Evaluation of Antioxidants' Ability to Enhance Hyaluronic-acid Based Topical Moisturizers.

ABSTRACT

Background: Hyaluronic acid (HA) is a unique molecule of the extracellular matrix with multiple biological activities. In skin, HA plays an essential role as a humectant, capable of binding up to 1,000 times its mass with water, providing skin with moisture and viscoelastic properties. HA concentration and synthesis decrease significantly in aging skin, due to exogenous and endogenous factors, including photoaging and HA metabolism. A key driver for HA degradation and reduced concentration is mediated via induction of reactive oxygen species (ROS) and other free radicals. Objective: In this study, we evaluate antioxidant ingredients essential in the development of next-generation HA-based topical formulations aimed at leveraging HA's ability to maximize anti-aging properties. Methods: Two antioxidants, glycine saponin (Glycine soja germ extract) and glycyrrhetinic acid (enoxolone), were evaluated for stimulation of endogenous HA production and inhibition of endogenous hyaluronidase activity, respectively. Results: The antioxidant glycine saponin induced endogenous HA synthesis in fibroblasts, while the antioxidant glycyrrhetinic acid decreased the degradation rate of HA by 54 percent. Conclusion: While HA has been included in numerous topical skin products, critical aspects of HA metabolism, especially in aging skin, have often been overlooked, including decreases in HA synthesis with increasing age, and increases in HA degradation mediated by exogenously induced reactive oxygen species and free radicals and increased enzymatic degradation by endogenous hyaluronidases. Here, we describe a unique approach to inclusion of two antioxidants essential for the development of the next generation of antioxidant complex-based topical skin formulations to limit the signs of aging skin.