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Authors
Abstract(s)
Como é bastante conhecido, os seres humanos usam plantas há séculos para um amplo
espectro de aplicações, como culinária ou até mesmo medicina. Algumas plantas têm, de
facto, propriedades que podem ajudar com a saúde de vários sistemas do corpo humano
devido aos seus componentes. No caso da hortelã, mais especificamente, a Mentha
spicata L. estes componentes são fenóis, flavonoides entre outros, os quais
desempenham um papel importante na inibição do stress oxidativo, ao eliminar espécies
reativas de oxigénio (ROS) e essa capacidade de proteger do stress oxidativo é chamada
de capacidade antioxidante. Neste trabalho, o stress oxidativo foi causado nas plantas a
partir da exposição a um elemento radioativo, o radão (
222Rn). Portanto, neste estudo,
três grupos de Mentha spicata foram expostos a diferentes ambientes para que,
posteriormente, a sua capacidade antioxidante fosse comparada. Um grupo de plantas
foi exposto a uma atmosfera rica em radão (amostra A), outro, nas mesmas condições,
exceto o aerossol radioativo (amostra B), e outro grupo colocado num ambiente sem
qualquer intervenção (amostra C). Após duas semanas de exposição, mediu-se a
concentração do radionuclídeo 222Rn, nas câmaras e no ambiente, colocaram-se as
plantas a secar após o que se procedeu à extração dos seus componentes antioxidantes.
Para a avaliação da capacidade antioxidante, foram realizados testes com o radical DPPH
utilizando dois protocolos diferentes, o que nos permitiu, também, identificar qual o
melhor a utilizar nestas condições específicas. As atividades antioxidantes encontradas
nos três grupos de plantas foram calculadas pelos métodos de percentagem de sequestro
do radical (%RSA) e através do IC50 . As plantas da amostra A revelaram uma capacidade
antioxidante muito comprometida, uma vez que apresentaram uma percentagem de
sequestro mais baixo e o IC50 mais alto em comparação com as da amostra C. Por outro
lado, no caso das plantas da amostra B, verificou-se que a capacidade antioxidante
apresentava um valor intermédio quando comparado com a capacidade antioxidante das
outras duas amostras. É relevante referir, que também foi possível determinar que o
melhor protocolo, para esse ensaio e para estas condições, é o teste 1, ressaltando a
importância da padronização do estudo e da realização de ensaios complementares, não
só para avaliar as propriedades antioxidantes como também a morfologia e a
quantificação de compostos químicos nos grupos de plantas estudados.
As is widely known, humans have used plants for centuries for a wide range of applications, such as cooking or even medicine. Some plants indeed have properties that can benefit the health of various systems in the human body due to their components. In the case of spearmint, more specifically Mentha spicata L., these components include phenols, flavonoids, among others, which play an important role in inhibiting oxidative stress by eliminating Reactive Oxygen Species (ROS). This ability to protect against oxidative stress is referred to as antioxidant capacity. In this study, oxidative stress was induced in plants through exposure to a radioactive element, radon ( 222Rn). Therefore, in this study, three groups of Mentha spicata were exposed to different environments so that their antioxidant capacities could be compared afterwards. One group of plants was exposed to an atmosphere rich in radon (sample A), another under the same conditions except for the radioactive aerosol(sample B), and a third group placed in an environment without any intervention (sample C). After two weeks of exposure, the concentration of the radionuclide 222Rn in the chambers and the environment was measured, and the plants were dried before their antioxidant components were extracted. To evaluate the antioxidant capacity, DPPH radical tests were carried out using two different protocols, which also allowed us to identify the most suitable protocol to use under these specific conditions. The antioxidant activities found in the three groups of plants were calculated using the percentage of Radical Scavenging Activity (%RSA) and the IC50. The plants in sample A showed a highly compromised antioxidant capacity, as they exhibited a lower percentage of radical scavenging and a higher IC50 compared to those in sample C. On the other hand, the plants in sample B demonstrated an intermediate antioxidant capacity when compared to the antioxidant capacities of the other two samples. It is important to highlight that it was also possible to determine the most appropriate protocol for this assay and for these conditions, is test 1, emphasising the importance of standardising the study and conducting complementary tests, not only to assess antioxidant properties but also the morphology and quantification of chemical compounds in the studied plant groups.
As is widely known, humans have used plants for centuries for a wide range of applications, such as cooking or even medicine. Some plants indeed have properties that can benefit the health of various systems in the human body due to their components. In the case of spearmint, more specifically Mentha spicata L., these components include phenols, flavonoids, among others, which play an important role in inhibiting oxidative stress by eliminating Reactive Oxygen Species (ROS). This ability to protect against oxidative stress is referred to as antioxidant capacity. In this study, oxidative stress was induced in plants through exposure to a radioactive element, radon ( 222Rn). Therefore, in this study, three groups of Mentha spicata were exposed to different environments so that their antioxidant capacities could be compared afterwards. One group of plants was exposed to an atmosphere rich in radon (sample A), another under the same conditions except for the radioactive aerosol(sample B), and a third group placed in an environment without any intervention (sample C). After two weeks of exposure, the concentration of the radionuclide 222Rn in the chambers and the environment was measured, and the plants were dried before their antioxidant components were extracted. To evaluate the antioxidant capacity, DPPH radical tests were carried out using two different protocols, which also allowed us to identify the most suitable protocol to use under these specific conditions. The antioxidant activities found in the three groups of plants were calculated using the percentage of Radical Scavenging Activity (%RSA) and the IC50. The plants in sample A showed a highly compromised antioxidant capacity, as they exhibited a lower percentage of radical scavenging and a higher IC50 compared to those in sample C. On the other hand, the plants in sample B demonstrated an intermediate antioxidant capacity when compared to the antioxidant capacities of the other two samples. It is important to highlight that it was also possible to determine the most appropriate protocol for this assay and for these conditions, is test 1, emphasising the importance of standardising the study and conducting complementary tests, not only to assess antioxidant properties but also the morphology and quantification of chemical compounds in the studied plant groups.
Description
Keywords
Antioxidante Hortelã Radão Saúde