54 SKIN MICROBIOME The fresh samples were pooled resulting in
a female and a male sweat sample. Aliquots of untreated and samples treated with propanediol caprate (3000 ppm and 5000 ppm) were subjected to further analytical steps (microbial composition, sniffing test, and analytics) of fresh sweat (0h) and of sweat aged at body temperature (24h, 48h).
Microbial composition The analysis of the microbial composition was done using amplicon metagenomics sequencing. Therefore, the bacterial DNA was isolated from the sweat samples (150 µl pure sweat) (Microsynth; Balgach). Two-step PCR libraries were prepared from the DNA samples using primer set 341F -802R. The resulting fragments were sequenced on Illumina MiSeq 2*250bp. Data analyses for taxonomic classification
(OTUs) of the bacteria were conducted. OTUs were ordered according to the presence of genus information. Most abundant genera (adding up to at least 99% of all detected OTUs) were selected based on total abundance in all experiments and visualized by their relative abundance.
Sensory analysis Sweat samples of the time points 0h, 24h, and 48h were evaluated for odour intensity by an expert panel on a scale from 1 (“no sweat odour”) to 5 (“strong sweat odour”). Samples were randomly assigned to sets
of four, including negative (untreated, 0h incubation) and positive (untreated, 48h incubation) controls besides two test samples. Each sample was applied to smelling strips and evaluated by the panelists.
Chemical analysis To determine the content of glutamine derivatives (odourless precursor molecules) and the corresponding cleaved products (odour- causing compounds), a LCMS/MS-method was established using reference spectra (Agilent HP 1290 LC system). This method was applied for the
determination of the acid content in the sweat
Unassigned/Underrepresented genera ■ Arthrobacter ■ Enterococcus ■ Propionibacterium ■ Peptoniphilus ■ Corynebacterium ■ Staphylococcus ■ Anaerococcus ■
0h
100 80 60 40 20 0
24h 48h
Figure 1: Microbiome analysis (16S rRNA gene sequencing) of sweat samples untreated and treated with SymDeo PMD green (INCI: Propanediol Caprate). *Amount of active in pure sweat [ppm]. This concentration is estimated to be lower than a typical resulting concentration on skin from 0.3% cosmetic use throughout the day
samples after 0h, 24h, and 48h. Small volatile carboxylic acids were enriched, and the single components were measured by GC-MS. The data were analyzed using Microsoft Excel and for the comparison, the 20 most relevant compounds were visualized in a diagram.
In vivo study To compare the deodorant performance of propanediol caprate to the positive control SymDeo B125 (INCI: 2-methyl 5-cyclohexylpentanol),7,8
untreated and placebo
conditions in ‘real application’, an in vivo study was conducted. In this study, a sensory evaluation by a
Sniff Test before and after one application at t= 6h, 24h, and 48h was executed by trained assessors. An odour scale from 0 (0= no odour) to 5 (5= very high odour) was applied. The concentration of the test product was 0.3% for propanediol caprate and 0.3% for 2-methyl
0h 5
4.5 4
3.5 3
2.5 2
1.5 1
0.5 0
Ex vivo panel 1: male sweat 24h
5-cyclohexylpentanol in ethanol/water (40/60). The number of subjects was 3x22 with distinct perspiration odour in the underarm (not less than 3 on the odour scale). A conditioning period of seven days was carried out before product application in which only the use of unscented soap without an anti-bacterial ingredient was allowed and no antiperspirant/ deodorant or other cosmetics was applied. Subjects were told to wear clothing not treated with perfumed detergent or softener. On the eighth day, a sniffing assessment
of the underarm after 6h, 24h, and 48h after washing (t0) was conducted. Left versus right underarm was compared. Thereby 22 volunteers applied 0.3% 2-methyl 5-cyclohexylpentanol versus 0.3% propanediol caprate at random under the left and right armpit.
Results To assess the three-dimensional (3D)
48h 5
4.5 4
3.5 3
2.5 2
1.5 1
0.5 0
0h
Ex vivo panel 1: female sweat 24h
48h
Figure 2: Sensory analysis of sweat samples untreated and treated with SymDeo PMD green (INCI: Propanediol Caprate). Ex vivo sweat odour rating (mean values) by sniffing on a scale from 1 (no odour at all) to 5 (very intense odour), by 5 individual evaluators (Symrise expertise)
PERSONAL CARE October 2024
www.personalcaremagazine.com
Odor Intensity
Untreated
Untreated
PMD green 3000 ppm
SymDeo
Untreated
PMD green 3000 ppm
SymDeo Untreated
Odor Intensity
Untreated
Untreated
PMD green 3000 ppm
SymDeo
Untreated
PMD green 5000 ppm
SymDeo
PMD green 3000 ppm
SymDeo Untreated
Untreated
PMD green 3000 ppm
SymDeo
PMD green 3000 ppm
SymDeo
PMD green 5000 ppm
SymDeo
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