Background: Chronic exposure to ultraviolet B (UVB) causes a series of adverse skin reactions, such as erythema, sunburn, photoaging, and cancer, by altering signaling pathways related to inflammation, oxidative stress, and DNA damage. Marine algae have abundant amounts and varieties of bioactive compounds that possess antioxidant and anti-inflammatory properties. Thus, the objective of this study was to investigate the photoprotective effects of an ethanol extract of Sargassum thunbergii. Methods: Sargassum thunbergii phenolic-rich extract (STPE) was prepared, and its activity against UVB damage was evaluated using L929 fibroblast cells and zebrafish. STPE was extracted and purified by 40% ethanol and macroporous resin XDA-7. Reactive oxygen species (ROS) and antioxidant markers, such as superoxide dismutase (SOD), catalase (CAT) activities, and malondialdehyde (MDA) content were analyzed. The effect of STPE on UVB-induced inflammation was determined by inflammatory cytokine gene and protein expression. The expression of signaling molecules in the Nuclear Factor KappaB (NF-κB) pathway was determined by western blotting. DNA condensation was analyzed and visualized by Hoechst 33342 staining. In vivo evaluation was performed by tail fin area and ROS measurement using the zebrafish model. Results: The total polyphenol content of STPE was 72%. STPE reduced ROS content in L929 cells, improved SOD and CAT activities, and significantly reduced MDA content, thereby effectively alleviating UVB radiation-induced oxidative damage. STPE inhibited the mRNA and protein expression of TNF-α, IL-6, and IL-1α. STPE reversed DNA condensation at concentrations of 20 and 40 μg/mL compared with the UVB control. Moreover, STPE inhibited NF-κB signaling pathway activation and alleviated DNA agglutination in L929 cells after UVB irradiation. Additionally, 1.67 μg/mL STPE significantly increased the tail fin area in zebrafish, and 0.8–1.6 μg/mL STPE effectively eliminated excessive ROS after UVB radiation. Conclusions: STPE inhibited UVB-induced oxidative stress, inflammatory cytokine expression, and DNA condensation via the downregulation of the NF-κB signaling pathway, suggesting that it prevents UVB-induced photodamage, and has potential for clinical development for skin disease treatment.

Increasing life expectancy of the human population has created a demand for functional food with anti-skin aging properties. Skin aging is a degenerative process caused by oxidative stress, inflammation, and matrix destruction. Some secondary metabolites isolated from marine macroalgae have been shown to exhibit potential dermatological benefits. The present study investigated the skin-protective properties of the ethanolic extract from Sargassum thunbergii (STEE) via antioxidant, anti-inflammatory, and antiwrinkle effects on mouse fibroblast L929 cells. The optimal extraction conditions for STEE were determined as follows: ratio of liquid to solid 25:1mL/g, concentration of ethanol 40.2, and extraction time 40min. STEE was further purified by adsorption using a macroporous resin, SP700. STEE exhibited high DPPH radical and hydroxyl scavenging activity in vitro, enhanced the viability of H₂O₂-treated L929 cells, and reduced intracellular ROS generation in a dose-dependent manner. Superoxide dismutase and glutathione peroxidase activities and total antioxidant capacity in H₂O₂-treated L929 cells were increased while malondialdehyde content was markedly reduced by pretreatment with STEE. The inhibitory effect of STEE on H₂O₂-induced inflammation was shown by the downregulation of tumor necrosis factor-α, interleukin-6, cyclooxygenase-2, and inducible nitric oxide synthase. Furthermore, STEE reduced the matrix metalloproteinase-2 expression and inhibited collagenase and elastase activities. Moreover, STEE was nonirritating to human skin at 100mg/mL according to the in vitro skin irritation test using EpiSkin. Hemolysis assay showed that the hemolysis EC50 (1275μg/mL) of STEE is much higher than the maximum effective concentration (125μg/mL) against H₂O₂ exposure. Our results demonstrate that STEE may be a good candidate for the development of anti-skin aging functional food and cosmetic products.

As a culturally iconic Chinese delicacy, pufferfish lacks systematic research on thermal processing optimization and pre-cooked meal development, limiting its industrial standardization and quality preservation. This study aimed to bridge this gap by evaluating steaming effects on Takifugu flavidus quality. This study systematically evaluated its physicochemical properties and flavor profiles under different steaming durations by determining the water loss rate, mass loss rate, water distribution status, textural properties, color, and free amino acid content using an electronic nose, electronic tongue, and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS). The results indicated that the core temperature of the fish meat reached 70 °C after 9 min of steaming. With higher steaming time, its mass loss rate and water loss rate generally increased, though the water loss rate temporarily decreased at 10 min. The mass loss rate stabilized after 12.5 min. The hardness and chewiness of the fish meat increased significantly when steamed for 12.5 min or longer. After 5 min of steaming, the brightness value and yellow-blue value of the fish meat significantly increased, whereas the red-green value significantly decreased. The total free amino acid content showed a fluctuating upward trend and electronic tongue analysis revealed an increase in umami and richness after steaming. Electronic nose and HS-GC-IMS analyses demonstrated that the variety and content of volatile flavor compounds significantly increased with prolonged steaming. Sensory evaluation showed that the 10 min steaming group exhibited better texture and color, while the 15 min steaming group had the best odor. Therefore, the optimal steaming time for T. flavidus was determined to be 10–15 min. For home cooking, a 15 min steaming process achieves the peak abundance of flavor compounds and the highest sensory evaluation score. For the industrial production of pre-cooked meals, a 10 min steaming process can meet the doneness requirements while maintaining suitable textural properties and color stability. The findings of this study not only advance the scientific understanding of thermal processing effects on pufferfish quality attributes, but also establish a critical technological foundation for developing standardized industrial processing protocols and high-quality pre-prepared pufferfish products.

To effectively shorten the rehydration time of Apostichopus japonicus and reduce the nutrient loss during the rehydration process, an ultrasound-assisted rehydration method was adopted to rehydrate semi-dry salted A. japonicus in this study. The effects of different ultrasonic powers, temperatures, and times on the rehydration characteristics, textural characteristics, and sensory quality of the semi-dry salted A. japonicus were studied. Box–Behnken response surface analysis was used to study the influence of the interactions among the three factors on the rehydration ratio of the semi-dry salted A. japonicus, and a quadratic multinomic regression model was established to predict the optimal rehydration ratio. The results showed that ultrasound could change the structure of semi-dry salted A. japonicus and form a spatial network structure, thereby improving its water absorption capacity and reducing rehydration time. The optimal rehydration effect could be obtained when the ultrasonic power was 400 W, the ultrasonic temperature was 50 °C, and the ultrasonic time was 83 min. Ultrasonic power, ultrasonic time, and ultrasonic temperature influenced the rehydration ratio of the semi-dry salted A. japonicus. Under the optimal rehydration conditions in this study, the rehydration ratio of semi-dry salted A. japonicus obtained by the test was 2.103, which was consistent with the value predicted by the Box–Behnken response surface method.

Fish-derived collagens represent highly promising alternatives to terrestrial matrices for advanced biomedical applications, yet how species-driven evolutionary divergence modulates their underlying supramolecular architectures and functional phenotypes remains poorly understood. Here, we systematically isolate and structurally map acid-soluble Type I collagens from four geographically and phylogenetically distinct teleost swim bladders: China large yellow croaker, New Zealand large yellow croaker, basa fish, and silver carp. Electrophoretic profiling confirmed the preservation of intact Type I collagen frameworks characterized by prominent α1 and α2 chains. The results show that the China large yellow croaker achieves a maximum yield of 23.0%, surpassing the lowest-yielding New Zealand matrix at 14.2% by a 62.0% relative margin. This China yellow croaker matrix exhibits superior primary structural preservation, featuring a peak glycine content of 20.48% and high triple-helical stability. Crucially, macro-thermal resilience tracks evolutionary climate adaptations. Tropical freshwater basa fish displays the highest denaturation temperature of 47.12 °C to establish a 10.63 °C thermal gap over cold-water New Zealand yellow croaker, whereas colloidal dispersion peaks in silver carp via a high ζ-potential of 32.3 mV and a minimum supramolecular aggregate diameter of 465.2 nm. Furthermore, scanning electron microscopy revealed distinct interspecific variations in sponge microstructures, where the New Zealand yellow croaker collagen displayed a relatively open, interconnected porous network. Coupled with localized triple-helical structural relaxation, this matrix achieved a peak hydroxyl radical scavenging efficacy of 53.2% at a concentration of 5 mg/mL. These findings provide a molecular blueprint for rational selection and engineering of source-specific fish-derived collagens as advanced biomaterials.