Revealing the “Yin-Jing” mystery veil of Platycodon grandiflorum by potentiating therapeutic effects and lung-oriented guidance property

"Yin-Jing" medicine (YJM) has been widely used by both ancient and modern Chinese medicine practitioners during long-term clinical practice. However, it remains unclear how to best guide other medicines to the targeted organs in a traditional Chinese medicine (TCM) prescription. Here, in an attempt to explain the scientific connotation of the YJM property (YJMP) attributed to a basic TCM theory, Platycodon grandiflorum (PG) was chosen as a case study to reveal the mystery of YJMP theory. The main purpose of this study is to employ modern chemical and molecular biology methods to confirm the "Yin-Jing" effect of PG, and further clarify its material basis and related possible mechanism. The ammonia-induced lung injury rat model was utilized to determine the optimal dosage of traditional prescription Hui Yan Zhu Yu decoction (HYZYD) using Wright Giemsa staining, HE staining, masson staining and TUNEL analysis. With the same way, PG was confirmed to have potentiating therapeutic effect (PTE) by comparison with HYZYD and [HYZYD-PG]. TMT proteomics was used to reveal the "Yin-Jing" mechanism of action. Western blot assay (WB) was employed for verification of differentially expressed proteins. Additionally, four non-crossing fragmentations (Fr. A-D) were characterized by RPLC/SEC-ELSD and HILIC-ESI–-Q-OT-IT-MS techniques. The PTE and guidance property assays were utilized to evaluate "Yin-Jing" functions by compatible combination of hydroxysafflor yellow A (HYA) using qPCR, FCM, WB, HPLC, high content cell imaging (HCI) and high-resolution live-cell imaging (HRLCI) techniques. The HYZYD-M (medium dose group) significantly improved the lung injury level in a pneumonia model of rats. PG enhanced the therapeutic effect of HYZYD ascribed to Yin-Jing PTE functions. TMT proteomics revealed a category of differentially expressed proteins ascribed to Golgi-ER between HYZYD and [HYZYD-PG]. Fr. C (i.e., saponins) and Fr. D (i.e., lipids) were determined as therapeutic fragmentations via LPS-induced A549 cell injury model; however, Fr. B (fructooligosaccharides and small Mw fructans) had no therapeutic effect. Further compatibility PTE assays confirmed Fr. B significantly improved efficiency by a combination of HYA. The guidance assays showed Fr. B could significantly increase the uptake and distribution of HYA into lung cells and tissues. HCI assays showed that Fr. B increased uptake of HYA accompanied by significant activation of Golgi-ER. Unlike Fr. B, HRLCI showed that Fr. A, C and D were not only unobvious activations of Golgi-ER but also insignificant facilitations of colocalizations between HYA and Golgi-ER. Fr. B is believed to be a key YJMP material basis of PG attributed to Yin-Jing PTE with characteristic of lung-oriented guidance property, whereas another abound Fr. C was determined to have synergistic effects rather than Yin-Jing material basis.