Conflicts of interest: None declared.
Topical isoflavones provide effective photoprotection to skin
Article first published online: 18 MAR 2008
© 2008 The Authors
Photodermatology, Photoimmunology & Photomedicine
Volume 24, Issue 2, pages 61–66, April 2008
How to Cite
Lin, J.-Y., Tournas, J. A., Burch, J. A., Monteiro-Riviere, N. A. and Zielinski, J. (2008), Topical isoflavones provide effective photoprotection to skin. Photodermatology, Photoimmunology & Photomedicine, 24: 61–66. doi: 10.1111/j.1600-0781.2008.00329.x
- Issue published online: 18 MAR 2008
- Article first published online: 18 MAR 2008
- Accepted for publication:10 September 2007
Background/purpose: Isoflavones, one main group of phytoestrogens, have antioxidative and photoprotective effects in cellular and mouse studies. The aim of this study is to obtain a more comprehensive understanding of the isoflavone-mediated photoprotection with the pig skin model, a more human-resembling model.
Methods: The pig skin was treated with five well-known isoflavone compounds (genistein, equol, daidzein, biochanin A, and formononetin) and one antioxidant combination solution of 15% vitamin C and 1% vitamin E and 0.5% ferulic acid (CEF) daily for 4 days. Skin was irradiated with solar-simulated UV irradiation, 1 to 5 minimal erythema dose (MED) at 1-MED intervals. Evaluation was carried out 24 h later by colorimeter-measured erythema and sunburn cell numbers.
Results: Topical application of 0.5% solutions of three individual phytoestrogens – genistein, daidzein, biochanin A – are better than similar solutions of equol or formononetin in protecting pig skin from solar-simulated ultraviolet (SSUV)-induced photodamage, as measured by sunburn cell formation and/or erythema. However, the protection was less than that provided by a topical combination antioxidant standard containing 15% L-ascorbic acid, 1%α-tocopherol, and 0.5% ferulic acid.
Conclusion: Isoflavones provide effective photoprotection and are good candidate ingredients for protection against ultraviolet (UV) photodamage.