Preparation, characterization and in vitro anticoagulant activity of highly sulfated chitosan

Functionalized chitosan-inspired (nano)materials containing sulfonic acid groups: Synthesis and application

Nature-inspired chitosan (CS) materials show a high potential for the design/fabrication of sustainable heterogeneous (nano)materials with extraordinary structural/physical features, such as superior biodegradability/biocompatibility, simplicity of chemical modification, environmental safety, high availability, cost-effectiveness, high electrochemical activity, good film-forming ability, and antioxidant, antimicrobial/antibacterial, and anticoagulant activities. Industrialization and growth of industrial wastes or by-products induce an increasing demand for the development of clean, low-cost, and renewable natural systems to minimize or eliminate the utilization of environmentally toxic compounds. The preparation of novel heterogeneous functionalized polysaccharide-inspired bio(nano)materials via chemical modifications of natural CS to improve its physicochemical/biochemical properties has recently become tremendously attractive for many researchers. The most abundantly available and cost-effective functionalized CS-inspired (nano)materials are considerably valuable in terms of the economic aspects of production of (nano)catalysts, (nano)hydrogels, (nano)composite/blend membranes, and thus their commercialization. In this respect, the preparation of functionalized CS-inspired (nano)materials containing -SO3H groups has been represented as a valid alternative to the homogenous unmodified biomaterials for various applications. Sulfonated derivatives of CS-inspired (nano)materials may possess huge surface areas, catalytic activity, adsorption, and biological/biomedical properties. This review article is aimed at the investigation of different methods and potential applications of sulfonated CS-inspired (nano)materials in catalysis, fuel cells, adsorption of ions, membranes, and biological applications.

Chemical modification of bacterial exopolysaccharides: Antioxidant properties and health potentials

In recent years, there has been a burgeoning interest in the utilization of microbial exopolysaccharides (EPS) because of the added advantage of their renewable, biocompatible, and biodegradable nature in addition to intended applications. The endowed properties of bacterial EPS make them valuable candidates for a wide array of industrial applications. Modification of native EPS is known to enhance various physico-chemical and functional properties. Various modifications such as physical, chemical, biological, and enzymatic modifications were practiced improving the bioactivity of EPS. This paper comprehensively aims to review the most recent chemical modification techniques employed to modify the physico-chemical and functional changes of bacterial EPS in comparison with the unmodified forms. Chemical modification entails strategic alterations to the structure and properties of EPS through various synthetic and semi-synthetic methodologies. Emphasis is given to the antioxidant potential and functional role of these EPS derivatives in human health. Antioxidant properties reveal a significant augmentation in activity compared to their native counterparts. Such enhancement holds a strong promise for potential benefits and therapeutic applications. Chemical derivatives of EPS with overwhelming functional benefits could surely encourage EPS application, particularly as potential hydrocolloids in industrial and biomedical contexts.

Anticoagulant Protective Effects of Sulfated Chitosan Derived From the Internal Bone of Spineless Cuttlefish (Sepiella inermis)

Background This study investigated the anticoagulant properties of sulfated chitosan derived from the internal bone of the spineless cuttlefish Sepiella inermis. Chitosan, a biopolymer, is used in various biomedical applications including anticoagulation. Sulfation of chitosan enhances its biological activity, making it a potential therapeutic agent. This study explored the efficacy of sulfated chitosan in preventing blood clot formation to provide a novel anticoagulant alternative. Objectives This study aimed to synthesize and characterize the anticoagulant properties of sulfated chitosan extracted from the internal bone of the spineless cuttlefish S. inermis using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and X-Ray Diffraction (XRD) and evaluate the anticoagulant properties of sulfated chitosan extracted from the internal bone of spineless cuttlefish S. inermis. Materials and methods Chitin and chitosan were extracted from the cuttlebone of a specimen of S. inermis, and sulfated chitosan was synthesized by sulfation of chitosan. Sulfated chitosan was subsequently used to evaluate its anticoagulant properties using tests such as activated partial thromboplastin time (APTT) and prothrombin time (PT). Characteristic investigations were conducted, including FTIR, FESEM, and XRD analyses. Results The results of this study suggested the possibility of using S. inermis internal bone as an unconventional source of natural anticoagulant that can be combined with biomedical applications. Anticoagulant activity measured using APTT and PT showed that sulfated chitosan was a strong anticoagulant. Conclusion We examined the anticoagulant activity of S. inermis extract using thrombin and activated partial thromboplastin times. Our results demonstrated the heparin-like anticoagulant action of the extracted sulfated chitosan, suggesting that it may be a great alternative anticoagulant treatment.

Sulfation of furcellaran and its effect on hemocompatibility in vitro

In this study, furcellaran (FUR) obtained from Furcellaria lumbricalis was firstly employed for sulfation via various methods, including SO3-pyridine (SO3∙Py) complex in different aprotic solvents, chlorosulfonic acid and sulfuric acid with a "coupling" reagent N,N'-Dicyclohexylcarbodiimide. Structural characterization through FT-IR, GPC, XPS and elemental analyses confirmed the successful synthesis of 6-O-sulfated FUR derivates characterized by varying degrees of sulfation (DS) ranging from 0.15 to 0.91 and molecular weight (Mw) spanning from12.5 kDa to 2.7 kDa. In vitro clotting assays, partial thromboplastin time (aPTT), thrombin time (TT), and prothrombin time (PT) underscored the essential role of sulfate esters in conferring anticoagulant activity whereas FUR prepared via chlorosulfonic acid with DS of 0.91 reached 311.4 s in aPPT showing almost 4-fold higher anticoagulant activity than native FUR at the concentration 2 mg/mL. MTT test showed all tested samples decreased cell viability in a dose dependent manner while all of them are non-cytotoxic up to the concentration of 0.1 mg/mL. Furthermore, sulfated derivates deposited onto polyethylene terephthalate surface presented substantial decrease in platelet adhesion, as well as absence of the most activated platelet stages. These findings support the pivotal role of O-6 FUR sulfates in enhancing hemocompatibility and provide valuable insights for a comparative assessment of effective sulfating approaches.

Research progress on ginger polysaccharides: extraction, purification and structure-bioactivity relationship

Ginger is a widespread source of herbal medicine and traditional spices. Among its various bioactive components, ginger polysaccharides (GPs) have attracted the attention of researchers worldwide because of their significant bioactivity. Recent studies have demonstrated the antioxidant, antitumour, anti-inflammatory, immunomodulatory, hypoglycaemic, cough suppressant and thrombotic anticoagulant effects of GPs. However, the structure-bioactivity relationship of GPs has yet to be comprehensively investigated. This review aims to explore all the current published studies on GPs. It further examines various aspects, including the extraction and purification methods, structure, bioactivity, application and structure-bioactivity relationship of GPs. Thus, this review intends to provide a reference for future GP-related research and development.

New N-Methylimidazole-Functionalized Chitosan Derivatives: Hemocompatibility and Antibacterial Properties

Novel imidazole derivatives of the low molecular weight chitosan N-(2-hydroxypropyl)-1H-1,2,3-triazol-4-yl)methyl)-1-methyl-1H-imidazol-3-ium chitosan chloride (NMIC) were synthesized using copper-catalyzed azide-alkyne cycloaddition (CuAAC). The degrees of substitution (DSs) for the new derivatives were 18-76%. All chitosan derivatives (2000 µg/mL) were completely soluble in water. The antimicrobial activity of the new compounds against E. coli and S. epidermidis was studied. The effect of chitosan derivatives on blood and its components was studied. NMIC samples (DS 34-76%) at a concentration <10 μg/mL had no effect on blood and plasma coagulation. Chitosan derivatives (DS 18-76%) at concentrations of ≥83 μg/mL in blood and ≥116.3 μg/mL in plasma resulted in a prolongation of the clotting time of blood and plasma, positively related to the DS. At concentrations up to 9.1 μg/mL, NMIC did not independently provoke platelet aggregation. The degree of erythrocyte hemolysis upon contact with NMIC samples (2.5-2500 μg/mL) was below 4%. The inhibition of blood/plasma coagulation indicates the promising use of the studied samples to modify the surface of medical materials in order to achieve thromboresistance.

Anti-COVID-19 Credentials of Chitosan Composites and Derivatives: Future Scope?

Chitosan derivatives and composites are the next generation polymers for biomedical applications. With their humble origins from the second most abundant naturally available polymer chitin, chitosan is currently one of the most promising polymer systems, with wide biological applications. This current review gives a bird’s eye view of the antimicrobial applications of chitosan composites and derivatives. The antiviral activity and the mechanisms behind the inhibitory activity of these components have been reviewed. Specifically, the anti-COVID-19 aspects of chitosan composites and their derivatives have been compiled from the existing scattered reports and presented. Defeating COVID-19 is the battle of this century, and the chitosan derivative-based combat strategies naturally become very attractive. The challenges ahead and future recommendations have been addressed.

Evaluation of chitosan salt properties in the production of AgNPs materials with antibacterial activity

In this study, water-soluble chitosan salts (chitosan amine sulfopropyl salts) were prepared from chitosan samples with different molecular weights and deacetylation degrees. These soluble-in-water polymer salts allowed us to produce, in an eco-friendly and facile method, silver nanoparticles (AgNPs) with better control on size and polydispersity, even at large silver concentrations than their corresponding chitosan sample. Chitosan salt-based materials (films and scaffolds) were analyzed in terms of antibacterial properties against Staphylococcus aureus ATCC23915 or Pseudomonas aeruginosa ATCC 27853. 3D scaffolds enhanced the effect of the chitosan-AgNPs combination compared to the equivalent films.

Marine Biological Macromolecules and Chemically Modified Macromolecules; Potential Anticoagulants

Coagulation is a potential defense mechanism that involves activating a series of zymogens to convert soluble fibrinogen to insoluble fibrin clots to prevent bleeding and hemorrhagic complications. To prevent the extra formation and diffusion of clots, the counterbalance inhibitory mechanism is activated at levels of the coagulation pathway. Contrariwise, this system can evade normal control due to either inherited or acquired defects or aging which leads to unusual clots formation. The abnormal formations and deposition of excess fibrin trigger serious arterial and cardiovascular diseases. Although heparin and heparin-based anticoagulants are a widely prescribed class of anticoagulants, the clinical use of heparin has limitations due to the unpredictable anticoagulation, risk of bleeding, and other complications. Hence, significant interest has been established over the years to investigate alternative therapeutic anticoagulants from natural sources, especially from marine sources with good safety and potency due to their unique chemical structure and biological activity. This review summarizes the coagulation cascade and potential macromolecular anticoagulants derived from marine flora and fauna.

Regioselective sulfated chitosan produces a biocompatible and antibacterial wound dressing with low inflammatory response

The aim of current study is to tailor chitosan derivate which is water-soluble while presents original biological features of chitosan. For this purpose, the 6-O chitosan sulfate (CS) with naked amine groups was synthesized via regioselective modification of chitosan (C) during which both crosslinking capacity and antibacterial properties of the C were remained intact. This was achieved by sulfation the C under controlled acidic conditions using chlorosulfonic acid/sulfuric acid mixture. Subsequently, a chemically crosslinked hydrogel of the CS was used as a wound dressing substrate. The modified sulfate groups retained the biocompatibility of C and showed antibacterial effects against gram-positive and gram-negative bacteria. In addition, the presence of sulfate groups in the CS chemical structure improved its anticoagulant activity compared to the unmodified C. Both in vitro and in vivo enzyme-linked immunosorbent assay (ELISA) measurements showed that CS had a higher potential to bind and scavenger anti-inflammatory cytokines, including IL-6 and transforming growth factor-β (TGF-β), both of which play critical roles in the early stage of the wound healing process. After treatment of full-thickness wounds with CS hydrogels, the macrophage cells (c.a. 6 × 10⁴ cells) expressed significantly more M2 phenotype markers compared to the C group (4.2 × 10⁴ cells). Furthermore, the CS hydrogel induced better re-epithelialization and vascularization of full-thickness wounds in mice compared to the C hydrogel during 30 days.

Is It an Outbreak of Health Care-Associated Infection? An Investigation of Binocular Conjunctival Congestion After Laparoscopic Cholecystectomy Was Traced to Chitosan Derivatives

Background

From May 6 to May 23, 2019, 24 (80.00%) patients who underwent laparoscopic cholecystectomy (LC) developed binocular conjunctival congestion within 4–8 h after their operation in the day ward of a teaching hospital.

Methods

Nosocomial infection prevention and control staff undertook procedural and environmental investigations, performed a case-control retrospective study (including 24 cases and 48 controls), and reviewed all lot numbers of biological material products to investigate the suspected outbreak of health care-associated infection.

Findings

Initially, an outbreak of health care-associated infection caused by bacteria was hypothesized. We first suspected the membranes that covered patients' eyes were cut using non-sterile scissors and thus contaminated, but they failed to yield bacteria. In addition, both corneal and conjunctival fluorescein staining results were negative in case-patients and isolated bacteria were ubiquitous in the environment or common skin commensals or normal flora of conjunctiva from 218 samples from day surgery and the day ward. Hence, we considered a non-infectious factor as the most likely cause of the binocular conjunctival congestion. Then, we found that case-patients were more likely than LC surgery patients without binocular conjunctival congestion to be exposed to biological materials in a retrospective case-control study. When we reviewed lot numbers, duration of use, and the number of patients who received four biological material products during LC in the day ward, we found that the BLK1821 lot of a modified chitosan medical membrance (the main ingredient is chitosan, a linear cationic polysaccharide) was used concurrently to when the case aggregation appeared. Finally, we surmised there was a correlation between this product and the outbreak of binocular conjunctival congestion. Relapse of the pseudo-outbreak has not been observed since stopping usage of the product for 6 months.

Conclusion

A cluster of binocular non-infectious conjunctival congestion diagnosed after LC proved to be a pseudo-outbreak. We should pay more attention to adverse events caused by biomaterials in hospitals.

Low molecular weight sulfated chitosan isolation, characterization and anti-tuberculosis activity derived from Sepioteuthis lessoniana

The research focused on tuberculosis as it is one of the world's most serious health problems. The extracted chitin from the gladius of Sepioteuthis lessoniana converted into Chitosan (CH). The purified and freeze-dried CH was refined as Sulfated Chitosan (SCH). The SCH was converted into low molecular weight of SCH with various doses of Gamma Irradiation (GIR). Fluorescence characteristics of GIR-SCH and elemental analysis were confirmed. The structure and molecular weights of GIR-SCH were determined with FT-IR, NMR and MALDI-TOF/Mass Spectroscopy. 100 Gy of GIR-SCH significantly showed the minimum inhibitory concentration (MIC) against Mycobacterium smegmatis. The MIC against M. smegmatis was not affected by the varied sulfate levels in the identical molecular weight GIR-SCH. However, the lowest molecular weight GIR-SCH displayed a significantly MIC against M. smegmatis. In docking analysis, the 6ZT3 ligand had the lowest binding energy of -1.57 kcal/Mol indicating a superior binding interaction with GIR-SCH. The effect of molecular weight reduction by GIR on the anti-tuberculosis capacity of GIR SCH was investigated in this study which had antimicrobial implications.

Heparanized chitosans: towards the third generation of chitinous biomaterials

The functionalization of chitosans is an emerging research area in the design of solutions for a wide range of biomedical applications. In particular, the modification of chitosans to incorporate sulfate groups has generated great interest since they show structural similarity to heparin and heparan sulfates. Most of the biomedical applications of heparan sulfates are derived from their ability to bind different growth factors and other proteins, as through these interactions they can modulate the cellular response. This review aims to summarize the most recent advances in the synthesis, and structural and physicochemical characterization of heparanized chitosan, a remarkably interesting family of polysaccharides that have demonstrated the ability to mimic heparan sulfates as ligands for different proteins, thereby exerting their biological activity by mimicking the function of these glycosaminoglycans.

Underscoring the immense potential of chitosan in fighting a wide spectrum of viruses: A plausible molecule against SARS-CoV-2?

Chitosan is a deacetylated polycationic polysaccharide derived from chitin. It is structurally constituted of N-acetyl-D-glucosamine and β-(1-4)-linked D-glucosamine where acetyl groups are randomly distributed across the polymer. The parameters of deacetylation and depolymerization process greatly influence various physico-chemical properties of chitosan and thus, offer a great degree of manipulation to synthesize chitosan of interest for various industrial and biomedical applications. Chitosan and its various derivatives have been a potential molecule of investigation in the area of anti-microbials especially anti-fungal, anti-bacterial and antiviral. The current review predominantly highlights and discusses about the antiviral activities of chitosan and its various substituted derivatives against a wide spectrum of human, animal, plants and bacteriophage viruses. The extrinsic and intrinsic factors that affect antiviral efficacy of chitosan have also been talked about. With the rapid unfolding of COVID-19 pandemic across the globe, we look for chitosan as a plausible potent antiviral molecule for fighting this disease. Through this review, we present enough literature data supporting role of chitosan against different strains of SARS viruses and also chitosan targeting CD147 receptors, a novel route for invasion of SARS-CoV-2 into host cells. We speculate the possibility of using chitosan as potential molecule against SARS-CoV-2 virus.

Chitosan-Based Nanoparticles Against Viral Infections

Viral infections, in addition to damaging host cells, can compromise the host immune system, leading to frequent relapse or long-term persistence. Viruses have the capacity to destroy the host cell while liberating their own RNA or DNA in order to replicate within additional host cells. The viral life cycle makes it challenging to develop anti-viral drugs. Nanotechnology-based approaches have been suggested to deal effectively with viral diseases, and overcome some limitations of anti-viral drugs. Nanotechnology has enabled scientists to overcome the challenges of solubility and toxicity of anti-viral drugs, and can enhance their selectivity towards viruses and virally infected cells, while preserving healthy host cells. Chitosan is a naturally occurring polymer that has been used to construct nanoparticles (NPs), which are biocompatible, biodegradable, less toxic, easy to prepare, and can function as effective drug delivery systems (DDSs). Furthermore, chitosan is Generally Recognized as Safe (GRAS) by the US Food and Drug Administration (U.S. FDA). Chitosan NPs have been used in drug delivery by the oral, ocular, pulmonary, nasal, mucosal, buccal, or vaginal routes. They have also been studied for gene delivery, vaccine delivery, and advanced cancer therapy. Multiple lines of evidence suggest that chitosan NPs could be used as new therapeutic tools against viral infections. In this review we summarize reports concerning the therapeutic potential of chitosan NPs against various viral infections.

Exploiting the Amazing Diversity of Natural Source-Derived Polysaccharides: Modern Procedures of Isolation, Engineering, and Optimization of Antiviral Activities

Naturally occurring polysaccharide sulfates are highly diverse, owning variations in the backbone structure, linkage pattern and stereochemistry, branching diversity, sulfate content and positions of sulfate group(s). These structural characteristics bring about diverse sulfated polymers with dissimilar negative charge densities and structure-activity relationships. Herein, we start with a short discussion of techniques needed for extraction, purification, chemical sulfation, and structural characterization of polysaccharides. Processes of isolation and sulfation of plant-derived polysaccharides are challenging and usually involve two steps. In this context, we describe an integrated extraction-sulfation procedure that produces polysaccharide sulfates from natural products in one step, thereby generating additional pharmacological activities. Finally, we provide examples of the spectrum of natural source-derived polysaccharides possessing specific features of bioactivity, in particular focusing on current aspects of antiviral drug development and drug-target interaction. Thus, the review presents a detailed view on chemically engineered polysaccharides, especially sulfated derivatives, and underlines their promising biomedical perspectives.

Sulfation, structural analysis, and anticoagulant bioactivity of ginger polysaccharides

In this study, ginger polysaccharide (GP), ginger polysaccharide 1 (GP1), and ginger polysaccharide 2 (GP2) from ginger were firstly modified by sulfation. Fourier transform infrared, and nuclear magnetic resonance spectra investigation of sulfated ginger polysaccharide (SGP), sulfated ginger polysaccharide 1 (SGP1), and sulfated ginger polysaccharide 2 (SGP2) revealed that the sulfation successfully occurred with the characteristic absorption peak of polysaccharide. Congo red experiment showed that triple helical structure existed in SGP and SGP1, but random coils existed in SGP2. SGP, SGP1, and SGP2 all showed a rough and rugged surface with plenty of small pores. The blood clotting time of SGP2 or SGP at 2 mg/mL in activated partial thromboplastin time (APTT) assay was 41.42 or 38.01 s, respectively, which were approximately 1.33- and 1.22-fold longer than that of the physiological saline. Compared to the saline control group, prothrombin time (PT) was increased by 1.22-fold with the addition of GP at 2 mg/mL. However, no clotting inhibition phenomenon was observed in thrombin time test even at the concentrations that APTT and PT were obviously prolonged. It indicated that GP2, SGP2, and SGP inhibited the intrinsic pathway of coagulation, but GP inhibited both the intrinsic and extrinsic pathways of coagulation. Hence, ginger polysaccharides might be used as anticoagulants and therapeutic reagents for thrombosis.

Antibacterial, anticoagulant and cytotoxic evaluation of biocompatible nanocomposite of chitosan loaded green synthesized bioinspired silver nanoparticles

Present work reports the green synthesis of chitosan functionalized silver nanoparticles (CS-AgNPs) using ethanolic buds extract of Sygyzium aromaticum. CS-AgNPs were characterized physically, evaluated for antibacterial, anticoagulant and antiplatelet activities, and toxicity profile. The physical characterization of CS-AgNPs was done by UV/vis, SEM, TEM, FTIR and EDX. The sphericity was found uniform. FTIR and EXD showed noninterfering few impurities. The antibacterial activity against VRSA (ZI, 23.2 ± 0.51 mm) and MRSA (ZI, 25.8 ± 0.32 mm) were determined. The rise in bleeding and thromboplastin was observed highly significant while increased in prothrombin and activated partial prothrombin time in significant manner at both the doses of CS-AgNPs (0.025 mg/kg and 0.05 mg/kg). Reduction in the levels of fibrinogen was also highly significant. Platelet aggregation decreased at high dose of CS-AgNPs i.e. 55.14 ± 8.25% (arachidonic acid) and 13.06 ± 2.17% (collagen). Thrombin antithrombin (TAT) complex activity was found highest for CS-AgNPs. Cytotoxicity was assessed using HeLa cell lines (LC₅₀; 125 μg/ml) and brine shrimp lethality tests (LC_50; 518 μg/ml). The work suggests that green synthesized chitosan functionalized silver nanoparticles may be utilized as an effective antibacterial agent and anticoagulant with low toxicity. The current findings will open a new window for nanomedicine development and future clinical application.

Aquaculture and its by-products as a source of nutrients and bioactive compounds

Underutilized marine resources (e.g., algae, fish, and shellfish processing by-products), as sustainable alternatives to livestock protein and interesting sources of bioactive compounds, have attracted the attention of the researchers. Aquatic products processing industries are growing globally and producing huge amounts of by-products that often discarded as waste. However, recent studies pointed out that marine waste contains several valuable components including high-quality proteins, lipids, minerals, vitamins, enzymes, and bioactive compounds that can be used against cancer and some cardiovascular disorders. Besides, previously conducted studies on algae have shown the presence of some unique biologically active compounds and valuable proteins. Hence, this chapter points out recent advances in this area of research and discusses the importance of aquaculture and fish processing by-products as alternative sources of proteins and bioactive compounds.

Synthesis, characterization and anticoagulant activity of chitosan derivatives

Chitosan derivatives are reported as anticoagulants in the literature. This work was undertaken to develop novel chitosan derivatives as anticoagulants. The sulfonated derivatives of chitosan were formed by the reaction of chitosan derivatives with chlorosulfonic acid in N,N-dimethylformamide. The structures of these derivatives were established by FTIR and ¹H NMR spectra. The prepared derivatives were evaluated for their in vivo anticoagulant effects by the tail bleeding method in Wistar rats utilizing nicoumalone as a standard drug. The results revealed that the sulfonation of the chitosan increases its anticoagulant activity. The developed compounds exhibited faster onset of action and potency than nicoumalone after one hour of the drug administration. The sulphated N-alkyl derivatives of chitosan were more potent anticoagulants than sulfated quaternary derivatives/sulfated chitosan. It is also suggested to develop analogs of Ethyl chitosan sulfate (4b) and Benzyl chitosan sulfate (4c), which may provide some more fruitful anticoagulants having faster onset of action as well as longer duration of action and possessing a balanced hydrophilic/lipophilic character.

Chemical composition, structural features, surface morphology and bioactivities of chitosan derivatives from lobster (Thenus unimaculatus) shells

The chemical composition, structural features and bioactivities of chitosan derivatives were studied and reported here. Chitin and chitosan was extracted by chemical methods and yield was recorded 35% and 41%, moisture and ash has showed 7.4, 0.73, 1.2 and 0.79% and Ca was recorded high level (590 ppm). The IR spectrum has showed NH primary and secondary amines, OH group and several sugar stretching. N-acetyl glucosamine (GlcNAc), H-2 proton of glucosamine (GlcN), Anomeric protons, H-1 [GlcN (H-1D), GlcNAc (H-1A)] were noticed in ¹H NMR and anomeric, methyl carbon atoms in ¹³C NMR. Rough surface, irregular block, crystalline with cluster and porosity structure was noticed by SEM observation. Antioxidant effect has showed good and concentration depended in four antioxidant assays. The α-amylase and β-glucosidase enzyme inhibition effect of chitosan has showed promising and dose depend also anticoagulant potential. Chitosan could be used in pharmaceutical industry and tissue engineering.

The inhibitory effects and mechanisms of 3,6-O-sulfated chitosan against human papillomavirus infection

High-risk human papillomavirus (HPV) infection can lead to the development of cervical cancers that are a significant health burden worldwide. The heparin-like polysaccharides such as dextran sulfate and carrageenan were reported to be able to prevent the binding of HPV to the cell surface. In this study, a 3,6-O-sulfated chitosan (36S) was prepared, and its anti-HPV effects were explored. The results showed that 36S effectively inhibited multiple genital HPV genotypes in different cell lines with low cytotoxicity. 36S may possibly block HPV adsorption via direct binding to the viral capsid proteins. 36S could enter into Hela cells and down-regulate cellular PI3K/Akt/mTOR pathway which is associated with autophagy. Thus, marine derived sulfated chitosan 36S possessed broad anti-HPV activities in vitro, and may possibly inhibit HPV infection by targeting viral capsid protein and host PI3K/Akt/mTOR pathway, suggesting that 36S merits further investigation as a novel anti-HPV agent.

Antioxidant Activity and Antifungal Activity of Chitosan Derivatives with Propane Sulfonate Groups

We successfully synthesized the water-soluble chitosan derivatives propane sulfonated chitosan (PSCS) and dipropane sulfonated chitosan (DPSCS) in this paper. These derivatives were characterized by FTIR, ¹H NMR, and 13C NMR. Moreover, the antioxidant activity of the chitosan derivatives was evaluated by free radical scavenging ability (against DPPH-radical, hydroxyl-radical, and superoxide-radical) and ferric reducing power. Meanwhile, inhibitory effects against two fungi were also tested. Our results suggested antioxidant abilities and antifungal properties were in order of DPSCS > PSCS > CS, which were consistent with the number of propane sulfonated groups. The scavenging activity of DPSCS against superoxide-radical and DPPH-radical were 94.1% and 100% at 1.6 mg/mL, respectively. The inhibitory indices of DPSCS against P. asparagi and F. oxysporum were up to 82.2% and 94% at 1.0 mg/mL, respectively. Obviously, the number of propane sulfonated groups of chitosan derivatives not only contributes to antioxidant activity, but also to antifungal activity. Therefore, DPSCS with more propane sulfonated groups endowed with antioxidant and antifungal activity that can be used as a candidate material in the food and pharmaceutical industries.

Heparin mimetics with anticoagulant activity

Heparin, a sulfated polysaccharide belonging to the glycosaminoglycan family, has been widely used as an anticoagulant drug for decades and remains the most commonly used parenteral anticoagulant in adults and children. However, heparin has important clinical limitations and is derived from animal sources which pose significant safety and supply problems. The ever growing shortage of the raw material for heparin manufacturing may become a very significant issue in the future. These global limitations have prompted much research, especially following the recent well-publicized contamination scandal, into the development of alternative anticoagulants derived from non-animal and/or totally synthetic sources that mimic the structural features and properties of heparin. Such compounds, termed heparin mimetics, are also needed as anticoagulant materials for use in biomedical applications (e.g., stents, grafts, implants etc.). This review encompasses the development of heparin mimetics of various structural classes, including synthetic polymers and non-carbohydrate small molecules as well as sulfated oligo- and polysaccharides, and fondaparinux derivatives and conjugates, with a focus on developments in the past 10 years.

Study on Brilliant Blue-chitosan System by Dual-wavelength Overlapping Resonance Rayleigh Scattering Method and its Analytical Applications

The method was presented for the sensitive and selective determination of chitosan (CTS) in health products with Brilliant Blue (BB) as a probe, based on dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS). In weakly acidic buffer solution, the binding of CTS and BB could result in the RRS intensities getting enhanced significantly at RRS peaks of 344nm and 452nm, and the scattering intensities of the two peaks were proportional to the concentration of CTS within a certain range. When the RRS intensities of the two wavelengths were superposed, the results showed higher sensitivity. Under the optimum experimental conditions, the total of the two increased RRS intensities was linear to the CTS concentration in the range of 0.02-1.80μg/mL and the limit of detection (LOD) was 7.45ng/mL. In this work, the optimum conditions and the effects of some foreign substances were studied. Accordingly, the new method based on DWO-RRS for the determination of CTS was developed. In addition, the effect of the molecular weight and the deacetylation degree between different chitosan molecules was discussed. Finally, this assay was applied to determine the concentration of CTS in health products with satisfactory results.

Preparation and in vitro antioxidant activities of 6-amino-6-deoxychitosan and its sulfonated derivatives

The 6-amino-6-deoxychitosan (NC) and their 2, 6-di-N-sulfonated derivatives were prepared via N-phthaloylation, tosylation, azidation, hydrazinolysis, reduction of azide groups and N-sulfonation, and their structures were systematically characterized by FT-IR, 2D HSQC NMR, XRD, gel permeation chromatography (GPC), and elemental analysis. The 6-amino-6-deoxychitosan showed effect in three selected antioxidant essays, including reducing power, superoxide anion radical scavenging ability, and hydroxyl radical scavenging effect. But the factors affecting each activity were different. The reducing power and the superoxide anion radical scavenging ability of NC were strong and closely related to the amino groups in the molecular chains. Both introducing N-sulfonated groups into NC and the concentration reduction of NC and its sulfonated derivatives decreased these activities. For the superoxide anion radical, the molecular charge property was also a significant influence factor. For the hydroxyl radical, NC only showed weak scavenging activity in a special inverse concentration-dependent manner. However, the incorporation of N-sulfonated groups significantly improved the scavenging activity, and the more N-sulfonated groups, the higher the concentrations, the stronger the activity was. The results could be due to the different conformations of NC and its sulfonated derivatives in aqueous solution.

Polysaccharides from the Marine Environment with Pharmacological, Cosmeceutical and Nutraceutical Potential

Carbohydrates, also called saccharides, are molecules composed of carbon, hydrogen, and oxygen. They are the most abundant biomolecules and essential components of many natural products and have attracted the attention of researchers because of their numerous human health benefits. Among carbohydrates the polysaccharides represent some of the most abundant bioactive substances in marine organisms. In fact, many marine macro- and microorganisms are good resources of carbohydrates with diverse applications due to their biofunctional properties. By acting on cell proliferation and cycle, and by modulating different metabolic pathways, marine polysaccharides (including mainly chitin, chitosan, fucoidan, carrageenan and alginate) also have numerous pharmaceutical activities, such as antioxidative, antibacterial, antiviral, immuno-stimulatory, anticoagulant and anticancer effects. Moreover, these polysaccharides have many general beneficial effects for human health, and have therefore been developed into potential cosmeceuticals and nutraceuticals. In this review we describe current advances in the development of marine polysaccharides for nutraceutical, cosmeceutical and pharmacological applications. Research in this field is opening new doors for harnessing the potential of marine natural products.

The stimuli-response characters of hydrogels prepared using ultrasound

The present work was an attempt to investigate the parameters that can affect the process of hydrogel formation in the presence of ultrasound. These parameters were concentrations of the reactants, the reaction medium, and acoustic factors. The monomers were acrylic acid and acrylamide, and the cross-linker was methylene bis acrylamide. Pulsed power ultrasound was irradiated to the reaction mixture from the tip of a probe unit. The swelling behaviors of the obtained hydrogels were investigated in various buffer solutions, at different temperature values, and using different ionic salts. The results show that ultrasonic irradiation significantly reduces reaction time and increases efficiency. Additionally, increasing glycerol in the solution changes the viscosity of the reaction for the better and increases the reaction rate. However, ionic strength and pH were not significantly effective in this respect. Another major finding was that increasing ultrasonic power and pulse hastens the reaction. Cationic salts were effective in this order: Na+>Ca2+>Fe3+. The hydrogel was responsive to pH, temperature, and salts. These findings provide a better understanding of hydrogel synthesis and enable us to control the pertinent parameters.