dc.description.abstract | Background: The World Health Organization recognizes leishmaniasis as a major tropical disease with no effective vaccine against it.
Chemotherapy, the only effective way to treat all forms of the disease, is toxic and expensive. Hence, there is need for scientists to scale up the
search for new anti-leishmanial agents. The present study investigated the in vitro anti-leishmanial activity of five surface compounds of
Tarchonanthus camphoratus.
Methods: The surface exudates were obtained by rinsing the aerial parts of the plant with 100% ethyl acetate and acetone. Five compounds
were isolated from the exudates and purified by column (CC) and Thin Layer Chromatographic (TLC) techniques, respectively. The structures of
the compounds were elucidated by use of Nuclear Magnetic Resonance spectroscopy (NMR) and Electrospray Ionization High-Resolution Mass
Spectroscopy (EIHRMS). The identified compounds were then screened for anti-leishmanial activity using Leishmania donovani as the standard
strain.
Results: The five compounds were a known sesquiterpene, (-)-parthenolide (1), and four known methoxylated flavonoids; 5,7,3´,4´-tetrahydroxy3-methoxyflavone (2), 5,7,4´-trihydroxy-6-methoxyflavone (3), 5,7,3´,4´-tetrahydroxy-6-methoxyflavone (4) and 5-hydroxy-7,8-
dimethoxyflavanone (5). Compound 2 exhibited moderate anti-leishmanial activities against Leishmania donovani with IC50 value of 12.84 ± 0.62
µg/mL. (vs 0.85 ± 0.04 for pentamidine and 0.12 ± 0.02 µg/mL for amphotericin B). Compound 4 and 5 also showed anti-leishmanial activities
with IC50 values of 26.24 ± 0.14 and 23.15 ± 0.84 µg/mL, respectively. Compound 1 and 3 were inactive at the tested concentration as they
inhibited <70% of growth of L. donovani standard drug.
Conclusion: Compounds 2, 4 and 5 were active against standard strain and can be targets for synthetic modification for activity optimization. | en_US |