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Previous issue date: 2017-09-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Pesquisas apresentam o excesso de radicais livres como um dos respons?veis por diversas doen?as degenerativas e pelo envelhecimento. Nesse contexto, desponta a utiliza??o de compostos fen?licos naturais por apresentarem ?tima atividade antioxidante e por inibirem a forma??o desses radicais. Em meio aos estudos acerca desses compostos, os antioxidantes: cis e trans-resveratrol, cis e trans-piceid e emodina ganham destaque no meio cient?fico. Trabalhos cient?ficos comprovam a presen?a desses compostos fen?licos na herb?cea ?Azedinha? (Rumex acetosa), logo, os extratos de suas ra?zes v?m sendo cada vez mais utilizadas em aplica??es farmacol?gicas. A partir disso, este trabalho teve por objetivo central a obten??o de extratos dessas ra?zes utilizando t?cnicas de extra??o com fluido supercr?tico (SFE), extra??o com l?quidos pressurizados (PLEs), extra??o com utiliza??o de micro-ondas (MAE), extra??o com solvente a baixa press?o (LPSE) e a extra??o Soxhlet. Na SFE, foi avaliado o efeito das vari?veis de processo (temperatura, vaz?o, press?o e concentra??o de cossolvente) sobre a cin?tica da extra??o, rendimento e solubilidade do extrato. Nas PLEs, tanto foram avaliadas a temperatura e a press?o, como a influ?ncia dos diferentes solventes (?gua, etanol, hexano, tolueno, acetonitrila e isopropanol) e seu uso sequenciado como PLE sequenciada. As curvas obtidas nas SFEs e PLEs foram ajustadas segundo os modelos: Mart?nez, Crank e Sovov? e seus desvios m?dios calculados. Na extra??o Soxhlet foi avaliado o uso de quatro solventes (etanol, acetonitrila, isopropanol e ?lcool terc-but?lico), enquanto que na extra??o LPSE e MAE foi utilizado o etanol como solvente. Tamb?m foi testada a utiliza??o da precipita??o por anti-solvente supercr?tico (SAS) como forma de secagem. O teor de fen?licos totais, a capacidade antioxidante dos extratos e os principais componentes do extrato foram determinados. Os rendimentos obtidos em todas as t?cnicas variaram de 0,2 a 8,7%, sendo o melhor resultado obtido na extra??o PLE com etanol. A SFE apresentou o extrato com maior concentra??o de emodina (42,8 mg/g). A concentra??o de trans-resveratrol em todos os extratos variou entre 1,0 e 5,7 mg/g, a depender da t?cnica utilizada. A atividade antioxidante e os compostos fen?licos totais resultaram em valores compreendidos entre 3,4 e 163,4 ?g/mL e 27,6 e 157,0 mg EAG/ge, respectivamente, a depender da t?cnica utilizada. A MAE obteve extratos com 130,6 mg EAG/ge, e 3,4 ?g/mL em 30 minutos de opera??o. As extra??es com fluidos pressurizados (PLEs e SFEs) demonstraram ?timos resultados, principalmente quanto ? extra??o sequencial, na qual foi poss?vel a separa??o de trans-resveratrol e emodina. / Research presents the excess of free radicals as one responsible for various degenerative diseases and aging. In this context, the use of natural phenolic compounds appears to have excellent antioxidant activity and to inhibit the formation of these radicals. In the middle of studies about these compounds, the antioxidants: cis and trans-resveratrol, cis and trans-piceid and emodin are prominent in the scientific world. Scientific works prove the presence of these phenolic compounds in the herbaceous "Azedinha" (Rumex acetosa), so extracts from their roots have been increasingly used in pharmacological applications. From this, the main objective of this work was to extract extracts of these roots using supercritical fluid extraction (SFE), pressurized fluid extraction (PLEs), microwave extraction (MAE), solvent extraction low pressure (LPSE) and Soxhlet extraction. In SFE, the effect of the process variables (temperature, flow, pressure and cosolvents concentration) on the kinetics of extraction, yield and solubility of the extract was evaluated. In the PLEs, both temperature and pressure and the influence of the different solvents (water, ethanol, hexane, toluene, acetonitrile and isopropanol) were evaluated and their use sequenced as PLE. The curves obtained in the SFEs and PLEs were adjusted according to the models: Mart?nez, Crank and Sovov? and their calculated mean deviations. In the Soxhlet extraction, the use of four solvents (ethanol, acetonitrile, isopropanol and tert-butyl alcohol) was evaluated, while in the LPSE and MAE extraction ethanol was used as the solvent. The use of supercritical anti-solvent (SAS) precipitation as a drying method was also tested. The total phenolic content, the antioxidant capacity of the extracts and the main components of the extract were determined. The yields obtained in all the techniques varied from 0.2 to 8.7%, being the best result obtained in the PLE extraction with ethanol. SFE presented the extract with the highest concentration of emodin (42.8 mg/g). The concentration of trans-resveratrol in all extracts ranged from 1.0 to 5.7 mg/g, depending on the technique used. The antioxidant activity and the total phenolic compounds resulted in values between 3.4 and 163.4 ?g/mL and 27.6 and 157.0 mg EAG/g, respectively, depending on the technique used. MAE obtained extracts with 130.6 mg EAG/g and 3.4 ?g/mL in 30 minutes of operation. Extractions with pressurized fluids (PLEs and SFEs) showed excellent results, mainly regarding sequential extraction, in which the separation of trans-resveratrol and emodin was possible.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/24505 |
| Date | 18 September 2017 |
| Creators | Santos, ?nio Rafael de Medeiros |
| Contributors | 29171156453, Costa Neto, Bento Pereira da, 01077967403, Galv?o, Elis?ngela Lopes, 03247032444, Ferreira, Marcionila de Oliveira, 02933443457, Carvalho, Ricardo Henrique Rocha de, 03633886486, Oliveira, Humberto Neves Maia de, Sousa, Elisa Maria Bittencourt Dutra de |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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