Discovery of the mechanisms and major bioactive compounds responsible for the protective effects of Gualou Xiebai Decoction on coronary heart disease by network pharmacology analysis

Background: Gualou Xiebai decoction (GLXB), a multi-component herbal formula, has been widely used to treat coronary heart disease (CHD) in China for centuries. Several studies have revealed part of its pharmacological activities, whereas its active compounds and mechanisms of action are still unknown because of its complex composition. Purpose: Discover the major active compounds and the pharmacological mechanisms of GLXB by network pharmacology methods. Methods: The main candidate target network was constructed by predicting targets of absorbable chemical compounds of GLXB, collecting therapeutic targets of cardiovascular drugs, constructing target network and layers of screening. Community detection and edge-betweenness calculation were applied to analyze the main candidate target network. Cell viability test, Western blot and flow cytometry were performed to validate the predicted results in cardiomyocytes hypoxia/reoxygenation model. Results: Five clusters and eight cross-talk targets were found in the main candidate target network. Their functions combined together might explain the multifunctional role of GLXB against CHD. Among the cross-talk targets, ESR1 (Estrogen receptor alpha, ERa) and MAPK14 (Mitogen-activated protein kinase 14, p38) were both drug targets and therapeutic targets whose interaction exhibited the greatest edge-betweenness value, suggesting their crucial role in the protective effect of GLXB. The compounds targeting on ESR1 and MAPK14 were identified as apigenin and 25S-macrostemonoside P respectively which were regard as the major bioactive compounds. The predicted results including the major bioactive compounds, their targets and the synergic effects between them were validated. Conclusion: This study screened out major bioactive compounds from GLXB and offered a new understanding of the protection mechanism of GLXB against CHD by network pharmacology method and provides a combination strategy to explore mechanisms of action of multi-component drugs from a holistic perspective.