Medicinal Mushrooms

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© 1986 - excerpt from Medicinal Mushrooms

Modern Uses of Medicinal Fungi

http://www.christopherhobbs.com/

 

Far from being curiosities of the past, medicinal mushrooms are gaining an

ever-wider popu-larity today. This new interest has been greatly stimulated by

the large number of scientific studies that have been conducted on medi-cinal

mushrooms.

 

These modern studies have confirmed the tradi-tional uses of many fungi and have

even found new applications for them in some cases. Let's take a brief look at

some of the findings. For complete summaries, see the monographs on individual

species in the materia medica section.

 

Scientific Findings with Medicinal Fungi

 

One of the key results that has come out of both laboratory and human clinical

studies conducted on fungi is that a number of compounds in fungi can stimulate

immune function and inhibit tumor growth.

 

In particular, compounds called polysaccharides, which are large, complex

branched chain-like molecules built from many smaller units of sugar molecules,

have been intensively studied since the 1950s.

 

Again and again they have been shown to have antitumor and immunostimulating

properties, not only from many of the medicinal mushrooms reviewed in this book,

but also from lichens (such as usnea), bacteria, and even from the cell wall of

a yeast (called zymosan) (Chihara et al, 1970b).

 

mannose

galactose

xylose

fucose

+18-38% protein co-valently bound

 

 

Fig. 7: High-molecular weight heteropolysaccharides

 

 

 

Recently, German researchers have demonstrated that immune-activating

polysaccharides similar to those found in many fungi are also found in higher

plants, such as the widely popular Echinacea, and Astragalus, an important

Chinese herb (Wagner and Proksch, 1985).

 

These giant molecules are similar to ones found in the cellular membranes of

bacteria, and thus may " fool " our immune system into mounting an immune response

to them, while posing no actual threat.

 

This response has been shown to activate a variety of immune effector cell

responses, including an increase in macrophage and killer T-cell activity.

 

Since these het-eropolysaccharides are considered to be among the most important

of the active compounds in medicinal mushrooms, it is useful to look at them in

closer detail for a moment.

 

In fungi, polysaccharides are often molecularly bound to various proteins.

Proteins are molecules that closely represent the unique identity of organisms,

and thus often activate the immune system as they enter the body. They can

sometimes initiate an immune response which does not act as a beneficial

stimulant or tonic but can induce a powerful immune overreaction-leading to an

allergic response, for instance as in casein from milk products or gluten from

wheat or grass pollens. This response can even be life-threatening, such as in a

bee or wasp sting.

 

I know of no reported cases of people having such extreme immunological

responses to proteins in the medicinal mushrooms covered in this book; however,

some people are known to have idiosyncratic (highly individualized) reactions to

such usually safe mushrooms as Boletus edulis. It is unknown what the allergenic

compound(s) are. On the flip side, a number of mushrooms are said to increase

the beneficial immune-activating response of the body.

 

There are several questions that come up when one considers exactly what role

the polysaccharides or protein-bound polysaccharides play in the overall

benefits ascribed to the herbs and mushrooms that contain them.

 

Many existing scientific studies on medicinal mushrooms and their active

com-ponents are performed with test animals such as rats and mice, where

extracts of various kinds are injected, rather than given orally. It is

pertinent to ask how this applies to humans using fungi for food and medicine.

 

Do the polysaccharides, which are large molecular weight molecules, make it past

the highly acidic environment of the stomach and the alkaline environment of the

duodenum?

 

Do the polysaccharides work when taken orally, or do they have to be injected?

 

Also, when a tincture is made from the mushrooms (extracted with alcohol and

water), how does the alcohol affect the polysaccharides or proteins?

 

Are they destroyed by the alcohol, or partially broken down so that their

activity is reduced? What aspects of the immune system do they activate (T-cell

function and growth, macrophage activity, etc.), and how long does the activity

last?

 

While we do not know all the answers to these questions, there is some evidence

to support the positive activity of polysaccharides orally, and a low (below

25%) percentage of alcohol does not seem to destroy all their beneficial

effects.

 

For instance, the world's oldest echinacea product that is still manufactured

today is made from the freshly-pressed juice of Echinacea purpurea (L.) Moench

and then stabilized with about 24% ethanol.

 

Because no other active compounds have been demonstrated (such as alkylamides),

the manufacturer points to the polysaccharides as the immune-acti-vating

principle.

 

Other studies have shown that while very large molecular-weight polysaccharides

(about 800,000) activate a wide variety of immune functions, after reducing the

size of the molecules by heating, the range and strength of the activi-ty is

proportionately reduced (Adachi, 1990).

 

Small compounds with a molecular weight of about 6400 show only the ability to

activate glucose consumption (possi-bly lowering blood glucose) and synthesis of

lysosomal enzyme (an anti-bacterial protective function).

 

Various polysaccharides and protein-bound polysaccharides (i.e. they occur

nat-urally bound to protein molecules) have shown strong antitumor and

immune-enhancing effects.

 

I have summarized a number of representative studies about active

polysaccharide-containing fractions from medicinal mushrooms in Table 4. More

detailed information can be found in the individual monographs.

 

Table 4

 

Polysaccharide/ Protein Activity Subjects Ref.

 

Shiitake Lentinula edodes lentinan (a polysaccharide containing no protein; must

be administered by injection) accelerates dengeneration of tumor cells;

increases T-lymphocytes; improves health of chronic hepatitis patients; inhibits

HIV virus; benefits AIDS patients animals & humans

 

animals

 

humans Kosaka,1986;

 

 

Liu,1987;

 

Liu,1987;

Iizuka,1988,

1990a,b

LEM (a protein-bound polysaccharide) benefits chronic hepatitis sufferers liver

protectant, anti-viral, and immune stimulating humans

 

animals Izuki,1986;

 

Mizoguchi,1987b;

Lin,1987;

Aoki,1984a

Turkey Tail Trametes versicolor psk/krestin (a water-soluble, protein-bound

polysaccharide) inhibits binding of HIV with lymphocytes immunopromoter

antioxidant activity in vitro

 

animal

 

animal Tochikura, 1987a

 

Zhu, 1987

 

Nakamura, 1986

 

interferon and antitumor activity animal many chronic ailments improved with

administration orally and by injection cancer patients show increased human life

span human Ebina, 1987a

see monograph p. 161

 

Oyster Mushroom Pleurotus ostreatus (Jacq:Fr.) Quél

acidic polysaccharide fraction polysaccharide 95% tumor inhibition rate against

sarcoma-180 from doses of 5 mg/kg 4% addition to a normal diet was found to

lower serum and liver levels of cholesterol after 2 months' feeding animal

 

animal Yoshioka, 1972

 

Bobek, 1991b

Hen of the Woods Grifola frondosa Fraction-D etc. from Grifola tumor growth

inhibition, orally animal Nanba, 1993s

 

 

Of course polysaccharides are not the only active constituents found in fungi,

nor do they show only antitumor activity.

 

Smaller compounds, such as terpenes and steroids, have also been found, and some

of these have shown antitumor activi-ty.

 

And a great number of polysaccharides and protein-bound polysaccharides have

been shown to have antibiotic and antiviral properties, as well as the ability

to lower blood pressure and reduce blood levels of lipids (that is, fatty acids)

and sugar (Lindequist, 1990).

 

These active compounds make many fungi useful for treating infections, flu,

diabetes, heart conditions, and perhaps even AIDS.

 

Following is a summary of research on the three fungi discussed above in the

section on Chinese medicine.

 

These fungi are by no means the only ones studied, but two of them, ling zhi or

reishi (Ganoderma lucidum) and shiitake (Lentinula edodes), are perhaps the

best-known and most extensively studied mushrooms in the world.

 

For more complete information on their chemistry and pharmacology, as well as

literature references to document all of the uses, please refer to the

mono-graphs in the second half of this book.

 

REISHI - LING ZHI

 

In numerous clinical trials conducted on humans over the last 20 years,

Ganoderma lucidum has been used to treat a wide variety of disorders, including:

 

neurasthenia, dizziness, insomnia, rhinitis, and duodenal ulcers

retinal pigmentary degeneration, leukopenia, progressive muscular dystro-phy,

and osteogenic hyperplasia

mental disease caused by environmental stress, Alzheimer's disease,

hyper-lipidemia, and diabetes

hepatitis and symptoms associated with anorexia

high-altitude sickness (by oxygenating the blood)

 

Of special note are reishi's action on the heart and lungs.

 

In patients with coro-nary heart disease and hyperlipidemia, reishi has been

studied for its ability to alle-viate symptoms such as palpitations, dyspnea

(sudden difficulty in breathing), pre-cordial pain, and edema, and it seems to

lower blood cholesterol and blood pres-sure.

 

G. lucidum has also been used to treat heart arrhythmias.

 

As for reishi's effect on the lungs, in one study of over 2,000 patients with

chronic bronchitis, reishi brought about marked improvement in 60-90% of the

patients.

 

The older patients, especially, seemed to benefit the most (Chang & But, 1986).

Bronchial asthma has also been reported to respond well to treatment with G.

lucidum, as do several other allergic diseases. Although the antiallergic

compounds in G. lucidum are not yet clearly understood, scientists have shown

that G. lucidum inhibits the release of histamine, a compound that causes blood

vessels to dilate and is responsible for swelling, inflammation, and other

allergic reactions.

 

CORDYCEPS

 

DONG CHONG XlA CAO

 

In the clinic, C. sinensis has been studied for the treatment of chronic

obstructive liver disorders, high cholesterol, and other aging disorders,

including loss of sexual drive, and has shown positive effects. C. sinensis has

also been reported to be effec-tive in the treatment of heart arrhythmias, lung

carcinoma, and chronic nephritis and kidney failure.

 

SHIITAKE

 

Note: " The shiitake mushroom is now Lentinula edodes; this separates it from a

number of other Lentinula spp. that are not closely related. DNA studies support

this separation. Many other Lentinula species are more closely related to the

genus Polyporus (Arora, 1994). "

 

Two types of shiitake preparations have been studied extensively: lentinan, an

active polysaccharide extracted from the fungus, and an extract preparation of

the mycelium of Lentinula edodes called LEM (an acronym for " Lentinula edodes

mycelia " ). In animal studies, lentinan and/or LEM have shown antitumor and

antiviral activity, and a distinct stimulation of killer T-cells, which are

involved in the immune response. They have also stimulated the production and

function of white blood cells, as well as the production of both antibodies and

interferon (an antiviral protein), while they have inhibited the synthesis of

prostaglandins, which are locally-acting hormones that regulate blood vessel

size, mediate inflammation (a protective immune response) and smooth muscle

reactivity. Another active con-stituent of shiitake, eritadenine, may lower

levels of cholesterol in the blood (Yamamura and Cochran, 1974a). Table 5

summarizes the important potential uses of shiitake based on studies

conducted on both animals and humans.

 

Table 5:

Summary of Research on Shitake

 

ACTION

TYPE OF TEST EXTRACT OR FORM DOSE (AMOUNT, ORAL OF IV) REFERENCE

 

Antitumor In vivo- Mice Lentinan 10 doses of 1 mg/kg body weight (i.p.) Chihara

et al. 1970 b

 

Antiviral In vitro- Mice LEM Cultured Mycelia 10 mg/ml Sormiachi et al. 1990

Fujii et al. 1978

 

Immune enhancement In vivo- Mice Culture cells i.p. Zheng et al. 1985

Lowers blood pressure & cholesterol in vivo- human Shiitake powder Oral Kabir et

al, 1987

 

Protects liver from immunological damage In vitro LEM Animals Mizoguchi et al

1987

 

Helps produce antibodies to hepatitis B and improves liver function In vivo-

Mice LEM ------ Harada, 1987

 

Protects physically active people from overwork and exhaustion; builds vitality

in the elderly In vivo- Human Lentinan ------ Aoki, 1984b

 

Inhibits growth of HIV In vitro LEM 0.4mg/ml Tochikura et al., 1987 b

 

Redues bronchial inflammation In vivo- Human Fruiting body 6-16 g, dry Liu and

Bau, 1980

 

Regulates urinary Incontinence In vivo- Human Fruiting body 6-16 g, dry Liu and

Bau, 1980

 

Anti-cholesteremic In vivo- Human Fresh dried 90g/day

9g/day Suzuki & Oshima, 1974

 

 

In human clinical trials, lentinan has shown antitumor activity and has been

reported to increase the survival rate and length of life of women with various

can-cers in hundreds of patients (Aoki, 1984).

 

Today it is commonly used for treating cancer, often in conjunction with

chemotherapy.

 

It has also been reported to be useful in treating chronic hepatitis and

pulmonary tuberculosis, as well as gastric cancer, pancreatic cancer, leukemia,

lymphosarcoma, and Hodgkin's disease

 

LEM has inhibited HIV infection of cultured human T-cells in vitro and in

clin-ical trials (Iizuka, 1988, 1990a,b).

 

A symptomatic patient with antibodies to the AIDS virus and a T4 cell count of

1,250/mm3 was given a freeze-dried tea of shiitake mycelium orally at 6 g/day.

 

The T4 cell count improved to 2,045 after 30 days and 2,542/mm3, and the

symptoms were much improved after 60 days.

 

The extract also inhibited the production of AIDS virus particles by infected T4

lymphocytes in vitro and increased the production of interleukm 1 by peritoneal

macrophages.

 

LEM may also be beneficial for non-insulin-dependent diabetics because of its

reported ability to lower blood sugar levels.

 

In Japan, lentinan is currently classi-fied as a drug, while LEM is considered a

food supplement.

 

Note that LEM or other concentrated extracts are probably preferable to raw

shiitake for medicinal purposes because they are more concentrated and are

easily absorbed in the diges-tive tract, but using the mushrooms in cooking and

in teas may also be effective.

 

It is known that large overdoses of 10 to 50 times the normal clinical dose can

lead to immune suppression, or it simply will not have any immunopotentiating

effect.

Otherwise, side effects are few, except for skin rashes that clear up shortly

after dis-continuing the extract.

_________________

 

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