Estudo fitoquímico e atividades antioxidante, antimicrobiana, antiprotozoária e citotóxica da espécie Banisteriopsis oxyclada (A. Juss.) B. Gates

Abstract

The use of products of natural origin the treatment of diseases is an ancient tradition that remains until the present day. This knowledge is a source of information for the development of deep studies in the search of bioactive compounds against microorganisms such as bacteria, fungi and protozoa, agents that cause several diseases and that have acquired resistance to existing treatments. In this context, the objective of this work was to evaluate the antibacterial, antifungal, antioxidant, antileishmania and cytotoxic activities of the extracts and fractions of roots, stems and leaves of Banisteriopsis oxyclada, besides the antileishmania and cytotoxic activity of leaf essential oil, and characterize or determine the structure of the chemical constituents present in the fractions and essential oil. For the development of the work, the essential oil was extracted by hydrodistillation and identified by gas chromatography coupled to the mass spectrometer. It was also prepared the ethanolic extracts of leaves, stems and roots of B. oxyclada, which were partitioned with solvents of increasing polarity, generating the fractions hexane, dichloromethane, ethyl acetate, n-butanol and the residual denominated water fraction. All extracts and fractions were submitted to phytochemical prospecting, determination of total phenol content by the Folin-Ciocalteu reagent method, evaluation of the tannins condensed by the sulfuric vanillin method, determination of the antioxidant potential by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), and evaluation of antibacterial, antifungal, antileishmania and cytotoxicity by microdilution methods in broth, as well as the analysis of the constituents present in the most active fractions by HPLC / MS. The essential oil of B. oxyclada leaves showed in its composition four major constituents: (3Z)-hex-3-en-1-ol (15.26%), (2Z)-hex-2-en-1-ol (13.00%), phytol (10.06%) and (2E)-hex-2-en-1-al (9.73%), the oil had antileishmania activity (IC50 = 32 ± 1 μg.mL- 1), to which phytol was indicated as one of the main responsible for the activity. For extracts and fractions the presence of flavonoids, terpenes, saponins and propylpropanoids were detected through phytochemical prospecting. It was also observed high content of total phenols in the ethyl acetate and n-butanol fractions of the extracts, and high concentration of condensed tannins for these same fractions, especially n-butanol. The best potential antioxidants were found in the n-butanol fractions of the extracts, among them the n-butanol fraction of the stem (EC50 = 1.28 μg.mL-1). In the antibacterial activity the most promising results were for anaerobic bacteria, specific for Porphyromonas gingivalis with MIC of 25 μg.mL-1 for dichloromethane fractions. In the antileishmania activity the best potential was found for the hexane fraction of the stem extract (IC50 = 270 ± 36 μg.mL-1). For antifungal activities the best results were for root and stem n-butanol fractions with MIC of 23.43 μg.mL-1. The n-butanol and ethyl acetate fractions of the extracts were analyzed by HPLC / MS, mainly presenting in their compositions: organic acids, flavan-3-ol, flavonols and condensed tannins. Among all activities, the most active fraction was n-butanol from the stem, which purified the pentosan-purasin compound, which showed promising antifungal activity mainly for Candida tropicalis (MIC = 1.56 μg.mL-1), indicating that the same is a candidate to act as active principle for the treatment of diseases caused by this fungus, and the compound did not present cytotoxicity.