Orange Blossom by Dr. Elise Pearlstine© Editor

What gives florals their seductive power? Let me introduce you to a compound called indole.

Indole is, by definition, an aromatic heterocyclic compound which contains a six-membered benzene ring, fused to a five membered nitrogen-containing pyrrole ring.

 

Indole

 

If that doesn’t mean much to you, here’s the what you need to know; it smells.

But, perhaps poop isn’t the best description for indole. In its pure, isolated form, Indole is more like a musty, wet, yet also a penetrating sharp-clean smell. A sort of odd combination of wet-dog, stale hot breath and moth balls all rolled into one.  Yes, this compound does contribute to the smell of feces ( mixed together a cornucopia of other things ) but trace amounts are also founds in “White” florals, like Jasmines, Tuberose, Neroli, Orange Blossom Gardenia, etc.  What really creates the signature aroma of #2 is really when high concentrations of indole are mixed with humidity and the surrounding decaying molecules found in poop.

Gardenia by Dr. Elise Pearlstine©

Here’s the interesting part – In trace amounts ( around >1% ),  the stench of pure indole actually mellows, losing the mustiness and becoming more “floral”, more ambient. In perfume, natural oils that contain indole are often used to bring intrigue and a seductive edge to a scent. Providing an indescribable, underlying “animalic” note that allures to the primal senses, similar in a way to how pheromones work.

 

 Marcel Duchamp’s Fountain, 1917, via Wikimedia Commons

When it comes to perfume, indole serves a new purpose… It seduces.

I am a little embarrassed to write this, but poop can be sexy. It’s similar to being in a public restroom and having the unfortunate experience of smelling someone else’s last ‘performance’.  It’s repulsive and visceral, but at the same time a small part of you is extremely curious, a little intrigued in a primal way-  a “what IS that? What did they eat? Do I smell like that?“-  sort of way. It’s biological- look at animals. Anyone who has ever lived with dog will tell you that they sniff poop. This helps them gain information about who this dog is, what they ate, are they healthy enough to mate with, etc. This sort of poop-information-finding technique rings true though many mammals.

Jasmine Auriculatum by Dr. Elise Pearlstine©

White Florals are dirtiest.

White florals are just that – white. Gardenia, Jasmines, Hyacinth, Tuberose, Orange blossom all fall into this category of being extremely rich in indoles. However a few other friends in the flower kingdom also hold trace amounts of the compound, such as rose, lilac and honeysuckle.

Jasmine, however, might be the dirtiest.

 Jasmine Grandiflorum stock photo

The essences of Jasmine, particularly the variety Jasmine Grandiflorum, is notorious for having a noticeable, STRONG indole note ( most jasmine oils contain around 2.5% of the pure stuff ). By no means do it smell like sniffing a toilet, but when faced with a pure jasmine oil, indole does bring a very noticeable wet- mustiness aroma, much like dirty, sweaty skin mixed into the narcotic floral-sweetness of fresh jasmine blooms. It can be unnerving in a way- it really makes you question you perception of scent and what is true. But this is where dilution makes things interesting. 

As mentioned above, pure jasmine oil is roughly 2.5% pure indole. That’s a noticeable amount to any nose.  But, think of the last time you’ve walked by blooming jasmine ( or even smelled a white lily or wild honeysuckle ). The scent is very pleasant, sweet, floral, seductive. Indole is in there, but in such a limited amount, that it only adds a seductive, “alive” quality that you come to associate with florals. There’s nothing toilet-y about it.

 Jasmine Enfleurage by Dr. Elise Pearlstine©

Now take about 10,000 lbs of those jasmine flowers, and distill them into 2.2lbs of oil. All the same fragrant molecules are there, just much more concentrated. With indole being present at a more condensed level, the sexy-sultry edge of fresh flowers, now becomes muddled with a much mustier, dirty undertone. The key to indole’s seduction is in dilution.

 

stock photo from Sr Ida Meister’s article How I learned to love my own Amygdala.

Indole and Serotonin

Perhaps the most interesting thing about Indole is its relationship to Serotonin. Indole is an intermediate that helps compose the the amino acid Tryptophan. Tryptophan is a precursor to the calming neurotransmitter serotonin. In short, the “indole ring”, as described in the beginning of this article, is found in the calming/happy serotonin chemical, also found in anti-depressants and foods like chocolate, dairy products and pumpkin seeds.

Not without controversy, Indole can be a polarizing scent.  While some love the sometimes sharp, animalic edge it provides, others find it to be troublesome and cause headaches.  For the indole-adverse crowd; There are non-indolic white floral scents out there- however they are generally not always natural. Synthetics fragrances can be synthesized without the indole compound or naturals can be fractionated to have it removed. All equally floral in their own right, however they can be a little flat and dry. That special, sparkling, life-like quality that REAL flowers exude is lost without the inclusion of our peculiar friend, Indole. So let’s appreciate this molecule for all the life that they bring to the party.

Dirty, musty, and full of life. Thank you, indole.

This post originally published on MIZUbrand.com

–Mason Hainey of MIZU, Natural perfumer and Guest Contributor, Website: MIZUbrand.com

Dana Tabu & Gloria Grahame as Debby in The Big Heat (1953) (Copyright: Columbia Pictures/Sony Pictures Home Entertainment) collage by Despina Veneti© used in her Perfumed Plume award winning essay Fragrances of Film Noir: Scenting Five Femme Fatales

Joy de Patou (worn by Josephine Baker)  is a notoriously indolic jasmine perfume, Dana Tabu has a highly indolic orange blossom heart and Fracas de  Robert Piguet is the Queen of indole in Tuberose, composed by the legendary Germaine Cellier in 1948

*additional photos and information from CaFleureBon Editors, Elise Pearlstine, Ermano Picco, Despina Veneti and Michelyn Camen

Instagram: @mizubrand  @cafleurebon @elisepearlstine