General Explanation for Japanese Yam used as Natural Medicine

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.

ジオスゲニンの新たな効能
ジオスゲニンによる神経細胞の軸索・樹状突起の変化
マウス(小型ネズミ)の大脳皮質の神経細胞

Reference

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Heat Shock Cognate 70 inhibitor, VER-155008, reduces memory deficits and axonal degeneration in a mouse model of Alzheimer’s disease.
Frontiers in Pharmacology, (2018) 9, 48. doi: 10.3389/fphar.2018.00048.

3) Tohda C, Yang X, Matsui M, Inada Y, Kadomoto E, Nakada S, Watari H, Shibahara N.
Diosgenin-Rich Yam Extract Enhances Cognitive Function: A Placebo-Controlled, Randomized, Double-Blind, Crossover Study of Healthy Adults.
Nutrients, (2017) 9(10), 1160. doi:10.3390/nu9101160

4) Tohda C, Lee Y-A, Goto Y, Nemere I.
Diosgenin-induced cognitive enhancement in normal mice is mediated by 1,25D3-MARRS.
Scientific Reports, (2013) Dec 2;3:3395. doi: 10.1038/srep03395.

5) Tohda C, Urano T, Umezaki M, Nemere I, Kuboyama T.
Diosgenin is an exogenous activator of 1,25D3-MARRS/Pdia3/ERp57 and improves Alzheimer’s disease pathologies in 5XFAD mice.
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