SKIN MICROBIOME
significantly inhibited histamine release by 54% (Fig 2). Interestingly, histamine is also known to be a stimulator of sebum secretion.12
Therefore, by
inhibiting histamine release, the active ingredient should reduce sebum production in addition to reducing scratching, thus resulting in an improvement of sensitive scalp conditions. We confirmed this effect at the clinical level as we showed that the active ingredient significantly inhibited scalp sebum production by 20.4%, while the placebo had no effect. To complete this clinical study, a survey on the
feelings of the volunteers after 28 days of product use was conducted. 80% of volunteers who used the shampoo with the active ingredient declared a feeling of scalp soothing in comparison to only 60% for placebo group, supporting the anti- irritation activity of the active ingredient.
An active ingredient mild to the scalp microbiota The scalp, such as the skin, is populated by a large variety of bacteria that compose its microbiota. This microbiota helps maintain scalp’s physiology and healthiness. As mild scalp sensitivity is not considered to be a pathological condition, a cosmetic active ingredient should not disturb its balance. Indeed, modifying it could generate additional scalp issues. Therefore, we wanted to demonstrate that the extract of apple stem cells does not modify the diversity and the number of live bacteria on the scalp. To do so, we collected swabs before and after the active and placebo treatments were applied in order to quantify the viable bacterial community. Figure 3A shows that bacterial population
density is not modified either by the use of placebo, nor by the active, suggesting that the active respects the scalp microbiota while being an efficient scalp soother. As the main bacterial species living on the
scalp belong to the genera of Cutibacterium and Staphylococcus, we focused our analysis on the species of these genera. For that, thanks to mass spectrometry, the species were identified, then the relative proportions of Cutibacterium species and Staphylococcus species were determined by scoring. Figure 3B shows no significant variation on the main species of Staphylococcus and Cutibacterium whether with the active or with the placebo.
1000 800 600 400 200 0
Control A23187 A
6000 5000 4000 3000 2000 1000 0
B (ns) (ns)
3.5 3
2.5 2
1.5 1
D0 D2 D08 Placebo
D28 Active ingredient Placebo Active ingredient
Figure 3: Effect of the active vs placebo on scalp microbiota. A: total numbering of viable microorganisms; B: Identification and quantitative scoring of bacteria from the surface of scalp. Statistics: ns: non-significant.
These studies demonstrate that while being effective at soothing sensitive scalp (which the placebo is not), the apple stem cell extract respects the scalp microbiota main populations, avoiding microbiota imbalance that might cause new unwanted scalp issues.
Conclusion Through this study, Clariant Active Ingredients demonstrated that an extract from apple stem cells used at 2% in a shampoo formula for 28 days can efficiently relieve sensitive scalps by addressing the biological processes that lead to irritation. By sampling cells with a non- invasive method directly at the surface of the scalp and dosing IL-1Ra and S100A8/9, two key markers of irritation, it was demonstrated that the active ingredient reduces their levels to keep irritation under control. The study also demonstrated the active ingredient inhibits the release of histamine, a major itching and inflammatory molecule, thus limiting inflammation and sebum production. All these activities visibly improved visible signs of sensitive scalp such as redness and squames. In addition, it was demonstrated that the active ingredient does not disturb the scalp’s microbiota as it does not affect the population of Staphylococcus spp. and Cutibacterium spp., major commensal scalp bacteria.
PC
References 1 Araviiskaia E, Berardesca E, Bieber T, et al. The impact of airborne pollution on skin. J Eur Acad Dermatol Venereol. 2019; 33(8):1496-1505.
2 Godse K, Zawar V. Sensitive scalp. Int J Trichology. 2012;4(2):102-104.
3 Dowlati Y., Firooz A., Zartab H. Scalp sebaceous physiology, in Agache’s measuring the skin. Springer (2017).
4 Zouboulis CC. Acne and sebaceous gland function. Clin Dermatol. 2004;22(5):360-6.
5 Bin Saif GA, Ericson ME, Yosipovitch G. The itchy scalp--scratching for an explanation. Exp Dermatol. 2011;20(12):959-968. 6 Grimalt R. A practical guide to scalp disorders. J Investig Dermatol Symp Proc. 2007;12(2):10-4
7 Polak-Witka K, Rudnicka L, Blume-Peytavi U, Vogt A. The role of the microbiome in scalp hair follicle biology and disease. Exp Dermatol. 2020;29(3):286-294.
8 Huang WC, Chang WT, Wu SJ, Xu PY, Ting NC, Liou CJ. Phloretin and phlorizin promote lipolysis and inhibit inflammation in mouse 3T3-L1 cells and in macrophage- adipocyte co-cultures. Mol Nutr Food Res. 2013;57(10):1803-13.
9 Perkins MA, Cardin CW, Osterhues MA, Robinson MK. A non-invasive tape absorption method for recovery of inflammatory mediators to differentiate normal from compromised scalp conditions. Skin Res Technol. 2002;8(3):187-93.
-17%** -44%* -54%*
10 Kim MJ, Im MA, Lee JS, Mun JY, Kim DH, Gu A, Kim IS. Effect of S100A8 and S100A9 on expressions of cytokine and skin barrier protein in human keratinocytes. Mol Med Rep. 2019;20(3):2476-2483.
11 Inami Y, Andoh T, Sasaki A, Kuraishi Y. [Surfactant-induced itching and the involvement of histamine released from keratinocytes]. Yakugaku Zasshi. 2012;132(11):1225-30. Japanese.
ingredients
+0.005% Active
A23187 ingredients
A23187 +0.01% Active
ingredients
Figure 2: Effect of the active ingredient on histamine release (mast cells model). Statistics: **: p<0.01, *: p<0.05
www.personalcaremagazine.com
A23187 +0.02% Active
12 Pelle E, McCarthy J, Seltmann H, Huang X, Mammone T, Zouboulis CC, Maes D. Identification of histamine receptors and reduction of squalene levels by an antihistamine in sebocytes. J Invest Dermatol. 2008;128(5):1280-5.
May 2021 PERSONAL CARE
0.5 0
D0 D28 D0 D28 D0 D28 D0 D28 (ns) (ns)
27
(ns)
(ns)
Histamine (ng/mL)
Number of bacteria (UFC/4cm2
)
Scoring
Straphylococcus spp.
Cutibacterium spp.
Staphylococcus spp.
Cutibacterium spp.
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