Anti-inflammatory activity of Chrysanthemum zawadskii var. latilobum leaf extract through haem oxygenase-1 induction

Chrysanthemum zawadskii var. latilobum (CZ) has been widely used as a tea in Korea. In this study, we investigated the involvement of anti-inflammatory haem oxygenase-1 (HO-1) in the inhibitory activity of a CZ leaf extracts on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. At the highest concentration of CZ leaf extract (50 μg/mL), NO production was 10% of that in LPS-stimulated macrophages, whereas iNOS protein expression was 5% of that in LPS-stimulated macrophages. CZ leaf extract also inhibited iNOS mRNA expression in a concentration-dependant manner, and at 50 μg/mL, iNOS mRNA expression was approximately 15% of that in LPS-stimulated cells. The CZ leaf extract induced HO-1 expression in a dose-dependent manner, and blocking HO-1 activity abolished the anti-inflammatory effect of CZ leaf extract. These results suggest that CZ leaf extract has a potent anti-inflammatory activity in RAW264.7 cells through the induction of HO-1.