Chaga likes colder climates, so it can be found in the northern hemisphere on all continents. It is commonly found in Canada, Asia (Kazakhstan, Russia, China, Japan, Korea) and Europe. Chaga is also commonly found in our country, Kotlaba in his text from 1984 describes 93 localities with the occurrence of the fungus. 30 of them were in Bohemia, 30 in Moravia and 33 in Slovakia. The fungus can be found from the lower zones (from about 155 metres above sea level) to mountain areas. It has also been recorded in the Tatras.

It most often infects birch trees, but cases of Chaga being found on beech, oak or poplar trees have also been described. The spores formed by the sexual stage of the fungus cause white rot.

The fungus penetrates through wounds on the tree into the interior of the tree, spreads, but does not penetrate the surface of the tree for long. In this way, Chaga can survive in a living tree for decades (10-80 years). Eventually, it bursts out through the bark and forms a dark brown to black formation on the surface of the tree that has a cracked surface and resembles burnt charcoal. It forms 1-3 per trunk. However, if this black fungal part is cut away from the tree trunk, a yellowish to brown fungal part appears inside.

Chaga has two stages during its maturation from mycelium to fruiting body.

• The anomorphic stage (reproduces asexually, does not form chlamydospores or sporophores) is visible and permanent. It is the typical mass growing on the tree. As we have already outlined, it has a furrowed surface, brittle, dry, resembling "burnt" black coal.

• The sexual stage is white and forms when the host tree or part of it dies. It forms only once per infection cycle. It is a short-lived fruiting body that forms under the bark and then breaks through it. It is flat, thin and light brown on the surface of the tree. The consistency is cork-like and soft when fresh, becoming hard and brittle with age.

Since Chaga is mainly known in the Russian region, it is not surprising that the first modern 'manuals' on the collection, cultivation and quality control of Chaga (1985) came from there.

The recommendations state that

• Chaga should only be harvested from living trees to ensure its freshness, the potency of Chaga declines after a year of storage
• Small mushrooms should be left to grow
• Trees with Chaga should not be cut down to prevent collectors from reaching the mushrooms high on the trunks
• Chaga should be cut from the trunk and then the bark and wood removed
• Chaga should be dried immediately so that it has less than 14% moisture, the temperature during drying should be between 50-60 degrees Celsius.
• Chaga should be stored in a cool, dry place

Nowadays, of course, there is an effort to cultivate Chaga, which will increase its production but also protect wild trees from infection.

In Finland, it is grown in reserved forests, which have little use for forestry and must meet certain conditions, the number of trees per hectare, etc. The price of Chaga is between 50-100 €/kg. Dried, made into tea etc. it is worth between 130-320 €/kg. In Finland Chaga is popular in the form of tea. It is called Pakuri and its tea is called Tikka-tea.

Chaga can of course also be grown on different types of substrates. However, it is more complicated, and unless birch is added, Chaga is depleted of a very potent substance, i.e. betulin, which it can suck up from its host.

History of Chaga

Chaga, or rather its use, has a very long tradition. It has been mentioned since the times of Mesopotamia, ancient Egypt and China. From ancient China come herbals that mention Chaga, for example Shen Nung Pen Ts'ao Ching, i.e. Shen Nong Ben Cao Jing.

Apart from Asia, Chaga has been used since time immemorial, e.g. in the Siberian region, by the local Khanty/Oystaks. They used it not only for healing but also for shamanic rituals. They mainly used it to cure digestive problems, drinking drinks made from Chaga, and also smoked it, believing it to strengthen the lungs. It also found use as a 'soap' and helped to alleviate skin problems. Within Russian medicine, Chaga has been prescribed for various types of tumours since the 16th century. This is also due to the fact that as early as the 12th century, Prince Vladimir II Monomakh credited Chaga with the disappearance of a tumor he had on his lip. We are still in Russia, as Chaga is also mentioned by the very famous Russian writer Alexander Solzhenitsyn in his book. He devoted himself to it in a book called Cancer.

In Japan, Chagu was used by the Ainu people of Hokkaido, who made tea from it to cure stomach problems. They also smoked Chaga during religious ceremonies, filling their pipes with Chaga powder.

Nor were the natives of the North American continent unfamiliar with Chaga. Many Indian tribes (Chippewas, Ojibways, called Chaga Cha'a'ihtthi) are known to have worked with Chaga, again it was for healing or ceremonies.

If we now look more to the present and especially to scientific knowledge, we must begin in 1864, when the composition of Chaga was investigated by J. G. N. Dragendorff (1836-1898). He conducted experiments in St. Petersburg. At that time, however, he did not arrive at anything substantial. Chaga and especially its effects remained hidden until the twentieth century. Around 1950, clinical trials with Chaga began to be conducted at the Moscow Medical Institute and spread to other parts of Russia, as it began to be shown that Chaga was not just a placebo, but the results of its administration were evident. By 1955, Chaga was being studied more and more intensively, including at scientific institutions such as the Russian Medical Academy of Science. During the 1950s, standardized products containing Chaga, such as Befungin and Binchaga, were also created.

Today, Chaga is well known and available worldwide.

Composition of Chaga

Its popularity over many millennia suggests that its use has a beneficial impact on humans. Its effects are mainly based on its composition. Chaga contains a large number of bioactive substances.

Polysaccharides, sugars

Polysaccharides are the most abundant component of mushrooms, and this is no different for Chaga. It contains both storage and structural carbohydrates, i.e. they are part of the cell walls. There are single monosaccharides in Chaga, but also chained monosaccharides that form polysaccharides. The latter are represented by coarse fibre, which is non-absorbable, e.g. chitin, but is a source of nutrients for the intestinal microflora and promotes peristalsis. More important, however, are the polysaccharides that are absorbed from the intestine into the body. These include mainly beta-glucans, most commonly (1>3)(1>6) beta-D-glucans.

Also found in Chase were 1-6 alpha-galactan, which contains beta-xylose, alpha mannose and alpha galacturonic acid, and 3-O-methyl-alpha galactose, xylogalactoglucans, etc.

In 2015, a polysaccharide was described which was designated IP3a, is composed of rhamnose, arabinose, glucose and galactose.

Polysaccharides have many effects, especially beta glucans, which is widely known and recommended for compromised immunity.

Steroid compounds

Chaga also contains steroid compounds, which are substances containing a cholesterol core to which various side chains are attached. The most well-known sterol in Chaga is ergosterol, i.e. provitamin D2, although its concentration is not the highest. Lanosterol accounts for the largest proportion of mycosterols, i.e. 45% of all sterols, and inotodiol has 25%. Other steroid substances, including ergosterol, account for the remaining 30 %, which also includes phaekosterol, episterol, β-sitosterol, etc.

Terpenes, terpene compounds

Terpenes and their compounds are an integral part of vital fungi. A large number of different terpenoids have been obtained from Chaga fruiting bodies and mycelia.

Among the important ones are the lanostane triterpenoids - inolactones A, B and C, the triterpenoids phosphocarianol D, p-hydroxybenzoic acid, ferulic acid, trametenolic acid, etc.

Phenols and phenolic compounds

The composition of Chaga is still being discovered. This is mainly due to the fact that new extraction methods are being developed which will make it possible to find other compounds which have so far remained hidden. Phenols in general are known for their antioxidant effects. In Chaga there are e.g. resorcinol, syringol, ceresol, mequinol, guaiacol. Inonoblins A, B, C and phelligridins D, E and G are also important. There are also caffeic, gallic, syringic and protocatechuic acids, 3,4-dihydroxybenzalacetone.

Betulinic acid, betulin

Betulinic acid (a pentacyclic acid) and betulin (a pentacyclic triterpenic alcohol) are present in Chaga due to its host, which is birch. Chaga literally sucks them in from the birch tree. Normally there may be a problem with the absorption of these two terpenes, if ingested, from the digestive system, but if taken in Chaga, they are well absorbed into the body.

Both of these compounds make up 2% of the mushroom and have significant biological effects. The properties of betulin and betulinic acid are being studied in cancer, inflammation models and also in models of various viral infections. The results are indeed interesting and positive.

Melanin

Chaga, the part of the tree that protrudes above the bark, is black. It is logical that it must contain a pigment that allows this dark colouration. This is similar to melanin in our bodies, which is produced by the conversion of the amino acid tyrosine. Melanin is known to have a protective effect on our health and a lack of it increases the risk of, for example, skin cancer. Melanin is therefore a powerful antioxidant and protector against UVB, thus it can be said to have anti-cancer and anti-mutagenic effects.

Amino acid and protein

Chaga also contains substances that are essential for us, namely amino acids and proteins. These are also amino acids that our body cannot produce on its own and is therefore dependent on the food supply. 14 amino acids have been found in Chaga, and even 16 in the mycelium of Chaga. The highest concentrations are glycine, cysteine and tryptophan. Of the complex proteins, the enzymes are undoubtedly the most interesting. Since Chaga is a parasite and draws its nutrients from the woody part of the plant, it must be able to break down the wood. It therefore contains, for example, chitinase and other enzymes that break down cellulose, hemicellulose, etc. Interestingly, superoxide dismutase, which is also found in the human body, can also be found in Chaga. It is an enzyme that acts antioxidant, i.e. it reduces oxidative stress and "breaks down" free radicals. The activity of the enzyme in the body decreases with increasing age. By reducing oxidative stress, it also reduces tissue degeneration and inflammatory processes in the body.

Fatty acids and fats

There are not many plants that contain fatty acids and fats. These are most often only found in seeds. This is not the case with mushrooms. Chaga contains both saturated fatty acids and those that are very beneficial to health, i.e. unsaturated fatty acids. These are mainly oleic and linoleic acid. Like other representatives of the plant kingdom, it does not contain cholesterol.

Vitamins, mineral and trace elements

If we focus on the composition of Chaga, we can not forget about the vitamins and minerals contained in it. They are far from covering the daily requirement. These are mainly sodium, calcium, magnesium, iron, copper, manganese, zinc, germanium, etc. Vitamins in Chaga are mainly represented by those of the B group and the already mentioned vitamin D, beta carotene is also present.

Below, for example, is also a table describing some of the ingredients of Chaga, as can be seen, there are many of them, and even there not all are described.

Mazurkiewicz W, Rydel K, Pogocki D, Lemieszek MK, Langner E, Rzeski W. Separation of an aqueous extract Inonotus obliquus (Chaga). A novel look at the efficiency of its influence on proliferation of A549 human lung carcinoma cells. Acta Pol Pharm. 2010 Jul-Aug;67(4):397-406.