Unveiling a Novel in-vitro Model of Skin Inflamm-Aging: Validation of Terminalia chebula Extract and Supermolecular Bakuchiol for Reversal of Inflamm-Aging

Introduction: Sensitive skin is characterized by skin barrier disruption which is usually prone to react to external stimuli including UV, air pollution as well as cosmetic allergens. Sensitive skin tends to react with oxidative stress factors that could further lead to skin inflammation resulting in inflamm-aging. But almost no inflamm-aging models for sensitive skin, so it is worth constructing a method to screen anti-inflammaging ingredients and products. Methods: An in-vitro macrophages-fibroblasts model was established to evaluate the anti-inflammaging effect of ingredients. M1 phenotype and aging-associated gene expression were recorded by qPCR test to validate the inflamm-aging model. RNA sequencing was used to further elaborate the inflamm-aging mechanism of two validated ingredients. Results and conclusion: A novel in-vitro model of sensitive skin inflamm-aging was constructed by applying M1 phenotype of THP-1 culture medium supernatant to introduce the cellular senescence of the fibroblast cells, which could be used to screen out anti-inflammaging ingredients. In this model, supramolecular bakuchiol could promote collagen COL1A1 and COL3A3 production and inhibit inflammatory factors by increasing anti-inflammatory gene transcription (PTX3, ADAM33, and PDLIM1), while Terminalia chebula extract can inhibit cell senescence by reducing transcription of MAP4K2, and inflammatory factors CCL3 accumulation.