Submitted to: Biological and Pharmaceutical Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2007
Publication Date: 10/1/2007
Citation: Bajsa, J.N., Singh, K., Nanayakkara, D., Duke, S.O., Rimando, A.M., Evidente, A., Tekwani, B.L. 2007. A Survey of Synthetic and Natural Phytotoxic Compounds and Phytoalexins as Potential Antimalarial Compounds. Biological and Pharmaceutical Bulletin. 30(9):1740-1744. Interpretive Summary: Several natural and synthetic phytotoxins, including herbicides, were tested for anti-malarial activity in assays made directly on the microbe. The rationale for this is that the malarial parasite has a vestigial chloroplast that might be susceptible to these types of compounds. We found good activity with some of the compounds, but there was no correlation between whether the compound had a chloroplast target site and its activity against the malaria parasite.
Technical Abstract: Objectives: The apicomplexan parasites pathogens such as Plasmodium spp. possess an apicoplast, a plastid organelle similar to those of plants. The apicoplast has some essential plant-like metabolic pathways and processes, making these parasites susceptible to inhibitors of these functions. The main objective of this paper is to determine if phytotoxins with plastid target sites are more likely to be good antimalarial compounds than are those with other modes of action. Methods: The antimalarial activity of compounds was tested in vitro on a chloroquine (CQ) sensitive (D6, Sierra Leone) strain of Plasmodium falciparum. Results: In this study, we provide activity of almost 50 such compounds tested, as well as a few phytoalexins, against malaria. Endothall, anisomycin, and cerulenin had sufficient antimalarial action to be considered as new lead antimalarial structures. Some derivatives of fusicoccin possessed markedly improved antimalarial action than the parent compound. Conclusions: Our results do not suggest that phytotoxins with plastid targets are better antimalarials than those that act at other molecular sites. The herbicides, phytotoxins and the phytoalexins reported here with significant antimalarial activity may be useful leads for identification of new antimalarial drug targets and may also be used as lead structures for new antimalarial drug discovery.