The pistil of nelumbo nucifera has anti-inflammatory effect in LPS-activated Raw 264.7 cells

The pistil of nelumbo nucifera (PNN) is used in the treatment of nocturnal pollution, hematemesis, epistaxis, metrorrhagia and diarrhoea in traditional medicine. The present study was examined to evaluate the effects of PNN on the production of pro-inflammatory mediators in vitro. After the treatment of PNN, cell viability was measured by MTT assay, nitric oxide (NO) production was monitored by measuring the nitrite content in culture medium. The protein bands were determined by immunoblot analysis and levels of cytokines were analyzed by sandwich immunoassays. In the MTT assay, the doses of PNN extract (0.03, 0.10 mg/ml) had no significant cytotoxicity. The increases of NO production and inducible nitric oxide synthase expression were detected in lipopolysaccharide(LPS)-activated Raw 264.7 cells compared with control, in contrast, these increases were significantly attenuated by pre-treatment with PNN. In cytokine assay, the massive pro-inflammatory cytokines such as tumour necrosis factor-, interleukin (IL)- and IL-6 were induced in LPS-activated Raw 264.7 cells, but pre-treatment of Raw 264.7 cells with PNN caused inhibition (TNF-=14.17%, IL-=107.43%, IL-6=46.27%) the production of cytokines by LPS. In addition, PNN reduced prostaglandin E2 productions in a dose-dependent manner (0.03mg/ml=37.52%, 0.10 mg/ml=83.77%) as a consequence of the inhibition of cyclooxygenase-2 expression. Taken together, our data indicates that PNN can regulate the inflammatory response in macrophage cells activated by Gram-negative infection.