PSK Heavy Metal Tests

Production of Trammune PSK
The raw material for PSK (Trametes versicolor Proteoglycan Concentrate) is now produced commercially in suspended culture from mycelial biomass produced in glass fermentation vessels. Fermentations are carried out for several days with stepwise feeding with fresh medium. The biomass is collected by centrifugation and subjected to multi-step extraction with hot water. The active substance is recovered from the concentrated extract by precipitation with ethanol.

Heavy Metals Presence in Pharmaceutical Products

In the manufacturing process, heavy metals may occur despite the use good manufacturing practices (e.g. undetected contaminants from starting materials or reagents), those coming from the process (e.g. leaching from pipes and other equipment), and those that occur naturally (e.g. from naturally derived plant or mineral sources). As a consequence, pharmaceutical regulatory bodies, such as the TGA, require that tests be conducted to show that every product does not contain heavy metals above a stated limit (which is 100 times less than that causing toxic reactions). Current regulations state the limit to be 20 ppm, ie, no more than 20 mg total heavy metals per kg of material.

The required limit test for heavy metals in the US and European Pharmacopeias is provided to demonstrate that the content of metallic impurities that are coloured by hydrogen sulfide does not exceed the heavy metals limit. The test consists of two consecutive operations: preparation of the test solution, and the colour development by reaction with hydrogen sulfide, followed by comparison of the colour obtained with that produced with standard metal solution.

It should be noted that this test depends on the operator’s visual determination that the colour developed in the test solution is no more than that for the standard solution, ie, it is a qualitative judgement that has a sensitivity of no better than 3 to 5 ppm. Consequently, if a test produces a very weak colour in the test solution, a conclusion will be reached that the test material “Contains NO heavy metals”. Many complementary medicines are tested by the colorimetric method and hence claim to be free of heavy metal contamination.

The relatively insensitive colour test is scheduled by the USP to be replaced in December 2015 by the current industry standard spectroscopic instrumental technique, which has a sensitivity of 0.01 ppm for each heavy metal.

Trammune PSK has always been tested by the modern spectroscopic technique to ensure that it conforms to the limits set by the TGA. Because of the sensitivity of the technique, trace amounts of lead and arsenic have been listed in the specifications.

Other commercials products derived from Trametes (Coriolus) versicolor contain traces of heavy metals when analysed using the spectroscopic technique, as follows:

Analysis of Products Containing Trametes versicolor (syn. Coriolus versicolor) Extracts

      Trammune Brand of PSK; label states that each capsule contains 500 mg of Trametes versicolor Proteoglycan Concentrate. “Trammune-PSK”
      Mushroom Science Coriolus Super Strength; label states that each capsule contains 600 mg of Coriolus versicolor mushroom, hot water extract (40% polysaccharide). “MS Coriolus SS”
      Mushroom Science Coriolus PSP; label states that each capsule contains 400 mg of Coriolus versicolor mushroom, hot water extract (28% polysaccharide). “MS Coriolus PSP”
      Bell Lifestyle Products Supreme Immune Support #52; label states that each capsule
      contains Coriolus versicolor extract 1,500 mg (whole). “Coriolus BE”
      Planetary Herbals Full Spectrum Coriolus; label states that each tablet contains Coriolus versicolor Fruiting Body Extract (50% polysaccharides) 2 g. “Coriolus PL”


Capsule and Tablet contents were tested for heavy metal contamination by emission spectrometry
elemental analysis. The arsenic, lead and mercury content is reported in parts per million (ppm) in
the Table. Reference – National Measurement Institute Report RN0968586 dated 26 April 2013.

Metal Trammune-PSK MS Coriolus SS MS Coriolus PSP Coriolus BE Coriolus PL
Arsenic 0.13 0.77 1.1 0.048 0.75
Lead 0.11 0.40 0.30 0.037 0.30
Mercury < 0.01 < 0.01 < 0.01 < 0.01 < 0.01

All products are within the specifications defined by the TGA, viz, arsenic < 1.5 ppm, lead < 10 ppm, mercury < 2 ppm, although several are close to the limit for arsenic.

Traces of heavy metals can be found in most commercial products, but whether they are detected
depends on the method used to analyse for them. Methods described in the Pharmacopoeias currently
are far less sensitive than modern spectroscopic analysis can achieve. Products claiming to be free
of heavy metals have not been analysed by modern spectroscopic analysis.

Douglas Moore MSc PhD
Analytical Director
Committee Member 2003-2008
TGA Complementary Medicines Evaluation Committee

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