Antiplasmodial effects of a few selected natural flavonoids and their modulation of artemisinin activity

Abstract

The direct antiplasmodial effects of five structurally-related flavonoids, namely quercetin, rutin, eriodictyol, eriodictyolchalcone and catechin, were analyzed in vitro on P. falciparum. Notably, all these flavonoids, with the only exception of rutin, caused relevant inhibition of P. falciparum growth when given at 1 mM concentration. In addition, they were found to affect greatly the potent antiplasmodial activity of artemisinin, leading to significant additive and even synergistic effects. In particular, quercetin induced a pronounced synergistic effect. The observed synergisms might be conveniently exploited to design new and/or more effective combination therapies.