Results: MBG, but not MB, increased thiobarbituric acid-reactive species (TBA-RS) (lipid oxidation). MBG also induced sulfhydryl oxidation and decreased glutathione (GSH) levels, reflecting a reduction of antioxidant defenses. In contrast, MB and MBG did not alter carbonyl formation. We also found that MBG-induced increase of TBA-RS levels and decrease of GSH were prevented by free radical scavengers, implying that reactive species were involved in these effects.