Inhibitory effects of ginsenosides from the root of Panax ginseng on stimulus-induced superoxide generation, tyrosyl or serine/threonine phosphorylation, and translocation of cytosolic compounds to plasma membrane in human neutrophils.

The effects of five ginsenosides (G-Rh2, -Rd, -Rb1, -Rb2, -Rh1) isolated from the root of Panax gingseng on stimulus-induced superoxide generation in human neutrophils were evaluated by measuring the reduction of ferricytochrome c. The tyrosyl or serine/threonine phosphorylation of neutrophil proteins and translocation of p47phox, p67phox, and Rac to the plasma membrane were detected using specific monoclonal antibodies. G-Rh2 significantly suppressed superoxide generation induced by N-formylmethionyl-leucylphenylalanine (fMLP), phorbol 12-myristate 13-acetate (PMA), and arachidonic acid (AA) in a concentration-dependent manner. G-Rh1 showed a comparably lower suppression on fMLP-induced superoxide generation. G-Rd, -Rb1, and -Rb2 also suppressed AA-induced superoxide generation in high concentrations. G-Rd and G-Rb1 showed no effect on fMLP- and PMA-induced superoxide generation. FMLP-, PMA-, and AA-induced tyrosyl or serine/threonine phosphorylation and translocation of p47phox, p67phox, and Rac to the plasma membrane were in parallel with the suppression of the stimulus-induced superoxide generation.