A, The cytotoxicity of NCTD is much lower than CTD. RAW264.7 cells were treated with NCTD or CTD for 24 h and cell viability was tested with MTS assay as described under Materials and Methods. B, Cytokines production was enhanced obviously by NCTD in RAW264.7 cells. The RAW264.7 cells were pretreated with PBS (containing 0.1% DMSO) or 1–10 μM NCTD for 24 h before stimulation with 100 ng/ml LPS for 1 h. Total cellular RNA were collected and subjected to Real time -PCR analysis. C, Only LPS induced cytokine production was enhance by NCTD obviously. The RAW264.7 cells were pretreated with 0.1% DMSO, 5 μM NCTD for 24 h before stimulation with LPS (100 ng/ml), PMA (100nM) or LTA (10 µg/ml) for 1 h. Total cellular RNA were collected and subjected to Real time PCR analysis. Columns, mean from three independent experiments with three duplicates; bars, SE (*, P<0.05; **, P<0.01 versus control).