〔Abstract〕 Abstract Objective To explore the effects and mechanisms of Kobophenol A (KPA) on lipopolysaccharide (LPS)-induced M1 macrophage polarization, and to provide a theoretical basis for the treatment of inflammatory immune diseases and the development of new drugs. Methods The M1 macrophage polarization model of RAW264.7 was established by LPS induction, and the Prdx6 knockdown model was constructed using the Prdx6 inhibitor MJ33 and Prdx6-siRNA. RAW264.7 cells, a mouse macrophage cell line, were treated with various concentrations of KPA. Cell viability was assessed using the CCK-8 assay. The expression levels of peroxiredoxin 6 (Prdx6) and M1 macrophage polarization-related proteins, including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), were detected by Western blot and immunofluorescence staining. The expression levels of Prdx6 and M1 macrophage polarization-related genes iNOS, interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α), were measured by RT-qPCR. Flow cytometry was employed to detect the expression of CD86, a marker of M1 macrophages. Results Compared with the LPS-induced M1 macrophage polarization model, KPA significantly reversed the morphological changes of M1 macrophage polarization in RAW264.7 macrophages and decreased the expression of M1 macrophage polarization-related proteins iNOS, COX-2, CD86 and related genes iNOS, IL-6, TNF-α (all P<0.05). In addition, LPS significantly downregulated the expression of Prdx6 in RAW264.7 macrophages, while KPA upregulated the expression of Prdx6. Moreover, treatment with the Prdx6 inhibitor MJ33 significantly upregulated the expression of iNOS, a marker of M1 macrophage polarization, in RAW264.7 macrophages, whereas treatment with KPA significantly downregulated the expression of iNOS (all P<0.05). Conclusion KPA inhibits LPS-induced M1 polarization of RAW264.7 macrophages by upregulating the expression of Prdx6.