Effect of Stay-Green Wheat, a Novel Variety of Wheat in China, on Glucose and Lipid Metabolism in High-Fat Diet Induced Type 2 Diabetic Rats

The use of natural hypoglycemic compounds is important in preventing and managing Type 2 diabetes mellitus (T2DM). Forty male Sprague-Dawley rats weighing 150–180 g were divided into four groups to investigate the effects of the compounds in stay-green wheat (SGW), a novel variety of wheat in China, on T2DM rats. The control group (NDC) was fed with a standard diet, while T2DM was induced in the rats belonging to the other three groups by a high-fat diet followed by a streptozotocin (STZ) injection. The T2DM rats were further divided into a T2DM control group (DC), which was fed with the normal diet containing 50% common wheat flour, a high dose SGW group (HGW) fed with a diet containing 50% SGW flour, and a low dose SGW group (LGW) fed with a diet containing 25% SGW flour and 25% common wheat flour. Our results showed that SGW contained cereal antioxidants, particularly high in flavonoids and anthocyanins (46.14 ± 1.80 mg GAE/100 g DW and 1.73 ± 0.14 mg CGE/100 g DW, respectively). Furthermore, SGW exhibited a strong antioxidant activity in vitro (30.33 ± 2.66 μg TE/g DW, p < 0.01). Administration of the SGW at a high and low dose showed significant down-regulatory effects on fasting blood glucose (decreasing by 11.3% and 7.0%, respectively), insulin levels (decreasing by 12.3% and 9.7%, respectively), and lipid status (decreasing by 9.1% and 7.5%, respectively) in T2DM rats (p < 0.01). In addition, the T2DM groups treated with SGW at a high and low dose showed a significant increase in the blood superoxide dismutase (1.17 fold and 1.15 fold, respectively) and glutathione peroxidase activities (1.37 fold and 1.30 fold, respectively) compared with the DC group (p < 0.01). The normalized impaired antioxidant status of the pancreatic islet and of the liver compared with the DC group was also significantly increased. Our results indicated that SGW components exerting a glycemic control and a serum lipid regulation effect may be due to their free radical scavenging capacities to reduce the risk of T2DM in experimental diabetic rats.