Protective effects and regulatory mechanisms of Platycodin D against LPS-Induced inflammatory injury in BEAS-2B cells

Platycodin D (PLD), a major bioactive component of triterpene saponins found in Platycodon grandiflora, is renowned for its anti-inflammatory and antioxidant properties. This study aims to explore the protective effects and regulatory mechanisms of PLD in an LPS-induced inflammation injury model of BEAS-2B cells. Initially, PLD was identified from Platycodon grandiflora extracts utilizing UPLC-Q-TOF-MS/MS technology. The effects of PLD on the viability, morphology, ROS levels, and inflammatory factors of LPS-induced BEAS-2B cells were then investigated. The results showed that PLD significantly alleviated LPS-induced oxidative stress and inflammatory injury. Further analysis revealed that PLD positively influenced apoptosis levels, mitochondrial morphology, and related gene expression, indicating its potential to mitigate LPS-induced apoptosis and alleviate mitochondrial dysfunction. Using molecular docking technology, we predicted the binding sites of PLD with mitochondrial autophagy protein. Gene expression levels of autophagy-related proteins were measured to determine the impact of PLD on mitochondrial autophagy. Additionally, the study examined whether the mitochondrial autophagy agonists rapamycin (RAPA) could modulate the upregulation of inflammasome-related factors NLRP3 and Caspase-1 in LPS-induced BEAS-2B cells. This was done to evaluate the regulator mechanisms of PLD in pulmonary inflammatory injury. Our findings suggest that PLD's mechanism of action involves the regulation of mitochondrial autophagy, which in turn modulates inflammatory responses.