Isolamento bioguiado de compostos com atividade antioxidante do coproduto bagaço de uva

• Ano de defesa: 2017
• Autor(a) principal: Karling, Mariéli
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso embargado
• Idioma: por
• Instituição de defesa: Universidade Tecnológica Federal do Paraná; Pato Branco; Brasil; Programa de Pós-Graduação em Tecnologia de Processos Químicos e Bioquímicos; UTFPR
• Palavras-chave em Português: Uva - Subprodutos; Antioxidantes; Fenóis; Grapes - By-products; Antioxidants; Phenols; CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA; Engenharia Química
• Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/2283

Grapes, their derivatives and by-products are considered importante source of antioxidants phenolics. The by-products can be used as ingredients for functional foods, acting as natural antioxidants and still used by the pharmaceutical and cosmetics industries. An alternative to obtain pure and biologically active compounds in relation to AA of natural extracts is to develop the bioguided study, whose objective is to monitor the biological activity of interest, which increases the chances of isolating a compound with high biological potential. However, it is known that Vitis labrusca grapes have numerous compounds that can act as natural antioxidants, however, there are few studies of this nature, which may justify the need to characterize these products, as for AA. Thus, the objective of this study was to isolate and identify compounds present in grape marc - from wine processing - that present high AA through bioguided isolation. Therefore, two extraction forms were first tested: solid-liquid followed by partition (ESL) and successive (ES). Then, the fractions (F) and extracts (E) obtained were tested for AA by different methods of analysis (ORAC, DPPH, FRAP, ABTS) and their chromatographic profiles were evaluated by High Performance Liquid Chromatography (HPLC-DAD) for define the most efficient extraction method. The ESL produced a very bioactive fraction (F-ACETATE) that stood out from the others, which followed in the process of purification by the open column chromatography (AC) technique, yielding 17 subfractions that were evaluated by thin layer chromatography (CCD) and AA. The subfractions that showed high bioactivity were then evaluated by the IC50 inhibitory concentration method, with subfractions 4 and 6, which presented IC50 lower than the quercetin standard, and also by High performance liquid chromatography coupled to Mass Spectrometry (LC-MS/MS), where several phenolic compounds were identified and quantified, among them: flavonoids - rutin, epicatechin, catechin and myricetin; The phenolic acids - gallic, caffeic, cumaric, salicylic, stilbene trans-resveratrol, among other compounds. Thus, subfractions 4, 6 and 8 were rechromatographed by CLAE-ABTS on-line and its compounds isolated by HPLC-semipreparative, yielding 12 pure compounds. The extracts, fractions and subfractions presented a high antioxidant potential for all the tests carried out, proving the biological potential of the Vitis labrusca. The results obtained may stimulate the use of these compounds by the pharmaceutical and food industries as natural antioxidants.