Abstract: 　Objective　 Objective to study the effect of Radix Paeoniae Rubra extract on Porphyromonas gingivalis (P.g), Fusobacterium nucleatum (F.n) and Actinobacillus actinomycetes (A.a) antibacterial activity of three periodontal pathogenic bacteria, and the potential molecular mechanism and pharmacological activity of Radix Paeoniae Rubra in the prevention and treatment of chronic periodontitis (CP) were studied by network pharmacology method. Methods　 The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of three periodontal pathogens were determined by multiple dilution method. Tcmsp database was used to obtain chemical components and action targets of Radix Paeoniae Rubra, genecards and other databases were used to obtain CP disease targets, and Wayne analysis was used to take intersection. The component-target-disease of Radix Paeoniae Rubra for prevention and treatment of CP was constructed by Cytoscape 3.7.2 software. The protein protein interaction network （PPI network） was constructed by STRING database, and the enrichment analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) was carried out. Results　 The MIC of Radix Paeoniae Rubra extract against P.g, F.n, A.a were 2.0, 4.0 and 4.0 g / L respectively, and MBC were 4.0, 8.0 and 8.0 g / L, respectively. 29 active components, 2132 disease targets and 89 intersection targets were obtained. The main active components of CP treated by Radix Paeoniae Rubra are Baicalin, ellagic acid, and so on. The key targets include Interleukin-6 (IL-6) etc. By GO enrichment analysis, 126 GO items were obtained, such as protein isomerization activity etc. KEGG enrichment analysis showed that there were 110 pathways including mitogen-activated protein kinase (MAPK) signal pathway. Conclusions　 The crude extract of Radix Paeoniae Rubra has different degrees of antibacterial activity against three kinds of periodontal pathogenic bacteria. It is preliminarily expounded that the main active components, action targets and related pathways of Radix Paeoniae Rubra have important research value in the treatment of CP, which provides reference and reference for further expanding the clinical application of Radix Paeoniae Rubra.

Key words: Radix Paeoniae Rubra, chronic periodontitis, antibacterial activity, network pharmacology, action mechanism