Fucoxanthin Attenuates Myocardial Ischemia/Reperfusion‐Induced Injury via <scp>AMPK</scp>/<scp>GSK</scp>‐3β/Nrf2 Axis

Fucoxanthin (Fx), a xanthophyll carotenoid abundant in brown algae, possesses several biological functions, such as antioxidant, anti-inflammatory, and cardiac-protective activities. However, the role of Fx in myocardial ischemia/reperfusion (MI/R) is still unclear. Thus, the aim of this study was to investigate the effect of Fx on MI/R-induced injury and explore the underlying mechanisms. Our results showed that in vitro, Fx treatment significantly suppressed inflammatory response, oxidative stress, and apoptosis in rat cardiomyocytes exposed to hypoxia/reoxygenation (H/R). In addition, Fx led to increased phosphorylation of AMPK, AKT, and GSK-3β, and enhanced activation of Nrf2 in cardiomyocytes under H/R conditions. Notably, pretreatment with Compound C (AMPK inhibitor), partially reduced the beneficial effects of Fx in cardiomyocytes exposed to H/R. In vivo, Fx ameliorated myocardial damage, inhibited inflammatory response, oxidative stress, and apoptosis, and activated the AMPK/GSK-3β/Nrf2 signaling in myocardial tissues in MI/R rat model. Taken together, these findings indicated that Fx attenuates MI/R-induced injury by inhibiting oxidative stress, inflammatory response, and apoptosis. The AMPK/GSK-3β/Nrf2 pathway is involved in the cardioprotective effect of Fx in MI/R injury. Thus, Fx may be a promising drug for the treatment of MI/R.