Investigation into the Phytochemical Composition, Antioxidant Properties, and In-Vitro Anti-Diabetic Efficacy of Ulva lactuca Extracts.

In this research, the chemical compositions of various extracts obtained from Ulva lactuca, a type of green seaweed collected from the Nador lagoon in the northern region of Morocco, were compared. Their antioxidant and anti-diabetic properties were also studied. Using GC-MS technology, the fatty acid content of the samples was analyzed, revealing that palmitic acid, eicosenoic acid, and linoleic acid were the most abundant unsaturated fatty acids present in all samples. The HPLC analysis indicated that sinapic acid, naringin, rutin, quercetin, cinnamic acid, salicylic acid, apigenin, flavone, and flavanone were the most prevalent phenolic compounds. The aqueous extract obtained by maceration showed high levels of polyphenols and flavonoids, with values of 379.67 ± 0.09 mg GAE/g and 212.11 ± 0.11 mg QE/g, respectively. This extract also exhibited an impressive ability to scavenge DPPH radicals, as indicated by its IC50 value of 0.095 ± 0.12 mg/mL. Additionally, the methanolic extract obtained using the Soxhlet method demonstrated antioxidant properties by preventing ß-carotene discoloration, with an IC50 of 0.087 ± 0.14 mg/mL. Results from in-vitro studies showed that extracts from U. lactuca were able to significantly inhibit the enzymatic activity of α-amylase and α-glucosidase. Among the various extracts, methanolic extract (S) has been identified as the most potent inhibitor, exhibiting a statistically similar effect to that of acarbose. Furthermore, molecular docking models were used to evaluate the interaction between the primary phytochemicals found in these extracts and the human pancreatic α-amylase and α-glucosidase enzymes. These findings suggest that U. lactuca extracts contain bioactive substances that are capable of reducing enzyme activity more effectively than the commercially available drug, acarbose.

Potentials of Ulva spp.-derived sulfated polysaccharides as gelling agents with promising therapeutic effects.

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.

Effective capping of dissolved sulfide generated in Ulva prolifera-rich marine sediments by iron-rich red soil.

Bloom-induced macroalgal enrichment on the seafloor can substantially facilitate dissolved sulfide (DS) production through sulfate reduction. The reaction of DS with sedimentary reactive iron (Fe) is the main mechanism of DS consumption, which however usually could not effectively prevent DS accumulation caused by pulsed macroalgal enrichment. Here we used incubations to investigate the performance of Fe-rich red soil for buffering of DS produced from macroalgae (Ulva prolifera)-enriched sediment. Based on our results, a combination of red soil additions (6.8 kg/m2) before and immediately after pulsed macroalgal deposition (455 g/m2) can effectively cap DS within the red soil layer. The effective DS buffering is mainly due to ample Fe-oxide surface sites available for reaction with DS. Only a small loss (4 %) of buffering capacity after 18-d incubation suggests that the red soil is capable of prolonged DS buffering in macroalgae-enriched sediments.

Bioaccessibility of toxic heavy metals/metalloids in edible seaweeds: Exposure and health risk assessment.

This study assesses the health risk due to heavy metals/metalloids (HMs/Ms) in edible seaweeds (Caulerpa racemosa, Kappaphycus alvarezii, and Ulva lactuca) through an in vitro bioaccessibility study. The percentage of bioabsorbed HMs/Ms in unprocessed and processed C. racemosa, U. lactuca, and K. alvarezii ranged from 3 % to 46 %, 3 % to 42 %, and 3 % to 40 %, respectively. The levels of HMs/Ms in seawater, sediment, and seaweeds were below the levels recommended by the European Commission (EC) and World Health Organization/Food and Agriculture Organization (WHO/FAO). The maximum accumulation of HMs/Ms was found during monsoons and post-monsoon seasons, and Cd, Pb, Hg, Cr, As, and Pb were predominant in all the samples. Tukey's post hoc test and t-test confirmed that thermal processing significantly reduced HMs/Ms in seaweeds. On the basis of the bioabsorption of HMs/Ms, the TTHQ values were found to be < 1, and the LCR values were within the acceptable limit (10-06 to 10-04), indicating no carcinogenic risks through seaweeds.

Composition and nutritional values of fatty acids in marine organisms by one-step microwave-assisted extraction/derivatization and comprehensive two-dimensional gas chromatography -flame ionization detector.

This work reports the characterization of the lipidic fraction of seven species of marine organisms gathered along the shoreline of the Po Delta Park of Emilia-Romagna Region (Italy) and of the north Adriatic Sea. Two species of oysters (Crassostrea gigas and Ostrea edulis), two species of clams (Chamelea gallina and Ruditapes philippinarum), one species of mussel (Mytilus galloprovincialis), one species of macroalgae (Ulva rigida), and one species of spiny dogfish (Squalus acanthias) were analyzed to characterize their fatty acids profile and related nutritional value. The lipid fraction was simultaneously extracted and transesterified into fatty acid methyl esters (FAMEs) by using a recently developed one-step microwave-assisted extraction/derivatization (MAED) method. The obtained FAMEs extract was analyzed by a rapid comprehensive multidimensional gas chromatography (GC × GC) method (30 min). The system was equipped with a reverse set of columns (polar × non-polar) connected through a reversed fill/flush flow modulator. The GC × GC system was coupled with a flame-ionization detector (FID) for both qualitative and quantitative purposes. The MAED- GC × GC-FID methodology was suitable in the context of samples containing high percentages of omega-3 PUFA. A total of 82 FAMEs were tentatively identified using standards, literature data, and the two-dimensional plot location. FAME profiles obtained with the proposed approach were comparable with reference methods (AOCS Ce 2b-11), showing no significant differences. Moreover, to determine the food nutritional value of the samples investigated, the most common nutritional indices (index of atherogenicity, index thrombogenicity, hypocholesterolemic/hypercholesterolemic ratio, health-promoting index, unsaturation index, and the fish lipid quality index) were calculated from FAME profiles. Among the samples investigated, Squalus acanthias presented the best nutritional score, while Ruditapes philippinarum had the worst score in 3 out of 6 indices.

Characterization and Biological Activities of the Ulvan Polysaccharide-Rich Fraction Obtained from Ulva rigida and Ulva pseudorotundata and Their Potential for Pharmaceutical Application.

Seaweed from the genus Ulva (Ulvales, Chlorophyta) has a worldwide distribution and represents a potential biomass source for biotechnological applications. In the present study, we investigated the ulvan polysaccharide-rich fraction (UPRF) isolated from two Ulva species (U. rigida and U. pseudorotundata), naturally occurring on the Spanish Mediterranean coast. Chemical characterization of UPRFs was performed in order to explore the polysaccharides' composition. Biological assessments of UPRFs were compared by antioxidant activity and in vitro toxicity tests in the human cell lines: HCT-116 (colon cancer), G-361 (malignant melanoma), U-937 (leukemia), and HaCaT cells (immortalized keratinocytes). Chemical analysis revealed that both UPRFs presented rhamnose as the major relative sugar constituent, followed by glucose in U. rigida and xylose in U. pseudorotundata. Both also presented glucuronic acid, galactose, ribose, and mannose as the remaining monosaccharides. Similar antioxidant activity was obtained, where we observed increased activity in response to increased polysaccharide concentrations. Both UPRFs presented moderate toxicity against HCT-116 cell lines and a selectivity index ≥ 3, suggesting a good potential for use in pharmaceutical products.

Fabrication of carbon black nanoparticles from green algae and sugarcane bagasse.

There are several industrial uses for carbon black (CB), an extremely fine powdered form of elemental carbon that is made up of coalesced particle aggregates and almost spherical colloidal particles. Most carbon black is produced from petroleum-derived feedstock, so there is a need to find an alternative method to produce CB, which relies on renewable resources such as algae and agricultural waste. A process involving hydrolysis, carbonization, and pyrolysis of green algae and sugarcane bagasse was developed, as the optimal hydrolysis conditions (16N sulfuric acid, 70 °C, 1 h, 1:30 g/ml GA or SC to sulfuric acid ratio), a hydrolysis ratio of 62% for SC and 85% for GA were achieved. The acidic solution was carbonized using a water bath, and the solid carbon was then further pyrolyzed at 900 °C. The obtained carbon black has a high carbon content of about 90% which is confirmed by EDX, XRD, and XPS analysis. By comparison carbon black from sugar cane bagasse (CBB) and carbon black from green algae Ulva lactuca (CBG) with commercial carbon black (CCB) it showed the same morphology which was confirmed by SEM analysis. The BET data, showed the high specific surface area of prepared CB, which was 605 (m2/g) for CBB and 424 (m2/g) for CBG compared with commercial carbon black (CBB) was 50 (m2/g), also the mean pore diameter of CBB, CBG and CCB indicated that CBB and CBG were rich in micropores, but CCB was rich in mesoporous according to IUPAC classification. This study might have created a technique that can be used to make carbon black from different kinds of biomass.

Acclimation of intertidal macroalgae Ulva prolifera to UVB radiation: the important role of alternative oxidase.

BACKGROUND: Solar radiation is primarily composed of ultraviolet radiation (UVR, 200 - 400 nm) and photosynthetically active radiation (PAR, 400 - 700 nm). Ultraviolet-B (UVB) radiation accounts for only a small proportion of sunlight, and it is the primary cause of plant photodamage. The use of chlorofluorocarbons (CFCs) as refrigerants caused serious ozone depletion in the 1980s, and this had led to an increase in UVB. Although CFC emissions have significantly decreased in recent years, UVB radiation still remains at a high intensity. UVB radiation increase is an important factor that influences plant physiological processes. Ulva prolifera, a type of macroalga found in the intertidal zone, is intermittently exposed to UVB. Alternative oxidase (AOX) plays an important role in plants under stresses. This research examines the changes in AOX activity and the relationships among AOX, photosynthesis, and reactive oxygen species (ROS) homeostasis in U. prolifera under changes in UVB and photosynthetically active radiation (PAR). RESULTS: UVB was the main component of solar radiation impacting the typical intertidal green macroalgae U. prolifera. AOX was found to be important during the process of photosynthesis optimization of U. prolifera due to a synergistic effect with non-photochemical quenching (NPQ) under UVB radiation. AOX and glycolate oxidase (GO) worked together to achieve NADPH homeostasis to achieve photosynthesis optimization under changes in PAR + UVB. The synergism of AOX with superoxide dismutase (SOD) and catalase (CAT) was important during the process of ROS homeostasis under PAR + UVB. CONCLUSIONS: AOX plays an important role in the process of photosynthesis optimization and ROS homeostasis in U. prolifera under UVB radiation. This study provides further insights into the response of intertidal macroalgae to solar light changes.

A metabolomic snapshot through NMR revealed differences in phase transition during the induction of reproduction in Ulva ohnoi (Chlorophyta).

The present study deals with the metabolomic status of Ulva cells undergoing phase transition (vegetative, determination and differentiation) when exposed to different abiotic conditions. The objective was to study whether metabolite changes occurring during the phase transition reveal any commonality among differential abiotic conditions. The phase transition was followed through microscopic observations and 1H NMR characterization at 0 h, 24 h, and 48 h after the incubation of the thallus under abiotic conditions, such as different salinities (20-35 psu), temperatures (20-35 °C), photoperiods (18 : 6, 12 : 12, and 6 : 18 D/N), light intensities (220, 350, and 500 µmol photons m-2 s-1), nitrate (0.05-0.2 g L-1) and phosphate (0.05-0.2 g L-1) concentrations. Microscopic analysis revealed the role of all abiotic conditions except variable salinity and phosphate concentration in phase transition. NMR analysis revealed that glucose increased in the determination phase [7.58 to 9.62 normalized intensity (AU)] and differentiation phase (5.85 to 6.41 AU) from 20 °C to 25 °C temperature. Coniferyl aldehyde increased in vegetative (5.79 to 6.83 AU) and differentiation (6.66 to 7.40 AU) phases from 20 °C to 30 °C temperature. The highest average (22.97) was found in photoperiod (average range = 0-122.91) and the highest SD (24.73) in salinity (SD range = 1.86-57.04) in region 9 (creatinine and cysteine) of the differentiation phase. A total of 30 metabolites were identified under the categories of sugars, amino acids, and aromatic compounds. The present study will aid in understanding the mechanisms underlying cell differentiation during reproduction. The result may serve as an important reference point for future studies, besides helping in controlling seedling preparation for commercial farming as well as the management of rapid green tide formation.

Structural Analysis and Novel Mechanism of Enteromorpha prolifera Sulfated Polysaccharide in Preventing Type 2 Diabetes Mellitus.

A water-soluble polysaccharide (EP) was purified from edible algae Enteromorpha prolifera. Gel permeation chromatography (GPC), ion chromatography (IC), and fourier transform infrared (FT-IR) were performed to characterize its structure. EP was defined as a low molecular weight (6625 Da) composed of rhamnose, glucose, glucuronic acid, xylose, galactose, arabinose, and mannose. Moreover, it was a sulfated polysaccharide with a degree of substitution (DS) of 1.48. Then, the high-fat diet/streptozotocin (HFD/STZ) induced diabetic mouse model was established to support evidence for a novel hypoglycemic mechanism. Results showed that blood glucose (47.32%), liver index (7.65%), epididymal fat index (16.86%), serum total cholesterol (26.78%) and triglyceride (37.61%) in the high-dose EP (HEP) group were significantly lower than those in the HFD group. Noticeably, the content of liver glycogen in the HEP group was significantly higher (62.62%) than that in the HFD group, indicating the promotion of glycogen synthesis. These beneficial effects were attributed to significantly increased protein kinase B (AKT) phosphorylation and its downstream signaling response. Further studies showed that diabetic mice exhibited excessive O-GlcNAcylation level and high expression of O-linked ß-D-N-acetylglucosamine transferase (OGT), which were decreased by 62.21 and 30.43% in the HEP group. This result suggested that EP had a similar effect to OGT inhibitors, which restored AKT phosphorylation and prevented pathoglycemia. This work reveals a novel hypoglycemic mechanism of EP, providing a theoretical basis for further studies on its pharmacological properties in improvement of T2DM.

Enteromorpha Prolifera Polysaccharide-Derived Injectable Hydrogel for Fast Intraoperative Hemostasis and Accelerated Postsurgical Wound Healing Following Tumor Resection.

Intraoperative bleeding and delayed postsurgical wound healing caused by persistent inflammation can increase the risk of tumor recurrence after surgical resection. To address these issues, Enteromorpha prolifera polysaccharide (PEP) with intrinsic potentials for hemostasis and wound healing, is chemically modified into aldehyde-PEP and hydrazine-PEP. Thereby, an injectable double-network hydrogel (OPAB) is developed via forming dual dynamic bonding of acylhydrazone bonds between the decorated aldehyde and hydrazine groups and hydrogen bonds between hydroxyl groups between boric acid and PEP skeletons. The OPAB exhibits controllable shape-adaptive gelation (35.0 s), suitable mechanical properties, nonstimulating self-healing (60 s), good wet tissue adhesion (30.9 kPa), and pH-responsive biodegradability. For in vivo models, owing to these properties, OPAB can achieve rapid hemostasis within 30 s for the liver hemorrhage, and readily loading of curcumin nanoparticles to remarkably accelerate surgical wound closure by alleviating inflammation, re-epithelialization, granulation tissue formation, and collagen deposition. Overall, this multifunctional injectable hydrogel is a promising material that facilitates simultaneous intraoperative hemorrhage and postsurgical wound repair, holding significant potential in the clinical managements of bleeding and surgical wounds for tumor resection.

Structural Characterization and Cytotoxic Activity Evaluation of Ulvan Polysaccharides Extracted from the Green Algae Ulva papenfussii.

Ulvan, a sulfated heteropolysaccharide with structural and functional properties of interest for various uses, was extracted from the green seaweed Ulva papenfussii. U. papenfussii is an unexplored Ulva species found in the South China Sea along the central coast of Vietnam. Based on dry weight, the ulvan yield was ~15% (w/w) and the ulvan had a sulfate content of 13.4 wt%. The compositional constitution encompassed L-Rhamnose (Rhap), D-Xylose (Xylp), D-Glucuronic acid (GlcAp), L-Iduronic acid (IdoAp), D-Galactose (Galp), and D-Glucose (Glcp) with a molar ratio of 1:0.19:0.35:0.52:0.05:0.11, respectively. The structure of ulvan was determined using High-Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), and Nuclear Magnetic Resonance spectroscopy (NMR) methods. The results showed that the extracted ulvan comprised a mixture of two different structural forms, namely ("A3s") with the repeating disaccharide [→4)-ß-D-GlcAp-(1→4)-α-L-Rhap 3S-(1→]n, and ("B3s") with the repeating disaccharide [→4)-α-L-IdoAp-(1→4)-α-L-Rhap 3S(1→]n. The relative abundance of A3s, and B3s was 1:1.5, respectively. The potential anticarcinogenic attributes of ulvan were evaluated against a trilogy of human cancer cell lineages. Concomitantly, Quantitative Structure-Activity Relationship (QSAR) modeling was also conducted to predict potential adverse reactions stemming from pharmacological interactions. The ulvan showed significant antitumor growth activity against hepatocellular carcinoma (IC50 ≈ 90 µg/mL), human breast cancer cells (IC50 ≈ 85 µg/mL), and cervical cancer cells (IC50 ≈ 67 µg/mL). The QSAR models demonstrated acceptable predictive power, and seven toxicity indications confirmed the safety of ulvan, warranting its candidacy for further in vivo testing and applications as a biologically active pharmaceutical source for human disease treatment.

Analysis of Volatile Constituent by Hydrodistillation and Solid-Phase Microextraction Techniques and Antimicrobial and Scolicidal Activities of Essential Oil and Soxhlet Extracts of Ulva rigida grown in Turkey.

In the present study, the volatile composition of Ulva rigida (U. rigida) was elucidated by two different methods. As a result of the identification process of volatile components using the GC/MS-FID instrument, 31 compounds were identified by hydrodistillation (HD) method, and 15 compounds were identified by solid-phase microextraction (SPME) method, elucidating the structure of 99.86 % and 92.65 %, respectively. The most abundant compounds in the essential oil of U. rigida were n-hexadecanoic acid and pentadecanal, while the most abundant compound according to the SPME analysis was heptadecyne, a hydrocarbon compound. In the next step, hexane, dichloromethane, chloroform and methanol solvent extracts of U. rigida were prepared and the antimicrobial activities of the extracts and the essential oil obtained by hydro-distillation as well as the scolicidal activities of the solvent extracts were determined. The results of the antimicrobial activity test of the essential oil showed a high level of activity against Bacillus cereus ATCC 10876 and MRSA. The highest activity was found on the microorganism of Pseudomonas aeruginosa ATCC 9027 in chloroform and methanol extracts of U. rigida. Furthermore, viability detection was performed and the scolicidal effects of the extracts on protoscoleces were assessed. The values of lethal concentration doses (LD50 , LD75 and LD90 ) were calculated using probit analysis.

Biohydrogen production through energy efficient surfactant induced microwave pretreatment of macroalgae Ulva reticulata.

Macroalgal biomass being rich in carbohydrates, proteins and lipids in their cell wall has been considered as the most efficient organic rich sources for biofuel (biohydrogen) production. In this study, Pluronic P-123-induced microwave pretreatment was applied to disintegrate the marine macroalgae biomass, Ulva reticulata. Microwave disintegration was done by varying the treatment time and microwave power from 0 to 40 min and 0.09 KW to 0.63 KW. A maximum chemical oxygen demand (COD) solubilization of 22.33% was achieved at a microwave power and time duration of 0.36 kW and 15 min. Chemical (Pluronic P-123, a mild surfactant) was combined with optimum microwave disintegration conditions to increase the solubilization efficiency and this combined pretreatment achieved a maximum COD solubilization of 31.02% at 10 min pretreatment time and 0.06 g per g TS of Pluronic P-123 dosage. The present study indicated that combination of surfactant with microwave pretreatment substantially improves the COD solubilization with reduced pretreatment -time than mono microwave pretreatment. An optimal hydrogen yield of 98.37 mL was achieved through this combined pretreatment. The biohydrogen data was modelled with Gompertz model and the kinetic parameters derived through this model implies that the calculated adjusted R squared values for all the samples lies between 0.95 and 0.99. This shows that the model fitted biohydrogen experimental values accurately. In addition, Pluronic P-123-induced microwave pretreatment was regarded as energy efficient and cost effective than microwave pretreatment alone with net energy production and a greater energy ratio of 504.38 kWh/Ton macroalgae and 1.2 when compared to microwave pretreatment alone (-2975.6 kWh/Ton macroalgae and 0.5).

Chemical Composition and Antioxidant Potential of Five Algae Cultivated in Fully Controlled Closed Systems.

In this study, the chemical composition and antioxidant profile of five edible macroalgae, Fucus vesiculosus, Palmaria palmata, Porphyra dioica, Ulva rigida, and Gracilaria gracilis, cultivated in fully controlled closed systems, were determined. Protein, carbohydrates, and fat contents ranged between 12.4% and 41.8%, 27.6% and 42.0%, and 0.1% and 3.4%, respectively. The tested seaweeds presented considerable amounts of Ca, Mg, K, Mn, and Fe, which reinforce their favorable nutritional profile. Regarding their polysaccharide composition, Gracilaria gracilis and Porphyra dioica were rich in sugars common to agar-producing red algae, and Fucus vesiculosus was composed mainly of uronic acids, mannose, and fucose, characteristic of alginate and fucoidans, whereas rhamnose and uronic acid, characteristic of ulvans, predominated in Ulva rigida. Comparatively, the brown F. vesiculosus clearly stood out, presenting a high polysaccharide content rich in fucoidans, and higher total phenolic content and antioxidant scavenging activity, determined by DPPH and ABTS. The remarkable potential of these marine macroalgae makes them excellent ingredients for a wide range of health, food, and industrial applications.

The preventive effects of Ulva lactuca aqueous extract, ulvan polysaccharides and atorvastatin on ethylene glycol-induced hyperoxaluria.

OBJECTIVE: Kidney stones are a common complication of hyperoxaluria. The aim of this study is to investigate the protective and preventive effects of Ulva lactuca aqueous extract, ulvan polysaccharides and atorvastatin on ethylene glycol-induced hyperoxaluria. MATERIALS AND METHODS: Male Wistar rats between 110 and 145 g in weight were used in the study, Ulva lactuca aqueous extract and polysaccharides were prepared. The male albino rats were supplemented with 0.75 percent ethylene glycol (v/v) in their drinking water for six weeks to induce hyperoxaluria. Ulvan infusions (100 mg/kg body weight), ulvan polysaccharides (100 mg/kg body weight), and atorvastatin (two milligrams/kg body weight) to treat hyperoxaluric rats for four weeks (every other day) were used. Weight loss, serum creatinine, serum urea, serum uric acid, serum oxalate, kidney oxalate, kidney lipid peroxidation, and kidney DNA fragmentation and kidney histopathological studies were done. RESULTS: Weight loss, rise of serum creatinine, serum urea, serum uric acid, serum oxalate, kidney oxalate, kidney lipid peroxidation, and kidney DNA fragmentation were all shown to be prevented by the addition of atorvastatin, polysaccharides, or aqueous extract, respectively. Catalase (CAT) activity, glutathione peroxidase (GPX) activity, glutathione-S-transferase (GST) activity, and histopathological perturbations were all significantly reduced by the medicines that were studied. CONCLUSIONS: Hyperoxaluria caused by ethylene glycol may be prevented by a combination of Ulva lactuca aqueous extract, ulvan polysaccharides, and atorvastatin. A reduction in renal oxidative stress and an improvement of the antioxidant defense system may be responsible for these protective benefits. However, Ulva lactuca infusion and ulvan polysaccharides need to be studied further in humans, in order to determine their efficacy and safety.

Suppression of hepatocellular carcinoma by Ulva lactuca ulvan via gut microbiota and metabolite interactions.

INTRODUCTION: Ulva lactuca polysaccharide (ULP) is green algae extract with numerous biological activities, including anticoagulant, anti-inflammatory, and antiviral effects. However, the inhibitory ability of ULP in the development of hepatocellular carcinoma warrants further studies. OBJECTIVES: To elucidate the anti-tumor mechanism of ULP action and evaluate its regulatory effect on gut microbiota and metabolism in H22 hepatocellular carcinoma tumor-bearing mice. METHODS: An H22 tumor-bearing mouse model was established by subcutaneously injecting H22 hepatoma cells. The gut microbiota composition in cecal feces was assessed and subjected to untargeted metabolomic sequencing. The antitumor activity of ULP was verified further by western blot, RT-qPCR, and reactive oxygen species (ROS) assays. RESULTS: Administration of ULP alleviated tumor growth by modulating the compositions of the gut microbial communities (Tenericutes, Agathobacter, Ruminiclostridium, Parabacteroides, Lactobacillus, and Holdemania) and metabolites (docosahexaenoic acid, uric acid, N-Oleoyl Dopamine, and L-Kynurenine). Mechanistically, ULP promoted ROS production by inhibiting the protein levels of JNK, c-JUN, PI3K, Akt, and Bcl-6, thereby delaying the growth of HepG2 cells. CONCLUSION: ULP attenuates tumor growth in H22 tumor-bearing mice by modulating gut microbial composition and metabolism. ULP inhibits tumor growth mainly by promoting ROS generation.

Effect of chitosan-coated Ulva intestinalis sulfated polysaccharide nanoliposome on melanosis and quality of Pacific white shrimp during ice storage.

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.

Application of polysaccharide-rich solution derived from waste macroalgae Enteromorpha prolifera in cherry tomato preservation and utilizing post-extraction residue for crude bio-oil production.

Preservative is of importance to retard fruit deterioration and prolong the shelf-life. The suitability of using water-soluble polysaccharide extracted from waste macroalgae Enteromorpha prolifera (EPP) for cherry tomato preservation was evaluated. As compared with the control, the EPP-treated cherry tomatoes exhibited better fruit appearance, lower disease index and rot index during storage. Around 47 % EPP-treated cherry tomatoes were commercially acceptable after 36 days, which was however only 15.6 % for untreated cherry tomatoes, indicating the satisfactory preservation effectiveness of EPP-rich solution for cherry tomatoes. The post-extraction residue was commonly underutilized, we herein attempted to employ an emerging thermochemical conversion technique, hydrothermal liquefaction, to produce crude bio-oil (biocrude) from post-extraction E. prolifera. A biocrude yield of ∼23 wt% (dry-ash-free, daf) was obtained, and fatty acids and phenolics were identified to be the two main components in biocrude. The biocrude contained ∼70 % carbon and the higher heating value was ∼30 MJ/kg.

Purification identification and function analysis of ACE inhibitory peptide from Ulva prolifera protein.

In the present study, Ulva prolifera, an edible alga, was used to prepare angiotensin-I converting enzyme (ACE) inhibitory peptide. The algae protein was isolated and later hydrolyzed by five commercial enzymes (alcalase, papain, pepsin, trypsin, neutral protease), either individually or in combination. Hydrolysate, with the highest in vitro ACE inhibitory activity, was processed using the Sephadex-G100, ultrafiltration, HPLC-Q-TOF-MS, ADMET screening and molecular docking, respectively. The ACE inhibitory peptide DIGGL with a IC50 value of 10.32 ± 0.96 µM was then identified. The peptide against ACE by a non-competitive mode and mainly attributable to the three Conventional Hydrogen Bonds. It could activate Endothelial nitric oxide synthase activity in NO generation and reduce Endothelin-1 secretion induced by Angiotensin II in Human umbilical vein endothelial cells. Meanwhile, DIGGL could promote mice splenocytes proliferation, which was also effective when co-incubated with Con A or LPS, respectively. Besides, the anti-ACE peptide could remain active during the digestion of gastrointestinal proteases (pepsin-trypsin) in vitro.