The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes

γ-Tocopherol (γT) is the major form of vitamin E contained in plants and seed oils. Although it is readily metabolized in the liver, the function of the metabolites is not fully understood. This study investigated the antioxidant activities of the γT metabolite 2,7,8-trimethyl-2-(2′-carboxyethyl)-6-...

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Main Authors: Shosuke Aoyama, Tomoka Nishio, Daiki Moriya, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura, Toshiyuki Nakamura
Format: Article
Language:English
Published: MDPI AG 2024-08-01
Series:Nutraceuticals
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Online Access:https://www.mdpi.com/1661-3821/4/3/24
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author Shosuke Aoyama
Tomoka Nishio
Daiki Moriya
Shintaro Munemasa
Yoshiyuki Murata
Yoshimasa Nakamura
Toshiyuki Nakamura
author_facet Shosuke Aoyama
Tomoka Nishio
Daiki Moriya
Shintaro Munemasa
Yoshiyuki Murata
Yoshimasa Nakamura
Toshiyuki Nakamura
author_sort Shosuke Aoyama
collection DOAJ
description γ-Tocopherol (γT) is the major form of vitamin E contained in plants and seed oils. Although it is readily metabolized in the liver, the function of the metabolites is not fully understood. This study investigated the antioxidant activities of the γT metabolite 2,7,8-trimethyl-2-(2′-carboxyethyl)-6-hydroxychroman (γCEHC) in comparison to its parent compound. The pretreatment of mouse hepatoma Hepa1c1c7 cells with γCEHC showed a cytoprotective effect on the hydrogen peroxide-induced cytotoxicity to a lesser extent than that of γT. A mechanistic investigation revealed that both γ-CEHC and γT significantly up-regulated the gene and protein expressions of heme oxygenase-1 (HO-1) via the promotion of the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). Furthermore, the combination of γCEHC and γT significantly increased the gene and protein levels of HO-1 and the nuclear translocation of Nrf2, suggesting that it was an additive effect. Tin protoporphyrin IX (SnPP), a representative HO-1 inhibitor, significantly impaired the cytoprotection of γCEHC and γT against the hydrogen peroxide-induced cytotoxicity. These results suggested that not only γT but also its metabolite, γCEHC, are a promising cytoprotective factor against oxidative stress-induced cytotoxicity and that the cytoprotective effect is attributable to the cooperation of both compounds.
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spelling doaj-art-a48af58d88454bd082eb98b8fd3caff52025-08-20T01:55:45ZengMDPI AGNutraceuticals1661-38212024-08-014340941610.3390/nutraceuticals4030024The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in HepatocytesShosuke Aoyama0Tomoka Nishio1Daiki Moriya2Shintaro Munemasa3Yoshiyuki Murata4Yoshimasa Nakamura5Toshiyuki Nakamura6Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, JapanGraduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, JapanGraduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, JapanGraduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, JapanGraduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, JapanGraduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, JapanGraduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japanγ-Tocopherol (γT) is the major form of vitamin E contained in plants and seed oils. Although it is readily metabolized in the liver, the function of the metabolites is not fully understood. This study investigated the antioxidant activities of the γT metabolite 2,7,8-trimethyl-2-(2′-carboxyethyl)-6-hydroxychroman (γCEHC) in comparison to its parent compound. The pretreatment of mouse hepatoma Hepa1c1c7 cells with γCEHC showed a cytoprotective effect on the hydrogen peroxide-induced cytotoxicity to a lesser extent than that of γT. A mechanistic investigation revealed that both γ-CEHC and γT significantly up-regulated the gene and protein expressions of heme oxygenase-1 (HO-1) via the promotion of the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). Furthermore, the combination of γCEHC and γT significantly increased the gene and protein levels of HO-1 and the nuclear translocation of Nrf2, suggesting that it was an additive effect. Tin protoporphyrin IX (SnPP), a representative HO-1 inhibitor, significantly impaired the cytoprotection of γCEHC and γT against the hydrogen peroxide-induced cytotoxicity. These results suggested that not only γT but also its metabolite, γCEHC, are a promising cytoprotective factor against oxidative stress-induced cytotoxicity and that the cytoprotective effect is attributable to the cooperation of both compounds.https://www.mdpi.com/1661-3821/4/3/24γ-carboxyethyl hydroxychromanγ-tocopherolmetaboliteantioxidant activity
spellingShingle Shosuke Aoyama
Tomoka Nishio
Daiki Moriya
Shintaro Munemasa
Yoshiyuki Murata
Yoshimasa Nakamura
Toshiyuki Nakamura
The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes
Nutraceuticals
γ-carboxyethyl hydroxychroman
γ-tocopherol
metabolite
antioxidant activity
title The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes
title_full The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes
title_fullStr The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes
title_full_unstemmed The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes
title_short The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes
title_sort metabolite of γ tocopherol 2 7 8 trimethyl 2 2 carboxyethyl 6 hydroxychroman exerts intracellular antioxidant activity via up regulation of heme oxygenase 1 in hepatocytes
topic γ-carboxyethyl hydroxychroman
γ-tocopherol
metabolite
antioxidant activity
url https://www.mdpi.com/1661-3821/4/3/24
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