In vitro studies on the sensitivity pattern of Plasmodium falciparum to anti-malarial drugs and local herbal extracts

Background:The resistance of human malaria parasites to anti-malarial compounds has become considerableconcern, particularly in view of the shortage of novel classes of anti-malarial drugs. One way to prevent resistance isby using new compounds that are not based on existing synthetic antimicrobial agents.Results:Sensitivity of 100Plasmodium falciparumisolates to chloroquine, quinine, amodiaquine, mefloquine,sulphadoxine/pyrimethamine, artemisinin,Momordica charantia(‘Ejirin’)Diospyros monbuttensis(‘Egun eja’) andMorinda lucida(‘Oruwo’) was determined using thein vitromicrotest (Mark III) technique to determine the IC50ofthe drugs. All the isolates tested were sensitive to quinine, mefloquine and artesunate. Fifty-one percent of theisolates were resistant to chloroquine, 13% to amodiaquine and 5% to sulphadoxine/pyrimethamine. Highestresistance to chloroquine (68.9%) was recorded among isolates from Yewa zone while highest resistance toamodiaquine (30%) was observed in Ijebu zone. Highest resistance to sulphadoxine/pyrimethamine was recorded inYewa and Egba zones, respectively. A positive correlation was observed between the responses to artemisinin andmefloquine (P0.05). Highest anti-plasmodial activity wasobtained with the ethanolic extract ofD. monbuttensis(IC50= 3.2nM) while the lowest was obtained fromM. lucida(IC50=25nM).Conclusions:Natural products isolated from plants used in traditional medicine, which have potent anti-plasmodialactionin vitro, represent potential sources of new anti-malarial drug