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Malaria Research and Treatment
Volume 2011, Article ID 816250, 7 pages
http://dx.doi.org/10.4061/2011/816250
Research Article

Plasmodium falciparum: Assessment of Selectivity of Action of Chloroquine, Alchornea cordifolia, Ficus polita, and Other Drugs by a Tetrazolium-Based Colorimetric Assay

1Virology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana (UG), Legon, Ghana
2Department of Pharmacology, School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana
3Department of Clinical Pathology, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana (UG), Legon, Ghana
4Department of Immunology, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana (UG), Legon, Ghana
5Department of Pharmacology, University of Ghana Medical School, Korle Bu, Accra, Ghana

Received 28 July 2011; Accepted 12 September 2011

Academic Editor: Polrat Wilairatana

Copyright © 2011 Nana Kofi Ayisi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A tetrazolium-based colorimetric selective assay (MTT-based CSA) was developed to assess the selectivity of antimalarial drugs. This in vitro assay, unlike all others, measures the ability of drugs to indirectly protect red blood cells (RBCs) from Plasmodium-falciparum-induced destruction. Optimum incubation time and number of cells needed were 5 days and RBCs per well, respectively. A parasitemia range of 0.375% to 3% was found to be suitable for this assay. The MTT-based CSA determined anti-P. falciparum strain DD2 activity of chloroquine at a higher 50% effective concentration (EC50) value (21.0 g/mL) than the isotopic microtest (10.0 g/mL). Artesunate and oxytetracycline achieved 90% effect against DD2 with minimal or no toxicity to RBCs. Against chloroquine sensitive strain 3D7, chloroquine and Alchornea cordifolia had EC50 values of 0.025 g/mL and 4.9 g/mL respectively, and selective index (SI) values of >2,000 and >69.4 g/mL, respectively.