CHAGA: CHARACTERISTICS, REPRODUCTION, PROPERTIES, CONTRAINDICATIONS - BIOLOGY - 2025

The chaga (Inonotus obliquus) is a Basidiomycota fungus of the Hymenochaetaceae family, a birch phytopathogen that is characterized among other aspects by presenting a monomytic hyphal system and having a very infrequent sexual reproduction, which only occurs two or three years after the death of the host plant.

It is a widely distributed species in the northern hemisphere, causing the disease known as birch chaga, although it can occasionally attack other species of deciduous trees. This disease is of the type of white rots that mainly decompose lignin and cellulose to a lesser degree.

Inonotus obliquus, infesting a birch. Taken and edited from: Tomas Čekanavičius.

The fungus has medicinal properties that have been used by man since ancient times. Among the ailments that can be relieved or cured by Inonotus obliquus are gastric and duodenal ulcers, gastritis, tuberculosis, rheumatism, various liver and heart diseases, as well as different types of cancer.

However, there are no or very few medical studies carried out to verify the medicinal properties of chaga. In some cases its intake can have harmful side effects, for example in people with autoimmune diseases or taking drugs for diabetes or for blood circulation.

characteristics

Reproduction and life cycle

Basidiospores that reach wounds in a tree (broken branches, for example), germinate inside these and will spread through the heartwood for several years and even for several decades, decomposing the lignin and to a lesser extent the cellulose, causing rottenness. white.

After approximately four years of infection, the mycelium of the fungus fractures the bark of the host and produces hard outgrowths with a cracked surface and black coloration that can reach up to 1.5 m long and 15 cm thick and can reach weigh up to 5 kg.

These structures can produce asexual spores (chlamydospores) that aid in the spread of the disease. Up to 3 outgrowths or chagas can appear in the same place.

Macro view of Inonotus obliquus. Taken and edited from: This image was created by user Jimmie Veitch (jimmiev) at Mushroom Observer, a source for mycological images.You can contact this user here.English - español - français - italiano - македонски - português - +/−.

The fungus continues to invade the host's tissues and weaken it to death. The sexual reproduction of the fungus will begin only when the tree is dying or totally dead, the fruiting bodies begin to occur under the bark and are initially a whitish mycelial mass.

As the fruiting bodies develop, they exert pressure on the crust, which ends up breaking and the basidiocarps come into contact with the outside, it is at that moment when they initiate the formation of basidiospores.

The fruiting bodies emerge in summer and are inverted or resupinous, hard and brittle when dry, and can be easily detached from the host. The basidia of the hymenium are tetrasporic and ephemeral as they are quickly consumed by insects that help in the dispersal of the basidiospores.

Composition

Chaga is composed mainly of carbohydrates, making up more than 70% of its dry weight. In turn, among carbohydrates, the main component is lignin (32.6%). Its protein content is low 2.4%, but it also contains important substances such as glycine, aspartic acid, glutamic acid and nine other vitamins.

It contains lanosterol, einotodiol, ergosterol, fungisterol, tramethenolic acid and other terpenes, the amounts of which depend on environmental conditions and the location where the fungus develops.

Other bioactives of pharmacological interest that have been isolated from chaga include agaricic, syringic and vanillic acids, as well as betulin, a compound easily transformable into betulinic acid which has greater bioactivity.

Culture

Inonotus obliquus culture is carried out mainly as an in vitro mycelial culture to obtain bioactives produced by the fungus, such as betulin for example. In these crops, different substances are generally tested that optimize the production of such bioactives.

For example, the addition of MgSO ₄ to the culture medium enhances the production of betulin, while glucose, peptone and calcium chloride significantly affect the production of triterpenoids by Inonotus obliquus.

Properties

Chaga is an adaptogen, that is, an element that supplies the body with various nutrients that help it adapt to stressful conditions. Among the effects of the intake of Inonotus obliquus or extracts of the fungus are:

Antitumor effect

The polysaccharides present in fungi have biological activity that inhibits tumor growth, as well as having immunomodulatory capacity. Chaga is used in traditional medicine to prevent cancer and its effect is greater if it is consumed in the early stages of development of tumor diseases.

The mushroom is frequently used in traditional medicine in Russia, Poland and Belarus, and studies have shown that in regions where its use is widespread, the incidence of cancer is lower than in other areas where it is not consumed. Even in Russia its use is scientifically recognized for the treatment of gastric and lung cancer.

Triterpenes, endopolysaccharides and sterols synthesized by Inonotus obliquus have been shown to have antimicrobial effects, cell growth modulators, especially B lymphocytes and macrophages, apoptosis inducers or antitumors among others, not only in in vitro studies, but also in vivo.

Antioxidant effect

The polyphenols, polysaccharides and steroids present in chaga have antioxidant capacity. Researchers have demonstrated such effects in in vitro cell cultures of mice and humans, as well as in vivo in laboratory mice. The melanin that chaga also has, protects the skin against the effects of ultraviolet rays.

Lowers blood sugar and cholesterol

Trials with mice have shown the ability of Inonotus obliquus to lower blood sugar levels. It also reduces insulin resistance. These studies have shown that chaga can lower blood sugar levels by more than 30%, helping to prevent or control diabetes.

Researchers have found similar results in studies on the effects of the fungus on the concentration of cholesterol in the blood of mice. Inonotus obliquus extracts given to mice decreased the concentration of "bad" cholesterol and triglycerides.

Scientists, however, have not yet proven these effects in humans.

Other effects

Inonotus obliquus extracts have shown other effects, among them, analgesic, anti-inflammatory, antihypertensive, inhibitory activity on the proteases of the HIV-1 virus, protective against human flu A and B, among others.

In particular, betulin and betulinic acid synthesized by Inonotus obliquus exhibit antitumor, antiviral, antibacterial, anti-inflammatory and antimalarial activity.

Different phases of the development of the chaga (Inonotus obliquus). Taken and edited from: Henk Monster.

Contraindications

Scientists have not yet shown the possible effects that could exist on the fetus and the infant. Because of this, it is not recommended that pregnant or breastfeeding women use products derived from Inonotus obliquus or directly consume the fungus.

Chaga could interact with medications to control blood glucose or with insulin, which is why its application is not recommended in these cases. The blood-thinning effect of chaga may interact with similar medications. Likewise, the enhancing effect of the immune system could harm people with autoimmune diseases.

References

1. JR Sharma, K. Das & D. Mishra (2013). The genus Inonotus and its related species in India. Mycosphere.
2. Inonotus obliquus. On Wikipedia. Recovered from: en.wikipedia.org.
3. M. Kuo. Inonotus obliquus. Recovered from: mushroomexpert.com.
4. C. Illana-Esteban (2011). Medicinal interest of "chaga" (Inonotus obliquus). Bulletin of the Mycological Society of Madrid.
5. Y.-H. Bai, Y.-Q. Feng, D.-B. Mao, C.-P. Xu (2012). Optimization for betulin production from mycelial culture of Inonotus obliquus by orthogonal design and evaluation of its antioxidant activity. Journal of the Taiwan Institute of Chemical Engineers.
6. The Sex life of The Chaga Mushroom. Recovered from: annandachaga.com.