Andrographis paniculata Nees is an official herbal medicine for treatment of infection and inflammation in China. Andrograpanin, the one of diterpene lactones in A. paniculata, is a hydrolysate from neoandrographolide in vivo and in vitro. The goal of the present study was to investigate andrograpanin which effects on over production of nitric oxide (NO) and pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-12p70) and the key signaling pathways involved in lipopolysaccharide (LPS)-activated macrophage cells. The results showed that NO and all three pro-inflammatory cytokines were inhibited by andrograpanin (15-90 microM) in a dose-dependent manner. The RT-PCR and western blotting assays showed that andrograpanin inhibited productions of NO and pro-inflammatory cytokines through down-regulating iNOS and pro-inflammatory cytokines gene expression levels. Further studies suggested that down-regulation of p38 mitogen-activated protein kinase (MAPKs) signaling pathways were involved in the anti-inflammatory activities of andrograpanin. This study provided evidences that andrograpanin might be useful as a potential anti-inflammatory leading compound for inflammatory drug development.