Conductivity detection for molecular mass estimation of per-O-sulfonated glycosaminoglycans separated by high-performance size-exclusion chromatography

Chemical Modification of Glycosaminoglycan Polysaccharides

The linear anionic class of polysaccharides, glycosaminoglycans (GAGs), are critical throughout the animal kingdom for developmental processes and the maintenance of healthy tissues. They are also of interest as a means of influencing biochemical processes. One member of the GAG family, heparin, is exploited globally as a major anticoagulant pharmaceutical and there is a growing interest in the potential of other GAGs for diverse applications ranging from skin care to the treatment of neurodegenerative conditions, and from the treatment and prevention of microbial infection to biotechnology. To realize the potential of GAGs, however, it is necessary to develop effective tools that are able to exploit the chemical manipulations to which GAGs are susceptible. Here, the current knowledge concerning the chemical modification of GAGs, one of the principal approaches for the study of the structure-function relationships in these molecules, is reviewed. Some additional methods that were applied successfully to the analysis and/or processing of other carbohydrates, but which could be suitable in GAG chemistry, are also discussed.

Detection challenges in quantitative polymer analysis by liquid chromatography

Accurate quantification of polymer distributions is one of the main challenges in polymer analysis by liquid chromatography. The response of contemporary detectors is typically influenced by compositional features such as molecular weight, chain composition, end groups, and branching. This renders the accurate quantification of complex polymers of which there are no standards available, extremely challenging. Moreover, any (programmed) change in mobile-phase composition may further limit the applicability of detection techniques. Current methods often rely on refractive index detection, which is not accurate when dealing with complex samples as the refractive-index increment is often unknown. We review current and emerging detection methods in liquid chromatography with the aim of identifying detectors, which can be applied to the quantitative analysis of complex polymers.

Isolation and structural characterization of sulfated polysaccharide from Spirulina platensis and its bioactive potential: In vitro antioxidant, antibacterial activity and Zebrafish growth and reproductive performance

In this study, the sulfated polysaccharide (SPs) was isolated from Spirulina platensis. The isolated SPs contains carbohydrate, sulfate, protein and uronic acid at 38.7 ± 0.30%, 21.3 ± 0.87%, 7.1 ± 0.15% and 7.9 ± 0.4% respectively. The elemental analysis confirmed the presence of carbon (18.01 ± 0.10%), hydrogen (1.83 ± 0.02%) and nitrogen (3.43 ± 0.01%). The monosaccharide composition and molecular weight of SPs were analyzed by high-performance liquid chromatography and size exclusion chromatography respectively. The monosaccharide composition analysis showed the existence of glucose, rhamnose, xylose, fucose, mannose, galactose and the molecular weight of SPs was 1016 kDa. Further, the characterization of SPs was done by UV-visible spectroscopy, X-ray diffraction, FT-IR, ¹H NMR and ¹³C NMR analysis. The obtained SPs exhibited potent antioxidant activity in DPPH (76.45 ± 0.49%), reducing power (absorbance: 1.3 ± 0.02), hydrogen peroxide scavenging (66.3 ± 1.16%), hydroxyl scavenging (68.6 ± 3.2%), nitric oxide (81.36 ± 1.85%) and total antioxidant (absorbance:1.66 ± 0.02) activities at 5 mg/ml. In addition, SPs revealed the highest antibacterial efficacy against the pathogenic bacteria Vibrio vulnificus in disc diffusion, agar bioassay and protein leakage assays at 100 μg/ml. Furthermore, the supplementation of 2% SPs through a feed to the Danio rerio fish enhances the growth and reproductive performances. This finding confirmed that the isolated SPs from S. platensis possess pharmaceutical as well as nutritional properties.

Photochemical Preparation of a Novel Low Molecular Weight Heparin

Commercial low molecular weight heparins (LMWHs) are prepared by several methods including peroxidative cleavage, nitrous acid cleavage, chemical ß-elimination, and enzymatic β-elimination. The disadvantages of these methods are that strong reaction conditions or harsh chemicals are used and these can result in decomposition or modification of saccharide units within the polysaccharide backbone. These side-reactions reduce product quality and yield. Here we show the partial photolysis of unfractionated heparin can be performed in distillated water using titanium dioxide (TiO(2)). TiO(2) is a catalyst that can be easily removed by centrifugation or filtration after the photochemical reaction takes place, resulting in highly pure products. The anticoagulant activity of photodegraded LMWH (pLMWH) is comparable to the most common commercially available LMWHs (i.e., Enoxaparin and Dalteparin). (1)H NMR spectra obtained show that pLMWH maintains the same core structure as unfractionated heparin. This photochemical reaction was investigated using liquid chromatography/mass spectrometry (LC/MS) and unlike other processes commonly used to prepare LMWHs, photochemically preparation affords polysaccharide chains of reduced length having both odd and even of saccharide residues.

Hyaluronan: pharmaceutical characterization and drug delivery

Hyaluronic acid (HA), is a polyanionic polysaccharide that consists of N-acetyl-D-glucosamine and beta-glucoronic acid. It is most frequently referred to as hyaluronan because it exists in vivo as a polyanion and not in the protonated acid form. HA is distributed widely in vertebrates and presents as a component of the cell coat of many strains of bacteria. Initially the main functions of HA were believed to be mechanical as it has a protective, structure stabilizing and shock-absorbing role in the body. However, more recently the role of HA in the mediation of physiological functions via interaction with binding proteins and cell surface receptors including morphogenesis, regeneration, wound healing, and tumor invasion, as well as in the dynamic regulation of such interactions on cell signaling and behavior has been documented. The unique viscoelastic nature of hyaluronan along with its biocompatibility and nonimmunogenicity has led to its use in a number of cosmetic, medical, and pharmaceutical applications. More recently, HA has been investigated as a drug delivery agent for ophthalmic, nasal, pulmonary, parenteral, and dermal routes. The purpose of our review is to describe the physical, chemical, and biological properties of native HA together with how it can be produced and assayed along with a detailed analysis of its medical and pharmaceutical applications.

Modulation of blood coagulation and fibrinolysis by polyamines in the presence of glycosaminoglycans

The effects of polyamines on blood coagulation and fibrinolysis in the presence of glycosaminoglycans (GAGs) were examined because it is known that heparin (HP) interacts with polyamines, especially with spermine. Spermine was able to reverse the prolongation of coagulation time of rabbit plasma caused by HP. The effects of various GAGs on thrombin activity in the presence of anti-thrombin III (AT) were then tested using a synthetic substrate. Inhibition of thrombin activity by GAGs was in the order HP > heparan sulfate (HS) > dermatan sulfate (DS) >> chondroitin sulfate (CS) approximately hyaluronan (HA). When these GAGs were fully sulfonated, the inhibitory activity of HS, DS, CS and HA, but not HP, became stronger. The effects of GAGs on thrombin activity were reversed by polyamines, in particular spermine. The EC(50) value of spermine for reversal of HP inhibition was 30-50 microM, and the K(d) value of spermine for heparin was 41.1 microM. Analysis by surface plasmon resonance (SPR) indicated that the interaction between AT and HP was weakened by spermine through its binding to HP. The effect of HP on fibrinolysis was then examined. When Glu-plasminogen and tissue-type plasminogen activator (tPA) were used as enzyme source, HP strongly enhanced the plasmin activity and spermine reversed this effect. Analysis by SPR suggests that the structure of the active site of tPA may be changed through the ternary complex formation of tPA, HP and spermine. The results indicate that blood coagulation was enhanced and fibrinolysis was weakened by spermine in the presence of HP.

Pep-1 as a novel probe for the in situ detection of hyaluronan

Hyaluronan (HA) is expressed by most tissues, including skin. Localization of HA in the skin is assessed by histology with HA-binding protein (HABP) serving as the probe. Reports have suggested that HA expression in skin is altered in a number of diseases. However, interlaboratory variations in HABP staining profiles, even in normal skin, suggest a need to standardize methods and/or identify new probes. We report the staining patterns of a HA-binding peptide (termed "Pep-1") in human and mouse skin. After acetone fixation, Pep-1 stained HA in the intercellular spaces of the epidermis, whereas staining in the dermis was weak and diffuse in both human and mouse skin. HABP staining of the epidermis and dermis were comparable in human skin but failed to stain the vital epidermis of mouse skin. In human skin, Pep-1 stained the basal, spinous, and granular layers, whereas HABP failed to stain the basal layer. Precipitation of HA in situ resulted in dermal staining but weak staining in the epidermis for HABP and Pep-1. Our results may suggest that Pep-1 is sensitive to HA conformation. Furthermore, Pep-1 may represent a new probe to study HA expression in the skin.

Hyaluronic acid: separation and biological implications

Hyaluronic acid (hyaluronan) is a ubiquitous extracellular matrix component, and present at high concentrations in skin, joints and cornea. In the skin, it is synthesized primarily by dermal fibroblasts and by epidermal keratinocytes. Hyaluronic acid usually exists as a high molecular mass (600,000-1,000,000) and non-sulfated glycosaminoglycan composed of a disaccharide unit of [bond]3GlcNAc beta 1[bond]4GlcA beta 1[bond]. Hyaluronic acid has been widely used not only for osteoarthritis and ophthalmology but also for cosmetics for skin care. To examine the biological activities of hyaluronic acid, we have to accurately determine the quantity and molecular masses in biological samples. We review recent development in the analysis of hyaluronic acid having various molecular sizes using electrophoretic and chromatographic techniques. Recently, interactions between hyaluronic acid oligomers and hyaluronic acid-binding proteins have attracted the interest for understanding the biological functions. We show some interesting reports on biological interactions of hyaluronic acid and its oligomers with some proteins.

Purification and characterization of dermatan sulfate from the skin of the eel, Anguilla japonica

Glycosaminoglycans were isolated from the eel skin (Anguilla japonica) by actinase and endonuclease digestions, followed by a beta-elimination reaction and DEAE-Sephacel chromatography. Dermatan sulfate was the major glycosaminoglycan in the eel skin with 88% of the total uronic acid. The content of the IdoA2Salpha1-->4GalNAc4S sequence in eel skin, which shows anticoagulant activity through binding to heparin cofactor II, was two times higher than that of dermatan sulfate from porcine skin. The anti-IIa activity of eel skin dermatan sulfate was determined to be 2.4 units/mg, whereas dermatan sulfate from porcine skin shows 23.2 units/mg. The average molecular weight of dermatan sulfate was determined by gel chromatography on a TSKgel G3000SWXL column as 14 kDa. Based on 1H NMR spectroscopy, the presence of 3-sulfated and/or 2,3-sulfated IdoA residues was suggested. The reason why highly sulfated dermatan sulfate does not show anticoagulant activity is discussed. In addition to dermatan sulfate, the eel skin contained a small amount of keratan sulfate, which was identified by keratanase treatment.