Originally published in Plant Healer Quarterly

“Big fleas have little fleas upon their backs to bite ‘em.  

And little fleas have lesser fleas, and so, ad infinitum.  

And the great fleas, themselves, have greater fleas to go on, 

While these again have greater still, and greater still, and so on…”  

– Jonathan Swift 

Many of us think of ourselves and other beings as an “individuals”…Jane, Joe, Rex the dog, Tiger the cat.  In reality, life is more similar to a fractal, or perhaps a set of Russian nesting dolls.  We’re each a hodge podge of many smaller individuals; a collection of our cells as well as fungi and bacteria that do more than just tag along…they influence how we are. Don’t even get me started on the the viruses that infect our resident bacteria and fungi and influence how they are.  Even “our own” cells contain viral genetic sequences integral to our DNA. So microbial tag alongs may even influence who we are.  Not to forget the other end of the spectrum, in which we’re but one component of the larger organism of the planet.  “Individuals”, indeed. 

Plants are no exception to this nesting doll reality. When we make plant extracts, we are in fact making plant, fungal and bacterial extracts. Medicinals such as Chamomile, Mints, Saint John’s Wort, Skullcap, Rosemary, Geranium, Fennel, Artemesia and many others have been studied for their fungal and bacterial tag-alongs, called “endophytes” (1, 2), meaning “inside plants”.  In fact, all plant species tested to date contain endophytes, critters who hang around inside living tissue without causing disease. Wash the plant all you want before extracting and you don’t get rid of them. Endophytes exist either inside of or squeezed in between the plant cells. And, really, you may not want to get rid of them.  

“So what?”, you may ask. Well, endophytes may be a key determinant of the quality of our plant medicine.  As more and more research is pointing to just how much our health and emotional state are impacted by the health of our microbiome, it’s becoming clear that the growth, stress resistance and chemical make up of plants is dependent upon their resident microbiome, the endophytes. And, well, endophytes are pretty cool.  Have you heard of hypericin?  An endophyte can make it.  Diosgenin? Ditto.  Artemisin?  Yup. Taxol? You get the idea…    More on “plant” medicine momentarily.  First, let’s get in to the how, what and why of endophytes. 

Endophytes, you say?

If a plant geek, you’ve heard of mycorrhizal microbes that grow associated with plant roots. These bugs facilitate water and nutrient uptake by the roots and mediate plant-to-plant communication as well. Those that actually penetrate into the roots are endophytes. But endophytes are also found inside of seeds, leaves, stems, flowers, fruit, buds and bark (3). 

Most endophytes identified so far are filamentous fungi though many are bacteria (4), and they’re tough little bastards to study.  Most of the research looking at endophytes are folks interested in “drugifying” the metabolites that they make.  To study them scientists have to surface sterilize a plant then grind it up to release the endophytes, which they’ll attempt to culture on various growth media. But not all endophytes are willing to cooperate with this arrangement and refuse to be cultured.  Just how many different endophytes are out there?  One study alone cultivated 181 bacterial endophytes from 13 medicinal herb species (1). This, of course, doesn’t include those that can’t be grown in culture and the study didn’t look for fungal endophytes. Thus, the answer to how many endophytes are out there is “a shitload”.  

So, what do plants get out of this intimate arrangement?  In some cases, the endophyte grants the plant increased resistance to parasites or to grazing insects and animals.  Or a better likelihood of surviving changing environmental conditions. Or more robust growth.  And the endophyte?  Many survive in the soil for a long time without a plant home. But, when inside the plant, the endophyte gets necessary nutrients or completing its life cycle (3).  Though this relationship is not all roses; sometimes the relationship is antagonistic (Married with Children?) or parasitic (The Hunger?) rather than mutualistic (3).

When and how did endophytes get there initially???  Who the hell knows…  Have they been tagging along since the beginning?  Or, did plants become colonized somewhere down the line?  Plants are thought to have first set foot (er, root) on land by about 700 million years ago.  Fossil evidence points to a plant-endophyte relationship being in place by about 400 million years ago (5). So it’s certainly not a new partnership. 

As to the how, it’s known that some endophytes are transmitted vertically, meaning that they’re passed from mama to baby plants via seed. These are thought to be “obligate” endophytes that can’t exist outside of the plant (3).  Other endophytes are transmitted horizontally, meaning that they’re spread from plant to plant by endophyte spores (6). These are thought to be “facultative” endophytes, capable of hanging out in some form elsewhere but living inside of the plant for a good chunk of their lifecycle (3). So maybe at some point way back when, a spore made it’s way into a plant. After all, fungi were already hanging around on land long before plants showed up. Or, given that some plants need their endophytes in order to grow to maturity from seed (4) or to survive in a stressful environment (7), maybe endophytes were there from the very beginning and were pivotal to successful plant evolution. 

Back to medicinal plants

The existence of endophytes has been known for over a hundred years (4), yet I can’t claim to have though about them and their contribution to the medicine sitting in jars on my shelf until recently.  Plants obviously provide great medicine. Herbal medicine works because many of the secondary metabolites that aid the plants also benefit us. What’s become clear is that endophytes also make secondary metabolites, many that we typically associate with plants.

Endophytes may be influencing our plant medicine in multiple ways.  Clearly there are more plant chemicals by sheer mass than endophyte chemicals in that jar of macerating Peppermint in the cabinet.  But it’s evident that endophytes have an impact on that medicine. For example, there may be chemicals in those jars that likely wouldn’t be there if not for endophytes (8). In some cases, this is because the endophytes are synthesizing stuff that the plant doesn’t make itself. Alternatively, the endophyte may be stimulating the plant to make something it wouldn’t without the endophyte’s influence; resveratrol in Doug Fir is an example (4, 8).  Endophytes may also influence levels of metabolites the plant already makes on its own.  Echinacea’s immune modulating alkamides are an example of this (9).

Sometimes both the plant and the endophyte produce the same metabolite(s). In this case, the plant and endophyte may be sharing genes via gene transfer from one organism to the other, or they may have co-evolved the ability to make a particular metabolite, as seems to be the case in some Artemesia species (2). 

It’s theoretically possible that endophytes may be responsible for the primary medicinal actions of a plant in some cases. Either by directly producing strong medicinal metabolites that you don’t need a whole lot of for effects, or by influencing the plant’s production of medicinal stuff.  Endophytes themselves make a veritable cornucopia (yes, I went there) of medicinal compounds. There’s a handy table included here that was compiled for you tabley types. It lists many of the categories of secondary metabolites that endophytes produce, along with some specific examples. Anyone familiar with plant chemistry will immediately recognize that endophytes make a whole pile of metabolites that we typically think of as plant medicine.  

As mentioned, the majority of the research being carried out on endophytes is towards the discovery of novel new drugs. The relevance of endophytes is perhaps different for us herbalists…more on this monetarily. It’s known that fungal endophytes produce a larger array of secondary metabolites than bacterial do.  And, endophytes in desert and tropical plants make a wider variety of compounds than endophytes in temperate climes (4).  In any case, it’s interesting for us medicine making herbalists to know that the origin of our plant medicine is more complex than it seems at first glance.  

At this point, there are more questions than answers. For example…

• How much is the quality of our herbal medicine determined by the influence of growth conditions on the plant itself versus on the plant’s endophytes?   It seems likely that the answer is that both are important.  Many of us consider role of growing location and conditions as key determinants of how good our plant medicine will be. Studies to date show that these factors also impact who is living inside our medicinal plants (10), which is likely influencing our medicine.  

• Along those lines, how much do endophytes contribute to how good your Mugwort medicine is compared to the Mugwort grown in your second cousin’s garden on the other side of the country? If hers is a stronger dream herb, would it work to expose your soil and plants to her ground up Mugwort?   Research shows that environmental conditions do influence the endophytes present (10), so I wonder how such a transfer experiment would work if you live in Sedona, Arizona and your second cousin lives in Presque Isle, Maine.  I bet some endophytes will “take”.  

• Is there a potential problem in trying endophyte transfers such as these?  A chance, for instance, of transmitting an unwanted infection by a disease-causing organism? One idea that is appealing in this age of environmental degradation and over-harvesting is the idea of an endophyte library being created to help propagate endangered medicinal plants (10).   This would also reduce the chance of transferring unwanted critters cross country.     

These meanderings may be a bit more technical than the level at which many of us work day to day, but they’re relevant to our medicine and are something to chew on until next time, when we delve deeper into the critter chemical factories within some of our best known and loved medicinal plants.

References & further reading

1. Goryluk-Salmonowicz, A, et al (2016) Endophytic detection in selected European herbal plants. Pol J Micro. 65(3):369-75. http://www.pjmonline.org/endophytic-detection-in-selected-european-herbal-plants/

2. Huang, WY, et al (2007) Methods for the study of endophytic microorganisms from traditional Chinese medicine plants. Econom Bot. 61(1): 14-30. https://www.jstor.org/stable/4257167?read-now=1&loggedin=true&seq=1#page_scan_tab_contents

3. Gouda, S, et al (2016) Endophytes: A treasure house of bioactive compounds of medicinal importance. Frontiers in Microbiology. 7:1583. https://www.frontiersin.org/articles/10.3389/fmicb.2016.01538/full  REVIEW

4. Owen, NL & N Hundley (2004) Endophytes — The chemical synthesizers inside plants. Science Progress. 87(2):79-99. https://www.jstor.org/stable/43423175?seq=1#page_scan_tab_contents   REVIEW

5. Krings, M, et al (2007) Fungal endophytes in a 400-million-yr-old land plant: infection pathways, spatial distribution, and host responses. New Phytol. 174(3):648-57. https://www.researchgate.net/publication/6380784_Krings_M_Taylor_TN_Hass_H_Kerp_H_Dotzler_N_Hermsen_EJ_Fungal_endophytes_in_a_400-million-yr-old_land_plant_infection_pathways_spatial_distribution_and_host_responses_New_Phytol_174_648-657

6. Kaul, S, et al (2012)  Endophytic fungi from medicinal plants: a treasure hunt for bioactive molecules.  Phytochem Rev. 11(4):487-505. https://www.academia.edu/17123332/Endophytic_fungi_from_medicinal_plants_a_treasure_hunt_for_bioactive_metabolites   REVIEW

7. Rodriguez, R & R Redman (2008)  More than 400 million years of evolution and some plants still can’t make it on their own: plant stress tolerance via fungal symbiosis.  J Exp Biol. 59(5):1109-14. https://academic.oup.com/jxb/article/59/5/1109/538568

8. Huang, L-H, et al (2018) Endophytic fungi specifically introduce novel metabolites into grape flesh cells in vitro. PLOS One. 13(5): e0196996.   https://doi.org/10.1371/journal.pone.0196996

9. Maggini, V, et al (2017) Plant-endophytes interaction influences the secondary metabolism in Echinacea purpurea (L.) Moench: an in vitro model. Sci Rep. 7: 16924. https://www.nature.com/articles/s41598-017-17110-w

10. Jia, M, et al (2016) A friendly relationship between endophytic fungi and medicinal plants: A systemic review. Front. Microbiol. 7:906. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4899461/   REVIEW

11. Yu, H, et al (2010) Recent developments and future prospects of antimicrobial metabolites produced by endophytes. Microbiol. Res. 165(6):437-449. https://www.sciencedirect.com/science/article/pii/S0944501309001128  REVIEW

12. Gunatilaka, AAL (2012) Natural products from plant-associated microorganisms: Distribution, structural diversity, bioactivity and implications of their occurrence. J Nat Prod. 69(3):509-26.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3362121/  REVIEW

13  Golinska, P, et al (2015) Endophytic actinobacteria of medicinal plants: diversity and bioactivity.    Antonie van Leeuwenhoek. 108:267–289.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4491368/  REVIEW

14. Venieraki, A, et al (2017) Endophytic fungi residing in medicinal plants have the ability to produce the same or similar pharmacologically active secondary metabolites as their hosts. Hellenic Plant Prot J. 10:51-66.  https://www.researchgate.net/publication/318656074_Endophytic_fungi_residing_in_medicinal_plants_have_the_ability_to_produce_the_same_or_similar_pharmacologically_active_secondary_metabolites_as_their_hosts REVIEW

15. Kual, S, et al (2013) Prospecting endophytic fungal assemblage of Digitalis lanata Ehrh. (foxglove) as a novel source of digoxin: a cardiac glycoside. 3 Biotech. 3(4): 335-40. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3723867/

16. Kuar, A, et al (2017) Secondary metabolites from fungal endophytes of Echinacea purpurea suppress cytokine secretion by macrophage-type cells. Nat Prod Commun. 11(8):1143-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5414731/

17. Nicoletti R & A Fiorentino (2015) Plant bioactive metabolites and drugs produced by endophytic fungi of spermatophyta. Agriculture. 5:918-970.  http://www.mdpi.com/2077-0472/5/4/918/htm

18. Zin Z, et al (2017) Antimicrobial activity of saponins produced by two novel endophytic fungi from Panax notoginseng. 31(22):2700-03.  https://www.tandfonline.com/doi/abs/10.1080/14786419.2017.1292265

19. Lu, H et al (2000) New bioactive metabolites produced by Colletotrichum sp., an endophytic fungus in Artemesia annua. Plant Sci. 151(1):67-73. http://www.paper.edu.cn/scholar/showpdf/NUz2MN2INTz0kxeQh

An interview for the wonderful Kelly Moody’s podcast.Check out her site for a whole bunch of great episodes on stuff plant related and more!

https://www.ofsedgeandsalt.com/podcastblog/annamarijahelt?fbclid=IwAR1ueuKkcMFyAg1oLymPj6PjQTgkVs9mcFDDozfmJ7dRZSUoS_hQ0SnwozY

Any of you who’ve stuck your nose up to a mushroom know that they are aromatic.  Even if they just smell like “mushroom”, which, by the way, is largely due to the chemical octanol and its relatives. Some mushrooms smell wonderful (fresh Oyster Mushrooms in the forest); others, not so much (Stinkhorn!).

Mushroom volatile chemicals have been less sussed out than those of plants.  “Volatile” simply means that a molecule evaporates readily at ambient temperature.  Anyway, there are over 100,000 described fungal species. Aromatics have been assessed in maybe 100 of these (1), and, not all of these are fungi of the “mushroom” persuasion. Most of the info on mushroom aroma comes from work done by ecologists studying interactions among species and by folks in the food or perfume industry.  

Mushroom volatiles fall into the chemical categories that you aromatherapists will recognize from plants. (Nature doesn’t often reinvent the wheel.) These include hydrocarbons, terpenes, ketones, acids, aldehydes, alcohols, esters, hetero-cycles, nitrogen-containing compounds thiols (sulfur-containing…stinky!) and aromatics (confusingly, referring to chemical structure rather than scent)(1). We’re inhaling these in while walking in the woods, and also when stuck inside a musty, old building.  

And, not all mushroom odors are actually made by the mushroom.  Some, instead, come from other fungi or even bacteria living on or in the shroom. Truffles are prized for their distinctive scent, but the bacteria that hitchhike along with Truffles should get a big part of the credit (1).  Others mushroom aromatics come from the substrate that the mushroom is “eating” (1).

Why do mushrooms have an aroma?

For the same reasons plants do:  Growth, development, reproduction, competition and protection. Some mushroom aromatics may regulate if and when a mushroom sporulates. Others may protect the fruiting body from being eaten, or may lure in “pollinators” to spread the mushroom spores.  Many mushroom volatile compounds are anti-microbial, protecting from infection by bacteria, protists and other fungi. 

Mushrooms also communicate with other fungi, along with bacteria and plants, using their volatile messengers. The volatiles may be telling these other organisms to piss off or to come hither. Or, might tell them something along the lines of “Holy shit, some asshole is digging up the forest…protect yourselves!”.  Mushroom aromatics may stimulate plant growth, which is useful if that plant is the mushroom’s host. Other mushroom aromatics may inhibit plant growth, which may be useful if that particular plant competes with the mushroom’s host plant. 

Volatile chemicals produced by fungi (and bacteria) in the soil can carry out communication long distance by traveling through air pockets in the soil. Tiny amounts of these so-called “semiochemicals” are enough to deliver the message. 

Do mushroom aromas influence us?

Oh yes.  Ever heard of “forest bathing”?  Known as Shinrin-yoku in Japan, forest bathing is an therapy that entails getting thine ass out into nature. The purpose is to appreciate the beauty while doing a little forest aromatherapy. Both of these result in multiple health benefits. Tree aromatics get all the attention, but fungal aromatics are there, too.  That rich, earthy, fungusy scent you’ve probably smelled in the woods comes, indeed, from fungi. One of the most prevalent mushroom volatiles, 1-octen-3-ol (aka. the aforementioned octenol), is sedating and may contribute to the stress relief of walking in the woods.

Then, of course, there are the wonderful scents when cooking after a good forage.  Though heating mushrooms alters many of their aromatic chemicals, they still smell damned good!   Boletes roasting in the oven.  Chanterelles sauteeing on the stove.  Truffle oil…  (OK, I’ve never and never will find a Truffle.)   

Mushroom aromatics are being investigated as anti-bacterial agents, given the distressing and rapid rise in multidrug resistance in pathogenic bacteria. They also have application in food safety as a way to avoid synthetic food preservatives.  Other mushroom aromatics support the respiratory system, and some have anti-cancer activity (in a dish, at least…).  

Not all aromatics produce by fungi are good for us.  An example is the  phenomenon of “sick building syndrome” —  a collection of symptoms such as skin irritation, respiratory distress, fatigue and other fun ones — may be linked in part to fungal volatiles (1). 

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Mushroom Perfume?!

Why not?  The scent of mushrooms goes well beyond “mushroomy”.  If you spend time in nature, you may have encountered Oyster or Horse Mushrooms with their lovely almondy/aniseed scent. (I’ve yet to find Oysters in the grocery store or from a kit with this scent…growing conditions are important.) You Pacific Northwesterners may know the spicy, pungent scent of Matsutake, which has been described by mushroom expert, David Arora, as a “provocative compromise between red hots and dirty socks”. Chanterelle aficionados are familiar with the mushroom’s apricot-like scent, whether stumbling across them in the Doug Fir forests of the PNW or finding them them half hidden under rocks in the Southern Rockies. 

The scent of mushrooms varies wildly and many have distinctively un-mushroomy scents. For example:  Grapefruit and anise (Honey Mushroom); jasmine, rose and fruit (Inocybe species); orange blossom (Flowery Blewit); burnt toffee (Trembling Merulius); pineapple, apples and coffee (Birch Polypore); fruity, banana (Bleeding Broadleaf Crust); and, not to be left out, fish and tallow (Turkey Tails)(2).  

Many volatile chemicals from fungi are used in perfumery. It’s less common for mushroom distillations or other mushroom extracts to be used in perfumery, though some are out there.  You’ll get to smell some mushroom hydrosols and blends in this class. In the  mean time, check out natural perfumer Mandy Aftelier’s Cepes (Boletus edulis) and Tuberose. There’s even a (patented) Bolete essential oil (3).  Bolete is a base note (LINK: https://basmati.com/2017/11/09/essential-oil-essentials-making-natural-perfume-simply): A heavy note that grounds a blend and gives it some heft. The larger molecular size of base notes slows the evaporation of smaller scent molecules in a perfume blend, making the perfume last longer.  The middle notes, of intermediate size, round out a perfume blend. 

OK, back to mushrooms. Quite a few shrooms are rich in top notes, those small scent molecules that evaporate the quickest. Take the most ubiquitous mushroom aromatic, octenol. I assumed that a mushroomy aromatic such as this would be a base note.  Nope. Small molecule. Top note. 

Compared to aromatic plants such as Rosemary, Lavender, Pine and such, mushrooms don’t produce nearly the level of volatile oils. I’ve not been able to isolate mushroom essential oils either with my janky stove-top pot-with-upside-down-lid setup or with my microwave distiller. So I’ve been making hydrosols and infused oils.  We had a non-existent mushroom season in 2018 (after I proposed this class, of course), so I didn’t get to play as many wild mushrooms as I wanted. Though there were conks, of course. You’ll get to smell some mushroom (mostly conk) hydrosols and blends in this class.

Here are some of the most prevalent mushroom aromatics

C8 Compounds

The most common mushroom aromatics are aliphatic eight-carbon (“C8”) compounds. Aliphatic means that the carbons form a chain rather than a ring stucture.  They’re linoleic acid breakdown products (1) found in essentially every mushroom tested, as far as I can tell. C8s are very prevalent in the common grocery store Button Mushroom (Agaricus bisporus), making up from 44 to over 90% of the aromatic molecules (4). This relatively “boring” mushroom actually has over 150 different scent molecules, by the way (4).

A very prevalent C8 aromatic is the aforementioned octenol, which contributes significantly to mushroom scent and flavor. In addition to mushroomy, the scent of octenol has been described as lavender-like, herbal, bright, earthy, buttery, resinous, vegetable and hay-like (2, 5). You’ll get to decide for yourself in the Mushromatherapy class in May. Why such a wide range of descriptors?  Because, molecularly-speaking, octenol has 2 different configurations that result in different scents.

Octenol has a role in mushroom metabolism and sporulation.  It’s also anti-bacterial and anti-fungal (4), protecting the fruiting body from infection by unwanted critters. The scent can act as either an insect repellent or attractant depending on the bug (1). This may serve either to protect the fruiting body from being nibbled on by insects or, instead, to lure in a 6-legged carrier to help spread the mushroom spores afar. (Mushroom pollinators, as it were.)  Mosquitoes are one of the insects that octenol attracts. So, if you find yourself in a campground and there’s a noisy, annoying group there as well, sneak over and spray their camp site with octenol.   

Octenol was sedating in rodent studies (6).  Accordingly, there’s a post on the outstanding mushroom blog Reishi and Roses that describes how ridiculously sedating the aroma of Artist’s Conk was during distillation (7). Octenol is is one of the major aromatics of Artist’s Conk (8).

Aside from mushrooms, octenol is also found in basil, spearmint, thyme, elder flowers, dill, hyssop, lavender, marjoram, oregano, rosemary, sage, lemon balm and others. Lots of mints on the list. I wonder if any of the relaxing quality of mints is related to octanol…   Pumpkins, bananas, black currants and raspberries also contain octenol (5).  And, weirdly enough, octenol’s in our breath, too.  Who knew?  

A related and even mushroomier-smelling C8 is 1-octen-3-one; and there are a slew of other C8s with scents ranging from mushroomy, buttery, nutty, fatty or metallic to floral, lavender-like, sweet, green or vegetable-like (9-10). 

Hexanal

This is the same as “1-hexanal”.

Hexanal is a major volatile component in King Boletes (12), and also lends it’s scent to those aromatic lovelies Chanterelles (13), Matsutake (14) and Oyster Mushrooms (15). Hexanal is also an aromatic in Button and Meadow Mushrooms (16).

This linoleic acid derivative and aldehyde is a yummy top note with a scent described as woody, citrusy, green, fresh, grassy, apple-like and vegetable-like (5).  Again, you’ll get to offer your own 2 cents on this one at the conference.   “Apple-like” isn’t too much of a stretch, given that hexanal’s found in apples. It’s in many other fruits and veggies, too:  Bananas, coconuts, carrots, avocados, cucumbers and a whole passel of citruses (5). Like benzaldehyde, hexanal is a popular natural flavor in the food industry and is also used to flavor rum (5).

Hexanal is also an essential oil component of herbs including parsley, oregano, bay laurel, angelica seed, clove, cayenne, oregano and spearmint.  Coffee and tobacco have it, too (5). It’s a major contributor to the green odor of leaves (17).

Hexanal inhibits plant seed germination and pollination of several plant species (18), making me wonder if some mycorrhizal mushrooms use it to inhibit competitors of their plant hosts.

Hexanal is active against nasty pathogenic bacteria such as E. coli, Salmonella and Listeria (19) and is also anti-fungal (20) and anti-viral (21). On another note, hexanal is emitted by bed bugs when they’re doing it (22). 

Hexanal is detected in the breath of folks with Multiple Sclerosis and is this is being explored as a possible detection/diagnostic test (23). Lipid peroxidation is involved in neurodegenerative diseases, and hexanal is an end product of lipid peroxidation; perhaps a reason it’s detectable in the breath of those with Multiple Sclerosis (23). 

Hexanol

This is frequently found in the literature as 1-hexanol or hexan-1-ol.  

Don’t confuse this alcohol (-ol) with the aldehyde (-al) hexanal. Hexanol is found in Oyster Mushrooms (24), Chanterelles, Truffles (1), Boletes (16) and Matsutake (9). 

As with octenol and hexanal, hexanol is a fatty acid breakdown product.  A top note, hexanol is described as ethereal, fruity, apple, sweet, oily, herbal, green, wine-like; and then it takes a downturn with “slightly goaty” (5). When you smell freshly cut grass, hexanol is one of the things you’re breathing in (25). This one will also be on hand at the conference.  

Hexanol is also found in allspice, apples, bay laurel, bilberry, asparagus, cinnamon, elder flowers, ginger, lavender, orange and violet (5). It’s another popular natural chemical in the flavoring industry and in perfumery (25, 26). It’s being explored as a natural fumigant for fruit due to its antimicrobial effects (27).

It has dose-dependent plant growth stimulating or inhibiting effects depending on the plant (1), again, maybe a way a mushroom influences its surroundings. Hexanol, like octenol and hexanal, acts as a semiochemical transmitting signals among different organisms — fungi, bacteria, plants, insects — in an ecosystem (1). 

Benzoic Acid & Benzaldehyde

Benzaldehyde is a significant contributor to the scent of Oyster Mushrooms (Pleurotus species),  (28), Matsutake (Trichloma matsutake)(29) and the really good-smelling Agarics such as Meadow Mushroom (Agaricus camestris), Horse Mushroom (A. arvensis) and, especially, the Almond Mushroom (A. subrufescens aka A. brasiliensis aka A. blazei…same species based on genetics)(30).  Benzaldehyde is also found in Button Mushrooms and King Boletes (16).

I just ordered a pound of Almond Mushrooms for subjecting hydrosol making and oil infusing. (I’ll likely eat some, too.) Drying does alter the volatile composition of mushrooms, but there should be some good-smelling stuff left. Almond Mushrooms don’t grow in the mountains here in Colorado.  And, well, nothing much did this past season. At least in the Southern Rockies. But you might luck out and find them if you live in Southern Cali. 

Benzaldehyde has a strong scent that is sweet, sharp, bitter, nutty, fruity and maraschino cherry-like, but mostly it smells like almonds. You may have already guessed this based on the name ALMOND Mushroom.  Benzaldehyde is a top note in perfumery (5).  It’s scent and flavor have made benzaldehyde one of the most used chemicals in the flavor industry (31). It’s also got anti-fungal, anti-bacterial and anti-tumor action (31).

Benzaldehyde is found in coffee, cinnamon, Rose family members and also in almonds (are you shocked?) (5).  And, here comes the breath thing again…benzaldehyde is also found in our breath (32). (What’s up with this?!)

When benzaldehyde is oxidized, it becomes it’s cousin, benzoic acid. Benzoic acid has a balsamic scent that you’ll be familiar with if you’ve ever worked with benzoin resin or essential oil. Benzoin has long been used as for respiratory conditions and as a topical treatment for wounds.  These uses stem at least in part from the decongesting action and anti-microbial properties of benzoic acid.  Not surprisingly, benzoic acid is in the same mushrooms as benzaldehyde.

Anisaldehyde

Anisaldehyde is another big one in Oyster Mushrooms (33), and is also in Boletes (16) and a bunch of Agaricus mushrooms (4, 34).

Guess what it smells like?  Aside from the obvious, the strong scent of anisaldehyde is also described as balsamic, hawthorn (?!), powdery, sweet, almond, fruity, berry, chocolate, cinnamon, minty, coumarinic, creamy, spicy and vanilla (5). It’s been reported to have a “typical marshmallow flavor” ) (5), but do they mean the real ones or the hooves and corn syrup version? In either event, that’s a lot of descriptors for one isolated chemical. Not surprisingly, it’s popular in the flavor and perfume industries. It’s makes up a significant fraction of some commercial perfumes (5).

Anisaldehyde has both anti-fungal and anti-bacterial activity (35). It may also increase melanogenesis (pigmentation) in cells (36), which helps cells shield themselves from free radical damage caused by radiation.  Aside from the potential use in prevention of skin cancer, the authors of the study posit that anisaldehyde may be helpful for folks with vitiligo or other conditions wherein the skin loses its pigmentation. 

It’s found in aniseed (surprise!), along with star anise, fennel, basil, cinnamon, dill, cumin, tarragon and pine (I wonder if anisaldehyde is why Ponderosas smell like vanilla or butterscotch when you stick your nose up to the bark and sniff).  Black currant, tea leaves (Camillia sinensis) and vanilla also contain anisaldehyde (5).

Methional

Potato.  That’s what this smells like. And tastes like (it’s a major scent and flavor component of baked potatoes).  Methional is an aromatic found in Oyster mushrooms (24), Giant Puffball (37),  Matstutake (9), Button Mushrooms (38), King Bolete (39) and Truffles (40).

Methional is also described as cheesy (especially limburger!), creamy, earthy, brothy, meaty and savory (5). Accordingly, methional activates the umami taste receptor on the tongue (41). Unlike the other aromatics discussed so far, methional contains sulfur. Sulfur-containing molecules tend towards the stinky.  While the odor descriptor would make me inclined to chuck it in the base note file (“meaty” doesn’t exactly make me think “top note”), it’s actually a very small scent molecule and would be expected to evaporate relatively quickly, thus a top note. Next time you want a McDonald’s-scented body spray, reach for methional!

People and other animals tend to like the flavor and scent. Evolution stepped in and switched some plants to animal rather than insect pollinators, with methional being the lure (42). Maybe mushrooms are using it for the same reason…spreading their spores. We humans certainly help by carrying our Bolete bounty along in a basket. 

Methional is also found in asparagus, tamarind, pumpkins, potatoes (duh!) and some fermented foods (5).  It’s an important contributor to the flavor of cheeses, too. 

These are just a small handful of the gazillion aromatics that mushrooms (or their microbial hangers-on) make, with all sorts of surprising scents.  The focus on those here was simply because they’re some of the more common mushroom aromatics.   And they’re found in some of the mushrooms I’m most familiar with in my practice and my kitchen. 

Next time in Plant Healer Magazine (and also in the Mushromatherapy class at this May’s Confluence), we’ll look more into some wonderful smelly mushrooms. Meanwhile — for further geekery —here are links to databases of fungal (and other) aromatics:

References

1. Hung, R, et al (2015) Fungal volatile organic compounds and their role in ecosystems. Appl Microbiol Biotechnol (2015) 99:3395–3405.

2. Song SC, & JM Birmingham (2015) Mushrooms as a source of natural flavor and aroma compounds. Proceedings – 2nd International Conference on Mushroom Biology and Mushroom Products. Chapter 37.  345-66.

3. Patent (2012) Porcini essential oil, essential oil seasoning and preparing method thereof. https://patents.google.com/patent/CN101744209B/en.

4. Moliszewska, E (2014) Mushroom Flavor.  Folia Biologica et Oecologica. 10:80-8.

5. The Good Scents Company Information System http://www.thegoodscentscompany.com/

6. Ito, K & M Ito (2011) Sedative effects of vapor inhalation of the essential oil of Microtoena patchoulii and its related compounds. J Nat Med. 65(2):336-43.

7. Sitkoff, A (2015) Distillations on Ganoderma applanatum. Reishi & Roses.  https://reishiandrosesbotanicals.com/2015/08/10/distillations-on-ganoderma-applanatum/ 

8. Campos, F, et al (2007) Volatile Metabolites From the Wood-inhabiting Fungi Bjerkandera adusta, Ganoderma applanatum, and Stereum hirsutum. J Essential Oil Res. 22(2):116-118.  

9. Cho, IH, et al (2006) Characterization of Aroma-Active Compounds in Raw and Cooked Pine-Mushrooms (Tricholoma matsutake Sing.) J. Agric. Food Chem. 54 (17), pp 6332–6335.

10. Cho, IH et al (2008) Food Chem. Volatiles and key odorants in the pileus and stipe of pine-mushroom (Tricholoma matsutake Sing).  Food Chem. 106(1):71-6. 

11. Bozok, F, et al (2015) Comparison of volatile compounds of fresh Boletus edulis and B pinophilus in Marmara region of Turkey.  Not Bot Horti Agrobo. 43(1):192-5.

12. Nöfer, J et al (2018) The Influence of Drying Method on Volatile Composition and Sensory Profile of Boletus edulis. J Food Quality Article ID 2158482.

13. Kuka, M, et al (2014) Chemical composition of Latvian wild edible mushroom Cantharellus cibarius. Foodbalt. Conference Proceedings. 248-52.

14. Guo, Y, et al (2018)  Characteristic volatiles fingerprints and changes of volatile compounds in fresh and dried Tricholoma matsutake Singer by HS-GC-IMS and HS-SPME-GC-MS. J Chromatogr B Analyt Technol Biomed Life Sci. 1099:46-55. 

15. Gogavekar, SS, et al (2014) Important nutritional constituents, flavour components, antioxidant and antibacterial properties of Pleurotus sajor-caju. 51(8):1483-91. J Food Sci Technol. 51(8): 1483-91.

16. Rapior, S, et al (1997) Volatile aroma constituents of Agarics and Boletes. Recent Res Dev Phytochem. 1:567-84.  

17. Zhuang, H, et al (1996) The Impact of Alteration of Polyunsaturated Fatty Acid Levels on C,-Aldehyde Formation of Arabidopsis thaliana Leaves. Plant Physiol. 11 1 : 805-812.

18. Gardner, HW, et al (1990) Hexanal, trans-2-hexenal, and trans-2-nonenal inhibit soybean, Glycine max, seed germination. J. Agric. Food Chem. 38 (6):1316–1320.

19. Lanciotte, R, et al (2003) Application of hexanal, (E)-2-hexanal, and hexyl acetate to improve the safety of fresh-sliced apples. J Agric Food Chem. 51(10):2958-63.

20. Song, J, et al (1996) Hexanal vapor is a natural, metabolizable fungicide: Inhibition of fungal activity and enhancement of aroma biosynthesis in apple slices.  J Am Soc Hort. 121(5): 937-42.

21. Patent application (2015) Antiviral activity from medicinal mushrooms and their active constituents. Justia Patents. https://patents.justia.com/patent/9931316 

22. Francke, W, & S Schultze (2010) Pheromones of Terrestrial Invertebrates. Comprehensive Natural Products II. Chemistry & Biology. 4:153-223. Elsevier.  

23. Ionescu, R, et al (2011) Detection of Multiple Sclerosis in exhaled breath using bilayers of polycyclic aromatic hydrocarbons and single wall carbon nanotubes. ACS Chem Neurosci. 2(12): 687–693. 

24. Usami, A, et al (2014) Chemical composition and aroma evaluation of volatile oils from edible mushrooms (Pleurotus salmoneostramineus and Pleurotus sajor-caju). J Oleo Sci. 63(12):1323-32.

25. 1-Hexanol. PubChem Open Chemistry Database https://pubchem.ncbi.nlm.nih.gov/compound/1-Hexanol#section=Top    

26. 1-Hexanol, FooDB http://foodb.ca/compounds/FDB008072

27. Hamilton-Kemp, TR, et al (1996) Metabolism of natural volatile compounds by strawberry fruit. J. Agric. Food Chem. 44 (9), pp 2802–2805.

28. Beltran-Garcia, M, et al (1997) Volatile Compounds Secreted by the Oyster Mushroom (Pleurotus ostreatus) and Their Antibacterial Activities

J. Agric. Food Chem. 45 (10), pp 4049–4052. 

29. Li, Q, et al (2016) Chemical compositions and volatile compounds of Tricholoma matsutake from different geographical areas at different stages of maturity. Food Sci & Biotechnol. 25(1):71-7.

30. Agaricus blazei, Agaricus brasiliensis, Himematsutake http://www.medicalmushrooms.net/agaricus-blazei/.

31. Verma, RS et al (2017) Natural benzaldehyde from Prunus persica (L.) Batsch. Int J Food Prop. 20(52):S1259-63.

32. Clegg, B (2018) Benzaldehyde. Chemistry WorldRoyal Society of Chemistry. https://www.chemistryworld.com/podcasts/benzaldehyde/3009422.article.    

33. Okamoto, K, et al (2002) Biosynthesis of p-anisaldehyde by the white-rot basidiomycete Pleurotus ostreatus. J Biosci Bioeng. 93(2):207-10.

34. Rapior, S, et al (2002) The anise-like odor of Clitocybe odora, Lentinellus cochleatus and                                           Agaricus essettei. Mycologia. 94(3):373-6.

35. Shen, H-S, et al (2017) Antimicrobials from mushrooms for assuring food safely. Comp Rev Food Sci Food Safety. 16:316-329.

36. Nitoda, T, et al (2007) Anisaldehyde, a Melanogenesis Potentiator. Z Naturforsch. 62(1-2):143-9.

37. Leffingwell, JC & ED Alford (2011) Leffingwell Reports, Vol. 4. Feffingwell & Associates. Alford Consulting.

38. Qin, L, et al (2011) Effect of different cooking methods on the flavour constituents of mushroom (Agaricus bisporus (Lange) Sing) soup. Food Sci & Technol. 46(5):1100-08.

39. Guedes de Pinho, P, et al (2008) Aroma compounds in eleven edible mushroom species: Relationships between volatile profile and sensorial characteristics. CIMO – Artigos em Proceedings Não Indexados à WoS/Scopus. 

40. Vita,F, et al (2015) Volatile organic compounds in truffle (Tuber magnatum Pico): comparison of samples from different regions of Italy and from different seasons. Sci Reports. 5: Article number: 12629.

41. Toda, Y, et al (2018) Positive/Negative Allosteric Modulation Switching in an Umami Taste Receptor (T1R1/T1R3) by a Natural Flavor Compound, Methional. Sci Rep. 2018 Aug 7;8(1):11796.

42. Wester, P, et al (2019) Scent chemistry is key in the evolutionary transition between insect and mammal pollination in African pineapple lilies. New Phytol. doi: 10.1111/nph.15671.

Went looking for mushrooms today. Found nothing but a few Corts : ( But I did find a lovely patch of Monkshood (Aconitum columbianum), one of my favorite wildflowers (for just looking at!) around here.

Monkshood contains alkaloids such as aconitine, mesaconitine, and related molecules the toxicity of which manifests in the nervous system and heart, with some GI stuff as well…vomiting, nausea, diarrhea. Aconitum species do have a history of use in Traditional Chinese Medicine and elsewhere after very careful processing and with very careful dosing. (Even handling the plant can result in some neurotoxic effects.) It is deadly in high enough dosage and is not a plant to experiment with.

In other words, don’t stick it in your mouth. Just look at it and marvel at its beauty