Estudo farmacognóstico e avaliação das atividades biológicas de Raphanus sativus var. oleiferus Metzg.

Abstract

The species of the Brassicaceae family are widely used in folk medicine for various therapeutic purposes. Research has shown that the radish (Raphanus sativus L.) contains many classes of biologically active phytochemicals with anti-inflammatory, antimicrobial, antioxidant and antimutagenic properties. In this context, this study aimed: to provide the quality parameters for plant drug; perform chemical analyzes and evaluate antimicrobial, antileishmanial and cytotoxic dry extract and fractions from the leaves of Raphanus sativus var. oleiferus Metzg. Initially, there was the preliminary phytochemical screening using qualitative tests and Thin Layer Chromatography in dry extract, which allowed the detection of compounds such as flavonoids, tannins and terpenes. Subsequently, the dry extract and fractions were analyzed in a mass spectrometer, which allowed the identification of some chemical constituents, based on the molecular mass and fragmentation mechanisms of molecules. Quantitative chemical analysis showed that the levels of phenolics in the fractions obtained were higher than the concentration in dry extract, and phenols were more concentrated in the butanol fraction (121,27 mg GAE/g). The content of flavonoids in the fractions, except the aqueous fraction, were also higher than those reported in dry extract, and flavonoids were more concentrated in the ethyl acetate fraction (98,02 mg EQ/g). The evaluation of the antioxidant activity in vitro, it was observed that the antiradical activity and reducing power of the fractions showed most significant results on the dry extract, and the ethyl acetate fraction showed the best results in both experiments, with percentage of sequestration DPPH radical of 83,45% and a percentage reduction of ferric ions 11,34%. The analysis of antimicrobial activity revealed that the dry extract had higher mean inhibition zones against Bacillus subtilis (18,67 mm) and is considered a statistically higher mean those produced by the fractions (p<0,05). The lowest values of minimum inhibitory concentration (MIC) were obtained for Micrococcus luteus, and the ethyl acetate fraction showed lowest minimum inhibitory concentration (0,1 mg/mL) for this micro-organism, is considered the most active fraction (80%). The bacterium Micrococcus luteus was inhibited by 50% of the tested fractions with lower or equal minimum 1 mg/mL inhibitory concentration. The dry extract and fractions do not show activity against Gram-negative bacteria, mycobacteria and fungi, and also were not active against the parasite Leishmania amazonensis. The studies showed a moderate correlation between the lowest MIC values and the highest amounts of phenolics and flavonoids, suggesting that the antimicrobial activity is not related only to these compounds, however there was a strong correlation between the best values antioxidant activity in vitro (by the method DPPH radical and by the method of reducing power) and higher amounts of phenolics and flavonoids in the extract and fractions evaluated, suggesting that phenolic compounds, especially flavonoids, are mainly responsible for the antioxidant activity in vitro plant species under study.