Inhibition of NO production in LPS-stimulated RAW264.7 macrophage cells with curcuminoids and xanthorrhizol from the rhizome of Curcuma xanthorrhiza Roxb. and quantitative analysis using HPLC

Abstract

Three diarylheptanoids, bisdemethoxycurcumin (1), curcumin (2), and demethoxycurcumin (3), two diarylpentanoids, 3,3′-bis(7,7′-hydroxy-6,6′-methoxyphenyl)-penta-(3E,2′E)-3,2′-dien-1-one (4) and 3,3′-bis(7,7′-hydroxy-6-methoxyphenyl)-penta-(3E,2′E)-3,2′-dien-1-one (5), and a bisabolane sesquiterpene, xanthorrhizol (6), were isolated from the rhizome of Curcuma xanthorrhiza through repeated column chromatography. Silica gel (SiO2), octadecyl silica gel (ODS), and Sephadex LH-20 resins were used. Compounds were identified by spectroscopic methods, including nuclear magnetic resonance, mass spectrometry, and infrared spectroscopy. Compounds 1 (IC50: 8.21 μM), 2 (IC50: 10.01 μM), 3 (IC50: 4.86 μM), and 4 (IC50: 2.20 μM) inhibited nitric oxide production in LPS-stimulated RAW264.7 macrophage cells. High performance liquid chromatography was used to determine the content of curcuminoids and xanthorrhizol in C. xanthorrhiza extract to be 0.46±0.08% (1), 10.69±0.18% (2), 2.35±0.06% (3), 0.18±0.05% (4), 0.03±0.01% (5), and 27.47±2.42% (6).