<i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells

The increasing incidence of colorectal cancer and inflammatory diseases poses a major health concern, with oxidative stress playing a significant role in the onset of these pathologies. Factors such as excessive consumption of sugar-rich and fatty foods, synthetic food additives, pesticides, alcohol...

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Main Authors: Carlos Martins-Gomes, Fernando M. Nunes, Amélia M. Silva
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Antioxidants
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Online Access:https://www.mdpi.com/2076-3921/13/11/1287
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author Carlos Martins-Gomes
Fernando M. Nunes
Amélia M. Silva
author_facet Carlos Martins-Gomes
Fernando M. Nunes
Amélia M. Silva
author_sort Carlos Martins-Gomes
collection DOAJ
description The increasing incidence of colorectal cancer and inflammatory diseases poses a major health concern, with oxidative stress playing a significant role in the onset of these pathologies. Factors such as excessive consumption of sugar-rich and fatty foods, synthetic food additives, pesticides, alcohol, and tobacco contribute to oxidative stress and disrupt intestinal homeostasis. Functional foods arise as a potential tool to regulate redox balance in the intestinal tract. Herbs (such as <i>Thymus</i> spp.) have long been screened for their antioxidant properties, but their use as antioxidants for medicinal purposes requires validation in biological models. In this study, we addressed the potential antioxidant protection and preventive effects of extracts from two thyme species at the intestinal level, as well as their molecular mechanisms of action. Caco-2 cells were pre-exposed (4 h) to aqueous (AD) and hydroethanolic (HE) extracts of <i>Thymus carnosus</i> and <i>Thymus capitellatus</i>, followed by a recovery period in culture medium (16 h), and then treated with <i>tert</i>-butyl-hydroperoxide (TBHP; 4 h), before analyzing cell viability. The effect of the extracts’ main components was also analysed. Cellular oxidative stress, cell-death markers, and the expression of antioxidant-related proteins were evaluated using flow cytometry on cells pre-exposed to the AD extracts and salvianolic acid A (SAA). Results showed that pre-exposure to AD extracts or SAA reduced TBHP-induced oxidative stress and cell death, mediated by increased levels of nuclear factor erythroid 2-related factor 2 (Nrf2) protein. The protective activity of <i>T. capitellatus</i> AD extract was shown to be dependent on NAD(P)H quinone dehydrogenase 1 (NQO1) protein expression and on increased glutathione (GSH) content. Furthermore, ursolic acid induced cytotoxicity and low cellular antioxidant activity, and thus the presence of this triterpenoid impaired the antioxidant effect of HE extracts. Thus, AD extracts show high potential as prophylactic dietary agents, while HE extracts arise as a source of nutraceuticals with antioxidant potential.
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spelling doaj-art-828d7c7cb6414a3481142606b033c43e2024-11-26T17:46:47ZengMDPI AGAntioxidants2076-39212024-10-011311128710.3390/antiox13111287<i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 CellsCarlos Martins-Gomes0Fernando M. Nunes1Amélia M. Silva2Centre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Cell Biology and Biochemistry Laboratory, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801 Vila Real, PortugalChemistry Research Centre-Vila Real (CQ-VR), Food and Wine Chemistry Laboratory, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801 Vila Real, PortugalCentre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Cell Biology and Biochemistry Laboratory, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801 Vila Real, PortugalThe increasing incidence of colorectal cancer and inflammatory diseases poses a major health concern, with oxidative stress playing a significant role in the onset of these pathologies. Factors such as excessive consumption of sugar-rich and fatty foods, synthetic food additives, pesticides, alcohol, and tobacco contribute to oxidative stress and disrupt intestinal homeostasis. Functional foods arise as a potential tool to regulate redox balance in the intestinal tract. Herbs (such as <i>Thymus</i> spp.) have long been screened for their antioxidant properties, but their use as antioxidants for medicinal purposes requires validation in biological models. In this study, we addressed the potential antioxidant protection and preventive effects of extracts from two thyme species at the intestinal level, as well as their molecular mechanisms of action. Caco-2 cells were pre-exposed (4 h) to aqueous (AD) and hydroethanolic (HE) extracts of <i>Thymus carnosus</i> and <i>Thymus capitellatus</i>, followed by a recovery period in culture medium (16 h), and then treated with <i>tert</i>-butyl-hydroperoxide (TBHP; 4 h), before analyzing cell viability. The effect of the extracts’ main components was also analysed. Cellular oxidative stress, cell-death markers, and the expression of antioxidant-related proteins were evaluated using flow cytometry on cells pre-exposed to the AD extracts and salvianolic acid A (SAA). Results showed that pre-exposure to AD extracts or SAA reduced TBHP-induced oxidative stress and cell death, mediated by increased levels of nuclear factor erythroid 2-related factor 2 (Nrf2) protein. The protective activity of <i>T. capitellatus</i> AD extract was shown to be dependent on NAD(P)H quinone dehydrogenase 1 (NQO1) protein expression and on increased glutathione (GSH) content. Furthermore, ursolic acid induced cytotoxicity and low cellular antioxidant activity, and thus the presence of this triterpenoid impaired the antioxidant effect of HE extracts. Thus, AD extracts show high potential as prophylactic dietary agents, while HE extracts arise as a source of nutraceuticals with antioxidant potential.https://www.mdpi.com/2076-3921/13/11/1287cellular antioxidant activitynuclear factor erythroid 2-related factor 2 (Nrf2)<i>Thymus carnosus</i><i>Thymus capitellatus</i>salvianolic acid ACaco-2 cells
spellingShingle Carlos Martins-Gomes
Fernando M. Nunes
Amélia M. Silva
<i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells
Antioxidants
cellular antioxidant activity
nuclear factor erythroid 2-related factor 2 (Nrf2)
<i>Thymus carnosus</i>
<i>Thymus capitellatus</i>
salvianolic acid A
Caco-2 cells
title <i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells
title_full <i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells
title_fullStr <i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells
title_full_unstemmed <i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells
title_short <i>Thymus</i> spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells
title_sort i thymus i spp aqueous extracts and their constituent salvianolic acid a induce nrf2 dependent cellular antioxidant protection against oxidative stress in caco 2 cells
topic cellular antioxidant activity
nuclear factor erythroid 2-related factor 2 (Nrf2)
<i>Thymus carnosus</i>
<i>Thymus capitellatus</i>
salvianolic acid A
Caco-2 cells
url https://www.mdpi.com/2076-3921/13/11/1287
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