Skin-soothing Effects of Oenothera biennis Flower Extract

Purpose: The current study aimed to assess the use of Oenothera biennis flower extract (OBFE) as a cosmetic ingredient exhibiting potential skin-soothing and anti-inflammatory activities.Methods: O. biennis flowers were extracted with 70% ethanol and used in experiments to confirm skin-soothing efficacy. Several criteria related to skin soothing, such as antioxidant activity, barrier enhancement, moisturization, and sebum secretion control, and anti-inflammatory effects, were evaluated. Antioxidant activity was determined via the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test. Skin barrier enhancement was assessed by studying the mRNA expression of filaggrin (FLG), a key skin barrier component, through quantitative real-time PCR. Moisturizing efficacy was evaluated by analyzing hyaluronic acid (HA) expression through ELISA. Furthermore, the expression levels of the inflammatory agents nitric oxide (NO) and prostaglandin E₂ (PGE₂) were investigated in addition to checking the inhibitory effect on sebum production to confirm the anti-inflammatory effects.Results: Antioxidant activity was confirmed by DPPH radical scavenging ability, and OBFE demonstrated efficacy equivalent to that of L-ascorbic acid, positive control. Furthermore, OBFE recovered the Staphylococcus aureus-induced downregulation of FLG expression. Moreover, OBFE significantly improved the production of HA, surpassing the beneficial effect of the positive control, retinoic acid. OBFE also exhibited significant reduction in LPS-induced production of NO and PGE₂ and effectively inhibited palmitic acid-induced sebum production in sebocytes.Conclusion: These findings imply that OBFE is a potential cosmetic ingredient that can be used to soothe sensitive skin as it exhibits antioxidant, skin barrier strengthening, moisturizing, anti-inflammatory, and sebum-control effects.