Potential cardiotoxic components of Tripterygium wilfordii Hook. f. prediction and verification through cardiac ion channel proteins

Tripterygium wilfordii Hook. f. has been widely used in clinical practice due to its good anti-inflammatory and analgesic activities. However, the application is limited by some potential toxicity and side effects. Therefore, this study aimed to explore the potential heart risk components and potential mechanism of Tripterygium wilfordii. Traditional Chinese Medicine Database and Analysis Platform (TCMSP), Swiss Target Prediction, GeneCards and Open Target Platform databases were used to obtain the potential targets of Tripterygium wilfordii monomers and arrhythmia. GO pathway enrichment analysis was performed by Sangerbox. The potential interaction between monomers and hNav1.5 and hERG (two subtypes of ion channel protein) were predicted by AutoDock and verified by using whole cell patch clamp recordings. Intracellular calcium concentration of H9c2 myocardial cells were tested Fura2-AM fluorescence probe. Acute toxicity tests in mice were used to verify the potential cardiac risk in vivo through heart rate and representative cardiac enzyme profile. The results showed that 38 kinds of Tripterygium wilfordii components were screened by TCMSP, among them, 17 terpenoid monomer structures were acquired through PubChem database. 119 genes associated with disease and monomers were also obtained through various databases, and GO function analysis suggested that ion channels are probably target types of cardiac risk. The molecular docking results showed that 17 components could bind with hNav1.5 and hERG with different binding energy. Patch clamp results showed that mairin and wilforlide A could significantly inhibit the peak current of both hNav1.5and hERG and affect the dynamic property of both channels. Furthermore, mairin and wilforlide A could inhibit cell viability and increase intracellular calcium concentration of H9c2 myocardial cells, and mairin inhibited the heart rate ratio and increased the level of CK-MB. In conclusion, ion channel might be the potential cardiac risk target of Tripterygium wilfordii terpenoid, and mairin and wilforlide A might be main components of Tripterygium wilfordii causing cardiac risk.