MARINA LEFORT¹*, KATINKA JUNG², FRANK PFLÜCKER¹, THOMAS HERRLING²

*Corresponding author

1. Merck, Frankfurter Str. 250, 64293 Darmstadt, Germany

2. Gematria Test Lab GmbH, Parkstraße 23, 13187 Berlin, Germany

Abstract

Skin is exposed on a daily basis to extrinsic factors that directly or indirectly cause the generation of free radicals in the living layers of this organ. Enzymatic and non-enzymatic antioxidants confer a protective defence system to skin. Cosmetic products are intended to protect and enhance this self-protection, even when exposed to environmental stressors for a prolonged time period. There is a need for highly efficient antioxidants that penetrate into the epidermal layers of the skin, and are resistant to environmental oxidative stress. Selected antioxidants should remain active for a lasting time period. In the present work, the effect of HDBM as a modern intelligent antioxidant compared to the well-known Tocopherol was assessed by means of Electron Spin Resonance Spectroscopy. Long term effects, photo-resistance, and stability were analysed. The results clearly show that only a stable antioxidant confers the required long lasting effect under realistic experimental conditions.

INTRODUCTION

The need for antioxidants in cosmetics has been recognized for many years.  Antioxidants comprise a large group of natural and synthetic ingredients that work to reduce free radical damage and environmental stress on skin. Antioxidants inhibit the oxidation of other molecules by removing free radicals intermediates and preventing the proliferation of reactive oxygen species (ROS). As ROS induce damage to skin lipids, proteins and nucleic acids, antioxidant protection is a key strategy to prevent accelerated skin aging. It is widely accepted that antioxidants substantially contribute to ward off some of the pollution-induced skin damages, as environmental hazards generate free radicals leading to increased oxidative reactions. In sunscreens, antioxidants help to reduce the radical load produced by sunlight and/or the UV filters themselves, offering a solution to prevent symptoms related to photo-aging. Therefore antioxidants are undeniably a must in every cosmetic product.
As a result of current antioxidant knowledge, an “antioxidant ingredient” can be found in about 50% of all products launched for skin care applications over ...