Silibinin attenuates oxidative metabolism and cytokine production by monocytes from preeclamptic women

Silibinin is a polyphenolic plant flavonoid with anti-inflammatory properties. The present study investigated the effect of silibinin on oxidative metabolism and cytokine production - tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)12, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, IL-10, and transforming growth factor beta (TGF-beta(1)) - by peripheral blood monocytes (PBM) from preeclamptic pregnant women. It is a case-controlled study involving women with preeclampsia (PE, n = 30) compared with normotensive pregnant (NT, n = 30) and with non-pregnant (NP, n = 30) women. Monocytes were obtained and cultured with or without silibinin (5 mu M or 50 mu M) for 18 h. Superoxide anion (O-2-) and hydrogen peroxide (H2O2) release were determined by specific assays, and cytokine levels were determined by immunoenzymatic assays (ELISA). Monocytes from preeclamptic women cultured without stimulus released higher levels of O-2(-), H2O2 and TNF-alpha, and lower levels of IL-10 and TGF-beta(1) than did monocytes from NT and NP women. Treatment in vitro with silibinin significantly inhibited spontaneous O-2- and H2O2 release and TNF-alpha production by monocytes from preeclamptic women. The main effect of silibinin was obtained at 50 mu M concentration. Thus, silibinin exerts anti-oxidative and anti- inflammatory effects on monocytes from preeclamptic pregnant women by inhibiting the in vitro endogenous release of reactive oxygen species and TNF-alpha production.