Avaliação da atividade biológica de extratos vegetais contra leishmania (viannia) guyanensis (kinetoplastida: trypanosomatidae) e análise de frações semi-purificadas de caesalpinia ferrea martius (fabales - caesalpiniaceae)

Abstract

Leishmaniasis is a world public health problem wide considered by the World Health Organization as one of five infectious endemic diseases of major relevancy. The search for leishmanicids agents with fewer side effects is one of the greatest challenges in modern research, and is increasingly related to the uses of medicinal plants and other natural products. The species Caesalpinia ferrea Martius widely distributed in Brazil it is popularly used for many therapeutic purposes, including the treatment of various infections like those caused by leishmaniasis, making it a promising tests of biological activity against leishmania. The objective of this study was to evaluate by bioassays the activity of hexane and methanol extracts against protozoa, analyzing semi-purified fractions obtained from the most active. The fruits of C. ferrea were collected at the National Institute of Amazon Research, V8’s Campus in the City of Manaus - AM and processed in the departments of Natural Products and leishmaniasis and Chagas Diseases at INPA. The studies were performed with the whole fruit and its separate parts, coconut shell and seed. Hexane e methanol crude extracts were prepared from the fruits, coconut shell and seeds, which were tested to evaluate the biological activity in vitro against promastigotes of the stationary phase of the protozoan Leishmania (Viannia) guyanensis. The extracts were analyzed by thin layer chromatography Comparison (CCDC) and Nuclear Magnetic Resonance (NMR) to determine the chromatographic profile. All biological assays were carried out experimentally in vitro in microplates containing 106/mL promastigotes to axenic cultures of L. (V.) guyanensis evaluating the inhibitory activity and stimulating parasite growth. The most active crude extract was submitted to CCDC and fractionation by partition líquid-líquid resulting in semi-purified fractions that were evaluated for their chemical composition. The results showed that the epicarp methanolic extract of C. ferrea, showed anti-leishmanial activity for L. (V.) guyanensis in the concentration of 20 mg/mL/24h. However, contrary to expectations, there was a stimulatory effect on L. (V.) guyanensis by the hexanic extract obtained from the fruit seed of C. ferrea. Chemically analyzing the coconut shell and fruits methanolics extracts of, which showed anti-leishmanial activity, we verified the presence of substances such as chlorophyll, flavonoids, xanthones, tannins, triterpenes and saponins as major constituents, and shows antioxidant activity. The results showed that the methanolics extracts of coconut shell and fruitsof C. ferrea can be considered as an promising alternative in the treatment of cutaneous leishmaniasis and should be undertaken pharmacological and toxicological tests in vivo of extract, making other fractioning in order to isolate the substances responsible for the anti-leishmanial activity.