Brazilin, the main constituent of Caesalpinia sappan L., is a natural red pigment that has been reported to possess anti-inflammatory properties. This study aimed to identify a novel anti-inflammatory mechanism of brazilin. We found that brazilin did not cause cytotoxicity below 300 μM, and activated heme oxygenase-1 (HO-1) protein synthesis in a concentration-dependent manner at 10-300 μM in RAW264.7 macrophages without affecting mRNA transcription of HO-1. Additionally, brazilin increased bilirubin production and HO-1 activity in RAW264.7 macrophages. In lipopolysaccharide (LPS)-stimulated macrophages, brazilin suppressed the release of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin (IL)-1β and tumor necrosis factor-α (TNF-α), and reduced the expression of inducible nitric oxide synthase (iNOS). A specific inhibitor of HO-1, Zn(II) protoporphyrin IX, blocked the suppression of NO production, cytokines release and iNOS expression by brazilin. These results suggest that brazilin possesses anti-inflammatory actions in macrophages and works through a novel mechanism involving the action of HO-1.
ASJC Scopus subject areas
- Drug Discovery
Hu, C-M., Liu, Y. H., Cheah, K. P., Li, J. S., Lam, C. S. K., Yu, W. Y., & Choy, C-S. (2009). Heme oxygenase-1 mediates the inhibitory actions of brazilin in RAW264.7 macrophages stimulated with lipopolysaccharide. Journal of Ethnopharmacology, 121(1), 79-85. https://doi.org/10.1016/j.jep.2008.09.030