In the present study, we investigated the anti-inflammatory and anti-melanogenic effects of Leuconostoc mesenteroides subsp. DB-21-derived exosomes (DB-21 exosomes), isolated from Camellia japonica flower in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells and melanocyte-stimulating hormone (α-MSH)-induced B16F10 melanoma cells. We confirmed that DB-21 exosomes were not toxic to LPS-induced RAW 264.7 macrophage cells and α-MSH-induced B16F10 melanoma cells. Moreover, we confirmed that DB-21 exosomes inhibit the pro-inflammatory cytokines IL-6, IL-1β, TNF-α, PGE₂, and the expression of inflammatory factors iNOS and COX-2. We also found that DB-21 exosomes have a concentration-dependent ability to inhibit melanin, TRP-1, TRP-2, tyrosinase, and MITF, which are factors involved in melanogenesis. Additionally, it inhibits the phosphorylation of Akt and GSK-3β, and MAP kinase pathway proteins such as ERK, JNK, and p38. We confirmed that DB-21 exosomes inhibit melanin synthesis in B16F10 cells through various pathways, and based on previous results, they may be used as a functional cosmetic material with anti-inflammatory and anti-melanogenic activities.

Among the microorganisms present in the microbiome of Camellia japonica flowers, extracellular vesicles (EVs) derived from Leuconostoc mesenteroides were isolated to investigate their modulatory effects on moisturizing and barrier-related molecular markers. To identify the function of major proteins in L. mesenteroides DB-21-derived extracellular vesicles (LEVs), Gene Ontology (GO) analysis was performed, revealing ATP binding, ribosomal structural proteins, and metal ion binding as predominant molecular-function categories. These proteomic characteristics provide a molecular context that supports the interpretation of the moisturizing and barrier-related responses observed in this study. To further verify new findings, we performed functional evaluations using in vitro and 3D skin models. LEVs increased the mRNA expression level of HAS3, which encodes hyaluronic acid synthase. In addition, the expression levels of filaggrin and involucrin, key proteins involved in skin barrier formation, increased, and these markers were determined a concentration-dependent increase in a 3D artificial skin model. Also, we confirmed that the expression levels of filaggrin and involucrin, which were reduced by UVB damage, were restored when LEVs were applied. In conclusion, LEVs are effective in enhancing various molecular markers related to the skin barrier function, and these results reveal that they hold promise as next-generation microbiome-based functional ingredients.

Purpose: In this study, we investigated the biological activities of Diphylleia grayi extract as a natural cosmetic ingredient. Methods: The antioxidant activities of Diphylleia grayi extract was measured through 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazinyl (DPPH), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) scavenging assay and Fluorescence recovery after photobleaching (FRAP) assay. We further investigated whether Diphylleia grayi extract could reduce the intracellular reactive oxygen species (ROS) using dichlorofluorescin diacetate (DCF-DA) fluorescence. To investigate the whitening effect, we conducted tyrosinase inhibition assay and L-DOPA oxidation inhibition assay. Furthermore, we performed collagenase inhibition assay to evaluate the anti-wrinkle activity of Diphylleia grayi extract. Results: Diphylleia grayi extract showed strong antioxidant activities on DPPH, ABTS radical scavenging assay. Furthermore, Diphylleia grayi extract decreased the intracellular ROS on skin normal cells. Diphylleia grayi extract has also inhibition activities of tyrosinase, L-DOPA oxidation and collagenase. Conclusion: Therefore, Diphylleia grayi extract was identified as a promising natural cosmetic ingredient which has antioxidant, whitening and anti-wrinkle properties.