Inhibition of mitochondrial respiration and production of toxic oxygen radicals by flavonoids

Antioxidants and polyunsaturated fatty acids in multiple sclerosis

“…Luteolin and quercetin belong to the flavone and flavonol group, respectively, and both prevent H 2 O 2 -induced oxidative stress in oligodendroglia (van Meeteren et al, 2004). Some flavonoids, for example, quercetin, can redoxcycle (Hodnick et al, 1986) and have been shown to be pro-oxidants by the reduction of Fe 3 þ (Canada et al, 1990). This renders these compounds less suitable for therapeutical application (van Acker et al, 1996).…”

trans-Resveratrol induces apoptosis in human breast cancer cells MCF-7 by the activation of MAP kinases pathways

“…It has been also demonstrated that, under the phenoxyl radical form, polyphenols can cause mitochondrial toxicity by collapsing the mitochondrial transmembrane potential, thereby allowing ROS being generated at high extent [19]. Moreover it has been reported that several natural-occurring flavonoids, and trans-resveratrol itself, are able to affect mitochondrial respiration [24] by inhibiting NADH oxidase, succinoxidase and ATP synthesis [3], thus inducing the generation of partially reduced oxygen species [26,48]. Particularly, a direct relationship between flavonoids redox potential and the above mentioned mitochondrial phenomena, has been proposed [25].…”

“…An intimate relationship between ROS and activation of phosphorylative cascades in the apoptotic response downstream polyphenols treatment has been argued [52] and, especially for what trans-resveratrol concerns, several pathways involving MAP kinases have been proposed to be activated upon pharmaceutical (micromolar) doses, as modulators of apoptosis [24]. Therefore, in this study, we have focused on the role of oxidative stress and oxidative stress-induced MAPK as downstream effectors of high (pharmaceutical) doses of trans-resveratrol.…”

Polyphenols as Adaptogens – The Real Mechanism of the Antioxidant Effect?

“…It has been shown, in vitro, that flavonoids can inhibit specific mitochondrial functions, including NADH oxidase (Hodnick et al, 1986), F1-ATPase (Gledhill et al, 2007) and the membrane permeability transition (Santos et al, 1998). Other in vitro studies found that polyphenols inhibited overall mitochondrial respiration (Hodnick et al, 1987) and the closely related rate of ATP generation (Dorta et al, 2005).…”