Anti-Type II Diabetic Effects of Coix Seed Prolamin Hydrolysates: Physiological and Transcriptomic Analyses

Abstract

Previous studies have demonstrated that enzymatically prepared coix seed prolamin hydrolysates (CHPs) contain several bioactive peptides that efficiently inhibit the activity of target enzymes (α-glucosidase and dipeptidyl kinase-IV) in type 2 diabetes mellitus (T2DM). However, the anti-T2DM effects and potential mechanisms of CHPs as a whole in vivo have not yet been systematically explored. Therefore, we evaluated the preventive, therapeutic, and modifying effects of CHPs on T2DM by combining physiological and liver transcriptomics with a T2DM mouse model. The results showed that sustained high-fructose intake led to prediabetic symptoms in mice, with abnormal fluctuations in blood glucose and blood lipid levels. Intervention with CPHs effectively prevented weight loss; regulated abnormal changes in blood glucose; improved impaired glucose tolerance; inhibited the abnormal expression of total cholesterol, triglycerides, and low-density lipoproteins; alleviated insulin resistance; and restored pancreatic islet tissue function in mice fed a high-fructose diet. In addition, we found that CHPs also play a palliative role in the loss of liver function and protect various organ tissues (including the liver, kidneys, pancreas, and heart), and are effective in preventing damage to the liver and pancreatic islet cells. We also found that the intake of CHPs reversed the abnormally altered hepatic gene profile in model mice and identified 381 differentially expressed genes that could serve as key genes for preventing the development of T2DM, which are highly correlated with multiple glycolipid metabolic pathways. We demonstrated that CHPs play a positive role in the normal functioning of the insulin signalling pathway dominated by the IRS-1/PI3K/AKT (insulin receptor substrates-1/phosphoinositide 3-kinase/protein kinase B) pathway. In summary, CHPs can be used as effective food-borne glucose-modifying components of healthy foods.