Posted by I recently came across an interesting commercial deodorant that caught my attention for a rather unusual reason: it claims to control body odor through quorum quenching (QQ) rather than by simply killing bacteria (though it contains antimicrobial agent as well), blocking perspiration, or masking the smell.
The product is UNODOR™ Deodorant, marketed by Hydendron, Korea, as a “High-Tech Bio Deodorant.” According to the manufacturer, the product uses “Quorum Quenching Technology” to regulate the microbial balance of the skin and reduce body odor at its source. Here is the product website:
https://unodor.shop/products/unodor-deodorant?variant=52407752655137
What made me particularly interested, however, was the ingredient list.
Among the ingredients, one immediately caught my eye:
Hydroxypropyl cyclodextrin (HPβCD).
The complete ingredient list includes butylene glycol, glycerin, triethyl citrate, dipropylene glycol, xylitol, fragrance, hydroxyacetophenone and several other conventional cosmetic ingredients.
So, is this a case where a cyclodextrin is being used for quorum quenching?
First, what is quorum quenching?
Quorum sensing is a bacterial communication mechanism. Bacteria can produce and detect small signaling molecules, allowing them to coordinate their behaviour once the local bacterial population reaches a certain density.
These signals can regulate processes such as biofilm formation and the production of various metabolites and virulence factors.
Quorum quenching (QQ) is the disruption of this communication system. Importantly, it is conceptually different from conventional antibacterial activity: instead of necessarily killing the bacteria, QQ aims to interfere with the signalling processes that allow them to coordinate their behaviour.
This makes the concept particularly attractive for applications involving the microbiome, where indiscriminately eliminating bacteria may not be desirable.
And this is exactly the angle taken by UNODOR. The manufacturer states that its deodorant does not rely on aluminum compounds to block sweat glands or on antibacterial agents to eliminate bacteria. Instead, it claims to disrupt signalling between microorganisms and thereby address body odor.
And where does cyclodextrin come in?
This is the intriguing part.
The ability of cyclodextrins forming inclusion complexes has already made cyclodextrins useful in deodorants and odor-control products. In fact, cyclodextrin-containing deodorant compositions have been described in patents for decades, with the underlying concept being the complexation of odor-causing molecules. HPβCD is also widely used in deodorant and odor-control formulations.
But that is not the same thing as quorum quenching.
And this distinction is important.
Is HPβCD actually a quorum quencher?
The UNODOR website does not explicitly state that the quorum-quenching effect is caused by HPβCD. It describes the product’s mechanism in terms of “Quorum Quenching Technology” while listing HPβCD among the ingredients.
That leaves several possibilities.
HPβCD could potentially be involved in the proposed mechanism – for example, through molecular recognition and sequestration of signalling molecules. Alternatively, another component of the formulation could be responsible for the claimed biological effect or the formulation could rely on a combination of mechanisms.
There is also a more straightforward possibility: HPβCD may simply be there for its well-established odor-control properties, while the quorum-quenching claim is based on another aspect of the formulation.
At present, I would therefore describe the connection between HPβCD and QQ as an interesting hypothesis rather than an established fact.
The proposed mechanism is not inherently implausible [1,2]. Cyclodextrins are molecular hosts, and bacterial quorum-sensing molecules are small organic molecules. In principle, host–guest interactions could affect the availability of signalling molecules.
Whether this actually occurs at relevant concentrations, under the conditions present on human skin, and whether it produces a meaningful biological quorum-quenching effect is a completely different question, still theoretically feasible.
[1] Kato, N.; Morohoshi, T.; Nozawa, T.; Matsumoto, H.; Ikeda, T.
“Control of Gram-negative bacterial quorum sensing with cyclodextrin immobilized cellulose ether gel.” Journal of Inclusion Phenomena and Macrocyclic Chemistry 2006, 56, 55–59.
DOI: 10.1007/s10847-006-9058-5.
[2] Molnár, M.; Fenyvesi, É.; Berkl, Z.; Németh, I.; Fekete-Kertész, I.; Márton, R.; Vaszita, E.; Varga, E.; Ujj, D.; Szente, L. “Cyclodextrin-mediated quorum quenching in the Aliivibrio fischeri bioluminescence model system – Modulation of bacterial communication.”
International Journal of Pharmaceutics 594 (2021), 120150.
DOI: 10.1016/j.ijpharm.2020.120150.