The functional landscape of the skin microbiome is largely defined by dominant genera such as Cutibacterium and Staphylococcus, whereas rare commensals remain poorly understood. In this study, we identified Rothia kristinae BF00107, a skin-resident strain with a complete pantothenate biosynthesis pathway, as a novel postbiotic candidate with distinct dermatological benefits. BF00107 fermentation filtrate suppressed pro-inflammatory cytokines (IL-1β and TNF-α) in keratinocytes and restored extracellular matrix homeostasis in UVB-irradiated fibroblasts by upregulating COL1A1 expression and reducing MMP-1 levels. Consistent with the observed phenotypes, transcriptomic profiling revealed a strain-specific signature characterized by downregulation and upregulation of the expression of inflammatory mediators and barrier- and ECM-associated genes, respectively. Comparative genomics and metabolite profiling confirmed BF00107 as a unique high-pantothenate producer. Supplementation with pantothenic acid reproduced the anti-inflammatory and barrier-supporting effects of the strain, confirming its role as a key effector metabolite. Furthermore, BF00107 passed standard safety assessments, including the Human Repeat Insult Patch Test (HRIPT), Ames, and irritation tests, supporting its suitability for human applications. These findings establish the pantothenate-producing R. kristinae BF00107 as the first functionally validated Rothia strain with anti-inflammatory and photoaging-protective properties. This study expands the functional scope of the skin microbiome and highlights rare commensals as valuable reservoirs for safe, strain-specific postbiotic development.

Centella asiatica, a traditional herb, is widely recognized for its pharmacologically active components, such as asiaticoside, madecassoside, asiatic acid, and madecassic acid. These components render it a highly sought-after ingredient in various industries, including cosmetics and pharmaceuticals. This study aimed to enhance the production and activity of these pharmacological constituents of C. asiatica using the plant growth-promoting rhizobacterium Priestia megaterium HyangYak-01 during its cultivation. To achieve this goal, the researchers conducted field experiments, which revealed an increase in the production of pharmacologically active compounds in C. asiatica cultivated with a P. megaterium HyangYak-01 culture solution. Additionally, quadrupole time-of-flight mass spectrometry (Q-TOF MS) confirmed that the composition ratios of the C. asiatica extract treated with the P. megaterium HyangYak-01 culture solution differed from those of the untreated control and type strain-treated groups. Skin cell experiments indicated that the C. asiatica extract treated with the P. megaterium HyangYak-01 culture solution exhibited greater skin barrier improvement and less pronounced inflammatory responses than those from plants grown without the bacterial culture solution. This study demonstrates that microbial treatment during plant cultivation can beneficially influence the production of pharmacological constituents, suggesting a valuable approach toward enhancing the therapeutic properties of plants.

Injected botulinum neurotoxins (BoNT) reduce dynamic wrinkles by cleaving SNARE proteins at the neuromuscular junction; however, their large size mostly limits their use to injectable procedures. Certain polyphenols, including myricetin, have been shown in neuronal systems to reduce acetylcholine (ACh)-induced muscle contraction via inhibition of SNARE complex zippering, suggesting potential for topical use as modulators of skin cholinergic activity. This study aimed to identify a natural extract blend similarly capable of attenuating ACh release followed by characterization of the activity of this extract on human skin explants, alongside reference molecules BoNT/A, α-bungarotoxin, and myricetin. The natural extract blend (“Blend 1”) inhibited vesicle fusion and attenuated norepinephrine release in a cell culture system, inhibited muscle cell contraction within nerve/muscle co-culture, and attenuated ACh release consistent with myricetin and reference neurotoxins within human skin explants. Bulk transcriptomics of treated ex vivo skin explants revealed that BoNT/A, myricetin and Blend 1 all shared a similar downregulated inflammatory and anti-viral gene profile separate from α-bungarotoxin, but that myricetin and Blend 1 shared a large degree of overlap for upregulated genes associated with skin homeostasis and repair that was not observed for either toxin. These data support Blend 1 as a candidate for topical cosmetic use through modulation of BoNT/A-like cholinergic pathways, alongside activation of additional pathways associated with skin homeostasis and repair.

Injected botulinum neurotoxins (BoNT) reduce dynamic wrinkles by cleaving SNARE proteins at the neuromuscular junction; however, their large size mostly limits their use to injectable procedures. Certain polyphenols, including myricetin, have been shown in neuronal systems to reduce acetylcholine (ACh)-induced muscle contraction via inhibition of SNARE complex zippering, suggesting potential for topical use as modulators of skin cholinergic activity. This study aimed to identify a natural extract blend similarly capable of reducing ACh levels, followed by characterization of the activity of this extract on human skin explants, alongside reference molecules BoNT/A, α-bungarotoxin, and myricetin. The natural extract blend (“Blend 1”) inhibited vesicle fusion and attenuated norepinephrine release in a cell culture system, inhibited muscle cell contraction within nerve/muscle co-culture, and reduced ACh levels consistent with myricetin and reference neurotoxins within human skin explants. Bulk transcriptomics of treated ex vivo skin explants revealed that BoNT/A, myricetin, and Blend 1 all shared a similar downregulated inflammatory and antiviral gene profile separate from α-bungarotoxin, but that myricetin and Blend 1 shared a large degree of overlap for upregulated genes associated with skin homeostasis and repair that was not observed for either toxin. These data support Blend 1 as a candidate for topical cosmetic use through modulation of BoNT/A-like cholinergic pathways, alongside activation of additional pathways associated with skin homeostasis and repair.

Background: Previous studies have highlighted that marine organisms, such as microalgae and marine bacteria, exhibit significantly higher and more sustainable biosynthetic yields of unique carotenoids compared to terrestrial sources. These advantages in production efficiency have sparked significant interest in developing materials derived from marine origins. Marinophyll, natural carotenoids extracted from marine sources, have demonstrated potential in managing oxidative stress and inflammation linked to various skin conditions. Materials and Methods: HaCaT keratinocytes were treated with various concentrations of Marinophyll and hydrogen peroxide (H ₂ O ₂ ) to assess cell viability and intracellular ROS production. Antioxidant enzyme expression, including Nrf2, HO‐1, and SOD2, was evaluated using RT‐PCR and immunocytochemistry. The anti‐inflammatory effects of Marinophyll were investigated in HaCaT cells treated with IL‐4 and Poly I:C, and skin barrier repair was assessed in human skin explants using immunofluorescence staining. The skin explants were obtained from healthy adult donors (aged 43–57 years) undergoing elective breast reduction or abdominoplasty surgery, with informed consent and approval from the relevant ethics committee. All tissues were provided by Seoul National University Bundang Hospital. Results: The results showed that Marinophyll reduced intracellular ROS production in H ₂ O ₂ ‐exposed HaCaT cells. Additionally, Marinophyll significantly upregulated the mRNA and protein expression of Nrf2, HO‐1, and SOD2 in HaCaT cells. Pretreatment with Marinophyll reduced the levels of inflammatory cytokines IL‐1α and IL‐1β induced by IL‐4 and Poly I:C. In human skin explants, Marinophyll enhanced filaggrin expression, contributing to improved skin barrier function. Conclusion: Marinophyll demonstrates significant antioxidant, anti‐inflammatory, and skin barrier‐enhancing properties, making it a promising candidate for therapeutic applications in managing oxidative stress and inflammation‐associated skin disorders.