This study was conducted to determine the
antioxidant effects of a Polygonatum extract compared with the major
antioxidant,
vitamin E, in rabbits fed a high-
cholesterol diet. Rabbits were given a high-
cholesterol (0.5%, wt/wt) diet with
vitamin E (0.03%, wt/wt) or a Polygonatum extract (0.05%, wt/wt) for 8 weeks. The
body weight gain (g/week) was only significantly increased only in the high-
cholesterol-fed control group, yet the relative liver weight was significantly lower in the Polygonatum group compared with the other groups. The supplementation of
vitamin E and Polygonatum extract led to an increase in the hepatic
catalase (CAT) activity without any change in
superoxide dismutase (SOD) and
glutathione peroxidase (GSH-Px) activities. Hepatic total
glutathione content was significantly higher in the Polygonatum group than in the other groups. The level of hepatic mitochondrial H(2)O(2) was significantly lower in the two supplemented groups compared with the control group, whereas the level of cytosolic H(2)O(2) was only significantly lower in the Polygonatum group than in the control group. The level of plasma
thiobarbituric acid-reactive substances (
TBARS) was only significantly lower in the
vitamin E group, whereas the level of hepatic
TBARS was slightly lower in the Polygonatum group than in the other groups. In the case of the
high-density lipoprotein-related
antioxidant enzyme,
vitamin E supplementation produced the highest plasma
paraoxonase (PON) activity compared with the other groups, although there was no difference in the hepatic PON activity among the groups. Meanwhile, the plasma
vitamin E concentration was significantly higher in the
vitamin E and Polygonatum groups than in the control group; however, plasma
vitamin A concentration did not differ significantly between the groups. As regards the
mRNA expressions of hepatic
antioxidant enzymes, the
vitamin E and Polygonatum extract supplementation had no effect on the SOD, CAT, GSH-Px, and PON
mRNA expression. Accordingly, these results indicate that the Polygonatum extract had a positive effect on the
antioxidant defense system based on decreasing the content of hepatic
TBARS and
hydrogen peroxide, increasing the CAT activity and total
glutathione level in the liver, and sparing the plasma
vitamin E. Thus, further studies on the functional components in Polygonatum extract and their biological efficacies are needed.