Evaluation of Antioxidants’ Ability to Enhance Hyaluronic Acid-Based Topical Moisturizers

Introduction: Hyaluronic acid (HA) is a unique molecule with multiple biological activities. In skin, HA plays an essential role as a humectant, capable of binding up to 1000 times its mass with water, leading to both skin moisturization and extracellular matrix rigidity. HA concentration and synthesis decreases significantly in aging skin, due to exogenous and endogenous factors, including photoaging and HA metabolism, respectively. A key driver for HA degradation and decrease in concentration is mediated via the induction of reactive oxygen species (ROS) and other free radicals. In this study, we evaluate antioxidant ingredients essential in the development of next-generation multi-weight HA-based topical formulations aimed at leveraging hyaluronic acid’s ability to maximize anti-aging properties. Methods: Two antioxidants, glycine saponin and glycyrrhetinic acid, were evaluated for stimulation of endogenous HA production and inhibition of endogenous hyaluronidase activity in an in vitro and cell-free assay. Results: The antioxidant glycine saponin induced endogenous HA synthesis in keratinocytes, while the antioxidant glycyrrhetinic acid demonstrated an approximately 54% reduction of hyaluronidase activity for the HA-degrading enzyme HYAL1. Conclusion: This study demonstrates the ability of two antioxidants (glycine saponin and glycyrrhetinic acid, essential in the development of the next generation of multi-weight HA plus antioxidant complex-based topical skin formulations) to limit the signs of aging skin, addressing limitations of many currently available topical HA-based formulations.