PSP and PSK

Informatioin Office of the Research Institute of Fungi Shanghai Teachers University

PSP and PSK are the 2 products of Yun Zhi ratified by Chinese Ministry of Public Health and Japanese Ministry of Public Health respectively.

PSK was first manufactured by Kureha Chemical Industry Co. Ltd. The PS in PSK represents polysaccharide and K represents the first alphabet of the name of this Company. It was originally written as PS-K and was later changed to PSK. o; The commercial name of the product is Krestin.

PSP was prepared by Professor Qing-yao Yang. It is like PSK and is also a kind of compound polysaccharide. On the molecules of the polysaccharide, the small molecular protein (polypeptide) is connected. So it is called Yun Zhi Duo Tang Tai or Yun Zhi Tang Tai. The Tang Tai English names were originally glycopeptide, proteoglucan, glycosaminoglucan, etc. But the polysaccharide is all composed of N-acetyl-amino-hexose. But the polysaccharides of PSP and PSK are not composed of N-acetylamino-hexose. So it is not suitable to use the name. So the word “polysaccharopeptide” or “polysaccharide-peptide” is used and is abbreviated as PSP or Ps-p.

According to the different degrees of extraction, there are a series of PSP products. PSP directly extracted from the mycelia of Yun Zhi is called Yun Zhi Polysaccharide-peptide (Trade mark Qing Kang) and PSP polysacchardie-peptide (Landford). The former is sold on the market of Mainland China and the latter is according to the export specifications and is sold overseas. These 2 products are mainly used for tumorous patients.

The essence of the product is obtained by further isolation of the crude product. It is called Essence of Mushroom (Yun Zhi) (The sole distributor is Winsor Health Products Ltd., Hong Kong) used for healthy purposes.

Japan is quite specialized in the research of Yun Zhi. Besides PSK, Hirose, S. et al, (1970), Naruse S. and Takeda S. (in 1970) and Sugiura M. (in 1980) isolated two anticancerous components of the mycelia of Yun Zhi respectively. The former is called

ASTO and latter D–II. In addition, Ito H. et al (in 1974) extracted from the fermented mash of Yun Zhi an anti-tumor component which does not contain protein and it is called Coriolan. Its chemical components are glucans (by Hayashida S. et al, in 1992). But the above-mentioned three components still remain in the process of pharmacological research and was not used in clinical application.

Though PSP and PSK are all a kind of protein bound polysaccharide and are all extracted from the deep layer cultivated mycelia, yet they use the different strains, fermented medium and different extracted methods. Thus there is a certain difference between PSP and PSK. It is known that in the polysaccharide of PSP there is fucose, while there is no fucose in PSP, which contains arabinose and rhamnose; while there are no such ingredients in PSK. On the other hand, according to the pharmacological and clinical research, PSP has the definite effect of alleviating pain and increasing appetite, while there is no such report on PSK. Comparison of Two Characterisitics of PSP and PSK

Items compared

Similarities

Dissimilarities

Fungi

Yun Zhi Coriolus versicolor (Fr.) Quel

PSP: Cov-1 strain PSK: CM-101 strain

Drug produced

PSP: capsule PSK: loose package

Powder color

brown

PSP: brown PSK: dark brown

Raw materials

deep-layer cultivated mycelia (2N)

Fermentation technology

with glucose as the main carbon source (25oC, 3 days)

PSP: nitrogenous source: soya beancake powder PSK: nitrogenous source: peptone and yeast cake

Extract and isolate

obtained by immersion in hot water

PSP: isolate by alcoholic precipitation PSK: isolate by salting out with (NH4)2SO4

Medicinal ingredients

protein bound polysaccharide; average molecular wt. 1 x 105 Da the polysaccharide is formed from many monosaccahrides containing

PSP: polysaccharides contain arabinose and rhmanose, but no fucose PSK: polysaccharides do not

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