Diabetic mellitus (DM) is a carbohydrate metabolic disorder that involves high blood sugar because insulin works abnormally. Type 2 diabetes accounts for most of them. However, diabetes treatments such as GLP-1 and DPP-4 inhibitors commonly caused side effects including gastrointestinal disorders. Grifola frondosa (G. frondosa) revealed various pharmacological effects in recent studies. It has a variety of anti-cancer polysaccharides through host-mediated mechanisms. D-fraction in G. frondosa has apoptotic effects, promoting myeloid cell proliferation and differentiation into granulocytes-macrophages. It has also been shown to reduce the survival rate of breast cancer cells. Though, no further study has been conducted on the specific effects of G. frondosa in the db/db mouse. Therefore, we would like to research the blood glucose improving effect of G. frondosa, a natural material, in type 2 diabetes model mouse, in this study. G. frondosa was administered to the disease model mouse (BKS.Cg-+Leprdb/+Leprdb/OlaHsd) for 8 weeks to monitor weight and blood glucose changes every week. And we evaluated anti-diabetes effects by checking biomarker changes shown through blood. Experiment did not show statistically significant weight differences, but control groups showed significantly higher weight gain than G. frondosa administered groups. We collected blood from the tail veins of the db/db mouse each week. As a result, the lowest blood sugar level was shown in the 500 mg/ kg group of G. frondosa. Glucose in the blood was examined with HBA1c, and 7.8% was shown in the 500 mg/kg administration group, lower than in other groups. These results suggest the potential improvements of diabetes in G. frondosa.

The objective of the present study was to examine the effects of β-glucan originating from Aureobasidium on full-thickness skin wound healing in diabetic C57BL/KsJ-db/db mouse models. In the diabetic C57BL/KsJ-db/db model, test articles were topically applied twice a day for 20 days starting from 1 day after wounding. The results were compared to that of MadecassolTM ointment (madecassol; 1% Centella asiatica extracts) topically applied at a concentration of 100 mg/kg. Treatment with β-glucan resulted in significant (p<0.01 or p<0.05) and dose-dependent decreases in wound size compared with that of vehicle control showing increased wound size (WS, %). In addition, 50% contraction time (CT50) was dramatically and dose-dependently reduced, and inflammatory cells in granulation tissues of the wound area were significantly (p<0.01 or p<0.05) and dose-dependently reduced compared with that of vehicle control showing increased numbers of micro-vessels and fibroblasts as well as re-epithelialization. In the madecassol group, similar changes in inflammatory cells and fibroblasts with re-epithelialization were also observed, but madecassol did not influence angiogenesis. No meaningful changes in body weight were detected in all tested groups compared with the vehicle control. Therefore, these data suggest that β-glucan has a beneficial effect on diabetic delayed skin wound healing and may be useful to manage incurable skin wounds in diabetic animals.

We investigated the effect of Takju lees extract on blood glucose levels in the db/db mice (a murine model of type 2 diabetes mellitus). We fed 40 male db/db mice a control diet (G0, AIN93G) and experimental diets containing 1% (G1), 2% (G2), or 4% (G4) Takju lees extract for 4 weeks. We found no difference in food intake and body weight gain among the animal groups. In the G1 and G2 groups, plasma glucose levels decreased significantly between Days 10 and 21 compared with the G0 group. However, we found no difference in plasma glucose levels between groups G4 and G0. The change in insulin concentrations was not significant among these animal groups, and we found no significant difference in glucose transporter 4 (GLUT4) expression in the soleus muscle. These results suggest that the Takju lees extract has a beneficial effect in animals with type 2 diabetes.

In this study, we evaluated the antidiabetic effect of a submerged culture of Ceriporia lacerata mycelium (CL01) on hematological indices, as well as protein and mRNA expression of the insulin-signaling pathway, in db/db mice. After CL01 was administrated for 4 weeks, blood glucose levels decreased consistently, and plasma insulin and c-peptide levels each decreased by roughly 55.8%, 40% of those in the negative control (p<0.05). With regard to HOMA-IR, an insulin resistance index, insulin resistance of the CL01-fed group improved over that of the negative control group by about 62% (p<0.05). In addition, we demonstrated that the protein expression levels of pIR, pAkt, pAMPK, and GLUT4 and the mRNA expression levels of Akt2, IRS1, and GLUT4 in the muscle cells of db/db mice increased in the CL01-fed group compared to the corresponding levels in the control group. These results demonstrate that CL01 affects glucose metabolism, upregulates protein and gene expression in the insulin-signaling pathway, and decreases blood glucose levels effectively by improving insulin sensitivity. More than 90% of those who suffer from type 2 diabetes are more likely to suffer from hyperinsulinemia, hypertension, obesity, and other comorbidities because of insulin resistance. Therefore, it is possible that CL01 intake could be used as a fundamental treatment for type 2 diabetes by lowering insulin resistance, and these results may prove be useful as basic evidence for further research into the mechanisms of a cure for type 2 diabetes.