Glucosamine Group Research Articles

No effect of glucosamine sulfate on osteoarthritis in the temporomandibular joints—a randomized, controlled, short-term study

The aim of this study was to evaluate the clinical effects of oral glucosamine sulfate, compared with placebo, on osteoarthritis in the temporomandibular joints (TMJs). Fifty-nine patients, consecutive referrals fulfilling the research diagnostic criteria for temporomandibular disorder for TMJ osteoarthritis, confirmed roentgenographically, were randomized to the daily intake of 1,200 mg glucosamine sulfate or identical placebo capsules in this double-blind trial. Pain on visual and verbal rating scales and opening capacity were registered before and after 6 weeks of medication. The signs and symptoms were similar in the groups initially and they were ameliorated over time. No differences in improvement between groups after treatment were indicated. Eight patients in the glucosamine group and 2 in the placebo group stopped the medication prematurely. Gastrointestinal side effects were reported by a total of 10 and 3 patients, respectively. Oral glucosamine sulfate was not superior to placebo in reducing signs and symptoms of osteoarthritis in the TMJs in this short-term trial.

Intervention of Zhuanggu granule on IL-1β and TNF-α level of the patients with osteoarthritis

Objective To investigate the influence of Zhuanggu granule on the concentration of IL-1β and TN-F-α in knee cavity of patients with knee degenerated osteoarthritis. Methods A total of eighty patients with knee degenerated osteoarthritis were recruited into a Zhuanggu granule group (30 cases), a Sulphuric acid Glucosamine group (15 cases) and a Sodium Hyaluronate group (15 cases) according to Doll grouping method. After all groups were treated for 4 weeks, the changes of concentration of IL-1β and TNF-α was detected before and after the therapy Results After the treatment, the concentration of IL-1β and TNF-α in Zhuangu granule group was significantly lower than the other two groups (Sodium Hyaluronate and sulphuric Glucosamine group). Conclusion Zhuangu Granule could influence the concentration of IL-1β and TNF-α in patients of knee degenerated osteoarthritis. Key words: Knee degenerated osteoarthritis; Zhuangu granule; IL-1β; TNF-α

ChemInform Abstract: Potent Renin Inhibitory Peptides Containing Hydrophilic End Groups.

A previously reported renin inhibitor, Boc-Pro-Phe-N(Me)His-Leu psi [CHOHCH2]Val-Ile-Amp (U-71038), was altered by the incorporation of polar, hydrophilic moieties at either end, e.g., tris(hydroxymethyl)aminomethane (THAM) or glucosamine urea groups at the N-terminus, and the THAM amide or aminomethylpyridine N-oxide at the C-terminus. These modified analogues, with dramatically improved water solubility, all retained the potent renin inhibitory activity of U-71038 in vitro. The fact that good activity was maintained in these new analogues, which possess hydrophilicity and steric bulk considerably different from the parent compound, suggests that neither end of these molecules is critical for recognition and binding of the inhibitors by renin. These modified analogues were evaluated in a rat model, and several exhibited hypotensive activity after both oral and iv administration which was greater in magnitude and longer in duration than that caused by equimolar doses of U-71038. Furthermore, unlike U-71038, the oral activity of these analogues was not dependent upon administration in a citric acid vehicle.

Effect of Glucosamine on Pain-Related Disability in Patients With Chronic Low Back Pain and Degenerative Lumbar Osteoarthritis

Chronic low back pain (LBP) with degenerative lumbar osteoarthritis (OA) is widespread in the adult population. Although glucosamine is increasingly used by patients with chronic LBP, little is known about its effect in this setting. To investigate the effect of glucosamine in patients with chronic LBP and degenerative lumbar OA. A double-blind, randomized, placebo-controlled trial conducted at Oslo University Hospital Outpatient Clinic, Oslo, Norway, with 250 patients older than 25 years of age with chronic LBP (>6 months) and degenerative lumbar OA. Daily intake of 1500 mg of oral glucosamine (n = 125) or placebo (n = 125) for 6 months, with assessment of effect after the 6-month intervention period and at 1 year (6 months postintervention). The primary outcome was pain-related disability measured with the Roland Morris Disability Questionnaire (RMDQ). Secondary outcomes were numerical scores from pain-rating scales of patients at rest and during activity, and the quality-of-life EuroQol-5 Dimensions (EQ-5D) instrument. Data collection occurred during the intervention period at baseline, 6 weeks, 3 and 6 months, and again 6 months following the intervention at 1 year. Group differences were analyzed using linear mixed models analysis. At baseline, mean RMDQ scores were 9.2 (95% confidence interval [CI], 8.4-10.0) for glucosamine and 9.7 (95% CI, 8.9-10.5) for the placebo group (P = .37). At 6 months, the mean RMDQ score was the same for the glucosamine and placebo groups (5.0; 95% CI, 4.2-5.8). At 1 year, the mean RMDQ scores were 4.8 (95% CI, 3.9-5.6) for glucosamine and 5.5 (95% CI, 4.7-6.4) for the placebo group. No statistically significant difference in change between groups was found when assessed after the 6-month intervention period and at 1 year: RMDQ (P = .72), LBP at rest (P = .91), LBP during activity (P = .97), and quality-of-life EQ-5D (P = .20). Mild adverse events were reported in 40 patients in the glucosamine group and 46 in the placebo group (P = .48). Among patients with chronic LBP and degenerative lumbar OA, 6-month treatment with oral glucosamine compared with placebo did not result in reduced pain-related disability after the 6-month intervention and after 1-year follow-up. clinicaltrials.gov Identifier: NCT00404079.

Glucosamine sulfate reduces experimental osteoarthritis and nociception in rats: association with changes of mitogen-activated protein kinase in chondrocytes

To study the effects of oral glucosamine sulfate on the development of osteoarthritis (OA) and to examine concomitant changes in the nociceptive behavior of rats. OA was induced in Wistar rats by anterior cruciate ligament transection (ACLT) of the right knee; the left knee was untreated. The OA+glucosamine group received oral glucosamine sulfate (250 mg/kg/day) in a 2-g wafer once a day for 10 consecutive weeks starting at week 5 after ACLT. The OA group was treated as above with 2-g wafers (placebo). The control group of naïve rats received 2-g wafers only. The glucosamine alone group comprised naïve rats receiving glucosamine sulfate only. Nociceptive behavior (mechanical allodynia and weight-bearing distribution of hind paws) during OA development was analyzed pre- and 3, 6, 9, 12, 15, and 18 weeks post-ACLT. Macroscopic and histologic studies were then performed on the cartilage and synovia. Immunohistochemical analysis was performed to examine the effect of glucosamine on expression of mitogen-activated protein kinases (MAPKs) in the articular cartilage chondrocytes. OA rats receiving glucosamine showed a significantly lower degree of cartilage degeneration than the rats receiving placebo. Glucosamine treatment also suppressed synovitis. Mechanical allodynia and weight-bearing distribution studies showed significant improvement in the OA+glucosamine group as compared to the OA group. Moreover, glucosamine attenuated p38 and c-Jun N-terminal kinase (JNK) but increased extracellular signal-regulated kinase 1/2 (ERK) expression in OA-affected cartilage. Our results indicate that treatment with oral glucosamine sulfate in a rat OA model (1) attenuates the development of OA, (2) concomitantly reduces nociception, and (3) modulates chondrocyte metabolism, possibly through inhibition of cell p38 and JNK and increase of ERK expression.

Antibacterial chitosan-based blends with ethylene–vinyl alcohol copolymer

This study reports for the first time about the formulation, morphology, water barrier and the antimicrobial activity of high and low molecular weight chitosonium-acetate based solvent-cast blends with ethylene–vinyl alcohol (EVOH) copolymers. The blends based on the low molecular weight chitosan grade showed enhanced phase morphology, transparency, enhanced water barrier properties, up to 86% water permeability reduction compared to pure chitosonium-acetate films, as well as excellent antimicrobial activity. When the fraction of low molecular weight chitosan exceeded the phase inversion in the blend, phase segregation became noticeable but good interfacial adhesion was still observed. On the other hand, the blends with the high molecular weight chitosan grade were translucent, even when this component was in the dispersed phase, and exhibited clearly separated phase morphology but also presented antimicrobial performance. In both cases, and in accordance with previous works in our laboratory, the release from the blends of protonated glucosamine groups (so-called active species) correlated well with the antimicrobial phenomenology of the developed materials. The study also showed that EVOH copolymers can also be made antimicrobial by a water sorption-induced release mechanism, if acetic acid is incorporated into the polymer formulation before casting from solution. On the overall, antimicrobial chitosan-based blends with EVOH copolymers, when low molecular weight chitosan was used as the dispersed phase in the blend, exhibited optimum performance in terms of optical properties, water resistance, enhanced water barrier and, therefore, excellent application outlook in antimicrobial applications.

Glucosamine sulfate effect on the degenerated patellar cartilage: preliminary findings by pharmacokinetic magnetic resonance modeling

Normal and degenerated cartilages have different magnetic resonance (MR) capillary permeability (K(trans)) and interstitial interchangeable volume (v(e)). Our hypothesis was that glucosamine sulfate treatment modifies these neovascularity abnormalities in osteoarthritis. Sixteen patients with patella degeneration, randomly distributed into glucosamine or control groups, underwent two 1.5-Tesla dynamic contrast-enhanced MR imaging studies (treatment initiation and after 6 months). The pain visual analog scale (VAS) and American Knee Society (AKS) score were used. A two-compartment pharmacokinetic model was used. Percentages of variations (postreatment-pretreatment/pretreatment) were compared (t-test for independent data). In the glucosamine group, pain and functional outcomes statistically improved (VAS: 7.3 +/- 1.1 to 3.6 +/- 1.3, p < 0.001; AKS: 18.6 +/- 6.9 to 42.9 +/- 2.7, p < 0.01). Glucosamine significantly increased K(trans) at 6 months (-54.4 +/- 21.2% vs 126.7 +/- 56.9%, p < 0.001, control vs glucosamine). In conclusion, glucosamine sulfate decreases pain while improving functional outcome in patients with cartilage degeneration. Glucosamine sulfate increases K(trans), allowing its proposal as a surrogate imaging biomarker after 6 months of treatment.

Solid-state NMR studies of bacterial lipoteichoic acid adsorption on different surfaces

Teichoic acids are important to bacteria for surface adhesion, metal ion coordination, and other biological processes crucial to bacterial survival. In particular, the surface adhesion of teichoic acids plays a crucial role in the formation of Gram-positive biofilms. Biofilms have been implicated as the major cause of various chronic infections. Biofilm formation is essentially a four-step process beginning with the adhesion of bacteria to a surface, followed by the excretion of an extracellular polymeric substance (slime), development and maturation of the biofilm architecture, and finally biofilm spreading through bacterial release. Currently, there is very little molecular level information available for the initial adhesion of bacteria to solid surfaces. Solid-state NMR is ideally suited for the study of these samples, thus we use 31P solid-state NMR experiments to study the initial adhesion of lipoteichoic acid (LTA) to various surfaces. 31P CP-MAS spectra and T 1 ρ data demonstrate that the structure of LTA changes when adhered to cellulose, cell wall peptidoglycan (PGN), or TiO 2. However, when LTA is simultaneously adhered to PGN and TiO 2 the observed structure is dependent on the amount of retained water. For LTA on TiO 2, we suggest that the alanine and glucosamine groups interact with the surface. However, during simultaneous adhesion to TiO 2 and PGN, the glucosamine groups bind to the PGN while the alanine groups bind to the surface. This arrangement traps water between the PGN and TiO 2 surface.

A natural mineral supplement provides relief from knee osteoarthritis symptoms: a randomized controlled pilot trial

BackgroundThis small, pilot study evaluated the impact of treatment with a natural multi-mineral supplement from seaweed (Aquamin) on walking distance, pain and joint mobility in subjects with moderate to severe osteoarthritis of the knee.MethodsSubjects (n = 70) with moderate to severe osteoarthritis of the knee were randomized to four double-blinded treatments for 12 weeks: (a) Glucosamine sulfate (1500 mg/d); (b) Aquamin (2400 mg/d); (c) Combined treatment composed of Glucosamine sulfate (1500 mg/d) plus Aquamin (2400 mg/d) and (d) Placebo. Primary outcome measures were WOMAC scores and 6 Minute Walking Distances (6 MWD). Laboratory based blood tests were used as safety measures.ResultsFifty subjects completed the study and analysis of the data showed significant differences between the groups for changes in WOMAC pain scores over time (p = 0.009 ANCOVA); however, these data must be reviewed with caution since significant differences were found between the groups at baseline for WOMAC pain and stiffness scores (p = 0.0039 and p = 0.013, respectively, ANOVA). Only the Aquamin and Glucosamine groups demonstrated significant improvements in symptoms over the course of the study. The combination group (like the placebo group) did not show any significant improvements in OA symptoms in this trial. Within group analysis demonstrated significant improvements over time on treatment for the WOMAC pain, activity, composite and stiffness (Aquamin only) scores as well as the 6 minute walking distances for subjects in the Aquamin and Glucosamine treatment groups. The Aquamin and Glucosamine groups walked 101 feet (+7%) and 56 feet (+3.5%) extra respectively. All treatments were well tolerated and the adverse events profiles were not significantly different between the groups.ConclusionThis small preliminary study suggested that a multi mineral supplement (Aquamin) may reduce the pain and stiffness of osteoarthritis of the knee over 12 weeks of treatment and warrants further study.Trial registrationClinicalTrials.gov number: NCT00452101.

Characterization of antimicrobial properties on the growth of S. aureus of novel renewable blends of gliadins and chitosan of interest in food packaging and coating applications

The biocide properties of chitosan-based materials have been known for many years. However, typical antimicrobial formulations of chitosan, mostly chitosonium salts, are known to be very water sensitive materials which may impair their use in many application fields such as food packaging or food coating applications. This first work reports on the development and characterization of the antimicrobial properties of novel fully renewable blends of chitosan with more water-resistant gliadin proteins isolated from wheat gluten. Chitosan release to the nutrient broth from a wide range of blends was studied making use of the ninhydrin method. The results indicated that both pure chitosan and its blends with gliadins presented significant antimicrobial activity, which increased with increasing the amount of chitosan in the composite formulation as expected. The gliadins-chitosan blends showed good transparency and film-forming properties and better water resistance than pure chitosan. The release tests revealed that dissolution of the biocide glucosamine groups, i.e. the chitosan water soluble fractions, also increased with the amount of chitosan present in the formulation. The release of these groups was for the first time directly correlated with the antimicrobial properties exhibited by the blends. Thus, incorporation of chitosan into an insoluble biopolymer matrix was revealed as a very feasible strategy to generate novel chitosan-based antimicrobial materials with potential advantages, for instance active food packaging applications.

Polyelectrolyte Complexes from Polysaccharides: Formation and Stoichiometry Monitoring

Colloids were obtained from non-stoichiometric polyelectrolyte complexes with two polysaccharides of opposite charge: chitosan and dextran sulfate (DS) as the polycation and polyanion, respectively. The complexes were elaborated by a one-shot addition of the polymer in default to the one in excess. The colloids were positively or negatively charged according to the nature of the polymer in excess. Dynamic light scattering (DLS) demonstrated that particles were formed at a very early stage in the complexation process. The consumption of the excess polyelectrolyte was monitored with a dye assay specific for dextran sulfate (toluidine blue) or chitosan (orange II). From these experiments, two different mechanisms of colloidal PEC formation were evidenced, according to the nature of the polymer in excess. On adding chitosan to DS in excess, regular consumption of the polyanion was observed at a constant stoichiometry, in the 1.5 to 1.85 range (sulfate residues for one glucosamine group), according to the molar mass of the polycation. When DS was added to chitosan in excess, the overall stoichiometry varied from ca. 6 (glucosamine residues for one sulfate group) down to 1 as the charge molar mixing ratio R=n+/n- decreased from 20 to 1. The existence of various mechanisms, according to the nature of the polymer in excess, could be attributed to the differences in chemical reactivity (strong vs low) of the ion in excess and the conformation and flexibility of the macromolecular chains related to their electrostatic potential.

GLUCOSAMINE ADMINISTRATION IMPROVES SURVIVAL RATE AFTER SEVERE HEMORRHAGIC SHOCK COMBINED WITH TRAUMA IN RATS

We have previously shown that glucosamine administration resulted in higher cardiac output and improved tissue perfusion after trauma-hemorrhage with resuscitation in rats, which was associated with the increased levels of protein O-linked-N-acetylglucosamine (O-GlcNAc). The purpose of the study was to evaluate the effect of glucosamine on the survival, without resuscitation, in rats. Adult male rats underwent midline laparotomy and 55% of total blood volume was withdrawn for 25 min under isoflurane anesthesia. At the end of the hemorrhage period, 2.5 mL of 150 mM glucosamine or equivalent osmolarity of mannitol solution was injected intravenously for 10 min. The survival time, mean blood pressure, heart rate, and central body temperature were monitored continuously; then, the O-GlcNAc levels in heart, brain, liver, and muscle were measured by means of Western blot analysis. Glucosamine administration significantly increased the survival rate in comparison with mannitol administration (percentage of survival after 2 h, 47% vs. 20%; P < 0.05). The mean arterial pressure was significantly higher in the glucosamine group for 18 min after treatment. The protein O-GlcNAc levels, assessed 30 min after glucosamine treatment, were significantly increased in the heart, brain, and liver. These data demonstrate that i.v. glucosamine administration improves the survival rate after trauma-hemorrhage without resuscitation; this effect may be related to the glucosamine-induced increase in protein O-glycosylation. Furthermore, the increase in mean arterial pressure may suggest a vasoactive and/or positive inotropic effect of glucosamine in hypovolemic shock.

Glucosamine Administration in Athletes: Effects on Recovery of Acute Knee Injury

The main aim of this study was to examine the effects of 4 weeks of glucosamine administration on the functional ability and the degree of pain intensity in competitive male athletes after acute knee injury. This study was a randomized, double-blind parallel trial of glucosamine (1500 mg per day) or a placebo for 28 days, utilising 106 patients with an acute knee injury. Pain and functional ability were evaluated at the beginning of the study and at 7, 14, 21, and 28 days after starting treatment. Pain intensity at rest and while walking was assessed using a visual analog scale. Passive knee flexibility (flexion and extension) of the injured limb was measured using a modified goniometer, and the degree of knee swelling was measured and compared with the noninjured limb. No significant difference was found between the glucosamine, and placebo group in mean pain intensity scores for resting and walking, and degree of knee swelling at the 7-day, 14-day, 21-day, and 28-day assessment. There was no significant difference between passive knee flexibility at the 7-day, 14-day, and 21-day assessment. After 28 days of treatment the patients from the glucosamine group demonstrated significant improvement in knee flexion and extension as compared with the placebo group.

Effects of glucosamine administration on patients with rheumatoid arthritis

The purpose of this study was to examine whether glucosamine has an antirheumatic effect in a randomized placebo-controlled study. The subjects were 51 rheumatoid arthritis (RA) patients: 25 patients in the glucosamine group and 26 patients in the placebo group. Glucosamine hydrochloride at a daily dose of 1,500 mg and placebo, respectively, were administered for 12 weeks along with conventional medication. While significant improvement was not found in joint counts and in the rate of ACR20 responders, the face scale and a visual analogue scale pain were significantly in favor of the glucosamine group. ESR and CRP levels did not change, but serum MMP-3 levels decreased in the glucosamine group. Results of the patients' self-evaluations and the physicians' global evaluations indicated that the glucosamine treatment produced noticeable improvements in symptoms. Although glucosamine administration had no antirheumatic effect evaluated by conventional measures, it seemed to have some symptomatic effects on RA.

Glucosamine administration improves survival following trauma‐hemorrhage in rats

We have previously shown that glucosamine improved cardiac output and organ perfusion following trauma-hemorrhage and resuscitation in rats, and this was associated with increased levels of N-acetyl-glucosamine (O-GlcNAc) on proteins. The purpose of this study was to determine whether glucosamine improved survival in a model of hypovolemic shock without resuscitation. Food deprived male rats underwent midline laparotomy, and 55% of total blood volume was withdrawn in 25 minutes under isoflurane anesthesia. At the end of hemorrhage 2.5 mL of 150 mM glucosamine or equivalent osmolarity of mannitol were injected i.v. over 10 minutes. Survival time, blood pressure, heart rate and central body temperature were monitored continuously. Glucosamine administration significantly increased the survival rate 2 hours following hemorrhage, compared with the mannitol treated rats (47% vs. 20%, p<0.05). Mean arterial pressure (MAP) was significantly higher in the glucosamine group at the end of, and 15 minutes after treatment (60±8 vs. 39±5 mmHg, p<0.05 and 45±6 vs. 27±4 mmHg, p<0.05). There were no differences in heart rate between groups. Our results demonstrate that glucosamine administration improves survival following trauma-hemorrhage without resuscitation. Further studies are required to determine whether the protective effect of glucosamine is mediated via an increase in protein O-GlcNAc levels and if this contributes to the increased MAP. This study was supported by NIH grant HL076165.

Development of Functional Fish Feed with Natural Ingredients to Control Heavy Metals

The effects of two natural ingredients, Chinese parsley (CP) and chitosan (CT), on growth, accumulation, and excretion of cadmium in fish body and preservation of essential trace metals in the body were investigated by using rainbow trout that had been fed cadmium-added diet, low and high concentration, for 3 weeks. This pretest confirmed that cadmium was accumulated in the liver, kidney, and intestine of the test fish. The cadmium level of the fish, fed diet with CP or CT, was decreased by 18% and 24%, respectively, compared to that of the fish given the control diet. But CP and CT did not have an influence on normal growth of test fish and the levels of essential trace metals in the body. In addition, the level of cadmium was higher in liver than kidney in the high-cadmium dietary group, indicating the Cd level in kidney follows that of liver as kidney lies in the final stage of metabolism. The cadmium accumulation in the fish body was supposed to be reduced, by giving CP to increase the solubility of Cd to body fluid by conjugation into metallothioneins (MTs), while CT was supposed to be responsible for the physical adsorption of cadmium ions by glucosamine groups.

Effect of urea on solution behavior and heat-induced gelationof chitosan-β-glycerophosphate

In this study, we have investigated the effect of urea on the physicochemical (pH and conductivity) and rheological properties of the chitosan- β-GP system in order to assess the main polymer–polymer interactions at low and high temperature. The pH of the solutions was slightly increased due to the consumption of H + in solution through the hydrolysis of urea. Furthermore, the addition of urea considerably decreased the conductivity, and therefore the ionic strength of the solutions, and this effect was more important at high temperature. It indicated that urea strongly affects polymer–polymer interactions by weakening hydrogen bonds at low temperature, but in addition can hinder hydrophobic effect at high temperature since the reduction of ionic strength results in less screening of electrostatic repulsion between protonated glucosamine groups. At 15 °C, the addition of urea to chitosan- β-GP solutions decreased their elasticity, shortened relaxation times and simplified the relaxation process due to the disruption of hydrogen bonds. Heat-induced gelation of the chitosan system in the presence of urea showed higher gelation temperature ( T gel) in non-isothermal tests and longer gelation time ( t gel) in isothermal conditions. The activation energy for gelation also increased with increasing urea concentration. We concluded that the detrimental effect of urea on the gelation process was mainly related to a decrease in polymer-polymer hydrophobic effect, as shown by the decrease in conductivity.

Effect of oral glucosamine on cartilage degradation in a rabbit model of osteoarthritis

To determine whether oral glucosamine alleviates cartilage degradation in an animal model of osteoarthritis (OA). The effect of 8 weeks of daily oral glucosamine hydrochloride on degeneration of articular cartilage was evaluated in rabbits in which anterior cruciate ligament transection (ACLT) was performed to induce OA. Animals were treated with glucosamine (n = 16) or a placebo (n = 16) and necropsied at 11 weeks. Seven unoperated rabbits served as controls. The articular cartilage was evaluated macroscopically and histologically and analyzed for total type II collagen and glycosaminoglycan (GAG) content. Histologic analysis revealed that loss of proteoglycan, based on Safranin O-fast green staining, was significantly reduced in the lateral tibial plateau cartilage of ACL-transected limbs in the glucosamine group compared with ACL-transected limbs in the placebo group, with a similar, but not significant, trend for the lateral femoral condylar cartilage. Likewise, macroscopic analysis of cartilage showed that the lateral tibial plateau alone had a significantly lower rate of disease in the glucosamine group, which was consistent with the results of the independent histologic assessment. However, no significant treatment effect was detected when composite histologic scores were analyzed. A significant reduction in GAG content was observed in the femoral condyles of placebo-treated ACL-transected joints, but not in the same region of glucosamine-treated ACL-transected joints, compared with their respective contralateral unoperated joints. Oral administration of glucosamine had a detectable, site-specific, partial disease-modifying effect in this model of OA. From a clinical perspective, the administration of glucosamine did not prevent fibrillation and/or erosions of the articular cartilage in all of the treated animals, and no effects were detected in the medial joint compartments.

Synergistic antiinflammatory effects of pinitol and glucosamine in rats

This study evaluated the antiinflammatory activities of pinitol and glucosamine either alone or in combination against carrageenan- and cotton pellet-induced acute and subacute inflammation in rats. Five groups were included in each of the acute and subacute inflammation studies: the vehicle control group, positive control group (aminopyrine 100 mg/kg), pinitol group (20 mg/kg), glucosamine group (25 mg/kg) and a pinitol (20 mg/kg) and glucosamine (25 mg/kg) combination group. When 20 mg/kg of pinitol was administered to the rats, paw edema induced by the carrageenan injection was significantly suppressed and the level of granuloma formation induced by the cotton pellet implantation was slightly reduced. When 25 mg/kg of glucosamine was administered, paw edema caused by the acute inflammation was slightly reduced and the level of granuloma formation caused by the subacute inflammation was strongly suppressed. Although the combined application of pinitol and glucosamine did not have an additional antiinflammatory effect on the paw edema caused by acute inflammation, it did have an increased antiinflammatory effect on the formation of granuloma induced by subacute inflammation. Therefore, pinitol and glucosamine have an antiinflammatory effect on acute and subacute conditions. Moreover, a synergistic antiinflammatory effect against subacute inflammation was observed when the two chemicals were administered in combination.

Physicochemical characterization of chitosan nanoparticles: electrokinetic and stability behavior

Some physical properties of nanogel particles formed by chitosan ionically cross-linked by tripolyphosphate (TPP) have been studied. Electrokinetic properties and colloidal stability were analyzed as a function of pH and ionic strength of the medium. Chitosan particles showed volume phase transitions (swelling/shrinking processes) when the physicochemical conditions of the medium were changed. Experimental data were mainly obtained by electrophoretic mobility measurements and by photon correlation spectroscopy and static light scattering techniques. Chitosan chains possess glucosamine groups that can be deprotonated if the pH increases. Therefore, modification of pH from acid to basic values caused a deswelling process based on a reduction of the intramolecular electric repulsions inside the particle mesh. Electrophoretic mobility data helped to corroborate the above electrical mechanism as responsible for the size changes. Additionally, at those pH values around the isoelectric point of the chitosan–TPP particles, the system became colloidally unstable. Ionic strength variations also induced important structural changes. In this case, the presence of KCl at low and moderate concentrations provoked swelling, which rapidly turned on particle disintegration due to the weakness of chitosan–TPP ionic interactions. These last results were in good agreement with the predictions of gel swelling theory by salt in partially ionized networks.