MTOR and glioblastoma: Oxymatrine, a naturally occurring antioxidant alkaloid is also known to exhibit a chemopreventive effect against human glioblastoma cells by inducing apoptosis, suppressing invasion, and arresting the cell cycle by suppressing PI3K/Akt/mTOR signaling and downregulating STAT3 and EGFR activation, thereby counteracting with metabolic remodeling in brain cancer cells [251, 257].