Screening of Turkish plants for antimalarial and cytotoxic effects

Abstract

Malaria is the number one parasitic disease worldwide with half of the world's population at risk [1]. Natural products have had an enormous impact in malaria chemotherapy as the majority of current antimalarial agents are natural products or derive from a natural product scaffold isolated from plants traditionally used against malaria. Malaria chemotherapy has become problematic due to resistance development by the parasite against many antimalarial drugs, so new drugs are desperately needed. Previous studies have shown that members of the Anthemis, Salvia and Scrophularia genera display significant antiplasmodial potential [2–6]. In this study, we assessed the in vitro activity of the Turkish plants Anthemis cretica subsp. anatolica, A. pestalozzae (Asteraceae), Salvia virgata (Lamiaceae), Scrophularia lucida and S. pinardii (Scrophulariaceae) against the chloroquine- and pyrimethamine/sulfadoxine-resistant Plasmodium falciparum strain K1. The cytotoxicity of the extracts was determined against KB cells to evaluate their selectivity. All plants except S. virgata are endemic to Turkish flora and unstudied. The aerial parts and the roots of the plants were extracted separately by maceration with MeOH. All crude extracts showed good to moderate inhibitory potential against P. falciparum with no toxicity towards human cells. Hence, they were subjected to a solvent partitioning scheme to yield three subextracts (n-hexane, CHCl3 and aq. MeOH). The CHCl3 subextracts exhibited the best antiplasmodial activities with IC50 values in the range of 2.2–5.6µg/ml, except for both Scrophularia roots where the n-hexane subextracts displayed the best inhibitory effects.