Chilean Phaseolus vulgaris landraces: A dietary source influencing NETs formation and phagocytic efficiency

Neutrophil extracellular traps (NETs) are crucial for the antimicrobial defense; however, their dysregulated expression can lead to enhanced inflammation and tissue damage. NET formation requires reactive oxygen species (ROS), particularly those generated through the NADPH oxidase (NOX2) pathway. This study investigates the immunomodulatory effects of aqueous extracts of Chilean landraces of Phaseolus vulgaris L. (Hallado Alemán) with microwave-assisted extraction, on ROS-dependent NETosis and phagocytosis. Using an in vitro model of differentiated HL-60 neutrophil-like cells and human polymorphonuclear neutrophils (PMNs) stimulated with PMA, we evaluated ROS production, NETs release, myeloperoxidase (MPO) activity, and cf-DNA release, as well as phagocytic activity. All experiments were performed in triplicate (n = 3 independent biological replicates); data are presented as mean ± SEM. Both extracts have high polyphenol content and effectively inhibit superoxide production and NET release without cytotoxic effects and increase bacterial phagocytosis. The extract components, including gallic acid, quercetin, and kaempferol, were confirmed by HPLC-DAD. In silico docking analysis showed robust binding of the same polyphenols to key inflammatory-regulating proteins, including PKCb, NOX2, and TLR4/MD2. These findings suggest that aqueous extracts of Phaseolus vulgaris modulate neutrophil function by attenuating proinflammatory responses while preserving antimicrobial activity, indicating their value as natural innate immune modulators.