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.
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