Polysaccharides from Annona Muricata Leaves Protect Against H₂O₂-Induced Oxidative Stress in H9c2 Myoblasts

The purpose of this study was to investigate the antioxidant effects of Annona muricata leaf polysaccharide extract (ALPE) against oxidative stress induced by hydrogen peroxide (H₂O₂) in H9c2 myoblasts. The cells showed a cell viability of around 70% following exposure to 150 μM H₂O₂. In addition, ALPE was noncytotoxic to H9c2 myoblasts at 10-1000 μg/mL concentrations. As confirmed by MTT analysis and Annexin V/propidium iodide staining, ALPE treatment was found to protect H9c2 myoblasts exposed to H₂O₂. This protection is achieved by inhibiting reactive oxygen species levels and inducing superoxide dismutase and catalase activity. Furthermore, ALPE downregulated the activation of Bax, caspase-3, -8, and -9 but upregulated Bcl-2, thereby preventing H₂O₂-stimulated cytotoxicity in H9c2 myoblasts. ALPE activated the Nrf2/heme oxygenase-1 signaling cascade. Collectively, ALPE treatment decreased H₂O₂-induced oxidative stress. Therefore, ALPE can potentially be used as a natural resource with antioxidant properties.