In Vitro and In Vivo Anti-Inflammatory Effects of Polyphyllin VII through Downregulating MAPK and NF-κB Pathways

Background: Polyphyllin VII (PP7), a steroidal saponin from Paris polyphylla, has been found to exert strong anticancer activity. Little is known about the anti-inflammatory property of PP7. In this study, the anti-inflammatory activity and its underlying mechanisms of PP7 were evaluated in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and in multiple animal models. Methods: The content of nitric oxide (NO) was determined by spectrophotometry. The levels of prostaglandin E2 (PGE₂) and cytokines were measured by enzyme-linked immunosorbent assay (ELISA) assay. The mRNA expression of pro-inflammatory genes was determined by qPCR. The total and phosphorylated protein levels were examined by Western blotting. The in vivo anti-inflammatory activities were evaluated by using mouse and zebrafish models. Results: PP7 reduced the production of NO and PGE₂ and the protein and mRNA expressions of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and enzymes (inducible NO synthase [iNOS], cyclooxygenase-2 [COX-2], and Matrix metalloproteinase-9 [MMP-9]) in LPS-induced RAW264.7 cells by suppressing the NF-κB and MAPKs pathways. Notably, PP7 markedly inhibited xylene-induced ear edema and cotton pellet-induced granuloma formation in mice and suppressed LPS and CuSO₄-induced inflammation and toxicity in zebrafish embryos. Conclusion: This study demonstrates that PP7 exerts strong anti-inflammatory activities in multiple in vitro and in vivo models and suggests that PP7 is a potential novel therapeutic agent for inflammatory diseases.