Skin-Related Effects of Corynebacterium amycolatum SB-1 Ferment Filtrate and Functional Characterization of Ellagic Acid

Previous research has established a link between the genus Corynebacterium in the skin microbiota and skin health; however, studies investigating the specific effects of Corynebacterium-derived substances on skin cells remain limited. In this study, we isolated eight strains of Corynebacterium from the facial skin of female participant. To investigate the potential skin improvement effects of these isolates, three cultured skin cell lines (Hs68, HaCaT, and B16-F10) were treated with the supernatants of each strain. We then evaluated and compared the gene expression levels (ELN, COL1A1, IL-1{beta}, and HAS3) alongside their inhibitory effects on melanin biosynthesis. Corynebacterium amycolatum SB-1 was selected as the final candidate for subsequent analysis, primarily based on its rapid growth rate and high cell yield. Using LC-TOF/MS, we screened the postbiotic candidates from the SB-1 strain and identified ellagic acid as a known polyphenolic antioxidant with potent anti-melanogenic effects beneficial for skin improvement. To validate the effects of ellagic acid on skin cells, we assessed FLG gene expression and its inhibition of melanin biosynthesis. Additionally, RNA sequencing was performed to elucidate the underlying molecular mechanisms, revealing that ellagic acid is significantly involved in inhibiting melanogenesis and promoting collagen synthesis. Taken together, our results highlight ellagic acid derived from strain SB-1 as a highly effective bioactive compound for improving skin health, specifically targeting hyperpigmentation and skin aging.