Inonotus obliquus

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Inonotus obliquus
Scientific classification
Kingdom:Fungi
Division:Basidiomycota
Class:Agaricomycetes
Order:Hymenochaetales
Family:Hymenochaetaceae
Genus:Inonotus
Species:I. obliquus
Binomial name
Inonotus obliquus
(Ach. ex Pers.) Pilát (1942)
Synonyms[1]

Boletus obliquus Ach. ex Pers. (1801)
Polyporus obliquus (Ach. ex Pers.) Fr. (1821)
Physisporus obliquus (Ach. ex Pers.) Chevall. (1826)
Poria obliqua (Ach. ex Pers.) P.Karst. (1881)
Fomes obliquus (Ach. ex Pers.) Cooke (1885)
Phaeoporus obliquus (Ach. ex Pers.) J.Schröt. (1888)
Mucronoporus obliqua (Ach. ex Pers.) Ellis & Everh. (1889)
Scindalma obliquum (Ach. ex Pers.) Kuntze (1898)
Phellinus obliquus (Ach. ex Pers.) Pat. (1900)
Xanthochrous obliquus (Ach. ex Pers.) Bourdot & Galzin (1928)
Fuscoporia obliqua (Ach. ex Pers.) Aoshima (1951)

 
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Inonotus obliquus
Scientific classification
Kingdom:Fungi
Division:Basidiomycota
Class:Agaricomycetes
Order:Hymenochaetales
Family:Hymenochaetaceae
Genus:Inonotus
Species:I. obliquus
Binomial name
Inonotus obliquus
(Ach. ex Pers.) Pilát (1942)
Synonyms[1]

Boletus obliquus Ach. ex Pers. (1801)
Polyporus obliquus (Ach. ex Pers.) Fr. (1821)
Physisporus obliquus (Ach. ex Pers.) Chevall. (1826)
Poria obliqua (Ach. ex Pers.) P.Karst. (1881)
Fomes obliquus (Ach. ex Pers.) Cooke (1885)
Phaeoporus obliquus (Ach. ex Pers.) J.Schröt. (1888)
Mucronoporus obliqua (Ach. ex Pers.) Ellis & Everh. (1889)
Scindalma obliquum (Ach. ex Pers.) Kuntze (1898)
Phellinus obliquus (Ach. ex Pers.) Pat. (1900)
Xanthochrous obliquus (Ach. ex Pers.) Bourdot & Galzin (1928)
Fuscoporia obliqua (Ach. ex Pers.) Aoshima (1951)

Inonotus obliquus, commonly known as chaga mushroom (a Latinisation of the Russian term 'чага'), is a fungus in Hymenochaetaceae family. It is parasitic on birch and other trees. The sterile conk is irregularly formed and has the appearance of burnt charcoal. It is not the fruiting body of the fungus, but a mass of mycelium, mostly black due to the presence of massive amounts of melanin. The fertile fruiting body can be found very rarely as a resupinate (crustose) fungus on or near the clinker, usually appearing after the host tree is dead. I. obliquus grows in birch forests of Russia, Korea, Eastern and Northern Europe, northern areas of the United States, in the North Carolina mountains and in Canada.

The chaga mushroom is considered a medicinal mushroom in Russian and Eastern European folk medicine and research on its medicinal potential is ongoing. However there is currently no evidence for its effectiveness or safety for medicinal use.

Name[edit]

The name chaga (pronounced "tsjaa-ga") comes from the Russian word of the mushroom (anglicized from czaga), which in turn is purportedly derived from the word for the fungus in Komi-Permyak, the language of the indigenous peoples in the Kama River Basin, west of the Ural Mountains. It is also known as the clinker polypore, cinder conk, black mass and birch canker polypore.[2]

In Norwegian, the name is kreftkjuke' which literally translates as "cancer polypore", referring to the fungus' appearance or to its alleged medicinal properties. In Finnish, the name is pakurikääpä, combined from pahkura and kääpä translating as "wart polypore".

In England and Canada, it is known as the sterile conk trunk rot of birch, which refers to the fruiting bodies growing under the outer layers of wood surrounding the sterile conk once the tree is dead, to spread the spores. In France, it is called the carie blanche spongieuse de bouleau (spongy white birch tree rot), and in Germany it is known as Schiefer Schillerporling (slate Inonotus). The Dutch name is berkenweerschijnzwam (birch glow mushroom).

Within the wilderness survival community, it is called tinder fungus[3] (this name is also claimed for fomes fomentarius), because it can catch a weak spark and form a coal that can be used to kindle a fire.

Medicinal use[edit]

Chaga has been used as a folk remedy in Russia and Siberia since the 16th century.[4] According to the Memorial Sloan–Kettering Cancer Center, "no clinical trials have been conducted to assess chaga's safety and efficacy for disease prevention or for the treatment of cancer, cardiovascular disease, or diabetes". They caution that the mushroom extract can interact with other drugs.[5]

Laboratory studies on extract of chaga mushroom has indicated possible future potential in cancer therapy,[6] as an antioxidant,[7] in immunotherapy,[8] and as an anti-inflammatory.[9]

Chemical analysis shows that chaga mushroom contains a range of secondary metabolites, including phenolic compounds such as melanins, and lanostane-type triterpenes, which include a small percentage of betulinic acid.[citation needed]

Chemical isolates[edit]

Inotodiol, melanin, trametenolic acid, and the betulinic acid precursor, betulin, are researched Inonotus obliquus isolates.

Cultivation[edit]

Geographically this fungus is mostly found in very cold habitats. It grows very slowly, suggesting it is not a reliable source of bioactive compounds in the long run. Attempts at cultivating this fungus all resulted in a reduced and markedly different production of bioactive metabolites.[10][11] Secondary metabolites were either absent or present in very different ratios, and in general showed significantly less potency in cultivated Chaga.[12] Cultivated Chaga furthermore results in a reduced diversity of phytosterols, particularly lanosterol, an intermediate in the synthesis of ergosterol and lanostane-type triterpenes. This effect was partially reversed by the addition of silver ion, an inhibitor of ergosterol biosynthesis.[10]

Additionally, the bioactive triterpene betulinic acid is completely absent in cultivated Chaga. In nature Chaga grows pre-dominantly on birches, and birch bark contains up to 22% of betulin. Betulin is poorly absorbed by humans, even when taken intravenously; its bioavailability is very limited. However, the Chaga mushroom converts betulin into betulinic acid, and many internet sources state Chaga's betulinic acid is bioavailable, even when taken orally. Unfortunately there is no research that confirms this claim.[13]

Chaga dietary supplements[edit]

In China, Japan and South Korea, extracts of chaga and other mushrooms from the family Hymenochaetaceae are being produced, sold and exported as anticancer medicinal supplements. The main bioactive ingredient in these extracts are usually (1>3)(1>6) Beta-D-glucans, a type of water-soluble polysaccharide. The biologic properties of crude preparations of these specific β-D-glucans have been subject of research since the 1960s.[citation needed]

Russian literature Nobel Prize laureate Alexandr Solzhenitsyn wrote two pages on the medicinal use and value of chaga in his autobiographical novel, based on his experiences in a hospital in Tashkent, Cancer Ward (1968).[citation needed]

Preparation[edit]

Chaga on a birch tree

Chaga is traditionally grated into a fine powder and used to brew a beverage resembling coffee or tea. For medicinal use, an extraction process is needed to make at least some of the bio-active components bioavailable.[14] These bio-actives are found in the mostly indigestible chitin cell walls of the chaga. Humans lack the enzyme chitinase, so cannot fully digest raw mushrooms or their derivatives, and the digestive process works too fast for the stomach acid to take effect. Scientific studies and research are in general also based on highly concentrated extracts, and traditional Russian usage is also based on a form of hot-water extraction (by preparing zavarka).

Currently, three extraction processes are used, each with a different outcome.

Extracts with a therapeutic value usually combine two methods, usually hot water and ethanol extraction. This will result in all bioactive components being present. Cheap, mass-produced extracts are in general hot water, low percentage (4-20%) polysaccharide extracts with limited therapeutic value. The information on the supplements' label will usually reveal inclusion or exclusion of components. However, the majority of mushroom dietary supplements that are sold are non-extracted, being the cheapest option.[14] To achieve at least some therapeutic effects the consumer has to make a tea from it.

See also[edit]

References[edit]

  1. ^ "Inonotus obliquus (Ach. ex Pers.) Pilát 1942". MycoBank. International Mycological Association. Retrieved 2011-10-11. 
  2. ^ Needham, Arthur (2005-12-16). "Clinker Polypore, Chaga". Retrieved 10 October 2011. 
  3. ^ Muma, Walter. "True Tinder Fungus". Retrieved 5 December 2012. 
  4. ^ Youn, Myung-Ja; Kim, JK; Park, SY; Kim, Y; Kim, SJ; Lee, JS; Chai, KY; Kim, HJ; Cui, MX; So, HS; Kim, KY; Park, R (2008). "Chaga mushroom (Inonotus obliquus ) induces G0/G1 arrest and apoptosis in human hepatoma HepG2 cells". World Journal of Gastroenterology 14 (4): 511–7. doi:10.3748/wjg.14.511. PMC 2681140. PMID 18203281. 
  5. ^ "Chaga Mushroom". Memorial Sloan–Kettering Cancer Center. 18 July 2011. Retrieved August 2013. 
  6. ^
    • Rzymowska, J (1998). "The effect of aqueous extracts from Inonotus obliquus on the mitotic index and enzyme activities". Bollettino chimico farmaceutico 137 (1): 13–5. PMID 9595828. 
    • Mizuno, Takashi; Zhuang, Cun; Abe, Kuniaki; Okamoto, Hidehumi; Kiho, Tadashi; Ukai, Shigeo; Leclerc, Sophie; Meijer, Laurent (1999). "Antitumor and Hypoglycemic Activities of Polysaccharides from the Sclerotia and Mycelia of Inonotus obliquus (Pers.: Fr.) Pil. (Aphyllophoromycetideae)". International Journal of Medicinal Mushrooms 1 (4): 301. doi:10.1615/IntJMedMushr.v1.i4.20. 
  7. ^ Cui, Y; Kim, DS; Park, KC (2005). "Antioxidant effect of Inonotus obliquus". Journal of Ethnopharmacology 96 (1–2): 79–85. doi:10.1016/j.jep.2004.08.037. PMID 15588653. 
  8. ^
    • Kim, Yong Ook; Han, Sang Bae; Lee, Hong Woen; Ahn, Hyo Jung; Yoon, Yeo Dae; Jung, Joon Ki; Kim, Hwan Mook; Shin, Chul Soo (2005). "Immuno-stimulating effect of the endo-polysaccharide produced by submerged culture of Inonotus obliquus". Life Sciences 77 (19): 2438–56. doi:10.1016/j.lfs.2005.02.023. PMID 15970296. 
    • Kim, Yong Ook; Park, Hae Woong; Kim, Jong Hoon; Lee, Jae Young; Moon, Seong Hoon; Shin, Chul Soo (2006). "Anti-cancer effect and structural characterization of endo-polysaccharide from cultivated mycelia of Inonotus obliquus". Life Sciences 79 (1): 72–80. doi:10.1016/j.lfs.2005.12.047. PMID 16458328. 
  9. ^
    • Park, Young-Mi; Won, Jong-Heon; Kim, Yang-Hee; Choi, Jong-Won; Park, Hee-Juhn; Lee, Kyung-Tae (2005). "In vivo and in vitro anti-inflammatory and anti-nociceptive effects of the methanol extract of Inonotus obliquus". Journal of Ethnopharmacology 101 (1–3): 120–8. doi:10.1016/j.jep.2005.04.003. PMID 15905055. 
    • Mishra, Siddhartha Kumar; Kang, Ju-Hee; Kim, Dong-Kyu; Oh, Seung Hyun; Kim, Mi Kyung (2012). "Orally administered aqueous extract of Inonotus obliquus ameliorates acute inflammation in dextran sulfate sodium (DSS)-induced colitis in mice". Journal of Ethnopharmacology 143 (2): 524–32. doi:10.1016/j.jep.2012.07.008. PMID 22819687. 
  10. ^ a b Zheng, W. F.; Liu, T.; Xiang, X. Y.; Gu, Q. (July 2007). "Sterol composition in field-grown and cultured mycelia of Inonotus obliquus". Yao xue xue bao = Acta pharmaceutica Sinica 42 (7): 750–756. PMID 17882960. 
  11. ^ Zheng W, Miao K, Liu Y, Zhao Y, Zhang M, Pan S et al. (2010). "Chemical diversity of biologically active metabolites in the sclerotia of Inonotus obliquus and submerged culture strategies for up-regulating their production". Appl Microbiol Biotechnol 87 (4): 1237–54. doi:10.1007/s00253-010-2682-4. PMID 20532760. 
  12. ^ Zheng, W. F. (July 2008). "Phenolic compounds from Inonotus obliquus and their immune-stimulating effects". Mycosystema 27 (4): 574–581. 
  13. ^ Müllauer, Franziska (2011). Betulinic Acid Induced Tumor Killing. 
  14. ^ a b Paper with background on extraction processes
  15. ^ Rhee, S.Y. (2008). "A comparative study of analytical methods for alkali-soluble β-glucan in medicinal mushroom, Chaga (Inonotus obliquus)". LWT - Food Science and Technology 41 (3): 545–549. doi:10.1016/j.lwt.2007.03.028. 

Further reading[edit]