STIMULATION OF NITRIC-OXIDE SYNTHESIS IN MACROPHAGE CELL-LINE RAW-264.7 CELLS BY SEVERAL TRADITIONAL CHINESE HERBAL MEDICINES

The effect of 18 traditional Chinese herbal medicines [Kampo medicines (KMs)] on nitric oxide (NO) synthesis in vitro was assessed by using macrophage cell line RAW 264.7 cells. All of the prescriptions enhance d NO synthesis, and eight prescriptions showed strong activity relativ e to the other remaining prescriptions. After dialysis of the water-so luble part of the prescriptions, the retaintate showed significant act ivity, suggesting that macromolecular fractions enhanced NO synthesis. Egg white lysozyme, which can bind to lipopolysaccharide (LPS) and ne utralize its biological activities, abrogated NO synthesis of a part o i the macromolecular fractions. These results suggest that KM-stimulat ed NO synthesis was independent of the contaminated LPS. The NO synthe sis was inhibited by NC-monomethyl-L-arginine acetate, an inhibitor of nitric oxide synthase (NOS), showing that induced NO resulted from th e activation of inducible NOS but not from nitrite in crude drugs. (C) 1995 Wiley-Liss, Inc.