Honey Mushroom – Armillaria mellea

Japanese name – Naratake
Chinese name – Mi Huan Jun

A. mellea is a common fungus that produces edible fruiting bodies with a distinctive golden colour. A single example can grow to cover a vast area and it is reported that the largest living organism in the world is a related species of honey fungus covering an area of 2400 acres in Oregon, USA, with estimates of its age ranging from 1900 to 8650 years1.
Although responsible for the death of many trees and garden shrubs, A. mellea is essential for the growth of other plants, including the important Chinese herb Gastrodia elata (Tian Ma), which is used to treat conditions including vertigo, dizziness, headache, stroke and convulsions and whose medical properties A. mellea mirrors. Indeed A. mellea is considered the more potent of the two with an effective dosage half that of Tian Ma2,3.
Early reports indicated that A. mellea and G. elata shared the same active components but it is now known that they differ in their active metabolites. As well as being essential for the growth of G. elata, it has been shown that Armillaria species are involved in sclerotium formation in Polyporus umbellatus (see P. umbellatus section).
A. mellea mycelium contains high levels of polysaccharides with anti-ageing, immunomodulating and anti-vertigo activity4,5. In addition, nucleoside analogues play a role in some of A. mellea’s functions and a number of indole compounds have been isolated including tryptamine, L- tryptophan and serotonin, with A. mellea fruiting bodies containing 2.207mg serotonin per 100g dry weight6,7.
Several antibiotics, primarily sesquiterpene aryl esters, have been isolated from A. mellea and show strong action against gram-positive bacteria (Staphylococcus, Streptococcus, Enterococcus etc.), as well as yeasts and other fungi8-10.

NEUROLOGICAL
– Tablets composed of A. mellea mycelium are prescribed in China for treating a variety of neurological conditions including Meniere’s Syndrome, vertigo, headache, insomnia, epilepsy, neurasthenia and hypertension2,3,11-14.
A. mellea fermentation extract showed anti-convulsant properties, raising the seizure threshold in PTZ-induced seizures in mice15, while an adenosine derivative from the mycelium abolished neurogenic twitch responses induced by electrical field stimulation with both pre- and post-synapse depression, as well as being found to be 1,000 times stronger than adenosine in its cerebral protecting activity5. In addition A. mellea polysaccharide extract was shown to benefit vertigo induced by machinery rotation16.

CLINICAL SUMMARY
Main Therapeutic Application – Meniere’s syndrome, vertigo, epilepsy.
Key Components – Polysaccharides, nucleoside derivatives and sesquiterpene aryl esters.
Dose – Mycelial tablets are used in China 3-4g/day.


REFERENCES

1. Coarse-scale population structure of pathogenic Armillaria species in a mixed-conifer forest in the Blue Mountains of northeast Oregon. Ferguson BA, Dreisbach TA, Parks CG, Filip GM, Schmitt CL. Can J For Res, 2003;33(4):612–623.
2. Modernizing chinese medicine – the case of Armillaria as Gastrodia substitute. Dharmananda S. www.itmonline.org/arts/gastrodia.htm.
3. Tian ma, an ancient Chinese herb, offers new options for the treatment of epilepsy and other conditions. Ojemann LM, Nelson WL, Shin DS, Rowe AO, Buchanan RA. Epilepsy Behav. 2006;8(2):376–383.
4. The cultivation, bioactive components and pharmacological effects of Armillaria mellea. Gao LW, Li WY, Zhao YL, Wang JW. Afr J Biotech. 2009;8(25):7383–7390.
5. A polysaccharide from Armillaria mellea exhibits strong in vitro anticancer activity via apoptosis-involved mechanisms. Wu J, Zhou J, Lang Y, Yao L, Xu H, Shi H, Xu S. Int J Biol Macromol. 2012;51(4):663–667.
6. A novel N6-substituted adenosine isolated from mi huan jun (Armillaria mellea) as a cerebral-protecting compound. Watanabe N, Obuchi T, Tamai M, Araki H, Omura S, Yang JS, Yu DQ, Liang XT, Huan JH. Planta Med. 1990;56(1):48–52.
7. Analysis of indole compounds in Armillaria mellea fruiting bodies. Muszyńska B, Maślanka A, Ekiert H, Sułkowska-Ziaja K. Acta Pol Pharm. 2011;68(1):93–97.
8. Armillaric acid, a new antibiotic produced by Armillaria mellea. Obuchi T, Kondoh H, Watanabe N, Tamai M, Omura S, Yang JS, Liang XT. Planta Med. 1990;56(2):198–201.
9. Antimicrobial and antioxidant activities of mycelia of 10 wild mushroom species. Kalyoncu F, Oskay M, Sağlam H, Erdoğan TF, Tamer AU. J Med Food. 2010;13(2):415–419.
10. Antibacterial sesquiterpene aryl esters from Armillaria mellea. Donnelly DM, Abe F, Coveney D, Fukuda N, O’Reilly J, Polonsky J, Prangé T. J Nat Prod. 1985;48(1):10–16.
11. To use Armillaria fungus tablet to replace Gastrodia tuber in treating 45 cases with syndrome of deficiency of yin and flourishing yang. The TCM Department of Capital Hospital and Fuwai Hospital, Beijing. Chin J  Med. 1977;(8):473–474.
12. Observation on curative effects of Armillaria mellea fungus tablet in treating 100 cases of neurasthenia and hypertension, etc. Zhou Linshen. J New Med. 1978;(10):13.
13. Curative effects of Gastrodia tuber Armellaria fungus tablet in treating some diseases of the nervous system. Jiangsu Journal of TCM. 1980;(1):35–37.
14. Antioxidant and antiedema properties of solid-state cultured honey mushroom, Armillaria mellea (higher Basidiomycetes), extracts and their polysaccharide and polyphenol contents. Lai MN, Ng LT. Int J Med Mushrooms. 2013;15(1):1–8.
15. Pharmacological actions of Gastrodia watery preparation and fermentation liquid of Armellaria mellea on nervous system. Chin J Med. 1977;(8):470–472.
16. Study on the anti-vertigo function of polysaccharides of Gastrodia elata and polysaccharides of Armillaria mellea. Yu L, Shen YS, Miao HC. Chin J Information TCM. 2006;13(8):29–36.