Hydroxytyrosol and Brain Tumors: Mechanisms of Action and Therapeutic Potential.

Central nervous system (CNS) tumors, especially gliomas and IDH-wildtype glioblastoma, present high aggressiveness, low response to current treatments and limited survival. Several biological processes such as oxidative stress, inflammation, apoptosis, and autophagy are involved in their development. Hydroxytyrosol (HTX), a phenolic compound present in olives, has shown relevant effects on these processes in experimental models. This review analyzes its chemical characteristics, bioavailability, and ability to cross the blood-brain barrier, as well as its mechanisms of action. Despite its rapid metabolism, HTX can reach the brain in small but functional amounts, and various formulation methods can enhance its delivery to nervous tissue. HTX acts on cellular pathways such as Nrf2, NF-κB, JAK/STAT, PI3K/Akt and SIRT1, regulating redox balance, inflammation, programmed cell death, and autophagy. It can also influence gene expression through epigenetic mechanisms. In cell models, it has shown inhibitory effects on tumor growth and activation of apoptosis, without affecting non-tumor cells. These results support its possible usefulness as an adjunct in the treatment of brain tumors, although further studies in animal and human models are required.