Potent antiplasmodial extracts from Cameroonian Annonaceae.
OBJECTIVE
In a search for new antimalarial leads, we have carried out a preliminary ethnopharmacological study with the aim of evaluating the in vitro antiplasmodial activity of extracts from thirteen Annonaceae species growing in Cameroon, and of assessing the acute toxicity of promising fractions in Swiss albino mice.


METHODS
Plants were selected on the basis of an ethnobotanical survey carried out in four sites in centre and south regions of Cameroon (Yaoundé neighbourhoods, Kon-Yambetta, Ngobayang and Mbalmayo) on Annonaceae plants locally used to treat malaria and related symptoms. The choice of the sites was mainly based on environmental factors enabling mosquito breeding, cosmopolitan areas regrouping people from different cultural origins, areas with limited access to health centers, and areas with people relying exclusively on traditional medical practices. Collected materials were extracted by maceration in 95% ethanol. The crude extract was partitioned using organic solvents and the fractions afforded were evaluated for antiplasmodial activity in culture against the W2 strain of Plasmodium falciparum. Promising fractions (methanol fractions) were assessed for their acute toxicity in Swiss albino mice.


RESULTS
From the results achieved, 37 (31.3%) out of 118 extracts tested exhibited antiplasmodial activity, with IC(50) values ranging from 1.07 μg/ml to 9.03 μg/ml. Of the active extracts, 29 (78.4%) were methanol fractions, 21 (72.4%) of which inhibited the parasites with IC(50)<5 μg/ml. The promising fractions proved to be safe through oral administration in mice.


CONCLUSIONS
The activities and toxicity profiles of methanol fractions indicate that they deserve to be further investigated in detail for antimalarial lead discovery.
Laboratory of Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon. ffefe@yahoo.com
Fabrice Fekam
FF
Boyom
Patrick Valere Tsouh
PV
Fokou
Lauve Rachel Tchokouaha
LR
Yamthe
Alvine Ngoutane
AN
Mfopa
Eugénie Madiesse
EM
Kemgne
Wilfred Fon
WF
Mbacham
Etienne
E
Tsamo
Paul Henri Amvam
PH
Zollo
Jiri
J
Gut
Philip J
PJ
Rosenthal
D000818:Animals; D029061:Annonaceae / Q000737:chemistry*; D000962:Antimalarials / Q000494:pharmacology*; D002163:Cameroon; D005260:Female; D007928:Lethal Dose 50; D008297:Male; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology*; D010961:Plasmodium / Q000187:drug effects*
D000962:Antimalarials; D010936:Plant Extracts