About Glucosamine

Glucosamine is the most abundant naturally occurring amino sugar in which one or more nonglycosidic hydroxyl groups are replaced by an amino or substituted amino group. Glucosamine is a glucose substituted at the 2 position. It is present in peptidoglycans and variety of complex polysaccharides such as blood group substances. It is generally acetylated (N-acetylglucosamine). It is the basic structural unit of chitin which is a linear unbranched homopolymer composed of N-acetyl-D-glucosamine residues in beta-linkage (1,4) like cellulose.

Chitin is the principal constituent of arthropod exoskeletons to cover the surface of the body, found mainly in crab, lobster or shrimp shell. Chitin is also found in the cell walls of some fungi. Muramic acid is a compound consisting of glucosamine and lactic acid joined by an ether linkage. It is the characteristic polysaccharide composing bacterial cell walls. Chitosan is the de-acetylation form of chitin; a polysaccharide composed of repeating glucosamine units. It is used to absorb heavy metals in water treatment. Chondroitin is a glycosaminoglycan composed of a sulfated (C-4 or C-6) N-acetylgalactosamine residue linked to a glucuronic acid residue. It consists of repeating disaccharide units.

Glucsoamine is abundant in connective tissues, particularly in the ground substance of blood vessels, bone, and cartilage. Chondroitin sulfate A is sulfated on C-4 position and called also chondroitin 4-sulfate to dominate the position of the sulfate group on the sugar, while Chondroitin sulfate C is chondroitin 6-sulfate. Chondroitin sulfate B is another name of dermatan sulfate which is sulfated on the C-4 position but also the C-5 of the uronic acid is under the epimerisation of glucuronic acid to iduronic acid. Glucosamine and chondroitin sulfate are being tested for potential benefit in osteoarthritis. They are stabilizd with hydrochloride or sulfur to be used as dietary or nutritional supplements.

Glucosamine sulphate and glucosamine hydrochloride are nutritional supplements. Animal studies have found that glucosamine can both delay the breakdown of and repair damaged cartilage. The results for the use of glucosamine for osteoarthritis are mixed and the size of the effect is modest. There's some evidence that more recent trials and those using higher-quality methods are less likely to show a benefit. Evidence from trials on glucosamine hydrochloride is scarce and not convincing.

What is it?

Family: Nutritional supplement

Scientific name: Glucosamine sulphate, glucosamine hydrochloride

Other names: GS, amino monosaccharide, sulfated monosaccharide, chitosamine, D-glucosamine

Glucosamine is an amino sugar made from shellfish or prepared in the laboratory. It's available in two forms: glucosamine sulphate and glucosamine hydrochloride. You can buy both from high-street retailers.

How does it work?

Glucosamine is found naturally in your body. It plays an important role in making glycosaminoglycans and glycoproteins, which are essential building blocks of many parts of your joints, including ligaments, tendons, cartilage and synovial fluid. It's been suggested that the way these parts of your joint are built and maintained contributes to the development and the progression of osteoarthritis.

Glucosamine Hydrochloride :

Animal studies have found that giving glucosamine can delay the breakdown of cartilage as well as rebuild it.

1.1956 -The first major paper entitled "Effect of Hexosamines on the Synthesis of Chondroitin sulphuric acid in vitro" by Lennart Roden of the Karolinska Institute (Stockholm, Sweden) was published in Arkiv for Kemi (Band 10 nr 23).

This benchmark work involved Glucosamine HCl and Galactosamine HCl and showed that Glucosamine HCl stimulated production of Chondroitin Sulfate in slices of cartilage by as much as 250 to 320% of the control value. Under identical circumstances, Galactosamine only stimulated production of chondroitin sulfate by only twice the control value.

2.1971 - The second significant paper entitled "Effects of Hexosamine Derivatives and Uronic Acid Derivatives on Glycosaminoglycane Metabolism of Fibroblast Cultures" by Karzel et al at the Institute of Pharmacology, University of Bonn was published In Pharmacology 5: 337-345 (1971). Karzel studied the effects of Glucosamine HCl, Glucosamine Iodide and Glucosamine Sulfate on the secretion of mucopolysaccharide (aka glycosaminoglycan) of murine embryonic fibroblast monolayer cultures. This work showed clearly that glucosamine and the glucosamine derivatives (Glucosamine HCl, Glucosamine Iodide and Glucosamine Sulfate) are capable of enhancing the release and probably the production of mucopolysaccharides by fibroblasts in vitro. The data further shows that, on a weight to weight basis, Glucosamine HCl seems to possess a somewhat stronger effect then either Glucosamine Sulfate or Glucosamine Iodide.

3.1974 -The third paper of interest entitled "Effect of D-Glucosamine Concentration on the Kinetics of Mucopolysaccharide Biosynthesis in Cultured Chick Embryo Vertebral Cartilage" by Kim & Conrad (Dept. of Biochemistry, University of Illinois, Urbana, IL) was published in The Journal of Biological Chemistry (Vol. 249, No. 10, Issue of May 25, pp. 3091-3097, 1974).

The work utilizes C14-tagged Glucosamine HCl and C14-tagged Galactosamine HCl and measures the effect of both on the rate of chondroitin sulfate synthesis in the specified cultures. Kim was able to show that the tagged glucosamine hydrochloride not only has a pronounced effect on hyaluronic acid and chondroitin sulfate synthesis but is incorporated into chondroitin sulfate at 10 times the rate of the tagged galactosamine. No sulfur source was added to any of the cultures tested.

(NOTE: Hyaluronic Acid consists of repetitive units of glucosamine-uronic acid while chondroitin sulfate consists of repetitive units of galactosamine-uronic acid. Glucosamine is incorporated into chondroitin sulfate only after conversion from glucosamine to galactosamine during biosynthesis)

4.1978 - The fourth paper entitled "Articular Cartilage Pharmacology: I. InVitro Studies on Glucosamine and Non Steroidal Anti-inflammatory Drugs" by Plana et al (Rotta Research Laboratories S.p.A, Milan, Italy) was published in Pharmacological Research Communications, Vol. 10, No. 6, 1978.Plana worked exclusively with Glucosamine HCl and was able to show that Glucosamine HCl stimulates in a dose dependent manner soluble mucopolysaccharide release by "in vitro" cultured mouse fibroblasts. According to Plana, Karzel in agreement with those reports these results. Plana further showed that the dose-dependent enhancing activity of Glucosamine HCl not only contrasted to the dose-dependent depressing activity of non-steroidal anti-inflammatory drugs but also could diminish in a statistically significant way the depressing activity of the NSAID on protein and mucopolysaccharide synthesis.

Clinical studies reveal:

Glucosamine sulphate trials for osteoarthritis

A review article of 18 trials investigating the effectiveness of glucosamine sulphate in treating osteoarthritis was published in 2005. A further four trials published since 2007 evaluated the effect of glucosamine sulphate in the treatment of hip and knee osteoarthritis. A second review article compared the clinical effectiveness and safety of glucosamine sulphate with those of non-steroidal anti-inflammatory drugs (NSAIDs).

Review article (2005)

The number of participants in the RCTs included in this article ranged from 30 to 319. The trials lasted from three weeks to three years.

1. Seven trials out of 13 which compared glucosamine sulphate to a placebo found that the glucosamine sulphate was significantly better than the placebo in relieving pain.

2. In all 13 RCTs, the number and severity of side-effects reported by participants who were given glucosamine sulphate weren't significantly different from those reported by participants who got the placebo.

3. Three trials out of five found that glucosamine sulphate was significantly better than the placebo in improving problems associated with walking and other daily activities.