Korean pine nut protein (PNP) has a variety of biological activities, which are good for human health, but its ability to preventing diabetes has not been reported. This study evaluated the effects of water-soluble proteins of Korean pine nut obtained from a dilute alkali extract on carbohydrate metabolism of type 2 diabetic mice on a model of diabetes induced using a high fat diet combined with streptozotocin. The results showed that the hypoglycemic effect of PNP at a middle dose was the most significant, which was 38.7% lower than that of control. The extract significantly improved the oral glucose tolerance and liver indexes, increased the activity of the carbohydrate metabolism enzymes, and regulated the expression of the function of key genes for carbohydrate metabolism. It had a positive effect on both insulin resistance and glycolytic/gluconeogenesis signaling. In conclusion, PNP can regulate fasting blood glucose, improve insulin resistance, correct the glucose metabolism disorder in diabetic mice, and have a positive regulatory role. As the functional food, it has the potential to be beneficial in the treatment of type 2 diabetes mellitus as a new hypoglycemic functional food.

This study explores the extraction and purification of polysaccharides from Dictyophora indusiata (D. indusiata) with its antioxidant and anti-weightlessness bone loss properties. An anionic polysaccharide (SADIP) with a molecular weight of 13.42 kDa was isolated and purified from D. indusiata. SADIP consists of a glucose-based sugar chain backbone. Its backbone consists of glycosidic linkages of →4)-α-D-Glcp-(1 → and →4)-β-D-Glcp-(1→, with sulfate groups attached at the O-6 position of →4)-β-D-Glcp-(1 → residues. Side chains were α-D-Glcp-(1 → 6)-α-D-Glcp-(1 → linked at C-6 position of →4,6)-α-D-Glcp-(1 → through O-6 bonds. In vitro, SADIP scavenged up to 99.32 ± 0.24 % of 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radicals and 76.72 ± 0.34 % of hydroxyl radicals. In vivo, SADIP reduced malondialdehyde (MDA) levels induced by weightlessness and increased low levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) caused by weightlessness. Additionally, three-point mechanical bending tests and Micro-CT analysis demonstrated that SADIP has ability to alleviate bone loss induced by weightlessness. This study provides a theoretical foundation for the rational developmation of D. indusiata resources.