چکیده (انگلیسی):

The current study aimed to investigate the possible beneficial effects of grape seed extract
(GSE) on some metabolic and biochemical changes associated with streptozotocin (STZ; 50 mg/kg;
i.p.)-induced hyperglycaemia in male rats. Blood samples were used to determine serum levels of
glucose, insulin, total cholesterol (TC) and triglycerides (TG). Some biochemical markers for oxidative
stress viz., serum lipid peroxides level (measured as malondialdehyde; MDA) and total antioxidant
capacity as well as serum nitric oxide (NO) level were assessed. Hyperglycaemic animals
received GSE (100 and 300 mg/kg/day) orally on daily basis for 28 consecutive days and their effects
were determined 24 h after the administration of the last dose. Results of the present study revealed
that STZ-induced hyperglycaemia is associated with decreased serum insulin level with increased
levels of TC and TG. Hyperglycaemia was also associated with increased level of serum MDA
together with decreased total antioxidant capacity and level of serum NO. GSE succeeded to
improve the serum glucose level in STZ-treated rats in a dose dependent manner. It also showed
a restoration of the increased serum level of TC, TG and MDA and of the suppressed insulin
and total antioxidant capacity as well as the decreased plasma level of NO. From our results it
can be concluded that GSE has beneficial effects against the biochemical changes associated with
STZ-induced hyperglycaemia. These beneficial effects might be related to the ability of GSE to
improve hyperglycaemia in addition to its anti-oxidant property.