The combination of allantoin, bisabolol, D-panthenol and dipotassium glycyrrhizinate mitigates UVB-induced PGE2 synthesis by keratinocytes.

Abstract

Erythema, characterized by the redness of the skin, is a common skin reaction triggered by various endogenous and exogenous factors. This response is often a result of the activation of underlying inflammatory mechanisms within the skin. The objective of this study is to investigate the potential benefits of applying a combination of skincare ingredients, namely allantoin, bisabolol, D-panthenol and dipotassium glycyrrhizinate (AB5D), in the modulation of inflammatory factors associated with erythema. Additionally, the study aims to elucidate the mechanisms by which these ingredients exert their combined actions to alleviate erythema-associated inflammation. Human epidermal keratinocytes were exposed to UVB and subsequently treated with AB5D. Transcriptomics profiling was performed to analyse the dose-response effect of AB5D treatment on keratinocytes. The quantitation of inflammatory mediators, including PGE2, IL-1α, IL-6, IL-8, IL-1RA and TNFα, was performed on cultured media. Additionally, the oxygen radical absorbance capacity (ORAC) assay was carried out to evaluate the total antioxidant capacity of both individual ingredients and the AB5D combination. To assess the in-vitro antioxidant effects of AB5D against UVB-induced oxidative stress in hTERT keratinocytes, real-time quantitation of mitochondrial superoxide was measured through live-cell imaging. The application of AB5D to UVB-exposed keratinocytes downregulated gene sets associated with inflammatory responses, highlighting the anti-inflammatory properties of AB5D. Specifically, AB5D effectively reduced the production of PGE2, leading to the downregulation of inflammatory cytokines. Moreover, our findings indicate that AB5D exhibits antioxidative capabilities, functioning as both an antioxidant agent and a regulator of antioxidant enzyme expression to counteract the detrimental effects of cellular oxidative stress. We demonstrated that AB5D can reduce UVB-induced PGE2, IL-1α, IL-6, IL-8, IL-1RA and TNFα as well as mitochondrial superoxide. These findings suggest that AB5D may alleviate erythema by modulating inflammation via PGE2 and through antioxidation mechanisms.