6-Methoxyluteolin from Chrysanthemum zawadskii var. latilobum suppresses histamine release and calcium influx via down-regulation of FcεRI α chain expression.

Mast cells and basophils are important effector cells in immunoglobulin-E (IgE)-mediated allergic reactions. Using the human basophilic KU812F cells, we assessed the inhibitory effects of 6-methoxyluteolin, isolated from Chrysanthemum zawadskii, in the FcεRI-mediated allergic reaction. We determined that 6-methoxyluteolin inhibited anti-FcεRI α chain antibody (CRA-1)-induced histamine release, as well as elevation of intracellular calcium concentration [Ca2+]i in a dose-dependent manner. Moreover, the inhibitory effects of 6-methoxyluteolin on the cell surface expression and the mRNA level of the FcεRI α chain were determined by flow cytometric analysis and reverse transcription-polymerase chain reaction (RTPCR), respectively. Therefore, these results show that 6- methoxyluteolin is a potent inhibitor of histamine release and calcium influx via down-regulation of the FcεRI α chain.

Kaempferol isolated from Nelumbo nucifera stamens negatively regulates FcepsilonRI expression in human basophilic KU812F cells.

Mast cells and basophils perform important functions as pivotal effector cells in IgE-mediated allergic reactions. KU812F cells, a human basophilic cell line isolated originally from chronic myelocytic leukemia, express a high affinity receptor of IgE, FcepsilonRI. Kaempferol was extracted and isolated from a methanolic extract of flavonoid-rich Nelumbo nucifera stamens. In the present study, the inhibitory effects of kaempferol on FcepsilonRI expression in human basophilic KU812F cells was examined. Flow cytometric analysis revealed that FcepsilonRI expression on the cell surface was suppressed in a concentration-dependent manner when the cells were cultured with kaempferol. Moreover, RTPCR analysis showed that the mRNA levels for FcepsilonRI alpha- and gamma-chains were reduced as the result of kaempferol treatment in a concentration-dependent manner. Kaempferol showed its suppressive effects on intracellular Ca2+ concentration and histamine release from anti-FcepsilonRI alpha- chain antibody-stimulated cells in a concentration-dependent manner. These observations indicate that kaempferol may exert antiallergic effect via downregulation of FcepsilonRI expression and degranulation.

Further isolation of antioxidative (+)-1-hydroxypinoresinol-1-O-beta-D-glucoside from the rhizome of Salvia miltiorrhiza that acts on peroxynitrite, total ROS and 1,1-diphenyl-2-picrylhydrazyl radical.

A furanofuranoid lignan glycoside, with radical scavenging on peroxynitrite, total reactive oxygen species (ROS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, was isolated from the rhizome of Salvia miltiorrhiza and characterized as (+)-1-hydroxypinoresinol-1-O-beta-D-glucoside based on spectroscopic evidence. The compound exhibited peroxynitrite, total ROS and DPPH radical scavenging activities with IC50 values of 3.23 +/- 0.04, 2.26 +/- 0.07 and 32.3 +/- 0.13 microM, respectively. Penicillamine, Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) and L-ascorbic acid, acting as positive controls, showed radical scavenging activities with IC50 values of 6.72 +/- 0.25, 1.43 +/- 0.04 and 11.4 +/- 0.07 microM, respectively.