Avaliação fitoquímica e da atividade antioxidante de Equisetum giganteum e Tagetes minuta

Abstract

The essential oil of Tagetes minuta native from Southern Brazil was obtained through hydrodistillation and analyzed for its chemical composition and antioxidant potential. Along with the essential oil, an aqueous extract was also obtained, which was partitioned by liquid-liquid extraction with ethyl acetate. The oil of the species was submitted to a chromatographic procedure to identify its constituents by gas chromatography coupled to mass spectrometry (GC-MS). The essential showed in its constitution 84% of dihydrotagetone, a compound that should be used in the future to continue studies on its biological activity and to obtain active derivatives. With the AcOEt Fraction, a chromatographic column separation was performed. Analyses by thin layer chromatography (CCD) of two fractions were indicative of quercitin (a flavonoid) and sitosterol (a phytosteroid) presence. Antioxidant activity assays were performed by the DPPH method, which is based on the capture of the DPPH (2,2- diphenyl-1-picrylhydrazyl) radical by antioxidants. The AcOEt fraction of Tagetes minuta showed high antioxidant activity. The aerial parts of Equisetum giganteum collected in southern Brazil were dried in a greenhouse at a temperature of 40 ͦ C. Then the ground plant was subjected to extraction with methanol. Extraction was performed in five 12-hour cycles. After each cycle, the material was filtered and the solvent evaporated to dryness. The extracts obtained in each cycle were combined and the resulting crude extract suspended in water and ethyl ether in a extraction funnel. After, the acid-base extraction was done. As described with T. Minuta, the crude extract of E. giganteum and its resulting fractions (Acid ether fraction and F. Ether and F. AcOEt basic fractions) were subjected to phytochemical tests to identify the major classes of secondary metabolites and were submitted to antioxidant activity assays by the DPPH method.