Know in one minute about Honey mushrooms Honey mushrooms or Armillaria mellea is a mushroom that commonly grows on trees and woody shrubs. It is the world’s largest living fungi. It is a facultative saprophytic fungus that feeds on dead or decaying parts of plants. Only cooked Honey mushrooms are edible, raw mushrooms cause mushroom poisoning. Consumption of honey mushrooms with alcohol causes nausea, vomiting and other health issues. These mushrooms damage the forest plant by causing them white rot root disease, therefore, they are known as forest pathogens.

Note: This article on Honey mushrooms is for informational purposes only. We do not recommend eating this mushroom without conducting thorough research and consulting a qualified expert.

Introduction

Honey mushrooms or Armillaria mellea grow on living or dead trees in tufts and on woody shrubs, only in autumn. It is the largest living fungi in the world. These mushrooms cause damage to forests. They are traditionally used as medicine in some countries.

Armillaria feeds on dead and decaying plant parts, therefore it is a facultative saprophyte mushroom. It is responsible for white rot root disease in forest plants; hence it is considered a destructive forest pathogen. 

The reproductive structure of mushrooms is basidiocarp, grown in clumps on wood. Coniferous, various monocot and dicot trees, shrubs, herbs, and large trees are common hosts of honey mushrooms. 

Common name

Armillaria mellea is commonly known as honey mushroom and Zhen–mo ( in China)

Synonyms

Agaricus melleus vahl (1790)

Agaricus sulphureus Weinm.

Armillaria mellea var. glabra Gillet (1874)

Armillaria mellea var. sulphurea (Weinm.) Fr. ( 1879)

 Armillaria mellea  (Vahl) P. Karst. (1881)

Armillaria mellea var. maxima Barla ( 1887)

Armillaria mellea var. minor Barla ( 1887)

Clitocybe mellea (Vahl) Ricke (1915)

Lepiota mellea (Vahl) J.E. Lange (1915)

Classification

Kingdom	Fungi
Division	Basidiomycota
Class	Agaricomycetes
Order	Agaricales
Family	Physalacriaceae
Genus	Armillaria

Appearance

Caps

Caps are yellow–brown in colour and conical to convex in shape with depression in the centre. When moist it is slightly sticky.

Gills

Gills are pale in colour.

Stem

Stems are smooth or scaled and pink, dark brown or pale in colour with or without a ring.

Spores

Spores are produced in between gills. Pale in colour.

Spore print

Spore prints are white

Taste

Slightly sweet taste

Note – Armillaria mellea looks similar to Pholiota spp. That also grows on the wood and fruits in clusters. Pholiota spp. Are yellow to greenish yellow in colour with grey–brown spore prints. So do not confuse Armillaria mellea with Pholiota spp.

Bioactive compound present

The bioactive compounds present in the extract are given in the list below:

malic acid	5.64 g /100 g of dry weight (dw)
citric acid	0.57 g /100 g of dw
fumaric acid	0.52  g /100 g of dw
oxalic acid	0.03 g /100 g of dw
cinnamic acid	72.89 μg  /100 g of dw
δ- tocopherol	42.41 μg  /100 g of dw
p- hydroxybenzoic acid	36.71 μg  /100 g of dw
linoleic acid	63.80 %
oleic acid	15.47 %
palmitic acid	12.63%

Nutritional value

Honey mushrooms or Armillaria mellea are rich in nutritional components. The nutritional value per 100 grams of dry weight is given below (1 & 2).

Carbohydrate	81.25 g
Fat	1.97 g
Protein	1.81 g
Mannitol	5.92 g
Trehalose	1.72 g

 Fruiting bodies contain low-fat values, 70 % of fatty acid is unsaturated fatty acids (2).

Benefits of Honey mushroom

1. Antioxidant activity

Honey mushroom is rich in natural antioxidant compounds. The extract of this mushroom shows great antioxidant activity through its reducing power, free radical scavenging activity and lipid peroxidation inhibition.

Hence, can be used as an antioxidant agent in the food industry (1 & 2). The organic acid such as maleic acid, citric acid, fumaric acid and oxalic acid present in the extract of Armillaria mellea is involved in oxidative stress reduction (1).

2. Antimicrobial activity

The extract of Armillaria mellea contains bioactive compounds that show its antimicrobial activity against Candida albicans, S. aureus and P. aeruginosa. The bioactive compounds inhibit the growth of these microbes (1).

3. Antibiofilm formation activity

The methanolic extract of Armillaria mellea inhibits the formation of biofilm of P. aeruginosa more effectively than antibiotics such as streptomycin and ampicillin.

Biofilm formation is a process whereby microorganisms irreversibly attach to and grow on a surface and produce extracellular polymers that facilitate attachment and matrix formation, resulting in an alteration in the phenotype of the organisms with respect to growth rate and gene transcription (3).

P. aeruginosa produces pyocyanin which is a virulence factor which shows antimicrobial resistance, the methanolic extract of Armillaria mellea effectively inhibits the production of pyocyanin in the 0.5 MIC (1).

4. Cytotoxicity

The ethanolic extract of Armillaria mellea contains armillarikin and armillaridin compounds, and shows cytotoxicity potential against tested human tumour cell lines (Huh 7, HepG2 and HA22T cell lines) (1).

Medicinal benefits

• Honey mushrooms is a medicinal mushroom which is traditionally used as herbal medicinal in China.
• Mainly used for the treatment of hypertension, epilepsy, headache, neurasthenia, and insomnia.
• Polyunsaturated fatty acids are found in abundance in honey mushrooms, which shows many health benefits (1).
• The extract of this mushroom contains various bioactive compounds.
• Which shows antioxidant activity, and antimicrobial activity toward pathogens (1).

 Side effects

1. If raw honey mushrooms are consumed it results in mushroom poisoning.
2. Eating mushrooms before or after the consumption of alcohol causes nausea and vomiting. 
3. In some cases, it can cause allergic reactions.

Edibility

• Honey mushrooms are one of the best edible wild mushrooms in countries like Germany, Poland, Russia, and other European countries.
• But it must be cooked well for eating because raw mushrooms cause poisoning.
• Avoid the consumption of honey mushrooms with alcohol consumption.
• If you want to eat honey mushrooms, avoid alcohol 24 hours before and 24 hours after eating this mushroom.

Q&A

1. How to cook honey mushrooms?

Honey mushrooms can simply be cooked in a  pan with some oil, ginger and garlic. Add soy sauce, mix it well, garnish it with fresh coriander leaves and serve it.

2. How to identify honey mushrooms?

Honey mushrooms can be identified from the following features

• Honey mushrooms have pale yellow long stems with dark brown or white rings.
• Honey mushrooms grow in tufts/ clusters from a single point.
• These mushrooms have a white spore print.

3. What is special about honey mushrooms?

Honey mushrooms contain several bioactive compounds which are beneficial for health and support immune systems to work properly. It contains polysaccharides that effectively work as antioxidants against the free radicals that damage the cells. It also contains amino acids such as citric acid, fumaric acid, maleic acid and oxalic acid that play an important role in reducing oxidative stress.

Written By: Neetu Ladiya