Hormetic and Mitochondria-Related Mechanisms of Antioxidant Action of Phytochemicals

Abstract

Antioxidant action to afford a health benefit or increased well-being may not be directly exerted by quick reduction-oxidation (REDOX) reactions between the antioxidant and the pro-oxidant molecules in a living being. Furthermore, not all flavonoids or polyphenols derived from plants are beneficial. This paper aims at discussing the variety of mechanisms underlying the so-called “antioxidant” action. Apart from antioxidant direct mechanisms, indirect ones consisting of fueling and boosting innate detox routes should be considered. One of them, hormesis, involves upregulating enzymes that are needed in innate detox pathways and/or regulating the transcription of the so-called vitagenes. Moreover, there is evidence that some plant-derived compounds may have a direct role in events taking place in mitochondria, which is an organelle prone to oxidative stress if electron transport is faulty. Insights into the potential of molecules able to enter into the electron transport chain would require the determination of their reduction potential. Additionally, it is advisable to know both the oxidized and the reduced structures for each antioxidant candidate. These mechanisms and their related technical developments should help nutraceutical industry to select candidates that are efficacious in physiological conditions to prevent diseases or increase human health.

An Animal Study to Compare Hepatoprotective Effects Between Fermented Rice Bran and Fermented Rice Germ and Soybean in a Sprague-Dawley Rat Model of Alcohol-Induced Hepatic Injury

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Regulation of Nrf2/ARE Pathway by Dietary Flavonoids: A Friend or Foe for Cancer Management?

“…At high concentrations/doses, they may exert either detrimental/inhibitory or toxic effects on the cells or tissue microenvironment [ 64 , 66 , 67 , 68 ]. As such, hormetic compounds act as antioxidants at low doses and prooxidants at high doses [ 13 , 40 , 69 , 70 , 71 ]. For example, apigenin and luteolin at low concentrations (6.25 µM) exert stimulatory effects on the Nrf2/ARE pathway in human hepatocellular carcinoma HepG2 cells, significantly increasing the mRNA and protein expression of Nrf2 and heme oxygenase 1 (HO-1) with the activation of phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) and ERK1/2 signaling [ 65 ].…”

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