ABSTRACT
Developing a photocatalyst that can effectively utilize the full solar spectrum remains a high-priority objective in the ongoing pursuit of efficient light-to-chemical energy conversion. Herein, the ternary nanocomposite g-C3N4/RGO/W18O49 (CN/RGO/WO) was constructed and characterized by a variety of techniques. Remarkably, under the excitation of photon energies ranging from the ultraviolet (UV) to the near-infrared (NIR) region, the photocatalytic performance of the CN/RGO/WO nanocomposite exhibited a significant enhancement compared with single component g-C3N4 or W18O49 nanosheets for the degradation of methyl orange (MO). The MO photodegradation rate of the optimal CN/1.0 wt% RGO/45.0 wt% WO catalyst reached 0.816 and 0.027 min-1 under UV and visible light excitation, respectively. Even under low-energy NIR light, which is not sufficient to excite g-C3N4, the MO degradation rate can still reach 0.0367 h-1, exhibiting a significant enhancement than pure W18O49. The outstanding MO removal rate and stability were demonstrated by CN/RGO/WO nanocomposites, which arise from the synergistic effect of localized surface plasmon resonance effect induced by W18O49 under vis-NIR excitation and the Z-scheme nanoheterojunction of W18O49 and g-C3N4. In this work, we have exploited the great potential of integrating nonmetallic plasmonic nanomaterials and good conductor RGO to construct high-performance g-C3N4-based full-solar spectral broadband photocatalysts.
ABSTRACT
The polysaccharide from green alga Cladophora oligoclada, OHSS2, was a sulfated galactoarabinan which was constituted by a backbone of (1 â 4)-ß-l-arabinopyranose units with partial sulfate at C-3 of (1 â 4)-ß-l-arabinopyranose units. The side chains containing (1 â 4)-ß-l-arabinopyranose, (1 â 4)-ß-d-galactopyranose and/or (1 â 4,6)-ß-d-galactopyranose units were in C-2/C-3 of (1 â 4)-ß-l-arabinopyranose units. OHSS2 had strong anti-diabetic activity in vitro assessed by inhibition of human islet amyloid polypeptide (hIAPP) aggregation. The mechanism analysis of anti-diabetic activity showed that OHSS2 diminished the production of intracellular reactive oxygen species and alleviated hIAPP aggregation-induced oxidative stress in NIT-1 cells. OHSS2 stabilized mitochondrial membrane potential, and enhanced the mitochondrial complex I, II or III activity and ATP level. Thus, OHSS2 effectively protected mitochondria from hIAPP aggregation-induced damage. Furthermore, OHSS2 was co-localized with mitochondria and could have a direct influence on mitochondrial function. These results revealed that OHSS2 had potential as a novel anti-diabetic agent.
Subject(s)
Chlorophyta/chemistry , Galactans/pharmacology , Hypoglycemic Agents/pharmacology , Islet Amyloid Polypeptide/antagonists & inhibitors , Sulfates/pharmacology , Animals , Cells, Cultured , Galactans/chemistry , Galactans/isolation & purification , Hypoglycemic Agents/chemistry , Hypoglycemic Agents/isolation & purification , Islet Amyloid Polypeptide/metabolism , Mice , Oxidative Stress/drug effects , Protein Aggregates/drug effects , Reactive Oxygen Species/metabolism , Sulfates/chemistry , Sulfates/isolation & purificationABSTRACT
Marine macroalgae are efficient producers of sulfated polysaccharides. The algal sulfated polysaccharides possess diverse bioactivities and peculiar chemical structures, and represent a great potential source to be explored. In the present study, a heparinoid-active sulfated polysaccharide was isolated from the green alga Cladophora oligoclada. Results of chemical and spectroscopic analyses indicated that the sulfated polysaccharide was composed of â6)-ß-d-Galp-(1â, ß-d-Galp-(1â, â6)-α-d-Glcp-(1â and â3)-ß-d-Galp-(1â units with sulfate esters at C-2/C-4 of â6)-ß-d-Galp-(1â, C-6 of â3)-ß-d-Galp-(1â and C-3 of â6)-α-d-Glcp-(1â units. The branches consisting of ß-d-Galp-(1â and â6)-ß-d-Galp-(1â units were located in C-3 of â6)-ß-d-Galp-(1â units. The sulfated polysaccharide exhibited potent anticoagulant activity in vitro and in vivo as evaluated by activated partial thromboplastin time (APTT), thrombin time, and the fibrinogen level. For the APTT, the signal for clotting time was more than 200 s at 100 µg/mL in vitro and at 15 mg/kg in vivo. The obvious thrombolytic activity of the sulfated polysaccharide in vitro was also found. The mechanism analysis of anticoagulant action demonstrated that the sulfated polysaccharide significantly inhibited the activities of all intrinsic coagulation factors, which were less than 1.0% at 50 µg/mL, but selectively inhibited common coagulation factors. Furthermore, the sulfated polysaccharide strongly stimulated the inhibition of thrombin by potentiating antithrombin-III (AT-III) or heparin cofactor-II, and it also largely promoted the inhibition of factor Xa mediated by AT-III. These results revealed that the sulfated polysaccharide from C. oligoclada had potential to become an anticoagulant agent for prevention and therapy of thrombotic diseases.
Subject(s)
Anticoagulants/pharmacology , Chlorophyta , Polysaccharides/pharmacology , Animals , Anticoagulants/chemistry , Aquatic Organisms , Blood Coagulation/drug effects , Male , Models, Animal , Partial Thromboplastin Time , Polysaccharides/chemistry , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Sulfates , Thrombin TimeABSTRACT
A sulfated polysaccharide from the green alga Chaetomorpha linum, designated CLS4, was isolated by water extraction, anion-exchange and size-exclusion chromatography. Chemical and spectroscopic analyses demonstrated that CLS4 was a sulfated arabinogalactan, which was constituted by (1â6)-ß-d-galactopyranose and (1â5)-α-l-arabinofuranose residues with sulfate groups at C-2/ C-3 of (1â5)-α-l-arabinofuranose and C-2/C-4 of (1â6)-ß-d-galactopyranose. CLS4 possessed strong anticoagulant activity in vitro or in vivo as evaluated by activated partial thromboplastin time and thrombin time assays. CLS4 largely inhibited the activities of the coagulation factors XII, XI, IX and VIII. CLS4 was a potent thrombin inhibitor mediated by antithrombin III (ATIII) or heparin cofactor II, and it also effectively stimulated the factor Xa inhibition by potentiating ATIII. Moreover, CLS4 had a high thrombolytic activity in vitro as assessed by clot lytic rate assay. The results suggested that CLS4 could be a promising source of anticoagulant agent.
Subject(s)
Anticoagulants/pharmacology , Blood Coagulation Factors/antagonists & inhibitors , Chlorophyta/chemistry , Galactans/pharmacology , Sulfates/pharmacology , Anticoagulants/chemistry , Anticoagulants/isolation & purification , Carbohydrate Conformation , Galactans/chemistry , Galactans/isolation & purification , Humans , Sulfates/chemistry , Sulfates/isolation & purificationABSTRACT
A water-soluble polysaccharide from Monostroma nitidum, designated MWS, was isolated using water extraction, anion-exchange and size-exclusion chromatography. MWS was a sulfated glucuronorhamnan consisting of â3)-α-l-Rhap-(1â, â4)-ß-d-GlcpA-(1â and â2)-α-l-Rhap-(1â units. Sulfate ester groups located at C-4/C-2 of â3)-α-l-Rhap-(1â and C-4/C-3 of â2)-α-l-Rhap-(1â units. In in vitro tests, it was proved that MWS possessed broad spectrum against different viruses, especially for enterovirus 71 (EV71) with nearly no toxicity in relation to cell lines used. MWS may largely inhibit EV71 infection before or during viral adsorption through binding to virus particles and block some early steps of virus life cycle by down-regulating host phosphoinositide 3-kinase /protein kinase B signaling pathway. Intramuscular injection of MWS markedly reduced viral titers in EV71-infected mice. The data demonstrated that MWS could have great promising to become an antiviral drug for prevention and therapy of EV71 infection.
Subject(s)
Antiviral Agents/therapeutic use , Chlorophyta , Enterovirus A, Human/drug effects , Enterovirus Infections/drug therapy , Mannans/therapeutic use , Sulfates/therapeutic use , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Chlorocebus aethiops , Dogs , Enterovirus Infections/virology , Female , Madin Darby Canine Kidney Cells , Mannans/chemistry , Mannans/pharmacology , Mice, Inbred ICR , Molecular Structure , Seaweed , Sulfates/chemistry , Sulfates/pharmacology , Vero CellsABSTRACT
Sulfated polysaccharides from marine algae have high potential as promising candidates for marine drug development. In this study, a homogeneous sulfated polysaccharide from the marine green alga Monostroma nitidum, designated MS-1, was isolated using water extraction and anion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that MS-1 mainly consisted of â3)-α-l-Rhap-(1â and â2)-α-l-Rhap-(1â residues, with additional branches consisting of 4-linked ß-d-xylose, 4-/6-linked d-glucose, terminal ß-d-glucuronic acid, and 3-/2-linked α-l-rhamnose. Sulfate ester groups substituted mainly at C-2/C-4 of â3)-α-l-Rhap-(1â and C-4 of â2)-α-l-Rhap-(1â residues, slightly at C-2 of terminal ß-d-glucuronic residues. MS-1 exhibited strong anticoagulant activity in vitro and in vivo as evaluated by the activated partial thromboplastin time and thrombin time assays, and significantly decreased platelet aggregation. The anticoagulant activity mechanism of MS-1 was mainly attributed to strong potentiation thrombin by heparin cofactor-II, and it also hastened thrombin and coagulation factor Xa inhibitions by potentiating antithrombin-III. MS-1 possessed markedly thrombolytic activity evaluated by plasminogen activator inhibitior-1, fibrin degradation products, and D-dimer levels using rats plasma, and recanalization rate by FeCl3-induced carotid artery thrombosis in mice. MS-1 exhibited strong antithrombotic activity in vitro and in vivo evaluated by the wet weighs and lengths of thrombus, and thrombus occlusion time by electrically-induced carotid artery thrombosis in rats. These results suggested that MS-1 could be a promising marine drug for prevention and therapy of thromboembolic disease.
Subject(s)
Anticoagulants/pharmacology , Blood Coagulation/drug effects , Chlorophyta/chemistry , Fibrinolytic Agents/pharmacology , Polysaccharides/pharmacology , Sulfates/pharmacology , Animals , Carotid Artery Thrombosis/blood , Carotid Artery Thrombosis/chemically induced , Humans , Male , Mice , Platelet Aggregation/drug effects , Polysaccharides/chemistry , Polysaccharides/isolation & purification , Rats , Rats, Sprague-Dawley , Sulfates/chemistry , Sulfates/isolation & purificationABSTRACT
The active sulfated polysaccharide from seaweed possesses important pharmaceutical and biomedical potential. In the study, Monostroma sulfated polysaccharide (MSP) was obtained from Monostroma angicava, and the low-molecular-weight fragments of MSP (MSP-Fs: MSP-F1â»MSP-F6) were prepared by controlled acid degradation. The molecular weights of MSP and MSP-F1â»MSP-F6 were 335 kDa, 240 kDa, 90 kDa, 40 kDa, 24 kDa, 12 kDa, and 6.8 kDa, respectively. The polysaccharides were sulfated rhamnans that consisted of â3)-α-l-Rhap-(1â and â2)-α-l-Rhap-(1â units with partial sulfation at C-2 of â3)-α-l-Rhap-(1â and C-3 of â2)-α-l-Rhap-(1â. Anticoagulant properties in vitro of MSP and MSP-F1â»MSP-F6 were evaluated by studying the activated partial thromboplastin time, thrombin time, and prothrombin time. Anticoagulant activities in vivo of MSP and MSP-F4 were further evaluated; their fibrin(ogen)olytic activities in vivo and thrombolytic properties in vitro were also assessed by D-dimer, fibrin degradation products, plasminogen activator inhibitior-1, and clot lytic rate assays. The results showed that MSP and MSP-F1â»MSP-F4 with molecular weights of 24â»240 kDa had strong anticoagulant activities. A decrease in the molecular weight of MSP-Fs was accompanied by a decrease in the anticoagulant activity, and higher anticoagulant activity requires a molecular weight of over 12 kDa. MSP and MSP-F4 possessed strong anticoagulant activities in vivo, as well as high fibrin(ogen)olytic and thrombolytic activities. MSP and MSP-F4 have potential as drug or helpful food supplements for human health.
Subject(s)
Anticoagulants/pharmacology , Chlorophyta/chemistry , Deoxy Sugars/pharmacology , Fibrinolytic Agents/pharmacology , Mannans/pharmacology , Seaweed/chemistry , Acids/chemistry , Animals , Anticoagulants/chemistry , Anticoagulants/isolation & purification , Blood Coagulation Tests , Deoxy Sugars/chemistry , Deoxy Sugars/isolation & purification , Dietary Supplements , Fibrinolytic Agents/chemistry , Fibrinolytic Agents/isolation & purification , Humans , Male , Mannans/chemistry , Mannans/isolation & purification , Molecular Weight , Rats , Rats, Sprague-Dawley , Spectrum Analysis/methods , Sulfates/chemistryABSTRACT
Polysaccharide from Monostroma latissimum PML is a sulfated rhamnan, which consists of â3)-α-L-Rhap-(1â and â2)-α-L-Rhap-(1â residues with partial branches and sulfate groups at C-2 of â3)-α-L-Rhap-(1â and/or C-3 of â2)-α-L-Rhap-(1â. The anti-enterovirus 71 (EV71) activity in vitro of PML was assessed by cytopathic effect inhibition and plaque reduction assays, and the results showed that PML was non-cytotoxic and significantly inhibited EV71 infection. The mechanism analysis of anti-EV71 activity demonstrated that PML largely inhibited viral replication before or during viral adsorption, mainly by targeting the capsid protein VP1. PML may also inhibit some early steps of infection after viral adsorption by modulating signaling through the epidermal growth factor receptor (EGFR)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway. Moreover, PML markedly improved survival and decreased viral titers in EV71-infected mice. The investigation revealed that PML has potential as a novel anti-EV71 agent targeting the viral capsid protein as well as cellular EGFR/PI3K/Akt pathway.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Chlorophyta/chemistry , Deoxy Sugars/chemistry , Deoxy Sugars/pharmacology , Enterovirus A, Human/drug effects , Mannans/chemistry , Mannans/pharmacology , Sulfates/chemistry , Animals , Antiviral Agents/isolation & purification , Carbohydrate Sequence , Chlorocebus aethiops , Deoxy Sugars/isolation & purification , Enterovirus A, Human/physiology , Mannans/isolation & purification , Mice , Vero Cells , Viral Load/drug effectsABSTRACT
Great diversity and metabolite complexity of seaweeds offer a unique and exclusive source of renewable drug molecules. Polysaccharide from seaweed has potential as a promising candidate for marine drug development. In the present study, seaweed polysaccharide (SPm) was isolated from Monostroma angicava, the polymeric repeat units and anticoagulant property in vitro and in vivo of SPm were investigated. SPm was a sulfated polysaccharide which was mainly constituted by 3-linked, 2-linked-α-l-rhamnose residues with partially sulfate groups at C-2 of 3-linked α-l-rhamnose residues and C-3 of 2-linked α-l-rhamnose residues. Small amounts of xylose and glucuronic acid exist in the forms of ß-d-Xylp(4SO4)-(1â and ß-d-GlcA-(1â. SPm effectively prolonged clotting time as evaluated by the activated partial thromboplastin time and thrombin time assays, and exhibited strong anticoagulant activity in vitro and in vivo. The fibrin(ogen)olytic and thrombolytic properties of SPm were evaluated by plasminogen activator inhibitior-1, fibrin degradation products, D-dimer and clot lytic rate assays using rats plasma, and the results showed that SPm possessed high fibrin(ogen)olytic and thrombolytic properties. These results suggested that SPm has potential as a novel anticoagulant agent.
Subject(s)
Anticoagulants/pharmacology , Deoxy Sugars/chemistry , Mannans/chemistry , Seaweed/chemistry , Sulfates/chemistry , Animals , Chlorophyta/chemistry , Fibrinolytic Agents/pharmacology , Male , Partial Thromboplastin Time/methods , Plasminogen Activator Inhibitor 1/pharmacology , Polysaccharides/pharmacology , Rats , Rats, Sprague-Dawley , Thrombin Time/methods , Thrombosis/drug therapyABSTRACT
A sulfated polysaccharide, designated MAP2, was isolated from Monostroma angicava by water extraction, anion-exchange and size-exclusion chromatography. The structural characteristics of MAP2 were investigated by chemical and spectroscopic methods, including methylation analysis, one- and two-dimensional nuclear magnetic resonance and electrospray mass spectrometry with collision-induced dissociation spectroscopic analyses. The results showed that MAP2 was primarily composed of rhamnose with small amounts of xylose, glucuronic acid and glucose. The molecular weight of MAP2 was estimated to be about 671â¯kDa. The backbone of MAP2 was mainly constituted by 3-linked, 2-linked-á-l-rhamnose residues. Sulfate substitutions were at C-2/C-4 of 3-linked-á-l-rhamnose and C-3/C-4 of 2-linked-á-l-rhamnose residues. The branches consisted of 3-linked and 2-linked-á-l-rhamnose with monosulfate/unsulfate, as well as small amounts of ß-d-GlcA-(1â and ß-d-GlcA (2SO4)-(1â¯ââ¯. Minor amounts of â4)-d-Glcp-(1â and ß-d-Xylp (4SO4)-(1â might also be existent in MAP2. The investigation demonstrated that MAP2 was a novel sulfated rhamnan distinguishing from other algal sulfated rhamnans.