AbstractThe antioxidant functions of two feruloyl oligosaccharide (FO1 and FO2) were investigated in vivo and in vitro. Effects of FO1 and FO2 on hemolysis of rat red blood cell (RBC) and malondialdehyde (MDA) formation in rat liver homogenate and rat liver mitochondria in vitro were studied. Hemolysis of rat RBC and MDA formation in rat liver homogenate and rat liver mitochondria were inhibited in a dosage-dependent manner by FO1 and FO2 in the tested concentration range of 0.5 to 10 mg/mL. The results showed that FO1 and FO2 had antioxidative activity in vitro, and the effect of FO2 was better than that of FO1. With increasing dosage, FO1 and FO2 could increase the activity of SOD and GSH-Px in serum of S180 tumor-bearing mice, reduce the level of MDA, and thus improve the activity of the antioxidant in vivo. When the dosage reached 250 mg/kg/d, FO2 was more likely to improve the capabilities of the antioxidants of tumor-burdened mice than were 5-FU and FO1 in vivo.Thus, these oligosaccharides may be used as functional biological materials produced from fermented lignocellulose of WB.