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Abstract(s)
A utilização de plantas medicinais para a prevenção o e tratamento de doenças é uma das mais antigas práticas medicinais do homem. A determinação dos constituintes bioativos de uma planta com potencial terapêutico, oferece variadíssimas oportunidades para a descoberta e desenvolvimento de novos fármacos.
Neste contexto, o objetivo geral deste trabalho foi melhorar o conhecimento sobre as propriedades biológicas de extratos obtidos a partir do Acanthus mollis, L. (acanto), uma espécie sobre a qual são praticamente inexistentes estudos científicos, e a sua possível valorização como fonte de produtos naturais para uso terapêutico e/ou nutracêutico.
Neste estudo avaliou-se o potencial antioxidante e citotóxico de extratos metanólicos e etanólicos de folhas e flores do acanto. Para alguns grupos de metabolitos secundários (fenóis, flavonoides e alcaloides) determinaram-se alguns dos compostos fitoquímicos, bem como, a influência do procedimento de extração, usando a extracção em Soxhlet e extração assistida por ultrassons, contemplando neste caso, o tamanho de partícula. O teor médio em fenóis totais foi avaliado pelo método do reagente de Folin-Ciocalteu; para quantificar os flavonoides totais recorreu-se ao método colorimétrico com cloreto de alumínio e o teor de alcaloides totais foi estimado pelo método do reagente de Dragendorff. A atividade antioxidante foi determinada pelo teste do 2,2-difenil-1-picril-hidrazil (DPPH). A avaliação da citotoxicidade foi feita pelo teste do brometo de 3-[4,5-dimetiltiazol-2-il]-2,5-difeniltetrazólio (MTT) para a viabilidade celular e a proliferação foi analisada através do doseamento de proteínas por ácido bicinconínico (BCA).
A maioria dos extratos estudados apresentam um teor significativo de metabolitos secundários (fenóis, flavonoides e alcaloides), sendo o método de extração por ultrassons o que apresentou melhores resultados, nomeadamente para o menor tamanho de partícula. Os resultados obtidos mostraram que o teor em fenóis totais, variou entre 57,4 ± 7,67 e 200,5 ± 2,86 miligramas de equivalentes de ácido gálico (mg EAG) por grama de matéria seca. Os flavonoides totais e ao alcaloides apresentam teores que variam entre 13,8 ± 1,03 e 57,2 ± 2,24 miligramas de equivalentes de quercetina (mg EQ) por grama de matéria seca, e 50,4 ± 0,004 e 746,0 ± 0,03 miligramas de equivalentes de nitrato de pilocarpina (mg ENP) por grama de matéria seca. Os resultados para o índice de atividade antioxidante variaram entre 0,90 ± 0,03 e 1,61± 0,31 para os extratos, mostrando que todos eles apresentaram uma atividade antioxidante significativa.
Nos estudos de citotoxicidade todos os extratos provaram ser citóxicos para células do adenocarcinoma da mama humano (MCF-7) e o extrato metanólico das flores, obtido por Soxhlet, apresenta toxicidade seletiva para estas células relativamente aos fibroblastos dérmicos normais humanos (NHDF).
The use of medicinal plants for treatment, cure and prevention of diseases is one of the oldest medicinal practices of humanity. The evaluation of bioactive constituents on a plant with therapeutic potential, offers an extensive range of opportunities for the discovery and development of new drugs. In this context, the broad aim of this work was to improve the knowledge on the biological properties of extracts obtained from Acanthus mollis, L. (acanthus), a species about which there are hardly any scientific studies and its potential value as a source of natural products for therapeutic and/or nutraceutical use. This study evaluated the antioxidant and cytotoxic potential of methanol and ethanol extracts of leaves and acanthus flowers. For some groups of secondary metabolites (phenols, flavonoids and alkaloids) was determined some of phytochemical compounds, as well as the influence of the extraction procedure using the Soxhlet extraction and ultrasound-assisted extraction, comprising in this case the particle size. The average of total phenolic content was estimated by the Folin-Ciocalteu colorimetric method; flavonoids were determined by aluminum chloride colorimetric method and the total alkaloid content was estimated by the method of the Dragendorff reagent. The antioxidant activity was evaluated by the 2,2-diphenyl-1-picryl-hydrazyl radical method (DPPH). Cytotoxicity was evaluated by the 3- [4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide (MTT) assay, for cell viability and proliferation was analyzed using protein measurement using bicinchoninic acid (BCA). The majority of the studied extracts show a significant content of secondary metabolites (phenols, flavonoids and alkaloids), being the method of extraction by ultrasounds the one that presented the best results, particularly for smaller particle size. The results obtained showed that the total phenolic content varied between 57.4 ± 7.67 and 200.5 ± 2.86 milligrams of gallic acid equivalents (mg EGA) per gram of dry matter. The total flavonoids and alkaloids present content levels ranging from 13.8 ± 1.03 and 57.2 ± 2.24 milligrams of quercetin equivalents (mg EQ) per gram of dry matter and 50.4 ± 0.004 and 746.0 ± 0.03 milligrams of pilocarpine nitrate equivalents (mg EPN) per gram of dry matter. The results for the antioxidant activity index fluctuated between 0.90 ± 0.03 and 1.61 ± 0.31 for the extracts, showing that all of them presented a significant antioxidant activity. In the cytotoxicity studies all extracts proved to be citoxic to cells of the human breast adenocarcinoma (MCF-7) and the methanol extract from flowers by Soxhlet shows selective toxicity towards normal human dermal fibroblasts (NHDF).
The use of medicinal plants for treatment, cure and prevention of diseases is one of the oldest medicinal practices of humanity. The evaluation of bioactive constituents on a plant with therapeutic potential, offers an extensive range of opportunities for the discovery and development of new drugs. In this context, the broad aim of this work was to improve the knowledge on the biological properties of extracts obtained from Acanthus mollis, L. (acanthus), a species about which there are hardly any scientific studies and its potential value as a source of natural products for therapeutic and/or nutraceutical use. This study evaluated the antioxidant and cytotoxic potential of methanol and ethanol extracts of leaves and acanthus flowers. For some groups of secondary metabolites (phenols, flavonoids and alkaloids) was determined some of phytochemical compounds, as well as the influence of the extraction procedure using the Soxhlet extraction and ultrasound-assisted extraction, comprising in this case the particle size. The average of total phenolic content was estimated by the Folin-Ciocalteu colorimetric method; flavonoids were determined by aluminum chloride colorimetric method and the total alkaloid content was estimated by the method of the Dragendorff reagent. The antioxidant activity was evaluated by the 2,2-diphenyl-1-picryl-hydrazyl radical method (DPPH). Cytotoxicity was evaluated by the 3- [4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide (MTT) assay, for cell viability and proliferation was analyzed using protein measurement using bicinchoninic acid (BCA). The majority of the studied extracts show a significant content of secondary metabolites (phenols, flavonoids and alkaloids), being the method of extraction by ultrasounds the one that presented the best results, particularly for smaller particle size. The results obtained showed that the total phenolic content varied between 57.4 ± 7.67 and 200.5 ± 2.86 milligrams of gallic acid equivalents (mg EGA) per gram of dry matter. The total flavonoids and alkaloids present content levels ranging from 13.8 ± 1.03 and 57.2 ± 2.24 milligrams of quercetin equivalents (mg EQ) per gram of dry matter and 50.4 ± 0.004 and 746.0 ± 0.03 milligrams of pilocarpine nitrate equivalents (mg EPN) per gram of dry matter. The results for the antioxidant activity index fluctuated between 0.90 ± 0.03 and 1.61 ± 0.31 for the extracts, showing that all of them presented a significant antioxidant activity. In the cytotoxicity studies all extracts proved to be citoxic to cells of the human breast adenocarcinoma (MCF-7) and the methanol extract from flowers by Soxhlet shows selective toxicity towards normal human dermal fibroblasts (NHDF).
Description
Keywords
Acanthus Mollis Atividade Antioxidante Citotoxicidade. Compostos Bioativos L.