Search Results (456)

Since 2011, countries across the tropical Atlantic have experienced severe influxes of the seaweed species Sargassum natans and Sargassum fluitans (henceforth, “sargassum”), with nearshore and onshore ecological, economic and social impacts locally and regionally. Not all affected countries have had the same response to this emergent environmental challenge. Here, we explore the first ten years of policies produced in response to sargassum influx risk across islands in the Wider Caribbean Region, considering the variation in form, content and aim of sargassum adaptation policies. This assessment of the variation in Caribbean adaptation policies allows lessons to be identified for rapid adaptation to emergent environmental challenges. We find that several countries have no national policy for sargassum adaptation, and many subnational island jurisdictions have no island-specific policies. Whilst there is increasing anecdotal evidence of private and local adaptations taking place to address sargassum influx events, there remains significant scope for government leadership and resource support in adapting to this emergent threat. The lesson is that private adaptations to emergent threats may be quicker to develop and execute than policy adaptation, but longer-term, larger-scale adaptations depend on evidence-based, widely supported government policies with clear avenues of funding. Full article

A series of in vitro studies were conducted to explore the anti-methanogenic potential of five seaweeds collected from the Indian sea and to optimize the level(s) of incorporation of the most promising seaweed(s) into a straw and concentrate diet to achieve a significant reduction in methane (CH₄) production without disturbing rumen fermentation characteristics. A chemical composition analysis revealed a notable ash content varying between 55 and 70% in seaweeds. The crude protein content was highly variable and ranged between 3.25 and 15.3% of dry matter. Seaweeds contained appreciable concentrations of tannins and saponins. Among the seaweeds, Spyridia filamentosa exhibited significantly higher CH₄ production, whereas the percentage of CH₄ in total gas was significantly lower in the cases of Kappaphycus alvarezii and Sargassum wightii. The ranking of seaweeds in terms of CH₄ production (mL/g OM) is as follows: Sargassum wightii < Kappaphycus alvarezii < Acanthophora specifera < Padina gymnospora < Spyridia filamentosa. A remarkable decrease of 31–42% in CH₄ production was recorded with the incremental inclusion of Kappaphycus alvarezii at levels of 3–5% of the dry matter in the diet. The addition of Sargassum wightii led to a significant decrease of 36–48% in CH₄ emissions when incorporated at levels of 4–5% of dry matter, respectively. The findings of this study revealed a significant decrease in the numbers of total protozoa and Entodinomorphs, coupled with increasing abundances of sulfate-reducing microbes and minor methanogens. Metagenome data revealed that irrespective of the seaweed and treatment, the predominant microbial phyla included Bacteroidota, Bacillota, Pseudomonadota, Actinomycetota, Fibrobacterota, and Euryarchaeota. The prevalence of Methanobrevibacter was similar across treatments, constituting the majority (~79%) of the archaeal community. The results also demonstrated that the supplementation of Kappaphycus alvarezii and Sargassum wightii did not alter the feed fermentation pattern, and therefore, the reduction in CH₄ production in the present study could not be attributed to it. Animal studies are warranted to validate the extent of reduction in CH₄ production and the key processes involved by supplementation with Kappaphycus alvarezii and Sargassum wightii at the recommended levels. Full article

Sargassum fusiforme, an edible seaweed, plays a crucial role in our daily lives by providing essential nutrients, including minerals, to the human body. The detection of mineral content during different growth stages of S. fusiforme benefits the goals of ensuring product quality, meeting diverse consumer needs, and achieving quality classification. Currently, the determination of minerals in S. fusiforme primarily relies on inductively coupled plasma mass spectrometry and other methods, which are time-consuming and labor-intensive. Thus, a rapid and convenient method was developed for the determination of six minerals (i.e., Na, Mg, Ca, Cu, Fe, and K) in S. fusiforme via near-infrared (NIR) spectroscopy based on chemometrics. This study investigated the variations in minerals in S. fusiforme from different growth stages. The effects of four spectral pretreatment methods and three wavelength selection methods, including the synergy interval partial least squares (SI-PLS) algorithm, genetic algorithm (GA), and competitive adaptive reweighted sampling method (CARS) on the model optimization, were evaluated. Superior CARS-PLS models were established for Na, Mg, Ca, Cu, Fe, and K with root mean square error of prediction (RMSEP) values of 0.8196 × 10³ mg kg⁻¹, 0.4370 × 10³ mg kg⁻¹, 1.544 × 10³ mg kg⁻¹, 0.9745 mg kg⁻¹, 49.88 mg kg⁻¹, and 7.762 × 10³ mg kg⁻¹, respectively, and coefficient of determination of prediction (R_P²) values of 0.9787, 0.9371, 0.9913, 0.9909, 0.9874, and 0.9265, respectively. S. fusiforme demonstrated higher levels of Mg and Ca at the seedling stage and lower levels of Cu and Fe at the maturation stage. Additionally, S. fusiforme exhibited higher Na and lower K at the growth stage. NIR combined with CARS-PLS is a potential alternative for monitoring the concentrations of minerals in S. fusiforme at different growth stages, aiding in the convenient evaluation and further grading of the quality of S. fusiforme. Full article

The brown alga Sargassum fusiforme (SF) is historically consumed as a food material in Japan. A steaming process is often required for SF products on the market due to their moderate hardness and astringent taste. This investigation aimed to elucidate the effect of steaming on the anti-diabetic activity of SF and its related chemical components. Acetone extracts of SF were prepared after it were steamed for 0, 1, 2, or 4 h (SF-0h, SF-1h, SF-3h, and SF-4h, respectively). Alpha-glucosidase inhibitory profiles of each SF extract were made based on activity-guided separation. The active fractions were collected and NMR was applied for a further chemical composition analysis. Our results suggested that total polyphenol levels decreased drastically after steaming, which resulted in a drop in α-glucosidase inhibitory activity. The fatty acid, pheophytin a, and pyropheophytin a contents were elevated significantly after steaming, which contributed to the majority of the activity of steamed SF (SF-1h). However, prolonging the steaming time did not significantly affect the activity of SF further since the content of free fatty acids in steamed SF (SF-2h and SF-4h) almost did not change with a longer time of steaming. Moreover, palmitic acid, 8-octadecenoic acid, and tetradecanoic acid were identified as the top three important fatty acids for the inhibition of α-glucosidase by steamed SF. Further molecular docking results revealed that these fatty acids could interact with residues of α-glucosidase via hydrogen bonds, salt bridges, and hydrophobic interactions. In conclusion, steaming altered the α-glucosidase inhibitory properties of SF by changing the contents of polyphenols, fatty acids, and chlorophyll derivatives. Full article

Atopic dermatitis (AD) is a chronic, inflammatory skin condition characterized by severe pruritus and recurrent flare-ups, significantly impacting patients’ quality of life. Current treatments, such as corticosteroids and immunomodulators, often provide symptomatic relief but can lead to adverse effects with prolonged use. Seaweed, a sustainable and nutrient-dense resource, has emerged as a promising alternative due to its rich bioactive compounds—polysaccharides, phlorotannins, polyphenols, and chlorophyll—that offer anti-inflammatory, antioxidant, and immunomodulatory properties. This review explores the therapeutic potential of brown, red, and green algae in alleviating AD symptoms, highlighting the effects of specific species, including Undaria pinnatifida, Laminaria japonica, Chlorella vulgaris, and Sargassum horneri. These seaweeds modulate immune responses, reduce epidermal thickness, and restore skin barrier function, presenting a novel, safe, and effective approach to AD management. Further clinical studies are needed to confirm their efficacy and establish dosing strategies, paving the way for seaweed-derived therapies as natural alternatives in AD treatment. Full article

Macroalgae-derived oils offer a sustainable and environmentally friendly alternative to conventional mineral oils and additives in lubricant formulation. Their favorable fatty acid profiles can contribute to mitigating the environmental impacts caused by using fossil-based products. This study evaluates the potential of Sargassum spp. oil, collected from the Mexican Caribbean, as a lubricity-enhancing additive in synthetic base oils. The impact of Sargassum spp. oil on viscosity and tribological performance was analyzed. The results indicated that Sargassum spp. oil has potential as an anti-wear additive since a formulation using 10% v/v Sargassum spp. oil in a synthetic lubricant (PAO6) resulted in a wear scar diameter value of 703.03 ± 15.56 µm, which is about 10% lower than PAO6 used as commercial synthetic control. Additionally, the formulation significantly enhanced the viscosity index, with a value of 169, which was notably higher than the control (137). The parameter of the coefficient of friction was significantly reduced from 0.1 to 0.08 (about 27%) when using the formulation with 10% v/v Sargassum spp. oil. These findings underline the potential of algae oils as additives in synthetic lubricants, promoting a transition towards greener products and reducing the environmental impact derived from conventional formulations of polyalphaolefins and esters. Full article

The aim of this study was to investigate the effect of ultrasonic treatment on the physicochemical properties and bioactivities of polysaccharides from Sargassum samples (SPs) extracted with different solvents. The alkali-assisted extraction of polysaccharide (SPA), acid-assisted extraction of polysaccharides from (SPB), and hot water extraction of polysaccharides (SPCs) were perofrmed on Sargassum. Ultrasonic treatment was performed with the SPA, SPB, and SPC in turn, and named USPA, USPB, and UPSC, respectively. The results showed that SPs mainly consisted of mannose, glucose, xylose, rhamnose, galactose, fucose, glucuronic acid, mannuronic acid and guluronic acid. The molecular weight of SPA (434.590 kDa) was the lowest under different solvent extractions, and the molecular weights of SPA, SPB, and SPC were reduced after sonication. SPA had a high carbohydrate content of (52.59 ± 5.16)%, and SPC possessed a high sulfate content of (3.90 ± 0.33)%. After ultrasonic treatment, the biological activities of SPs were significantly increased. The α-glucosidase inhibition assay reflected that the IC50 values of the ultrasonic treatment SPs were significantly reduced, and USPA showed the best activity, with an IC50 of (0.058 ± 0.05) mg/mL. Antioxidant assays demonstrated that USPC exhibited greater DPPH- and ABTS-scavenging capacity. In the anti-glycosylation assay, SPs after sonication demonstrated excellent inhibition of glycosylation products and protein oxidation products, with USPA showing the highest inhibition rate. In conclusion, the biological activities of SPs were enhanced after ultrasonic treatment. This study provides a theoretical reference for their use in food and medicines. Full article

This study aimed to improve the nutritional value of Sargassum horneri (SH) and evaluate its effect on rumen fermentation characteristics and greenhouse gas emissions. The first trial estimated the effects of blanching temperatures (21, 60, 70, and 80 °C) and durations (1, 2, and 3 min) on the chemical and mineral content of SH. The second trial evaluated the effects of SH supplementation levels (0, 1, 3, and 5%) and blanching temperatures (21 and 70 °C) on in vitro rumen fermentation characteristics and greenhouse gas emissions. As the blanching temperature and time increased, the dry matter and crude ash content decreased (p < 0.05), and the ether extract, neutral detergent fiber, and acid detergent fiber content increased (p < 0.05). There were significant reductions in Na, K, and As (p < 0.01) when the blanching temperatures increased. As the SH supplementation levels increased, in vitro digestibility of both dry and organic matter decreased (p < 0.001) and the methane production reduced (p < 0.001). Therefore, this study shows that blanching SH at 70 °C for 3 min optimized its nutritional value and improved its potential as a feed source that has methane mitigation characteristics at 3 to 5% supplementation levels. Full article

Sargahydroquinoic acid (SHQA), a bioactive compound found in certain Sargassum species, exhibits significant health benefits. This study optimized the extraction of SHQA from Sargassum yezoense using response surface methodology (RSM) and evaluated its antioxidant effects through in vitro and in vivo assays. A Box–Behnken design (BBD) was effectively employed to investigate the effects of incubation temperature, time, and ethanol concentration on SHQA yield, achieving a high coefficient of determination (R² = 0.961). Analysis of variance (ANOVA) validated the model’s reliability (F = 13.86, p = 0.005) and highlighted ethanol concentration as a highly significant factor (p < 0.001). Optimal extraction conditions were identified as 52.8 °C, 8.3 h, and 74.1% ethanol. The SHQA-maximized extract (SME) contained 67.8 ± 0.6 mg SHQA/g and 25.00 ± 1.01 mg phloroglucinol equivalent/g. SME exhibited antioxidant capacity of 26.45 ± 0.66 mg and 28.74 ± 2.30 mg vitamin C equivalent/g in ABTS and DPPH assays, respectively, and 0.29 ± 0.02 mM FeSO₄ equivalent/g in the FRAP assay. Additionally, SME at 50 µg/mL and SHQA at 1 µg/mL inhibited reactive oxygen species (ROS) generation in an H₂O₂-induced zebrafish model. This study presents the first optimization of SHQA extraction using RSM and demonstrates SHQA’s ROS inhibition in a zebrafish model. Full article

This research focuses on the synthesis and characterization of advanced materials for hydrogen storage. Two biocarbon samples were synthesized from Sargassum spp. The first was activated with KOH (SKPT) and the second was doped with sulfur (SSKTP); both were obtained through pyrolysis at 900 °C. The sulfur-doped biocarbon (SSKTP), with its high specific surface area (2377 m² g^ࢤ1), exhibited enhanced electrocatalytic properties, making it an efficient candidate for hydrogen storage applications. Various characterization techniques were employed to study the relationship between physicochemical properties and hydrogen uptake. The presence of micropores and sulfur doping significantly improved hydrogen uptake at 45 °C and 50 bar, where SSKTP achieved 0.40 wt%. In comparison, the non-doped biocarbon (SKPT) showed a lower hydrogen storage capacity of 0.33 wt%, with a specific surface area of 1620 m² g^ࢤ1. The results highlight the potential of sulfur-doped activated biocarbon as a functional material in energy conversion systems, specifically for electrocatalytic hydrogen storage processes. This study demonstrates a sustainable approach to utilizing biomass waste for advanced electrocatalysts, contributing to renewable energy solutions. Full article

Since 2011, Caribbean territories have experienced massive and repeated sargassum seaweed inundations. Once on shore, sargassum degradation through anaerobic metabolism elicits the release of many noxious molecules, including hydrogen sulfide (H₂S) and ammonia (NH₃). H₂S has been long recognized as a malodorous and highly toxic gas, while chronic exposure has not been extensively explored. Our objective was to assess whether pregnant women exposed to sargassum emissions would be more prone to developing hypertensive disorders compared to unexposed women. We conducted a retrospective study including 3020 pregnant women at the Obstetrics Department of the University Hospital of Martinique between 25 January 2016 and 31 July 2020. Exposure was defined as a distance of less than 2 km between the residence/workplace of the women and the sargassum strandings. Multivariate regression retained age, body mass index, sickle cell disease, primipaternity, gestational diabetes and sargassum emissions exposure as independent predictors of hypertensive events in pregnant women. Jointly with previous studies from our group, this study highlights the deleterious effects of sargassum emissions on human health in individuals chronically exposed to low to moderate H₂S concentrations. Full article

This study represents the first investigation into the ultrasonic and microwave extraction of bioactive metabolites from Jania rubens (J. rubens) (red seaweed) and Sargassum. muticum (S. muticum) (brown seaweed), with a focus on their biological activities. The research compares ultrasound-assisted extraction (UAE) with microwave-assisted extraction (MAE) utilizing a hydromethanolic solvent to evaluate their effects on these seaweeds’ bioactive compounds and biological activities. The assessment included a series of antioxidant essays: DPPH, ABTS, phenanthroline, and total antioxidant capacity, followed by enzyme inhibition activities: alpha-amylase and urease. Results revealed significant proportions of phenolic compounds, ranging from 48.31 ± 0.32 to 74.42 ± 0.80 μg GAE/mg, depending on the extraction method. The extracts demonstrated a high antioxidant activity, with IC₅₀ values ranging from 26.58 ± 0.39 to 87.55 ± 0.69 μg/mL. Notably, the MAE extract of S. muticum showed a value of 48.11 ± 2.75 μg/mL for alpha-amylase inhibition, which is strictly superior to the reference acarbose with an IC₅₀ equal to 3431.01 μg/mL. UPLC-ESI-MS/MS analysis identified 14 bioactive compounds. The proportion of riboflavin with MAE was 70.58% and 59.11% for J. rubens and S. muticum fractions, respectively. These findings underscore the critical influence of extraction technique selection on bioactive compounds’ yield and efficiency, highlighting the potential of algal biomass as a sustainable alternative in various applications. Full article

Seaweeds are a cheap, eco-friendly, and rich source of plant growth stimulators that can mitigate the adverse effects of salinity stress. This study examined the impact of Sargassum bovianum extracts obtained through different techniques using pressure, heat, and microwave radiations on the germination and growth of wheat, corn, and canola seeds under varying salinity levels (500, 3500, and 6500 µS cm⁻¹). The findings showed that pressure, microwave, and acidic extraction methods were the most effective in extracting polysaccharides, alginate, and nutrients from S. bovianum. Seaweed extract significantly improved the mean germination time (MGT) and germination index (GI) of wheat under high salinity stress and had a positive effect on wheat plumule length (PL) and germination percentage (GP). However, seaweed extract had no significant impact on canola seeds in salinity stress, except for improved canola PL. The PL and seedling vigor index (SVI) of corn were enhanced in low salinity levels, but most treatments reduced PL and SVI in high salinity. This study suggests that using heat, pressure, and microwave techniques for seaweed extraction results in higher polysaccharides and alginate content, leading to improved germination and plant growth, particularly in wheat and canola. These findings can help growers optimize the germination and growth of these important crops. Full article

Background: Melanin overproduction leads to pigmented skin diseases. Brown algae polyphenols, non-toxic secondary metabolites, exhibit potential bioactivities. Sargassum fusiforme, an edible seaweed, has been underexplored in the field of beauty despite its polyphenol richness. Methods: Polyphenols from S. fusiforme were extracted using macroporous resin (SFRP) and ethyl acetate (SFEP). Their antioxidant and anti-aging properties, tyrosinase inhibitory activities, and mechanisms were assessed. The melanogenesis inhibition effect and mechanism by SFRP was examined in B16F10 melanoma cells. Results: Both SFRP and SFEP demonstrated scavenging activities against DPPH, superoxide anion, and hydroxyl radicals. SFRP showed stronger anti-collagenase and anti-elastase effects. They dose-dependently inhibited mushroom tyrosinase, with IC50 values of 9.89 μg/mL for SFRP and 0.99 μg/mL for SFEP. SFRP reversibly inhibited tyrosinase, while SFEP showed irreversible inhibition. SFRP also suppressed melanin content and intracellular tyrosinase activity in B16F10 cells, downregulating the expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 1 and 2 expression through the PI3K/Akt and MAPK/ERK signal pathways. Conclusions: S. fusiforme polyphenols, especially SFRP, exhibit promising antioxidant, anti-aging, and melanogenesis inhibitory properties, highlighting their potential application as novel anti-melanogenic agents in cosmetics and the food industry. Full article

Vitamin K (VitK) is a vital nutrient that is newly recognized to support bone and cardiovascular health. As a nutraceutical, VitK is produced via plant extraction and bacterial fermentation. This study examined the potential anti-inflammatory and osteogenic benefits of VitK, i.e., VitK1 (phylloquinone; PK) and VitK2 (menaquinone; MKs), derived from Sargassum fulvellum fermented by Lactococcus lactis and Leuconostoc mesenteroides (SfLlLm) using lipopolysaccharide (LPS)-induced Raw264.7, MC3T3-E1 cells, and ovariectomized (OVX) mice. MK4, MK7, and MK9, as well as PK, were effectively acquired from SfLlLm and analyzed. SfLlLm_VitK reduced levels of proinflammatory cytokine in LPS-induced Raw264.7 cells and induced an osteogenesis regulating factor in MC3T3-E1 cells. In OVX mice, SfLlLm feeding reduced plasma levels of alkaline phosphatase, phosphate, and the pro-collagen type I alpha 2 gene (pro-Col1a2) while elevating cancellous bone volume and trabecular numbers. Accordingly, SfLlLm, comprising MKs, may be a candidate for preventing and treating immune and bone diseases. Full article