Network pharmacology-based approach to evaluate the effect and predict the mechanism of Calculus bovis against oral ulcers

Calculus bovis (CB), a famous traditional Chinese medicine, is commonly used to treat various inflammatory diseases, including oral ulcers. However, the potential mechanisms of CB in the treatment of oral ulcers are still limited. The present study aimed to use a network pharmacology-based approach to understand the multi-compound, multi-target, multi-pathway effect of CB against oral ulcers. The network pharmacology included the following main parts: first, we screened bioactive compounds and predicted corresponding targets via multiple databases; second, we used R software to analyze related Gene Ontology (GO) and KEGG terms; third, we calculated the network proximity on the protein–protein interaction background and identified potential modules. Finally, a rat oral ulcer model was used to validate the therapeutic effect of CB against oral ulcers and test the expression of important targets. Through network pharmacology analysis, 12 bioactive compounds were initially screened out. The network proximity Z score was -4.37, indicating the potential therapeutic efficacy of CB against oral ulcers. Six potential modules were identified, while module 1 was related to the NOD-like receptor signaling pathway and module 6 was related to apoptosis. Experiments confirmed the therapeutic efficacy of CB against oral ulcers. Western blotting indicated that CB upregulated the anti-apoptosis protein Bcl-xl and downregulated the pro-apoptosis protein Bax and the nlrp3 signal. In conclusion, CB exerted a curative effect on oral ulcers by inhibiting apoptosis and nlrp3 activation.