The red alga Kappaphycus alvarezii is a rich source of polysaccharides, but their high molecular weight limits skin permeability and bioavailability. To address this, we employed a free-radical degradation method to produce a low-molecular-weight polysaccharide, KP-90. Evaluation in UVB-irradiated HaCaT cells and UVA-irradiated human dermal fibroblasts demonstrated that KP-90 significantly enhanced cell viability and mitigated oxidative stress by suppressing reactive oxygen species and malondialdehyde, while restoring antioxidant enzymes (SOD, CAT and GSH-Px). Furthermore, KP-90 downregulated matrix metalloproteinases (MMP-1, -3, -9) and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), thereby reducing extracellular matrix degradation and inflammation. These in vitro findings were corroborated in a UVB/UVA-irradiated nude mice model, where KP-90 alleviated epidermal hyperplasia, increased collagen I and hyaluronic acid synthesis, and improved visible signs such as wrinkles and skin laxity. These findings identify KP-90 against skin photoaging and provide a strategic approach for valorization underexploited marine biomass.

Coreopsis tinctoria Nutt. is an important medicinal plant in traditional Uyghur medicine. The skin-lightening potential of the flower has been recognized recently; however, the active compounds responsible for that are not clear. In this work, tyrosinase, a target protein for regulating melanin synthesis, was immobilized on the Whatman paper for the first time to screen skin-lightening compounds present in the flower. Quercetagetin-7-O-glucoside (1), marein (2), and okanin (3) were found to be the enzyme inhibitors. The IC₅₀ values of quercetagetin-7-O-glucoside (1) and okanin (3) were 79.06 ± 1.08 μM and 30.25 ± 1.11 μM, respectively, which is smaller than 100.21 ± 0.11 μM of the positive control kojic acid. Enzyme kinetic analysis and molecular docking were carried out to investigate their inhibition mechanism. Although marein (2) showed a weak inhibition effect in vitro, it inhibited the intracellular tyrosinase activity and diminished melanin production in melanoma B16 cells as did the other two inhibitors. The paper-based ligand fishing method developed in this work makes it effective to quickly screen tyrosinase inhibitors from natural products. This is the first report on the tyrosinase inhibitory effect of those three compounds, showing the promising potential of Coreopsis tinctoria for the development of herbal skin-lightening products.

Skin photoageing remains a topic of considerable concern. Retinol (RT) and retinyl palmitate (RP) have shown preliminary therapeutic efficacy; nevertheless, the high irritation associated with RT and the relatively modest efficacy of RP have constrained their broader application. Consequently, this study explored the effects and biosafety of RT and RP in repairing UV-induced skin ageing through a series of in vitro cell experiments, in vitro hemolysis assays, UV-irradiated mouse models, and molecular simulation techniques. The findings revealed that the interaction between RT and RP achieved complementary and enhanced therapeutic outcomes. Specifically, this combination improved the biosafety profile of retinoid formulations, accelerated cell migration rates, and facilitated the activation of the peroxisome proliferator-activated receptor α (PPARα) pathway. Moreover, the action of RT and RP further mitigated epidermal hyperplasia, mast cell infiltration, and the expression levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumour necrosis factor-α (TNF-α), while stimulating the synthesis of type I collagen. Metabolomics and transcriptomics analyses indicated that RT and RP exerted complementary effects through metabolic pathways, significantly elevating the overall therapeutic efficacy. Network pharmacology and molecular docking studies unveiled that the structural similarity between RT and RP was one of the contributors to their enhancement. In conclusion, this study demonstrated that the combined application of RT and RP exhibited marked effects. Through their mutual action, they not only potentiated each other’s therapeutic effects but also achieved complementary and optimised therapeutic outcomes, thereby substantially enhancing the overall efficacy.

Fibronectin (FN) is a key mechanoresponsive glycoprotein within the extracellular matrix (ECM) that contributes to the assembly of a dynamic fibrillar network that is important for maintaining tissue structure and mediating cellular signaling. In this review, we delineate the molecular mechanisms underlying FN’s role in barrier restoration, ECM remodeling, and stem cell niche regulation, functions that inform its applications in both regenerative medicine and cosmetic science. In biomedical contexts, FN is recognized as a valuable biomarker for numerous diseases, a promising therapeutic target, and a functional component of biomedical material matrices. FN is involved throughout the skin repair process, making it a physiologically active ingredient for cosmetic anti-aging treatments, alleviating sensitive skin conditions, and enhancing cutaneous immunity. This review also addresses significant translational challenges associated with FN research, including recombinant protein production and rational peptide design, and suggests avenues for future work. Ultimately, studies on FN highlight the complexity of ECM biology and lay the groundwork for innovative approaches to advancing human health and developing new cosmetic treatments.

Background: Retinol, an important bioactive substance with multiple physiological functions such as promoting collagen synthesis, inhibiting matrix metalloproteinase activity, alleviating oxidative stress, regulating gene expression, and promoting epidermal cell proliferation, has a significant effect on skin damage recovery. Hydroxyasiaticoside, a triterpenoid saponin derived from Centella asiatica (L.) Urb., is closely related to the secretion of collagen types I and III, and possesses multiple biological activities, including moisturizing, antioxidants, anti-apoptosis, neuroprotection, anti-inflammation, and the promotion of wound healing. It plays a particularly prominent role in reducing oxidative stress in wounds and inducing vasodilatation. Objective: The aim of this study was to investigate the therapeutic efficacy of retinol combined with hydroxyasiaticoside in histamine-induced atopic dermatitis. Materials and Methods: The experiment was carried out using three different concentrations of a retinol and hydroxyasiaticoside mixed solution: low, medium, and high concentrations. After inducing atopic dermatitis in mice through histamine administration, these solutions were applied to the skin surface of the mice, and a comparative analysis was conducted with both the control group and the model group. The effect of combination therapy on atopic dermatitis was evaluated through histopathology, immunohistochemistry, and transcriptomic analysis. Results: The combination of retinol and hydroxyasiaticoside significantly attenuated histamine-induced scratching behaviors, alleviated the phenomenon of epidermal hyperplasia, and effectively reduced the proliferation, infiltration, and degranulation of mast cells. In addition, the combination inhibited the expression of relevant pro-inflammatory cytokines. Quantitative RNA-seq analysis revealed that the gene expression patterns were similar in different concentration groups. However, the medium dose group may be able to regulate skin inflammation by regulating upstream genes to inhibit autophagy-related pathways. Further GO analysis revealed that the low-dose group mainly affected metabolism-related genes, the medium-dose group affected more genes related to body systems, and the high-dose group was dominated by genes related to human diseases.