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Authors
Abstract(s)
O fruto de Prunus avium L., vulgarmente conhecido como cereja, é uma excelente fonte de
fitoquímicos, nomeadamente compostos fenólicos, que são metabolitos secundários das
plantas e caracterizam-se por possuir pelo menos um anel aromático com um ou mais grupos
hidroxilo ligados. Estes compostos têm despertado o interesse dos consumidores nos últimos
anos pelos inúmeros benefícios que apresentam para o organismo. A sua atividade
antioxidante, bem como todos os processos desencadeados pela mesma estão na origem
desses mesmos efeitos benéficos.
Assim, com este estudo pretendeu-se determinar in vitro o impacto da biodisponibilidade na
bioatividade dos compostos fenólicos presentes nas cerejas. Para isso, recorreu-se a uma
linha celular derivada do tumor gastrointestinal (Caco-2) como modelo para simular a
absorção gastrointestinal, tendo-se primeiramente averiguado a permeabilidade e integridade
da monocamada formada pela linha celular, e posteriormente avaliou-se a permeabilidade da
mesma aos compostos fenólicos contidos num extrato de cereja da variedade Saco digerido in
vitro e não digerido. Decorrida incubação procedeu-se à quantificação dos compostos
fenólicos que permeabilizaram a membrana simulada recorrendo à técnica de HPLC-DAD.
Paralelamente, foi avaliado o efeito da passagem pela barreira celular na atividade
antioxidante dos extratos já referidos, tendo-se para isso usado o ensaio com 2,2-difenil-1-
picrilidrazil (DPPH).
Os resultados obtidos demonstraram que os compostos fenólicos do fruto de Prunus avium L.
após sofrerem um processo de digestão simulada, foram absorvidos pela barreira celular,
tornando-se biodisponíveis. Porém, estes mesmos compostos apresentavam-se em
concentrações diminuídas relativamente às iniciais. Contrariamente, quando o mesmo extrato
de cereja não sujeito a digestão foi colocado em contacto com a mesma camada de células
apenas a quercetina-3,4’-di-O-glicosídeo conseguiu tornar-se biodisponível. Também a
atividade antioxidante foi maior antes da passagem pela monocamada celular, sendo a
percentagem de inibição de DPPH de 0% após esse mesmo processo. Ao contrário do que se
verificou após a incubação com o extrato digerido in vitro, a integridade da monocamada
celular ficou alterada e a permeabilidade da mesma aumentou aquando da incubação com o
extrato bruto. Isto sugere que os compostos presentes no extrato bruto e que interferem com
as junções intercelulares, após o processo digestivo, sofrem modificações, ficando mais
bioacessíveis, uma vez que são degradados originando compostos mais pequenos. Foi possível
verificar que a absorção ficou facilitada, aumentando a sua biodisponibilidade. Estes fatores
mostraram-se relevantes para a integridade e permeabilidade celular. Tendo em conta os resultados obtidos, este estudo sugere que a digestão é um processo
indispensável para que ocorra absorção, pois sem ele o conteúdo fenólico da matriz alimentar
não fica bioacessível. Também a função da barreira celular ficou comprometida aquando da
incubação com o extrato não digerido.
É de realçar que o presente trabalho é apenas um ensaio in vitro e são necessárias
investigações futuras de modo a corroborar os resultados apresentados. Assim, outros estudos
in vitro e in vivo devem ser realizados.
The fruit of Prunus avium L., commonly known as sweet cherry, is an excellent source of phytochemicals, namely phenolic compounds, which are secondary metabolites of plants and are characterized by having at least one aromatic ring with one or more hydroxyl groups attached. These compounds have aroused the interest of consumers in the recent years due to numerous benefits they present to the body. Its antioxidant activity, as well as all the processes triggered by it, are responsible for these same beneficial effects. Thus, this study aimed to determine in vitro the bioavailability impact on the bioactivity of the phenolic compounds present in cherries. To do this, a cell line derived from the gastrointestinal tumor (Caco-2) was used, and the permeability and integrity of the monolayer formed by the aforementioned cell line was first investigated. After this the permeability was evaluated to the phenolic compounds contained in the cherry extract of the cultive Saco digested and undigested. After incubation, the phenolic compounds that permeabilized the simulated membrane were quantified using the HPLC-DAD technique. At the same time, the antioxidant activity of the same compounds in the above-mentioned extracts was evaluated and an assay was carried out with 2,2-diphenyl-1-picrylidrazyl (DPPH). The results obtained demonstrated that the phenolic compounds of the fruit of Prunus avium L. after undergoing a simulated digestion process, were absorbed by the cellular barrier, becoming bioavailable, however, in lower concentrations. Nevertheless, when the same cherry extract not subjected to digestion was placed in contact with the same cell layer only quercetin-3,4'-di-O-glycoside was able to become bioavailable. Also, the antioxidant activity was higher before passage through the cell monolayer, and the percentage of DPPH inhibition was 0% after this same process. Contrary to what was found after incubation with the in vitro digested extract, the integrity of the cell monolayer was altered and the permeability of the monolayer increased upon incubation with the crude extract. This suggests that the compounds which are present in the extract and interfere with the intercellular junctions undergo modifications after the digestion process and become more bioavailable, since they are degraded into smaller molecules. Also the absorption has been facilitated, increasing bioavailability. These factors have been found relevant for both cell integrity and permeability. Considering the results obtained, this study suggests that digestion is an crucial process for the absorption, since without it the phenolic content of the food matrix does not become bioaccessible. Also, the function of the cell barrier was compromised upon incubation with the undigested extract. It should be noted that the present work is only an in vitro assay and future investigations are qe necessary to corroborate the presented results. Thus, other in vitro and in vivo studies should be performed.
The fruit of Prunus avium L., commonly known as sweet cherry, is an excellent source of phytochemicals, namely phenolic compounds, which are secondary metabolites of plants and are characterized by having at least one aromatic ring with one or more hydroxyl groups attached. These compounds have aroused the interest of consumers in the recent years due to numerous benefits they present to the body. Its antioxidant activity, as well as all the processes triggered by it, are responsible for these same beneficial effects. Thus, this study aimed to determine in vitro the bioavailability impact on the bioactivity of the phenolic compounds present in cherries. To do this, a cell line derived from the gastrointestinal tumor (Caco-2) was used, and the permeability and integrity of the monolayer formed by the aforementioned cell line was first investigated. After this the permeability was evaluated to the phenolic compounds contained in the cherry extract of the cultive Saco digested and undigested. After incubation, the phenolic compounds that permeabilized the simulated membrane were quantified using the HPLC-DAD technique. At the same time, the antioxidant activity of the same compounds in the above-mentioned extracts was evaluated and an assay was carried out with 2,2-diphenyl-1-picrylidrazyl (DPPH). The results obtained demonstrated that the phenolic compounds of the fruit of Prunus avium L. after undergoing a simulated digestion process, were absorbed by the cellular barrier, becoming bioavailable, however, in lower concentrations. Nevertheless, when the same cherry extract not subjected to digestion was placed in contact with the same cell layer only quercetin-3,4'-di-O-glycoside was able to become bioavailable. Also, the antioxidant activity was higher before passage through the cell monolayer, and the percentage of DPPH inhibition was 0% after this same process. Contrary to what was found after incubation with the in vitro digested extract, the integrity of the cell monolayer was altered and the permeability of the monolayer increased upon incubation with the crude extract. This suggests that the compounds which are present in the extract and interfere with the intercellular junctions undergo modifications after the digestion process and become more bioavailable, since they are degraded into smaller molecules. Also the absorption has been facilitated, increasing bioavailability. These factors have been found relevant for both cell integrity and permeability. Considering the results obtained, this study suggests that digestion is an crucial process for the absorption, since without it the phenolic content of the food matrix does not become bioaccessible. Also, the function of the cell barrier was compromised upon incubation with the undigested extract. It should be noted that the present work is only an in vitro assay and future investigations are qe necessary to corroborate the presented results. Thus, other in vitro and in vivo studies should be performed.
Description
Keywords
Atividade Antioxidante Biodisponibilidade Caco-2 Compostos Fenólicos Prunus Avium L.