Screening of dietary antioxidants against mitochondria-mediated oxidative stress by visualization of intracellular redox state

Abbreviations: ALA, (±)-α-lipoic acid; α-toco, DL-α-tocopherol; Bio-PQQ™, pyrroloquinoline quinone disodium salt; CHO, chinese hamster ovary; ETC, electron transport chain; FRET, fluorescence resonance energy transfer; GSTA2, glutathione S-transferase A2; HO-1, heme oxygenase-1; Lyc, lycopene; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; Nrf2, nuclear factor erythroid-2-related factor 2; PQQ, pyrroloquinoline quinone; Res, resveratrol; ROS, reactive oxygen species; SAC, S-allyl-L-cysteine; Ses, sesamin; SFN, DL-sulforaphane.

Abstract

Mitochondrial impairment and the resulting generation of reactive oxygen species (ROS) have been associated with aging and its related pathological conditions. Recently, dietary antioxidants have gained significant attention as potential preventive and therapeutic agents against ROS-generated aging and pathological conditions. We previously demonstrated that food-derived antioxidants prevented intracellular oxidative stress under proteasome inhibition conditions, which was attributed to mitochondrial dysfunction and ROS generation, followed by cell death. Here, we further screened dietary antioxidants for their activity as redox modulators by visualization of the redox state using Redoxfluor, a fluorescent protein redox probe. Direct alleviation of ROS by antioxidants, but not induction of antioxidative enzymes, prevented mitochondria-mediated intracellular oxidation. The effective antioxidants scavenged mitochondrial ROS and suppressed cell death. Our study indicates that redox visualization under mitochondria-mediated oxidative stress is useful for screening potential antioxidants to counteract mitochondrial dysfunction, which has been implicated in aging and the pathogenesis of aging-related diseases.

Graphical abstract

Direct alleviation of mitochondrial impairment-producing ROS by dietary antioxidants maintained intracellular redox state and improved cell viability.

Key words:

• dietary antioxidant
• mitochondria
• reactive oxygen species
• redox visualization
• screening method

Acknowledgment

We thank Dr. Shinyo Gayama (Mitsubishi Gas Chemical Company) for kind gifts of PQQ and Bio-PQQ™.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

Abbreviations: ALA, (±)-α-lipoic acid; α-toco, DL-α-tocopherol; Bio-PQQ™, pyrroloquinoline quinone disodium salt; CHO, chinese hamster ovary; ETC, electron transport chain; FRET, fluorescence resonance energy transfer; GSTA2, glutathione S-transferase A2; HO-1, heme oxygenase-1; Lyc, lycopene; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; Nrf2, nuclear factor erythroid-2-related factor 2; PQQ, pyrroloquinoline quinone; Res, resveratrol; ROS, reactive oxygen species; SAC, S-allyl-L-cysteine; Ses, sesamin; SFN, DL-sulforaphane.