Chondroprotective, anti-inflammatory and anti-platelet actions of glucosamine

Abstract

  Glucosamine, a naturally occurring amino monosaccharide, has been widely used to treat osteoarthritis in humans. Several clinical trials have shown the significant symptom-modifying effect of glucosamine on osteoarthritis. Administration of glucosamine normalizes cartilage metabolism, so as to inhibit the degradation and stimulate the synthesis of proteoglycans, and to restore the articular function. In addition to the chondroprotective action, glucosamine is expected to exhibit anti-inflammatory actions by suppressing neutrophil functions such as superoxide generation, phagocytosis, granule enzyme release and chemotaxis. Moreover, glucosamine has been demonstrated to suppress the progression of adjuvant arthritis (a model of rheumatoid arthritis) possibly by inhibiting synovial cell activation and production of inflammatory mediators (such as prostaglandin E₂ and nitric oxide). Finally, glucosamine can suppress platelet aggregation, release of granule constituents, thromboxane A₂ production, calcium mobilization and phosphorylation of Syk possibly via the inhibition of ADP-binding to the receptors. Thus, glucosamine could be expected as a novel anti-platelet agent for thrombotic disorders due to its suppressive actions on platelets.