Isolation and Characterization of a Heparin-Like Compound with Potent Anticoagulant and Fibrinolytic Activity from the Clam Coelomactra antiquata

Anticoagulant and Fibrinolytic Properties of Two Heparinoid Compounds Prepared from Shrimp Waste

Heparinoid, a type of compound that has structures similar to heparin, has been found in marine organisms such as shrimp head. This shrimp waste products were used to prepare, characterize, and evaluate the antithrombotic effect of heparinoid. Two heparinoid compounds were obtained from shrimp head, and the main fraction F1 was →4)-GlcA-(1→3)-GalNAc-(1→ with Ara, while the minor fraction F2 composed mainly of the backbone as →4)-β-D-GlcA (or IdoA)-(1→4)-β-D-GlcN (or GlcNAc)-(1→. Both F1 and F2 could extend activated partial thromboplastin time and thrombin time concentration-dependently, and F2 has stronger activity than F1 at the same concentration. The potential anticoagulant mechanism of F1 and F2 may relate to their combination with more antithrombin III, which binds to and potentiates the action of antithrombin as well as inhibiting coagulation factors Xa and IIa, preventing blood clot formation. Furthermore, heparinoid F1 and F2 were found to have high fibrinolytic capability in vitro and in vivo via activating the self-fibrinolytic system. In conclusion, heparinoids (F1 and F2) derived from shrimp head wastes could be used as candidate compounds to prevent thrombosis while posing a lower hemorrhagic risk.

A natural heparinoid from mollusc Meretrix lusoria: Purification, structural characterization, and antithrombotic evaluation

Heparinoid, a sulfate polysaccharide derived from marine organisms was attracted largely attention due to its versatile activities. A naturally occurring heparinoid (M2) that was extracted from the mollusk Meretrix lusoria and used in this investigation shown strong antithrombotic action. UV-Vis, FT-IR, SAX-HPLC, and NMR were used to explore the structural characteristics of M2, results indicated that M2 similar with heparin, its average molecular weight was 22.58 kDa. Which was primarily made up of→4)-α-IdoA2S-(1→4)-α-GlcNS6S-(1→ (31.19%), →4)-β-GlcA-(1→4)-α-GlcNAc (1→ (23.21%), →4)-β-GlcA-(1→4)-α-GlcNS (1→ (13.87%), →4)-α-IdoA2S-(1→4)-α-GlcNS (1→ (8.95%), →4)-β-GlcA-(1→4)-α-GlcNAc6S (1→ (7.39%) and →4)-β-GlcA-(1→4)-α-GlcNS6S (1→ (7.63%). The antithrombotic activity of M2 was evaluated using measurements of the anticoagulant effect in vitro and the fibrinolytic capability in vitro and in vivo, and M2 has 122.4 U/mg of anticoagulant activity and 1.41 U/mg of fibrinolytic activity, respectively. Additionally, a mouse tail-cutting model was used to assess the bleeding effect in real time, it found that M2 had a reduced hemorrhagic risk than heparin. Consequently, M2 could be exploited to develop functional foods or medications with antithrombotic properties.

Chitosan/Alginate Nanoparticles for the Enhanced Oral Antithrombotic Activity of Clam Heparinoid from the Clam Coelomactra antiquata

Chitosan/alginate nanoparticles (DG1-NPs and DG1/Cur-NPs) aiming to enhance the oral antithrombotic activity of clam heparinoid DG1 were prepared by ionotropic pre-gelation. The influence of parameters, such as the concentration of sodium alginate (SA), chitosan (CTS), CaCl2, clam heparinoid DG1, and curcumin (Cur), on the characteristics of the nanoparticles, were investigated. Results indicate that chitosan and alginate can be used as polymer matrices to encapsulate DG1, and nanoparticle characteristics depend on the preparation parameters. Nano-particles should be prepared using 0.6 mg/mL SA, 0.33 mg/mL CaCl2, 0.6 mg/mL CTS, 7.2 mg/mL DG1, and 0.24 mg/mL Cur under vigorous stirring to produce DG1-NPS and DG1/Cur-NPS with small size, high encapsulation efficiency, high loading capacity, and negative zeta potential from approximately −20 to 30 mV. Data from scanning electron microscopy, Fourier-transform infrared spectrometry, and differential scanning calorimetry analyses showed no chemical reaction between DG1, Cur, and the polymers; only physical mixing. Moreover, the drug was loaded in the amorphous phase within the nanoparticle matrix. In the acute pulmonary embolism murine model, DG1-NPs enhanced the oral antithrombotic activity of DG1, but DG1/Cur-NPs did not exhibit higher antithrombotic activity than DG1-NPs. Therefore, the chitosan/alginate nanoparticles enhanced the oral antithrombotic activity of DG1, but curcumin did not further enhance this effect.

Antithrombotic Activity of Heparinoid G2 and Its Derivatives from the Clam Coelomactra antiquata

Clam heparinoid G2 (60.25 kDa) and its depolymerized derivatives DG1 (24.48 kDa) and DG2 (6.75 kDa) prepared from Coelomactra antiquata have been documented to have excellent fibrinolytic and anticoagulant activity. In this study, to further explore the antithrombotic activity of G2, DG1 and DG2, azure A, sheep plasma, and clot lytic rate assays were used to determine their anticoagulant and thrombolytic activity in vitro. The results indicated that the anticoagulant titer of G2 was approximately 70% that of heparin and the thrombolytic activity of DG2 was greater than G2, DG1, and heparin activities. Moreover, in a carrageenan-induced venous thrombosis model, oral administration of G2 and DG1 each at 20 mg/kg and 40 mg/kg for 7 days significantly reduced blacktail thrombus formation, increased tissue-type plasminogen activator, fibrin degradation products, and D-dimer levels, decreased von Willebrand factor and thromboxane B2 levels, and restored phylum and genus abundance changes of intestinal bacteria. DG2 had no antithrombotic effect. At 20 mg/kg, G2, DG1, and heparin had comparable antithrombotic activities, and DG1 at 40 mg/kg had more muscular antithrombotic activity than G2. Thus, DG1 could be an antithrombotic oral agent owing to its more robust antithrombotic activity and lower molecular weight.

Polysaccharide from Patinopecten yessoensis Skirt Boosts Immune Response via Modulation of Gut Microbiota and Short-Chain Fatty Acids Metabolism in Mice

Polysaccharide from marine shellfish has various bioactivities. In this study, the effects of polysaccharide from Patinopecten yessoensis skirt (PS) on boosting immune response in mice were evaluated, and the potential mechanisms were explored. The results showed that PS administration effectively increased the serum IgG and IgM levels, implying that PS had immune response-boosting properties. Moreover, PS administration could modulate the composition of the gut microbiota, and significantly improve short-chain fatty acids (SCFAs) metabolism, especially butyrate metabolism. Of note, the expression of the Tlr2, Tlr7, MyD88, Tnfa, and Il1b genes in toll-like receptor (TLR) signaling pathway was significantly increased. In summary, PS could boost immune response by modulating the gut microbiota and SCFAs metabolism correlating with the activation of the TLR signaling pathway. Therefore, PS can be developed as a special ingredient for functional product.

Extraction, structural characterization, and antioxidant and immunomodulatory activities of a polysaccharide from Notarchus leachii freeri eggs

The crude polysaccharides (NLCEP) were extracted from Notarchus leachii freeri eggs strings by the saltextractionmethod. The extraction conditions were optimized using the single-factorexperimentmethod and response surface method (RSM). The results showed that the maximum extraction yield of NLCEP was obtained under the following conditions: NaCl solution concentration of 2.96 %, raw material to liquid ratio of 1: 40 g/mL, extraction time of 2 h and extraction temperature of 69 °C. A new novel pure polysaccharide fraction named as NLCEPs-1 was fractionated from NLCEP by using DEAE-Cellulose 52 and Sephadex G-100. Its structure and immunomodulatory and antioxidant activities were analyzed. The results exhibited that the molecular weight of NLCEPs-1 was 31.4 kDa and it was composed of rhamnose, glucose, galactose, xylose and arabinose in the molar percentage of 11.128: 63.770: 5.439: 6.585: 13.077. The backbone of NLCEPs-1 was mainly consisted of → )4-α-d-Glcp (1→, →6)-α-d-Glcp (1→, →1)-β-d-Galp and β-d-Galp-(1→. NLCEPs-1 exhibited the strong antioxidant activity in scavenging ability of various free radicals and immunomodulatory activity by the enhancement of the pinocytic capacity, nitric oxide (NO) and cytokines.

Anti-platelet Drug-loaded Targeted Technologies for the Effective Treatment of Atherothrombosis

Atherothrombosis results from direct interaction between atherosclerotic plaque and arterial thrombosis and is the most common type of cardiovascular disease. As a long term progressive disease, atherosclerosis frequently results in an acute atherothrombotic event through plaque rupture and platelet-rich thrombus formation. The pathophysiology of atherothrombosis involves cholesterol accumulation endothelial dysfunction, dyslipidemia, immuno-inflammatory, and apoptotic aspects. Platelet activation and aggregation is the major cause for stroke because of its roles, including thrombus, contributing to atherosclerotic plaque, and sealing off the bleeding vessel. Platelet aggregates are associated with arterial blood pressure and cardiovascular ischemic events. Under normal physiological conditions, when a blood vessel is damaged, the task of platelets within the circulation is to arrest the blood loss. Antiplatelet inhibits platelet function, thereby decreasing thrombus formation with complementary modes of action to prevent atherothrombosis. In the present scientific scenario, researchers throughout the world are focusing on the development of novel drug delivery systems to enhance patient's compliance. Immediate responding pharmaceutical formulations become an emerging trend in the pharmaceutical industries with better patient compliance. The proposed review provides details related to the molecular pathogenesis of atherothrombosis and recent novel formulation approaches to treat atherothrombosis with particular emphasis on commercial formulation and upcoming technologies.

Extraction, Characterization, and Anticoagulant Activity of a Sulfated Polysaccharide from Bursatella leachii Viscera

Bioactive compounds for drug discovery are increasingly extracted and purified from natural sources including marine organisms. Heparin is a therapeutic agent that has been used for several decades as an anticoagulant. However, heparin is known to cause many undesirable complications such as thrombocytopenia and risk of hemorrhage. Hence, there is a need to find alternatives to current widely used anticoagulant drugs. Here, we extract a sulfated polysaccharide from sea hare, that is, Bursatella leachii viscera, by enzymatic digestion. Several analytical approaches including elemental analysis, Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and high-performance liquid chromatography-mass spectrometry analysis show that B. leachii polysaccharides have chemical structures similar to glycosaminoglycans. We explore the anticoagulant activity of the B. leachii extract using the activated partial thromboplastin time and the thrombin time. Our results demonstrate that the extracted sulfated polysaccharide has heparin-like anticoagulant activity, thus showing great promise as an alternative anticoagulant therapy.