Anti-oxidant and inflammatory mediator's growth inhibitory effects of compounds isolated from Phyllanthus urinaria

Phyllanthus urinaria Linnea (Euphorbiaceae), is a traditional anti-hepatitis herb used in Taiwan. In continuation of our search for potent natural anti-inflammatory agents, from the ethanolic extract of this plant, nine compounds including phyllanthin (1), phyltetralin (2), trimethyl-3,4-dehydrochebulate (3), methylgallate (4), and rhamnocitrin (5), methyl brevifolincarboxylate (6), beta-sitosterol-3-O-beta-D-glucopyranoside (7), quercitrin (8), and rutin (9) were isolated. The structures of compounds 3 and 6 were established based on NMR and mass spectral studies. The isolates 1-9 were investigated for their antioxidant, and anti-inflammatory activities in vitro. In the antioxidant assay, the isolates 3, 4 and 6 exhibited significant DPPH radical scavenging activity with an IC50 value of 9.4, 9.8 and 8.9 mu M, respectively. On the other hand, in the inflammatory mediators growth inhibitory assay from LPS/interferon (IFN)-gamma-activated peritoneal macrophages, all the isolates except 7, significantly and dose-dependently inhibited the enhanced production of NO radicals, and such modulation was closely associated with the inhibition of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6. In addition, 30 mu M of isolates 3 and 6, and 50 mu M of 4, significantly arrest the mitogen-stimulated spleen cells in G0/G1 stage. This is the first report on Phyllanthus urinaria isolates for their growth inhibitory activities against inflammatory mediators, in addition to spleen cell cycle arrest in G0/G1 stage. Therefore, these isolates from Phyllanthus urinaria may be useful for the treatment of cell-mediated immune diseases. (C) 2007 Elsevier Ireland Ltd. All rights reserved.