Highly crystalline cellulose microparticles from dealginated seaweed waste ameliorate high fat-sugar diet-induced hyperlipidemia in mice by modulating gut microbiota.

The effects of seaweed cellulose (SC) on high fat-sugar diet (HFSD)-induced glucolipid metabolism disorders in mice and potential mechanisms were investigated. SC was isolated from dealginated residues of giant kelp (Macrocystis pyrifera), with a crystallinity index of 85.51 % and an average particle size of 678.2 nm. Administering SC to C57BL/6 mice at 250 or 500 mg/kg BW/day via intragastric gavage for six weeks apparently inhibited the development of HFSD-induced obesity, dyslipidemia, insulin resistance, oxidative stress and liver damage. Notably, SC intervention partially restored the structure and composition of the gut microbiota altered by the HFSD, substantially lowering the Firmicutes to Bacteroidetes ratio, and greatly increasing the relative abundance of Lactobacillus, Bifidobacterium, Oscillospira, Bacteroides and Akkermansia, which contributed to improved short-chain fatty acid (SCFA) production. Supplementing with a higher dose of SC led to more significant increases in total SCFA (67.57 %), acetate (64.56 %), propionate (73.52 %) and butyrate (66.23 %) concentrations in the rectal contents of HFSD-fed mice. The results indicated that highly crystalline SC microparticles could modulate gut microbiota dysbiosis and ameliorate HFSD-induced obesity and related metabolic syndrome in mice. Furthermore, particle size might have crucial impact on the prebiotic effects of cellulose as insoluble dietary fiber.

Sodium alginate and chitosan co-modified fucoxanthin liposomes: preparation, bioaccessibility and antioxidant activity.

To improve the stability of fucoxanthin, fucoxanthin liposomes (L) were prepared by the thin-film ultrasound method, and fucoxanthin liposomes were modified with sodium alginate and chitosan by an electrostatic deposition method. The release characteristics of fucoxanthin in different types of liposomes with in vitro gastrointestinal simulation were studied. Under the optimum conditions, the results showed that the encapsulation efficiency of prepared liposomes could reach 88.56 ± 1.40% (m/m), with an average particle size of 295.27 ± 7.28 nm, a Zeta potential of -21.53 ± 2.00 mV, a polydispersity index (PDI) of 0.323 ± 0.007 and a loading capacity of 33.3 ± 0.03% (m/m). Compared with L and chitosan modified fucoxanthin liposomes (CH), sodium alginate and chitosan modified fucoxanthin liposomes (SA-CH) exhibited higher storage stability, in vitro bioaccessibility and antioxidant activity after gastrointestinal digestion. Sodium alginate and chitosan co-modified liposomes can be developed as formulations for encapsulation and delivery of functional ingredients, providing a theoretical basis for developing new fucoxanthin series products.

Antioxidant and Anti-Aging Properties of Polyphenol-Polysaccharide Complex Extract from Hizikia fusiforme.

Hizikia fusiforme has a long history of consumption and medicinal use in China. It has been found that natural plants containing polyphenol-polysaccharide complexes have better activity compared with polyphenols and polysaccharides. Therefore, in this study on enzymatic hydrolysis and fractional alcohol precipitation, two kinds of polyphenol-polysaccharide complexes (PPC), PPC1 and PPC2, were initially obtained from Hizikia fusiforme, while the dephenolization of PPC1 and PPC2 produced PPC3 and PPC4. Through in vitro assays, PPC2 and PPC4 were found to have higher antioxidant activity, and thus were selected for testing the PPCs' anti-aging activity in a subsequent in vivo experiment with D-gal-induced aging in mice. The results indicated that PPCs could regulate the expressions of antioxidant enzymes and products of oxidation, elevate the expressions of genes and proteins related to the Nrf2 pathway in the mouse brain, enrich the gut microbiota species and increase the Bacteroidota-Firmicute (B/F) ratio. Above all, the Hizikia fusiforme polyphenol-polysaccharide complex has potential in the development of natural anti-aging drugs.

Anti-Hyperlipidemic Effect of Fucoidan Fractions Prepared from Iceland Brown Algae Ascophyllum nodosum in an Hyperlipidemic Mice Model.

Ascophyllum nodosum, a brown algae abundantly found along the North Atlantic coast, is recognized for its high polysaccharide content. In this study, we investigated the anti-hyperlipidemic effect of fucoidans derived from A. nodosum, aiming to provide information for their potential application in anti-hyperlipidemic therapies and to explore comprehensive utilization of this Iceland brown seaweed. The crude fucoidan prepared from A. nodosum was separated using a diethylethanolamine column, resulting in two fucoidan fractions, AFC-1 and AFC-2. Both fractions were predominantly composed of fucose and xylose. AFC-1 exhibited a higher sulfate content of 27.8% compared to AFC-2 with 17.0%. AFC-2 was primarily sulfated at the hydroxy group of C2, whereas AFC-1 was sulfated at both the hydroxy groups of C2 and C4. To evaluate the anti-hyperlipidemic effect, a hyperlipidemia mouse model was established by feeding mice a high-fat diet. The effects of AFC-1, AFC-2, and the crude extract were investigated, with the drug atorvastatin used as a positive comparison. Among the different fucoidan fractions and doses, the high dose of AFC-2 administration demonstrated the most significant anti-hyperlipidemic effect across various aspects, including physiological parameters, blood glucose levels, lipid profile, histological analysis, and the activities of oxidative stress-related enzymes and lipoprotein-metabolism-related enzymes (p < 0.05 for the final body weight and p < 0.01 for the rest indicators, compared with the model group), and its effect is comparable to the atorvastatin administration. Furthermore, fucoidan administration resulted in a lower degree of loss in gut flora diversity compared to atorvastatin administration. These findings highlight the significant biomedical potential of fucoidans derived from A. nodosum as a promising therapeutic solution for hypolipidemia.

Purification and Characterization of the Enzyme Fucoidanase from Cobetia amphilecti Utilizing Fucoidan from Undaria pinnatifida.

Fucoidanase is an unstable enzyme with high specificity that requires a large about of time to screen it from microorganisms. In this study, enzymatic hydrolysis was used to produce low-molecular-weight fucoidan from microorganisms via the degradation of high-molecular-weight fucoidan without damage to the sulfate esterification structure of oligosaccharide. The microbial strain HN-25 was isolated from sea mud and was made to undergo mutagenicity under ultraviolet light. Fucoidanase was extracted via ultrasonication and its enzymatic activity was improved via optimization of the ultrasonic conditions. The enzymatic properties and degradation efficiency of fucoidanase were characterized. The microbial strain HN-25 is a Gram-negative aerobic and rod-shaped-cell bacterium, and therefore was identified as Cobetia amphilecti via 16s rDNA. The results proved that fucoidanase is a hydrolytic enzyme with a molecular weight of 35 kDa and with high activity and stability at 30 °C and pH 8.0. The activity of fucoidanase was significantly enhanced by sodium and calcium ions and inhibited by a copper ion and ethylenediaminetetraacetate (EDTA). There was a significant decrease in the molecular weight of fucoidan after enzymatic hydrolysis. The low-molecular-weight fuicodan was divided into four fractions, mainly concentrated at F3 (20~10 kDa) and F4 (≤6 kDa). These consequences suggest that fucoidanase obtained from Cobetia amphilecti is stable and efficient and could be a good tool in the production of bioactive compounds.

Antioxidant Effects of Rhodoxanthin from Potamogeton crispus L. on H2 O2 -Induced RAW264.7 Macrophages Cells.

Potamogeton crispus L. (P. crispus) is the type of a widely distributed perennial herbs, which is rich in rhodoxanthin. In this research work, five antioxidant indexes in vitro were selected to study the antioxidant activity of rhodoxanthin from P. crispus (RPC). A model of hydrogen peroxide (H2 O2 ) -induced oxidative damage in RAW264.7 cells was established to analyze the antioxidant effect and potential mechanism of RPC. The levels of ROS, MDA and the activities of oxidation related enzymes by H2 O2 were determined by enzyme linked immunosorbent assay (ELISA). The mRNA expression of Nrf-2, HO-1, SOD1 and SOD2 was measured by qRT-PCR assay. According to the results, RPC had free radical scavenging ability for 2, 2-diphenyl-1-trinitrohydrazine (DPPH), 2,2'-azinobis(3-ethylbenzo-thiazoline-6-sulfonic acid radical ion) (ABTS), hydroxyl radical and superoxide anion. RPC significantly decreased the level of MDA and ROS and LDH activity, while increased GSH level and activities of SOD, GSH-Px and CAT. It was showed that RPC could increase the mRNA expression of Nrf-2, HO-1, SOD1 and SOD2 in RAW264.7 cells in a dose-dependently manner. In summary, RPC treatment could effectively attenuate the H2 O2 -induced cell damage rate, and the mechanism is related to the reduction of H2 O2 induced oxidative stress and the activation of Nrf-2 pathway.

Identification of Antioxidant Peptides Derived from Tilapia (Oreochromis niloticus) Skin and Their Mechanism of Action by Molecular Docking.

Antioxidants, which can activate the body's antioxidant defence system and reduce oxidative stress damage, are important for maintaining free radical homeostasis between oxidative damage and antioxidant defence. Six antioxidant peptides (P1-P6) were isolated and identified from the enzymatic hydrolysate of tilapia skin by ultrafiltration, reversed-phase high-performance liquid chromatography (RP-HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Moreover, the scavenging mechanism of the identified peptides against DPPH (2,2-Diphenyl-1-picrylhydrazyl) and ABTS (2-azido-bis (3-ethylbenzothiazoline-6-sulfonic acid) was studied by molecular docking. It was found that Pro, Ala and Tyr were the characteristic amino acids for scavenging free radicals, and hydrogen bonding and hydrophobic interactions were the main interactions between the free radicals and antioxidant peptides. Among them, the peptide KAPDPGPGPM exhibited the highest DPPH free radical scavenging activity (IC50 = 2.56 ± 0.15 mg/mL), in which the hydrogen bond between the free radical DDPH and Thr-6 was identified as the main interaction, and the hydrophobic interactions between the free radical DDPH and Ala, Gly and Pro were also identified. The peptide GGYDEY presented the highest scavenging activity against ABTS (IC50 = 9.14 ± 0.08 mg/mL). The key structures for the interaction of this peptide with the free radical ABTS were identified as Gly-1 and Glu-5 (hydrogen bond sites), and the amino acids Tyr and Asp provided hydrophobic interactions. Furthermore, it was determined that the screened peptides are suitable for applications as antioxidants in the food industry, exhibit good water solubility and stability, are likely nonallergenic and are nontoxic. In summary, the results of this study provide a theoretical structural basis for examining the mechanism of action of antioxidant peptides and the application of enzymatic hydrolysates from tilapia skin.

The efficient enrichment of marine peptides from the protein hydrolysate of the marine worm Urechis unicinctus by using mesoporous materials MCM-41, SBA-15 and CMK-3.

Peptides found in marine life have various specific activities due to their special growth environment, and there is increasing interest in the isolation and concentration of these biofunctional compounds. In this study, the protein hydrolysate of the marine worm Urechis unicinctus was prepared by enzymolysis and enriched by using mesoporous materials of silica MCM-41 and SBA-15 and carbon CMK-3. The differences in pore structures and elemental composition of these materials lead to differences in surface area and hydrophobicity. The adsorption capacities of peptides were 459.5 mg g-1, 431.3 mg g-1, and 626.3 mg g-1 for MCM-41, SBA-15 and CMK-3, respectively. Adsorption kinetics studies showed that the pseudo-second-order model fit the adsorption process better, where both external mass transfer and intraparticle diffusion affected the adsorption, while the Langmuir model better fit the adsorption of peptides on MCM-41 and SBA-15 and the Freundlich model was more suitable for CMK-3. Aqueous acetonitrile (ACN, 50/50, v/v) yielded the most extracted peptides. MALDI-TOF mass spectrometry of the extracted peptides showed that the three mesoporous materials, especially the CMK-3, gave good enrichment results. This study demonstrates the great potential of mesoporous materials in the enrichment of marine biofunctional peptides.

Overexpression and biochemical characterization of a truncated endo-α (1 → 3)-fucoidanase from alteromonas sp. SN-1009.

Endo-fucoidanases are important in structural analysis of fucoidans and preparation of fuco-oligosaccharides. However their enzymological properties and analysis of degradation products are scarcely investigated. Truncated endo-α (1 â†’ 3)-fucoidanase Fda1 (tFda1B from Alteromonas sp. was overexpressed and characterized, showing highest activity at pH 7.0, 35 °C, and 1.0 M NaCl. Its Km and kcat were 3.88 ± 0.81 mg/mL and 0.82 ± 0.17 min-1. Fe3+ and Mn2+ enhanced activity by 100% and 19.5% respectively. Co2+ and Cu2+ completely inactivated tFda1B, whereas Ni2+, Mg2+, Zn2+, Pb2+, Ca2+, Ba2+ and Li+ decreased activity by 58.8%, 56.0%, 50.6%, 47.7%, 28.9%, 15.6% and 37.5%, respectively. Catalytic residues were identified through structure and sequence alignment, and confirmed by mutagenesis. Degradation products of Kjellmaniella crassifolia fucoidan by tFda1B were characterized by LC-ESI-MS/MS, confirming tFda1B belongs to endo-(1 â†’ 3)-fucoidanases, and backbone of K. crassifolia fucoidan is 1 â†’ 3 fucoside linkage. This endo-α (1 â†’ 3)-fucoidanase would be useful for elucidating fucoidan structures, and be used as a food enzyme.

Gastric protective activities of fucoidan from brown alga Kjellmaniella crassifolia through the NF-κB signaling pathway.

Fucoidan has been reported to have abundant biological activities. The objective of the present study was to detect the protective effects of fucoidan from Kjellmaniella crassifolia (KF) newly cultured in Dalian, North of China on aspirin-induced gastric ulcers of the Wistar rat model. The present study showed that inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6 and IL-10 were effectively regulated in rats pretreated with KF. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities increased significantly in the KF pretreated groups, while the levels of maleic dialdehyde (MDA) decreased. The findings obtained by RT-PCR and western blotting indicated that KF could suppress aspirin-induced NF-κB activation via stabilization of IκB-α and thereby induced the downregulation of COX-2 and iNOS. It was demonstrated that KF exerted positive gastric protective effects via suppression of the inflammatory response and oxidative stress, and the mechanism of KF appeared to mediate the NF-κB signaling pathway.

Effects of a combined fucoidan and traditional Chinese medicine formula on hyperglycaemia and diabetic nephropathy in a type II diabetes mellitus rat model.

In this study, we innovatively propose a fucoidan mixed with traditional Chinese medicine formula (FCM) and evaluate its effects on hyperglycaemia and diabetic nephropathy in a type II diabetes mellitus Wistar rat model. After treatment with FCM for 8 weeks, the blood glucose, insulin resistance, serum lipid and antioxidant stress levels were significantly decreased (P < 0.05 or P < 0.01, vs. negative group). Via gene expression analysis, we found that three genes (InsR, GCK and GLUT-2) in the glucose metabolism pathway were significantly increased (P < 0.01, vs. negative group) in the FCM-treated groups and play important roles in hypoglycaemic activity. Moreover, FCM treatments alleviated (P < 0.01, vs. negative group) the urine protein, urine creatinine and pathological changes in the kidneys, producing significant improvements in renal function and structure. In summary, FCM exerts protective effects in diabetic rats and could be used in medicinal treatment for diabetes mellitus and its complications.

Hypolipidemic effects of fucoidan fractions from Saccharina sculpera (Laminariales, Phaeophyceae).

Fucoidan is a kind of brown algae-derived macromolecule suggested to have hypolipidemic activity. Saccharina sculpera has attracted interest because it is rich in fucoidan. The monosaccharide composition and structural characteristics of isolated fractions (F1, F2 and F3) were determined using high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). The hypolipidemic effects of fucoidan fractions from Saccharina sculpera cultured in northern China were clarified by measuring cholesterol levels, antioxidative indicators and hepatic gene mRNA expression using an established hyperlipidemic Wistar rat model. The results showed that F1 is an acetylated galactofucan and that F2 consists of fucose, galactose, mannose and glucuronic acid. F3 is an acetylated galactofucan with high fucose. Fucoidan fractions from Saccharina sculpera could effectively reduce the level of lipids in serum by reducing the TG, TC, and LDL-C levels and increasing HDL-C levels and could effectively prevent lipid accumulation in the liver. The findings obtained from hepatic gene expression showed that fucoidan could inhibit cholesterol synthesis via downregulation of HMG-CoA-R and upregulation of LCAT, slow the synthesis of fatty acids via downregulation of SREBP-1c, and promote ß-oxidation of fatty acids via upregulation of PPARα, PPARγ and LPL. These results demonstrated that the hypolipidemic activity of fucoidan was related to the inhibition of cholesterol synthesis and reverse transport, the regulation of fatty acid synthesis, and acceleration of mitochondrial ß-oxidation.

In vitro and in vivo immunomodulatory effects of fucoidan compound agents.

Fucoidan extracted from brown algae displays diverse biological activities. In the present study, fucoidan was mixed with Chinese herb extracts, and the in vitro and in vivo immunomodulatory effects of two fucoidan compound agents were evaluated. The results showed that fucoidan from Kjellmaniella crassifolia (KF) and Undaria pinnatifida (UF) were sulfated polysaccharides, Astragalus polysaccharide (AP) was composed of α-d-glucose, and Codonopsis pilosula polysaccharide (CPP) was a furanose. Furthermore, fucoidan compound agents stimulated mouse macrophage RAW264.7 cell proliferation and enhanced the secretion of granulocyte-macrophage colony stimulating factor (GM-CSF) and tumour necrosis factor-α (TNF-α) in vitro. In addition, KCA (KF + AP + CPP) and UCA (UF + AP + CPP) could improve the nonspecific immunity and the specific immunity of BALB/c mice. Fucoidan compound agents also increased the secretion of GM-CSF, TNF-α, interleukin (IL)-4 and IL-10 in vivo. Therefore, we confirmed that fucoidan compound agents have promise for development as supplementary immunopotentiators.

Structural characterization and antitumor effects of fucoidans from brown algae Kjellmaniella crassifolia farmed in northern China.

Brown alga-derived fucoidan has been proven to have a variety of bioactivities. To explore the antitumor effect of fucoidan, Kjellmaniella crassifolia (farmed in Dalian, China)was enzymatically digested to obtain the crude extract (F), which was further separated into three fractions (F1, F2 and F3). The monosaccharide composition and structural characteristics of the isolated fractions were determined using high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR) and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. F1 is an acetylated galactofucan, and F2 consists of fucose, galactose, mannose and glucuronic acid. F3 has two components, an acetylated galactofucan and a pure sulfated fucan. F, F1 and F2 showed limited cytotoxicity against murine hepatocarcinoma Hca-F cells in vitro. Oral administration of F at a dose of 450 mg/kg d significantly inhibited lump growth in Hca-F-inoculated mice and led to upregulated FAS expression in tumor tissues compared to that of the control. F1 and F2 did not show competitive antineoplastic efficacy, as did the crude extract. Crude fucoidan could be a promising antitumor adjuvant. The origin of its efficacy may be the small molecules, such as phenols that attached to native fucoidan. This theory needs to be further confirmed.

Studies on the hepatoprotective effect of fucoidans from brown algae Kjellmaniella crassifolia.

For illustrating the relation of different structural characteristics correlated with the hepatoprotective effect, studies of fucoidan from algae Kjellmaniella crassifolia, a brown alga distributed in north Japan, were carried out. The fucoidan fractions of K. crassifolia were extracted, separated, and purified using a combinatorial procedure consisting of enzymolysis, ethanol precipitation, DEAE and size-exclusion chromatographies. The fundamental characteristics of the four enriched fucoidan fractions (KF1-KF4), including their sulphate content and monosaccharide composition, were investigated. The fucose was the main composition of monosaccharide for KF1-KF4, that of KF4 was up to 91.4%. The Glu-UA was the special composition of monosaccharide. FTIR and NMR spectroscopy were employed to elucidate the structural features of all fractions which further illustrated that fucose was the main monosaccharide. It was found all the four fractions showed antioxidative activity against hydroxyl radical and had the bioactive effects on CCl4-induced liver injury.

Structural characterisation of algae Costaria costata fucoidan and its effects on CCl4-induced liver injury.

Fucoidan is a well-known natural product that is commonly found in brown algae and shows a variety of activities, including immunomodulation, antioxidation, and the combat of carcinogens. The fucoidan fractions of Costaria costata, a brown algae introduced from Japan and cultured in northern China, were studied. The fucoidan fractions were extracted, separated, and purified using a combinatorial procedure consisting of enzymolysis, ethanol precipitation, and DEAE and size-exclusion chromatographies. The fundamental characteristics of the four enriched fucoidan fractions (F1-F4), such as their sulphate content and monosaccharide composition, were investigated. FTIR and NMR spectroscopy were employed to further elucidate the structural features of the four fractions. It was found that the F1-F4 fractions all showed oxidative activity against hydroxyl radicals. The bioactive effects of the fucoidan fractions on CCl4-induced liver injury suggest their potential use as ingredients for functional foods or pharmaceuticals.

Novel antioxidative peptides from the protein hydrolysate of oysters (Crassostrea talienwhanensis).

The antioxidative activity of hydrolysate peptides from oysters (Crassostrea talienwhanensis) was investigated. After hydrolysis with subtilisin, the yields of the peptides that were soluble in trichloroacetic acid (TCA-soluble) and the antioxidant activities of the resulting hydrolysate were determined using an orthogonal design and a hydroxyl radical scavenging reaction. The hydrolysate was fractionated using Sephadex G-15 gel filtration chromatography, and the two resulting bioactive peptides were subsequently purified by RP-HPLC with a Kromasil C18 (ODS) column. The amino acid sequences were analyzed by nano-ESI-MS/MS. The critical reaction temperature, pH, hydrolysis time and enzyme-to-substrate (E/S) ratio were determined for the optimum hydrolysis with subtilisin, and the E/S ratio was found to be the most critical reaction condition. The amino acid sequences of the peptides (518 and 440 Da) were proline-valine-methionine-glycine-aspartic acid (PVMGA) and glutamine-histidine-glycine-valine (QHGV), respectively. These two novel peptides exhibited high antioxidative actions based on their hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities.