Detection of Molecular Markers of Antimalarial Drug Resistance in Plasmodium Falciparum from South-Western Nigeria

The widespread of drug resistant Plasmodium falciparum has led to a rise in malaria- associated mortality most especially in sub-Saharan Africa. Falciparum malaria was confirmed by microscopic examination of Giemsa-stained blood samples of patients who presented with fever in selected State Hospitals in Ogun State, Southwestern Nigeria. Molecular methods were employed to detect the markers of resistance of P. falciparum to Chloroquine, sulphadoxine/pyrimethamine,and artesunate in Ogun State, Southwestern Nigeria. DNA was extracted from patient blood using the QiaAmp DNA Blood Minikit extraction method. Nested Polymerase Chain Reaction followed by Restriction Fragment Length Polymorphisms (PCR/RFLP) were used for the detection of P. falciparum chloroquine resistance transporter (Pfcrt), P. falciparum multidrug resistance 1 (pfmdr1), P. falciparum dihydrofolate reductase (Pfdhfr), P. falciparum dihydropteroate synthase (Pfdhps) and P. falciparum sarco/endoplasmic reticulum calcium-dependent ATPase (SERCA) PfATPase6 genes. Pfcrt (K76T ) Pfmdr1 (mdr 1 ) Pfdhfr (S108N), and Pfdhps (K540E) resistant genes were detected among the isolates while resistant SERCAPfATPase6 gene which codes for artemisinin resistance was not detected in the population

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 considerable concern, particularly in view of the shortage of novel classes of anti-malarial drugs. One way to prevent resistance is by using new compounds that are not based on existing synthetic antimicrobial agents. Results: Sensitivity of 100 Plasmodium falciparum isolates to chloroquine, quinine, amodiaquine, mefloquine, sulphadoxine/pyrimethamine, artemisinin, Momordica charantia (‘Ejirin’) Diospyros monbuttensis (‘Egun eja’) and Morinda lucida (‘Oruwo’) was determined using the in vitro microtest (Mark III) technique to determine the IC50 of the drugs. All the isolates tested were sensitive to quinine, mefloquine and artesunate. Fifty-one percent of the isolates were resistant to chloroquine, 13% to amodiaquine and 5% to sulphadoxine/pyrimethamine. Highest resistance to chloroquine (68.9%) was recorded among isolates from Yewa zone while highest resistance to amodiaquine (30%) was observed in Ijebu zone. Highest resistance to sulphadoxine/pyrimethamine was recorded in Yewa and Egba zones, respectively. A positive correlation was observed between the responses to artemisinin and mefloquine (P<0.05), artemisinin and quinine (P<0.05) and quinine and mefloquine (P<0.05). A negative correlation was observed between the responses to chloroquine and mefloquine (P>0.05). Highest anti-plasmodial activity was obtained with the ethanolic extract of D. monbuttensis (IC50 = 3.2nM) while the lowest was obtained from M. lucida (IC50 =25nM). Conclusions: Natural products isolated from plants used in traditional medicine, which have potent anti-plasmodial action in vitro, represent potential sources of new anti-malarial drugs