A number of 235 crude extracts originally obtained from plants reputed as antiparasitic
in the traditional medicine in Sudan have been solicited from the depository of the
Faculty of Pharmacy, University of Science & Technology. The extracts were screened
against Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi trypomastigote
forms, and Leishmania donovani. Assays were based on Alamar blue protocols for T.
brucei and L. donovani, β-glactosidase assay for T.cruzi, and [3 H]-hypoxanthine incorporation
protocol for P. falciparum. Assays were performed in 96-well format, and standard
reference drugs for each parasite were used as positive controls [1]. Of the 235 plant
extracts tested, 161 samples showed inhibitory activity > 80% at 10 µg/ml, and > 50%
at 2 µg/ml against one or more of the selected parasites. Among them, 23% fulfilled
activity criteria against T. b. rhodesiense, L. donovani and P. falciparum; 18% were
active against both L. donovani and P. falciparum, and 17% were active against both
T. b. rhodesiense and P. falciparum with few extracts (< 3%) exhibited activity against
T. cruzi.
Ethyl acetate fractions of the leaves of Acacia nilotica, Guiera senegalensis, Ziziphus
spina-christi, Anogeissus leiocarpus and the bark of Terminalia laxiflora were among
the most active samples. In order to associate bioactivity of the extracts with their
HPLC chromatographic profiles coupled with their corresponding on-line spectroscopic
data, the bioactive samples were submitted to HPLC-based activity profiling [2]. The
isolation and structure elucidation of the antiparasitic compounds is well under progress.
[1] Adams, M, et al, Natural product communications, 2009. 4: 1377 – 1381.
[2] Potterat, O. and M. Hamburger, Planta medica, 2014. 80: 1171 – 1181.
