ANTITRYPANOSOMAL ACTIVITY OF EXTRACTS FROM FOUR CYANOBACTERIA ON TRYPANOSOMA BRUCEI BRUCEI
ANTITRYPANOSOMAL ACTIVITY OF EXTRACTS FROM FOUR CYANOBACTERIA ON TRYPANOSOMA BRUCEI BRUCEI
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Date
2021
Authors
AGEE, Jerry Tersoo
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Abstract
African trypanosomiases (AT) are a group of hemoparasitic diseases caused by multiple flagellated organisms of the genus Trypanosoma. The disease affects humans and livestock animals, and it is lethal if untreated, therefore, AT is of economic and global health importance. Since there is no vaccine for prevention and available drugs produce unsatisfactory outcomes, this work was aimed at discovery of new compounds with potentials for future development of new drugs for AT. Coloured microorganisms of the phylum Cyanobacteria are known to produce therapeutic secondary metabolites, which are yet to be explored for anti-Trypanosoma potentials. Therefore, in search of new anti-Trypanosoma compounds, crude methanolic extracts of four cyanobacteria (Microcystis aeruginosa EAWAG198, Microcystis flos-aquae UTEX 2677, Microcystis wesenbergii and Oscillatoria sp) were prepared and tested for trypanosomes-killing activity. The most active crude extract (M. flos-aquae) was fractionated by gel filtration chromatography with Silica gel 60-120G as the stationary phase and combination of Methanol: Ethyl acetate: Hexane solvent system as mobile phase, while purity was assessed by thin layer chromatography using Hexane: Ethyl acetate (7:3 v/v). Antitrypanosomal fractions were identified by incubating each fraction with Trypanosoma brucei brucei cells and monitoring parasite death for 2 hrs by wet mount under 400× microscopic magnifications. Wistar rats infected with T. b. brucei were treated with 30, 60 and 120 mg/kg body weight dosages of M. flos-aquae crude extract. The most active fraction (E) of M. flos-aquae was characterized by
GC/MS.. The crude extract of M. flos-aquae exhibited the highest in vitro trypanocidal activity with a percentage inhibition of 98.44 and 42.18% at 2.5 and 0.3125 mg/mL concentration, respectively, and displaying IC50 value of 0.4140 mg/mL. Fraction E exhibited the highest activity against the parasite with percentage inhibition of 74.21 % at 0.625 mg/mL with IC50 of 0.2991 mg/mL, and its subfraction 76 % inhibition (24 % survival) at the same concentration. Interestingly, the extract of M. flos-aquae suppressed parasite proliferation, and improved weight
and PCV in rats at dosages above 60 mg/kg body weight. GC/MS.In conclusion, the screened cyanobacteria are high potential sources of promising bioactive compounds that could be explored for treatment of trypanosomiasis