The ferriprotoporphyrin IX (FP) molecules released by intraerythrocytic malaria parasites during hemoglobin digestion are converted to beta-hematin and are stored in the parasites' food vacuoles. It has been demonstrated in cell-free medium that the incorporation of FP into beta-hematin under physiological conditions requires a catalyst from parasite lysates or pre-formed beta-hematin. In the p...

Background and objectives: There are several methods to assess the in vitro capability of heme inhibitory activity of antimalarial compounds; most of them require some specific equipment or toxic substances and sometimes the needed materials are not accessible. Regarding the necessity and importance of optimizing and standardizing experimental conditions, the present s...

The formation of hemozoin (malaria pigment) has been proposed as an ideal drug target for antimalarial screening programs. In this study, we used an improved, cost-effective and high-throughput spectrophotometric assay to screen plant extracts for finding novel antimalarial plant sources. Fifteen extracts with different polarity from three Iranian Artemisia species, A. ciniformis, A. biennis an...

Pyronaridine, 2-methoxy-7-chloro-10[3',5'-bis(pyrrolidinyl-1-methyl-)4'hydroxyphenyl]aminobenzyl-(b)-1,5-naphthyridine, a new Mannich base schizontocide originally developed in China and structurally related to the aminoacridine drug quinacrine, is currently undergoing clinical testing. We now show that pyronaridine targets hematin, as demonstrated by its ability to inhibit in vitro beta-hemati...

The mechanism of action of artemisinin antimalarials may be ascribed to C-centered radicals that alkylate biomolecules or to the peroxide moiety, which inhibits a specific, as yet undefined, target (4). It is also proposed that artemisinins kill the parasite through inhibition of hemozoin formation, thereby allowing buildup of toxic heme monomer (1, 2, 5). Artemisinin and dihydroartemisinin may...

The great potential of magnetic field enriched surface enhanced resonance Raman spectroscopy (SERRS) for early malaria diagnosis has been demonstrated previously. This technique is able to detect β-hematin, which is equivalent to a malaria biomarker (hemozoin) in Raman features, at a concentration of 5 nM. In this study, we present the optimization of nanoparticles used in the magnetic field en...

The formation of hemozoin (malaria pigment) has been proposed as an ideal drug target for antimalarial screening programs. In this study, we used an improved, cost-effective and high-throughput spectrophotometric assay to screen plant extracts for finding novel antimalarial plant sources. Fifteen extracts with different polarity from three Iranian Artemisia species, A. ciniformis, A. biennis an...

In malaria pathophysiology, divergent hypotheses on the inhibition of hematin crystallization posit that drugs act either by the sequestration of soluble hematin or their interaction with crystal surfaces. We use physiologically relevant, time-resolved in situ surface observations and show that quinoline antimalarials inhibit β-hematin crystal surfaces by three distinct modes of action: step pi...