Hydrolysates of coix seed prolamins (CHPs) have an excellent hypoglycemic effect and can effectively inhibit α-glucosidase, which is the therapeutic target enzyme for type 2 diabetes mellitus. However, its hypoglycemic components and molecular mechanisms remain unclear, and its stability in food processing needs to be explored. In this study, four potential α-glucosidase inhibitory peptides (LFPSNPLA, FPCNPLV, HLPFNPQ, LLPFYPN) were identified and screened from CHPs using LC-MS/MS and virtual screening techniques. The results of molecular docking showed that the four peptides mainly inhibited α-glucosidase activity through hydrogen bonding and hydrophobic interactions, with Pro and Leu in the peptides playing important roles. In addition, CHPs can maintain good activity under high temperatures (40~100 °C) and weakly acidic or weakly alkaline conditions (pH 6.0~8.0). The addition of glucose (at 100 °C) and NaCl increased the inhibitory activity of α-glucosidase in CHPs. The addition of metal ions significantly decreased the inhibitory activity of α-glucosidase by CHPs, and their effects varied in magnitude with Cu²⁺ having the largest effect followed by Zn²⁺, Fe³⁺, K⁺, Mg²⁺, and Ca²⁺. These results further highlight the potential of CHPs as a foodborne hypoglycemic ingredient, providing a theoretical basis for the application of CHPs in the healthy food industry.

The self-assembled structures of coix seeds affected the enzymatic efficiency and doesn't facilitate the release of more active peptides. The influence of heating combined with ultrasound pretreatment (HT + US) on the structure, enzymatic properties and hydrolysates (CHPs) of coix seed prolamin was investigated. Results showed that the structural of coix seed prolamins has changed after HT + US, including increased surface hydrophobicity, reduced α-helix and random coil content, and a decrease in particle size. So that, leads to changes in thermodynamic parameters such as an increase in the reaction rate constant and a decrease in activation energy, enthalpy and enthalpy. The fractions of <1000 Da, degree of hydrolysis and α-glucosidase inhibitory were increased in the HT + US group compared to single pretreatment by 0.68%-17.34%, 12.69%-34.43% and 30.00%-53.46%. The peptide content and α-glucosidase inhibitory activity of CHPs could be maintained at 72.21 % and 57.97 % of the initial raw materials after in vitro digestion. Thus, the findings indicate that HT + US provides a feasible and efficient approach to can effectively enhance the enzymatic hydrolysis efficiency and hypoglycaemic efficacy of CHPs.

The adzuki bean is a mature seed of the red bean leguminous plant, and people like to eat it because of its nutritious properties and moderate proportion of amino acids. Adzuki bean germination and the enrichment of GABA greatly improve the health effects of the adzuki bean. The effects of the GABA-rich adzuki bean on the expression of insulin-pathway-related genes and proteins in the liver of T2DM mice were studied via Western blotting and qPCR. The results showed that a GABA-rich adzuki bean diet could promote glycogen synthesis in the liver of T2DM mice, inhibit the activities of PEPCK and G-6-Pase, and significantly down-regulate the gene expression levels of PEPCK, G6PC and FOXO1 (p < 0.05) and the phosphorylation levels of FOXO1 and GSK3β. In addition, it can also up-regulate the expression of the AMPKα gene and down-regulate the expression of the SREBP1c gene to inhibit the synthesis of triglycerides and cholesterol in T2DM mice. Lipid accumulation in mice can alleviate glucose and lipid metabolism disorders and play an effective role in regulating blood glucose at liver tissue targets. This study suggested that the GABA-rich adzuki bean can improve hyperglycemia in type 2 diabetic mice by activating the IRS/PI3K/AKT signaling pathway in the liver.

Obesity and overweight have increasingly posed a serious challenge to public health security. This study systematically evaluated the reversal and regulatory effects of a composite flavonoid component mimicking the composition of adzuki bean flavonoids on high-fat diet (HFD)-induced obesity, related lipid metabolism disorders, and impaired liver function, based on lipid metabolomics and an HFD-induced obese mouse model. The results demonstrated that sustained HFD intake led to significant weight gain, increased adiposity index, dyslipidemia, and altered brown adipose tissue (BAT) cell status in mice, while also exerting adverse effects on hepatic lipid deposition and the lipid metabolic profile associated with liver fibrosis. Intervention with an adzuki bean flavonoid mimic (ABFM) effectively prevented further weight gain and ameliorated abnormal expression of serum lipid and liver function-related indicators. Furthermore, we found that ABFM alleviated HFD-induced liver damage and mitigated the whitening tendency of brown adipose tissue. Lipidomics analysis revealed that ABFM intake significantly improved abnormal hepatic lipid metabolic profiles, notably downregulating the expression levels of diacylglycerol (DG) and phosphatidylglycerol (PG), while markedly ameliorating sphingolipid metabolism disorders and ceramide (Cer) levels, which are highly associated with liver fibrosis. These findings further elucidate the mechanisms by which adzuki bean flavonoid components improve diet-induced obesity and associated liver injury, providing a theoretical basis for exploring safe and effective dietary intervention strategies based on plant flavonoids.