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PubMed1987

Replication of porcine circovirus: induction by glucosamine and cell cycle dependence.

Multiplication of porcine circovirus (PCV) was found to be inducible by treatment of infected cell cultures with 300 mM glucosamine. One day after glucosamine treatment and after growth in fresh medium, an increase in the number of cells containing virus antigen of up to 50 times as compared to mock-treated cultures was observed. Analysis of this phenomenon revealed that replication of PCV DNA was induced. Only aminohexoses but not hexoses and acetylated aminohexoses were efficacious. The course of PCV replication in synchronized cell cultures infected at different periods of the cell cycle showed that PCV DNA synthesis depends on cellular enzymes expressed during S phase growth of cells. However, whereas in cell cultures treated with glucosamine after infection in G0 or during G1, the start of PCV replication was observed during the first S phase after growth stimulation, the latent period in mock-treated cultures lasted until the second S phase. Also in cell cultures transfected with PCV DNA in G0 or during G1 using DEAE-dextran as mediator, PCV replication started during the first S phase after growth release of the cells. From these findings the conclusion is drawn that glucosamine and DEAE-dextran initiate PCV replication by enabling the PCV genome to get entry to the cell nucleus that normally can be achieved only by inclusion in the daughter nuclei at the end of mitosis.

Adsorption↗

PubMed1983

An improved gas chromatographic method for measuring glucosamine and muramic acid concentrations.

A method of simultaneously measuring glucosamine and muramic acid concentrations in marsh grass litter was developed. Spartina alterniflora samples were preextracted with acetone to remove lipids containing amino sugars and then hydrolyzed in 6 N HCl (100 degrees C, 4.5 h). Amino sugars in the hydrolysates were isolated by ion-exchange chromatography, which gave good recoveries (greater than 90%) and reproducibility (CV less than 5%). Isolated amino sugars were converted to O-methyloxime acetates. beta-Phenylglucose and N-methylglucamine were added as internal standards. Sample derivatives were quantified by capillary column gas chromatography. OV-101 and SE-54 capillary columns completely separated glucosamine and muramic acid from other amino sugars. The detection limit of glucosamine and muramic acid during gas chromatographic analysis was below 30 pmol using splitless-mode injection (SE-54 column). Filamentous fungal and procaryotic biomasses may be estimated simultaneously by using glucosamine and muramic acid biomass conversion factors in conjunction with this method.

Animals↗

PubMed1990

Quantitative analysis of N-sulfated, N-acetylated, and unsubstituted glucosamine amino groups in heparin and related polysaccharides.

A colorimetric procedure for quantitative determination of free and substituted glucosamine amino groups in heparin and related polysaccharides has been developed. The total content of hexosamine amino groups is determined by a modification of the method of Tsuji et al. (1969, Chem. Pharm. Bull. 17, 1505-1510); this method involves acid hydrolysis under conditions effecting complete removal of N-acetyl and N-sulfate groups, deaminative cleavage with nitrous acid, and colorimetric analysis of the resultant anhydromannose residues by reaction with 3-methyl-2-benzothiazolinone hydrazone (MBTH). N-sulfated glucosamine residues are cleaved selectively by treatment with nitrous acid at pH approximately 1.5 (J. E. Shively, and H.E. Conrad, 1976, Biochemistry 15, 3932-3942) and quantitated by the MBTH reaction. Under carefully controlled conditions, deamination at pH approximately 1.5 is highly specific for N-sulfated glucosamine residues, but an excess of reagent causes some cleavage of residues with unsubstituted amino groups as well. Deaminative cleavage at pH approximately 4.5 results in preferential degradation of unsubstituted glucosamine residues, but some cleavage (5-8%) of N-sulfated residues also occurs. However, analysis of the content of N-sulfated residues by the specific pH 1.5 procedure allows appropriate corrections to be made. From the value for total hexosamine content and the sum of N-sulfated and unsubstituted residues, the content of N-acetylated residues is calculated by difference. The modified deamination procedures, in combination with product analysis by the MBTH reaction, have been applied to several problems commonly encountered in the analysis and characterization of heparin.

Acetylglucosamine↗

PubMed1984

Equilibration of [3H]glucosamine and [35S]sulfate with intracellular pools of UDP-N-acetylhexosamine and 3'-phosphoadenosine-5'-phosphosulfate (PAPS) in cultured fibroblasts.

Nucleotides and sugar nucleotides were extracted from cultures of human fibroblasts with perchloric acid, separated by isotachophoresis, and quantified by uv absorption analysis at 254 nm. ATP (936 pmol/micrograms DNA) was, as expected, the dominating nucleotide pool. The energy charge was estimated to 0.9. The UDP-N-acetylhexosamine pool was also a very prominent compound (596 pmol/micrograms DNA). After incubation of fibroblasts with [3H]glucosamine, more than 95% of the acid-soluble radioactivity was found in the UDP-N-acetylhexosamine pool. Incubation with [35S]sulfate resulted in the incorporation of [35S]sulfate into 3'-phosphoadenosine-5'-phosphosulfate (PAPS). The latter could, however, only be measured as radioactivity, as the amount was too small to be quantified as total mass. Pulse-labeling of fibroblasts with [35S]sulfate and [3H]glucosamine from 5 min to 16 h showed that [35S]PAPS was equilibrated in less than 10 min, while [3H]glucosamine required a longer time, 2-4 h, to attain a steady state with UDP-N-acetylhexosamine. [14C]Glucose required approximately the same time as [3H]glucosamine to reach steady state with UDP-acetylhexosamine, which suggests that the reason for the long equilibration time is the slow turnover of this pool.

Adenine Nucleotides↗

PubMed1983

Comparison in vitro of the incorporation of D-[2-3H(N)]-mannose and D-[1-14C]-glucosamine into glycoproteins of dispersed rat submandibular salivary gland cells.

The incorporation of two different radiolabelled sugars, D-[14C]-glucosamine and D-[2-3H(N)]-mannose, into cellular and secretory glycoproteins was compared using dispersed rat submandibular cells. Most of the de-novo biosynthesis appeared to be directed toward the synthesis of secretory material as the molecular profile of the 3H-labelled material released following sympathomimetic stimulation and the percentage of total 3H-labelled acid--precipitable material secreted following cholinergic- or adrenergic-receptor stimulation coincided with the data obtained from similar studies using [14C]-glucosamine. The [3H]-mannose label was found in the neutral sugars mannose, galactose, glucose and fucose, with trace amounts of radiolabel in the amino sugars, whereas the [14C]-glucosamine label was present in three different amino sugars; glucosamine, galactosamine and sialic acid.

Animals↗

PubMed1989

Inhibition by glucosamine of myristoylation in human H9 lymphocytes and rat liver cells.

N-Myristoyl transferase (NMT) activity was measured in rat liver and H9 cells using an in vitro assay based on acylation of synthetic peptides. Glucosamine was found to inhibit the NMT activity. Using a synthetic peptide mimicking the N-terminus of HIV p27nef a Km value of 2.4 microM and a Vmax of 240 pmol/mg per h was found. In the presence of glucosamine the Vmax was lowered indicating that glucosamine acted as a non-competitive inhibitor. Glucosamine also inhibited incorporation of radiolabelled myristic acid into H9 cell proteins in vivo. In liver cells using a peptide from the N-terminus of p60 SRC only the Vmax was affected.

Acylation↗

PubMed1983

Effect of D-glucosamine on the content and synthesis of UDP-sugars and plasma membrane associated carbohydrates in chicken liver and hepatoma Mc-29.

1. Comparative studies on the effect of D-glucosamine on the synthesis of UDP-sugars and on the incorporation rate of [14C]glucose into neutral sugars, sialic acid and glucosamine isolated from chicken liver and hepatoma Mc-29 plasma membranes have been carried out. 2. The influence of D-glucosamine on the activity of microsomal UDP-N-acetylglucosamine: glycoprotein N-acetylglucosaminyltransferase to lipid (dolichol monophosphate) and to protein acceptor was studied too. 3. It has been shown that D-glucosamine provokes alterations in the content and synthesis of UDP-sugars and it is an inhibitor of the glycosylation processes. An inhibitory effect of this sugar analog on the N-acetylglycosaminyltransferase has been established.

Animals↗

PubMed1986

Uridine enhances the cytotoxic effect of D-glucosamine in rat C6 glioma cells.

This paper studies the influence of uridine on the effects exerted by D-glucosamine in rat C6 glioma cells. 2 mM uridine increased markedly both the cytotoxic effect of the aminosugar and the inhibition of thymidine incorporation into acid-insoluble fraction. Furthermore the complete resumption of the capacity to incorporate either 3H-thymidine or 3H-mannose which was observed after the removal of the aminosugar, was impeded when the cells were treated contemporaneously with D-glucosamine and uridine. An exposure for 4 hr to 20 mM glucosamine alone enhanced about 15-fold the cellular pool of UDP-N-acetylhexosamines; the addition of 2 mM uridine intensified the expansion of this pool, which became about 35-fold the control value. The findings suggest a connection between the accumulation of UDP-N-acetylhexosamines in the cells and the appearance of D-glucosamine cytotoxicity.

Animals↗

PubMed1980

3H-glucosamine and 3H-fucose incorporation by murine peritoneal macrophages "non-divided" during differentiation in vitro.

Normal murine peritoneal macrophages were maintained in culture for 24 hours and 6 days. These cells continuously incorporated 3H-glucosamine and 3H-fucose in their membrane components. For both precursors culture ages, these components may be considered to undergo turnover according to a given rhythm with a 24 hours doubling time. Treatment with neuraminidase did not modify the doubling time, although a slight increase of incorporation of radioactivity was observed. Variations of 3H-fucose and 3H-glucosamine incorporations were observed. Variations of 3H-fucose and 3H-glucosamine incorporations were observed between 24 hours old and 6 days old cultures: 6 days old cultures incorporated more glucosamine than 24 hours old cultures whereas no difference in fucose incorporation was observed between the two cultures.

Animals↗

PubMed2004

Effectiveness of glucosamine for symptoms of knee osteoarthritis: results from an internet-based randomized double-blind controlled trial.

PURPOSE: To present the safety and effectiveness results of a prototypical 12-week, double-blind, randomized placebo-controlled trial of glucosamine among subjects with knee osteoarthritis who were recruited and followed entirely over the Internet. METHODS: The study comprised 205 subjects aged 45 years or older with symptomatic knee osteoarthritis who were recruited over the Internet; eligibility was authenticated through medical record review. Participants were assigned randomly to 1.5 g/d of glucosamine (n = 101) or placebo (n = 104), of whom 108 completed the intervention (93 in each arm). The primary outcome measure was the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (Likert version). Additional outcome measures included the physical function and stiffness subscales and overall score of the questionnaire, and analgesic use. RESULTS: There was no difference between treatment and control groups in terms of change in pain score (2.0 +/- 3.4 vs. 2.5 +/- 3.8, P = 0.41), stiffness (0.7 +/- 1.6 vs. 0.8 +/- 1.5, P = 0.52), physical function (5.2 +/- 9.5 vs. 4.6 +/- 9.6, P = 0.49), overall score (7.8 +/- 13.1 vs. 7.8 +/- 13.5, P = 0.81), and analgesic use (133 +/- 553 vs. -88 +/- 755, P = 0.12). Stratification by osteoarthritis severity, glucosamine product, and use of a nonsteroidal anti-inflammatory drug, as well as exclusion of opiate users, did not alter the results. The number and type of adverse events reported was similar between the groups. CONCLUSION: Our results suggest that although glucosamine appears to be safe, it is no more effective than placebo in treating the symptoms of knee osteoarthritis.

Aged↗

PubMed2006

Validation of a high-performance thin-layer chromatography/densitometry method for the quantitative determination of glucosamine in a herbal dietary supplement.

A quantitative densitometric high-performance thin-layer chromatography (HPTLC) method was developed for the determination of glucosamine in a dietary supplement containing dried extracts of the main plants traditionally used for rheumatic disorders. The HPTLC method was chosen in order to circumvent the tedious and time-consuming sample preparation steps necessarily performed before using HPLC methods when analysing complex matrixes. Glucosamine was separated from the plant extracts on a silica gel 60 F(254) HPTLC plate using a saturated mixture of 2-propanol-ethyl acetate-ammonia solution (8%) (10:10:10, v/v/v). The plates were developed vertically up to a distance of 80 mm. For visualization, the plate was dipped into a modified anisaldehyde reagent and heated at 120 degrees C for 30 min in a drying oven. Glucosamine appeared as brownish-red chromatographic zones on a colourless background. Densitometric quantification was performed at lambda = 415 nm by reflectance scanning. The HPTLC method was successfully validated by applying the novel validation protocol proposed by a commission of the "Société Française des Sciences et Techniques Pharmaceutiques" (SFSTP). In the pre-validation phase, the appropriate response function was determined, while in the validation phase the method showed good performance thereby fulfilling its objective of quantifying accurately. The relative standard deviations for repeatability and intermediate precision were between 4.9 and 8.6%. Moreover, the method was found to be accurate, as the two-sided 95% beta-expectation tolerance interval did not exceed the acceptance limits of 85 and 115% on the whole analytical range (800-1,200 ng of glucosamine).

Chromatography, High Pressure Liquid↗

PubMed2006

Determination of glucosamine sulfate in human plasma by precolumn derivatization using high performance liquid chromatography with fluorescence detection: its application to a bioequivalence study.

A simple, rapid, selective and specific high-performance liquid chromatography (HPLC) method with fluorescence detection was developed for determination of glucosamine sulfate in human plasma and application to a bioequivalence in healthy volunteers. Precipitation of plasma was accomplished with acetonitrile to separate interfering endogenous products from the compound of interest. After vortex mixing and centrifugation, the supernatant was transferred and derivatized with 9-fluorenylmethoxycarbonyl chloride-acetonitrile solution in borate buffer (pH=8.0) at 30 degrees C for 30 min. The chromatographic separation was performed on a Diamonsil C18 column (150.0 mmx4.6 mm, 5 microm) with a mobile phase gradient consisting of water and acetonitrile at a flow rate of 1 mL/min. The method was linear in the range of 0.1-10.0 microg/mL with a correlation coefficient (r) of 0.9996. The limit of detection was 15 ng/mL. Inter- and intra-day precisions were <or=6.28 and 7.41%, respectively, and the accuracy ranged from 95.20 to 104.92%. Extraction recoveries of glucosamine sulfate from plasma were more than 90.4%. Plasma samples containing glucosamine sulfate were stable for 40 days at -20 degrees C and for 24 h after derivatization at 4 degrees C. The method was successfully applied to the bioequivalence study of glucosamine sulfate in healthy volunteers.

Administration, Oral↗

PubMed2004

Effect of glucosamine supplementation on fasting and non-fasting plasma glucose and serum insulin concentrations in healthy individuals.

OBJECTIVE: To test the hypothesis that glucose intolerance does not occur when healthy adults consume normal, recommended dosages of glucosamine sulfate. METHODS: Healthy adults (N=19) ingested 1500 mg of glucosamine sulfate or placebo (double blind) each day for 12 weeks. Three-hour oral glucose tolerance tests (OGTT) were performed using 75 g of dextrose. These occurred before the start of supplementation, at 6 weeks, and at the completion of supplementation (12 weeks). RESULTS: There were no significant differences between fasted levels of serum insulin or blood glucose. Glucosamine sulfate supplementation did not alter serum insulin or plasma glucose during the OGTT. There were no significant differences within or between treatments, ages or gender. Glycated hemoglobin measurements at the three time points showed no significant change over time, within or between treatments, ages or gender. The lack of significant changes may have been due to large standard deviations in the data. CONCLUSION: The data suggests that glucosamine supplementation, with normal recommended dosages, does not cause glucose intolerance in healthy adults. This cannot be determined conclusively, however, until further studies are conducted using alternative types of testing.

Adult↗

PubMed2005

Development of a simple analytical methodology for determination of glucosamine release from modified release matrix tablets.

A simple spectrophotometric method for determination of glucosamine release from sustained release (SR) hydrophilic matrix tablet based on reaction with ninhydrin is developed, optimized and validated. The purple color (Ruhemann purple) resulted from the reaction was stabilized and measured at 570 nm. The method optimization was essential as many procedural parameters influenced the accuracy of determination including the ninhydrin concentration, reaction time, pH, reaction temperature, purple color stability period, and glucosamine/ninhydrin ratio. Glucosamine tablets (600 mg) with different hydrophilic polymers were formulated and manufactured on a rotary press. Dissolution studies were conducted (USP 26) using deionized water at 37+/-0.2 degrees C with paddle rotation of 50 rpm, and samples were removed manually at appropriate time intervals. Under given optimized reaction conditions that appeared to be critical, glucosamine was quantitatively analyzed and the calibration curve in the range of 0.202-2.020 mg (r=0.9999) was constructed. The recovery rate of the developed method was 97.8-101.7% (n=6). Reproducible dissolution profiles were achieved from the dissolution studies performed on different glucosamine tablets. The developed method is easy to use, accurate and highly cost-effective for routine studies relative to HPLC and other techniques.

Algorithms↗

PubMed2001

Long-term effects of glucosamine sulphate on osteoarthritis progression: a randomised, placebo-controlled clinical trial.

BACKGROUND: Treatment of osteoarthritis is usually limited to short-term symptom control. We assessed the effects of the specific drug glucosamine sulphate on the long-term progression of osteoarthritis joint structure changes and symptoms. METHODS: We did a randomised, double-blind placebo controlled trial, in which 212 patients with knee osteoarthritis were randomly assigned 1500 mg sulphate oral glucosamine or placebo once daily for 3 years. Weightbearing, anteroposterior radiographs of each knee in full extension were taken at enrolment and after 1 and 3 years. Mean joint-space width of the medial compartment of the tibiofemoral joint was assessed by digital image analysis, whereas minimum joint-space width--ie, at the narrowest point--was measured by visual inspection with a magnifying lens. Symptoms were scored by the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index. FINDINGS: The 106 patients on placebo had a progressive joint-space narrowing, with a mean joint-space loss after 3 years of -0.31 mm (95% CI -0.48 to -0.13). There was no significant joint-space loss in the 106 patients on glucosamine sulphate: -0.06 mm (-0.22 to 0.09). Similar results were reported with minimum joint-space narrowing. As assessed by WOMAC scores, symptoms worsened slightly in patients on placebo compared with the improvement observed after treatment with glucosamine sulphate. There were no differences in safety or reasons for early withdrawal between the treatment and placebo groups. INTERPRETATION: The long-term combined structure-modifying and symptom-modifying effects of gluosamine sulphate suggest that it could be a disease modifying agent in osteoarthritis.

Administration, Oral↗

PubMed1998

Glucosamine-6-phosphate deaminase from beef kidney is an allosteric system of the V-type.

The enzyme glucosamine-6-phosphate deaminase from beef kidney has been purified to homogeneity by allosteric-site affinity chromatography. Its amino acid composition and the N-terminal sequence (1-42), were obtained. The amino acid sequence of this segment is essentially identical to the corresponding regions of the human and hamster glucosamine-6-phosphate deaminases. The beef enzyme is a hexamer of 32.5 kDa subunits; this is nearly 2.5 kDa higher than the molecular mass of the homologous enzyme from Escherichia coli. Beef kidney deaminase exhibits a notable difference from the bacterial enzyme in its allosteric activation by N-acetylglucosamine 6-phosphate This metabolite, which is also is the allosteric activator of the bacterial glucosamine-6-phosphate deaminase, activates the enzyme by increasing its kcat without any change in the Km values for glucosamine 6-phosphate, over a wide range of activator concentration. This observation places beef kidney deaminase in the class of V-type allosteric systems.

Aldose-Ketose Isomerases↗

PubMed1998

Enhanced synovial production of hyaluronic acid may explain rapid clinical response to high-dose glucosamine in osteoarthritis.

Anecdotal reports of rapid symptomatic response to high-dose glucosamine in osteoarthritis are not credibly explained by the traditional view that glucosamine promotes synthesis of cartilage proteoglycans. An alternative or additional possibility is that glucosamine stimulates synovial production of hyaluronic acid (HA), which is primarily responsible for the lubricating and shock-absorbing properties of synovial fluid. Many clinical and veterinary studies have shown that intra-articular injections of high-molecular-weight HA produce rapid pain relief and improved mobility in osteoarthritis. HA has anti-inflammatory and analgesic properties, and promotes anabolic behavior in chondrocytes. The concentration and molecular weight of synovial fluid HA are decreased in osteoarthritis; by reversing this abnormality, high-dose glucosamine may provide rapid symptomatic benefit, and in the longer term aid the repair of damaged cartilage.

Animals↗

PubMed1999

Determination of the nutraceutical, glucosamine hydrochloride, in raw materials, dosage forms and plasma using pre-column derivatization with ultraviolet HPLC.

A selective and specific high performance liquid chromatography method was developed to quantitate glucosamine hydrochloride in raw materials, dosage forms and plasma. Reverse phase chromatography using pre-column derivatization with phenylisothiocyanate, and ultraviolet detection (lambda = 254 nm) was used to quantify the eluate. The mobile phase consisted of MeOH/H2O/CH3COOH (10:89.6:0.04) and was pumped at a flow rate of 1.2 ml/min. The standard curves for glucosamine hydrochloride showed linearity (r > or = 0.99) over the selected concentration range from 6.65 to 16.63 microg/ml for raw materials and dosage forms. The precision of the dosage form assay, expressed as the % relative standard deviation (R.S.D.), was < 5% at all concentrations. The intra-day and inter-day accuracy, as indicated by the relative error (R.E.), ranged from - 2.54 to 2.70% for glucosamine hydrochloride. For the plasma assay, beagle dog plasma was used to prepare standard curves in the concentration range of 1.25-20 microg/ml. Precipitation of plasma proteins was accomplished with acetonitrile to separate interfering endogenous products from the compound of interest. The supernatant was derivatized using phenylisocyanate in phosphate buffer (pH = 8.3) and subsequently evaporated to dryness under a nitrogen stream at 42 degrees C. The residue was dissolved in 250 microl mobile phase and injected onto the chromatographic system. The assay was linear in concentration ranges of 1.25-20 microg/ml (r > or = 0.999). Intra- and inter-day precision was < or = 5.23 and 5.65%, respectively and the intra- and inter-day accuracy, indicated by R.E., ranged from - 8.6 to 10.35%. The method was found to be specific and with excellent linearity, accuracy and precision and is well suited for the quantitation of glucosamine hydrochloride in raw materials, dosage forms, and pharmacokinetic studies.

Acetonitriles↗