Enhanced Stability of α-Mangostin-Rich Extract and Selective Cytotoxicity against Cancer Cells via Encapsulation in Antioxidant Nanoparticles (AME@Nano^AOX)

α-Mangostin-rich extract (AME) shows promise as a functional ingredient for cancer chemotherapy. Here, we encapsulated AME in our originally designed antioxidant nanoparticles (Nano AOX ) to increase its solubility and prevent oxidative degradation (AME@Nano AOX ). In this study, two types of self-assembled polymers containing nitroxide radicals were engineered. These polymers were self-assembled into nanoscale particles in aqueous media, entrapping AME (abbreviated as AME@Nano AOX (B) and AME@Nano AOX (G)). These formulations considerably improved the stability of AME against oxidative degradation and exhibited different release profiles of α-mangostin under different pH conditions. Furthermore, AME-encapsulated nanoparticles exhibited potent cytotoxicity against various cancer cell lines, including human breast cancer (MCF-7), human lung cancer (A549), human colon cancer (Caco-2), human cervical cancer (HeLa), and human liver cancer (HepG2) cell lines, with minimal cytotoxicity in normal human mammary epithelial cells (hTERT-HME1), thus providing a high selectivity index (SI). These results indicated the promising feature of AME-encapsulated antioxidant nanoparticles (AME@Nano AOX ) for cancer chemotherapy.