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 (center dot OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O (2) (-) scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the center dot OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.

Sulfato de glucosamina e de condroitina sobre o desempenho, cartilagem articular e densidade mineral óssea em frangos de corte

Pós-graduação em Zootecnia - FCAV

Efeitos da oxigenoterapia hiperbárica e do sulfato de condroitina-A associado ao sulfato de glucosamina na reparação óssea de coelhos

Objetivo: Estudar o hemograma e avaliar radiológica e morfológicamente a reparação do calo ósseo após a lesão na diáfise femural de coelhos. Métodos: foram utilizados 48 coelhos independentes do sexo, Nova Zelândia, onde estes foram anestesiados e submetidos à ostectomia do côndilo femoral medial direito e osteossíntese, randomizados e distribuídos em 4 grupos (n = 12 em cada): Grupo Controle (I), Grupo Sulfato de Condroitina-A associado ao Sulfato de Glucosamina (II), sendo que a aplicação de Sulfato de Condroitina-A associado ao Sulfato de Glucosamina (2mL.10Kg -1 ) iniciou no pós-operatório imediato seguido de aplicações a cada 3 dias; Grupo Oxigenoterapia Hiperbárica (III): com sessões diárias (3 ATA durante 130 minutos, sendo 90 minutos de pressão absoluta) iniciadas no primeiro dia de pós-operatório; Grupo Sulfato de Condroitina-A associado ao Sulfato de Glucosamina e Oxigenoterapia Hiperbárica (IV). Os animais foram eutanasiados após 2 (n=6 de cada grupo) e 6 semanas (n=6 de cada grupo) de pós-operatório. Resultados: Diferenças significantes foram encontradas entre os grupos de 2 e 6 semanas de pós-operatório, quanto à média do comprimento do calo ósseo nos grupos: I (p = 0,001), II (p = 0,012) e IV (p = 0,001). A comparação entre os quatro grupos após 2 semanas mostrou diferença significante (p < 0,001), onde o grupo I apresentou média de comprimento caloso menor que os grupos II (p = 0,001), III (p = 0,001) e IV (p = 0,008), de maneira significante. Os demais grupos não se diferenciaram de forma significante (p > 0,05) nas demais comparações. Entretanto, após 6 semanas a comparação entre os quatro grupos mostrou diferença significante onde: o grupo I apresentou média de comprimento menor que os grupos III (p = 0,006) e IV (p < 0,001); o grupo II apresentou média de comprimento menor que os grupos III (p = 0,001) e IV (p < 0,001). Os demais grupos não se diferenciaram de forma significante (p > 0,05) nas demais comparações. Nos achados radiológicos de até duas semanas encontramos uma formação calosa rápida nos grupos que receberam oxigenoterapia hiperbárica (83% dos animais do grupo III) isoladamente ou em associação com o sulfato de condroitina-a associado ao sulfato de glucosamina (33% dos animais do grupo IV) quando comparados ao grupo controle. Já com seis semanas esta diferença diminui, mas ainda o grupo III (83%) apresenta um maior número de animais com formação calosa do que no grupo IV (67%). Sendo que os resultados radiológicos mostram a possibilidade de uma melhor ação da oxigenoterapia hiperbárica (83% dos animais) de forma isolada, pois quando comparada com o grupo II isolado (67% dos animais) ainda sugere uma superioridade na formação calosa mais rápida ao término do período precoce. Não foram encontradas alterações nos parâmetros hematológicos com as intervenções utilizadas. Conclusões: A oxigenoterapia hiperbárica e o sulfato de condroitina-a associado ao sulfato de glucosamina, isoladas ou em associação promovem aumento do calo ósseo e não promovem alterações nos parâmetros hematológicos dos animais nos tempos estudados.

Health characteristics of older Australian dietary supplement users compared to non-supplement users

The aim of this study was to measure the prevalence of dietary and health supplement use among Australians aged 65 years and over, and to contrast the health differences between supplement users and non-supplement users. Data was obtained from 1,263 randomly selected older Australians, who provided general demographic data, in addition to information related to their health, symptoms experienced and uses of medication, including dietary supplements. Supplement use was reported by 43% of the sample (52% of females and 35% of males). This investigation has revealed distinct differences in the health profile of older supplement users compared to non-users. Although there was no difference in the number of visits to medical doctors or self-rated health status between supplement users and non-supplement users, supplement users were more likely to report arthritis and osteoporosis, and experience more symptoms and consume more medication than non-supplement users. In contrast, there was a reduced likelihood of taking a supplement for those with hypertension and by those using blood pressure medication and heart tablets. These results suggest that older dietary supplement users may benefit from education and professional advice to assist them make appropriate and informed choices, particularly if they expect these preparations to attenuate their health concerns.

Arthritic disease suppression and cartilage protection with glycosaminoglycan polypeptide complexes (Peptacans) derived from the cartilage extracellular matrix: A novel approach to therapy

Molecular fragments of cartilage are antigenic and can stimulate an autoimmune response. Oral administration of type II collagen prevents disease onset in animal models of arthritis but the effects of other matrix components have not been reported. We evaluated glycosaminoglycan polypeptides (GAG-P) and matrix proteins (CaP) from cartilage for a) mitigating disease activity in rats with collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) and b) stimulating proteoglycan (PG) synthesis by chondrocytes in-vitro. CIA and AIA were established in Wistar rats using standard methods. Agents were administered orally (10–200 mg/kg), either for seven days prior to disease induction (toleragenic protocol), or continuously for 15 days after injecting the arthritigen (prophylactic protocol). Joint swelling and arthritis scores were determined on day 15. Histological sections of joint tissues were assessed post-necropsy. In chondrocyte cultures, CaP + / − interleukin-1 stimulated PG biosynthesis. CaP was also active in preventing arthritis onset at 3.3, 10 or 20 mg/kg in the rat CIA model using the toleragenic protocol. It was only active at 20 and 200 mg/kg in the CIA prophylactic protocol. GAG-P was active in the CIA toleragenic protocol at 20 mg/kg but chondroitin sulfate and glucosamine hydrochloride or glucosamine sulfate were all inactive. The efficacy of CaP in the rat AIA model was less than in the CIA model. These findings lead us to suggest that oral CaP could be used as a disease-modifying anti-arthritic drug.

Urinary glycosaminoglycans in horse osteoarthritis. Effects of chondroitin sulfate and glucosamine

Our objectives were to characterize the urinary excretion of glycosaminoglycans (GAGs) in horse osteoarthritis, and to investigate the effects of chondroitin sulfate (CS) and glucosamine (GlcN) upon the disease. Urinary GAGs were measured in 47 athletic horses, 20 healthy and 27 with osteoarthritis. The effects of CS and GlcN were investigated in mild osteoarthritis. In comparison to normal, urinary GAGs were increased in osteoarthritis, including mild osteoarthritis affecting only one joint. Treatment with CS + GlcN led to a long lasting increase in the urinary CS and keratan sulfate (KS), and significant improvement in flexion test of tarsocrural and metacarpophalangeal joints was observed. In conclusion, urinary CS and KS seems to reflect the turnover rates of cartilage matrix proteoglycans, and the measurement of these compounds could provide objective means of evaluating and monitoring joint diseases. (C) 2011 Elsevier Ltd. All rights reserved.

Drug-induced acute liver injury mimicking autoimmune hepatitis after intake of dietary supplements containing glucosamine and chondroitin sulfate

INTRODUCTION Herbal and dietary supplements are widely used as measures to improve and preserve health and well-being. Among the bestselling preparations are dietary supplement containing glucosamine and chondroitine sulfate taken to improve symptoms of osteoarthritis. METHODS AND RESULTS We here present a case of a male patient with biopsy-proven acute and severe autoimmune hepatitis subsequent to intake of a preparation containing glucosamine and chondroitine sulfate. Response to steroids was favorable and resulted in complete remission of the patient. Diagnostic work-up of the case revealed no other possible cause of liver injury, and causality assessment using the Roussel Uclaf Causality Assessment Method (RUCAM) resulted in a possible causal relationship between intake of glucosamine and chondroitine sulfate and the adverse hepatic reaction. CONCLUSION The present case recalls that products containing glucosamine and chondroitine sulfate can occasionally cause acute liver injury mimicking autoimmune hepatitis, and reminds of the potential dangers of compounds with poor efficacy and ill-defined safety records.

Sequencing of 3-O sulfate containing heparin decasaccharides with a partial antithrombin III binding site

Heparin- and heparan sulfate-like glycosaminoglycans (HLGAGs) represent an important class of molecules that interact with and modulate the activity of growth factors, enzymes, and morphogens. Of the many biological functions for this class of molecules, one of its most important functions is its interaction with antithrombin III (AT-III). AT-III binding to a specific heparin pentasaccharide sequence, containing an unusual 3-O sulfate on a N-sulfated, 6-O sulfated glucosamine, increases 1,000-fold AT-III's ability to inhibit specific proteases in the coagulation cascade. In this manner, HLGAGs play an important biological and pharmacological role in the modulation of blood clotting. Recently, a sequencing methodology was developed to further structure-function relationships of this important class of molecules. This methodology combines a property-encoded nomenclature scheme to handle the large information content (properties) of HLGAGs, with matrix-assisted laser desorption ionization MS and enzymatic and chemical degradation as experimental constraints to rapidly sequence picomole quantities of HLGAG oligosaccharides. Using the above property-encoded nomenclature-matrix-assisted laser desorption ionization approach, we found that the sequence of the decasaccharide used in this study is ΔU2SHNS,6SI2SHNS,6SI2SHNS,6SIHNAc,6SGHNS,3S,6S (±DDD4–7). We confirmed our results by using integral glycan sequencing and one-dimensional proton NMR. Furthermore, we show that this approach is flexible and is able to derive sequence information on an oligosaccharide mixture. Thus, this methodology will make possible both the analysis of other unusual sequences in HLGAGs with important biological activity as well as provide the basis for the structural analysis of these pharamacologically important group of heparin/heparan sulfates.

Near-infrared spectroscopic study of basic aluminum sulfate and nitrate

The tridecameric Al-polymer [AlO4Al12(OH)24(H2O)12]7+ was prepared by forced hydrolysis of Al3+ up to an OH/Al molar ratio of 2.2. Under slow evaporation crystals were formed of Al13-nitrate. Upon addition of sulfate the tridecamer crystallised as the monoclinic Al13-sulfate. These crystals have been studied using near-infrared spectroscopy and compared to Al2(SO4)3.16H2O. Although the near-infrared spectra of the Al13-sulfate and nitrate are very similar indicating similar crystal structures, there are minor differences related to the strength with which the crystal water molecules are bonded to the salt groups. The interaction between crystal water and nitrate is stronger than with the sulfate as reflected by the shift of the crystal water band positions from 6213, 4874 and 4553 cm–1 for the Al13 sulfate towards 5925, 4848 and 4532 cm–1 for the nitrate. A reversed shift from 5079 and 5037 cm–1 for the sulfate towards 5238 and 5040 cm–1 for the nitrate for the water molecules in the Al13 indicate that the nitrate-Al13 bond is weakened due to the influence of the crystal water on the nitrate. The Al-OH bond in the Al13 complex is not influenced by changing the salt group due to the shielding by the water molecules of the Al13 complex.

Synthesis of a heparan sulfate mimetic disaccharide with a conformationally locked residue from a common intermediate

A simple mimetic of a heparan sulfate disaccharide sequence that binds to the growth factors FGF-1 and FGF-2 was synthesized by coupling a 2-azido-2-deoxy-D-glucosyl trichloroacetimidate donor with a 1,6-anhydro-2-azido-2-deoxy--D-glucose acceptor. Both the donor and acceptor were obtained from a common intermediate readily obtained from D-glucal. Molecular docking calculations showed that the predicted locations of the disaccharide sulfo groups in the binding site of FGF-1 and FGF-2 are similar to the positions observed for co-crystallized heparin-derived oligosaccharides obtained from published crystal structures.

The PG500 series : novel heparan sulfate mimetics as potent angiogenesis and heparanase inhibitors for cancer therapy

Heparan sulfate mimetics, which we have called the PG500 series, have been developed to target the inhibition of both angiogenesis and heparanase activity. This series extends the technology underpinning PI-88, a mixture of highly sulfated oligosaccharides which reached Phase III clinical development for hepatocellular carcinoma. Advances in the chemistry of the PG500 series provide numerous advantages over PI-88. These new compounds are fully sulfated, single entity oligosaccharides attached to a lipophilic moiety, which have been optimized for drug development. The rational design of these compounds has led to vast improvements in potency compared to PI-88, based on in vitro angiogenesis assays and in vivo tumor models. Based on these and other data, PG545 has been selected as the lead clinical candidate for oncology and is currently undergoing formal preclinical development as a novel treatment for advanced cancer.

A surface plasmon resonance-based solution affinity assay for heparan sulfate-binding proteins

A surface plasmon resonance-based solution affinity assay is described for measuring the Kd of binding of heparin/heparan sulfate-binding proteins with a variety of ligands. The assay involves the passage of a pre-equilibrated solution of protein and ligand over a sensor chip onto which heparin has been immobilised. Heparin sensor chips prepared by four different methods, including biotin–streptavidin affinity capture and direct covalent attachment to the chip surface, were successfully used in the assay and gave similar Kd values. The assay is applicable to a wide variety of heparin/HS-binding proteins of diverse structure and function (e.g., FGF-1, FGF-2, VEGF, IL-8, MCP-2, ATIII, PF4) and to ligands of varying molecular weight and degree of sulfation (e.g., heparin, PI-88, sucrose octasulfate, naphthalene trisulfonate) and is thus well suited for the rapid screening of ligands in drug discovery applications.

Heparan sulfate mediates the proliferation and differentiation of rat mesenchymal stem cells

The growth and differentiation of mesenchymal stem cells is controlled by various growth factors, the activities of which can be modulated by heparan sulfates. We have previously underscored the necessity of sulfated glycosaminoglycans for the FGF-2-stimulated differentiation of osteoprogenitor cells. Here we show that exogenous application of heparan sulfate to cultures of primary rat MSCs stimulates their proliferation leading to increased expression of osteogenic markers and enhanced bone nodule formation. FGF-2 can also increase the proliferation and osteogenic differentiation of rMSCs when applied exogenously during their linear growth. However, as opposed to exogenous HS, the continuous use of FGF-2 during in vitro differentiation completely blocked rMSC mineralization. Furthermore, we show that the effects of both FGF-2 and HS are mediated through FGF receptor 1 (FGFR1) and that inhibition of signaling through this receptor arrests cell growth resulting in the cells being unable to reach the critical density necessary to induce differentiation. Interestingly, blocking FGFR1 signaling in post-confluent osteogenic cultures significantly increased calcium deposition. Taken together our data clearly suggests that FGFR1 signaling plays an important role during osteogenic differentiation, firstly by stimulating cell growth that is closely followed by an inhibitory affect once the cells have reached confluence. It also underlines the importance of HS as a co-receptor for the signaling of endogenous FGF-2 and suggests that purified glycosaminoglycans may be attractive alternatives to growth factors for improved ex vivo growth and differentiation of MSCs.

Sustained release and osteogenic potential of heparan sulfate-doped fibrin glue scaffolds within a rat cranial model

This paper explores the potential therapeutic role of the naturally occurring sugar heparan sulfate (HS) for the augmentation of bone repair. Scaffolds comprising fibrin glue loaded with 5 lg of embryonically derived HS were assessed, firstly as a release-reservoir, and secondly as a scaffold to stimulate bone regeneration in a critical size rat cranial defect. We show HS-loaded scaffolds have a uniform distribution of HS, which was readily released with a typical burst phase, quickly followed by a prolonged delivery lasting several days. Importantly, the released HS contributed to improved wound healing over a 3-month period as determined by microcomputed tomography (lCT) scanning, histology, histomorphometry, and PCR for osteogenic markers. In all cases, only minimal healing was observed after 1 and 3 months in the absence of HS. In contrast, marked healing was observed by 3 months following HS treatment, with nearly full closure of the defect site. PCR analysis showed significant increases in the gene expression of the osteogenic markers Runx2, alkaline phosphatase, and osteopontin in the heparin sulfate group compared with controls. These results further emphasize the important role HS plays in augmenting wound healing, and its successful delivery in a hydrogel provides a novel alternative to autologous bone graft and growth factorbased therapies.