Full Length Research Paper

Influence of the asexual parasite biomass on in vitro susceptibility of Plasmodium falciparum to antimalarial drugs in Abidjan

Bla Kouakou Brice¹, Yavo William², Ouattara Lacinan¹, Basco Leonardo³ and Djaman Allico Joseph^{1, 4}*

¹Laboratoire de Pharmacodynamie-biochimique, Université de Cocody, 22 BP 582 Abidjan 22, Côte d’Ivoire.

²Laboratoire de microbiologie de l’Institut National de Santé Publique (INSP), BP V47 Abidjan, Côte d’Ivoire.

³Unité de Recherche Paludologie Afro-tropicale, Institut de recherche pour le développement (IRD) – Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), BP 288 Yaoundé, Cameroun.

⁴Département de Biochimie, Institut Pasteur de Côte d’Ivoire, 01 BP 490 Abidjan, Côte d’Ivoire.

*Corresponding author. E-mail: djamanj@yahoo.fr. Tél : +225 22 48 10 00 poste 6807.

Accepted 6 March, 2008

The in vitro activities of artemisinin, dihydroartemisinin (the biologically active metabolite of artemisinin derivatives), chloroquine and pyronaridine were assessed in 32 isolates of Plasmodium falciparum from Abobo in the northern of Abidjan district (Côte d’Ivoire) using a test based on the standard microtechnique recommended by the World Health Organization (WHO). The parasites densities were ranged between 8,000 and 540,000 rings/µl of blood. The geometric means 50% inhibitory concentration (GMIC₅₀) values for chloroquine, pyronaridine and artemisinin were 145.5 nM (95% confidence interval (CI) =65-226 nM), 17.69 nM (95% CI=9.1-26.3 nM) and 5.72 nM (95% CI=2.3-9.1 nM), respectively. Dihydroartemisinin was the most potent drug against chloroquine-sensitive and chloroquine-resistant isolates with a geometric mean of 2.72 nM. There was no correlation between the parasite densities and the responses to chloroquine (r²=0.01, p<0.5), pyronaridine (r²=0.13, p<0.05), artemisinin (r²=0.13, p<0.05) and dihydroartemisinin (r²=0.07, p<0.1).

Key words: Artemisinin, chloroquine, dihydroartemisinin, in vitro test, parasite biomass, pyronaridine.