Caracterização de extratos de Senecio brasiliensis e Solanum viarum obtidos por diferentes métodos extrativos com aplicabilidade na agricultura

Abstract

The present work aimed to investigate the potential of plants used empirically in agriculture, as well as evaluate different extractive methods, carry out the characterization of the obtained extracts and analyze their allelopathic potential. In the first experimental stage, the yield and chemical composition of the root and fruit matrices of Solanum viarum and flowers, leaves and stalks of Senecio brasiliensis were evaluated, using different extraction techniques: Soxhlet, maceration, supercritical fluids extraction (SFE), ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE) and microwave hydrodiffusion and gravity (MHG). For SFE, the solvent used was carbon dioxide with pressure values set between 150 and 250 bar and temperature values between 40°C and 60°C. In UAE, a hydroalcoholic solution (60% water/40% ethanol) was used as solvent and the effects of ultrasound intensity (17–85 W/cm²) and pulse cycle (0.5–1.0) in the extraction yields of matrices were evaluated. For PLE, ethanol, water and their mixtures were used as solvents at a pressure of 10 MPa and temperatures between 30°C and 60°C, with ethanol concentration of 70 to 100% (v/v). For MHG, water and ethanol were used as solvent in a proportion of 60 ml ethanol and 40 ml water, under atmospheric pressure and 400 W of power. For comparison, conventional extractions with Soxhlet and maceration were performed. All extracts obtained were analyzed for chemical composition in a gas chromatography system coupled to a mass spectrometer. In the second step, the allelopathic potential of the extracts obtained by ultrasound under the condition of 85 W/cm² power and 1 pulse cycle for the matrices of two species under study was evaluated, at a concentration of 100 mg/ml, using as a solvent ethanol. The fungicidal activity was tested in fungi Fusarium graminearum and Sclerotinia sclerotiorum and the herbicidal action was tested in pre-emergence of Cucumis sativus seeds. The results of this thesis demonstrate that the different extraction techniques are efficient technologies for extraction of compounds from S. viarum and S. brasiliensis, the matrix extracts are a potential source of bioactive compounds and both species studied show a great antifungal and herbicide potential.