Phytochemical Investigation of Anti-plasmodial Metabolites from Brazilian Native Piper Species

The World Health Organization estimates there are 300 and 500 million new cases of malaria worldwide, every year, mostly in Africa, Asia, South Pacific Islands and South America. New efforts to search for novel drugs for treating malaria remain important in countries like Brazil, where many endemic areas still exist. The Amazonia region is responsible for more than 97 % of the malaria cases in the country. Two Piper species were chemically investigated in order to identify new anti-plasmodial plant secondary metabolites. The crude extract and sub-fractions from leaves of Piper lucaeanum were previously assayed against a resistant strain of Plasmodium falciparum. Hydrodistillation of the leaf essential oils (EO) from Piper lucaeanum and Piper claussenianum were analyzed by GC-MS. The main constituents found from P. lucaeanum leaf oil were alpha-pinene (30.0 %), alpha-zingiberene (30.4 %), beta-sesquiphelandrene (11.1 %), beta-bisabolene (8.9 %), while from P. claussenianum inflorescences oil nerolidol (23.7 %) and linalool (56.5 %) were the major volatile components. The oils exhibited relevant biological activity against the resistant strain of P. falciparum. P. lucaeanum leaf EO was the most promising active sample (IC50 = 2.6 mu g/mL), followed by P. claussenianum EO (IC50 = 7.9 mu g/mL), the pure nerolidol (IC50= 11.1 mu g/mL) and the linalool (IC50= 35.0 mu g/mL). These results highlight the potential of Piper oils as a source of active metabolites in the research of new anti-maliarial compounds.