Estudo fitoquímico e da atividade biológica das folhas e do caule da espécie Acacia langsdorfii Benth (Leguminosaceae)

Abstract

The species Acacia langsdorfii Benth is a tree with scarce geographical distribution not happening report in the literature regarding pharmacotherapeutics properties. The genus Acacia is the largest second in the family Leguminosae and one of the largest is considered in Angiospermas, presenting more of 1.200 species presenting cosmopolitan and typical character of semi-arid hot areas distributed in tropical and temperate hot areas of everyone. The objective of this work is to contribute to the knowledge of chemical composition and biological activity of extracts derived from the leaf and stem of Acacia langsdorfii Benth, hitherto not studied. Several species of Acacia are used traditionally for the treatment of many different diseases. However, of this species, only known to their extracts show immunomodulatory activity and trypanocidal. From the hexane fraction of the stem, was isolated, by chromatographic methods, a steroid and a triterpenoid which were identified as stigmasterol and lupeol, respectively. It was isolated and purified a mixture of triterpenoid of the lupane series (where one is lupeol). The lupeol is the chemical constituent majority. From the Hexane fraction of leaves, was isolated and purified a diterpenoid and triterpenoid, which were identified as ent-atisan-7α,16α-diol and lupeol, respectively. The lupeol is the chemical constituent majority. In addition, from the ethyl acetate fraction of leaves was isolated and purified by column chromatography, two flavan-3-ols, one flavanone and two flavones which were identified by spectroscopic techniques such as catechin, epicatechin, naringenin, 4'-hydroxy-5,6,7-trimethoxyflavone and morin-3-O-rutinoside, respectively. The morin-3-Orutinoside is the chemical constituent majority of this fraction. The structures were identified using spectroscopic techniques of IR, MS, 1D and 2D NMR (H1, C13, DEPT 90 °, 135 °, DEPT, COSY, HSQC, HMBC and NOESY), and determinations of the melting point, rotation optical and comparisons with literature data. Substances ent-atisan-7α,16α-diol, morin-3-O-rutinoside, 4'-hydroxy-5 ,6,7-trimethoxyflavone were first reported in the genus. The hexane fractions derived from both the stem and leafs showed a high rate (> 90%) inhibits activity the proliferation of Plasmodium falciparum. The fractions derived from both the stem and leafs showed a high rate (> 80%) inhibits activity the linfoproliferation.