Saffron (Crocus sativus L.) powder as an ingredient of rye bread: an anti-diabetic evaluation.

In this study, a most consumer-acceptable rye bread (RB) containing saffron (S) powder (RB+S) was designed to verify its anti-diabetic properties, and to compare these effects with those of RB and S separately, matched to a similar dose of bioactive components, used in the high-fat (HF) diet in streptozotocin (STZ)-induced Wistar rats. After baking, beneficial antioxidant and sensory properties for RB enriched with 0.12% S were achieved. Twenty-four severely diabetic rats (fasting blood glucose (FBG) ≥350 mg/dL) were randomized to incorporate either 0.08% of pure S, or RB enriched with 0.12% S (the diet provided 0.08% of S), or RB alone into their diet for 5 weeks. As controls, nontreated, HF-feeding STZ-induced rats (positive control-HF/STZ) and rats receiving normal laboratory diet (negative control-C) were used. A significant FBG-lowering effect was observed (47%, 53%, and 54% reduction vs. HF/STZ; P<.05) after S, RB, and RB+S treatment. Improvements in the rats' glycemia were achieved by β-cell regeneration and increases in insulin secretion. Only in the S and RB+S group of rats, a significant (P<.05) increase in relative pancreas (vs. HF/STZ) was noted. A significant (P<.05) reduction in the concentration of thiobarbituric acid-reactive substances (TBARS) was achieved, whereas the ferric-reducing ability of plasma (FRAP) was not changed after S, RB and RB+S treatment (vs. HF/STZ). Triglyceride (TG) concentrations after S, RB, and RB+S treatment were significantly decreased (P<.05) versus HF/STZ. Both S and RB can be used in diabetic therapy, but no additional metabolic effect was achieved after consumption of RB+S.