Yukmijihwang-tang (YMJd, or YMT in some reports) or Luweidihuang-tang is a multi-herbal tonic which has been consumed for centuries as a memory improver and cognition developer. It has been postulated as a treatment for dementia. It is mainly available in the Far Eastern Asian continent and uses extracts from 6 herbs:- Rehmannia radix or R. glutinosa, Dioscoreae radix, Corni fructus, Cornus officinalis, Hoelen, Mountain cortex radicis and Alismatis radix (Park et al., 2005), Dioscorea batatas, Alisma orientale, Poria cocos and Paeonia suffruticosa (Liu et al., 2008; Xie et al., 2006, 2008). Many claims are made for this potent mix from treating diabetes, backache, alopecia to dizziness and arthritis. One of the issues is defining the content and quality of commercial preparations of Yukmijihwang-tang. It is a complex mix and its componentry is very difficult to characterise. Markers are essential and 5-hydroxymethyl-2-furaldehyde (5-HMF) has been used because it is a quality indicator which is easily measured using HPLC-DAD (High Performance Liquid Chromatography – Diode Array Detector). The same technique is now available to monitor levels of actives such as paeoniflorin and loganin (Won et al., 2010).
The clinical research on this product to improve memory and cognition where human studies are concerned is few and far between. Only one study has been conducted. In terms of human studies, researchers in Seoul mainly at Kyung Hee University examined YMJd’s effect in a placebo controlled, double-blinded study using students. Whilst the placebo group of 15 students received two starch capsules, the 20 others in the treatment group received 2 capsules of 650 mg YMJd, 3 times a day for 6 weeks. Interestingly, as well as YMJd, they also received an extract of Lycii fructus. Each student participated in a K-WAIS test – a Korean Intelligence test and the results before and after treatment were significantly greater for the group treated with YMJd compared to the placebo group. The students also participated in P300 assessments using auditory tests of various sorts and a similar finding was reported. Unfortunately, with only one study available to examine, further research is required before any firm conclusions can be drawn. Extrapolation to rat models yields further clues including changes to gene expression in the hippocampus (Rho et al., 2005) whereby neural degeneration was blocked and some neural growth even observed. It was then reported that ameliorated both learning and memory impairment in amnesia induced by ibotenic acid ascribed to a neuroprotective effect in hippocampal cholinergic neuron degeneration (Kang et al., 2006). In current marketing terms, it’s unlikely YMJd is suitable yet for inclusion as a beverage supplement particularly if claims are required.
References
Kang, M., Kim, J.H., Cho C., Lee K.Y., Shin M., Hong,M., Shim, I., Bae, H. (2006) Effects of Yukmijihwang-tang derivatives (YMJd) on ibotenic acid induced amnesia in the rat. Biol. Pharm. Bull. 29 pp.1431–1435
Liu, H.-R., Tang, X.-Y., Dai, D.-Z., and Dai, Y., (2008) Ethanol extracts of Rehmannia complex (Di Huang) containing no Corni fructus improve early diabetic nephropathy by combining suppression on the ET-ROS axis with modulate hypoglycemic effect in rats. J. Ethnopharmacol., 118, pp. 466-472
Park E, Kang M, Oh J, Jung M, Park C, Cho C, Kim C, Ji S, Lee Y, Choi H, Kim H, Ko S, Shin M, Park S, Kim H, Hong M, Bae H. (2005) Yukmijihwang-Tang derivatives enhance cognitive processing in normal young adults: a double-blinded, placebo controlled trial. Am J Chin Med. 33 pp. 107–115
Rho S, Kang M, Choi B, Sim D, Lee J, Lee E, et al. (2005) Effects of Yukmijihwang-tang derivatives (YMJd), a memory enhancing herbal extract, on the gene-expression profile in the rat hippocampus. Biol Pharm . Bull. 28 pp. 87–93.
Won, J.B., ma, J.Y., Ma, C.J. (2010) Simultaneous Determination of Four Marker Components in Yukmijihwang Tang by High Performance Liquid Chromatography/ Diode Array Detector. Arch. Pharm. Res., 33 (4) pp. 619-623
Xie, B., Gong, T., Tang, M., Mi, D., Zhang, X., Liu, J., and Zhang, Z. (2008) An approach based on HPLC-fingerprint and chemometrics to quality consistency evaluation of Liuwei Dihuang Pills produced by different manufacturers. J. Pharm. Biomed. Anal., 48, pp. 1261-1266
Xie, P., Chen, S., Liang, Y.-Z., Wang, X., Tian, R., and Upton, R. (2006) Chromatographic fingerprint analysis – a rational approach for quality assessment of traditional Chinese herbal medicine. J. Chromatogr. A., 1112, pp. 171-180
Totally weird !