Understanding Mushroom Products

 

As well as having a large number of mushrooms with often similar properties to choose from, there is also an often bewildering variety of product forms produced through different growing and manufacturing processes.

Whereas traditionally only the fruiting body, or in some cases the sclerotium (underground hyphal mass - ie. Polyporus umbellatus and Poria cocos) or conk (sterile fungal growth on the trunk of the tree - ie. Inonotus obliquus - Chaga), was harvested and either been consumed whole in food, as with Lentinus edodes (Shiitake) and Grifola frondosa (Maitake), or as a teas made from aqueous decoctions of the fruiting body, as with Ganoderma lucidum (Reishi) and I. obliquus, nowadays many commercial mushroom products are produced from the mycelium of the mushroom grown either by liquid state fermentation or solid state fermentation (biomass).

The following overview summarizes the features of the different dosage forms available.

Fruiting Body/Conk/Sclerotium

The traditional dosage form of medicinal mushrooms, the fruiting body typically contains a higher level and number of different polysaccharides than the mycelium or culture broth with a beta glucan content of 41% reported for G. lucidum fruiting body by Stamets¹. A higher level of water soluble polysaccharides is also reported in the conk or sclerotium of fungi such with I. obliquus with the conk having 176.5g/kg (dry weight) soluble polysaccharides and the mycelium having 53.9g/kg (dry weight)².

Research with beta-glucans from L. edodes and G. frondosa showed an increase in concentration with fruiting body growth until an optimum size was reached (approx. 17g for L. edodes and 180g for G. frondosa), after which levels declined³.

In addition, concentrations of components such as triterpenes (G. lucidum) and other phenolic compounds (I. obliquus) tend to be higher in the fruiting body, where their bitter taste and natural anti-microbial properties act to discourage unwanted predators. Data from Antrodia camphorata suggest that the level of triterpenes in the mycelium is 40% of that in the fruiting body and for many biomass products the relative discrepancy is likely to be larger owing to the presence of residual substrate in the biomass (less than 100% of the biomass is mycelium).

Extracts

For mushrooms where triterpenoid and other phenolic components are therapeutically important, i.e. A. camphorata, G. lucidum, I. obliquus, products derived from the fruiting body/conk are usual with, given their indigestible nature, extracts often used in agreement with traditional practice.

Extracts can also be used to deliver high concentrations of polysaccharides or other active components. They are usually made from either the fruiting body or the mycelium through one of two main methods:

• Aqueous extraction (traditional teas/decoctions) gives high polysaccharide concentrations but low levels of poorly water-soluble triterpenes. Crude polysaccharide extracts typically have around 30% polysaccharides with further purification possible.
• Ethanolic (alcohol) extraction (traditional tinctures) extracts more triterpenes but fewer polysaccharides (ethanol precipitates the polysaccharides out of solution).

As well as offering higher concentrations of polysaccharides and other clinically important compounds, extracts may be preferred in cases of gut dysbiosis, from antibiotic use or otherwise, with resultant impaired ability to break down whole mushroom or biomass products (also in cases of colostomy).

For some mushrooms such as G.lucidum, aqueous extracts and ethanolic extracts can be combined to deliver high concetnrations of both polysaccharides and triterpenes. Some practitioners such as Nanba have also reported good results from combining high concentration polysaccharide (beta-glucan) extracts with whole mushroom fruiting body or biomass⁴.

Spores

The fruiting body exists to spread the spores of the mushroom and some products use the spores themselves. Together with polysaccharides, triterpenes and sterols the spores are rich in fatty acids, which have been implicated in their therapeutic action^5-7. However, studies comparing the activity of G. lucidum spores and unpurified fruiting body show little difference⁸.

Mycelium (liquid/submerged fermentation)

Liquid state fermentation is the same technology used in the pharmaceutical industry to produce antibiotics and also to produce other industrial products such as fungal enzymes. The mushroom mycelium is cultured in a closed vessel with a liquid substrate containing all the essential nutrients for growth and growth parameters such as nutrient composition and temperature carefully controlled to optimise concentration of the desired components.

Because the substrate is a liquid the mycelium can easily be harvested and then either used as a therapeutic component itself or in most cases further processed to yield various extracts (eg. PSK and Lentinan). In addition the extracellular metabolites secreted into the growth medium (broth) may also be harvested for their therapeutic properties (eg. Schizophyllan, an extra-cellular polysaccharide from Schizophyllan commune).

Mycelial Biomass (solid state fermentation)

In solid state fermentation (often referred to as biomass production) the mushroom culture is inoculated into a sterile, grain based substrate, usually brown rice, and left to fully colonize the substrate. At the point at which it has exhausted the capacity of the substrate to support further growth and is about to produce fruiting bodies (primordia stage) the resultant mass of mycelium and residual substrate is dried and granulated to make a powder, which is then usually made into tablets or encapsulated.

As well as mushroom mycelium and some residual grain, biomass products contain the full range of metabolites excreted into the substrate by the mycelium (especially antibiotics and exopolysaccharides), together with a wide variety of enzymes, including digestive enzymes (proteases, lipases etc.) and anti-oxidant enzymes (laccase, catalase and superoxide dismutase). They also contain substrate breakdown products such as arabinoxylans with therapeutic properties in their own right. Indeed, in supplements such as Biobran, also known as MGN-3 (shiitake digested rice bran) and Avemar (yeast digested wheatgerm) the enzymatically transformed substrate itself is seen as the therapeutic entity. Stamets reports crude arabinoxylane content of mushroom mycelial biomass cultivated on short grain brown rice by his company, Fungi Perfecti, as ranging from 7.8% in Agaricus brasiliensis to 24% in Cordyceps sinensis.

While mushroom biomass products contain a wide range of bioactive molecules, levels of the key immunomodulating beta-glucans and related heteropolysaccharides are low. Stamets reports beta-glucan levels in the above form of biomass ranging from 1.23% in Hericium erinaceous to 2.96% in I. obliquus with A. brasiliensis 1.83%, G. frondosa 2.51% and G. lucidum 2.19%. At the same time he reports the beta-glucan content in mushroom fruiting bodies as varying from 8.9% in A. brasiliensis to 14.5% in G. frondosa and 41% in G. lucidum¹.

These figures for beta-glucan concentrations in biomass products are consistent with those obtained by the author on biomass samples from other manufacturers.

Combination Products

There is evidence that combinations of mushrooms can have a greater effect on the immune system of both humans and mice than single mushrooms. Ghoneum et al reported synergistic action between different mushrooms and, in a 2002 paper, Sawai et al report greater immunological activity with higher levels of macrophage activation and INF-y induction by a mixture of mushroom polysaccharide extracts^9,10. Stamets also reports a blend of seven mushrooms (biomass) as having enhanced NK cell activation in human spleen cells when compared to the individual mushrooms¹¹.

 

 
1. Potentiation of cell-mediated host defense using fruitbodies and mycelia of medicinal mushrooms. Stamets P. Int J Med Mushr. 2003;5:179-191      

2. Higher Basidiomycota as a source of antitumor and immunostimulating polysaccharides (Review). Reshetnikov S.V, Tan K.K. Int J Med Mushr. 2001;3(4):361-394

3. Changes in immunomodulating activities and content of antitumor polysaccharides during the growth of two medicinal mushrooms, Lentinus edodes (Berk.) Sing, and Grifola frondosa (Dicks.: Fr.) S. F. Gray. Minato K.I, Mizuno M, Kawakami S, Tatsuoka S, Denpo Y, Tokimoto K, Tsuchida H. Int J Med Mush. 2001;3(1):1-8
4.  Maitake extracts and their therapeutic potential - A review. Mayell M. Alt Med Rev, 2001;6(1)
5. Antitumor activity of the sporoderm-broken germinating spores of Ganoderma lucidum. Liu X, Yuan J.P, Chung C.K, Chen X.J. Cancer Lett. 2002;182(2):155-61.
6. Sterols and triterpenoids from the spores of Ganoderma lucidum. Zhang C.R, Yang S.P, Yue J.M. Nat Prod Res. 2008;22(13):1137-42.
7. Chemical constituents of the spores of Ganoderma lucidum. Zhang X.Q, Pang G.L, Cheng Y, Wang Y, Ye W.C. Zhong Yao Cai. 2008;31(1):41-4.
8. Comparative studies on the immunomodulatory and antitumor activities of the different parts of fruiting body of Ganoderma lucidum and Ganoderma spores. Yue G.G, Fung K.P, Leung P.C, Lau C.B. Phytother Res. 2008;22(10):1282-91.
9. Immunomodulatory and anticancer effects of active hemicellulose compound (AHCC). Ghoneum M, Wimbley M, Salem F, McKlain A, Attalah N, Gill G. Int J Immunotherapy. 1995;1,1:23-28
10. Extraction of conformationally stable (1-6)-branched (1-3)- β-glucans from premixed edible mushroom powders by cold-alkaline solution. Sawai, M., Adachi, Y., Kanai, M., Matsui, S. and Yadomae, T. Int J Med Mushr. 2002;4:3
11. Potentiation of cell-mediated host defense using fruitbodies and mycelia of medicinal mushrooms. P.Stamets. Int J Med Mushr. 2003;5:179-191