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DOI: 10.1055/s-0029-1234508
In vitro antileishmanial activity of hydroalcoholic extract, fractions, and compounds isolated from leaves of Piper ovatum Vahl against Leishmania amazonensis
The medicinal plant P. ovatum is used popularly as an anesthetic [1] and anti-inflammatory [2]. We assessed the biological activity of a crude extract, a mixture of several fractions, and a pure compound obtained from Piper ovatum Vahl against promastigote and amastigote forms of Leishmania amazonensis. This study included the extraction process and bioassay-guided fractionation by the adsorption chromatography and Sephadex LH-20 method. A progressive increase in the antileishmanial effect was observed in the course of fractionation. The 50% inhibitory concentration (IC50) for dichloromethane-ethyl acetate (1:1 v/v) fraction was 2.1µg/ml and 24µg/ml; mixture of piperovatine: piperlongumune (2:3) 0.9µg/ml and 24µg/ml; piperovatine (1) 9.5µg/ml and 10µg/ml; and piperlonguminine (2) 2.5µg/ml and 9.0µg/ml, for promastigote and amastigote forms, respectively. Cytotoxicity analysis indicated that these toxic concentrations were much higher for J774G8 macrophages and Vero cells than for the protozoans. The mixture of piperovatine:piperlongumune (2:3) showed important antiprotozoal activity against the amastigote and promastigote forms of L. amazonensis, and it produced morphological changes in promastigotes and amastigotes at 0.9µg/ml and 24µg/ml (50% growth inhibition concentration), respectively, including intense cytoplasmic vacuolization, mitochondrial swelling, and mitochondrial damage, as revealed by transmission electron microscopy.
Acknowledgements The authors are grateful to CNPq for providing a research grant and fellowships.
References: [1] Correa, M.P. (1984) Dicionario das Plantas Uteis do Brasil e das Exoticas Cultivadas, vol. 1. Instituto Brasileiro de
Desenvolvimento Florestal, Rio de Janeiro.
[2] Rodrigues-Silva, D. et al. (2008)J. Ethnopharmacol. 116:569–573.