According to a 2001 study published by Shiseido in the Journal of Investigative Dermatology, nonenal is an unsaturated aldehyde detected only in subjects over 40 years old.
The same study concluded that nonenal tends to increase with age and hypothesised that it could be the culprit behind age-related change of body odour.
Nonenal has been described as an ‘unpleasant greasy and grassy odour’. In Japan, this unique odour has been dubbed kareishū, which translates to ‘ageing odour’.
This year, the cosmetic company published another study in Biochemical and Biophysical Research Communications suggesting that it is not just our noses that are sensitive to nonenal.
According to Shiseido, our skin can also sense the changes in body odour. Previous studies have shown that scent does affect the physiology of the body and the condition of the skin, but in many cases, the direct effects of scents on the skin have not been clarified.
In order to investigate the effect of nonenal on the skin, the team conducted an experiment on cultured human keratinocytes. Nonenal was observed to decrease the viability and promoted apoptosis, or cell death.
Furthermore, using a 3D epidermal model, the researchers also observed that nonenal reduced skin thickness and the number of proliferative cells.
As previous studies have shown that skin tends to become thinner with age, the results of this experiment also suggest that nonenal may be involved, said researchers.
“It can be seen that when 2-nonenal l is added and cultured, the thickness of the epidermis is clearly reduced. When the skin is very thin, it may not be able to fully exert its original physiological functions.”
Scent of youth
In order to suppress skin damage caused by nonenal, the team experimented with fragrances that could mask the scent of nonenal.
The team developed a masking fragrance with six components: dihydromycenol, benzaldehyde, linalool, phenethyl alcohol, benzyl acetate and anisaldehyde.
When tested on the cultured human keratinocytes, the researchers observed that the damage to the cells was suppressed.
Next, the same masking fragrance was tested on the 3D epidermal model, and it also managed to prevent the epidermis from thinning.
“In other words, it can be said that the complex aroma fragrance not only makes the scent of 2-nonenal inconspicuous, but also has the effect of suppressing skin damage,” the researchers concluded.
They added that inhibitory effects of masking fragrance on 2-nonenal have opened the doors to a “completely new approach” to maintaining the health and appearance of skin.
“This is a new discovery that combines dermatology and fragrance science. Going forward, we will continue to deepen our research on the effects of each customer's skin and the external environment and propose new approaches to achieve healthy and beautiful skin.”
Source: Biochemical and Biophysical Research Communications
Authors: Nakanishi et al.
https://doi.org/10.1016/j.bbrc.2021.02.050