SKIN CARE 29
cosmetic masking of symptoms. In formulation terms, ingredients able to reduce the intensity of these signals may help interrupt the self- reinforcing cascade in which irritation generates more inflammatory signaling, which in turn delays barrier normalization and prolongs discomfort. A second mechanistic layer involves
cyclooxygenase-2. Ginger-derived constituents are of interest in soothing systems because they may influence lipid-mediator pathways that sit alongside cytokine biology. In internal testing, the ginger component reduced COX-2 enzyme activity by 89% (Figure 3). This observation is highly relevant given that
COX-2 is a rate-limiting enzyme in prostanoid biosynthesis, linking arachidonic acid metabolism to inflammatory amplification. The importance of this pathway is reinforced by pollution literature showing that particulate matter can induce ROS generation, activate MAPK, NF-κB, and AP-1 signaling, increase COX-2 and PGE2, and impair barrier-associated proteins such as filaggrin.9 Together, the cytokine and COX-2 findings support a more cohesive interpretation of soothing efficacy. The blend does not address one biochemical route in isolation; it appears to influence both cytokine-led and lipid mediator- led components of irritation. That dual relevance strengthens its suitability for skin exposed to repetitive or mixed stressors rather than a single acute challenge.
Barrier biology and the importance of COL17A1 An effective soothing story becomes more compelling when inflammation is linked to barrier competence. A growing body of literature shows that ageing and environmental stress affect not only epidermal lipids and junctions, but also stem-cell-associated structures required for epidermal renewal.5–7,10–12
Among these, collagen
XVII, encoded by COL17A1, has emerged as a particularly interesting marker. COL17 is a transmembrane component of hemidesmosomes in basal keratinocytes and contributes to the anchoring and functional
100% 80% 60% 40% 20% 0%
100 90 80 70 60 50 40 30 20 10 0
Control (neg.)
*** Dexamethasone ■ -48% *
-36% p = 0.156
*** -106%
Control (stim.)
0.20 (%)
0.05 0.20
Bisabolol (%)
Dexamethasone ■
70 60 50 40 30 20 10 0
Control (neg.)
Control (stim.)
-13% -71% 0.2 0.1
0.00004 (%)
0.0000056 0.000056 0.00056
Bisabolol (%)
0
Control (neg.)
Control (stim.)
-105% 0.3
1600 1400 1200 1000 800 600 400 200 0
Control (neg.)
Dexamethasone ■ -13% ***
-33% *
-97% ***
Control (stim.)
0.20 (%)
0.05
0.20
Bisabolol (%)
Dexamethasone ■ -10% -47% -64%
0.00004 (%)
0.00001
0.0001
Bisabolol (%)
Figure 2: Bar graphs depict cytokine level in primary human Keratinocytes cultured as monolayers pre- incubated for two hours with α-bisabolol at respective concentration. Induction of inflammation was achieved with PMA and calcium ionophore for 24 hours. Dexamethasone was used as positive control. Cytokine levels were determined by ELISA
behaviour of epidermal stem-cell niches.5,7 Beyond adhesion, it has been linked to proliferation control, regenerative capacity, and maintenance of epidermal architecture. Reduced expression of COL17A1 has been documented in naturally aged, photoaged, and acutely UV- irradiated human skin, where it correlates with features of epidermal decline such as thinning and impaired regenerative potential (Figure 4).6 Figure 4 shows the localization of COL17A at the basal Keratinocyte layer. There, it facilitates
-89%
adhesion of basal keratinocyte stem cells to the basal membrane via hemidesmosomes. During stress and ageing COL17A is decreased
resulting in detachment of basal keratinocyte stem cells and subsequent differentiation and desquamation. Thus, basal keratinocyte stem cells are lost. When stem cells are lost, skin regeneration and homeostasis deteriorate resulting in delayed wound healing, epidermal thinning and impaired barrier function. This makes COL17A1 highly relevant to sensitive
0.001
-47%
-12% 0.00003 0.0003 Ginger Extract (%)
Figure 3: Bar graph shows COX-2 inhibition in presence of ginger extract. Therefore, recombinant COX-2 is incubated with ADHP and arachidonic acid to produce fluorescent resorufin as a measure for COX-2 activity in presence of test substances
www.personalcaremagazine.com 0.003
Figure 4: Illustration of the localization of COL17A at the basal Keratinocyte layer May 2026 PERSONAL CARE MAGAZINE
Mean COX-2 inhibition (%)
IL-1α (pg/well)
IL-6 (pg/mL)
TNF α (pg/well)
IL-8 (pg/mL)
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