Effects of Grifola frondosa non-polar bioactive components on high-fat diet fed and streptozotocin-induced hyperglycemic mice.

Context: Consumption of medicinal mushrooms for disease prevention and maintaining health has a very long history in Asia. Grifola frondosa (Fr) S. F. Gray (GF) (Meripilaceae) is a medicinal fungus popularly used for enhancing immune systems, lowering blood glucose, and improving spleen, stomach, and nerve functions. Objective: This study examines the hypoglycemic effects of GF in vitro and in vivo, and analyzes the chemical profiles of its bioactive components. Materials and methods: In vitro hypoglycemic effects of GF was evaluated enzymatically using alpha-amylase and alpha-glucosidase inhibition assays, whereas in vivo study was conducted on high-fat diet fed and streptozotocin (HFD + STZ)-induced hyperglycemic mice. GC-MS was used to determine the chemical profiles of bioactive components. Results: The non-polar fraction of GF exhibited a stronger anti-alpha-glucosidase activity (IC50: 0.0332 mg/ml) than acarbose, but its anti-alpha-amylase activity (IC50: 0.671 mg/ml) was weaker. Oral administration of GF at 600 mg/kg (GF600) significantly lowered the blood glucose, HbA1c, average blood glucose, and serum total cholesterol levels in hyperglycemic mice. Although GF was found to contain mainly oleic acid and linoleic acid, their levels in the fungus were low, suggesting that the effects of GF on HFD + STZ-induced hyperglycemic mice could be due to factors other than these fatty acids. Conclusion: These results conclude that GF possesses anti-alpha-glucosidase activity, and hypoglycemic effect in HFD + STZ-induced hyperglycemic mice.