Biological Activities Underlying the Cardiovascular Benefits of Olive Oil Polyphenols: Focus on Antioxidant, Anti-Inflammatory, and Anti-Atherogenic Effects

Extra virgin olive oil (EVOO) polyphenols are recognized for their beneficial effects on human health, yet how their concentration shapes biological outcomes remains insufficiently explored. While a daily intake of 25 mL EVOO is generally regarded as beneficial for cardiovascular protection, the high-phenolic EVOO examined in this study contains markedly higher levels of polyphenols than most EVOOs reported previously. This suggests that oils richer in polyphenols may exert distinct biological effects. To investigate this, we compared extracts from a standard EVOO and a naturally high-phenolic EVOO, along with their key phenolic compounds, hydroxytyrosol (HT) and tyrosol (Tyr). Antioxidant effects were assessed by quantifying intracellular reactive oxygen species (ROS) and lipid peroxidation. Anti-inflammatory activity was evaluated in THP-1-derived macrophages stimulated with LPS by analyzing inflammatory surface markers' expression, cytokines' production, and the NLRP3-inflammasome pathway. Atheroprotective potential was investigated by measuring cholesterol efflux in J774 macrophages. Both EVOO polyphenols extracts and (HT and Tyr) significantly reduced ROS and lipid peroxidation. High phenolic EVOO extract (EVOOPE+) displayed superior antioxidant activity at lower concentrations, while standard EVOO phenolic extract (EVOOPE) showed more consistent effects across doses. Both extracts favored an anti-inflammatory macrophage phenotype, as indicated by increased CD163 and IL-10 expression and reduced CD86, IFN-α, and NLRP3. Moreover, all treatments enhanced cholesterol efflux in a dose-dependent manner, with EVOOPE+ and HT producing the strongest effects. Collectively, these results highlight the capacity of EVOO polyphenols to modulate, through key bioactivity mechanisms, cardioprotective effects and emphasize the importance of polyphenols concentration in their biological efficacy.