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.