Recent developments and rationale towards new strategies for malarial chemotherapy.

The major problem facing world research for new antimalarials lies in encountered difficulties in the search for new promising paths. The past 20 years have witnessed a very impressive increase in our understanding of the biochemistry and molecular biology of malaria parasites, with attention focused on specific parasite molecules that are keys to the parasite life cycle or the induction of its pathogenesis. Directed pharmacology research has involved the identification and characterization of targets that can be specifically pharmacologically affected, including the replicating machinery of the parasites, various metabolisms such as the purine salvage pathway, and biosynthesis of pyrimidines or phospholipids. Protease inhibitors (e.g. those degrading haemoglobin), the use of iron chelators or inhibition of heme polymerization, induction of oxidative stress or inhibition of antioxidant enzymes are also investigated. Some pathways have already been validated with current antimalarials but, due to the development of resistance, complete characterization of the molecular structure of the target should allow attack of these exceptional molecules at novel and distinct sites with new drug concepts. The problem in the quest to develop new antimalarials is the fact that the results are not being materialized, but there is no lack of pharmacological targets.