High-energy visible light at ambient doses and intensities induces oxidative stress of skin-Protective effects of the antioxidant and Nrf2 inducer Licochalcone A in vitro and in vivo

Photodermatol Photoimmunol Photomed. 2020 Mar;36(2):135-144. doi: 10.1111/phpp.12523. Epub 2019 Nov 17.


Background: Solar radiation causes skin damage through the generation of reactive oxygen species (ROS). While UV filters effectively reduce UV-induced ROS, they cannot prevent VIS-induced (400-760 nm) oxidative stress. Therefore, potent antioxidants are needed as additives to sunscreen products.

Methods: We investigated VIS-induced ROS formation and the photoprotective effects of the Nrf2 inducer Licochalcone A (LicA).

Results: Visible spectrum of 400-500 nm dose-dependently induced ROS in cultured human fibroblasts at doses equivalent to 1 hour of sunshine on a sunny summer day (150 J/cm2 ). A pretreatment for 24 hours with 1 µmol/L LicA reduced ROS formation to the level of unirradiated cells while UV filters alone were ineffective, even at SPF50+. In vivo, topical treatment with a LicA-containing SPF50 + formulation significantly prevented the depletion of intradermal carotenoids by VIS irradiation while SPF50 + control did not protect.

Conclusion: LicA may be a useful additive antioxidant for sunscreens.

Keywords: antioxidant; licochalcone A; reactive oxygen species; sunscreen; visible light.

MeSH terms

  • Antioxidants* / chemistry
  • Antioxidants* / pharmacology
  • Chalcones / chemistry
  • Dermis / metabolism*
  • Dermis / pathology
  • Fibroblasts / metabolism*
  • Fibroblasts / pathology
  • Glycyrrhiza / chemistry
  • Humans
  • NF-E2-Related Factor 2 / metabolism*
  • Oxidative Stress* / drug effects
  • Oxidative Stress* / radiation effects
  • Sunlight / adverse effects*
  • Sunscreening Agents* / chemistry
  • Sunscreening Agents* / pharmacology


  • Antioxidants
  • Chalcones
  • NF-E2-Related Factor 2
  • NFE2L2 protein, human
  • Sunscreening Agents
  • licochalcone A