The present study was undertaken to investigate the biochemical effects of aqueous stem bark extract of D. guineense
on activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glucose 6-phosphate dehydrogenase (G6PDH)), and malondialdehyde (MDA) and total protein concentrations in normal Wistar rats. Ten adult male Wistar rats weighing 150 to 180 g were randomly assigned to two groups of five rats each: control group and observation group. The observation group received 1000 mg/kg body weight, bwt, of aqueous extract orally for twenty-eight days, and assays were performed on weekly basis. Results of phytochemical analyses of the plant stem bark revealed the presence of tannins (3.76 ± 0.31 %), alkaloids (1.22 ± 0.06 %), phenols (1.40 ± 0.03 %), flavonoids (0.92 ± 0.03 %), saponins (0.18 ± 0.02 %), glycosides (0.04 ± 0.01 %) and steroids (0.04 ± 0.01 %). There was no significant difference in the concentration of total protein between the two groups (p
> 0.05). The concentration of MDA was significantly lower in observation group than in control group (p
< 0.05). However, the activities of G6PDH, SOD, CAT and GPx were significantly higher in observation group than in control group (p
< 0.05). The extract potentiated the activities of G6PDH, SOD, catalase and GPx.