In Vitro and In Vivo Anthelmintic Effects of Medicinal Plants Against Gastrointestinal Nematodes of Goats at Haramaya University Farm, Eastern Ethiopia
A study was conducted to investigate the in-vitro and in vivo anthelmintic effects of crude methanol extracts of Azadirachta indica, Vernonia amygdalina, Nicotiana tabacum, Moringa oleifera, Croton macrostachyus, and Hagenia abyssinica against gastrointestinal nematodes of goats. The plants were collected from East Hararghe Zone during November 2017 to March 2018. Leaves from each plant species were separately collected, dried, ground, and crude methanol soluble was extracted. Three graded concentration of crude extract of 100mg/ml, 50mg/ml and 25mg/ml were prepared and evaluated for in vitro anthelmintic effects using standard techniques of larval development assay, larvae inhibition and egg hatch tests. For the egg hatch test, the wells containing about 100 eggs/ml were incubated at 27°C for 48 hours and evaluated based on the characteristics such as dead, embryonated, or hatched egg to L1. Similar egg concentrations were used for larval development assays and exposed to various concentrations of the plant extracts to evaluate the development of eggs to infective larvae (L3) over a period of six to seven days. For the larvae inhibition test, approximately 100 larvae were placed into test tubes containing plant extracts. The results were evaluated by adding a drop of warm water and counting of active and dead larvae at an interval of three hours, for a total period of twelve hours. For the in vivo trial, 1g/kg of the crude extract of the plants were prepared and administered via oral drenching. High (p<0.05) percentage of in vitro egg hatchability inhibition was recorded for Croton macrostachyus as compared to the other plant species while the lowest inhibition was recorded for Moringa oleifera and Hagenia abyssinica. Nicotiana tabacum caused 100% larval (L3) mortality within three hours at 100mg/ml and 50mg/ml while the other plants extract did not show substantial effect. The development of larvae from L1 to L3 was arrested following exposure to extracts of Nicotiana tabacum, Vernonia amygdalina, and Croton macrostachyus. In vivo test result showed 96.6% fecal egg count reduction in crude extract of Nicotiana tabacum drenching, which was better (p<0.05) than the other plants tested and the positive control. In general, the in vitro and in vivo results show that crude extracts of Nicotiana tabacum, Vernonia amygdalina, and Croton macrostachyus were promising for the control of gastrointestinal nematodes. Thus, further studies are required to evaluate toxicity, dose and active ingredients/chemicals determination of crude extracts of these plants for possible production of alternative natural anthelmintic.