora extracts had anthelmintic activity on eggs, larvae and adults of H. contortus parasite. The activity could be related to the presence of phytochemicals such as saponins, alkaloids and tannins. Therefore, microencapsulated herbal drug may be evaluated further as novel anthelmintic drug for control of H. contortus in small ruminants and thus in vivo studies are recommended to ascertain its efficacy.
