Abstract:
The in vitro and in vivo antitrypanosomal activities of five plants species which are
Kigelia africana, Artemesia annnua, Bidens pilosa, Azadirachta indica and Senna
didymobotyra traditionally used in Kenya for treatment of parasitic diseases were
evaluated. Dichloromethane, Methanol, Hexane, Ethyl acetate and Aqueous
extracts of stem bark, fruits, leaves and pods of the five plants were evaluated for
in vitro activity against Trypanosoma brucei rhodesiense KETRI 3798 isolate.
Nineteen plant extracts were tested and six were active with MIC< 100g/ml while
four extracts afforded MIC values ranging from 3.91 to 62.6g/ml respectively.
Two of plant extracts, however, had low MIC values of between 3.91 and
11.42g/ml.
All the extracts tested in vitro were also tested for in vivo antitrypanosomal activity
in mice, experimentally infected with T.b. rhodesiense KETRI 3798. The results of
in vivo studies showed that only one of the extracts, Kigelia africana was able to
stop trypanosomes from establishing and multiplying in the animals. In the acute
toxicity test, administration of 250mg/kg, 500mg/kg and 1000mg/kg of plant
extracts, produced neither mortality nor significant reduction in body weight and
packed cell volume between controls and the treated animals. Moreover, no gross
lesions and histopathological changes were detectable between controls and the
treated animals indicating that the extracts were safe and effective for the
management of T.b. rhodesiense. Bio-guided fractionation, isolation and
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characterization studies of compounds from the extracts will yield information on
the active compounds and their mechanism of action.