Phytochemical Screening, Acute Toxicity and Anti-Rabies Activities of Extracts of Selected Ethiopian Traditional Medicinal Plants
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Date
2019-09-20
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Addis Ababa University
Abstract
Despite the existence of safe and effective vaccines, rabies disease still causes an estimated 59,000 human deaths a year in the endemic areas in Asia and Africa. In most developing countries people believe to cure rabies with different traditional and religious treatment rather than seeking effective post exposure prophylaxis. The objective of this study was, therefore, to investigate the phytochemical constituents, acute toxicity and antirabies activity of crude extracts of the leaves of Justicia schimperiana and Ricinus communis and the stem bark of Croton macrostachyus. Extraction was done by maceration technique. Standard procedures were used to test the presence of various phytochemicals. For the determination of acute toxicity and antirabies activities, Organization for Economic Corporation and Development (OECD) Guideline No.423 was used. Different concentrations of extracts (0.4, 0.8, 1.6, 3.2, 6.4 and 12.8 mg/ml) were tested for their cytotoxic effect on vero cells through 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide (MTT) assay. The mean cytotoxic concentration (CC50) was estimated and the antirabies assay was carried out using the minimal cytotoxic concentration of extracts. The phytochemical screening result has revealed the presence of alkaloids, flavonoids, phenols, steroids, tannins and terpenoids in all plant extracts screened. The toxicity evaluation of the extracts revealed that they are slightly toxic. The antirabies assay result showed that all plant extracts had a moderate to good antirabies potential. The 80 % methanol extracts exhibited higher antirabies activity compared to the other extracts under investigation. The present study concluded that these medicinal plants have possessed different phytochemicals that helps in the anti-rabies properties of the studied plants commonly used in Ethiopia. Further study on the mechanism of those phytochemicals must be elucidated for the potential as antirabies agent. Evaluation of those medicinal plants for their long-term toxicity would also be very important.
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Anti-Rabies, Cytotoxicity, Pathogenicity, Phytochemicals, Traditional Medicinal Plants