Cyclopiazonic Acid Induces Mitochondrial Oxidative Stress in SH-SY5Y Cells: Protective Effects of Extra Virgin Olive Oil Phenolics

Cyclopiazonic acid (CPA), a neurotoxin produced by Penicillium and Aspergillus genera, induces oxidative stress and neuronal damage, mechanisms implicated in neurodegenerative diseases. This study investigates the oxidative stress induced by CPA in SH-SY5Y human neuroblastoma cells, focusing on mitochondrial membrane potential, mitochondrial superoxide levels, ROS production, lipid peroxidation and gene expression. Additionally, the cytoprotective effects of extra virgin olive oil (EVOO) extract, along with its major polyphenols oleuropein (OLE) and tyrosol (TYR), were evaluated. CPA exposure increased mitochondrial superoxide levels and lipid peroxidation, reducing mitochondrial membrane potential, although no intracellular ROS generation was observed. Gene expression analysis revealed downregulation of antioxidant defense genes (nrf2, nos2, ho1, cat, keap1, nqo1, gpx1 and gsr), with the strongest repression observed for nos2 (93%), nqo1 (83%) and ho1 (79%) at the highest CPA concentration, consistent with oxidative stress markers. EVOO extract demonstrated protective effects, enhancing cell viability across all CPA assayed concentrations (400–600 nM). Conversely, TYR and OLE exhibited variable and concentration-dependent effects, also showing protection to a lesser extent, while EVOO extract proved to be more effective due to synergistic interactions among its phenolic components. Overall, CPA induces mitochondrial oxidative damage as a key mechanism of neurotoxicity, while EVOO phenolics mitigate this toxicity.