Myocardial IRI (MIRI) is a severe pathophysiological condition associated with complex mechanisms, including oxidative stress, cell apoptosis, and inflammatory responses
[5][6][7]. Overproduction of ROS activates various molecular cascades of apoptosis
[8][9]. Furthermore, inhibition of ROS production or free radicals scavenging is suggested as potential therapeutic strategies to attenuate IRI
[2][70]. Nrf2 signaling is associated with the cleavage process during MIRI, as Nrf2 disassociates from Keap1, translocates to the nucleus where it binds to AREs, and regulates target genes’ expressions during oxidative stress
[71][72]. The Nrf2 signaling pathway reportedly protects against anoxia/reoxygenation-induced apoptosis
[62].
Zhang et al.
[73] suggested that melatonin may protect H9c2 cells against IRI by reducing apoptosis and oxidative stress, mediated via activation of the Nrf2 signaling pathway. The protective effect of atorvastatin is generated via the inhibition of neutrophil infiltration, TNF-α production, and activation of the Nrf2/ARE pathway, leading to upregulation of HO-1, a sensitive and reliable indicator of cellular oxidative stress
[74]. L-carnitine can reduce MIRI via activating the Nrf2/HO-1 signaling pathway and reducing oxidative stress and apoptosis in cardiomyocytes. Zhao et al.
[75] reported the significant escalation of the Nrf2/HO-1 signaling pathway in myocardial tissue in L-carnitine-injected rats, which indicates that L-carnitine activates the Nrf2/HO-1 signaling pathway and reduces oxidative stress in cardiomyocytes. The bardoxolone derivative, DH404, showed protective effects against infarct expansion and remodeling post-MI in rats by re-coupling eNOS and increasing the functional interaction of Grx1 eNOS, and activates Nrf2
[76].
Plant polyphenols, such as flavonoids, chalcones, triterpenes, and proanthocyanidins, have cardioprotective, antiapoptotic, and anti-ischemic properties, which cause a decrease in the infarct size, arrhythmia score, and improvement in cardiac stunning primarily via the release of NO, the activation of the Nrf2 pathway and endogenous antioxidant defense system
[77]. Resveratrol, the polyphenolic compound present in red grapes and wine, ameliorates cardiac dysfunction induced by MI/R by activating the Nrf2/ARE pathway and increases the expression of Nrf2 by inducing SIRT1 or inhibiting GSK3β, thus alleviating myocardial oxidative stress, and thereby improving IRI
[78][79]. It was suggested that through the activation of PI3K/Akt/p38 MAPK, H
2O
2 preconditioning alleviate the caspase-3 activity, increases the expression of Bcl2, and leads to the translocation of Nrf2 into the nucleus, which selectively increases the expression and activity of antioxidant enzymes to prevent MIRI-induced apoptosis
[65]. Triptolide, the bioactive component present in
Tripterygium wilfordii Hook F, reportedly reduces I/R-induced myocardial infarction, inflammation, oxidative stress and improves the cardiac function in rats via its effect on the Nrf2/HO-1 defense pathway
[80]. Aloin, the major bioactive anthraquinone of the Aloe species, also diminishes I/R-induced oxidative stress injury and inflammatory response in cardiomyocytes by activating the Nrf2-HO-1 signaling
[81]. Recent studies indicated that garlic (
Allium sativum) and its constituents, such as Allicin and Diallyl sulfide, were reported to activate Nrf2 and increase HO-1 and NQO1 expression through ERK/p38 signaling pathway activation, thus playing a protective role in the adaptation of diabetic cardiomyopathy
[82]. Another polyphenolic compound, luteolin, contained in vegetables, was shown to protect the diabetic heart against IRI by enhancing eNOS-mediated S-nitrosylation of Keap1, with subsequent upregulation of Nrf2 and the Nrf2-related antioxidative signaling pathway
[83]. New curcumin analog, 14p, decreased oxidative stress and reduced MIRI via increasing Nrf2 expression
[72]. Kaempferide (3,5,7-trihydroxy-4-methoxy flavone) inhibits Nrf2 and cleaved caspase-3 signaling pathways through a PI3K/Akt/GSK 3β-dependent mechanism and attenuates I/R-induced myocardial injury
[84] (). Simultaneously, Butin, a plant dietary flavonoid, protects against I/R-induced ROS-mediated apoptosis by upregulating the AMPK/Akt/GSK-3β pathway and activates Nrf2-regulated antioxidant enzymes in diabetic cardiomyocytes exposed to I/R
[85]. Crocin, the active component of saffron, suppresses I/R-induced cardiomyocyte apoptosis via ER stress inhibition by modulating the miR-34a/Sirt1/Nrf2 signaling pathway
[86]. Hyperoside, a flavonoid isolated from Rhododendron ponticum L., was suggested to have a protective effect on cardiac IRI by inhibiting ER stress and activating the Nrf2 signaling pathway in an ischemia/reperfusion animal model
[87]. Soybean isoflavones are shown to activate Nrf2-mediated antioxidant responses in a dose-dependent way and alleviate ischemic cardiomyopathy
[88].