Preparation of low molecular weight Sargassum fusiforme polysaccharide and its anticoagulant activity

Heparin has been used as an anticoagulant drug for many years, but it has significant side ef fects. In the search for good substitutes, low molecular weight(MW) polysaccharides from S argassum fusiforme have been examined and confi rmed to possess biological activities. Here, S. fusiforme polysaccharides(SFP) were extracted and subjected to a hydrogen peroxide(H_2O_2) oxidation method for the preparation of low-MW SFP(LSFP). The effects of temperature, pH, and H_2O_2 concentration on the degradation process were also examined. Several LSFP of 36, 9, 5.7, and 2.7 kDa were obtained under different conditions, and their anticoagulant activities studied in vitro. The results showed that SFP and LSFP prolonged activated partial thromboplastin(APTT), prothrombin(PT) and thrombin times(TT) significantly, indicating that these low MW polysaccharides possessed anticoagulant activity in the intrinsic, extrinsic, and common coagulation pathways. As these ef fects were related to the MW of the polysaccharides in APTT and TT but not in PT, the contents of the monosaccharide fucose and sulfate and the polysaccharide MW could have exerted combined ef fects. The details of this mechanism require further verifi cation.     

Study on the Free Radical Scavenging Activity of Sea Cucumber (Paracaudina chinens var.) Gelatin Hydrolysate

Gelatin from the sea cucumber(Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff(MWCO). The portion(less than 5 kDa) was further separated by Sephadex G-25. The active peak was col-lected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals(O2·-) and hydroxyl radi-cals(·OH) of the fraction with the highest activity were 29.02% and 75.41%,respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.     

Study on the Free Radical Scavenging Activity of Sea Cucumber （Paracaudina chinens vat.） Gelatin Hydrolysate

Gelatin from the sea cucumber （Paracaudina chinens var.） was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff （MWCO）. The portion （less than 5 kDa） was further separated by Sephadex G-25. The active peak was collected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals （O2·^-） and hydroxyl radicals （·OH） of the fraction with the highest activity were 29.02% and 75.41%, respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.     

In-vitro anticoagulant activity of fucoidan derivatives from brown seaweed Laminaria japonica

Fucoidan, a group of sulfated heteropolysaccharides, was extracted from Laminaria japonica, an important economic alga species in China. The anticoagulant activity of fucoidan and its derivatives (including sulfated, phosphorylated, and aminated fucoidan) was examined using in-vitro anticoagulant systems. The correlation between chemical variations within the fucoidan group and anticoagulant activity was determined. The in-vitro anticoagulant properties of fucoidan and its derivatives were determined by measuring activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). The results indicate anticoagulant activity in all samples using APTT and TT assays; however, only the fucoidan derivatives affected the PT assay. Thus, the fucoidan derivatives were able to inhibit both intrinsic and extrinsic blood coagulants. Fucoidan (FPS) and its derivatives presented better anticoagulant activity than low molecular weight fucoidan (DFPS) and its derivatives, suggesting that molecular weight and proper conformation are contributing factors for anticoagulant activity of polysaccharides. Amino groups have a positive charge and can thus change the charge density of fucoidan. Accordingly, among the tested samples, aminated fucoidan (NF) was the most active reflecting the importance of charge density for anticoagulant activity. Available data obtained using in-vitro models suggest that the sulfate content, sulfate/total-sugar ratio, molecular weight, and the substituted group of fucoidan are important factors for anticoagulant activity but that the influence of sulfate, phosphate and amino groups on anticoagulant activity was different.     

Polysaccharides in <Emphasis Type="Italic">Sipunculus nudus</Emphasis>: Extraction condition optimization and antioxidant activities

Marine organisms constitute unlimited resource of bioactive substances due to their high biodiversity and represent a valuable source of new compounds. This study optimized the alkali-extraction conditions and antioxidant activities of soluble polysaccharides from the body wall of Sipunculus nudus. The effects of solid-liquid ratio, extraction duration, extraction temperature, and alkali concentration on the yield of S. nudus polysaccharides (SNP) were examined, according to which the optimal combination of extraction parameters was obtained by an orthogonal test. The relative influencing importance of different extraction parameters on the yield of SNP followed the order as solid-liquid ratio > extraction temperature > alkali concentration > extraction duration. The highest extraction yield, 1.98%, was achieved under an optimal extraction condition: temperature 60°C, solid-liquid ratio 1:6 g mL^?1, duration 5 h, and alkali (NaOH) mass fraction 6%. The in vitro antioxidant activities examination showed that extracted SNP under this optimized condition had strong power in reducing certain hydroxyl and superoxide radical scavenging abilities. The promising results showed that extracted SNP could be a potent natural antioxidant.     

不同方式提取的近江牡蛎糖蛋白的体外抗氧化活性

比较研究了水浸提、盐液浸提及超声辅助盐液浸提的近江牡蛎糖蛋白粗提物对羟自由基、DPPH自由基、超氧阴离子自由基的清除效果。结果表明:水浸提、盐液浸提及超声辅助盐液浸提的糖蛋白中可溶性蛋白与总糖含量之比分别为1.83∶1、4.49∶1和2.51∶1;3种糖蛋白粗提物均具有一定的清除羟自由基、DPPH自由基和超氧阴离子自由基的能力;它们对羟自由基的清除能力高于对DPPH自由基和超氧阴离子自由基;盐液浸提物清除超氧阴离子的能力最弱;超声辅助盐液浸提的糖蛋白粗提物清除羟自由基、超氧阴离子自由基及DPPH自由基的能力比水浸提和盐液浸提的糖蛋白的能力强。     

Comparative Study on the Antioxidant Activity of Peptides from Pearl Oyster(Pinctada martensii) Mantle Type V Collagen and Tilapia(Oreochromis niloticus) Scale Type Ⅰ Collagen

In this study, Pearl oyster mantle type V collagen(POMC) and tilapia scale type I collagen(TSC) were extracted and hydrolyzed by various proteases in order to obtain peptides. The antioxidant activity of the peptides was investigated by DPPH, hydroxyl radical scavenging experiments and a dynamic digestion model in vitro. The results show that there are significant differences in amino acid composition between POMC and TSC. The collagen peptides obtained from pearl oyster mantle(POMCP) by treating with alkaline protease exhibited higher antioxidant activity than that from tilapia scale(TSCP) treated with papaya protease, and both of them showed greater DPPH and hydroxyl radical scavenging activity than other peptides. After being separated via Sephadex G-25 chromatography, the M1 fraction isolated from POMCP, and the S1 fraction from TSCP with which both had higher molecular weights showed the strongest antioxidant activity than other fractions, and the M1 fraction exhibited stronger antioxidant activity than the S1 fraction in scavenging free-radicals and protecting cells from the oxidation damage. Furthermore, after treating the dynamic digestion system model in vitro, the DPPH and hydroxyl radical scavenging activity of the M1 fraction increased slightly. These results suggest that POMCP exhibits stronger antioxidant activity than TSCP, which means that PMOP may be a good candidate to be a potential natural antioxidant in the food-processing industry.     

Chemical characteristics and anticoagulant activities of two sulfated polysaccharides from Enteromorpha linza (Chlorophyta)

Two sulfated polysaccharides, designated MP and SP, were extracted from the marine green alga Enteromorpha linza using hot water and then purified using ion-exchange and size-exclusion chromatography. The anticoagulant activities of MP and SP were examined by determination of their activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) using human plasma. Results showed that MP and SP were composed of abundant rhamnose with small amounts of xylose and glucuronic acid, whereas SP also contained a small amount of galactose. Approximate molecular weights of MP and SP were 535 and 502 kDa, respectively. As compared with SP, MP had higher contents of sulfate ester (19.0%) and uronic acid (14.9%). The MP mainly consisted of (1→4)-linked rhamnose residues with partially sulfated groups at the C-3 position, and small amounts of (1→3, 4)-linked rhamnose, (1→2, 4)-linked rhamnose, (1→4)-linked glucuronic acid and (1→4)-linked xylose residues. The SP contained abundant (1→4)-linked rhamnose with minor amounts of (1→3)-linked rhamnose, (1→3, 4)-linked rhamnose, (1→2, 4)-linked rhamnose, (1→4)-linked glucuronic acid, (1→4)-linked xylose, and (1→3)-linked galactose residues. The sulfate groups were mainly located at C-3 of (1→4)-linked rhamnose residues. Both MP and SP, in particular the former, effectively prolonged APTT and TT. This work demonstrates that MP and SP have unique structural characteristics distinct from those of other sulfated polysaccharides from Enteromorpha. The MP is a potential source of anticoagulant, and the difference in anticoagulant activities of the two sulfated polysaccharides is directly linked to the discrepancy of their chemical features.     

The preparation and antioxidant activity of glucosamine sulfate

Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O-2)/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfa...     

The antioxidant effects of complexes of tilapia fish skin collagen and different marine oligosaccharides

An excess of reactive oxygen species (ROS) leads to a variety of chronic health problems.As potent antioxidants, marine bioactive extracts containing oligosaccharides and peptides have been extensively studied.Recently, there is a growing interest in protein-polysaccharide complexes because of their potential uses in pharmaceutical and food industries.However, only few studies are available on the antioxidant activities of such complexes, in terms of their ROS scavenging capability.In this study, we combined different marine oligosaccharides (isolated and purified) with collagen peptides derived from tilapia fish skin, and evaluated the an-tioxidant activity of the marine peptide-oligosaccharide complexes vis-à-vis the activity of their original component molecules.Bio-chemical and cellular assays were performed to measure the scavenging effects on 1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide radicals, and to evaluate the influences on the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the level of malondialdehyde (MDA) in UV-induced photoaging models.The results indicated that the antioxidant activities of all the complexes were stronger than those of their individual components.Among the 11 complexes tested, two complexes, namely MA1000+CP and κ-ca3000+CP, turned out to be highly effective antioxidants.Although the detailed mechanisms of this improved scavenging ability are not fully understood, this work provides insights into the design of highly efficient peptide-oligosaccharide complexes for potential applications in pharmaceutical, cosmetics and food industries.     

Bioactive compounds of sea cucumbers and their therapeutic effects

Sea cucumbers belong to the Class Holothuroidea of marine invertebrates. They are commercially valuable and prized as a food and folk medicine in Asia. Nutritionally, sea cucumbers have an impressive profile of valuable nutrients such as vitamins, minerals and amino acids. A number of unique biological and pharmacological activities/properties, including anticancer, anticoagulant/antithrombotic, antimicrobial, antioxidant, antihyperlipidemic, antihyperglycemic, anti-inflammatory, antihypertension and radioprotective, have been ascribed to various compounds isolated from sea cucumbers. The therapeutic properties and medicinal benefits of sea cucumbers can be linked to the presence of a wide array of bioactives, especially triterpene glycosides, acid mucopolysaccharide, sphingoid bases, glycolipids, fucosylated chondroitin sulfate, polysaccharides, phospholipids, cerebrosides, phosphatidylcholines, and other extracts and hydrolysates. This review highlights the valuable bioactive components as well as the multiple therapeutic properties of sea cucumbers with a view to exploring their potential uses as functional foods and a natural source of new multifunctional drugs.     

The scavenging of free radical and oxygen species activities and hydration capacity of collagen hydrolysates from walleye pollock (Theragra chalcogramma) skin

Fish skin collagen hydrolysates (FSCH) were prepared from walleye pollock (Theragra chalcogramma) using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical (DPPH), superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione (GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore, FSCH may have potential applications in the medicine and food industries.     

Isolation and characterization of fucoidans from five brown algae and evaluation of their antioxidant activity

In this study, we evaluated the chemical property and antioxidant activity of fucoidans isolated from brown algae, Laminaria japonica(LJF), Lessonia nigrescens(LNF), Lessonia trabeculata(LTF), Ascophyllum mackaii(AMF), and Ecklonia maxima(EMF). LJF was less in sulfate content(14.16%) and more in galactose and mannose content(1.08 and 0.68) than the documented early. EMF contained 20%–30% of sulfate and fucose, 0.97 in molar ratio which was lower than that of sulfate to other four fucoidans(1.21–1.41). AMF(162 kDa) and EMF(150 kDa) were the first two largest in molecular weight, which were followed by LJP(126 kDa), LNF(113 kDa) and LTF(105 kDa). The fucoidans isolated these algae showed a wide range of antioxidant activity in vitro. It was found that the reducing power of the isolated fucoidans was positively correlated with their sulfate content and molecular weight. In addition, LNF and LTF at low concentrations exhibited high superoxide and hydroxyl radical scavenging activity. This demonstrated that low molecular weight fucoidans may perform a high antioxidant activity.     

Study on extraction of agaropectin from Gelidium amansii and its anticoagulant activity

Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially. The yields of 1.0 mol/L NaCl fraction and 2.5 mol/L NaCl fraction were 2.80% and 2.03%. They are highly sulfated agar, and named as agaropectin with sulfate content being 22.8% and 32.5%, respectively. The anticoagulant experiment results show that agaropectin could effectively prolong the coagulation time in a dose-dependent manner in vitro. Agaropection could be absorbed and effectively prolong the plasma coagulation time in vivo. After intragastric administration at the doses of 100, 200, and 400 mg/kg-d in rats for 15 days, TT （thrombin time）, CT （coagulation time）, PT （prothrombin time）, and APTT （activated partial thromboplastin time） could be effectively prolonged and the plasma Fib level could be significantly lowered.     

Mechanical Stress Induces Neuroendocrine and Immune Responses of Sea Cucumber(Apostichopus japonicus)

Grading procedure in routine sea cucumber hatchery production is thought to affect juvenile sea cucumber immunological response. The present study investigated the impact of a 3-min mechanical perturbation mimicking the grading procedure on neuroendocrine and immune parameters of the sea cucumber Apostichopus japonicus. During the application of stress, concentrations of noradrenaline and dopamine in coelomic fluid increased significantly, indicating that the mechanical perturbation resulted in a transient state of stress in sea cucumbers. Coelomocytes concentration in coelomic fluid increased transiently after the beginning of stressing, and reached the maximum in 1 h. Whereas, coelomocytes phagocytosis at 3 min, superoxide anion production from 3 min to 0.5 h, acid phosphatase activity at 0.5 h, and phenoloxidase activity from 3 min to 0.5 h were all significantly down-regulated. All of the immune parameters recovered to baseline levels after the experiment was conducted for 8 h, and an immunostimulation occurred after the stress considering the phagocytosis and acid phosphatase activity. The results suggested that, as in other marine invertebrates, neuroendocrine/immune connections exist in sea cucumber A. japonicus. Mechanical stress can elicit a profound influence on sea cucumber neuroendocrine system. Neuroendocrine messengers act in turn to modulate the immunity functions. Therefore, these effects should be considered for developing better husbandry procedures.     

Polyguluronate Sulfate,Polymannuronate Sulfate,and Their Oligosaccharides Have Antithrombin Ⅲ-and Heparin Cofactor Ⅱ-independent Anticoagulant Activity

Cardiovascular disease is the leading causes of death.However,the complications can be treated with heparin and heparinoids,such as heparin pentasaccharide Fondaparinux,dermatan sulfate,and PSS made from alginate extracted from brown seaweeds by chemical sulfation.Alginate is composed of a linear backbone of polymannuronate(PM),polyguluronate(PG),and alternate residues of mannuronic acid and guluronic acid.It is unknown if heparin and sulfated PG(PGS)/PM(PMS) have the same or different anticoagulant molecular targets.In the current study,the anticoagulant activities of PGS,PMS,and their oligosaccharides were directly compared to that of heparin,Fondaparinux,and dermatan sulfate by the activated partial thrombinplastin time(aP TT) assay using normal,antithrombin III(ATIII)-deficient,heparin co-factor II(HCII)-deficient,and ATIII-and HCII-double deficient human plasmas.Our results showed that PGS,PMS,and their oligosaccharides had better anticoagulant activity than that of Fondaparinux in all four human plasmas tested.As expected,heparin was the best anticoagulant in normal plasma.Moreover,PGS,PGS6,PGS12,PGS25,PMS6,PMS12,and PMS25 were better anticoagulants than dermatan sulfate in HCII-deficient plasma.Most strikingly,PGS,PGS12,PGS25,PMS6,PMS12,and PMS25 were better anticoagulants than that of heparin in ATIII-and HCII-double deficient human plasma.The results revealed for the first time that sulfated alginate had ATIII-and HCII-independent anticoagulant activities.Therefore,developing PGS and PMS-based anticoagulants might require to discover their major molecular targets and to develop target-specific anticoagulant assays.     

Chemical constituents and antioxidant activities of waste liquid extract from Apostichopus japonicus Selenka processing

Apos tichopus japonicus Selenka is an ideal tonic food that is used traditionally in many Asian countries, and it contains many bioactive substances, such as antioxidant, antimicrobial, and anticancer materials. To convert waste liquid generated during production into a useful resource, extract from waste liquid was isolated by column chromatography and studied by the pyrogallol autoxidation and 1,10-phenanthroline-Fe²⁺ oxidation methods. Results show that the extract scavenged about 91% of the superoxide anion radical at a concentration of 1.4 mg/mL and 24% of the hydroxyl radical at 3.3 mg/mL. Four compounds were isolated and identified from the extract: 2,4-dihydroxy-5-methyl-1,3-azine; 2,4-dihydroxy-1,3-diazine; 3-O-[β-D-quinovopranosyl-(1→2)-4-O-sodium sulfate-β-D-xylopranosyl]-holosta-9(11)-ene-3β,12α,17α-triol; and 24-ethyl-5α-cholesta-7-ene-3β-O-β-D-xylopyranoside. All of these compounds are known in A. japonicus, and were found in the waste liquid for the first time.     

Antioxidation activities of low-molecular-weight gelatin hydrolysate isolated from the sea cucumber <Emphasis Type="Italic">Stichopus japonicus</Emphasis>

Gelatin extracted from the body wall of the sea cucumber (Stichopus japonicus) was hydrolyzed with flavourzyme. Low-molecular-weight gelatin hydrolysate (LMW-GH) of 700–1700 Da was produced using an ultrafiltration membrane bioreactor system. Chemiluminescence analysis revealed that LMW-GH scavenges high free radicals in a concentration-dependent manner; IC₅₀ value for superoxide and hydroxyl radicals was 442 and 285 μg mL⁻¹, respectively. LMW-GH exhibited excellent inhibitory characteristics against melanin synthesis and tyrosinase activity in B16 cells. Furthermore, LMW-GH notably increased intracellular glutathione (GSH), which in turn suppressed melanogenesis. LMW-GH performs antioxidation activity, holding the potential of being used as a valuable ingredient in function foods, cosmetics and pharmaceuticals or nutriceuticals.     

Free radical scavenging abilities of polypeptide from Chlamys farreri

1 INTRODUCTION Active oxygen free radicals can damage cell structure, even kill the cells, causing aging and cer- tain serious diseases (Bors et al., 1989). Usually, the production and scavenging of active oxygen free radicals are in balance in healthy hu…     

The Scavenging of Free Radical and Oxygen Species Activities and Hydration Capacity of Collagen Hydrolysates from Walleye Pollock(Theragra chalcogramma) Skin

Fish skin collagen hydrolysates (FSCH) were prepared from walleye pollock (Theragra chalcogramma) using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical (DPPH), superox-ide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione (GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scav-enge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore, FSCH may have potential applications in the medicine and food industries.