iNOS inhibitory activity of brazilin from Caesalpinia sappan

Two phenolic flavonoids were isolated from the traditional medicine of Eastern Asia, Caesalpinia sappan L (Leguminosae). Brazilin (1) showed a significant inhibitory activity against inducible Nitric Oxide Synthase (iNOS) in lipopolysaccharides (LPS)-induced macrophage RAW 264.7 cells with an IC$\sub$50/ value of 1.68 mg/ml, which is more potent than the positive control, L-N$\^$6/-(1-iminoethyl)lysine (IC$\sub$50/ 3.49 mM). On the other hand, caesalpine J (2) was found to be inactive in the present iNOS assay system despite of their structural similarities. (omitted)