Antimelanogenic effect of fermented licorice water extract on murine melanoma B16F10 cells

This study investigated the skin-whitening effect of fermented licorice water extract (FLWE) on B16F10 melanocytes. Bioconversion mediated by Issatchenkia orientalis MFST-based fermentation altered licorice's bioactive components. FLWE significantly increased polyphenol and flavonoid content compared with non-fermented licorice water extract (LWE). FLWE more effectively inhibited melanocyte-stimulating hormone-induced melanin production and tyrosinase activity than LWE. RT-PCR and Western blotting revealed that FLWE inhibits the expression of microphthalmia-associated transcription factor (MITF), the transcription factor for TRP-1, TRP-2, and tyrosinase. On analyzing FLWE's inhibitory activity against preexisting tyrosinase within melanocytes, FLWE did not directly inhibit tyrosinase itself, suggesting that FLWE exerts its whitening effect by inhibiting MITF activation. TLC and HPLC indicated that FLWE's superior whitening effect emanates from increased levels of aglycone compounds (isoliquiritigenin, glycyrrhizic acid, licochalcone A, and glabridin) after licorice fermentation. Overall, FLWE is a potentially effective skin-whitening material without side effects (vitiligo) commonly associated with direct tyrosinase inhibition.

The online version contains supplementary material available at 10.1007/s10068-025-01878-z.