Anti-inflammatory activity of the active components from the roots of Cosmos bipinnatus in lipopolysaccharide-stimulated RAW 264.7 macrophages.

We isolated a sesquiterpene lactone from the methanol extract of the roots of Cosmos bipinnatus, namely, MDI (a mixture of dihydrocallitrisin and isohelenin). The anti-inflammatory activity of MDI was evaluated using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. MDI significantly inhibited the expression of inducible nitric oxide synthase and cyclooxygenase-2. Consistent with these results, the production of NO and prostaglandin E-2 (PGE(2)) was suggested to be suppressed by MDI in a concentration-dependent manner (IC50 value was 0.94 and 2.88 mu gmL(-1) for NO and PGE(2), respectively). In addition, MDI significantly inhibited the expressions of pro-inflammatory cytokines such as IL-1, IL-6, IFN- and TNF-. Furthermore, MDI attenuated DNA-binding activity of NF-B by inhibiting the phosphorylation of IB. These results indicate that MDI isolated from the roots of C. bipinnatus shows anti-inflammatory activity in LPS-stimulated murine macrophages by modulating the NF-B pathway.