Estudo fitoquímico de Justicia wasshauseniana (Acanthaceae), Tetrapterys acutifolia e Lophanthera lactescens (Malpighiaceae) e atividades biológicas

Abstract

This work describes the isolation and structural determination of special metabolites isolated from leaf and stem of J. wasshauseniana (Acanthaceae), popularly known as a coati tail, which was collected in the Paracambi, RJ; Leaves and stem of T. acutifolia (Malpighiaceae), popularly known as cipó-roão, were collected in the Barra do Piraí-RJ and leaf and bark of L. lactescens (Malpighiaceae), popularly known as lain of lold, was collected on the campus of the Federal Rural University of Rio de Janeiro Campus Seropédica RJ. Some chemical and biological activities of extracts of the last species were evaluated. Chromatographic fractionation of leaf and stem extracts from the Justicia wasshauseniana (Acanthaceae), from the leaf and stem of Tetrapterys acutifolia (Malpighiaceae), and from the leaves and bark of Lophanthera lactescens (Malpighiaceae) besides analysis of fractions by chromatographic and spectroscopic techniques led to the isolation and identification of constituents of different classes of special metabolites. including new alkaloids from J. wasshauseniana. From the leaves and stem of J. wasshauseniana were identified a triglyceride with the unsaturated acyl moiety, an unsaturated carboxylic acid, a mixture of steroids (β-Sitosterol, estigmasterol and campesterol) and glycosyl steroids (3-O--D-glucopyranosylsitosterol and 3-O--D-glucopyranosylstgmasterol), a disaccharide (-D-glucopyranosyl-O--D-fructofuranoside (Sucrose) and the alkaloids acid (N-fenil-o-metileno-O-5)-3-hidroxi-5-carboxy-lactam, and N(fenil-o-metileno-O-5)-3-hidroxi-5-(carboxilato de 2,3-dihidroxipropionila)--lactama), described for the first time in the literature. From the leaves and stem of T. acutifolia were identified a mixture of sitosterol, stigmasterol, 5,6-dihydro-sitosterol. and 5,6-dihydro-20-21,22-23,24-28,25-26-campesterol, ascorbic acid, in addition to sucrose and an ecdysteroid, 2S,3R,5R,9R,10R,13R,14S,17S,20S-2,3,14,20,24,25-hexahidroxicolest-7-en-6-ona (Pinatasterone). The extracts from the leaves and barks of L. lactescens, besides the mixture of sitosterol, stigmasterol and campesterol, was isolated the nortriterpene known as coreolidene. Besides to confirm the structure correction proposed in the literature of this nortriterpene, the absolute stereochemistry was defined as methyl 4R,5R,6R,7S,8S,9S,10S,13R,14S,15S,16R,17S,18R,21S,22S-friedelan-1,2-en-3-carboxy-24- 5- [1-acetoxy-ethylidene] -6,7,15,16-tetracetoxy-18-hydroxy-21,22-oxy-29-methylene-30-carboxylate. The structures were defined through analysis of IR, 1D and 2D NMR, mass spectra and circular dichroism besides some methyl and acetyl derivatives. The methanolic extracts from the stem and leaves of J. wasshausseniana and the methanolic extracts and fractions of the stem and leaves of T. acutilfolia were tested against the free radicals of DPPH. The extract from the stem of J. wasshausseniana was more active than leaf extract. The fraction of hexane from the leaves of T. acutilfolia did not present a good antioxidant activity, a greater activity was observed for the ethyl acetate fraction of stem and leaves of this plant. The pharmacological tests of the antinociceptive and anti-inflammatory potentials of the L. lactescens bark methanolic extract and the methanolic extract of leaves of J. wassahueniana were carried out, in which they showed positive results in the tested activities.