Cytoprotective effect of silymarin against sodium fluoride-induced oxidative stress in rat erythrocytes.

Silymarin is a potent antioxidant agent isolated from milk thistle seeds ofSilybum marianum (L.) Gaertn (Family Asteracae), comprised mainly of threeisomeric flavonolignans: silibinin, silydianin, and silychristin. The aim of the presentstudy was to evaluate the protective antioxidant effects of silymarin in erythrocytesof fluoride-treated rats. Fifty adult male Wistar rats were divided into five groups often each: a normal control group received low fluoride (F) drinking water (DW) and astandard diet throughout the study; a second group received only 600 ppm NaF (271ppm F ion) in their DW for seven days. A third group received 10 mg silymarin/kg bwintraperitoneally (i.p.) for one week, followed by 600 ppm NaF in their DW for sevendays. The fourth group received 20 mg silymarin/kg bw i.p. for one week, followed by600 ppm NaF in their DW for seven days. The fifth group received 10 mg vitamin C/kgbw i.p. for one week, followed by 600 ppm NaF in their DW for seven days. At the endof the one-week pre-treatment period, the erythrocytes of the rats were isolated; andcatalase and superoxide dismutase activities, reduced glutathione, and lipidperoxidation levels were determined. Pre-treatment with 20 mg silymarin (and, to alesser extent, with 10 mg silymarin and 10 mg vitamin C), prior to NaF intoxication,maintained the basal levels of antioxidant parameters and restored the enzymaticantioxidant activities in the erythrocytes when compared with those in the controlgroup. We conclude that silymarin has a potent ameliorative effect on NaF-inducedoxidative stress in rat erythrocytes.