Atividade antiplasmódica in vitro dos óleos essenciais de folhas e galhos de Piper marginatum Jacq. (Piperaceae).

Abstract

Malaria is a tropical, parasitic disease and one of the biggest health, social and economic problems in the world. Currently there is a great therapeutic arsenal produced from natural products and synthetic compounds for the treatment of malaria. Among the main drugs used in the treatment are chloroquine, primaquine, quinine, mefloquine, lumefantrine, artemisinin and its derivatives, and some antibiotics such as doxycycline, clindamycin and tetracycline. With the emergence of resistant parasites, a lack of an effective vaccine, a great endemicity of malaria and a biodiversity of the Amazon as a potential source of new drugs, the objective was to evaluate the pharmacological antimalarial potential of essential oils of Piper marginatum Jacq. Leaves and branches of P. marginatum were collected in the area located at the Federal University of Western Para Tapajos Unit, for subsequent obtaining of essential oils (EOs) via hydrodistillation. The chemical characterization of EOs was performed by gas chromatography coupled to mass spectrometry. To evaluate the antimalarial activity, the essential oils were submitted to in vitro schizonticidal tests with Plasmodium falciparum considered traditional microtests. For the investigation of the cytotoxicity of the essential oils of P. marginatum, assays were performed using 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazole (MTT) bromide, thereby determining LC50. The selectivity index of EOs was determined by the ratio of cytotoxic activity to antimalarial activity. The EOs presented in the chemical composition 9.59% of monoterpenes, 75.35% of sesquiterpenes and 14.88% of phenylpropanoids for the EO obtained from branches and 16.97% of monoterpenes; 45.22% sesquiterpenes 1.98% diterpenes, 24.82% phenylpropanoids and 7.05% unidentified for the EO obtained from leaves. The leaf EO IC 50 was 4.94 μg / mL for sensitive P. falciparum strains and IC 50 of 5.14 μg / mL for resistant chloroquine strains. The EO of the branches had IC 50 of 5.34 μg / mL and 5.54 μg / mL for sensitive and resistant strains, respectively. The evaluation of the antiplasmodic activity showed that the leaf EO presented better activity when compared to the EO result of the branches against P. falciparum.