Acetyl zingerone: An efficacious multifunctional ingredient for continued protection against ongoing DNA damage in melanocytes after sun exposure ends

• Published in: International journal of cosmetic science 2020-02, Vol.42 (1), p.36-45
• Main Authors: Chaudhuri, R.K., Meyer, T., Premi, S., Brash, D.
• Format: Article
• Language: English
• Subjects: Acetyl zingerone; Animals; antioxidant; Antioxidants; Cells, Cultured; Cyclobutane; Cyclobutane pyrimidine dimers; dark cyclobutane pyrimidine dimers (dark‐CPDs); Deoxyribonucleic acid; Dimers; DNA; DNA damage; DNA Damage - drug effects; Environmental Exposure; Exposure; Free radicals; Guaiacol - analogs & derivatives; Guaiacol - pharmacology; Incubation; Intracellular; Intracellular levels; Irradiation; Keratinocytes; Melanocytes; Melanocytes - drug effects; Melanocytes - radiation effects; Mice; Mice, Inbred C57BL; Molecular structure; Organic chemistry; Original; Pentane; Peroxynitrite; Prolongation; Pyrimidine Dimers - metabolism; quencher; Radiation; Reactive oxygen species; scavenger; Singlet oxygen; Sun screens; Sunlight - adverse effects; Sunscreens; Tocopherol; Ultraviolet radiation; ultraviolet radiation (UVR); Vitamin E; Zingerone
• ISSN: 0142-5463; 1468-2494
• DOI: 10.1111/ics.12582

Objective Recent research has shown that significant levels of cyclobutane pyrimidine dimers (CPDs) in DNA continue to form in melanocytes for several hours in the dark after exposure to ultraviolet radiation (UVR) ends. We document the utility of a new multifunctional ingredient, 3‐(4‐hydroxy, 3‐methoxybenzyl)‐pentane‐2,4‐dione (INCI acetyl zingerone (AZ)), to protect melanocytes against CPD formation after UVR exposure ends. Methods The use of AZ as an intervention to reduce CPD formation after irradiation was assessed in vitro by comparing kinetic profiles of CPD formation for several hours after irradiation in cells that were untreated or treated with AZ immediately after irradiation. Multifunctional performance of AZ as an antioxidant, quencher and scavenger was established using industry‐standard in vitro chemical assays, and then, its efficacy in a more biological assay was confirmed by its in vitro ability to reduce intracellular levels of reactive oxygen species (ROS) in keratinocytes exposed to UVA radiation. Molecular photostability was assessed in solution during exposure to solar‐simulated UVR and compared with the conventional antioxidant α‐tocopherol. Results Even when added immediately after irradiation, AZ significantly inhibited ongoing formation of CPDs in melanocytes after exposure to UVA. Incubation with AZ before irradiation decreased intracellular levels of UVA‐induced ROS formation in keratinocytes. Compared with α‐tocopherol, the molecular structure of AZ endows it with significantly better photostability and efficacy to neutralize free radicals (∙OH, ∙OOH), physically quench singlet oxygen (1O2) and scavenge peroxynitrite (ONOO−). Conclusion These results designate AZ as a new type of multifunctional ingredient with strong potential to extend photoprotection of traditional sunscreens and daily skincare products over the first few hours after sun exposure ends. Résumé Objectif Une étude récente a montré que des taux significatifs de dimères cyclobutyliques de pyrimidine (Cyclobutane Pyrimidine Dimers, CPD) dans l’ADN continuaient à se former dans les mélanocytes pendant plusieurs heures, dans l’obscurité, après que leur exposition aux radiations ultraviolettes (UV) ait pris fin. Nous documentons l’utilité d’un nouvel ingrédient multifonctionnel, le 3‐(4‐hydroxy, 3‐ méthoxybenzyle)‐pentane‐2,4‐dione (INCI acétyle zingérone (AZ)), pour protéger les mélanocytes contre la formation de CPD une fois l’exposition aux rayonnements UV termi