Evaluation of biological activities of grape (Vitis viniferaL.) stems for potential application in the cosmetic and pharmaceutical industries
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2020-04-28
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A produção de uva gera grandes quantidades de subprodutos, comoo engaço de uva. Este resíduo é maioritariamentedescartado em áreas abertas, onde a sua difícil deterioração originaproblemas ambientais e compromete a sustentabilidade das empresas.Visto que,este subprodutopossui compostos bioativos, com benefíciospara a saúde, asuaaplicação como fonte de compostosfenólicos em novos produtos pode ser promissora, contudo, é essencialgarantir que este subproduto é seguro para os consumidores.Assim, o objetivo deste trabalho foianalisarespectrometricamente e fluorimetricamente o conteúdo mineralde seis variedades de engaço de uva, procedendo-se depois à determinação da composição fenólica por métodos colorimétricos (fenóis totais, orto-difenóis e flavonóides), e à identificaçãoe quantificaçãodos compostos maioritáriospor HPLC. Asatividades biológicas dos extratos de engaço foram também avaliadas, nomeadamente:a atividade antioxidante através dos métodos ABTS, DPPH e FRAP; a atividade antimicrobiana pelos métodos de difusão em disco e Concentração Mínima Inibitória contra isolados bacterianos de pacientes hospitalares; a atividade anti-inflamatória na linha celular RAW 264.7; e a atividade anti-envelhecimento através da capacidade de inibição dasatividadesdas enzimas tirosinasee elastase. Os resultados demonstraram que o engaço de uvapossui um alto teor de minerais essenciais, sendo os mais abundantes o Ca e K, com concentrações médias de1.41 e 24.45 g/Kg peso seco, respetivamente. Relativamente aos metais tóxicos, o Al apresentou maior abundância com uma concentraçãomédia de 200.80mg/Kg peso seco. Também para a composição fenólica foram observadas diferenças significativas, com teores variando de 30,91 ± 0,73 a 96,12 ± 8,14 mg ácido gálico/g peso seco, 32,17 ± 1,04 a 77,26 ± 5,31 mg ácido gálico/g peso seco, e 25,76 ± 1,14 a 65,14 ± 0,65 mg catequina/g peso secopara os fenóis totais, orto-difenóis e flavonóides, correspondentemente. Ademais, onze compostosfenólicosforam identificados por HPLC, sendo a catequinao composto mais abundante (0,44 ± 0,02 a 2,03 ± 0,08 mg/g peso seco).Em relação à atividade antioxidante, atingiram-sevalores de 0,84 ± 0,06, 0,64 ± 0,05 e 1,03 ± 0,06 mmolTrolox/g peso secopara os métodosABTS, DPPH e FRAP, respetivamente,enquanto que, para a atividade antimicrobiana, os extratos apresentaram alta eficácia contra bactérias Gram-positivas. A capacidade anti-inflamatóriados extratosmostrouinibições de 16,52%a 35,25%na produção de NO, epela primeira vez, os extratosde engaçoapresentaramatividades anti-tirosinase e anti-elastase, cominibições máximas de 53,82%e 98,02%, respetivamente. O engaço demonstrou ser ricoem minerais essenciaisecompostos fenólicos, que aliadoscom as suas propriedades biológicas, indicam queeste subprodutopode ser utilizado no desenvolvimento de novos antibióticos contraa resistênciabacterianaaos antibióticos, em fármacos que diminuam/eliminem a inflamação, em produtos cosméticos,e emsuplementos alimentarese vitaminaspara humanos.Porém, estudos adicionais sobre asuatoxicidade são necessários, assimcomo, descobrir os compostos fenólicos responsáveis pelaspropriedadesbiológicas. No entanto, numa primeira fase, é vital um maior cuidado na utilização de fertilizantes/pesticidas, para queeste subprodutose torne totalmenteseguropara ser aplicado nas indústrias cosmética, farmacêutica e alimentar.
Grape production generates large amounts of by-products, such as grape stem. This residue is mostly discarded in open areas, where its difficult deterioration causes environmental problems and compromises the sustainability of the companies. Since this by-product hasbioactive compounds with health benefits, its application as a source of phenolic compounds in new products may be promising, however, it is essential to ensure that this by-product is safe for consumers.Thus, the objective of this work was to analyze spectrometrically and fluorimetrically the mineral content of six grape stem varieties, followed by the determination of phenolic composition by colorimetric methods (total phenols, ortho-diphenols, and flavonoids), and the identification and quantification of major compounds by HPLC. The biological activities of grape stem extracts were also evaluated: the antioxidant activity through the ABTS, DPPH, and FRAP assays; the antimicrobial activity by the disk diffusion and Minimum Inhibitory Concentration methods against bacterial isolates from hospital patients; the anti-inflammatory activity byRAW 264.7 cell line; and the anti-aging activity by the capacity to inhibit the activity of tyrosinase and elastase enzymes. The results demonstrated that grape stem has a high content of essential minerals, being the most abundant Ca and K, with average concentrations of 1.41 and 24.45 g/Kg dry weight, respectively. Regarding thetoxic metals, Al presented higher abundance with an average concentration of 200.80 mg/Kg dry weight. Significant differences were also observed for phenolic composition, with contents ranging from 30.91 ± 0.73 to 96.12 ± 8.14 mg gallic acid/g dry weight,32.17 ± 1.04 to 77.26 ± 5.31 mggallic acid/g dry weight, and 25.76 ± 1.14 to 65.14 ± 0.65 mg catechin/g dry weightfor total phenols, ortho-diphenols and flavonoids, respectively. In addition, eleven compounds were identified by HPLC, with catechin beingthe most abundant compound (0.44 ± 0.02 to 2.03 ± 0.08 mg/g dry weight).Concerning to antioxidant activity, values of 0.84 ± 0.06, 0.64 ± 0.05 and 1.03 ± 0.06 mmol Trolox/g dry weightwere obtained for the ABTS, DPPH and FRAP methods, respectively, while for antimicrobial activity, the extracts presented high efficacy against Gram-positive bacteria.The anti-inflammatory capacity of the extracts showed inhibitions of 16.52%to 35.25% in NO production, and for the first time, grape stem extracts exhibited anti-tyrosinase and anti-elastase activities, with maximum inhibitions of 53.82%and 98.02%, respectively. Grape stem has been shown to be rich in essential minerals and phenolic compounds, which, combined with their biological properties, indicate that this by-product can be used in the development of new antibiotics against bacterial resistanceto antibiotics, in drugs that decrease/eliminate inflammation, in cosmetic products, and in dietary supplements and vitaminsfor humans. Nevertheless, further studies on their toxicity are needed, as well as discovering the phenolic compounds responsible for biological activities. But first, greater care in the use of fertilizer/pesticides is vital for this by-product to become totallysafe to be appliedin the cosmetic, pharmaceutical, and food industries.
Grape production generates large amounts of by-products, such as grape stem. This residue is mostly discarded in open areas, where its difficult deterioration causes environmental problems and compromises the sustainability of the companies. Since this by-product hasbioactive compounds with health benefits, its application as a source of phenolic compounds in new products may be promising, however, it is essential to ensure that this by-product is safe for consumers.Thus, the objective of this work was to analyze spectrometrically and fluorimetrically the mineral content of six grape stem varieties, followed by the determination of phenolic composition by colorimetric methods (total phenols, ortho-diphenols, and flavonoids), and the identification and quantification of major compounds by HPLC. The biological activities of grape stem extracts were also evaluated: the antioxidant activity through the ABTS, DPPH, and FRAP assays; the antimicrobial activity by the disk diffusion and Minimum Inhibitory Concentration methods against bacterial isolates from hospital patients; the anti-inflammatory activity byRAW 264.7 cell line; and the anti-aging activity by the capacity to inhibit the activity of tyrosinase and elastase enzymes. The results demonstrated that grape stem has a high content of essential minerals, being the most abundant Ca and K, with average concentrations of 1.41 and 24.45 g/Kg dry weight, respectively. Regarding thetoxic metals, Al presented higher abundance with an average concentration of 200.80 mg/Kg dry weight. Significant differences were also observed for phenolic composition, with contents ranging from 30.91 ± 0.73 to 96.12 ± 8.14 mg gallic acid/g dry weight,32.17 ± 1.04 to 77.26 ± 5.31 mggallic acid/g dry weight, and 25.76 ± 1.14 to 65.14 ± 0.65 mg catechin/g dry weightfor total phenols, ortho-diphenols and flavonoids, respectively. In addition, eleven compounds were identified by HPLC, with catechin beingthe most abundant compound (0.44 ± 0.02 to 2.03 ± 0.08 mg/g dry weight).Concerning to antioxidant activity, values of 0.84 ± 0.06, 0.64 ± 0.05 and 1.03 ± 0.06 mmol Trolox/g dry weightwere obtained for the ABTS, DPPH and FRAP methods, respectively, while for antimicrobial activity, the extracts presented high efficacy against Gram-positive bacteria.The anti-inflammatory capacity of the extracts showed inhibitions of 16.52%to 35.25% in NO production, and for the first time, grape stem extracts exhibited anti-tyrosinase and anti-elastase activities, with maximum inhibitions of 53.82%and 98.02%, respectively. Grape stem has been shown to be rich in essential minerals and phenolic compounds, which, combined with their biological properties, indicate that this by-product can be used in the development of new antibiotics against bacterial resistanceto antibiotics, in drugs that decrease/eliminate inflammation, in cosmetic products, and in dietary supplements and vitaminsfor humans. Nevertheless, further studies on their toxicity are needed, as well as discovering the phenolic compounds responsible for biological activities. But first, greater care in the use of fertilizer/pesticides is vital for this by-product to become totallysafe to be appliedin the cosmetic, pharmaceutical, and food industries.
Descrição
Dissertação de Mestrado em Enologia e Viticultura
Palavras-chave
Engaço de uva , Minerais essenciais