Network pharmacology studies on the effect of Chai-Ling decoction in coronavirus disease 2019

Background: Chai-Ling decoction (CLD), derived from a modification of Xiao-Chai-Hu (XCH) decoction and Wu-Ling-San (WLS) decoction, has been used to treat the early-stage of coronavirus disease 2019 (COVID-19). However, the mechanisms of CLD in COVID-19 remain unknown. In this study, the potential mechanisms of CLD in COVID-19 were preliminarily investigated based on network pharmacology and molecular docking method. Methods: Initially, the active components and targets of CLD were screened based on Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and PharmMapper database. The targets of COVID-19 were obtained from GeneCards database. The protein-protein interaction network was established using STRING database to analyze the key targets. Gene Oncology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes analysis were also conducted to evaluate the pathways related to the targets of CLD on COVID-19. Moreover, the compound-target-pathway network was established using Cytoscape 3.2.7. Subsequently, the molecular docking method was performed to select the active compounds with high binding affinity on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and angiotensin-converting enzyme 2 (ACE2), which is the key target of SARS-CoV-2 in entering target cells. The possible binding sites were also visualized by a three-dimensional graph. Results: Network pharmacology analysis showed that there were 106 active components and 160 targets of CLD. Additionally, 251 targets related to COVID-19 were identified, and 24 candidates of CLD on COVID-19 were selected. A total of 283 GO terms of CLD on COVID-19 were identified, and 181 pathways were screened based on GO and Kyoto Encyclopedia of Genes and Genomes analyses. CLD might alleviate the inflammatory response and improve lung injury to treat COVID-19 through interleukin 17 signaling, T helper cell 17 differentiation, tumor necrosis factor signaling, and hypoxia inducible factor-1 signaling. Besides, molecular docking indicated that beta-sitosterol, kaempferol, and stigmasterol were the top three candidates in CLD with the highest affinity to SARS-CoV-2 and ACE2. Conclusion: Our study identifies the potential mechanisms of CLD on COVID-19 and beta-sitosterol, kaempferol, and stigmasterol may be the key compounds that exert antiviral effects against SARS-CoV-2.