The effect of Salix alba L. bark extract on dark circles in vitro and in vivo

Abstract Objective Dark circles in the infraorbital area are a common cosmetic concern among individuals because they exhibit fatigue and are undesirable across all ages. Of the dark circle etiologies, blood stasis by poor‐vascular integrity can cause darkening of the lower eyelid skin, which might be alleviated by reduced endothelial permeability. In this study, we investigated the effects of Salix alba bark extract (SABE) on the synthesis of hyaluronic acid (HA) in fibroblasts and vascular integrity protection from inflammatory cytokine. We also performed a clinical trial investigating the effect of SABE on dark circles. Methods To confirm the effect of SABE on HA synthesis in human dermal fibroblasts (HDFs), we performed ELISA and real‐time PCR. We investigated the interaction HDF‐secreted substance with vascular integrity, and human dermal microvascular endothelial cells (HMEC‐1) were treated with conditioned medium (CM) from HDF treated with or without SABE. Subsequently, we conducted a clinical study on 29 subjects by having them apply SABE containing cream for 8 weeks. Results Salix alba bark extract treatment increased HA synthesis and regulated HMW–HA‐related gene expressions in HDF. CM from SABE‐treated HDF alleviated endothelial permeability and led to improved vascular integrity in HMEC‐1 cells. Treatment with the cream containing 2% SABE for 8 weeks improved the parameters measuring dark circles, skin microcirculation and elasticity. Conclusion Our results showed that SABE could protect against dark circles in vitro, and that topical treatment of SABE improved the clinical indexes of dark circles in a clinical study. Therefore, SABE can be used as an active ingredient for improving dark circles.