Japanese Yam is registered as the name of “Sanyaku“ in Japanese Pharmacopeia(JP), which is the specification document for quality. “Sanyaku” is named originally for Japanese Yam in Chinese expression, and “Sanyaku” registered in JP is the natural medicine prepared from the dried root of certain kinds of Japanese Yam after peeling off the root skin.
“Sanyaku” has been considered effective as nourishing and analeptic, thirst-quenching and antidiarrhea. Therefore, it has been used for gastrointestinal weakness, anorexia, physical fatigue, enteritis, enuresis and night sweat. “Sanyaku” contains starch, amino acids, glycoprotein, choline, allantoin, diastase and catalase.
According to the Japanese Pharmaceutical Association of Natural Medicines, “Sanyaku” is reported to have pharmacological activities such as male hormone-like activity, SOD-like activity, immune-activating property, anti-inflammatory activity and hypoglycemic activity.
“Sanyaku” has been used in many Chinese medicines, and for example, “Sanyaku” is contained in the following Chinese medicines as key component such as Hachimijiougan, Gisshajinnkigan, Rokumigan, Keihi- tou and Sanreibyakujyutusan.