Abstract

MENDIOLA MARTINEZ, Judith et al. Evaluation of the marine extracts action on Plasmodium falciparum in vitro and on aspartic proteases. Rev Cubana Med Trop [online]. 2008, vol.60, n.3. ISSN 0375-0760.

BACKGROUND: the search for new drugs or therapeutic alternatives for malaria treatment is a high priority in the struggle against this disease. At present, several studies are focused on the evaluation of aspartic protease inhibitors present in the digestive vacuole of Plasmodium falciparum, which are part of the enzymes involved in hemoglobin degradation. The few reports in literature on the purification of aspartic proteases inhibitors from marine organisms suggest that they are a practically unexplored source of this type of molecules. METHODS: marine invertebrate species Phallusia nigra, Bugula sp., Lyssodendoryx isodictyalis, Ascidia sydneiensis, Microscosmus goanus, Holothuria mexicana, Lytechinus variegatus y Echinaster sp.were detected in Puerto Esperanza area, Pinar del Rio province, on April 2006 and then ethanol extracts were prepared. In vitro antimalarial evaluation of these extracts against Plasmodium falciparum, with descriptive efficacy values being comparable with those used worldwide. The results were associated to the findings of aspartic protease model-like pepsin enzymatic action inhibition tests and to the chemical profile of secondary metabolites in these extracts. RESULTS: good reproducibility of antimalarial action of P. nigra, M. goanus y L. isodictyalis extracts was found, being the average inhibitory concentrations lower than 50 µg/mL. M. goanus extract showed a possible pepsin inhibitor. The chemical profile for ascidians corresponded to the main compounds reported in Pyuridae y Ascidiidae families. The antimalarial activity as well as the pepsin inhibitory activity might be attributed to some of the detected secondary metabolites. CONCLUSIONS: the breaking-up of these extracts is recommended in order to isolate the chemical compounds involved in the studied biological activities.

Keywords : Plasmodium falciparum; malaria; antimalarial activity; plasmepsin; aspartic proteases; pepsin; marine organisms.