Search Results (50)

Fucoidans are sulphated polysaccharides from brown macroalgae that have attracted considerable interest due to their diverse biological activities and potential applications in metabolic health. In this study, fucoidan-rich extracts were obtained from three South African brown macroalgal species, Ecklonia maxima, Ecklonia radiata, and Sargassum incisifolium, and comparatively characterised using biochemical and physicochemical analyses. The extracts were evaluated for carbohydrate, sulphate, L-fucose, protein, polyphenol, and uronic acid contents, while molecular weight distribution, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and proton Nuclear Magnetic Resonance (¹H NMR) spectroscopy were used to investigate structural characteristics. All extracts displayed features characteristic of fucoidans, including sulphated fucose-containing polysaccharides. Notable species-dependent differences were observed, with S. incisifolium exhibiting the highest sulphate (~24%) and polyphenol (~6.76%) contents, stronger sulphate-associated FTIR signals, greater molecular weight heterogeneity, and enhanced thermal stability. The fucoidan-rich extracts exhibited concentration-dependent pancreatic lipase and α-glucosidase inhibitory activities, together with DPPH radical-scavenging activity. At 1.0 mg/mL, S. incisifolium demonstrated approximately 66% DPPH radical scavenging and 49% pancreatic lipase inhibition. S. incisifolium and E. radiata exhibited strong α-glucosidase inhibition, with IC₅₀ values of ~29 and ~46 µg/mL, respectively, compared to ~354 µg/mL for acarbose. The findings highlight South African brown macroalgae as promising sources of fucoidans and contribute to understanding the relationships among fucoidan composition, structure, and bioactivity. Full article

Wounds are an increasing clinical and socioeconomic burden motivating the development of sustainable and biocompatible biomaterials for wound healing. Collagen-based extracellular matrix products can improve healing but are limited by cost and ethical or cultural constraints. Cellulose-rich macroalgal matrices offer a potential sustainable alternative. This pilot study evaluated the biocompatibility and wound-healing performance of brown macroalgal scaffolds. Scaffolds derived from Laminaria digitata (LD) and Saccharina latissima (LS) were produced using the visible-light method. Indirect cytotoxicity was assessed in keratinocytes, and in vivo effects were evaluated in a splinted dorsal excisional wound model in Sprague Dawley rats (n = 24), comparing LD, LS, bacterial cellulose (a CACS), and standard of care (SOC). The LD and LS extracts were non-cytotoxic, and no adverse reactions were observed in vivo. Wounds treated with LD, LS, and the SOC showed faster wound closure than the CACS at intermediate timepoints. Inflammation and foreign-body response scores were low and comparable across all groups. The LD showed significantly greater fibroblast infiltration than the CACS at day 7, and at day 14, the LD group exhibited the highest collagen area fraction. These findings indicate that LD and LS scaffolds are non-cytotoxic, are well-tolerated in vivo, and influence wound repair in full-thickness wound models, warranting further study as sustainable biomaterial. Full article

Brown macroalgal polyphenols, particularly phlorotannins, have demonstrated antioxidant and anti-inflammatory bioactivity, but in vivo evidence remains heterogeneous across organisms, stress models, and preparations. This systematic review and meta-analysis synthesized in vivo evidence on the effects of brown macroalgal polyphenols on oxidative stress-related biomarkers. PubMed, Cochrane, Scopus, and Web of Science were searched. Of 415 records identified, 22 in vivo studies involving zebrafish embryos, mice, and rats met the inclusion criteria. Interventions included extracts, fractions, and purified compounds. Random-effects meta-analyses were performed for prespecified outcomes, with subgroup analyses by compound, macroalgal species, and stressor/model. In zebrafish, brown macroalgal polyphenols reduced ROS generation, lipid peroxidation, and nitric oxide production. In rodents, they increased catalase activity and serum superoxide dismutase, and reduced hepatic malondialdehyde and TBARS, whereas glutathione peroxidase showed no consistent pooled effect. Risk-of-bias assessment using SYRCLE indicated predominantly unclear reporting for randomization, allocation concealment, and blinding, while attrition and reporting domains were mostly low-risk. Overall, brown macroalgal polyphenols show promising antioxidant effects in vivo, but substantial heterogeneity and incomplete methodological reporting limit certainty and preclude direct extrapolation to humans. Full article

The increasing interest in natural versus synthetic additives is a driving force for food industry innovation to develop alternative solutions for food safety and quality. Brown algae, described as containing potential antimicrobial and antioxidant compounds, are promising alternative sources. However, optimized food-grade extracts require preserving their bioactivity. In this study, the effects of seasonality and interannual variation, together with non-thermal high-hydrostatic-pressure (HHP) pretreatment, on the extraction of antioxidant and antimicrobial compounds from the macroalga Ericaria selaginoides, collected from the northwest of Spain between November 2021 and September 2023, were assessed. The HHP pretreatment of fresh algae did not significantly change the yield of the crude extracts and only slightly improved the antimicrobial activity of the extracts against L. monocytogenes, S. aureus and B. cereus, without significantly diminishing the antioxidant activity until 600 MPa for 5 min, the total polyphenol content (TPC), and the chlorophyll A content. Interannual and seasonal variations significantly influenced pigments and protein, carbohydrate and polyphenol contents, together with the antioxidant and antimicrobial activities, of the extracts. By NMR, phloroglucinol was identified as the major secondary metabolite, together with mannitol, alanine and a mixture of meroditerpenoids, which may contribute to the reported activities. The overall results demonstrated the role of environmental factors in driving seasonal and interannual changes in macroalgal metabolism, significantly influencing the bioactive properties of extracts, while the effect of HHP pretreatment was minimal. Full article

Marine-derived bioactive compounds have attracted considerable attention as functional ingredients for food and nutraceutical applications due to their various biological activities. Among marine resources, macroalgae represent a sustainable and abundant source of structurally diverse bioactive compounds, including polyphenols, pigments, and polysaccharides. This review provides a comprehensive overview of macroalgal bioactive compounds, with particular emphasis on their sources, the environmental and seasonal factors influencing their composition, chemical classification and characteristics, extraction technologies, biological properties and food and nutraceutical applications. Particularly, attention is given to the molecular mechanisms underlying their antioxidant and anti-inflammatory effects, including radical scavenging, metal chelation, modulation of endogenous antioxidant defense systems, and regulation of key signaling pathways involved in inflammation. Green extraction techniques and encapsulation strategies for improving the stability, bioavailability, and functionality of macroalgal bioactives are critically discussed. Current applications in foods and nutraceutical products are reviewed alongside the major challenges related to biomass variability, large-scale production, standardization, and regulatory compliance. Overall, macroalgal bioactive compounds represent a promising class of sustainable health-promoting ingredients, and continued advances in cultivation, processing, extraction technologies, formulation, and regulatory frameworks will be essential to support their broader industrial utilization. Full article

Due to large-scale macroalgal blooms, nutrient enrichment, and changes in ocean circulation brought on by climate change, beach-accumulated seaweed (BAS) has quickly become a global environmental and waste-governance concern. Despite degradation and contamination during beach stranding, BAS retains valuable bioactive compounds, including sulfated polysaccharides, phlorotannins, pigments, proteins, peptides, and lipids, which exhibit anti-inflammatory, antioxidant, antimicrobial, antiviral, immunomodulatory, anticancer, and metabolic regulatory activities. This review critically evaluates BAS as a sustainable bioresource by integrating current knowledge on biomass composition, degradation-associated challenges, bioactive properties, valorization pathways, advanced extraction technologies, safety validation, regulatory considerations, and emerging commercialization opportunities. Attention is given to sustainable valorization pathways, ranging from composting and bioenergy production to the recovery of high-value bioactives through enzyme-assisted, green, and advanced extraction technologies. The review further discusses policy and regulatory gaps, contamination challenges, safety validation requirements, and life-cycle sustainability considerations that currently limit industrial adoption. Finally, emerging opportunities involving metabolomics, microbial bioprocessing, artificial intelligence, automation, and nanotechnology are explored as future directions for transforming BAS into a standardized and economically viable feedstock within the circular blue bioeconomy. Establishing harmonized regulatory frameworks and integrating BAS management with Sustainable Development Goals (SDGs) 12 and 14 will be critical for enabling sustainable resource recovery and long-term coastal resilience. Full article

Non-indigenous or alien macroalgae are increasingly recognized as ecological threats, sources of raw material, and reservoirs of bioactive compounds for industry and agriculture. This review analyses the valorization potential of this biomass, focusing on their antifungal and elicitor activities against phytopathogenic fungi, particularly Mediterranean (De Bary) Whetzel, 1945. The literature published since 2020 was retrieved from Scopus using targeted keyword combinations. Three major topics were examined: (i) invasive and beach-cast macroalgal and their ecological context, (ii) antifungal and elicitor properties of macroalgal extracts, and (iii) the use of deep eutectic solvents (DES) for the green extraction of bioactive compounds. Species such as Asparagopsis armata, Rugulopteryx okamurae, and Sargassum muticum have shown promising antifungal and elicitor effects, frequently associated with phenolic compounds and polysaccharides. Extracts from these algae can inhibit the growth of fungi or activate plant defense pathways, providing environmentally friendly alternatives to synthetic pesticides. Moreover, DES and natural DES (NADES) offer tunable, biodegradable solvents capable of efficiently extracting these bioactive molecules while reducing the environmental impact associated with conventional organic solvents. Overall, the valorization of this biomass represents a sustainable strategy that simultaneously mitigates ecological and economic impacts and contributes to the development of sustainable inputs in agriculture. Full article

The present study provides an exhaustive exploration of twelve macroalgal species from the Adriatic Sea, including seven brown algae (Ericaria amentacea, Fucus virsoides, Cutleria multifida, Cystoseira compressa, Cystoseira corniculata, Gongolaria barbata and Padina pavonica), three green algae (Codium adhaerens, Codium vermilara and Ulva lactuca), and two red algae (Scinaia furcellata and Asparagopsis taxiformis). Matrix solid-phase dispersion (MSPD) was applied as the extraction technique, using generally recognized as safe (GRAS) solvents. The bioactive profile of the extracts was assessed through the quantification of total phenolic content (TPC) and antioxidant activity. Among the three phyla, U. lactuca, F. virsoides and S. furcellata exhibited the highest TPC (0.8, 26 and 3.0 mgGAE·g⁻¹) and antioxidant activity (1.9, 38 and 7.5 mgTE·g⁻¹), respectively. Targeted HPLC-MS/MS analysis enabled the identification of nineteen phenolic compounds across all taxa. Chlorophyta showed a characteristic profile enriched in coumarins, benzaldehydes and flavanones, including the selective detection of 7-hydroxycoumarin in species with higher antioxidant potential. Additionally, compounds such as chlorogenic, rosmarinic and caffeic acids exhibited taxon-specific distributions that may explain differences in antioxidant activity. Complementary untargeted ultra-high performance liquid chromatography quadrupole time-of-flight (UHPLC-QToF) metabolomics analysis provided broader coverage, revealing eighty metabolites spanning phenolics, sugars, organic acids, lipids, amino acids and their derivatives. Notably, the proposed detection of fatty acid esters of hydroxy fatty acids (FAHFAs) represents the first report of these compounds in macroalgae, alongside a pronounced presence of sulphated phenolics. Overall, these findings provide a robust baseline on the bioactivity and chemical composition of Adriatic macroalgae, highlighting their value as a natural source of functional compounds. Full article

Macroalgal biomass accumulation in eutrophic coastal lagoons represents both an environmental challenge and an underexploited bioresource. This study evaluates the biostimulant potential of Chaetomorpha linum (C. linum) harvested in the Orbetello Lagoon (Italy) on tomato (Solanum lycopersicum) seed germination and early seedling development. Four extraction strategies were investigated: a phytohormone-enriched fraction (PO), a hydroethanolic reflux extract (CLE), a room-temperature aqueous maceration extract (CLWM), and a mild-water-bath aqueous extract (CLWB). Bioactivity was assessed through controlled laboratory germination assays, comparing germination performance, seedling growth traits, and vigor index against an untreated control and a commercial fertilizer. Across the tested conditions, aqueous formulations exhibited the strongest overall effects, with CLWB providing the most balanced response and increasing seedling vigor by approximately 20–30% relative to the control. Collectively, these results support the valorization of eutrophic C. linum biomass into natural, low-input biostimulants for seed priming applications within sustainable agriculture and circular economy frameworks. Full article

The Portuguese Atlantic coast harbors a remarkably diverse macroalgal flora, shaped by the intersection of Lusitanian, Mediterranean, and boreal biogeographic influences. This diversity is reflected in the rich repertoire of secondary metabolites produced by local seaweeds, including halogenated compounds, terpenoids, phlorotannins, mycosporine like amino acids, sulfated polysaccharides, and unique phenolic structures. These metabolites exhibit a wide range of bioactivities, antioxidant, anti-inflammatory, antimicrobial, antiviral, antifouling, antitumoral, and neuroprotective, positioning Portuguese seaweeds as promising sources of novel bioactive agents. This review synthesizes the current state of knowledge on the chemical diversity and biological properties of metabolites isolated from seaweeds along the Portuguese Atlantic coast. We examine species-specific metabolite profiles, ecological drivers of chemical variability, and advances in extraction, purification, and structural elucidation. Emerging applications in pharmaceuticals, nutraceuticals, cosmeceuticals, and sustainable biomaterials are discussed, alongside the potential of seaweed derived compounds to support blue bioeconomy development. Finally, we identify research gaps and propose future directions for bioprospecting, metabolomics, and biotechnological exploitation of this underexplored marine resource. Full article

Docosahexaenoic acid (DHA), an omega-3 fatty acid essential for human health, is highly prone to oxidation in nanoemulsions due to their large interfacial area and presence of transition metal ions. This study investigated macroalgal chelators for stabilizing DHA-rich nanoemulsions. Sequential enzymatic–alkaline extraction using Alcalase^® produced an extract with the strongest Fe²⁺-chelating activity (IC₅₀ = 1.22 mg/mL), protein content of 10.11 ± 0.15%, and total phenolics ≈ 17 µg GAE/mL. This extract was incorporated into nanoemulsions (5 wt% DHA oil, 1 wt% Tween^® 20) at 0.61, 1.22, and 2.44 mg/mL and compared with controls containing EDTA (0.025 mg/mL) or no antioxidant. Droplet size remained stable (D_3,2 ≈ 77–80 nm; D_4,3 ≈ 199–215 nm) and zeta potential averaged −17 to −19 mV, confirming physical stability. Confocal microscopy revealed concentration-dependent interfacial adsorption of extract components. During iron-accelerated storage, extract-treated nanoemulsions slowed hydroperoxide formation and delayed tocopherol depletion compared to the control, while reducing volatile oxidation markers such as 1-penten-3-ol by up to 40%. However, EDTA consistently provided superior protection against oxidation. These findings highlight the potential of macroalgal extracts as clean-label, natural chelators for mitigating metal-driven oxidation in DHA nanoemulsions, though synthetic chelators remain more effective under severe prooxidant conditions. Full article

Macroalgae are increasingly recognized as a valuable source of nutrients and bioactive compounds for animal nutrition, including for aquatic species. However, the complex structure of the macroalgal cell wall limits the accessibility of intracellular components, restricting their use in feeds. To overcome this limitation, macroalgal hydrolysis using various technological treatments has been tested, often employing a low solid-to-water ratio, which complicates downstream processing due to phase separation. In contrast, high-solids loading hydrolysis has the advantage of producing a single and consolidated fraction, simplifying subsequent processing and application. The present study assessed the effectiveness of high-solids loading water or alkaline (0.5 and 1N NaOH) autoclaving for 30 or 60 min, applied alone or followed by sequential enzymatic hydrolysis, using a xylanase-rich enzymatic complex aimed at promoting cell wall disruption and increasing the extractability of intracellular components in the red macroalga Palmaria palmata with minimal free water. The 1N NaOH treatment for 30 min decreased neutral and acid detergent fiber while increasing Folin–Ciocalteu total phenolic content (GAE) (expressed as gallic acid equivalent) and the water-soluble protein fraction and decreased crude protein, indicating enhanced extractability of these components. Microscopic examination showed relatively mild structural changes on the surface of P. palmata after high-solids loading alkaline (1N NaOH) autoclaving for 30 min. Following alkaline or water treatment, the enzymatic complex hydrolysis further increased the Folin–Ciocalteu total phenolic content (GAE), with minimal effects on NDF, ADF, or crude protein. Overall, these results showed that high-solids loading alkaline autoclaving, with or without subsequent enzymatic hydrolysis, effectively disrupts P. palmata cell walls and induces substantial modifications while simplifying processing by avoiding phase separation. Full article

The increasing environmental impact of synthetic antifouling paints has stimulated the search for natural, eco-friendly alternatives. In this study, alcoholic and aqueous extracts of the macroalgae Ulva ohnoi and Asparagopsis taxiformis were evaluated for their antifouling potential on aluminum substrates representative of boat hulls. Extracts were applied to aluminum plates coated with gelcoat under three different surface conditions (non-worn, worn, highly worn). The treated panels were submerged at 5 m and biofilm and fouling development was monitored every 96 h using digital imaging and quantitative segmentation. All treated surfaces exhibited significantly lower fouling colonization than the untreated control (p < 0.001). Among treatments, the aqueous extract of A. taxiformis produced the lowest degree of colonization across all surface conditions, while U. ohnoi extracts showed moderate antifouling activity. Increased surface wear enhanced overall colonization but did not suppress extract efficacy. These results demonstrate that both algal species possess active compounds capable of inhibiting early biofilm formation on marine substrates. Although less potent than conventional biocidal coatings, their biodegradability and absence of ecotoxicity represent a substantial environmental advantage. Future studies should focus on the chemical characterization of active metabolites, the formulation of hybrid bio-based coatings, and long-term field testing under dynamic marine conditions. Full article

Although extensive research has been conducted on algal polysaccharides worldwide, Mediterranean species remain comparatively understudied, despite the region’s rich biodiversity and the presence of several endemic taxa with promising biotechnological potential. This review provides an overview of the major polysaccharides isolated from Mediterranean macroalgae, highlighting their structural features and bioactivities, as well as potential structure-activity relationships. Furthermore, the extraction and purification strategies used to isolate these biomolecules, ranging from conventional chemical approaches to emerging green technologies, were overlooked. Overall, the growing evidence of potent biological activities, combined with advances in sustainable extraction, underscores the significant potential of Mediterranean macroalgal polysaccharides as valuable resources unlocking new opportunities for their application in pharmaceutical, cosmetic, biomedical, and biotechnology fields. Full article

Macroalgal polysaccharides represent a diverse group of structurally complex biopolymers with significant potential in biomedicine and functional food applications. This review provides a comprehensive examination of their structural features, biological activities, and molecular targets, with an emphasis on precision applications. Key polysaccharides such as alginates, carrageenans, fucoidans, ulvans, and laminarans are highlighted, focusing on their unique chemical backbones, degrees of sulfation, and branching patterns that underlie their bioactivity. Special attention is given to their roles in modulating inflammation, oxidative stress, apoptosis, gut microbiota, and metabolic pathways. Comparative assessment of extraction strategies, structure–function relationships, and bioactivity data highlights the importance of tailoring polysaccharide processing methods to preserve bioefficacy. Emerging insights from computational modelling and receptor-binding studies reveal promising interactions with immune and apoptotic signalling cascades, suggesting new therapeutic opportunities. Finally, the review outlines challenges related to standardisation, scalability, and regulatory approval, while proposing avenues for future research toward clinical translation and industrial innovation. By integrating structural biology, pharmacology, and nutraceutical sciences, this work underscores the potential of macroalgal polysaccharides as precision agents in health-promoting formulations and next-generation functional foods. Full article