Blood Glucose–Reducing and Fat-Reducing Effects of a Novel Medicinal Mushroom, Grifola gargal (Agaricomycetes)

Grifola gargal Singer is a medicinal mushroom with biological effects such as antiatherogenic and antiosteoporotic activities. The objective of this study was to examine a blood glucose-reducing effect and a fatreducing effect of G. gargal supplementation in vivo. The effects of G. gargal powder (GGP) in a high-molecular weight hot water extract (GGH) and a low-molecular weight hot water extract (GGL) on blood glucose were investigated in streptozotocin (STZ)-induced diabetic ICR mice (STZ diabetic mice). A significant decrease in blood glucose was observed after 5 weeks of GGL supplementation (fraction with a molecular weight ≤ 6000 Da) in STZ diabetic mice. In the next test, we examined the antihyperglycemic and fat-reducing effects of GGL in diet-induced obesity (DIO) mice fed a high-fat diet. GGL facilitated reductions in blood glucose and body fat. This study confirms, to our knowledge for the first time, that administration of G. gargal extract has antihyperglycemic and body fat-reducing effects in STZ diabetic mice and DIO mice. Therefore, G. gargal is a promising functional food to prevent and treat diabetes and lifestyle-related diseases.