This study investigated the hypolipidemic effect of whole grain Qingke (WGQ) and its influence on intestinal microbiota. Changes in the serum lipid, intestinal environment, and microbiota of Sprague-Dawley rats fed high-fat diets supplemented with different doses of WGQ were determined. Results showed that high doses of WGQ significantly decreased (P < 0.05) the Lee's index, serum total cholesterol, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol levels whereas they increased the body weight of the rats. Cecal weight and short-chain fatty acid (SCFA) concentration increased with increasing WGQ dose. An Illumina-based sequencing approach showed that the relative abundance of putative SCFA-producing bacteria Prevotella and Anaerovibrio increased in the rats fed the WGQ diet. Principal component analysis revealed a significant difference in intestinal microbiota composition after the administration of the WGQ diet. These findings provide insights into the contribution of the intestinal microbiota to the hypolipidemic effect of WGQ.

This study aimed to evaluate the protein metabolism effect of Zanthoxylum alkylamides and to explore the potential mechanism in streptozotocin (STZ)-induced diabetic rats. Diabetic rats were orally treated with 2, 4 and 8 mg per kg bw of alkylamides daily for 28 days. Alkylamides decreased the relative weight of the liver and food intake, significantly increased the relative skeletal muscle weight and significantly decreased the blood urea nitrogen levels. Insulin, insulin-like growth factor 1, total protein (TP) and albumin (ALB), globular proteins and ALB proteins/globulin protein levels in serum significantly increased. TP, RNA content and RNA/DNA ratio significantly increased in the skeletal muscle of diabetic rats. Real-time quantitative polymerase chain reaction results indicated that alkylamides significantly increased the mRNA expression of insulin receptor (InR), IGF1 and insulin-like growth factor 1 receptor (IGF1R) in the liver and skeletal muscle. Moreover, the mRNA and protein expression levels of PI3K, PKB and mTOR significantly increased, whereas those of atrogin-1, muscle ring finger 1 and FOXO in the skeletal muscle significantly decreased. Alkylamides may advance protein synthesis by the PI3K/PKB/mTOR signalling pathway and attenuate the catabolism of protein through the ubiquitin-proteasome pathway. Therefore, it was possible that alkylamides ameliorate protein metabolism disorders in diabetic rats by activating the mTOR pathway.

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About 4% of the world’s population has type 2 diabetes mellitus (T2DM), and the available hypoglycemic drugs for treating diabetes have some side effects. Therefore, research on the extraction of hypoglycemic components from plants has gradually become popular. This study aimed to investigate the hypoglycemic effects of polyphenol-rich Rosa roxburghii Tratt extract (RP) isolated from Rosa roxburghii Tratt fruit and of four constituents (IRP 1–4 ) isolated from RP on db/db mice. The results indicated that the oral administration of RP and IRP 1–4 could markedly decrease the food intake, water intake, fasting blood glucose (FBG), and serum insulin levels in the db/db mice. Glucose intolerance, insulin resistance, and oxidative stress were ameliorated in the RP and IRP 1–4 groups. Histopathological observation revealed that RP and IRP 1–4 could effectively protect the liver fat against damage and dysfunction. RP and IRP 1–4 also increased the hepatic and muscle glycogen contents by increasing the phosphorylation and reducing the expression of glycogen synthase kinase 3β (GSK3β). The activities of glucokinase (GCK), phosphoenolpyruvate carboxylase (PEPCK), and glucose-6-phosphatase (G6PC) and their respective mRNA expression levels in the liver of db/db mice were simultaneously increased and decreased in the intervention groups. RP and IRP 1–4 significantly increased the expression of phosphatidylinositol 3-kinase (P13K) and the phosphorylation of protein kinase B (AKT). These results indicate that RP and IRP 1–4 exhibit good hypoglycemic effects by activating the P13K/AKT signaling pathway and regulating the expression of FOXO1 and p-GSK3β proteins, controlling hepatic gluconeogenesis and improving hepatic glycogen storage insulin resistance. Therefore, RP and IRP 1–4 could be utilized as the hypoglycemic functional component to alleviate the symptoms of T2DM.