Bioactives of Reishi
Research suggests that Reishi’s bioactive constituents are in particular therapeutically effective when they can benefit from each other’s presence; the so-called synergistic effect.
A full-spectrum product will contain all bioactives, but in order to benefit from their therapeutic potential this full-spectrum product should be an extract. The majority of the bioactives are embedded in the indigestible chitin cell-walls of the mushroom, not in the cell itself, like with most herbs. Extraction is essential to break the cell-walls and set the bioactives free from their chitin chains.
Reishi’s main bioactive ingredients and their assumed therapeutic effects
- Polysaccharides
Like almost all medicinal mushrooms, Reishi’s main bioactive ingredients are water-soluble (1>3)(1>6) beta-D-glucans, which are part of the polysaccharide fraction. (
all beta-glucans are polysaccharides, but not all polysaccharides are beta-glucans!!). Research shows that these glucans are in particular responsible for the immune-balancing effects. Hot water extracts contain bioavailable polysaccharides; depending on the quality of the source material and the extraction procedure polysaccharide percentages of up to 50% can be achieved.
Apart from those, polysaccharides linked to proteins and peptides (proteoglycans, peptidoglycans, glycopeptides etc.) have also been isolated, similar to the bioactive PSP and PSK fractions found in Coriolus versicolor (Turkey Tail). These particular bioactives are only present in dual extracted Reishi.
It should be noted that the amount of bioactive water-insoluble polysaccharides was found to be higher than that of water-soluble polysaccharides. This proves again the importance of dual extracted Reishi – only the combination of ethanol and hot water extraction (in a multi-step process) can guarantee that all bioactives, both solubles and insolubles, are present.
Scientific investigations concerning the anti-tumour and immuno-modulating activities of both the beta-glucans and the linked polysaccharides were reported as early as in 1957.
- Triterpenes
What sets Reishi apart from other mushrooms is the enormous variety of triterpenes, which give the mushroom its distinct, intensely-bitter taste (which is considered a quality marker). Over 150 triterpenes have been identified so far.
A whole group, known as ganoderic acids, is only found in Reishi and other species of the Ganoderma family. All of these have therapeutic potency. It is believed that these triterpenes in particular are responsible for the lipid-lowering and anti-oxidant effects, which are enhanced synergistically by the polysaccharide fractions.
Triterpenes are also considered to be potential anti-cancer agents due to their – in vivo and in vitro – activity against growing tumors: they have direct cytotoxicity against tumor cells rather than triggering the immune system, like beta-glucans do.
Furthermore, Reishi triterpenes inhibited HIV-1 protease and HIV-2 protease. Hepatoprotective effects were also found (in vivo and in vitro).
Triterpenes are only present in dual extracted Reishi products, because they are all non-water soluble and oily. As said, the yield of triterpenes in Reishi is very low and this makes supplements with a high percentage of pure triterpenes exceptionally expensive.
Percentages can be as high as 18%(excluding spore products). However, triterpenes are not easily absorbed in our body when taken orally; their bioavailability is low. For a supplement producer it is essential to find the proper balance between high percentages of triterpenes and polysaccharides and bioavailability.
- Nucleosides, minerals and trace elements
Just like Cordyceps sinensis Reishi also contains bioactive nucleosides, like adenosine, uridine and guanosine. These affect e.g. blood clotting and improve the ability to of the red blood cells to absorb oxygen.
The nucleosides are found in particular in the fruiting body in the area around the spore producing tubes (the hymenophore tissues). Many Reishi producers are mentioning ‘large‘ amounts of e.g. adenosine when marketing their products, but our research showed only 0.08 mg/kg (or 0.000008%), which is just a trace and much lower than what is found in Cordyceps sinensis (the ORIVeDA Cordyceps extract contains e.g. 0.7% adenosine -batch 130322-). Mycelia appear to have no detectable levels of nucleosides.
Reishi is also rich in minerals and trace elements; it has ± 10% of mineral content with potassium, calcium, and magnesium as the major components.
Some sources are emphasising the presence of organic germanium in Reishi. Although germanium is not an essential element it has been credited with immunopotentiating, antitumor, anti-oxidant, and antimutagenic activities at low doses. However, there is no firm evidence linking this element with any of the specific health benefits associated with the mushroom. It is present in trace amounts only.
Bioavailability
It is important to realise that the majority of these bioactives will only have a therapeutic effect when they are part of a properly extracted Reishi product.
This absolutely essential part is known as ‘bioavailability’ (meaning: can we actually absorb and thus benefit from the product, therapeutically speaking). ‘Properly extracted‘ meaning a two, or, even better, a three step extraction procedure, with ethanol, hot water and alcohol precipitation included.
Unlike e.g. Chaga the yield of bioactives (in particular triterpenes) in Reishi is very low. Labor intensive (and therefore expensive) extraction procedures are needed to improve the yield and to create a full-spectrum product with both a high level of purity and a high percentage of bioactives.
The majority of Reishi products on the market are either non-extracted or just basic hot water extracts. They are easy to spot if you know what to look for: the supplement facts label gives either no indication of the bioactives (no percentages of polysaccharides, etc)or only states something like ‘10:1 extract‘ – which is meaningless as a quality marker. ‘Extract‘ is in general the wrong term here; ‘concentrate‘ would be more accurate, since most of the time it only indicates a reduction in weight or volume.These ratio-statements are impossible to verify by a third party and do not reveal anything about the bioactives that are present.
Traditionally, the dried fruiting body of Reishi was cut into long narrow strips, which were then used to make tea.
