BU extracts suppressed IL-1 expression with a low cytotoxicity. M1-polarized RAW264.7 was treated graded levels of BU extracts for 24 h. A. Real-time PCR evaluation of IL-1 mRNA expression in M1-polarized RAW264.7. RAW264.7 without treatment was used as the additional controls. *p < 0.01 and **P < 0.01 versus RAW264.7 without treatment, while #p < 0.05 and ##p < 0.01 versus M1-polarized RAW264.7 without treatment. B. The cytotoxicity of BU extracts was determined by MTS assay, and the results were presented as% of controls. Data are expressed as mean ± SD of three independent experiments done in triplicate.