Potent nitric oxide inhibitory sesquiterpenoids from the rhizome of Curcuma aromatica Salisb.

One new sesquiterpenoid, curcaromatin (1), together with twenty-one known compounds 2-22, were isolated from the rhizomes of Curcuma aromatica Salisb. (Zingiberaceae). Their structures were established by extensive spectroscopic (1D and 2D NMR and HR-MS) analysis. Most of the isolated compounds were investigated for nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW264.7 cells. (-)-Xanthorrhizol (3) displayed the strongest NO inhibitory activity with an IC50 value of 4.3 mu M, which was 3.7-fold more active than the reference compound, aminoguanidine (IC50 15.9 mu M). The selectivity index (SI > 28.1) of compound 3 was almost 3-fold higher than that of aminoguanidine.