Sodium New Houttuyfonate Effectively Improves Phagocytosis and Inhibits the Excessive Release of Inflammatory Factors by Repressing TLR4/NF-ΚB Pathway in Macrophages

Background: Sodium new houttuyfonate (SNH) is an adduct of houttuyfonate, which is the main component of the common Chinese medicinal plant Houttuynia cordata. SNH has been widely used in antibacterial and anti-inflammatory treatments in clinics. However, the exact antimicrobial mechanism of SNH is still unclear, despite its mild direct antimicrobial activity in vitro. Objectives: The aim of this study is to investigate the effect and possible mechanism of SNH on macrophages against bacteria in vitro. Methods: In this study, we assessed the antibacterial and anti-inflammatory effects of SNH on the RAW264.7 macrophage cell line against Pseudomonas aeruginosa, a major opportunistic pathogen. Results: Firstly, we found that SNH showed minimal toxicity on RAW264.7 macrophages. Secondly, our results indicated that SNH effectively inhibited the inflammatory reaction of macrophages stimulated by P. aeruginosa. We also found that SNH improved the phagocytosis and killing effect of RAW264.7 macrophages against P. aeruginosa in vitro. Furthermore, our results revealed that SNH effectively inhibited the expression of the TLR4/NF-ΚB pathway in macrophage RAW264.7 co-incubated with P. aeruginosa in vitro. Conclusion: Based on our findings, SNH can significantly improve the phagocytosis of macrophages and inhibit the excessive release of inflammatory factors by repressing the TLR4/NF-ΚB pathway.