Evaluation of the Therapeutic Potential of Selected Herbal Plants from Baringo County, Kenya, Against Leishmania Donovani in Balb/C Mice
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Date
2023
Authors
Mogaka, Maria Divinah
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Leishmaniasis is a parasitic infection caused by Leishmania parasites. Conventional chemotherapy remains the primary approach for treating leishmaniasis despite its associated drawbacks, such as high toxicity, frequent relapses, and the need for hospitalization. Conventional drugs are also expensive. Plant-based compounds offer promising alternatives to leishmaniasis treatment because they are effective, affordable, and less associated with toxicity and resistance. This research investigated the therapeutic potential of Warburgia ugandensis, Prunus africana, and Piliostigma thonningii against Leishmania donovani in vitro and in vivo. The anti-promastigote study was done by culturing promastigotes with the test compounds. For the toxicity study, Vero cells were incubated with different concentrations of the test compounds. Serum was obtained from the mice for total immunoglobulin gamma (IgG) quantification. In vivo studies were conducted by infecting the BALB/c mice with virulent Leishmania donovani promastigotes before commencement of treatment with methanolic extracts of Warburgia ugandensis, Prunus africana, and Piliostigma thonningii and control drug, sodium stibogluconate. Treatment with the test compounds significantly reduced the parasite burden. The outcome in the mice treated with plant extracts was comparable to those treated with pentostam (P≥0.05). In the promastigote assay, all the test compounds killed more than half of the promastigotes at the highest concentration (500μg/ml). Warburgia ugandensis, P. thonningii, and P. africana reduced the number of promastigotes from 2.0 x 106 to 7.7 x 103, 72.0 x 103, and 5.0 x 103, respectively. Sodium stibogluconate had the lowest IC50 (210 μg/ml), followed by Warburgia ugandensis (IC50 of 270μg/ml). Piliostigma thonningii and P. africana exhibited lower toxicity, with IC50 values of 720 μg/ml and 500 μg/ml, respectively. Treatment with the plant extracts resulted in low production of IgG antibodies, while the untreated control group showed higher IgG levels. Antileishmanial IgG antibody levels did not differ significantly with body weight changes. However, there was a strong significant correlation between levels of IgG antibodies and parasite numbers, indicating a possibility of the potential use of IgG levels in determining disease severity. Based on these results, the study concludes that Warburgia ugandensis, Prunus africana, and Piliostigma thonningii are safe and have antileishmanial activity against L. donovani. The study recommends the extrapolation of the present results in non-human primate disease model before clinical use of the compounds.
Description
A Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science (Applied Parasitology) in the School of Pure and Applied Sciences of Kenyatta University, September, 2023.
Keywords
Evaluation, Therapeutic Potential, Selected Herbal Plants, Baringo County, Leishmania Donovani, Kenya, Balb/C Mice