A Glabridin-enriched Licorice Extract Demonstrates Multifunction Skin Benefits In Vitro

OBJECTIVE: Pigmentary disorders (freckles, melasma, and post-inflammatory hyper-pigmentation) are common in Asian Skin Types III-V occurring as a consequence of ultraviolet (UV) insult, oxidative stress, pollution, and changes in hormonal levels. With the increasing demand for natural and safe ingredients in cosmetics to treat pigmentary disorders, phytocompounds are gaining attention. One such phytoactive is glabridin, obtained from the popular plant Glycyrrhiza glabra (licorice). In the present study, Glyci- Bright®, a stable and standardized, 5% glabridin-enriched extract, was developed and tested for in vitro antioxidative, UV protection, SPF, and melanin reduction activity. METHODS: Glabridin-enriched licorice root extract (GlyciBright®) was prepared by a multistep process and glabridin content was quantified using HPLC. GlyciBright® was evaluated for skin care activities viz., antioxidant activity by ABTS, theoretical Sun Protection Factor (SPF) by measuring UV-B (290-320nm) absorbance using UV-Vis spectrophotometer, tyrosinase inhibition, melanin reduction in mice melanoma cells (B16F10), and photoprotection on human dermal fibroblasts (HDF), RESULTS: GlyciBright® showed ABTS scavenging activity with an IC50 value of 51μg/ml. The IC50 for tyrosinase inhibition was observed at 20μg/ml and a 41% reduction in melanin was found at 15μg/ml in the B16F10 cell line. GlyciBright® showed no toxicity effects up to 100μg/ml (IC50), reversed the cytotoxic effect of UV-B on HDF, and demonstrated a theoretical SPF of 37 at 250μg/ml. CONCLUSION: GlyciBright® shows prominent antioxidant, UV-B protective, and skin-brightening activity attributed to the active ingredient glabridin. Based on these activities, it is postulated to offer protection against hyperpigmentation and UV-induced skin damage implicated in pigmentary disorders.