Antileshmanial Activity of Senna didymobotrya Methanolic Leaf Extracts on Leishmania major

Leishmaniasis is a neglected tropical disease with high morbidity and mortality. Current treatments, such as pentavalent antimonials, are expensive, highly toxic, and face increasing parasite resistance. We evaluated the antileishmanial activity of methanolic leaf extracts of Senna didymobotrya as a potential complementary treatment. Leaves of S. didymobotrya were collected from Kabarak University Botanical Garden and extracted using methanol through cold maceration. Eight-week-old inbred BALB/c female mice were obtained from the Kenya Medical Research Institute (KEMRI) for macrophage assays. Leishmania major (Strain IDUB/94=NLB-144) parasites were cultured in Schneider’s insect medium (SIM) and used to infect macrophages. The infected macrophages were treated with varying concentrations of S. didymobotrya extract, while Pentostam served as a positive control and untreated infected macrophages as a negative control. A nitric oxide assay was conducted to assess immunomodulatory effects. The results indicated that S. didymobotrya extract exhibited antileishmanial activity, with a minimum inhibitory concentration (MIC) of 2 mg/ml, compared to Pentostam’s MIC of 250 μg/ml. The extract also demonstrated anti-amastigote activity by reducing parasite multiplication within macrophages. However, it did not significantly stimulate nitric oxide production compared to the standard treatment. In conclusion, methanolic leaf extracts of S. didymobotrya possess promising antileishmanial properties against L. major. Although its MIC value was higher than that of Pentostam, further research is needed to elucidate its mode of action and enhance its efficacy.