The potential prebiotic effect of 2‐Butyloctanol on the human axillary microbiome

Abstract

Objective:The human axilla is colonized by a wide array of microorganisms that contribute to the generation of body odour. Traditional antiperspirant/deodorant products are used to reduce perspiration in the axillary region and to treat or prevent the growth of bacteria in this region, thereby reducing or eliminating body odour. However, they may also compromise the axillary microbiome balance.The personal care industry has been seeking new ingredients, such as prebiotics or probiotics, to maintain a healthy balance of the skin microbiome by inhibiting odour-causing bacteria, whilst maintaining and promoting the growth of good bacteria. The aim of this study was to investigate the prebiotic effect of a skin-care ingredient, 2-butyloctanol, on the human axillary microbiome.Methods: An in vitro growth inhibition/promotion assay was performed to test whether 2-butyloctanol inhibited or promoted skin bacterial growth. The impact of 2-butyloctanol on the axillary microbiome was also investigated in a human clinical study using 16S rRNA gene sequencing. Results:In-vitro testing showed that 2-butyloctanol significantly inhibited the growth of corynebacteria at concentrations of 0.64%, 2.56% and 5.12%, whilst the growth of Staphylococcus epidermidis was maintained at the same concentrations. The impact of 2-butyloctanol on the axillary microbiome was also validated in a human clinical study. A deodorant roll-on product containing 3% of 2-butyloctanol significantly reduced the relative abundance of corynebacteria, whilst increasing the relative abundance of Staphylococcus and the ratio of Staphylococcus to corynebacteria after four weeks of application, whilst the placebo showed no significant change. Conclusion:For the first time, it was demonstrated that 2-butyloctanol had a potential prebiotic effect on the human underarm microbiome in inhibiting odour-causing Corynebacterium, whilst maintaining and promoting skin-friendly Staphylococcus in both in-vitro and in-vivo studies. Therefore, 2-butyloctanol could be used as a potential prebiotic ingredient in personal care products for underarm microbiome protection.

Using surface-enhanced Raman scattering for simultaneous multiplex detection and quantification of thiols associated to axillary malodour

“…19 As key biomarkers of bacterial metabolism, and the primary causative agent in the generation of axillary malodour, the accurate detection and quantification of these thiol-based odorants is essential for efficacy testing of cosmetic products such as deodorants and anti-perspirants, designed to reduce thiol generation. [20][21][22] Currently, the main methods involved for detecting and quantifying these thiols and VFAs is by GC-MS. 12,15,[23][24][25] In previous research, GC-MS has sometimes been used with a sniff port attached and using volunteers for qualitative detection. 6,26,27 GC-MS is used due to its high sensitivity, selectivity and being able to examine the data quantitatively.…”

The impacts of sodium lauroyl sarcosinate in facial cleanser on facial skin microbiome and lipidome

“…[21][22][23] Skin care products can change the abundance and structure of microorganisms and lipids, thereby affecting the ecological balance of the skin. [24][25][26][27][28] Chemical surfactants are common ingredients in skin care products, and serve as emulsifiers, solubilizers, and detergents in creams and lotions. 29,30 Surfactants can bind with proteins, remove lipids from the epidermal surface, contribute to the disorganization of liquid crystal structures in the intercellular lipids, and interact with living skin cells.…”

“…Factors affecting the skin environment include both individual endogenous factors, such as skin area, age, gender, and race, 18–20 and exogenous factors, such as UV, humidity, pollution, environmental bacteria, and cosmetics 21–23 . Skin care products can change the abundance and structure of microorganisms and lipids, thereby affecting the ecological balance of the skin 24–28 . Chemical surfactants are common ingredients in skin care products, and serve as emulsifiers, solubilizers, and detergents in creams and lotions 29,30 .…”