Changes of materials that scavenge 1,1-diphenyl-2-picrylhydrazyl radicals in plasma by per-oral administration of Kampo medicine, Ninjin-yoei-to in rats.

The Kampo medicine, Ninjin-yoei-to, scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals in a dose-dependent fashion as did ascorbic acid and alpha-tocopherol. Ninjin-yoei-to, which is composed of 12 herbs, had a potent DPPH radical scavenging ability. We investigated the transition of the materials that scavenge DPPH radicals in plasma after oral administration of Ninjin-yoei-to to rats. When 1.0 g kg(-1) Ninjin-yoei-to was administered, the DPPH radical scavenging ability increased at 30 min and biphasic peaks were observed at 2 h and at 10 h. From the response-time profile, kinetic parameters including values for K(a) (absorption rate constant), t(max) (peak concentration time), t(1/2) (half-life) and MRT (mean residence time) of the radical scavenging ability in plasma could be calculated for DPPH radicals. K(a) values were 0.53 +/- 0.03 and 0.36 +/- 0.07 h, t(max) values were 2.1 +/- 1.04 and 8.56 +/- 2.69 h, t(1/2) values were 1.60 +/- 0.12 and 3.39 +/- 1.72 h, and MRT values were 4.14 +/- 1.59 and 8.18 +/- 2.55 h, respectively. These parameters calculated from the antioxidation dynamics were considered to offer a very meaningful procedure for examining the effects of Ninjin-yoei-to.