β‐Ionone attenuates dexamethasone‐induced suppression of collagen and hyaluronic acid synthesis in human dermal fibroblasts

Stress is a major contributing factor of skin aging, which is clinically characterized by wrinkles, loss of elasticity, and dryness. In particular, glucocorticoids are generally considered key hormones for promoting stress‐induced skin aging through binding to glucocorticoid receptors (GRs). In this work, we aimed to investigate whether β‐ionone (a compound occurring in various foods such as carrots and almonds) attenuates dexamethasone‐induced suppression of collagen and hyaluronic acid synthesis in human dermal fibroblasts, and to explore the mechanisms involved. We found that β‐ionone promoted collagen production dose‐dependently and increased mRNA expression levels, including collagen type I α 1 chain (COL1A1) and COL1A2 in dexamethasone-treated human dermal fibroblasts. It also raised hyaluronic acid synthase mRNA expression and hyaluronic acid levels. Notably, β‐ionone inhibited cortisol binding to GR, subsequent dexame-thasone‐induced GR signaling, and the expression of several GR target genes. Our results reveal the strong potential of β‐ionone for preventing stress‐induced skin aging and suggest that its effects are related to the inhibition of GR signaling in human dermal fibroblasts.