The Professor Chihiro Tohda at the Institute of Natural Medicine, Univer- sity of Toyama, who is the inventor of our supplemental product Diosgenin Gold, has pursued the research for more than 20 years to investigate the pharmacological mechanism with pharmacologically active components in the natural medicines and to find out unknown new pharmacologically active chemicals in the natural medicines of Japanese and Chinese origin.
The main research subject of Professor C.Tohda is to find out effective compounds for the prevention and/or treatment of dementia in plants used as natural medicines. Based on her long-term research experiences in this area as a specialist, she focused one component “diosgenin” contained in yam, and continued the researches and finally she could prove that diosgenin improved cognitive abilities successfully in the Alzheimer-model rats. She could also elucidate experimentally the target receptor protein of diosgenin and the mechanism of action in the rat brain. Further, she perfor- med the clinical research by using diosgenin soft capsules with healthy volunteers under placebo-controlled double blind conditions, and the clinical research clearly showed that the diosgenin soft capsule, same formulation as Diosgenin Gold, could improve the cognitive abilities statistically against placebo. The activity of the cognitive ability improvement was recognized more clearly in aged group of the healthy volunteers than younger group.