A comprehensive review of traditional uses, bioactivity potential, and chemical diversity of the genus Gracilaria (Gracilariales, Rhodophyta)

Life cycle assessment and cost analysis of innovative agar extraction technologies from red seaweeds

Developing efficient and sustainable extraction technologies for valuable biocompounds from seaweed is crucial to overcome the limitations of conventional technologies. This study aims to compare three innovative technologies for agar extraction from two red seaweed species, G. sesquipedale and G. vermiculophylla: subcritical water extraction (performed at 125 °C, 2.5 atm, 1 min, and at 140 °C, 3.8 atm, 1 s), moderate electric fields (applied at 85 °C for 120 min and 95 °C for 180 min), and a combination of both methods. The comparison used life cycle assessment and life cycle costing methodologies, considering a gate-to-gate approach. The combined technology demonstrated the lowest energy consumption, with 67 MJ/kgagar for G. vermiculophylla and 100 MJ/kgagar for G. sesquipedale. A carbon footprint reduction of up to 94 % was obtained when compared to the control, with 15.9 kgCO2 eq. /kgagar for G. vermiculophylla and 20.4 kgCO2 eq. /kgagar for G. sesquipedale. Using photovoltaic panels as alternative energy further cut carbon emissions by 50 %. The cost analysis showed that the combined technology was the most cost-effective extraction method.

Assessment of nutraceutical value, physicochemical, and anti-inflammatory profile of Odonthalia floccose and Odonthalia dentata

The nutraceutical value, and physicochemical profile as well as anti-inflammatory activity potential of Odonthalia floccose and Odonthalia dentata (red macroalgae) dry biomass were investigated in this study. Proximate composition study results revealed that the dry biomass of O. floccose and O. dentae were found to be as ash: 9.11 & 8.7 g 100 g-1, moisture: 8.24 & 8.1 g 100 g-1, total fat: 6.9 & 7.2 g 100 g-1, protein: 24.52 & 25.6 g 100 g-1, and total carbohydrate/polysaccharides: 53.84 & 48.85 g 100 g-1 of dry weight biomass respectively. Both algae biomass contain considerable quantity of minerals (Fe, Cu, Mg, and Zn). Furthermore, the major saturated fatty acids (6.24 & 5.82 g FAME 100 g-1 of total fat of O. floccose and O. dentate) (ΣFAs) present in the test algae were stearic acid, palmitic acid, and margaric acids. O. floccose and O. dentata also contain remarkable protein composition profile that compiled with considerable quantity of essential and non-essential amino acids. The vitamins such as vitamin A, B1, B2, B3, B6, B9, C, and E of O. floccose and O. dentate biomass were also identified at sufficient quantity level. The swelling capacity (SWC), water holding capacity (WHC), and oil holding capacity (OHC) properties of O. floccose and O. dentate at various temperature conditions (25 and 37 ᵒC) were found to be 8.11 & 7.02 mL g-1 and 8.95 & 7.55 mL g-1, 5.1 & 4.87 and 4.8 & 4.1 mL g-1, as well as 2.11 & 1.81 and 1.96 & 1.89 mL g-1 respectively. Among these two marine red macroalgae samples, the O. dentate showed better anti-inflammatory activity than O. floccose at 150 μg mL-1 dosage. Thus, this O. floccose and O. dentate biomass can be considerable as nutritional supplement and pharmaceutical product development related research.

Environmental sustainable treatment and disposal technologies for reservoir wastes: a review

The process of dredging reservoirs serves the purpose of preserving water storage capacity and ensuring the functionality of navigational channels. Additionally, it has the potential to mitigate the presence of pollutants and chemicals that pose risks to both the environment and human well-being. This review article examines the many ways of disposal and treatment of dredged sediment, as well as the ecological and economic advantages associated with these approaches. Algae and reed-based treatment methods have the potential to effectively and economically remediate and sustainably manage dredged sediments. Landfills and ocean dumping are widely utilized methods for the disposal of excavated materials. However, other approaches such as land reclamation, the use of fill material, and the preservation of wetlands can offer cost-effective solutions while also contributing to environmental conservation. The implementation of sediment cleaning, stabilization, and solidification techniques has the potential to effectively mitigate waste and improve the quality of sediment, hence facilitating its reuse. Algae and reed-based treatment systems have been found to effectively mitigate disposal costs and contribute to environmental enhancement. Additionally, the practice of reusing dredged sediments has been recognized as a valuable strategy in promoting a circular economy.

Bioactive Polysaccharides from Gracilaria lemaneiformis: Preparation, Structures, and Therapeutic Insights

Gracilaria lamaneiformis, a red seaweed, is an abundant source of bioactive polysaccharides with significant health-promoting properties. Nevertheless, the broad application of G. lamaneiformis in the nutraceutical and pharmaceutical sectors remains constrained due to the absence of comprehensive data. This review provides a detailed examination of the preparation methods, structural characteristics, and biological activities of G. lamaneiformis polysaccharides (GLPs). We explore both conventional and advanced extraction techniques, highlighting the efficiency and yield improvements achieved through methods such as microwave-, ultrasonic-, and enzyme-assisted extraction. The structural elucidation of GLPs using modern analytical techniques, including high-performance liquid chromatography, gas chromatography, and nuclear magnetic resonance spectroscopy, is discussed, providing comprehensive insights into their molecular composition and configuration. Furthermore, we critically evaluate the diverse biological activities of GLPs, including their antioxidant, anti-inflammatory, antitumor, and gut microbiota modulation properties. This review underscores the therapeutic potential of GLPs and suggests future research directions to fully harness their health benefits.

Edible-algae base composite film containing gelatin for food packaging from macroalgae, Gracilaroid (Gracilaria fisheri)

BACKGROUND

Conventional petroleum-based packaging films cause severe environmental problems. In the present study, bio-edible film was introduced as being safe to replace petroleum-based polymers. A food application for edible sachets and a composite edible film (EF) from marine algae, Gracilaria fisheri (GF) extract, were proposed.

RESULTS

Carbohydrates were the most prevalent component in fresh GF fronds. Under neutral conditions comprising 90 °C for 40 min, the structure of the extract was determined by Fourier transform infrared to be a carrageenan-like polysaccharide. Glycerol was the best plasticizer for EF formation because it had the highest tensile strength (TS). The integration of gelatin into the algal composite film with gelatin (CFG) was validated to be significant. The best casting temperatures for 2 h were 70 and 100 °C among the four tested temperatures (25, 60, 70 and 100 °C). Temperatures did not result in any significant (P ≤ 0.05) differences in any character (color values, TS, water vapor permeability, oxygen transmission, thickness and water activity), except elongation at break. Visually, the CFG had a slightly yellow appearance. The best-to-worst order of film stability in the three tested solvents was oil, distilled water (DW) and ethanol. Its stability in ethanol (0-100%), temperature of DW (30-100 °C) and pH (3-7 in DW) demonstrated inverse relationships with the concentration or different conditions, except for pH 8-10 in DW. All treatments were significantly (P ≤ 0.05) different.

CONCLUSION

The novel material made from polysaccharides from algae, G. fisheri, was used to improve EF. The edible sachet application is plausible from the EF. © 2024 Society of Chemical Industry.

Nutritional and biofunctional characterizations of four novel edible aquatic plants of Bangladesh

Aquatic plants are a cheap and renewable biomass rich in bioactive and biofunctional compounds, holding valorization prospects for use in food and pharmaceuticals. Four commonly found edible aquatic plants in Bangladesh, namely red water lily (Nymphaea nouchali), white water lily (Nympheae alba), malancha (Alternanthera philoxeroides), and red seaweed (Gracilaria tenuistipitata), were compared in terms of proximate composition, bioactive compounds, antioxidant activity, mineral and heavy metal contents, and amino acid composition. The crude protein content was the highest in A. philoxeroids (26.96 %), followed by G. tenuistipitata (25.21 %), N. nouchali (25.14 %), and N. alba (23.54 %). The sequence of crude lipid content of four aquatic plants was A. philoxeroids (4.8 %) > N. nouchali (4.0 %) > G. tenuistipitata (3.4 %) > N. alba (2.4 %). The aquatic plants were rich in carbohydrates, with G. tenuistipitata having 37.02 %, significantly (P < 0.05) lower than N. alba (46.12 %), N. nouchali (45.73 %), and A. philoxeroids (42.88 %). The ash content in the studied plants varied between 14.63 % and 24.97 %. Substantial numbers of bioactive compounds were identified in these plants: 42 in N. alba, 41 in N. nouchali, 40 in A. philoxeroides, and 36 in G. tenuistipitata, as determined by GC-MS analysis. G. tenuistipitata showed the highest amount of total phenolic (121.05 ± 2.43 mg gallic acid equivalent/g) and flavonoid (128.03 ± 0.79 mg quercetin equivalent/g) content. The DPPH, hydrogen peroxide, and ferric reducing power assays showed the free radical scavenging ability increased in a dose dependent manner. These aquatic plants contained substantial amounts of minerals, namely Ca ranging from 42.05 ± 2.34 to 441.65 ± 4.67 mg/kg, K ranging from 80.15 ± 1.82 to 97.81 ± 1.74 mg/kg, and Na ranging from 41.16 ± 1.32 to 53.37 ± 1.64 mg/kg. The heavy metal contents of Cu, Ni, and Pb were 0.93 ± 0.06 to 1.25 ± 0.09 mg/kg, 0.44 ± 0.02 to 3.86 ± 0.56 mg/kg, and 0.22 ± 0.02 to 0.67 ± 0.05 mg/kg, respectively. Thirteen different amino acids were identified, with leucine, glycine, alanine, lysine, and phenylalanine dominating, and their contents varying by species. Therefore, regular consumption of these aquatic plants might be a healthy approach to addressing malnutrition and enhancing biofunctional activities.

Nutritional composition and phenolic contents of Gracilariopsis longissima, Padina tetrastromatica and Ulva intestinalis from the Bay of Bengal, Bangladesh coast

Seaweeds have become the focus of experts in recent years due to their biological characteristics and the variety of uses they have for both humans and animals. Biochemical composition, amino acids, fatty acids, and phenolic components were analyzed to explore the nutritive value of Gracilariopsis longissima, Padina tetrastromatica, and Ulva intestinalis from the Bay of Bengal, Bangladesh coast. Proximate composition and mineral content were determined according to the AOAC method. The high-performance liquid chromatography amino acid analysis system was used for the amino acid analysis and the fatty acid profile of the extracted oils was assessed as their methyl esters. The Folin-Ciocalteu technique was used to estimate the phenolic content and the aluminum chloride colorimetric technique was used to calculate the total flavonoid content. The three different species of seaweed had significantly different proximate compositions (P < 0.05), with G. longissima having the highest protein content. Except for sulfur, the mineral contents were likewise considerably higher (P < 0.05) in G. longissima. Although the amounts of the essential amino acids were greater than 50 % of the total amino acids in the three studied seaweed species, the total amino acid composition of these three species differed significantly (P < 0.05). The findings indicated that lipid levels were low in all the assessed species, but unsaturated fatty acid levels were high, with G. longissima exhibiting the highest amounts. The results showed that, compared to the other species, G. longissima had a substantially higher (P < 0.05) level of total phenolic and flavonoid content. The three studied seaweed appear to be excellent for nutrition based on their overall nutritional profiles. However, due to high protein, unsaturated fatty acid, essential amino acid, and total phenolic and flavonoid content, G. longissima is the most promising seaweed that will be helpful for pharmaceutical and multifunctional food applications.

Chemical characterization of polysaccharides from Gracilaria gracilis from Bizerte (Tunisia)

Polysaccharides were extracted from Gracilaria gracilis collected from Manzel Jemil Lake in Bizerte Tunisia, with two different solvents (water and NaOH 0.3 M). Different assays were performed on samples (total sugars, neutral sugars, uronic acids, anhydrogalactose, proteins, sulphates, pyruvates), followed by high performance anion-exchange chromatography (HPAEC) to observe the monosaccharide composition, high pressure size exclusion chromatography with multi-angle laser light scattering (HPSEC-MALS) to obtain the molecular mass, Fourier transform infrared spectroscopy (FTIR), and 1D and 2D nuclear magnetic resonance (NMR) to access to structural data. Results have shown that the polysaccharide extracted from Gracilaria gracilis collected from Manzel Jemil Lake in Bizerte Tunisia, is of agar type but with high molecular mass and some original structural features. Hence, the sample was found to contain 9 % of pyruvate groups and is partly sulphated at the C4 of β-d-galactose and methylated on C2 of anhydro-α-l-galactose. The polymer from G. gracilis from Bizerte thus presents a never described structure that could be interesting for further rheological or biological activities applications.

Ethanolic extract of Gracilaria spp. Attenuates the inflammatory stage of oral mucosa wound healing: An in vivo study

Millions of bacteria present in the mouth cavity contribute to the challenging management of oral mucosa injury. On the other hand, Gracilaria spp. (red algae) is one of the widely cultivated algae that have a strong potential as a wound-healing agent for oral mucosa injury. This study aimed to investigate the wound-healing property of the red algae by observing its effect on polymorphonuclear (PMN), a neutrophil that is usually recruited during the initial wound healing. The extract was obtained through maceration and used as bioactive ingredient in gel preparation. Rattus norvegicus with incision wounds in the oral mucosa was used as the animal model. Our results revealed that rats treated with the red algae gel had significantly lower PMN on the injury site (P < 0.01) as observed on days 1, 3, and 5. Identification using gas chromatography-mass spectrometry showed that the extract was rich in hexadecenoic acid and glycerol. The brine shrimp lethality test suggested low cytotoxicity of this extract with LC50 = 10694.93 mg/mL. In conclusion, the extract could be potentially used as bioactive ingredient in gel formulation for topical management of oral mucosa wounds. Further, research to confirm these findings is warranted.

Assessing the effect of Maillard reaction products on the functionality and antioxidant properties of Amaranth-red seaweed blends

Plant-based proteins, represented by amaranth in our study, embrace a potential as an ingredient for the functional-food formulation. However, their efficacy is hindered by inherent limitations in solubility, emulsification, and antioxidant traits. The Maillard reaction, a complex chemical-process resulting in a diverse array of products, including Maillard conjugates and Maillard reaction products (MRPs), can employ variable effects on these specific attributes. To elucidate the influence of this reaction and the MRPs on the aforementioned properties, we used a complex blend of dehydrated seaweed Gracilaria and amaranth protein to create a conjugate-MRP blend. Our investigations revealed that the resultant incorporation enhanced solubility, emulsification, and antioxidant properties, while the intermediates formed did not progress to advanced glycation stages. This change is likely attributed to the dual effect of conjugates that altered the secondary protein structure, while the generation and/or preservation of MRPs post ultrasonication and spray drying enhanced its antioxidant potential.

Biotechnological Potential of Macroalgae during Seasonal Blooms for Sustainable Production of UV-Absorbing Compounds

Marine macroalgae (seaweeds) are important primary global producers, with a wide distribution in oceans around the world from polar to tropical regions. Most of these species are exposed to variable environmental conditions, such as abiotic (e.g., light irradiance, temperature variations, nutrient availability, salinity levels) and biotic factors (e.g., grazing and pathogen exposure). As a result, macroalgae developed numerous important strategies to increase their adaptability, including synthesizing secondary metabolites, which have promising biotechnological applications, such as UV-absorbing Mycosporine-Like Amino Acid (MAAs). MAAs are small, water-soluble, UV-absorbing compounds that are commonly found in many marine organisms and are characterized by promising antioxidative, anti-inflammatory and photoprotective properties. However, the widespread use of MAAs by humans is often restricted by their limited bioavailability, limited success in heterologous expression systems, and low quantities recovered from the natural environment. In contrast, bloom-forming macroalgal species from all three major macroalgal clades (Chlorophyta, Phaeophyceae, and Rhodophyta) occasionally form algal blooms, resulting in a rapid increase in algal abundance and high biomass production. This review focuses on the bloom-forming species capable of producing pharmacologically important compounds, including MAAs, and the application of proteomics in facilitating macroalgal use in overcoming current environmental and biotechnological challenges.

Sulfated Galactans from Agarophytes: Review of Extraction Methods, Structural Features, and Biological Activities

Agarophytes are important seaweeds of the Rhodophyta type, which have been highly exploited for industrial use as sources of a widely consumed polysaccharide of agar. In addition to that, sulfated galactans (SGs) from agarophytes, which consist of various functional sulfate groups, have attracted the attention of scientists in current studies. SGs possess various biological activities, such as anti-tumor, anticoagulant, anti-inflammatory, antioxidant, anti-obesity, anti-diabetic, anti-microbial, anti-diarrhea, and gut microbiota regulation properties. Meanwhile, the taxonomy, ecological factors, i.e., environmental factors, and harvest period, as well as preparation methods, i.e., the pretreatment, extraction, and purification conditions, have been found to influence the chemical compositions and fine structures of SGs, which have, further, been shown to have an impact on their biological activities. However, the gaps in the knowledge of the properties of SGs due to the above complex factors have hindered their industrial application. The aim of this paper is to collect and systematically review the scientific evidence about SGs and, thus, to pave the way for broader and otherwise valuable industrial applications of agarophytes for human enterprise. In the future, this harvested biomass could be sustainably used not only as a source of agar production but also as natural materials in functional food and pharmaceutical industries.

Exploring the hidden treasures of Nitella hyalina: a comprehensive study on its biological compounds, nutritional profile, and unveiling its antimicrobial, antioxidative, and hypoglycemic properties

Macroalgae has the potential to be a precious resource in food, pharmaceutical, and nutraceutical industries. Therefore, the present study was carried out to identify and quantify the phyco-chemicals and to assess the nutritional profile, antimicrobial, antioxidant, and anti-diabetic properties of Nitella hyalina extracts. Nutritional composition revealed0.05 ± 2.40% ash content, followed by crude protein (24.66 ± 0.95%), crude fat (17.66 ± 1.42%), crude fiber (2.17 ± 0.91%), moisture content (15.46 ± 0.48%) and calculated energy value (173.50 ± 2.90 Kcal/100 g). 23 compounds were identified through GC-MS analysis in ethyl acetate extract, with primary compounds being Palmitic acid, methyl ester, (Z)-9-Hexadecenoic acid, methyl ester, and Methyl tetra decanoate. Whereas 15 compounds were identified in n-butanol extract, with the major compounds being Tetra decanoic acid, 9-hexadecanoic acid, Methyl pentopyranoside, and undecane. FT-IR spectroscopy confirmed the presence of alcoholic phenol, saturated aliphatic compounds, lipids, carboxylic acid, carbonyl, aromatic components, amine, alkyl halides, alkene, and halogen compounds. Moreover, n-butanol contains 1.663 ± 0.768 mg GAE/g, of total phenolic contents (TPC,) and 2.050 ± 0.143 QE/g of total flavonoid contents (TFC), followed by ethyl acetate extract, i.e. 1.043 ± 0.961 mg GAE/g and 1.730 ± 0.311 mg QE/g respectively. Anti-radical scavenging effect in a range of 34.55-46.35% and 35.39-41.79% was measured for n-butanol and ethyl acetate extracts, respectively. Antimicrobial results declared that n-butanol extract had the highest growth inhibitory effect, followed by ethyl acetate extract. Pseudomonas aeruginosa was reported to be the most susceptible strain, followed by Staphylococcus aureus and Escherichia coli, while Candida albicans showed the least inhibition at all concentrations. In-vivo hypoglycemic study revealed that both extracts exhibited dose-dependent activity. Significant hypoglycemic activity was observed at a dose of 300 mg/kg- 1 after 6 h i.e. 241.50 ± 2.88, followed by doses of 200 and 100 mg/kg- 1 (245.17 ± 3.43 and 250.67 ± 7.45, respectively) for n-butanol extract. In conclusion, the macroalgae demonstrated potency concerning antioxidant, antimicrobial, and hypoglycemic properties.

Rehashing Our Insight of Seaweeds as a Potential Source of Foods, Nutraceuticals, and Pharmaceuticals

In a few Southeast Asian nations, seaweeds have been a staple of the cuisine since prehistoric times. Seaweeds are currently becoming more and more popular around the world due to their superior nutritional value and medicinal properties. This is because of rising seaweed production on a global scale and substantial research on their composition and bioactivities over the past 20 years. By reviewing several articles in the literature, this review aimed to provide comprehensive information about the primary and secondary metabolites and various classes of bioactive compounds, such as polysaccharides, polyphenols, proteins, and essential fatty acids, along with their bioactivities, in a single article. This review also highlights the potential of seaweeds in the development of nutraceuticals, with a particular focus on their ability to enhance human health and overall well-being. In addition, we discuss the challenges and potential opportunities associated with the advancement of pharmaceuticals and nutraceuticals derived from seaweeds, as well as their incorporation into different industrial sectors. Furthermore, we find that many bioactive constituents found in seaweeds have demonstrated potential in terms of different therapeutic attributes, including antioxidative, anti-inflammatory, anticancer, and other properties. In conclusion, seaweed-based bioactive compounds have a huge potential to play an important role in the food, nutraceutical, and pharmaceutical sectors. However, future research should pay more attention to developing efficient techniques for the extraction and purification of compounds as well as their toxicity analysis, clinical efficacy, mode of action, and interactions with regular diets.

Stabilization of High Internal Phase Oil-in-Water Emulsions Using "Whole" Gracilaria lemaneiformis Slurry

In this study, a Gracilaria lemaneiformis slurry (GLS) was prepared using low-energy mechanical shearing. The resulting GLS, which was rich in polysaccharides, was utilized as an effective stabilizer for oil-in-water emulsions. The microstructures and stability of the resulting emulsions were controlled by adjusting the emulsion formulations, including Gracilaria lemaneiformis (GL) mass concentration and oil volume fraction (φ). The optimized GL mass concentration and φ conditions yielded high internal phase emulsions (HIPEs) with gel-like textures. Moreover, the presence of exogenous Ca2+ resulted in bridging structures in the emulsions, enhancing their viscoelasticity and forming a robust physical barrier against droplet coalescence. Our findings highlight the effectiveness of the GLS as an emulsifier for stabilizing HIPEs. Notably, this method relies solely on physical processes, aligning with the desirability of avoiding chemical additives, particularly in the food industry.

Next-Generation Organic Beauty Products Obtained from Algal Secondary Metabolites: A Sustainable Development in Cosmeceutical Industries

Algae lay over most of the earth's habitats, and it is said that there are more algal cells in water than there are stars in the sky. They are among the wealthiest marine resources that are to be deemed harmless, with hardly any deleterious consequences. Recently, they have received a lot of consideration to be used in cosmeceuticals. Cosmetics encompass synthetic concoctions that are extremely toxic to the environment. Due to their higher molecular size, synthetic cosmetic items induce undesirable side effects and inadequate absorption rates. Consequently, utilizing algae or their secondary metabolites in cosmetics has won multiple votes. Various secondary metabolites synthesized from algae are known to provide skin advantages, such as ultraviolet protection and reduction of skin flaccidity, rough texture, and wrinkles. The tangent drawn here using algae reduces the inorganic/organic chemicals used in the industry that are known to accumulate and affect other organisms and thus opens a pandora's box of ways to a less-polluted environment. The alga is indeed very intriguing. According to the reported studies, algal cells provide biosorption, bio-assimilation, biotransformation, and biodegradation, making them suitable for the eradication of chronic and harmful contaminants from the environment. Another rapid innovation is the product's sustainability. While presenting and marketing new algal products, cosmetics producers have greatly highlighted that they are eco-friendly. This review thus accentuates the significance of using algae and their secondary metabolites in cosmetics to produce extensive variety of products that include sunscreens, moisturizers, anti-aging creams, colorants, and hair care items and extensive insight on the possible remedial capacities of algae species against environmentally dangerous substances in the context of cosmetic chemicals.

Evaluation of 3 northwest European seaweed species on enteric methane production and lactational performance of Holstein-Friesian dairy cows

Seaweeds have been studied for their ability to reduce enteric methane emissions of ruminants when fed as a feed supplement. In vivo research with dairy cattle is mainly limited to the seaweed species Ascophyllum nodosum and Asparagopsis taxiformis, whereas in vitro gas production research covers a broader range of brown, red, and green seaweed species from different regions. The objective of the present study was to determine the effect of Chondrus crispus (Rhodophyta), Saccharina latissima (Phaeophyta), and Fucus serratus (Phaeophyta), 3 common northwest European seaweeds, on enteric methane production and lactational performance of dairy cattle. Sixty-four Holstein-Friesian dairy cattle (16 primiparous, 48 multiparous) averaging (mean ± standard deviation) 91 ± 22.6 d in milk and 35.4 ± 8.13 kg/d fat- and protein-corrected milk yield (FPCM) were randomly assigned to 1 of 4 treatments in a randomized complete block design. Cows were fed a partial mixed ration [54.2% grass silage, 20.8% corn silage, and 25.0% concentrate; dry matter (DM) basis] with additional concentrate bait in the milking parlor and the GreenFeed system (C-Lock Inc.). The 4 treatments consisted of a control diet without seaweed supplement (CON), or CON supplemented with 150 g/d (fresh weight of dried seaweed) of either C. crispus (CC), S. latissima (SL), or a 50/50 mix (DM basis) of F. serratus and S. latissima. Milk yield (28.7 vs. 27.5 kg/d, respectively), fat- and protein-corrected milk (FPCM) yield (31.4 vs. 30.2 kg/d, respectively), milk lactose content (4.57 vs. 4.52%, respectively), and lactose yield (1,308 vs. 1,246 g/d, respectively) increased for SL compared with CON. Milk protein content was lower for SL compared with the other treatments. Milk fat and protein contents; yields of fat, protein, lactose, and FPCM; feed efficiency; milk nitrogen efficiency; and somatic cell count did not differ between CON and the other treatments. Depending on week of experiment, milk urea content was higher for SL compared with CON and CC. No effects were observed of the treatments compared with CON for DM intake, number of visits to the GreenFeed, or gas emission (production, yield, or intensity) of CO₂, CH₄, and H₂. In conclusion, the seaweeds evaluated did not decrease enteric CH₄ emissions and did not negatively affect feed intake and lactational performance of dairy cattle. Milk yield, FPCM yield, milk lactose content, and lactose yield increased, and milk protein content decreased, with S. latissima.

Indoor and Outdoor Cultures of Gracilaria chilensis: Determination of Biomass Growth and Molecular Markers for Biomass Quality Evaluation

Taking into consideration climate change scenarios, marine contamination, and a constantly expanding world population, seaweed aquaculture has become an important option for the large-scale production of high-quality biomass. Due to existing biological knowledge of Gracilaria chilensis, several cultivation strategies have been established for obtaining diverse biomolecules (lipids, fatty acids, pigments, among others) with nutraceutical properties. In this research, indoor and outdoor cultivation methodologies were applied to generate high biomass of G. chilensis with positive quality for productive purposes, where the quality was determined according to the concentrations of lipoperoxides and phenolic compounds and the total antioxidant capacity (TAC). The results showed that G. chilensis cultures, which were fertilized for three weeks with Basfoliar^® Aktiv (BF) at concentrations of 0.05-1% v/v, obtained high biomass (1-1.3 kg m^-2) and DGR (0.35-4.66% d^-1), low lipoperoxides (0.5-2.8 µmol g^-1 DT), and high phenolic compounds (0.4-0.92 µ eq. GA g^-1 FT) and TAC (5-7.5 nmol eq. TROLOX g^-1 FT) as compared with other culture media. Lower stress was determined under indoor cultures, due to the operative control of diverse physicochemical stressor parameters (T°, light intensity, photoperiod, among others). Therefore, the cultures developed allow scaling the biomass in productive terms and are suitable for obtaining compounds of interest.

Evaluation of growth, primary productivity, nutritional composition, redox state, and antimicrobial activity of red seaweeds Gracilaria debilis and Gracilaria foliifera under pCO2-induced seawater acidification

The genus Gracilaria is an economically important group of seaweeds as several species are utilized for various products such as agar, used in medicines, human diets, and poultry feed. Hence, it is imperative to understand their response to predicted ocean acidification conditions. In the present work, we have evaluated the response of Gracilaria foliifera and Gracilaria debilis to carbon dioxide (pCO₂) induced seawater acidification (pH 7.7) for two weeks in a controlled laboratory conditions. As a response variable, we have measured growth, productivity, redox state, primary and secondary metabolites, and mineral compositions. We found a general increase in the daily growth rate, primary productivity, and tissue chemical composition (such as pigments, soluble and insoluble sugars, amino acids, and fatty acids), but a decrease in the mineral contents under the acidified condition. Under acidification, there was a decrease in malondialdehyde. However, there were no significant changes in the total antioxidant capacity and a majority of enzymatic and non-enzymatic antioxidants, except for an increase in tocopherols, ascorbate and glutathione-s-transferase in G. foliifera. These results indicate that elevated pCO₂ will benefit the growth of the studied species. No sign of oxidative stress markers indicating the acclimatory response of these seaweeds towards lowered pH conditions. Besides, we also found increased antimicrobial activities of acidified samples against several of the tested food pathogens. Based on these observations, we suggest that Gracilaria spp. will be benefitted from the predicted future acidified ocean.

Research progress in the preparation, structural characterization, bioactivities, and potential applications of sulfated agarans from the genus Gracilaria

The genus Gracilaria produces 80% of the world's industrial agar. Agar of this genus is a promising biologically active polymer, which has been used in the human diet and folk medicine, alternative for weight loss, treatment of diarrhea, etc. With more attention paid to the genus Gracilaria-sulfated agarans (GSAs), they exhibited multitudinous health benefits in antioxidant, antiviral, antibacterial, prebiotics, anti-tumor, anticoagulant, and antidiabetic. Various preparation procedures of GSAs making the diversities of structure and biological activity. Therefore, this review summarized the isolation, identification, bioactivity potentials, and applications of GSAs, providing a reference to the development of GSAs in functional food and pharmaceutical industry. PRACTICAL APPLICATIONS: The genus Gracilaria is known as a raw material for agar extraction. GSAs are food-grade agaran with the properties of thermoreversible gels at low concentrations, which are commonly used as an additive for making candies as well as raw material for making soup and snacks. They are used in folk medicine to treat diarrhea and other diseases. As an important bioactive macromolecule, GSAs have various biological activities (such as antioxidant, antiviral, antibacterial, probiotic, anti-tumor, anticoagulant, and antidiabetic activities), and have the potential to be developed as functional food and medicine. They could also be used to create innovative agar-based products such as antibacterial films and drug carriers.

Differential responses of bloom-forming Ulva intestinalis and economically important Gracilariopsis lemaneiformis to marine heatwaves under changing nitrate conditions

Marine heatwaves (MHWs) are affecting the survival of macroalgae. However, little is known regarding how the impacts of MHWs are regulated by nitrogen availability. In this study, we investigated the physiological and genetic responses of a green-tide macroalga Ulva intestinalis Linnaeus and a commercially cultivated macroalga Gracilariopsis lemaneiformis (Bory) E.Y. Dawson, Acleto & Foldvik under different nitrate conditions to simulated MHWs. Under nitrogen limited conditions (LN), heatwaves did not significantly affect biomass or Fv/Fm of U. intestinalis although it led to an earlier biomass decline due to more reproduction events, and meanwhile an upregulation in genes related to TCA cycle and oxidative phosphorylation was detected, supporting sporulation. Under nitrogen replete conditions (HN), heatwaves did not change biomass, Fv/Fm or photosynthetic pigments but reduced reproduction rate along with insignificant change of oxidative phosphorylation and TCA cycle related genes. Meanwhile, genes related to photosynthesis and glutathione metabolism were upregulated. Regarding G. lemaneiformis, heatwaves reduced its Fv/Fm and photosynthetic pigments content, leading to bleaching and death, and photosynthesis-related genes were also downregulated at LN. Fv/Fm was improved and photosynthesis-related genes were up-regulated by the combination of nitrogen enrichment and heatwaves, whereas G. lemaneiformis remained bleached and died by day 12. Therefore, U. intestinalis could survive heatwaves through shifting to micropropagules at LN and protecting its photosynthesis at HN. In contrast, G. lemaneiformis died of bleaching when suffering heatwaves regardless of nitrogen availability. These findings suggest that in future oceans with eutrophication and MHWs, the harmful alga U. intestinalis may have more advantages over the economic alga G. lemaneiformis.

The Controlled Semi-Solid Fermentation of Seaweeds as a Strategy for Their Stabilization and New Food Applications

For centuries, macroalgae, or seaweeds, have been a significant part of East Asian diets. In Europe, seaweeds are not considered traditional foods, even though they are increasingly popular in Western diets in human food applications. In this study, a biological processing method based on semi-solid fermentation was optimized for the treatment of the seaweed Gracilaria gracilis. For the first time, selected lactic acid bacteria and non-conventional coagulase-negative staphylococci were used as starter preparations for driving a bio-processing and bio-stabilization of raw macroalga material to obtain new seaweed-based food prototypes for human consumption. Definite food safety and process hygiene criteria were identified and successfully applied. The obtained fermented products did not show any presence of pathogenic or spoilage microorganisms, thereby indicating safety and good shelf life. Lactobacillus acidophilus-treated seaweeds revealed higher α-amylase, protease, lipase, endo-cellulase, and endo-xylanase activity than in the untreated sample. This fermented sample showed a balanced n-6/n-3 fatty acid ratio. SBM-11 (Lactobacillus sakei, Staphylococcus carnosus and Staphylococcus xylosus) and PROMIX 1 (Staphylococcus xylosus) treated samples showed fatty acid compositions that were considered of good nutritional quality and contained relevant amounts of isoprenoids (vitamin E and A). All the starters improved the nutritional value of the seaweeds by significantly reducing the insoluble indigestible fractions. Preliminary data were obtained on the cytocompatibility of G. gracilis fermented products by in vitro tests. This approach served as a valid strategy for the easy bio-stabilization of this valuable but perishable food resource and could boost its employment for newly designed seaweed-based food products.

Identification and determination of optimum growth condition with respect to selected environmental parameters for open sea cultivation of Gracillaria edulis in Andaman water

Gracilaria edulis is one of India's most widely cultivated seaweeds. Pilot scale cultivation of Gracilaria edulis was initiated at Andaman, India for the first time. In the present study attempt has been made to identify how different water quality parameters influence the growth. Total 11 physicochemical parameters and 9 microbiological parameters, as well as chlorophyll and zooplankton, phytoplankton parameters were studied for two different seasons to evaluate which parameters influence seaweed growth. Six (nitrate, nitrite, ammonia, silicate, chlorophyll, photosynthetic active radiation) have a positive impact on seaweed growth, while some of the bacterial species showed negative impact. Lowess 3D curve fit model showed pH range from 7.59 to 7.82, N/P ratio of 2.046, rainfall 23.85-24 mm, and Photosynthetic active radiation of 376.6 W/m² are optimum for Gracillaria growth. This model can be applied to future mass culture.

Paramylon and Other Bioactive Molecules in Micro and Macroalgae

Many algae synthesize compounds that have exceptional properties of nutraceutical, pharmacological, and biomedical interest. Pigments, fatty acids, phenols, and polysaccharides are among the main compounds investigated so far. Polysaccharides are the most exploited compounds, widely used in pharmaceutical, food, and chemical industries, which are at present entering into more advanced applications by gaining importance, from a therapeutic point of view, as antioxidant, antimicrobial, antitumor, and immunomodulatory agents. Establishing algae as an alternative supplement would complement the sustainable and environmental requirements in the framework of human health and well-being. This review focuses on the proprieties and uses of the main micro- and macroalgae metabolites, describing their potential for application in the different industrial sectors, from food/feed to chemical and pharmacological. Further, current technologies involved in bioactive molecule extraction strategies are documented.

Depolymerized Fractions of Sulfated Galactans Extracted from Gracilaria fisheri and Their Antibacterial Activity against Vibrio parahaemolyticus and Vibrio harveyi

Various seaweed sulfated polysaccharides have been explored for antimicrobial application. This study aimed to evaluate the antibacterial activity of the native Gracilaria fisheri sulfated galactans (NSG) and depolymerized fractions against the marine pathogenic bacteria Vibrio parahaemolyticus and Vibrio harveyi. NSG was hydrolyzed in different concentrations of H₂O₂ to generate sulfated galactans degraded fractions (SGF). The molecular weight, structural characteristics, and physicochemical parameters of both NSG and SGF were determined. The results revealed that the high molecular weight NSG (228.33 kDa) was significantly degraded to SGFs of 115.76, 3.79, and 3.19 kDa by hydrolysis with 0.4, 2, and 10% H₂O₂, respectively. The Fourier transformed spectroscopy (FTIR) and ¹H− and ¹³C−Nuclear magnetic resonance (NMR) analyses demonstrated that the polysaccharide chain structure of SGFs was not affected by H₂O₂ degradation, but alterations were detected at the peak positions of some functional groups. In vitro study showed that SGFs significantly exerted a stronger antibacterial activity against V. parahaemolyticus and V. harveyi than NSG, which might be due to the low molecular weight and higher sulfation properties of SGF. SGF disrupted the bacterial cell membrane, resulting in leakage of intracellular biological components, and subsequently, cell death. Taken together, this study provides a basis for the exploitation and utilization of low-molecular-weight sulfated galactans from G. fisheri to prevent and control the shrimp pathogens.

Biological Potential, Gastrointestinal Digestion, Absorption, and Bioavailability of Algae-Derived Compounds with Neuroprotective Activity: A Comprehensive Review

Currently, there is no known cure for neurodegenerative disease. However, the available therapies aim to manage some of the symptoms of the disease. Human neurodegenerative diseases are a heterogeneous group of illnesses characterized by progressive loss of neuronal cells and nervous system dysfunction related to several mechanisms such as protein aggregation, neuroinflammation, oxidative stress, and neurotransmission dysfunction. Neuroprotective compounds are essential in the prevention and management of neurodegenerative diseases. This review will focus on the neurodegeneration mechanisms and the compounds (proteins, polyunsaturated fatty acids (PUFAs), polysaccharides, carotenoids, phycobiliproteins, phenolic compounds, among others) present in seaweeds that have shown in vivo and in vitro neuroprotective activity. Additionally, it will cover the recent findings on the neuroprotective effects of bioactive compounds from macroalgae, with a focus on their biological potential and possible mechanism of action, including microbiota modulation. Furthermore, gastrointestinal digestion, absorption, and bioavailability will be discussed. Moreover, the clinical trials using seaweed-based drugs or extracts to treat neurodegenerative disorders will be presented, showing the real potential and limitations that a specific metabolite or extract may have as a new therapeutic agent considering the recent approval of a seaweed-based drug to treat Alzheimer’s disease.

Enhanced Liberation of Soluble Sugar, Protein, and R-Phycoerythrin Under Enzyme-Assisted Extraction on Dried and Fresh Gracilaria gracilis Biomass

This study aims to investigate the bio-refinery process through an enzyme-assisted extraction (EAE) on freeze-dried and fresh macroalgae Gracilaria gracilis for the release of water-soluble components (R-phycoerythrin, proteins, and sugar). Three enzymes, cellulase, protease, and enzyme cocktail (mixture of cellulase and protease), were applied in the study. Results showed that freeze-dried biomass yielded the highest target components in the presence of enzyme cocktail while a single enzyme was better with fresh biomass, either protease for the release of R-PE and protein or cellulase for sugar. The extraction of protein and sugar was improved by 43% and 57%, respectively, from fresh biomass compared to dried biomass. The difference of biomass status was shown to affect the required enzyme and recovery yield during the extraction process. Employing an enzyme cocktail on freeze-dried biomass boosted the extraction yield, which was probably due to the complementary effect between enzymes. On the other hand, single enzyme worked better on fresh biomass, giving economic benefits (enzyme limitation and drying stage) for further implementation of the bio-refinery process. Thus, biomass treatment (fresh or freeze-dried) and enzyme-type determined the efficiency of enzyme-assisted extraction according to the target components.

Preparation and intrinsic kinetics study of the scale-up production of hydroxypropyl agar by heterogeneous hydroxypropylation reaction

Hydroxypropylation is effective in modifying the structure and properties of agar. So far, the industrial scale-up production of hydroxypropylated agar has not been evaluated. Therefore, the large-scale production of the hydroxypropylation of agar using a heterogeneous reaction system was evaluated in the present this study. The structures and properties of the hydroxypropyl agar (HPA) product were measured and the intrinsic kinetics of the heterogeneous reaction were determined and analyzed. The results showed that the large-scale HPA had good thermal stability, and lower viscosity, gelling temperature and melting temperature compared with those of agar. The SEM indicated that the improvement of solubility of HPA was not only due to the hydrophilic effect of hydroxypropyl group, but also due to the formation of cluster structure and grid structure. The characteristic of heterogeneous hydroxypropylation reaction were determined by preliminary kinetic experiments, which demonstrated that the reaction order of propylene oxide was 2, while that for agar was approximately 0. The reaction activation energy of heterogeneous hydroxypropylation reaction was calculated to be 83.50 kJ/mol using the Arrhenius formula. Taken together, the results would provide guidances for the industrialization of hydroxypropyl agar.

Chemical characterization of a new sulfated polysaccharide from Gracilaria chouae and its activation effects on RAW264.7 macrophages

This study aimed to characterize the chemical composition of a new sulfated polysaccharide from the red alga Gracilaria chouae and evaluate its activation effects on RAW264.7 macrophages. It showed that the obtained G. chouae polysaccharide (GCP-3A) was a sulfated acidic polysaccharide with a molecular weight of 11.87 kDa. GCP-3A was composed of xylose, galactose, glucose, and mannose with a molar ratio of 3.00:29.28:0.63:0.45, and it contained α,β‍-glycosidic linkages. Scanning electron microscopy (SEM) and a Congo red test showed that it was a heterogeneous polysaccharide with irregular interwoven sheets and rods, and did not have a triple-helix conform‍ation. Furthermore, GCP-3A significantly promoted the proliferation of RAW264.7 macrophages and the secretion of nitric oxide (NO) in tests of 3-‍(4,‍5-dimethylthiahiazo-2-yl)‍-2,‍5-diphenytetrazoliumromide(MTT) and NO.

Bioactivity and composition of lipophilic metabolites extracted from Antarctic macroalgae

Macroalgae comprise a vast group of aquatic organisms known for their richness in phytochemicals. In this sense, the lipophilic profile of five Antarctic seaweed species was characterized by chromatographic and spectroscopic analysis and their antioxidant and antimicrobial potential was evaluated. Results showed there were 31 lipophilic substances, mainly fatty acids (48.73 ± 0.77 to 331.91 ± 10.79 mg.Kg-1), sterols (14.74 ± 0.74 to 321.25 ± 30.13 mg.Kg-1), and alcohols (13.07 ± 0.04 to 91.87 ± 30.07 mg.Kg-1). Moreover, Desmarestia confervoides had strong antioxidant activity, inhibiting 86.03 ± 1.47% of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical at 1 mg.mL-1. Antimicrobial evaluation showed that extracts from Ulva intestinalis, Curdiea racovitzae, and Adenocystis utricularis inhibited the growth of Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), and Salmonella typhimurium (ATCC 14028) from concentrations of 1.5 to 6 mg.mL-1. Therefore, the evaluated brown, red, and green macroalgae contained several phytochemicals with promising biological activities that could be applied in the pharmaceutical, biotechnological, and food industries.

Sustainable Sources from Aquatic Organisms for Cosmeceuticals Ingredients

Long life expectancy of populations in the developing world together with some cultural and social issues has driven the need to pay special attention to health and physical appearance. Cosmeceuticals are gaining interest in the cosmetic industry as their uses fulfills a double purpose: the requirements of a cosmetic (clean, perfume, protect, change the appearance of the external parts of the body or keeping them in good condition) with a particular bioactivity function. The cosmetics industry, producing both cosmetics and cosmeceuticals, is currently facing numerous challenges to satisfy different attitudes of consumers (vegetarianism, veganism, cultural or religious concerns, health or safety reasons, eco-friendly process, etc.). A currently growing trend in the market is the interest in products of low environmental impact. Marine origin ingredients are increasingly being incorporated into cosmeceutical preparations because they are able to address several consumer requirements and also due to the wide range of bioactivities they present (antioxidant, whitening, anti-aging, etc.). Many companies claim “Marine” as a distinctive marketing signal; however, only a few indicate whether they use sustainable ingredient sources. Sustainable marine ingredients might be obtained using wild marine biomass through a sustainable extractive fishing activity; by adopting valorization strategies including the use of fish discards and fish by-products; and by sustainably farming and culturing marine organisms.

Controlled sulfation of mixed-linkage glucan by Response Surface Methodology for the development of biologically applicable polysaccharides

Endogenous and exogenous sulfated polysaccharides exhibit potent biological activities, including inhibiting blood coagulation and protein interactions. Controlled chemical sulfation of alternative polysaccharides holds promise to overcome limited availability and heterogeneity of naturally sulfated polysaccharides. Here, we established reaction parameters for the controlled sulfation of the abundant cereal polysaccharide, mixed-linkage β(1,3)/β(1,4)-glucan (MLG), using Box-Behnken Design of Experiments (BBD) and Response Surface Methodology (RSM). The optimization of the degree-of-substitution (DS) was externally validated through the production of sulfated MLGs (S-MLGs) with observed DS and M_w values deviating less than 20% and 30% from the targeted values, respectively. Simultaneous optimization of DS and M_w resulted in the same range of deviation from the targeted value. S-MLGs with DS > 1 demonstrated a modest anticoagulation effect versus heparin, and a greater P-selectin affinity than fucoidan. As such, this work provides a route to medically important polymers from an economical agricultural polysaccharide.

Characterization of an Agarophyton chilense Oleoresin Containing PPARγ Natural Ligands with Insulin-Sensitizing Effects in a C57Bl/6J Mouse Model of Diet-Induced Obesity and Antioxidant Activity in Caenorhabditis elegans

The biomedical potential of the edible red seaweed Agarophyton chilense (formerly Gracilaria chilensis) has not been explored. Red seaweeds are enriched in polyunsaturated fatty acids and eicosanoids, which are known natural ligands of the PPARγ nuclear receptor. PPARγ is the molecular target of thiazolidinediones (TZDs), drugs used as insulin sensitizers to treat type 2 diabetes mellitus. Medical use of TZDs is limited due to undesired side effects, a problem that has triggered the search for selective PPARγ modulators (SPPARMs) without the TZD side effects. We produced Agarophyton chilense oleoresin (Gracilex®), which induces PPARγ activation without inducing adipocyte differentiation, similar to SPPARMs. In a diet-induced obesity model of male mice, we showed that treatment with Gracilex® improves insulin sensitivity by normalizing altered glucose and insulin parameters. Gracilex® is enriched in palmitic acid, arachidonic acid, oleic acid, and lipophilic antioxidants such as tocopherols and β-carotene. Accordingly, Gracilex® possesses antioxidant activity in vitro and increased antioxidant capacity in vivo in Caenorhabditis elegans. These findings support the idea that Gracilex® represents a good source of natural PPARγ ligands and antioxidants with the potential to mitigate metabolic disorders. Thus, its nutraceutical value in humans warrants further investigation.

New Insights on the Sporulation, Germination, and Nutritional Profile of Gracilaria gracilis (Rhodophyta) Grown under Controlled Conditions

The red seaweed Gracilaria gracilis is a widely cultivated species known for its high agar content. It is also an important source of proteins, minerals, and vitamins. The chemical profile of seaweed depends on the cultivation methods used and the growing conditions to which they are exposed. Thus, two independent methods of sporulation and germination were tested upon Gracilaria gracilis grown in controlled conditions. During the tests, different substrates, culture media and incubation times were tested to induce cystocarp maturation. The results showed that cystocarp maturation and spore release were successful, with a visible volume increase and format change in the protruding cystocarps. Furthermore, the process of maturation to germination was accomplished, fulfilling the complete life cycle. In parallel, the nutritional profile of the biomass obtained was evaluated and compared with the nutritional values of biomass collected from the environment. Results showed no significant differences between wild specimens and cultivated ones in organic matter, ash content, lipid content, carbohydrates, or phycocolloid content. The present work, therefore, presents two simple alternative methods with potential applications in start-ups aimed at the cultivation of seaweed. Through these methods, it is possible to obtain biomass with nutritional characteristics similar to those obtained in the wild.

Seasonal Changes in the Nutritional Composition of Agarophyton vermiculophyllum (Rhodophyta, Gracilariales) from the Center of Portugal

Seaweeds exhibit high nutritional value due to a balanced concentration of proteins, vitamins and minerals, a high concentration of low digestibility polysaccharides, and reduced levels of lipids, many of which are n-3 and n-6 fatty acids. The species Agarophyton vermiculophyllum is no exception and, as such, a comprehensive study of the chemical and nutritional profile of this red seaweed was carried out for 1 year. Seasonal variations in moisture, ash, protein and amino acids content, crude fibers, ascorbic acid, agar, lipids, and the corresponding fatty acid profile, were analyzed. We found low levels of fatty acids and a high protein content, but also noticed interesting seasonal change patterns in these compounds. The present study gives insights on the environmental conditions that can lead to changes in the nutritional composition of this species, aiming, therefore, to bring new conclusions about the manipulation of environmental conditions that allow for maximizing the nutritional value of this seaweed.

Antioxidant Potential of Physicochemically Characterized Gracilaria blodgettii Sulfated Polysaccharides

Marine rhodophyte polysaccharides have a wide range of described biological properties with nontoxic characteristics, and show great potential in prebiotics and the functional foods industries. However, there is a virtual lack of Gracilaria blodgettii polysaccharides (GBP) profiling and their bioactivities. This study was designed while keeping in view the lack of physical and chemical characterization of GBP. This polysaccharide was also not previously tested for any bioactivities. A linear random coil conformation was observed for GBP, which was found to be a polysaccharide. A significant sulfate (w/w, 9.16%) and 3,6-anhydrogalactose (AHG, w/w, 17.97%) content was found in GBP. The significant difference in its setting (27.33 °C) and melting (64.33 °C) points makes it resistant to increasing heat. This, in turn, points to its utility in industrial scale processing and in enhancing the shelf-life of products under high temperatures. A radical scavenging activity of 19.80%, 25.42% and 8.80% was noted for GBP (3 mg/mL) in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (ABTS) and hydroxyl radical (HO) scavenging assays, respectively. Therefore, the findings suggest that Gracilaria blodgettii polysaccharides display a good antioxidant potential and may have potential applications in the functional food industry.

Seaweed-Based Compounds and Products for Sustainable Protection against Plant Pathogens

Sustainable agricultural practices increasingly demand novel, environmentally friendly compounds which induce plant immunity against pathogens. Stimulating plant immunity using seaweed extracts is a highly viable strategy, as these formulations contain many bio-elicitors (phyco-elicitors) which can significantly boost natural plant immunity. Certain bioactive elicitors present in a multitude of extracts of seaweeds (both commercially available and bench-scale laboratory formulations) activate pathogen-associated molecular patterns (PAMPs) due to their structural similarity (i.e., analogous structure) with pathogen-derived molecules. This is achieved via the priming and/or elicitation of the defense responses of the induced systemic resistance (ISR) and systemic acquired resistance (SAR) pathways. Knowledge accumulated over the past few decades is reviewed here, aiming to explain why certain seaweed-derived bioactives have such tremendous potential to elicit plant defense responses with considerable economic significance, particularly with increasing biotic stress impacts due to climate change and the concomitant move to sustainable agriculture and away from synthetic chemistry and environmental damage. Various extracts of seaweeds display remarkably different modes of action(s) which can manipulate the plant defense responses when applied. This review focuses on both the similarities and differences amongst the modes of actions of several different seaweed extracts, as well as their individual components. Novel biotechnological approaches for the development of new commercial products for crop protection, in a sustainable manner, are also suggested.

Seaweeds Compounds: An Ecosustainable Source of Cosmetic Ingredients?

Seaweed-based cosmetics are being gradually used by consumers as a substitute of synthetic equivalent products. These seaweed-based products normally contain purified compounds or extracts with several compounds. Several seaweeds’ molecules already demonstrated a high potential as a cosmetic active ingredient (such as, mycosporine-like amino acids, fucoidan, pigments, phenolic compounds) or as a key element for the products consistency (agar, alginate, carrageenan). Moreover, seaweeds’ compounds present important qualities for cosmetic application, such as low cytotoxicity and low allergens content. However, seaweeds’ biochemical profile can be variable, and the extraction methods can cause the loss of some of the biomolecules. This review gives a general look at the seaweed cosmetics benefits and its current application in the cosmetic industry. Moreover, it focuses on the ecological and sustainable scope of seaweed exploitation to guarantee a safe source of ingredients for the cosmetic industry and consumers.

Cyanobacteria and Red Macroalgae as Potential Sources of Antioxidants and UV Radiation-Absorbing Compounds for Cosmeceutical Applications

In recent years, research on natural products has gained considerable attention, particularly in the cosmetic industry, which is looking for new bio-active and biodegradable molecules. In this study, cosmetic properties of cyanobacteria and red macroalgae were analyzed. The extractions were conducted in different solvents (water, ethanol and two combinations of water:ethanol). The main molecules with antioxidant and photoprotective capacity were mycosporine-like amino acids (MAAs), scytonemin and phenolic compounds. The highest contents of scytonemin (only present in cyanobacteria) were observed in Scytonema sp. (BEA 1603B) and Lyngbya sp. (BEA 1328B). The highest concentrations of MAAs were found in the red macroalgae Porphyra umbilicalis, Gelidium corneum and Osmundea pinnatifida and in the cyanobacterium Lyngbya sp. Scytonema sp. was the unique species that presented an MAA with maximum absorption in the UV-B band, being identified as mycosporine-glutaminol for the first time in this species. The highest content of polyphenols was observed in Scytonema sp. and P. umbilicalis. Water was the best extraction solvent for MAAs and phenols, whereas scytonemin was better extracted in a less polar solvent such as ethanol:_dH₂O (4:1). Cyanobacterium extracts presented higher antioxidant activity than those of red macroalgae. Positive correlations of antioxidant activity with different molecules, especially polyphenols, biliproteins and MAAs, were observed. Hydroethanolic extracts of some species incorporated in creams showed an increase in the photoprotection capacity in comparison with the base cream. Extracts of these organisms could be used as natural photoprotectors improving the diversity of sunscreens. The combination of different extracts enriched in scytonemin and MAAs could be useful to design broad-band natural UV-screen cosmeceutical products.

Optimization of Extraction Conditions for Gracilaria gracilis Extracts and Their Antioxidative Stability as Part of Microfiber Food Coating Additives

Incorporation of antioxidant agents in edible films and packages often relies in the usage of essential oils and other concentrated hydrophobic liquids, with reliable increases in antimicrobial and antioxidant activities of the overall composite, but with less desirable synthetic sources and extraction methods. Hydroethanolic extracts of commercially-available red macroalgae Gracilaria gracilis were evaluated for their antioxidant potential and phenolic content, as part of the selection of algal biomass for the enrichment of thermoplastic film coatings. The extracts were obtained through use of solid-liquid extractions, over which yield, DPPH radical reduction capacity, total phenolic content, and FRAP activity assays were measured. Solid-to-liquid ratio, extraction time, and ethanol percentages were selected as independent variables, and response surface methodology (RSM) was then used to estimate the effect of each extraction condition on the tested bioactivities. These extracts were electrospun into polypropylene films and the antioxidant activity of these coatings was measured. Similar bioactivities were measured for both 100% ethanolic and aqueous extracts, revealing high viability in the application of both for antioxidant coating purposes, though activity losses as a result of the electrospinning process were above 60% in all cases.

Seaweed Phenolics: From Extraction to Applications

Seaweeds have attracted high interest in recent years due to their chemical and bioactive properties to find new molecules with valuable applications for humankind. Phenolic compounds are the group of metabolites with the most structural variation and the highest content in seaweeds. The most researched seaweed polyphenol class is the phlorotannins, which are specifically synthesized by brown seaweeds, but there are other polyphenolic compounds, such as bromophenols, flavonoids, phenolic terpenoids, and mycosporine-like amino acids. The compounds already discovered and characterized demonstrate a full range of bioactivities and potential future applications in various industrial sectors. This review focuses on the extraction, purification, and future applications of seaweed phenolic compounds based on the bioactive properties described in the literature. It also intends to provide a comprehensive insight into the phenolic compounds in seaweed.

Algae Metabolites in Cosmeceutical: An Overview of Current Applications and Challenges

Cosmetics are widely used by people around the world to protect the skin from external stimuli. Consumer preference towards natural cosmetic products has increased as the synthetic cosmetic products caused adverse side effects and resulted in low absorption rate due to the chemicals' larger molecular size. The cosmetic industry uses the term "cosmeceutical", referring to a cosmetic product that is claimed to have medicinal or drug-like benefits. Marine algae have gained tremendous attention in cosmeceuticals. They are one of the richest marine resources considered safe and possessed negligible cytotoxicity effects on humans. Marine algae are rich in bioactive substances that have shown to exhibit strong benefits to the skin, particularly in overcoming rashes, pigmentation, aging, and cancer. The current review provides a detailed survey of the literature on cosmeceutical potentials and applications of algae as skin whitening, anti-aging, anticancer, antioxidant, anti-inflammation, and antimicrobial agents. The biological functions of algae and the underlying mechanisms of all these activities are included in this review. In addition, the challenges of using algae in cosmeceutical applications, such as the effectiveness of different extraction methods and processing, quality assurance, and regulations concerning extracts of algae in this sector were also discussed.

Chemical structure, anti-inflammatory and antinociceptive activities of a sulfated polysaccharide from Gracilaria intermedia algae

The present work aimed at carrying out the isolation and biochemical characterization of a sulfated polysaccharide fraction (PLS) from the marine algae Gracilaria intermedia and investigating its anti-inflammatory and antinociceptive potential. PLS was obtained through enzymatic digestion with papain and analyzed by means of gel permeation chromatography and Nuclear Magnetic Resonance to ¹H and ¹³C. In order to evaluate the potential of anti-inflammatory action of PLS, we performed paw edema induced by carrageenan, dextran, compound 48/80, histamine and serotonin. In addition, we also measured the concentration of myeloperoxidase, cytokines, the count of inflammatory cells and performed tests of the nociception. The PLS isolated was of high purity and free of contaminants such as proteins, and had molecular weight of 410 kDa. The same macromolecule was able to decrease the paw edema induced by all inflammatory agents (P < 0.05), myeloperoxidase (MPO) activity, neutrophil migration and IL-1β levels. It also decreased acetic acid-induced writhing (P < 0.05) and formalin-induced paw licking time (P < 0.05), but no in hot plate test. In summary, the PLS decreased the inflammatory response by reducing neutrophil migration and modulating IL-1β production and antinociceptive effects by a peripheral mechanism dependent on the down-modulation of the inflammatory mediators.

A Comprehensive Review of the Nutraceutical and Therapeutic Applications of Red Seaweeds (Rhodophyta)

The red seaweed group (Rhodophyta) is one of the phyla of macroalgae, among the groups Phaeophyceae and Chlorophyta, brown and green seaweeds, respectively. Nowadays, all groups of macroalgae are getting the attention of the scientific community due to the bioactive substances they produce. Several macroalgae products have exceptional properties with nutraceutical, pharmacological, and biomedical interest. The main compounds studied are the fatty acids, pigments, phenols, and polysaccharides. Polysaccharides are the most exploited molecules, which are already widely used in various industries and are, presently, entering into more advanced applications from the therapeutic point of view. The focuses of this review are the red seaweeds' compounds, its proprieties, and its uses. Moreover, this work discusses new possible applications of the compounds of the red seaweeds.

Quantitative and Qualitative HPLC Analysis of Mycosporine-Like Amino Acids Extracted in Distilled Water for Cosmetical Uses in Four Rhodophyta

Mycosporine-like amino acids (MAAs) have gained considerable attention as highly active photoprotective candidates for human sunscreens. However, more studies are necessary to evaluate the extraction efficiencies of these metabolites in cosmetic compatible solvents, as well as, their subsequent HPLC analysis. In the present study, MAA extraction using distilled water and 20% aqueous methanol in four Rhodophyta was investigated. Different re-dissolution solvents and a C8 and C18 columns were tested for the HPLC analysis. Porphyra-334, shinorine, palythine, palythine-serine, asterina-330, and palythinol were identified by HPLC/ESI-MS. The separation of these MAAs were improved employing the C8-column, and using methanol as re-dissolution solvent. Regarding total MAAs concentrations, no differences between the two solvents were found. The highest MAA amounts were observed injecting them directly in the HPLC. According to these results, distilled water could be an excellent extraction solvent for MAAs. Nevertheless, the re-dissolution in pure methanol after dryness would be the best option for the qualitative analysis of the most common MAAs in these red algae. Our results entail important implications regarding the use of red macroalgae as promising candidates as environment-friendly sources of natural sunscreens.

Effects of Seasonal Variability on the Physicochemical, Biochemical, and Nutritional Composition of Western Peninsular Malaysia Gracilaria manilaensis

This study evaluated the effect of seasonal variation on the physicochemical, biochemical, and nutritional composition of Gracilaria manilaensis. Sampling was designed during the main monsoon seasons in Malaysia-the Southwest monsoon (SWM) and Northeast monsoon (NEM)-to understand the intraspecific variation (p < 0.05). Carbohydrates, protein, and dietary fiber were found to be higher in NEM-G. manilaensis, whereas a higher ash content was quantified in SWM-G. manilaensis. No significant differences were found in crude lipid and moisture content (p > 0.05). Vitamin B2 was calculated as (0.29 ± 0.06 mg 100 g-1) and (0.38 ± 0.06 mg 100 g-1) for the NEM and SWM samples, respectively (p < 0.05). The fatty acid profile showed the dominance of saturated fatty acids (SFAs)-palmitic acids, stearic acid, and myristic acid-while the mineral contents were found to be good sources of calcium (1750.97-4047.74 mg 100 g-1) and iron (1512.55-1346.05 mg 100 g-1). Tryptophan and lysine were recorded as the limiting essential amino acids (EAAs) in NEM G. manilaensis, while leucine and phenylalanine were found to be the limiting EAAs in the SWM samples. None of the extracts exhibited antibacterial properties against the screened strains. The study concluded that seasonal changes have a great effect on the biochemical composition of G. manilaensis.

Biochemical, Micronutrient and Physicochemical Properties of the Dried Red Seaweeds Gracilaria edulis and Gracilaria corticata

The present study sought to evaluate the nutritional composition and physicochemical properties of two dried commercially interesting edible red seaweeds, Gracilaria corticata and G. edulis. Proximate composition of the dried seaweeds revealed a higher content in carbohydrates (8.30 g/100 g), total crude protein (22.84 g/100 g) and lipid content (7.07 g/100 g) in G. corticata than in G. edulis. Fatty acids profile showed that G. corticata samples contain higher concentrations of saturated fatty acids, such as palmitic and stearic acids, and polyunsaturated ones such as α-linolenic and docosahexaenoic acids. Contrariwise, G. edulis contained higher amounts of monounsaturated oleic acid. Total amino acid content was 76.60 mg/g in G. corticata and 65.42 mg/g in G. edulis, being the essential amino acid content higher in G. edulis (35.55 mg/g) than in G. corticata (22.76 mg/g). Chlorophyll a was found in significantly higher amounts in G. edulis (17.14 μg/g) than G. corticata, whereas carotenoid content was significantly higher in G. corticata (12.98 μg/g) than in G. edulis. With respect to physical properties, both water- and oil-holding capacities were similar in both seaweeds, whereas swelling capacity was higher in G. edulis. In view of the results, the present study suggests that G. corticata and G. edulis contains important nutrients for human health and are possible natural functional foods.