In Vitro and In Vivo Anti-trypanosomal Activity of Dichloromethane and Methanol Crude Leaf Extracts of Dovyalis abyssinica (Flacourtiaceae) against Trypanosoma congolense Field Isolate
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Date
2014-01
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Addis Ababa University
Abstract
African Trypanosomosis is a neglected tropical disease of medical and veterinary
importance. Parasite control relies on the use of few drugs whose resistance and
unacceptable toxicities urged the investigation of new agents, preferably from natural
sources. Though Dovyalis abyssinica has been reported to posses significant trypanocidal
activity on Trypanosoma brucei in in vitro model, activity on trypanosome infected
laboratory animals has not yet been worked out. The aim of the present study was,
therefore, to investigate the in vitro and in vivo activity of D. abyssinica on T. congolense
field isolate. To evaluate the effect on motility, 200 μl T. congolense infected blood was
mixed with 50 μl of 20, 10, 2, 0.1, 0.015 mg/ml dichloromethane and methanol extracts.
Reduction or cessation of motility was then microscopically monitored for 120 minutes,
and the remaining in vitro mixtures were inoculated to healthy mice and monitored for
development of infection for 21 days. Furthermore, fifty T. congolense infected mice
were randomly grouped into ten groups of five and administered with curative doses
(250, 200, 150 and 100 mg/kg) of dichloromethane and methanol and 28 mg/kg
diminazene aceturate and dimethylsulfoxide. Following administration, parasitemia,
packed cell volume (PCV), rectal temperature, body weight and survival time were
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monitored. Suppressive doses of the extracts (250 and 200 mg/kg) were administered 24
hours post-infection and parasitemia was monitored. Dichloromethane and methanol
extracts at 20, 10, 2 mg/ml concentrations ceased parasite motility within one hour and
eliminated subsequent infectivity in mice for 21 days. Administration of dichloromethane
and methanol extracts at 250 and 200 mg/kg reduced (p<0.05) parasitemia and rectal
temperature, and improved (p<0.05) PCV, mean body weight, and mean survival time
compared to DMSO treatment. In conclusion, D. abyssinica at higher concentrations in
vitro and higher curative doses in vivo in mice posses anti-trypanosomal activity.
Keywords: Anti-trypanosomal, D. abyssinica, in vitro, in vivo, T. congolense, mice.
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Keywords
Anti-trypanosomal; D. abyssinica; in vitro; in vivo; T. congolense;mice