Multinormal in vitro distribution of Plasmodium falciparum susceptibility to piperaquine and pyronaridine.

Background: In 2002, the World Health Organization recommended that artemisinin-based combination therapy (ACT) be used to treat uncomplicated malaria. Dihydroartemisinin-piperaquine and artesunate-pyronaridine are two of these new combinations. The aim of the present work was to assess the distribution of the in vitro values of pyronaridine (PND) and piperaquine (PPQ) and to define a cut-off for reduced susceptibility for the two anti-malarial drugs.

Metal-chloroquine derivatives as possible anti-malarial drugs: evaluation of anti-malarial activity and mode of action.

Background: Malaria still has significant impacts on the world; particularly in Africa, South America and Asia where spread over several millions of people and is one of the major causes of death. When chloroquine diphosphate (CQDP) lost its efficiency as a first-line anti-malarial drug, this was a major setback in the effective control of malaria. Currently, malaria is treated with a combination of two or more drugs with different modes of action to provide an adequate cure rate and delay the development of resistance.

1H-1,2,3-triazole tethered isatin-ferrocene conjugates: Synthesis and in vitro antimalarial evaluation.

1H-1,2,3-triazole tethered isatin-ferrocene conjugates were synthesized and evaluated for their antiplasmodial activities against chloroquine-susceptible (3D7) and chloroquine-resistant (W2) strains of Plasmodium falciparum. The conjugates 5f and 5h with an optimum combination of electron-withdrawing halogen substituent at C-5 position of isatin ring and a propyl chain, introduced as linker, proved to be most potent and non-cytotoxic among the series with IC50 values of 3.76 and 4.

1H-1,2,3-triazole tethered mono- and bis-ferrocenylchalcone-β-lactam conjugates: synthesis and antimalarial evaluation.

A series of ferrocenylchalcone-β-lactam conjugates were synthesized and evaluated against 3D7 (CQ-Sensitive) and W2 (CQ-Resistant) strains of Plasmodium falciparum. The SAR studies revealed the dependence of activities at N-1 substituent of β-lactam ring with compounds being more potent on resistant strain. The compound 9f and 9l with N-cyclohexyl substituent proved to be the most potent and non-cytotoxic among the series exhibiting IC50 values of 2.

In vitro piperaquine susceptibility is not associated with the Plasmodium falciparum chloroquine resistance transporter gene.

Background: Dihydroartemisinin-piperaquine is a new ACT that is administered as single daily dose for three days and has been demonstrated to be tolerated and highly effective for the treatment of uncomplicated Plasmodium falciparum malaria. Piperaquine was used alone to replace chloroquine as the first-line treatment for uncomplicated malaria in China in response to increasing chloroquine resistance in the 1970s. However, the rapid emergence of piperaquine-resistant strains that resulted in the cessation of its use in China in the 1980s, suggests that there is cross-resistance between piperaquine and chloroquine.