Platycodonis Radix (PR), the root of Platycodon grandiflorum (Jacq.), is a traditional herbal medicine used for treating lung and respiratory diseases with over a thousand years of clinical application history (Lee et al., 2004; Li et al., 2022; Zhang et al., 2015). Modern research has demonstrated that PR possesses notable anti-lung inflammation activity, yet the material basis remains uncertain (Choi et al., 2017; Shin and Oh, 2023). Platycodins, characteristic components in PR, include representative compounds such as Platycodin D3, Deapio Platycodin D, and Platycodin D, and might be the potential substance basis for anti-lung inflammation properties of PR (Li et al., 2023).

In general, drugs need to reach specific target organs to exert their therapeutic effects, and determining their anti-inflammatory function solely based on changes in blood drug concentration has certain limitations (Wang et al., 2015). Real-time determination of drug distribution concentration trends in lung tissue under inflammatory conditions, and monitoring distribution patterns of cytokines (inflammation) in the tissue microenvironment can reveal their correlation and provide an effective approach to ascertain the material basis for PR's anti-lung inflammation effects. Grey relational analysis (GRA) is a correlation analysis usually employed to quantitatively compare development trends in dynamic variation systems. Based on the size of the correlation coefficients, the contribution of each compound to the therapeutic effect can be determined (A correlation coefficient above 0.7 indicates a very close relationship; between 0.4 and 0.7 indicates a close relationship; between 0.2 and 0.4 indicates an average relationship) (Deng et al., 2023).

In this study, a LC-MS/MS detection method was established to simultaneously determine five platycodins components in rat lung tissues, and the distribution dynamics of lung tissues in the normal group and inflammation model group were studied. In addition, the correlation between the distribution components in lung tissues and various cytokines (IL-10, IFN-γ, CXCL1, CCL2, GM-CSF, TNF-α, IL-17A, and IL-6) in the model group was also studied, and the potential relationship between PR active components and cytokines was calculated using GRA (Bai et al., 2017). Finally, in vitro validation was conducted using BEAS-2B cells. These results provide a theoretical basis for further revealing the protective mechanism of PR against pneumonia and promoting its clinical application.