Abstract:An in vitro model of inflammation was established by stimulating the mouse peritoneal macrophage cell line RAW264.7 with lipopolysaccharide (LPS). This model was employed to investigate the anti-inflammatory effects of mulberry extract and the underlying molecular mechanisms. RAW264.7 cells were stimulated with 1 ?g/mL LPS, followed by treatment with different concentrations of the extract. The effect of the extract on RAW264.7 cell viability was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The nitric oxide (NO) and prostaglandin E2 (PGE2) content were determined by the Griess reagent assay and enzyme-linked immunosorbent assay (ELISA), respectively. The expression of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was determined by reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. At the tested concentrations (0.5~2 mg/mL), the mulberry extract did not affect RAW264.7 cell growth. At concentrations ranging from 1 to 2 mg/mL, the extract significantly inhibited NO and PGE2 secretion, as well as iNOS and COX-2 expression. The resveratrol content in the mulberry extract was 107.44±0.48 ?g/g. In conclusion, the results suggest that mulberry extract attenuates LPS-stimulated inflammatory responses and exerts anti-inflammatory effects by suppressing the expression of inflammation-related cytokines; the anti-inflammatory effect of mulberry extract is probably attributable to its high resveratrol content.
