Estudo fitoquímico e farmacológico de Jatropha isabellei Müll Arg.

Abstract

Jatropha isabellei Müll Arg. belongs to the Euphorbiaceae family and is popularly known as yaguá-rova, turubiti and mamoneiro do campo. The decoction from the underground parts of this plant is popularly used to treat arthritis, gout, back pain and induce abortion. This work aims to determine the antioxidant capacity and antimicrobial activity of J. isabellei as well as to isolate the chemical constituents and to evaluate the popular use for gouty arthritis in an animal model. The underground parts of J. isabellei were collected in May 2008, in Cacequi, RS. The material is deposited in the herbarium of Department of Biology at Federal University of Santa Maria under register number SMDB 11.816. The plant material was dried, milled and macerated with the solvent ethanol:water (70:30, v/v). The fractions were obtained by fractionation of the crude extract with organic solvents of increase polarity (dichloromethane, ethyl acetate, n-butanol). The ethyl acetate fraction showed the best antioxidant activity against the DPPH free radical with IC50 de 14.78 ± 1.10 Sg/mL and inhibition profile similar to ascorbic acid. This fraction also showed the best values in the determination of phenolic compounds, flavonoids and condensed tannins. The crude extract and butanolic fractions showed antioxidant activity proportional to the dosage of phenolics. The dichloromethane fraction did not showed good antioxidant capacity, but allowed the isolation of a mixture of triterpenes in first time reported for this species, sitosterol 3-O-β-D glucoside and stigmasterol. The lipid peroxidation induced by Fe (II) showed that all the fractions at concentrations of 50 and 100 Sg/mL were able to inhibit significantly the production of TBARS, reaching the baseline levels when compared to control. In the antimicrobial activity the dichloromethane fraction showed the best results against the fungi S. schenckii e F. proliferatum and against bacteria of the Micrococcus genus. The crude extract of J. isabellei and its alkaloid purified fraction showed antinociceptive and antiedematogenic effects in an animal gouty arthritis model, scientifically proving the popular use of this plant.