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Potencial antienvelhecimento do extrato etanólico de Laurus azorica e seus constituintes químicos
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Abstract(s)
O envelhecimento da pele é essencialmente causado pela formação contínua de espécies reativas de oxigénio e por uma exposição excessiva à radiação ultravioleta, provocando alterações na matriz extracelular (ECM) devido ao aumento de atividade das enzimas colagenase, elastase, hialuronidase e tirosinase. A pesquisa de produtos naturais com potencial antienvelhecimento tem sido, nos últimos anos, foco de investigação a nível mundial, demonstrando que as plantas são uma fonte relevante de compostos biologicamente ativos para a proteção da pele. Laurus azorica é uma espécie pouco estudada relativamente às suas atividades biológicas e aos seus constituintes químicos.
O estudo desenvolvido nesta dissertação permitiu, pela primeira vez, aprofundar o conhecimento relativo à composição química e ao potencial antienvelhecimento do extrato etanólico, frações e compostos puros isolados de Laurus azorica. A fração MBP-22.1 foi analisada por CG-MS e revelou a presença de 56 compostos, entre eles alguns identificados pela primeira vez no género Laurus. A partir da mesma fração foram isoladas pela primeira vez em Laurus azorica, e caracterizadas estruturalmente usando técnicas espetroscópicas, três lactonas sesquiterpénicas, costunolide, 11,13-desidrosantonina e reinosina. Relativamente à atividade antienvelhecimento, os resultados obtidos mostraram que a fração MBP-22.2 apresentou maior poder antioxidante nos ensaios do DPPH e ABTS (IC50 = 34,67 ± 1,24 μg/mL e IC50 = 4,03 ± 0,47 μg/mL, respetivamente), cerca do dobro dos valores de IC50 obtidos para o padrão trolox, e uma excelente atividade de inibição da tirosinase (IC50 = 1,28 ± 0,35 μg/mL, comparável com o padrão ácido kójico, com IC50=1,82 ± 0,13 μg/mL). No ensaio do branqueamento do β-caroteno, o costunolide mostrou ser o mais ativo, seguido da fração MBP-22.3 (IC50 = 4,08 ± 0,76 μg/mL e 4,98 ± 0,36 μg/mL, respetivamente, cerca de 3,5 vezes e 2,92 vezes mais ativos do que o padrão ácido gálico, que apresentou IC50 = 14,56 ± 0,13 μg/mL). Entre as frações analisadas, a MBP-22.2 é, assim, a que apresenta maior potencial antienvelhecimento.
ABSTRACT: Skin aging is essentially caused by the continuous formation of reactive oxygen species and excessive exposure to ultraviolet radiation, causing changes in the extracellular matrix (ECM) due to the increased activity of collagenase, elastase, hyaluronidase and tyrosinase enzymes. The search for natural products with anti-aging potential has been the focus of research worldwide in the past few years, demonstrating that plants are a relevant source of biologically active compounds for skin protection. Laurus azorica is a barely studied species regarding its biological activities and its chemical constituents. The study developed in this dissertation allowed for the first time to increase the knowledge regarding the chemical composition and antiaging potential of the ethanol extract, fractions and pure compounds isolated from Laurus azorica. The MBP-22.1 fraction was analyzed by GC-MS and revealed the presence of 56 compounds, them some of which were identified for the first time in the Laurus genus. Three sesquiterpenic lactones, costunolide, 11,13-dehydrosantonin and reinosin, were isolated for the first time in Laurus azorica from the same fraction, and structurally characterized using spectroscopic techniques. Regarding the antiaging activity, the results obtained showed that the MBP-22.2 fraction presented greater antioxidant power in the DPPH and ABTS assays (IC50 = 34.67 ± 1.24 μg/mL and IC50 = 4.03 ± 0.47 μg/ mL, respectively), about twice the IC50 values obtained for the trolox standard, and an excellent tyrosinase inhibition activity (IC50 = 1.28 ± 0.35 μg/mL, comparable to the kojic acid standard, with IC50 = 1.82 ± 0.13 μg/ml). In the β-carotene bleaching assay, costunolide was shown to be the most active, followed by the MBP-22.3 fraction (IC50 = 4.08 ± 0.76 μg/mL and 4.98 ± 0.36 μg/mL, respectively, about 3.5 times and 2.92 times more active than the standard gallic acid, which presented IC50 = 14.56 ± 0.13 μg/mL). Among the analysed fractions, MBP-22.2 is, therefore, the one with the greatest antiaging potential.
ABSTRACT: Skin aging is essentially caused by the continuous formation of reactive oxygen species and excessive exposure to ultraviolet radiation, causing changes in the extracellular matrix (ECM) due to the increased activity of collagenase, elastase, hyaluronidase and tyrosinase enzymes. The search for natural products with anti-aging potential has been the focus of research worldwide in the past few years, demonstrating that plants are a relevant source of biologically active compounds for skin protection. Laurus azorica is a barely studied species regarding its biological activities and its chemical constituents. The study developed in this dissertation allowed for the first time to increase the knowledge regarding the chemical composition and antiaging potential of the ethanol extract, fractions and pure compounds isolated from Laurus azorica. The MBP-22.1 fraction was analyzed by GC-MS and revealed the presence of 56 compounds, them some of which were identified for the first time in the Laurus genus. Three sesquiterpenic lactones, costunolide, 11,13-dehydrosantonin and reinosin, were isolated for the first time in Laurus azorica from the same fraction, and structurally characterized using spectroscopic techniques. Regarding the antiaging activity, the results obtained showed that the MBP-22.2 fraction presented greater antioxidant power in the DPPH and ABTS assays (IC50 = 34.67 ± 1.24 μg/mL and IC50 = 4.03 ± 0.47 μg/ mL, respectively), about twice the IC50 values obtained for the trolox standard, and an excellent tyrosinase inhibition activity (IC50 = 1.28 ± 0.35 μg/mL, comparable to the kojic acid standard, with IC50 = 1.82 ± 0.13 μg/ml). In the β-carotene bleaching assay, costunolide was shown to be the most active, followed by the MBP-22.3 fraction (IC50 = 4.08 ± 0.76 μg/mL and 4.98 ± 0.36 μg/mL, respectively, about 3.5 times and 2.92 times more active than the standard gallic acid, which presented IC50 = 14.56 ± 0.13 μg/mL). Among the analysed fractions, MBP-22.2 is, therefore, the one with the greatest antiaging potential.
Description
Dissertação de Mestrado, Ciências Biomédicas, 2 de março de 2022, Universidade dos Açores.
Keywords
Laurus azorica Envelhecimento (da pele) Extrato Etanólico Potencial Antienvelhecimento Produto Natural Antiaging Potential Bioactive Compounds Ethanol Extract
Citation
Viveiros, Mariana Moniz (2022). "Potencial antienvelhecimento do extrato etanólico de Laurus azorica e seus constituintes químicos", 81 p.. Mestrado em Ciências Biomédicas. Ponta Delgada: Universidade dos Açores. [Consult. Dia Mês Ano]. Disponível em www:<http://hdl.handle.net/10400.3/6345>