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Microwave-assisted hydrothermal processing was proposed to recover high valuable compounds with antioxidant and gelling features from Ulva spp. green seaweed. The influence of the extraction conditions on the solubles, ulvan fraction and residual solid phase was studied to achieve a global valorization of the seaweed. A particular emphasis was placed on the selective coagulation of ulvan stimulated by a bio-ionic liquid during the extraction process. The achieved outcomes indicated that the selected microwave treatment exhibited a notable impact on the phytochemical properties of the soluble extracts, with the highest values of sulfate and protein content at 160 °C, and the highest antioxidant features at 200 °C. The most prominent molecular weight distributions were also identified for systems hydrothermal treated at 160 °C. The ulvan analyses showed that those extracted after microwave treatment at 160 °C showed the highest yields, molecular weight and the strongest gel features from the rheological point of view. The presence of the chloride chlorine during the extraction process favored the ulvan performance and the enhancement of the corresponding viscoelastic properties. [ABSTRACT FROM AUTHOR]

Ulvan, a sulfated polysaccharide extracted from Ulva spp., has garnered significant attention in the food and pharmaceutical industries due to its potential health benefits. These include immunomodulation, antiviral, anti-inflammatory, anti-hyperlipidemic, and anti-cancer effects. Nonetheless, practical applications in these fields remain limited due to an incomplete understanding of its gelation mechanisms. Additionally, the underlying mechanisms of its gelation have not been completely understood and thoroughly reviewed. The primary objective is to provide current insights into ulvan's gelling mechanisms and potential health impacts. This review also delves into the existing applications of ulvan polysaccharides. By unraveling these aspects, the information provided in this work is expected to deepen our understanding of ulvan's gelation mechanisms and its prospective role in enhancing health, holding promise for advancements in the fields of food science and disease prevention. This work's theoretical insights contribute significantly to a deeper understanding of these aspects, which holds paramount importance in unleashing the full potential of ulvan and elevating its scientific significance. • Ulvan holds potential as a gelling agent offering therapeutic effects. • Gelling and therapeutic effects of ulvan are influenced by its sulfate groups. • Ulvan's molecular weight and structure affect its health-promoting properties • Ulvan solutions can present both shear-thinning and shear-thickening behaviors. [ABSTRACT FROM AUTHOR]

Ulvans from Ulva ohnoi , Ulva tepida and Ulva prolifera were extracted under mild acidic conditions, isolated and their composition and structure determined. The ulvans contained mostly rhamnose (31.6–46.7 mol%) and glucuronic acid (26.6–37.5 mol%), with smaller amounts of xylose (3.4–10.4 mol%) and iduronic acid (3.1–7.6 mol%). In addition, the ulvan samples also contained galactose (4.4–26.0 mol%). Glycosyl linkage analysis showed that ulvan from U. ohnoi contained mostly →4)-Glc p A-(1→ and →3,4)-Rha p -(1→. Preparation of partially methylated alditol acetate standards of idose showed that U. ohnoi contained →4)-Ido p A-(1→. In addition to these residues, glycosyl linkage analysis of U. tepida and U. prolifera showed the presence of →2,3,4)-Rha p -(1→, →4)-Xyl p -(1→, →2,4)-Glc p A-(1→ and →3,4)-Glc p A-(1→. These two species also contained galactose linkages. These data, together with nuclear magnetic resonance (NMR) spectroscopy indicated that U. ohnoi comprised mostly of type A 3S ulvanobiuronic acid repeats [→4)- β - D -Glc p A-(1→4)- α - L -Rha p 3S-(1→], together with smaller amounts of type B 3S ulvanobiuronic acid repeats [→4)- α - L -Ido p A-(1→4)- α - L -Rha p 3S-(1→] and ulvanobiose (U 3S [→4)- β - D -Xyl p -(1→4)- α - L -Rha p 3S-(1→]). NMR spectra of U. tepida and U. prolifera showed resonances not detected in U. ohnoi , highlighting the complexity of the ulvans from these species. Regardless of the structural diversity of the ulvan samples there was very little antioxidant or inhibitory activity detected on enzymatic processes investigated. • Ulvans were extracted from three Ulva species using mild conditions. • The structure of the ulvans was determined by GC–MS and NMR spectroscopy. • Ulva ohnoi contained mostly type A 3S and B 3S ulvanobiuronic acid disaccharide units. • Ulva tepida and Ulva prolifera contained linkages characteristic of branching. [ABSTRACT FROM AUTHOR]

Polysaccharides derived from seaweeds can be used as biostimulants to enhance plant resistance to different stressors. In this study, we investigated the effects of applying low molecular weight polysaccharides (LPU) derived from Ulva prolifera with 14.2 kDa on the responses of wheat (Triticum aestivum) to osmotic stress. The results showed that osmotic stress simulated using polyethylene glycol inhibited seedling growth, whereas we observed increases in the fresh weights and shoot lengths of seedlings treated with polysaccharide for 120 h. Furthermore, we observed enhanced activities of antioxidant enzymes, and significant reductions in malondialdehyde content of 23.13%, 19.82%, and 20.04% in response treatment for 120 h with 0.01%, 0.03%, and 0.05% LPU, respectively, relative to those in the group treated with polyethylene glycol alone. In all treatments, expression of the P5CS gene was upregulated to promote proline accumulation. Moreover, after 120 h, exogenously applied LPU induced the expression of stress-related genes, including SnRK2 , Wabi5 , Wrab18 , and Wdhn13. Collectively, these findings indicate that LPU might have the effect of regulating the abscisic acid-dependent pathway in wheat, thereby increasing seedling antioxidant capacity and growth. Application of LPU may accordingly represent an effective approach for enhancing the resistance to osmotic stress in wheat. [ABSTRACT FROM AUTHOR]

In this study, flash extraction was used to rapidly extract water-soluble polysaccharides from Ulva linza. The optimal extraction process for the flash extraction was determined by Box–Behnken design with extraction temperature 80 °C, extraction time 117 s, liquid-solid ratio 46:1 (mL/g) and a corresponding yield of 18.5 %. The crude Ulva linza polysaccharides (CULP) were subsequently isolated by chromatography technology to obtain purified Ulva linza polysaccharide (ULP) and characterized by monosaccharide composition and molecular weight determination analysis. Furthermore, the antioxidant bioactivity of ULP was studied and the results revealed that it had a good scavenging effect on DPPH, ABTS and OH, with IC 50 values of 149.2 μg/mL, 252.5 μg/mL and 1073 μg/mL, respectively. After in vitro fermentation by human fecal microbiota, the pH value of fermentation culture significantly decreased to 5.06, suggesting that ULP could be hydrolyzed and utilized by gut microbiota. The abundance of beneficial bacteria including Bacteroides , Parabacteroides and Faecalibacterium was improved. Meanwhile, the relative abundance of Prevotella , Blautia and Ruminococcus was decreased, and the low ratio of these organisms might reveal positive effects on maintaining the balance of gut microbial biodiversity. These results suggested that the composition of the human gut microbiota could be modulated by ULP, and ULP might possess the potential to maintain gut homeostasis and improve human intestinal health. • Flash extraction was employed for rapid extraction of ulvan from U. linza. • ULP was isolated from U. linza extraction with an average M w value of 474 kDa. • ULP revealed stable after the simulated upper gastrointestinal digestion. • ULP has the potential for maintaining gut homeostasis and intestinal health. [ABSTRACT FROM AUTHOR]

As a biocompatible polymer, ulvan has applications in countless fields. Therefore, the following study intends to extract ulvan from Ulva fasciata , emphasizing its use for biomedical and industrial applications in the manufacture of nanofibrous webs. The extracted ulvan was characterized using FT-IR, DSC, XRD, GPC, and NMR. The extracted ulvan's FT-IR spectra confirmed that it is a sulfated polysaccharide. The HPLC analysis showed that the extracted ulvan is composed of rhamnose, xylose, glucose and glucuronic acid. NMR showed that the proton chemical shifts at 1.3 are due to methyl protons of rhamnose 3-sulfate in the ulvan samples. The X-ray diffractograms suggested that the extracted ulvan is semi-crystalline polymer with major crystalline reflection at 2θ of 29.4°. Deionized water has been successfully used to produce ulvan/polyvinyl alcohol (ulvan/PVA) nanofibers as an eco-friendly solvent. It was found that the ulvan-to-PVA (1:2) ratio results in nanofiber that is well handled and smooth. In addition to pretreated ones, the ulvan extracted without organic solvent pretreatment showed bead free nanofibers. It is concluded that pretreatment with organic solvent in ulvan extraction, particularly in the manufacture of nanofibers, is not recommended. In addition, the resulting nanofibrous mat has sufficient mechanical properties for various applications to be incorporated. [ABSTRACT FROM AUTHOR]

An alcohol-induced liver injury model was induced in C57BL/6 mice to assess the protective efficacy of Enteromorpha prolifera polysaccharides (EP) against liver damage. Histological alterations in the liver were examined following hematoxylin-eosin (H&E) staining. Biochemical assay kits and ELISA kits were employed to analyze serum and liver biochemical parameters, as well as the activity of antioxidant enzymes and alcohol metabolism-related enzymes. The presence of oxidative stress-related proteins in the liver was detected using western blotting. Liquid chromatography and mass spectrometry were used to profile serum metabolites in mice. The findings demonstrated that EP-H (100 mg/Kg) reduced serum ALT and AST activity by 2.31-fold and 2.32-fold, respectively, when compared to the alcohol-induced liver injury group. H&E staining revealed a significant attenuation of microvesicular steatosis and ballooning pathology in the EP-H group compared to the model group. EP administration was found to enhance alcohol metabolism by regulating metabolite-related enzymes (ADH and ALDH) and decreasing CYP2E1 expression. EP also modulated the Nrf2/HO-1 signaling pathway to bolster hepatic antioxidant capacity. Furthermore, EP restored the levels of lipid metabolites (Glycine, Butanoyl-CoA, and Acetyl-CoA) to normalcy. In summary, EP confers protection to the liver through the regulation of antioxidant activity and lipid metabolites in the murine liver., Competing Interests: Declaration of competing interest All authors have read the declaration of interests and declare that they have no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study investigates conformational aspects of ulvans (F2) and their polycarboxyl derivatives obtained through periodate–chlorite oxidation (C3) followed by DEAE-Sephacel fractioning (C3b and C3c). Size exclusion chromatography coupled with laser light scattering and viscometric detection, in addition to circular dichroism (CD) and molecular modeling analyses, suggested that F2 had a compact sphere conformation with a helical motif as secondary structure. In contrast, all the polycarboxyl ulvans showed a random coil conformation, although C3c (NaSO 3 − 21.0%; COO− 1.81 mmol·g−1; M w 18 kg·mol−1) had a more rigid and constrained backbone than C3 (NaSO 3 − 21.0%; COO− 1.81 mmol·g−1; M w 49 kg·mol−1), largely due to its higher sulfate and carboxyl content. Despite the higher ionic character of C3c , its anticoagulant activity (ACA), determined by activated partial thromboplastin time (APTT) assay, was not improved compared to that of C3. Moreover, C3b (NaSO 3 − 14.1%; COO− 1.23 mmol·g−1; M w 8.1 kg·mol−1) had higher activity than F2 (NaSO 3 − 20.6.%; COO− 0.36 mmol·g−1; M w 123 kg·mol−1), even with its lower sulfate content and molar mass. These results suggest that the ACA of polycarboxyl ulvans relies on carboxyl and sulfate content and may depend, in addition, on a proper flexible conformation. Unlabelled Image [ABSTRACT FROM AUTHOR]

Marine green algae are valuable sources of diverse health-promoting bioactive components. Ulvan is suitable for biological applications due to its unique structure and numerous bioactivities. Here, the complex structure of ulvan from Ulva pertusa was analyzed using specific ulvan lyase degradation, MS, and NMR detection. Its structure mainly consists of →4)-β- d -GlcA-(1 → 4)-α- l -Rha3S-(1 → and →4)-β- d -Xyl-(1 → 4)-α- l -Rha3S-(1 → repeating units. Small amounts of →4)-α- l -IdoA-(1 → 4)-α- l -Rha3S-(1 → unit also exist. In addition, a minor number of branches, a single GlcA, and a long branch containing GlcA-Glc were linked to Rha3S. The antiviral activity of the ulvan and its degraded fragments were further investigated. Ulvan (1068.2 kDa) and ulvan-F1 (38.5 kDa) with relatively high molecular weight showed potency of inhibiting the infection and replication of vesicular stomatitis virus (VSV) at 100 μg/mL, the inhibition rate of VSV replication was 40.75% and 40.13%, respectively. These results indicated that ulvan has potential as a functional agent. • An ulvan lyase was used for the structure analysis of ulvan-F0 from Ulva pertusa. • Ulvan-F0 consists of three repeating disaccharide units and two side branches. • Molecular weight significantly affects the antiviral activity of ulvan. • Ulvan-F0 and ulvan-F1 (38.5 kDa) could inhibit the infection and replication of VSV. [ABSTRACT FROM AUTHOR]

A new approach of algal-polymer -sheets was performed by the embedding of two algal seaweeds (Ulva fasciata and Sargassum dentifolium) into cellulose acetate (CA) polymer forming two types of cellulose acetate; Ulva (CA-U) and Sargassum (CA-S) sheets. Afterward, the two sheets were characterized then subjected to 3-Rs evaluation (Removal, Recovery, and Reuse) of methylene blue dye (MB). Characterization data exhibited good properties for biosorption process. Algal biosorbents achieved more than twice biosorption capacity (Q max) after the embedding into the polymer sheet. Additionally, according to factorial design data, the contact time and the dose of biosorbents had positive effects on the biosorption in the two sheets. Freundlich, Langmuir, and pseudo-second order models displayed good represented data in the two sheets. Furthermore, the two sheets (CA-U, followed by CA-S sheet) were successfully given more than 98% adsorption of 273 mg/l MB concentration. Moreover, the recovery and reuse data proved that the two sheets can be performed in good behavior for more than three cycles. Unlabelled Image [ABSTRACT FROM AUTHOR]

In this study, purification of polysaccharide ulvan by anion exchange chromatography was prepared, and the major polysaccharide fraction (FU) was collected at 1.0 M NaCl elute by anion exchange chromatography, then high sulfate content purified ulvan (HFU) was prepared with sulfur trioxide/ N , N -dimethylformamide (SO 3 -DMF) in formamide. The antioxidant activity and the antihyperlipidemic activity of HFU in mice were determined. The results showed that treatment with HFU could improve the antioxidant and antihyperlipidemic activity. Compared with the hyperlipidemic group, the antihyperlipidemic activity of HFU (125 mg/kg) was the strongest, TC concentrations were significantly decreased by 26.7% (P <.01), significantly reduced LDL-C (32.6%, P <.01), significantly increased HDL-C (19.6%, P <.01), and HFU-treated group (250 mg/kg) exhibited optimal effects on TG (29.0%, P <.01); the HFU groups at the doses of 125 mg/kg could significantly decrease the MDA (29.9%, P <.01); the HFU groups at the doses of 500 mg/kg could increase the activities of GSH-Px obviously (19.9%, P <.01). • The high sulfate content purification ulvan (HFU) was prepared successfully and the sulfate content was 28.1%. • The antioxidant activity of HFU exhibited stronger activity than U and FU. • The antihyperlipidemic activity of HFU was stronger than U and FU, especially at the dose of 125 mg/kg. [ABSTRACT FROM AUTHOR]

• The phosphorylated ulvan (PU) was prepared by mixed phosphate method. • The PU was chemically phosphated to reach 10.47% of phosphate content. • This experiment combined with P% and 31P NMR results to prove the successful preparation of PU. • The antioxidant experiments in vivo , PU exhibited stronger activity than U, the best in CAT activity. • The antihyperlipidemic activity of PU was stronger than U. Ulvan was the polysaccharide (U) from a large edible green algae Ulva pertusa. In this study, phosphorylated ulvan (PU) was prepared by the sodium trimetaphosphate -sodium tripolyphosphate method. Antioxidant and antihyperlipidemic effects of U and PU were investigated employing in vivo systems. The PU was confirmed by IR, 31P NMR and 13C NMR spectra. And in addition, we found that the PU3 group at the dose of 500 mg/kg showed stronger antioxidant activity. Compared with hyperlipidemia group, it significantly increased GSH-Px (34.29%; P < 0.01), SOD (20.04%; P < 0.01) and CAT (37.49%; P < 0.01). Treatment of hyperlipidemia mice with PU resulted in a significant decrease in TC, TG and LDL-C, and significant increase in HDL-C. The PU3 significantly increased HDL-C (33.70%; P < 0.01), decreased LDL-C (52.73%; P < 0.01) and TG (33.58%; P < 0.01) compared with hyperlipidemia group. The result showed that phosphorylation could improve hypolipidaemic and antioxidant activities in vivo. PU may be used as a drug for hyperlipidaemia treatment. [ABSTRACT FROM AUTHOR]

Oligosaccharides from green algae Ulva lactuca (ULO) and Enteromorpha prolifera (EPO) were used for investigation of anti-ageing effects and the underlying mechanism in SAMP8 mice. The structural properties of ULO and EPO were analyzed by fourier-transform infrared spectroscopy, gas chromatography–mass spectrometry, and agarose gel electrophoresis. These oligosaccharides enhanced the glutathione, superoxide dismutase, catalase, and telomerase levels and total antioxidant capicity, and decreased the levels of malondialdehyde and advanced glycation end products. After ULO and EPO treatment, the levels of inflammatory factors, including IFN-γ, TNF-α, and IL-6, decreased; the BDNF and ChAT levels increased; and hippocampal neurons were protected. Downregulation of the p53 and FOXO1 genes and upregulation of the Sirt1 gene indicated that ULO and EPO have potential therapeutic effects in the prevention of ageing in SAMP8 mice. By 16S rRNA gene high-throughput sequencing, the abundance of Desulfovibrio was discovered to be markedly different in mice treated with ULO and EPO. The abundances of Verrucomicrobiaceae , Odoribacteraceae , Mogibacteriaceae , Planococcaceae , and Coriobacteriaceae were positively correlated with age-related indicators. These results demonstrated that oligosaccharides from U. lactuca and E. prolifera are ideal candidate compounds that can be used in functional foods and pharmaceuticals to prevent ageing. Unlabelled Image • First report on anti-ageing of U. lactuca and E. prolifera oligosaccharides on SAMP8 • Analysis of gut microbiota composition in ageing by 16S rRNA gene sequencing • Relation of gut microbiota and ageing-related indicators were evaluated by R Stuodio [ABSTRACT FROM AUTHOR]

Finding green effective methods for dye removal from wastewater created an important interest in comparison to conventional methods. The aim of the present work was directed to study micro grinded dried biomass of two macro-algal species, Ulva fasciata and Sargassum dentifolium as complementary biosorbent materials for effective methylene blue (MB) removal from waste water. The two macro-algal species were collected, dried, and grinded by ball mill to get the micro size. After that, the biosorbent materials were characterized by FT-IR, TEM, and DLS. Furthermore, Full Factorial Design was applied to determine the optimum conditions that maximize the MB adsorption efficiency. Ulva fasciata biosorbent material was achieved the highest MB adsorption capacity, 97% of 328 mg/l MB with a maximum adsorption capacity (q max) of 244 mg/g in comparison to the Sargassum dentifolium , 85.6% of 26 mg/l MB with (q max) of 66.6 mg/g. Based on Factorial Design data the main effects of the Ulva biosorbent exhibited that both time & biosorbent dose had a positive effect on biosorption and both pH & MB concentrations have a negative effect, on the other hand, no temperature effect on both biosorbents. Point of zero charge (pH pzc) was recorded at pH 6.7 and 9 for Ulva and Sargassum biosorbents, respectively. The obtained results suggested that the two macro-algal species can be used in a complementary consecutive process where Ulva fasciata started first and followed by Sargassum dentifolium. The complementary treatment process achieved efficiency of 99.2% adsorption of 300 mg/l MB concentration. Moreover, the kinetic data suggested that the adsorption of MB follows the pseudo-second order model. [ABSTRACT FROM AUTHOR]

A water-soluble polysaccharide was isolated from marine green algae Ulva pertusa and then chelated with iron to prepare the polysaccharide‑iron (III) complex. The immunomodulatory activities of sulfated polysaccharide and polysaccharide‑iron (III) complex were investigated through a mice immune-deficiency model. Cyclophosphamide (Cy) was utilized to establish mice immunodeficiency model. Both polysaccharide and polysaccharide‑iron (III) complex were proved to promote the proliferation of lymphocyte and enhance the activities of mice macrophages. In mice serum, the levels of cytokines including TNF-α, IFN-γ and IL-10 restored and the contents of hemolysin were also found elevated after treatment with polysaccharide and its iron complex. Besides, it has been shown that both polysaccharide and polysaccharide‑iron (III) complex increased the contents of Hb, RBC and HCT in mice blood, and the effect of iron complex was better. All these results suggested that Ulva pertusa polysaccharide could be developed as a healthy function food. It was also noteworthy that the polysaccharide‑iron (III) complex showed no negative effect upon the immunomodulatory activity of polysaccharide. Instead, the polysaccharide‑iron (III) complex showed excellent hematopoietic capacity perhaps due to the supplement of iron. [ABSTRACT FROM AUTHOR]

Rapid accumulations of unattached green macroalgae, referred to as blooms, constitute ecological disasters and occur in many coastal regions. Ulva are a major cause of blooms, owing to their high nitrogen utilization capacity, which requires nitrate reductase (NR) activity; however, molecular characterization of Ulva NR remains lacking. Herein we determined the crystal structure and performed an enzymatic analysis of the cytochrome b 5 reductase domain of Ulva prolifera NR ( Up CbRNR). The structural analysis revealed an N-terminal FAD-binding domain primarily consisting of six antiparallel β strands, a C-terminal NADH-binding domain forming a Rossmann fold, and a three β-stranded linker region connecting these two domains. The FAD cofactor was located in the cleft between the two domains and interacted primarily with the FAD-binding domain. Up CbRNR shares similarities in overall structure and cofactor interactions with homologs, and its catalytic ability is comparable to that of higher plant CbRNRs. Structure and sequence comparisons of homologs revealed two regions of sequence length variation potentially useful for phylogenetic analysis: one in the FAD-binding domain, specific to U. prolifera , and another in the linker region that may be used to differentiate between plant, fungi, and animal homologs. Our data will facilitate molecular-level understanding of nitrate assimilation in Ulva . [ABSTRACT FROM AUTHOR]

The aim of this research was to investigate the effect of metallic ions (Na + , Ca 2+ , K + and Mg 2+ ) on the physicochemical stability of curcumin emulsions stabilized by Ulva fasciata polysaccharide (UFP). Mean droplet diameter, PdI, zeta-potential, microscopic morphology, and rheological properties of curcumin emulsion stabilized by UFP were investigated. The results showed that different metal ions had significantly different effects on the stability of emulsion. When the effect of Mg 2+ was compared with others, it was found that Mg 2+ had a pronounced effect on emulsion stability. As for z-average size and PdI, they changed significantly for metallic ions with higher valence. According to the rheology test, Ca 2+ could mediate the gelation of UFP emulsions. Besides, with an increase of ionic concentration, the retention rate of curcumin was reduced. In comparison with gum Arabic, the UFP revealed better stability under different metallic ions and ionic concentration at same concentration. [ABSTRACT FROM AUTHOR]

The aim of the present study was to examine how factors (pH, temperature, iron chelators, and free radical scavengers) influence on the chemical stabilities of β-carotene encapsulated by Ulva fasciata polysaccharide (UFP)-stabilized emulsions and the bioaccessibility under in vitro oral-gastro-intestinal digestion conditions. The concentration of β-carotene in emulsions under different environments was determined. Changes in droplet properties, particle size and microstructure, throughout the oral-gastric-intestinal model were measured and the rate and extent of lipid digestion were recorded in the simulated small intestine fluid. Our results suggested that the pH had a significant effect on the stability of β-carotene, a rapid degradation at acidic environment and a relatively higher stability at high pH (6.0 and 7.0) were observed. β-carotene in emulsions was highly sensitive to extreme temperature (80 °C, 90 °C, and 100 °C). Addition of EDTA or α-tocopherol significantly increased the stability of β-carotene. Meanwhile, digested UFP-stabilized emulsions showed higher lipid digestion rate than GA-stabilized emulsions and BP-stabilized emulsions. UFP was capable of increasing the bioaccessibility of β-carotene in emulsions compared to GA and BP. Therefore, UFP-stabilized emulsion is a promising delivery system to promote applications of β-carotene in functional food and beverage system. [ABSTRACT FROM AUTHOR]

Ulva prolifera macroalgae blooming caused by water eutrophication seriously affects the marine ecological environment. Exploring an efficient approach to turning algae biomass waste into high-value-added products is significant. The present work aimed to demonstrate the feasibility of the bioactive polysaccharide extraction from Ulva prolifera and to evaluate its potential biomedical application. A short autoclave process was proposed and optimized using the response surface methodology to extract Ulva polysaccharides (UP) with high molar mass. Our results indicated that UP with high molar mass (9.17 × 105 g/mol) and competitive radical scavenging activity (up to 53.4 %) could be effectively extracted with the assistance of Na 2 CO 3 (1.3 %, wt.) at a solid-liquid ratio of 1/10 in 26 min. The obtained UP mainly composes of galactose (9.4 %), glucose (73.1 %), xylose (9.6 %), and mannose (4.7 %). The biocompatibility of the UP and its potential application as a bioactive ingredient in 3D cell culture has been evaluated and confirmed by confocal laser scanning microscopy and fluorescence microscope imaging inspection. This work demonstrated the feasibility of extracting bioactive sulfated polysaccharides with potential applications in biomedicine from biomass waste. Meanwhile, this work also provided an alternative solution to deal with the environmental challenges incurred by algae blooming worldwide. [ABSTRACT FROM AUTHOR]

This study investigates chitosan coating containing nanoliposome of Ulva intestinalis sulfated polysaccharide, its effect on melanosis, as well as the quality of Pacific white shrimp during 20 days of storage in ice. The sulfated polysaccharide was extracted from Ulva intestinalis (USP), and its impact on the shrimp's polyphenol oxidase (PPO) enzyme inhibition in different concentrations was measured. The optimum concentration of USP with the highest inhibition percentage was selected and used. USPs were loaded in nanoliposome or coated in chitosan then shrimps were immersed in these coatings. 1.5 % USP showed the highest inhibitory effect of PPO enzyme after 1 and 3 min with values of 63.03 % and 48.74 %. The melanosis of shrimps with different types of USP coating was significantly lower than the control. The lowest color change (ΔE), total viable counts (TVC) bacterial, TVN content, and weight loss were achieved in the Ch-USP treatment. The highest sensory score was found in the Ch-N-USP treatment. This coverage delayed the increase of psychrophilic bacteria (PBC) and chemical tests (TBA, FFA, and PV). Therefore, Ch-USP and Ch-N-USP treatments can be used as a natural substitute for sodium metabisulfite to increase the shelf life and shrimp quality during ice storage. • Sulfated polysaccharide from Ulva intestinalis (USP) showed a relatively good inhibitory effect on the PPO enzyme of shrimp. • The melanosis score in the Ch-USP treatment was significantly lower than the control. • USP in chitosan coating controlled the color change (ΔE), bacterial tests, and TVN content of shrimp. • The Ch-N-USP-treated shrimp showed the best results in chemical tests (TBA, FFA, and PV) and the highest sensory score. [ABSTRACT FROM AUTHOR]

The structure of an ulvan obtained by water extraction from green seaweed Ulva lactuca was elucidated by using IR, NMR, SEC-MALL and ESIMS methods. The ulvan was also evaluated for its cytotoxic effects on three human cancer cell lines. The results showed that the ulvan was composed of rhamnose, galactose, xylose, manose, glucose (with a mole ratio of Rha: Gal: Xyl: Man: Glu equal to 1: 0.03: 0.07: 0.01: 0.06), uronic acid (21.5%) and sulfate content (18.9%) with a molecular weight of 347000. This ulvan mainly consists of disaccharide [→4)-β- d -GlcA-(1 → 4)-α- l - R ha3 S -(1→] and other minor disaccharide β-GlcA-(1 → 2)-α-Xyl and β-GlcA-(→2)-α-Rha. The ulvan showed a significant cytotoxic activity against hepatocellular carcinoma (IC 50 29.67 ± 2.87 μg/ml), human breast cancer (IC 50 25.09 ± 1.36 μg/ml), and cervical cancer (IC 50 36.33 ± 3.84 μg/ml). [ABSTRACT FROM AUTHOR]

Ulva prolifera can protect human skin fibroblast from being injured by hydrogen peroxide. This work studied the composition of Ulva prolifera polysaccharide and identified its physicochemical properties. The results showed that the cell proliferation of 0.5 mg/mL crude polysaccharide was 154.4% of that in negative control group. Moreover, ROS detection indices, including DCFH-DA, GSH-PX, MDA and CAT, indicated that crude polysaccharide could improve cellular ability to scavenge free radical and decrease the injury on human skin fibroblast by hydrogen peroxide. In purified polysaccharide, the activity of fraction P1-1 was the highest, with 174.6% of that in negative control group. The average molecular weight of P1-1 was 137 kD with 18.0% of sulfate content. This work showed the inhibition of hydrogen peroxide induced injuries on human skin fibroblast by Ulva prolifera polysaccharide, which may further evaluate the application of U. prolifera on cosmetics. [ABSTRACT FROM AUTHOR]

The biochemical characteristics and immunomodulatory activity of sulphated polysaccharides isolated from Ulva intestinalis and fractionated using a silica-silica column were investigated. The unfractionated (USP) and fractionated sulphated polysaccharides (FSP4, FSP30, and FSP32) consisted mostly of carbohydrates (4.84–26.55%) and sulphates (2.85–20.42%). Structural analyses showed that USP, FSP4, FSP30 and FSP32 had molecular weights of 300, 80, 110 and 140 kDa, respectively. FSP30 exhibited the strongest DPPH radical scavenging activity. Moreover, FSP30 showed stronger immunomodulatory activities than UPS in term of stimulating the production of pro-inflammatory cytokines, including nitric oxide (NO), tumour necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), in macrophage J774A.1 cells. USP and FSP30 were not cytotoxic to mouse macrophage at the tested concentrations (6.25–50 μg/mL). The results suggested that U. intestinalis polysaccharides could be explored as potential antioxidant and immunomodulatory agents to be used as complementary medicine or functional foods. [ABSTRACT FROM AUTHOR]

Ulva intestinalis , a tubular green seaweed, is a rich source of nutrient, especially sulphated polysaccharides. Sulphated polysaccharides from U. intestinalis were extracted with distilled water, 0.1 N HCl, and 0.1 N NaOH at 80 °C for 1, 3, 6, 12, and 24 h to study the effect of the extraction solvent and time on their chemical composition and antioxidant activity. Different types of solvents and extraction time had a significant influence on the chemical characteristics and antioxidant activity ( p < 0.05). Monosaccharide composition and FT-IR spectra analyses revealed that sulphated polysaccharides from all solvent extractions have a typical sugar backbone (glucose, rhamnose, and sulphate attached at C-2 or C-3 of rhamnose). Sulphated polysaccharides extracted with acid exhibited greater antioxidant activity than did those extracted with distilled water and alkali. The results indicated that solvent extraction could be an efficacious method for enhancing antioxidant activity by distinct molecular weight and chemical characteristic of sulphated polysaccharides. [ABSTRACT FROM AUTHOR]

Sulfated polysaccharide (UFP 31 ) extracted from the marine algae Ulva fasciata (UFP) was a heteropolysaccharide, and consisted of rhamnose, xylose, and glucose in a ratio of 1:0.46:0.27 with a (1 → 4)-linked glycosyl backbone. The rheology of UFP 31 solution has been investigated by steady shear and small amplitude oscillatory experiments. The effects of concentration, temperature, and time were systematically investigated. Steady-shear rheological measurement in a range of shear rate (1–1000s −1 ) exhibited that UFP 31 has a Newtonian behavior in diluted solutions (1.0%, 3.0%, and 5.0%, w/v), dilatant flow behavior at higher concentrations (7.0% and 9.0%, w/v). Specifically, UFP 31 solution (7%, w/v) exhibited antithixotropic behavior. In small amplitude oscillatory experiments, both the storage modulus (G′) and the loss modulus (G”) of UFP 31 solution (7%, w/v) increased with frequency swept but G′ increased more quickly. As a consequence, G′ tends to overcome G” at 2.7 Hz. The capability of moisture-absorption and moisture-retention of the polysaccharide was also respectively examined gravimetrically in comparison with those of glycerol. It revealed that UFP 31 exhibited a higher ability both in the moisture-absorption and moisture-retention test throughout the entire experiment. These results clearly establish the possibility that UFP 31 could be employed as a new material of nature moisturizer. [ABSTRACT FROM AUTHOR]

Abstract: Ulva fasciata belonging to the family Ulvaceae, commonly known as ‘sea lettuce’, is an abundantly growing green seaweed in coastal seashore of South China. Three different molecular weight sulfated polysaccharides (UFP1, UFP2 and UFP3) were extracted and separated from U. fasciata by hot water extraction and ultrafiltration. The three native UFP fractions had partial desulfurization by solvolytic desulfation respectively and the effect of sulfate content on the exhibition of the antioxidant and anti-tumor capacities had been evaluated and compared. The results showed that each native polysaccharide (UFP1, UFP2, UFP3) with high sulfate content exhibited better antioxidant activities compared with the partial desulfated polysaccharides (DS-UFP1, DS-UFP2, DS-UFP3). Specifically, UFP2 with relatively high sulfate content, molecular weight and uronic acid content had consistently excellent antioxidant performances. However, UFP2 demonstrated the minimal inhibitory effects on growth of DLD intestinal cancer cells. Instead, DS-UFP3 with the lowest sulfate content but highest uronic acid content and molecular weight exhibited the best antitumor activity. [Copyright &y& Elsevier]

Abstract: Polysaccharides with different molecular weights were extracted from Ulva pertusa and fractionated by ultrafiltration. Iron(III) complex of the low molecular-weight U. pertusa polysaccharides were synthesized. Atomic absorption spectrum showed that the iron content of iron(III)–polysaccharide complex was 27.4%. The comparison between U. pertusa polysaccharides and their iron(III) complex showed that iron chelating altered the structural characteristics of the polysaccharides. The bioactivity analysis showed that polysaccharide with low molecular weight was more effective than polysaccharide with high molecular weight in protecting mice from radiation induced damages on bone marrow cells and immune system. Results also proved that the anti-radiation and anti-oxidative activity of iron(III) complex of low molecular-weight polysaccharides were not less than that of low molecular-weight polysaccharides. [Copyright &y& Elsevier]

Abstract: Four different molecular weight sulfated polysaccharides (UFP1, UFP2, UFP3 and UFP4) were extracted and separated from Ulva fasciata by hot water extraction and ultrafiltration. Their chemical and physical characteristics were determined and antioxidant activities were investigated on the basis of superoxide radical assay, hydroxyl radical assay, ABTS radical assay, and reducing power assay. The results showed that four polysaccharides exhibited antioxidant properties, and UFP2 and UFP3, which have lower content of sulfate showed higher antioxidant activities than UFP1 and UFP4, which have higher content of sulfate. Besides, the content of protein, uronic acid and molecular weights of polysaccharides also influence their antioxidant activities. The antioxidant activities of UFP were not a function of a single factor but a combination of several factors. [Copyright &y& Elsevier]

In this study, we discussed the relationship between Entermorpha linza polysaccharide (EP) and Bacillus subtilis, which can transform nitrate. A sole carbon source experiment showed that Bacillus subtilis could utilize EP, and the bacterial density was maximally increased by 54.43% in the EP groups. The results of reducing sugar determination proved the secretion of polysaccharide-degrading enzymes. Scanning electron microscopy (SEM) showed that the EP groups had fewer spores and shrunken bacteria, indicating that EP could improve the growth environment and maintain bacterial integrity. Additionally, the ratios of periplasmic nitrate reductase (NAP), nitrite reductase (NIR), and dissimilatory nitrate reductase (D-NRase) in the EP groups were maximally increased by 107.22%, 84.70% and 36.10%, respectively. Transcriptome analysis further confirmed the above mentioned results. For example, the high expression of quorum sensing genes indicated that EP groups had higher bacterial density. Moreover, the high expression of antioxidant genes in the EP groups may be related to morphological integrity. Our study provides a basis for further discussion of the mechanism., (Copyright © 2022 Elsevier B.V. All rights reserved.)