The high stability of
sesame oil against oxidative deterioration is attributed to
lignans in its non-
glycerol fraction. The present study evaluates the effects of feeding sesame
lignans (
sesamin and
sesamolin) on Fe2+-induced oxidative stress in rats. Three groups, each of sixteen male weanling WNIN rats, were fed diets containing 200 g
casein/kg and l00 g oil/kg (group 1, groundnut oil; group 2,
sesame oil; group 3,
sesame oil +
sesamin (0.4 g/kg). After 45 d of feeding, eight rats from each group were injected with saline (9 g Na Cl/l, controls) intraperitoneally while the remaining eight rats were injected with 30 mg Fe2+/kg
body weight as
ferrous sulfate in
normal saline. The animals were killed after 90 min to evaluate hepatic function and
antioxidant status. Compared with those fed groundnut oil (group 1),
sesame oil-fed rats(groups 2 and 3) had lower levels of hepatic
thiobarbituric acid-reactive substances, serum
glutamate:
oxaloacetate transaminase activities and serum
glutamate pyruvate transaminase activities, indicating protection against Fe-induced oxidative stress. Despite similar
tocopherol levels in the three diets, hepatic a-
tocopherol levels were higher in rats fed the
sesame-oil diets (groups 2 and 3) compared with controls (group 1).However, activities of hepatic
antioxidant enzymes (
superoxide dismutase and
glutathione peroxidase) were significantly (P< 0-05) increased only in rats fed higher levels of
lignans (group 3). These observations suggest that sesame
lignans may have sparing effects on
tocopherols. The increased bioavailability of
tocopherols in the presence of dietary
lignans might be due to the regeneration of oxidized
tocopherols. The synergistic effects of
lignans with tocols has nutritional and therapeutic implications.