Nutritional and Medicinal Values of mushroom
Today, the popularity of mushrooms is due not only to their culinary value but also to their potential as a source of protein that can enrich human diets especially in some developing countries where meat may be rare and expensive. Mushrooms contain more protein than either fruits or vegetables.
They can be eaten, as they are cooked or raw, unlike other protein sources such as soya. Mushrooms are also low in cholesterol. Besides their protein content, mushrooms are also high in certain vitamins such as B, C, D, riboflavin, thiamine, and nicotinic acid. Mushrooms are also a good source of iron, potassium and phosphorus in addition to folic acid, an ingredient known for enriching the bloodstream and prevention deficiencies.
Proximate protein content (dry weight) of edible mushrooms as reported by different authors.
Species Protein content (%)
Volvariella volvacea : 21.32
Agaricus bisporus : 27.8
Pleurotus ostreatus : 27.4
Pleurotus florida : 37.19
Pleurotus sajor-caju : 36.94
Lentinula edodes : 17.5
Auricularia auricular-judae : 8.1
Flammulina velutipes : 21.9
Medicinal Importance of Mushrooms
The invention of the so called “wonder drug” penicillin was a landmark in the field of medicinal uses of fungi. Since then several fungi have been well recognized for their antifungal, antibacterial, antiviral, antitumour and many others such properties of pharmacological values. In the recent past a variety of medicinal preparations in form of tablets, capsules and extracts from mushrooms have been produced and marketed.
Mushrooms are perhaps the only fungi deliberately and knowingly consumed by human beings and they complement and supplement the human diet with various ingredients not encountered in or deficient in food items of plant and animal origin. Besides, chemical composition makes them suitable for specific group suffering with certain physiological disorders or ailments. Mushrooms are regarded as an ultimate health food, low in calories due to presence of good amount of quality protein, iron, zinc, vitamins, minerals and dietary fibres which protects from digestive ailments and strengthening of the human immune system.
Recent investigations have proved the empirical observations of the oriental herbalists that certain mushroom possesses very useful medicinal attributes. In the 1991, the value of world medicinal crops was estimated at 8.5 billion dollars and in the same year 1.2 billion dollars are estimated to have been generated from medicinal products from mushrooms. This was based on the sale value of products from Coriolus, Ganoderma, Lentinula, Schizophyllum and other mushrooms.
Although the biggest use of mushroom has traditionally been for reasons of their gastronomic and nutritional appeal. There has always been interest in certain mushroom for their medicinal attributes. Production of medicinal mushroom is now a days increasing over world wide. In the present era a variety of proprietary product based on mushroom nutriceuticals and pharmaceutical have already been produced and marketed.
Various mushrooms and their metabolic extract have been reported to protect against cancer, tumor and pathogenic microorganisms. It is suggested that regular consumption of different mushroom varieties not only protects humans from heart trouble but also had medicinal potential for certain ailments.
Important Medicinal Mushrooms
Mushroom have a long history of use in traditional Chinese medicine . In fact it is estimated that in China more than 270 species of mushrooms are believed to have medicinal properties with 25% of them thoughts to have antitumour capability. Few of the edible mushrooms have also gained importance in modern medicine for their various pharmacological values. The details of medicinally important mushrooms are summarized as follows.
Ganoderma lucidum (Reishi mushroom):
Ganoderma lucidum (Ling Zhi or Reishi in Chinese ,Saruno ,Koshikake or Mannendake in Japanese), belonging to higher Basidiomycetes has been used extensively as “mushroom of immortality” in China and other Asian countries for 2000 years. It is full of medicinal compounds and is said to promote a healthy heart as well liver .
Reishi is also believed to be a powerful anticancer agent. It is used in Chinese medicine for its immunogenic, antibacterial and anti-inflammatory properties. It demonstrates its antitumor and immunomodulatory activity by increasing bodily resistance against the growth of tumors. It can also act as a metabolic regulator.
Two main classes of compounds present in Ganoderma have been found to have pharmacological activities : Triterpenes and Polysaccharides. Anti-tumor property of G. lucidum is due to polysaccharide (referred as GP, Ganoderma polysaccharide).These polysaccharide especially the β- glucans fraction have been found to have broad stimulatory effects on white blood cells. These effects may ultimately lead to the release of cytokines and lymphokines which produce antitumor and other effects.
The triterpines have been tested and found to lower blood pressure to be beneficial as anti-inflammatory and as antiviral. Nature health practitioner in the west are beginning to use Reishi for its sleep promoting effects .Compound called tri-terpenes are thought to be responsible for producing a calming effect on the nervous system. In recent years this mushroom has got immense fame due to its wide medicinal use. It is cultivated in China, Japan and also found throughout India as stem parasite of several trees.
This fungus is called “turkey tail” in English. Probably because it has multi-colored fruiting bodies which grow in overlapping clusters on rotten wood of broad leaf trees and occasionally on trunks of pine. It is known in Chinese as Yun-zhi. Traditionally it is used as a tea or a dried powder to treat infection or inflammation of the respiratory, urinary and digestive tracts, liver diseases, general weakness and tumors.
Coriolus versicolour also known as Trametes versicolour , is a common non edible polypore which has been found to produce polysaccharides commercially known as Krestin or PSK as anti tumor agent .It is a protein bound polysaccharide that is obtained as a hot water extract from the mycelium of Coriolus versicolour. This protein bound polysaccharide (PSK or PSP) is a biological response modifiers (BRM), which is capable of modifying the host’s biological response by stimulating the immune system and thus exhibiting diverse therapeutic effects, particularly antitumor activity.
Grifola frondosa (Maitake):
This species is found in the part of the Eastern U.S, Europe and Asia. In Japan it is called as Maitake, which means “dancing mushroom”. G. frondosa is another mushroom which is highly effective in controlling blood pressure, diabetes and constipation. Maitake prevents the destruction of HIV-T-Helper cells. A patients T-helper cells count is measured to trace the progression of HIV to AIDS.
Lentinula edodes (Shiitake):
L. edodes can be considered as leader of mushroom which can be used both for edible and medicinal purposes. It is known as Xiang gu in China, which means fragrant mushroom probably due to its characteristics flavour and shiitake in Japan, which derives its association with the shiia tree. The shiitake (Lentinula) is the most popular edible mushroom in Japan. The Asians have used it for thousands of year as a tonic and stimulant to increase vitality, prevent cerebral hemorrhage strokes, as well as improve circulation.
L. edodes is source of the well known antitumor polysaccharides lentinan from the fruiting body or mycelia. Lentinan is highly purified, high molecular weight polysaccharide which does not attack cancer cells directly but produces its antitumor effect by activating different immune response in host. In Lentinula edodes, an active hypo-lipidemic substance identified as eritadenine is found to exhibit a general response affecting cholesterol, triglyceride and phospholipid level. Lentinan is being studied not only for its antitumor properties but also for its ability to lower cholesterol and blood pressure.
Cordyceps species (Keera ghas):
Cordyceps an extremely rare mushroom is a native of high Himalayan Mountain. It can be found for a short time each summer, growing on its natural host, a caterpillar. Recent evidence has shown that the extract of C. sinensis has immunoregulatory activity. One of the most valued traditional Chinese medicine is used commonly for the replenishment of body health consists of the dried fungus C. sinensis growing on Lepidopteran (caterpillar) larvae. For medication the fruiting body (fungus) and the worm (caterpiller) are used together.
The fruiting body and its caterpillar host shows close resemblance in main constituents and antioxidation activity and the result suggest that the function of the worm in Cordyceps is to provide a growth medium for the fruit body.
It is believed to be sweet in taste, mild and non-toxic. It is used as a cough syrup for treating chronic tracheitis and other cough related conditions. It is able to help strengthen the vital internal organs such as sex organs, kidney, lungs and stomach and treat ulcers. It is also used as antipyretic agent and immune tonic.
It is said to enhance beauty and gonadal activity. It is useful for weakness after child birth, constipation, abnormal menstruation, dysentery and gastritis. T. fuciformis contains acidic polysaccharides which show anti-tumor activity and enhance immune functions. It has cholesterol lowering effect attributable to the suppression of absorption of cholesterol from the digestive tract.
It is considered as mild sweet and bland. It is used to cure edema and clear febrile illness. The cortex of sclerotium of this mushroom is used as a diuretic and a decoction for cough whereas the internal white portion is used to relieve uneasiness arising from pregnancy and the heart discomfort. The polysaccharides of this fungus such as spachyman and pachymaran exhibit strong antitumor and immuno-modulatory activities. The low molecular weight tetracyclic triterpenes have immuno-stimulating and antiviral activities.
Pleurotus species (Oyster or Dhingri):
Oyster mushroom is the third most popularly grown mushroom in the world and ranks second in India. In India Pleurotus sajor-caju is one of the commonly growing species. Pleurotus sajor-caju has been shown to exhibit hypotensive activity, reduce the rate of nephron deterioration which may be useful for chronic renal failure patient. Oyster mushroom (Pleurotus ostreatus) has also been found to have hypocholesterolemic effects in rats. Pleurotus tuberregium also shows some antimicrobial activity