Elucidating the anti-inflammatory activity of platycodins in lung inflammation through pulmonary distribution dynamics and grey relational analysis of cytokines

Platycodonis Radix (PR) is a traditional herbal remedy used to prevent and treat lung inflammation, and platycodins are speculated to be the major active constituents. However, concrete experimental verification for this assertion remains absent thus far. This study aims to compare the pulmonary distribution dynamics of five platycodins and analyze their effects on cytokines. Through the grey relational analysis (GRA) between pulmonary active components and cytokines, the study ascertains platycodins as the potential effective component against lung inflammation. A rat lung inflammation model was created using lipopolysaccharides (LPS). Pulmonary distribution dynamics were analyzed via LC-MS/MS. Cytokine changes and distribution patterns in lung tissues were studied by multi-factor reagent kit. GRA was applied to determine correlations between pulmonary components and cytokines. Finally, the anti-inflammatory properties of platycodins were further studied using LPS-induced BEAS-2B cells in vitro. The results showed that five platycodins (Platycodin D, Platycodin D3, Deapio Platycodin D, 3-O-β-D-Glucopyranosyl Platycodigenin, and Platycodigenin) featured fast absorption rate, short time to peak, and slow metabolism rate. The pulmonary distribution dynamics were significantly affected within 2 h after LPS modeling. At the same time, PR altered the relationships among different cytokines induced by LPS stimulation, particularly inflammatory cytokines IL-6 and IFN-γ. The GRA results indicated good correlation between the pulmonary distribution dynamics of the five platycodins components and the changing patterns of cytokine levels, with Platycodin D3 contributing the most. Additionally, Platycodin D3 exhibited a protective role against LPS-induced inflammation by reducing the production of pro-inflammatory mediators such as IL-1β, IL-8, and ROS, as well as increasing the expression of the anti-inflammatory mediator IL-10. Platycodins are the main anti-inflammatory agents in PR and there is a good correlation with cytokines. This contributes to the anti-pneumonia effect of PR.