Contribuição ao conhecimento fitoquímico e biológico de duas espécies de rutaceae da flora paraibana

Abstract

Rutaceae is a family, mostly tropical and subtropical, comprising about 160 genera, including Metrodorea and Pilocarpus, having important medicinal and ecological properties. This family also requires attention for presenting a wide variety of secondary metabolites. This study aimed to expand the chemical and biological knowledge of the Rutaceae family by studying the species Metrodorea mollis Taub. and Pilocarpus spicatus subsp. aracatensis Kaastra. The aerial parts of the species were submitted to extraction processes, partitioning and isolation of their chemical constituents, which were then characterized by spectroscopic techniques of IR, MS and one- and two-dimensional 1H and 13C NMR, and compared to literature data. From the hexane extract of M. mollis were isolated the substances: xanthotoxin, isopimpinellin, hinokinin, savinin, lupeol and β-sitosterol. From the hexane phase of P. spicatus were identified: xanthotoxin, bergapten, imperatorin, asarinin, taraxerol acetate and brazoxido A, this last compound has been reported by the first time in the literature. The xanthotoxin and imperatorin coumarins were selected as chemical markers of P. spicatus and an analytical methodology was developed and validated to quantify by High Performance Liquid Chromatography (HPLC) the content of them in the Crude Ethanolic Extract (CEE) of P. spicatus. The proposed methodology showed to be selective, linear, accurate, precise and robust. Furthermore, it was investigated the evaluation of the antibacterial activity by the Minimum Inhibitory Concentration (MIC) and the drug resistance modulator in Staphylococcus aureus of P. spicatus CEE and isolated coumarins (bergapten, xanthotoxin, isopimpinellin, imperatorin). The CEE and coumarins presented no significant antibacterial activity. However, in the drug resistance modulation assay, the isopimpinellin reduced up to 4 times the MIC of erythromycin, and imperatorin showed the best results, with a MIC reduction of the antibiotics tetracycline (up to 2-fold), erythromycin (up to 4-fold) and norfloxacin (up to 4 times). By reducing the MIC of ethidium bromide, imperatorin is considered in fact as a putative inhibitor of the efflux system in bacteria. The results obtained in this study were promising and may encourage further research on the use of natural products.