20( S )-Protopanaxadiol Targets HMGB1 to Inhibit Inflammasome Activation and Ameliorate Acute Lung Injury

Abstract 20(S)-Protopanaxadiol (PPD), a major intestinal metabolite of ginsenosides from Panax ginseng, possesses anti-inflammatory properties, yet its direct molecular targets are poorly defined. This study investigated the protective effects of PPD against acute lung injury (ALI) and its potential mechanism. Using LPS-challenged immortalized mouse bone-marrow-derived macrophages (iBMDMs) and ALI mouse models, limited proteolysis–mass spectrometry identified HMGB1 as the primary binding target. PPD blocked inflammasome activation and interrupted HMGB1–TLR4 interaction. Molecular docking, dynamics simulations, and site mutagenesis verified that PPD stably binds the HMGB1 B-box domain. In vivo, PPD mitigated pulmonary damage, alleviated alveolar edema and inflammatory infiltration, lowered proinflammatory cytokines, and restrained HMGB1 secretion. In conclusion, PPD directly targets HMGB1 to block HMGB1–TLR4 inflammatory signaling. These data suggest PPD can serve as a promising functional food constituent for ALI prevention.