Evaluation of the hypoglycaemic and antioxidant effects of submerged Ganoderma lucidum cultures in type 2 diabetic rats

We aim to investigate the hypoglycaemic and antioxidant effects of submerged Ganoderma lucidum cultures and elucidate the potential mechanisms behind these effects using a type 2 diabetic rat model. Diabetic rats were daily fed with a high-fat diet supplemented with 1% or 3% freeze-dried whole submerged cultures of G. lucidum or mycelia for 5 weeks. We observed significantly decreased fasting plasma glucose levels, homoeostasis model assessment equation-insulin resistance, and plasma glucose in oral glucose tolerance test. Furthermore, we observed increased levels of glycogen, hepatic hexokinase, glucose-6-phosphate dehydrogenase, and intestinal disaccharidase activities. G. lucidum supplement downregulated the plasma levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and urea nitrogen as well as liver and kidney levels of thiobarbituric acid reactive substances. Based on the hypoglycaemic and antioxidant effects of G. lucidum submerged cultures, we recommend the potential application of these products as functional foods or additives for controlling type 2 diabetes. Abbreviations ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; BUN: Blood urea nitrogen; BW: Body weight; CREA: Creatinine; FPG: Fasting plasma glucose; G6Pase: Glucose-6-phosphatase; G6PD: Glucose-6-phosphate dehydrogenase; HOMA-IR: Homoeostasis model assessment of insulin resistance; OGTT: Oral glucose tolerance test; PTP: Protein tyrosine phosphatase; STZ: Streptozotocin; TBARS: Thiobarbituric acid reactive substances