Anti-inflammatory activity of extracts from ultra-fine ground saururus chinensis leaves in lipopolysaccharide-stimulated raw 264.7 cells

Bioactive components of ultra-fine ground Saururus, the extraction yield increases when the leaves are ultra-fine ground. Comparison of normal-ground and ultra-fine ground Saururus chinensis leaves showed that the solid content and antiinflammatory activity of ultra-fine ground extracts was higher than that of normal-ground extracts. Lipopolysaccharide (LPS)-stimulated Raw 264.7 cells were treated with different concentrations of Saururus chinensis extract and the amount of nitric oxide (NO) was determined; LPS-treated cells produced 2 times more NO than cells that were not treated with LPS. Moreover, the NO production in cells treated with Saururus chinensis extract was inhibited in a concentration-dependent manner. Because the stimulant-induced NO production is regulated by the inducible nitric oxide synthase (iNOS), we measured the iNOS protein level to elucidate the mechanism by which the NO production was inhibited. We found that the amount of iNOS decreased dosedependently. It was reduced by 53% at a Saururus chinensis extract concentration of 100 μg/mL. The protein expression of cyclooxygenase-2 (COX-2) in LPS-treated Raw 264.7 cells was inhibited by 31% at 100 μg/mL of Saururus chinensis extract. Gel shift of the nuclear factor kappa B-DNA complex occurred in LPS-treated cells and the intensity of the band decreased gradually in a concentration-dependent manner. Ultra-fine ground Saururus chinensis extract had a concentration-dependent inhibitory effect on the production of prostaglandin E₂, tumor necrosis factor α, interleukin 1β (IL-1β), IL-6, and IL-8 in LPS-treated Raw 264.7 cells, i.e., at 50 μg/mL of Saururus chinensis extract, their levels were decreased by 53, 67, 52, 37, and 21% respectively.