Synthesis And Biological Evaluation Of Cholic Modified Glucosamine Derivatives

D-Glucosamine is a natural marine product with marine biological activity, which is ableto participate in detoxification of liver and kidney, inhibit growth of cancer cell, act asantimicrobial, prevent food from rotting, and it has a very wide range applications inphysiology, medicine, food science. Among these, D-glucosamine has a very important role inthe therapeutic areas of cartilage, not only it can be used as a drug for treatment ofosteoarthritis, but also it has a variety of derivatives, which have a wide range of differentphysiological activities and can be used as biomaterials for cartilage repairing. Thus, byintroducing special structure into the structure of D-glucosamine with molecular design theory,it has very important significance for the application of derivatives of D-Glucosamine incartilage repairing.Cholic acid is a natural steroid derived from the human body, which is able to participatein digestive process and prevent the formation of cholesterol gallstones, and has a greatsignificance for the human body. Cholic acid has a unique molecule structure with ahydrophobic inner concave surface and a hydrophilic outer convex surface, and it is aamphiphilic molecules which can be used as a modifying groups to be introduced into thestructure of D-glucosamine to prepare a new derivative, which is able to adjust the balance ofhydrophilic and hydrophobic of biomedical materials for cartilage repairing, and it has a veryimportant significance.In this study, Cholic acid is used to modify D-glucosamine to prepare two newcompounds, which is called N-cholicacyl-D-Glucosamine (CAGA) and3-acryloyl-24-cholicacyl-D-Glucosamine (ACAGA), and the structure of these two compounds is characterized by1H-NMR, FT-IR, HPLC, MS.Secondly, D-glucosamine derivatives will eventually interact with the protein either as adrug for treatment of osteoarthritis or as biomedical materials for cartilage repairing.Therefore, with N-cholicacyl-D-Glucosamine (CAGA),3-acryloyl-24-cholicacyl-D-Glucosamine (ACAGA), N-acryloyl-glucosamine (AGA), N-acetyl-glucosamine(aceGA), we use bovine serum albumin (BSA) as a model protein to study the interaction ofBSA and the four derivatives of D-glucosamine. The results show that four kinds ofGlucosamine derivatives and BSA are generated stable ground state complex, fluorescencequenches by static quenching mechanism. CAGA, ACAGA has two BSA binding sites, while AGA, aceGA has one BSA binding sites, and the binding constant of the former is slightlylarger than that of the latter. Four glucosamine derivatives cause the effect on the secondarystructure of BSA, wherein-helix, β-fold, β-angle decrease in the percentage, while randomcoils increases. In addition, four glucosamine derivatives cause the effect onmicroenvironment of amino acid residues of BSA. The addition of four glucosaminederivatives increase the polarity of microenvironment of tryptophan residues, reducehydrophobicity, and the hydrophobic cavity structure has slightly collapsed. By computing,and true distance r between the phosphor (Glucosamine) and the quencher (tryptophanresidues) is calculated, and meet the Forster energy transfer theory.Thirdly, we carry out biological evaluation on these two derivatives by cytotoxicity, cellproliferation, live&dead cell staining. The results showed that concentration of CAGA below0.8mM has no negative impact on the cytotoxicity and the growth and proliferation of L929,and that concentration of CAGA between0.5-3mM had some impact, but the inhibitoryeffect was not sustained, approximately about3days, and after inhibition of time, more rapidrate than the former value suppression. Saturated solution and the corresponding dilution ofACAGA has no negative impact on the cytotoxicity and the growth and proliferation of L929.