Characterization of Neorautanenia brachypus (Harms) C.A.Sm tubers for anthelmintic properties in ruminant livestock

Abstract

Infections from helminths are common in livestock, resulting in economic losses. Anthelmintic developed from either killed or attenuated bacteria have been used over many centuries but their effectiveness has been lowered by anthelmintic resistance exhibited by helminths. Use of plants with anthelmintic properties has been found to offer a significant alternative pathway that is climate smart. In this research tuberous plants traditionally used in the control of helminths were explored and then focus was on Neorautanenia brachypus, a recently discovered plant to have anthelmintic properties worth exploring. In this research a systematic literature review on tuberous plants with anthelmintic properties was done and then through isolation and characterisation of phytochemicals in one such important tuber (Neorauternenia brachypus) found in Zimbabwe. Neorautanenia brachypus was futher subjected to in vitro and in vivo anthelmintic pharmacological studies. Forty-eight ethnobotanical investigations recorded 43 plants with tuber portions that were utilized to combat helminths. The phytochemical analysis involved extraction, phytochemical screening, quantitative analysis using a spectrophotometer, and Gas Chromatography-Mass Spectrometry analysis. Neorautanenia brachypus extracts contained essential oils, terpenoids, quinones, saponins, coumarins, phenols, flavonoids, alkaloids, and tannins, according to phytochemical screening tests. In terms of GAE, the total phenolic content of methanol and distilled water extracts was determined to be 365.18mg GAE/g and 89.43mg GAE/g, respectively. The Total Tannin Content of methanol and distilled water extracts was determined to be 2.33 mg TAE/g and 1.42 mg TAE/g, respectively.he pharmacological tests included a toxicity test, the Egg Hatch Inhibition Test, Larval Mortality Test, Adult Worm Mortality Test, and Faecal Egg Count Reduction Test. Neorautanenia brachypus extracts had a significant effect P<0.05, on the inhibition of egg hatching, mortality of larvae, and death of adult Eisenia foetida worms. The undiluted fresh blended tuber extract and undiluted methanol tuber extracts had a statistically significant anthelminthic activity comparable to Albendazole conventional drug diluted to 75% on egg hatch inhibition. The highest IC50 dilution 78.88% was recorded for larval mortality compared to egg hatch inhibition 71.01%. The highest mortality of Eisenia foetida worms was recorded when N. brachypus extracts were undiluted and after 24 hours of exposure. Treatments Albe100, Albe75, Blend100, Soak100, Meth100, Meth75, and DW100 showed some anthelmintic activity after 1 hour of exposure. The treatment Albe100 showed 100% worm mortality after 2 hours of exposure. Meth100, Soak100, and Blend100 showed 100% worm mortality after 6 hours of exposure. Albe75, Albe50, Albe25, Blend75, Blend50, Soak75, Soak50, Meth75, Meth50, and Meth25 iv exhibited 100% worm mortality after 24 hours of exposure. All treatments except for the negative control showed anthelmintic activity ±80 % after 24 hours of exposure. In vivo study showed that the ranks for reduction in eggs per gram for both coccidia and Strongyloides across species increased from week 1 to week 5 for the untreated group. Significant differences in eggs per gram reduction of Strongyloides (P<0.05) were noticed from week 4 to week 5. However, the ranks for reduction in eggs per gram for both coccidia and Strongyloides in goats and cattle decreased from week 1 to week 5. There was no significant change in the weight of goats and cattle between the start and end of the experimental period (P>0.05). Dioscorea deltoidea, Dioscorea bulbifera, Dioscorea alata, Gloriosa superba, Curcuma longa, Dioscorea pentaphylla, and Cyperus rotundus were shown to be the most culturally important plants for the control of helminths. As a result, conservation measures for these culturally significant plants are needed. There is also a need to investigate other tuberous plants, especially those found in Africa to identify unique compounds that are active against helminths to develop more robust anthelminthic drugs and reduce the rate at which anthelmintic resistance occurs. It was concluded that white N. brachypus were the most significant to use for extraction of phytochemicals giving a significant extract yield when air dried and Soxhlet extracted using chloroform 50%: ethyl acetate 50% as a solvent. While Methanol was the most acceptable solvent when extracting the greatest number of different classes of phytochemicals and also gave a significant extract yield. The chemical constituencies of N. brachypus confirmed by GCMS analysis affirm the therapeutic applications of the tubers. White N. brachypus tubers air-dried and Soxhlet extracted using methanol and distilled water can be used as alternatives in drug discovery because of their low toxicity to erythrocytes. The in vitro anthelmintic activity of tested plant preparations was characterized by a decrease in egg hatching, larvae, and adult worm mortality. Neorautanenia brachypus treatments may reduce the hatchability of the eggs excreted in the feces, resulting in both a reduced risk of reinfection and lightened worm loads by decreasing pasture contamination. Accordingly, N. brachypus extracts have the potential to contribute to controlling gastrointestinal parasites of ruminants. Fresh blended samples are recommended for use to control the eggs and larvae of helminths as they had acceptable IC50 concentrations in both assays. The results of this study are suggestive of promising anthelmintic activity of the herbal-based drug for both Strongyloides and coccidia in cattle and goats