Anticancer and Hypoglycemic Effects of Polysaccharides in Edible and Medicinal Maitake Mushroom [Grifola frondosa (Dicks.: Fr.) S. F. Gray]

Abstract

An investigation was carried out on the possible anticancer activity and hypoglycemic action of bioactive polysaccharides of Higher Basidiomycetes maitake mushroom [Grifola frondosa (Dicks.: Fr.) S. F. Gray], namely, D-fraction and SX-fraction, on human prostate cancer PC-3 cells in vitro and type 2 diabetic patients. D-fraction at і480 mg/mL was highly cytotoxic to prostatic cancer PC-3 cells, inducing nearly complete cell death (>95%) in 24 hours. The combination of a low concentration (60 [mg/mL) of D-fraction (with no cytotoxic effect) and vitamin С (200 mM) was also found to be as effective as 480 mg/mL D-fraction alone, suggesting a synergistic potentiation of D-fraction with vitamin C. An anticancer agent carmustine (BCNU), capable of inducing a -50% reduction in cell viability by itself (50 mM), then showed its enhanced cytotoxicity with D-fraction (60 mg/mL), resulting in a ~90% cell viability reduction. In clinical studies on hypoglycemic effect of SX-fraction, 5 patients with type 2 diabetes under oral medications demonstrated improved glycemic levels with G. frondosa polysacchande caplets (MFCs) containing active SX-fraction. One patient showed complete glycemic control with MFCs and is currently free of medications, whereas others showed over 30% decline in their serum glucose levels with MFCs in 2 to 4 weeks. Therefore, polysaccharides of G. frondosa may have therapeutic implications in the effective treatments of prostate cancer (anticancer activity) and type 2 diabetes (hypoglycemic action).