Honokiol post-treatment ameliorates myocardial ischemia/reperfusion injury by enhancing autophagic flux and reducing intracellular ROS production.

Honokiol (HKL) is a natural low-molecular-weight biphenolic compound derived from the bark of magnolia trees. Previous studies indicate that HKL exerts potent cardioprotective effects on ischemia/reperfusion (I/R) injury; however, evidence of the further relationship between HKL posttreatment and myocardial I/R injury has not been clearly found. In our study, we explored the protective effect of HKL post treatment on myocardial I/R injury in C57BL/6 mice. We also demonstrated that HKL significantly reduced cellular reactive oxygen species production and attenuated mitochondrial damage in neonatal rat cardiomyocytes exposed to hypoxia/reoxygenation (H/R). In addition, HKL was found to enhance autophagy during I/R or H/R; these effects could be partially blocked by the autophagic flux inhibitor chloroquine. Moreover, our results suggested that enhanced autophagic flux is associated with the Akt signaling pathway. Collectively, our results indicate that HKL posttreatment alleviates myocardial I/R injury and suggest a critical cardioprotective role of HKL in promoting autophagic flux.