Catherine Kern, Elsa Hernandez, Christian Gombert, Christine Garcia
2020, SEPAWA® congress & FORUM COSMETICUM
Skin microbiota is essential for healthy skin. Dysbiosis between microbiota and skin leads to inflammation and dysfunction of the barrier function, and to the development of skin disorders, such as dryness or sensitivity. Our aim was to investigate the effect of ArL, an Arctium lappa root extract, on protection and comfort of reactive skins, by acting on microbiota equilibrium and skin barrier function. The efficacy of ArL on skin barrier function was evaluated on reconstructed human epidermis colonized with Staphylococcus epidermidis, the most common bacteria of the cutaneous microbiota, and Staphylococcus aureus, a pathogen which can cause skin infections. ArL limited S.aureus biofilm formation, without impacting its viability nor that of S.epidermidis. ArL also reinforced skin barrier function evaluated by TransEpithelial Electrical Resistance and histology. The effect of ArL on microbiota balance was further analysed by assessing its ability to modulate inflammation resulting from perturbation of skin-microbiota system, based on activation of Toll-Like Receptors in keratinocytes. ArL was able to protect keratinocytes from IL-8 and hBD2 overproduction and thus to regulate inflammation in such conditions. A disequilibrium in skin microbiota such as Cutibacterium acnes proliferation can also induce lipid overproduction by sebocytes and thus skin inflammation. A reduction of lipid droplet formation in stimulated sebocytes was also observed and corroborated the ability of ArL to modulate inflammation induced by microbiota imbalance. A clinical study on sensitive skins confirmed a soothing effect of ArL-containing formula in comparison with placebo. A reduction of skin redness and stinging/burning sensations was observed after 14 days of application. Another clinical study showed a moisturizing effect of ArL-containing formula in comparison with placebo after 7 and 21 days of application. In conclusion, ArL can promote balance and comfort of reactive skins, likely by strengthening skin barrier and contributing to microbiota balance.
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