The present invention provides a composition (e.g., a pharmaceutical composition) for reducing aging-related mitochondrial antioxidant status changes in a subject, wherein the composition comprises Schisandrin B. The present invention further provides a composition (e.g., a pharmaceutical composition) for reducing ischemia-reperfusion injury in an aging subject, wherein the composition comprises Schisandrin B. Also provided are methods for reducing aging-related mitochondrial antioxidant status changes and/or for reducing ischemia-reperfusion injury in an aging subject using the same.