Melanogenesis, essential for skin photoprotection and pigmentation, can lead to disorders like melasma and hyperpigmentation, which are challenging to treat and affect quality of life. Docosatrienoic acid (DTA), a polyunsaturated omega-3 fatty acid, has been identified as a potential regulator of skin aging. This study investigates DTA’s effects on melanogenesis and its underlying molecular mechanisms using in silico and in vitro analyses. SwissSimilarity analysis revealed that DTA shares close structural similarities with known anti-melanogenic lipids, suggesting it may inhibit melanogenesis in similar manners. Our results demonstrated that DTA reduces melanin content and intracellular tyrosinase activity in B16F10 cells, significantly downregulating the mRNA expression of tyrosinase, TRP-1, and TRP-2 by inhibiting MITF translocation to the nucleus. While DTA exhibited mild inhibitory effects on mushroom tyrosinase activity and antioxidant properties at higher concentrations, direct inhibition of tyrosinase is likely not the primary mechanism, as the observed anti-melanogenic effects occurred at much lower concentrations compared to those required for direct tyrosinase inhibition. Together, DTA-mediated modulation of MITF and tyrosinase mRNA expression offers a novel approach to treating hyperpigmentation. DTA’s potential extends into the cosmetic industry, enhancing product stability, functionality, and aesthetics. Further research is needed to explore DTA’s broader applications in skincare and cosmetic formulations.

Melanogenesis, the biological process responsible for melanin synthesis, plays a crucial role in determining skin and hair color, photoprotection, and serving as a biomarker in various diseases. While various factors regulate melanogenesis, the role of fatty acids in this process remains underexplored. This study investigated the anti-melanogenic properties of 10(E)-pentadecenoic acid (10E-PDA) through both in silico and in vitro analyses. SwissSimilarity was utilized to predict the functional properties of 10E-PDA by comparing it with structurally similar lipids known to exhibit anti-melanogenic effects. Subsequent in vitro experiments demonstrated that 10E-PDA significantly reduced melanin production and intracellular tyrosinase activity in α-MSH (melanocyte-stimulating hormone)-stimulated B16F10 melanoma cells without exhibiting significant cytotoxicity at concentrations up to 15 μM. Further mechanistic studies revealed that 10E-PDA inhibited the nuclear translocation of microphthalmia-associated transcription factor (MITF), consistent with the decrease observed in p-MITF protein levels. It also decreased the mRNA levels of tyrosinase-related proteins (TRP-1, TRP-2) and tyrosinase, while reducing the protein levels of TRP-1 and tyrosinase, but not TRP-2. These findings suggest that 10E-PDA exerts its anti-melanogenic effects by modulating the MITF/tyrosinase axis, presenting potential therapeutic implications for skin pigmentation disorders.

Efficient detection methods must be developed for 1,4-dioxane due to its suspected status as a human carcinogen, which is highly mobile in food and environmental resources. In this regard, this experiment has been conducted to develop reliable and selective detection and measurement methods by using static headspace (SH) isolation, followed by gas chromatography–mass spectrometry (GC-MS). A new method was developed for determining the spiked 1,4-dioxane contents in a polyethylene glycol 600 (PEG 600). The optimal condition for SH-GC-MS was discussed. The representative ions of 1,4-dioxane and 1,4-dioxane-d8 in the SIM mode of MS are 88 and 96, respectively, and the peaks of the SIM mode were separated and confirmed. The linear range for the method covers 0.25 to 100 mg/L with a coefficient of determination (R²) ≥ 0.999. The method applicability was demonstrated by spike recovery across a variety of food additives (i.e., chlorine bitartrate, choline chloride, polysorbate 20 and 60, and PEG 1000). All spike recovery from the tested samples was in the range of 89.50–102.68% with a precision of 0.44–11.22%. These findings suggest a new analytical method for food safety inspection, and could be applicable for ensuring the safety of foods and environmental and public health on a broad scale.

The release of 1,4-dioxane probably contributes to the deterioration of marine habitats, animal health, and human liver and kidneys. The formulation of 1,4-dioxane in glycols, which has been applied for dehumidifying agents in refineries, may need to be replaced to ensure public health. Further, it is necessary to identify and precisely determine the levels of 1,4-dioxane in glycols for food quality control and environmental safety regulation. The objectives of this study were to validate a liquid–liquid extraction (LLE) method for 1,4-dioxane analysis and to optimize the LLE conditions using a response surface methodology (RSM). With consideration of the food matrix and its applications, polyethylene glycol 200 was used as the model system and analyzed by gas chromatography with flame ionization detection. In the experiments for the optimum extraction temperature and time of 1,4-dioxane in ultrasonic treatment, they were 20 °C and 10 min, respectively. The experimental conditions and results were analyzed by RSM with the Box–Behnken design, and the optimal extraction conditions for the LLE were determined to be coded with three independent variables (sample weight, solvent volume, and centrifugation speed). The amount of 1,4-dioxane increased as the amount of sample increased, whereas the amount of 1,4-dioxane decreased as the amount of solvent increased. This information can help to find the analytical methods for regulating the 1,4-dioxane content and its precise quantification in food products.

Sargassum serratifolium (S. serratifolium), listed in the Food Code, is known for its antioxidant and anti-inflammatory properties and is used in cosmetic applications. However, due to limited industrial utilization and overaccumulation in marine environments, Sargassum has been designated as a marine pollutant by the UN Environment Agency. To improve resource efficiency and reduce environmental burden, this study developed a dual-extraction strategy to isolate extracellular vesicles (EVs) and extract ethanol-soluble substances from the same S. serratifolium biomass. The extracellular vesicles derived from S. serratifolium (SEVs) were isolated and characterized based on their particle size, morphology, concentration, and cargo molecules, including mRNA and proteins. Their antioxidant and anti-inflammatory activities were evaluated using cellular assays, while their effects on melanogenesis and melanosome transport were assessed in B16F10 melanoma cells. Transcriptomic analysis by RNA sequencing was further performed to investigate the molecular pathways involved in SEV-mediated regulation of melanosome transport. SEVs isolation did not affect the yield or biological activity of the S. serratifolium ethanol-soluble fraction. Based on our previous finding that the ethanol extract of S. serratifolium (ESS) suppresses melanin synthesis, the present study focused on investigating the effects and mechanisms of SEVs on melanogenesis and melanosome transport. SEVs were nanoscale vesicles containing mRNA and proteins and showed antioxidant and anti-inflammatory effects in cellular assays. Although SEVs did not reduce melanin production in B16F10 cells, they significantly inhibited melanosome transport. RNA sequencing suggested that SEVs regulated melanosome transport through pathways related to the extracellular matrix, actin filament organization, and calcium ion homeostasis. These findings suggest that SEVs exert anti-melanogenic effects by targeting melanosome transport, providing a complementary mechanism to the previously reported inhibition of melanin synthesis by ESS. These findings demonstrate a sustainable strategy for producing functional EVs and bioactive extracts from a single S. serratifolium biomass source and support their potential use in cosmetic or therapeutic applications targeting hyperpigmentation.