Ethnopharmacological relevance: Platycodon grandiflorus (Jacq.) A.DC. (PG) is a common natural medicine with a history of thousands of years. The processing products were mainly recorded as raw, honey-processed, wine-fried, yellow-fried, and bran-fried PG, which were respectively used for different clinical purposes. Therefore, it is necessary to study the chemical composition and pharmacological activity of PG after processing.
Aim of the study: To explore the effects of different processing methods on the composition and biological activity of PG using metabonomics and pharmacologic design.
Materials and methods: UPLC-QTOF-MS combined with multivariate statistical analysis was used to identify different metabolites before and after the processing of PG. Network pharmacology was used to construct the metabolite-target-disease network. CCK-8 assay, flow cytometry, and western blotting were used to detect cell viability, apoptosis, and the expression of related proteins, respectively.
Result: A total of 43 differentially expressed metabolites (VIP >10) were detected and identified in the analyzed groups. Based on their chemical nature, these metabolites were divided into five categories, namely, saccharolipids, flavonoid glycosides, alkynes, saponins, and lipids (including fatty acids, phospholipids, fatty aldehydes, and sterols). The content of lipids in the five processed groups (CH, FC, JZ, MZI, and MZG) was found to be higher than that in raw PG. In particular, the processing approaches explored herein increased the contents of many phospholipids, such as, glycerophosphoinositols, phosphatidic acids, and lysophosphatidyle·thanolamines. The 8 metabolites were found by venn diagram to distinguish different processed products (metabolites 2, 6, 19, 20, 21, 26, 28, and 38). The results of network pharmacology analysis showed that the primary anti-cancer targets of 43 metabolites of PG processing products are PIK3CA, Akt, and STAT3, and based on CCK-8 assay, MZI has a significant killing effect on A549 cells, compared to other processing techniques. Moreover, flow cytometry analysis showed that the cells treated with MZI exhibit significantly increased cell apoptosis, and that the effect is dose-dependent. Finally, the western blots performed herein demonstrated that the MZI effectively inhibits the expression of p-Akt and p-STAT3, which is consistent with the network pharmacology results.
Conclusion: Depending on the processing technique, the contents of 43 different metabolites in PG were varied significantly. Specifically, the contents of phospholipids and fatty acids increase, whereas the contents of large Mw saponins decrease. Compared to the other investigated processing methods, MZI increases the potential of PG in inducing cell apoptosis and inhibiting cell proliferation by affecting the Akt and STAT3 signaling pathways. The increased levels of 3-O-β-glucopyranosyl polygalacic acid and platycoside F after honey-frying confirm these results.
Keywords: A549 cells; Anti-cancer; Metabolite; Network pharmacology and validation; Platycodon grandiflorum; UPLC-QTOF-MS.
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