China
Africa
Explore chapters and articles related to this topic
Glycosaminoglycans
Published in Luke R. Bucci, Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Glucosamine is a naturally occurring aminosugar found in glycoproteins and glycosaminoglycans. Glucosamine itself constitutes half of hyaluronan, keratan sulfates, heparan sulfates, and heparin. Epimerases easily convert glucosamine into galactosamine, which constitutes half of chondroitin sulfates and dermatan sulfates (see Table 1). It is entirely logical to extend the results from studies of long-chain glycosaminoglycans to their precursors, including glucosamine. Prudden and co-workers, from Columbia University in New York, attempted to isolate the active part of their cartilage powders that conferred an acceleration of wound healing after topical application to surgical wounds.1302 After analysis of cartilage batches that differed in ability to accelerate wound healing, the major difference was more glucosamine in the more successful batch. Therefore, glucosamine and Af-acetylglucosamine, both topical and parenteral, were applied to rat surgical wounds, and a slight increase in wound strength (3 to 10%) was found. However, topical application of insoluble chitin — a long-chain, linear polymer of N-acetylglucosamine — was associated with a 30% increase in wound tensile strength, which was greater than the increase from cartilage powders. This effect was explained by the large amount of Iysozyme in healing wounds, which presumably degraded chitin into N-acetylglucosamine in situ in large quantities at the wound site. Increased availability of glucosamine would then accelerate or enhance synthesis of new HA, GAGs, and PGs.
Critical Appraisal of Animal Models for Antibiotic Toxicity
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Patricia D. Williams, Girard H. Hottendorf
Aminoglycosides represent an important class of antibiotics used clinically to treat gram-negative infections, often life-threatening in nature. This class includes such compounds as neomycin, gentamicin, tobramycin, amikacin, kanamycin, and netilmicin. Structurally, they consist of amino sugars linked to another moiety by a glycoside bond. Aminoglycoside-induced nephrotoxicity is well-documented in the human, with incidences ranging from 2 to 36% of patients receiving the drug [11–15]. In fact, aminoglycosides are the leading cause of antibiotic-induced acute renal failure [16]. Proximal tubule necrosis is a consistent feature of aminoglycoside nephrotoxicity in humans and experimental animals, primarily involving the pars convoluta of the proximal nephron [17–19].
Techniques for Isolation and Evaluation
Published in Shojiro Inoué, Biology of Sleep Substances, 2020
After chromatography on SP-Sephadex® (steps 6 and 7), several adjacent eluates were found to be active. Each was taken separately through the remainder of the purification program. Acid hydrolysis of the final purified fractions released glutamic acid (Glu), alanine (Ala), diaminopimelic acid (Dap), and glycine. The apparent molar ratios of Glu/Ala/Dap were 2:2:1. Since Dap is a constituent of bacterial peptideglycans, Krueger et al.48 supposed that their purified fractions might contain amino sugars. The sample was then subjected to mild acid hydrolysis, followed by amino acid analysis. Thus, it was determined that muramic acid was equimolar with Dap, whereas glucosamine was equimolar with glycine. Hence, urinary Factor S was proven to be a small glycopeptide.
Pre-clinical investigation of protective effect of nutraceutical D-glucosamine on TNBS-induced colitis
Published in Immunopharmacology and Immunotoxicology, 2023
Supriya Roy, Suneela Dhaneshwar, Tarique Mahmood, Swatantra Kumar, Shailendra K. Saxena
IBD is a multi-factorial ailment as it is provoked by various factors such as genetic, environmental, and immunological factors. The extensive literature review has revealed that amino sugars play a vital role in resisting chemical attacks and improving the tenacity of colon mucus. Mucosal glycoprotein and mucus synthesis are involved in maintaining the cytoarchitecture of colonic mucosa through their cytoprotective effect. Deficient or impaired glycoprotein biosynthesis due to suppressed NAG levels is implicated in the pathogenesis of IBD. It is also manifested that mediators like TNF-alpha, IL, and oxidative stress play a significant role in the amplification of inflammation as well as the transition of the normal epithelium to intestinal fibrosis [35]. Since these mediators are implicated in the pathogenesis of IBD, present work aimed at targeting these mediators to investigate the potential of D-GLU for repurposing in the management of IBD. It was thought that the outcome of this study may lead to a better understanding of the role of inflammatory factors in early pathogenic events prior to the development of fibrosis and which inflammatory markers could be the main triggers of cellular and histological modifications.
Synthesis, biological evaluation, and in silico studies of new CDK2 inhibitors based on pyrazolo[3,4-d]pyrimidine and pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine scaffold with apoptotic activity
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Asmaa A. Mandour, Ibrahim F. Nassar, Mohammed T. Abdel Aal, Mahmoud A. E. Shahin, Wael A. El-Sayed, Maghawry Hegazy, Amr Mohamed Yehia, Ahmed Ismail, Mohamed Hagras, Eslam B. Elkaeed, Hanan M. Refaat, Nasser S. M. Ismail
5-Amino-1-(4-fluorophenyl)glycyl)-1H-pyrazole-4-carbonitrile 2, was prepared by the reaction of 2-((4-fluorophenyl)amino)acetohydrazide 1 with ethoxymethylene malononitrile in ethanol under reflux. The isolated brown solid 2 was then treated with triethoxyorthoformate in acetic anhydride to afford ethyl-N-(4-cyano-1-((4-fluorophenyl)glycyl)-1H-pyrazol-5-yl)formimidate 3. The key starting material pyrazolopyrimidine 4 was obtained by treatment of the formimidate derivative 3 with hydrazine hydrate in ethanol. Subsequent reaction of pyrazolopyrimidine 4 with sugar aldoses namely; D-glucose and D-xylose, in the presence of a catalytic amount of acetic acid, afforded the amino-sugar products 5 and 6 respectively (Scheme 1). The structures of this set of novel amino sugars were confirmed by their spectral and elemental analysis data (see Experimental Section). 1H NMR spectra of the amino-sugar compounds 5 and 6 showed a signal attributed to H-1 at 5.13 and 5.10 ppm confirming the sp3 hybridisation of its corresponding carbon (C-1) and the cyclic form of the sugar moiety which agrees well with the reported results for such type of compounds following such mode of preparation36.
Isolation, characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali
Published in Pharmaceutical Biology, 2022
Adama Dénou, Adiaratou Togola, Kari Tvete Inngjerdingen, Nastaran Moussavi, Frode Rise, Yuan Feng Zou, Dalen G. Dafam, Elijah I. Nep, Abubakar Ahmed, Taiwo E. Alemika, Drissa Diallo, Rokia Sanogo, Berit Smestad Paulsen
Currently, bioactive phytocompounds have received great attention because of their vital health-related activities, such as antimicrobial, antioxidant, anticoagulant and antidiabetic activities, UV protection, antiviral and hypoglycaemic activities, etc. (Ullah et al. 2019). Among these components, carbohydrates known as saccharides are molecules consisting of carbon, hydrogen, and oxygen. They can also be sulphated and contain amino sugars. Carbohydrates such as monosaccharides, oligosaccharides and polysaccharides represent the most abundant biomolecules and essential components of many natural products and have attracted the attention of researchers because of their numerous human health benefits (Ruocco et al. 2016). Malian antimalarial plants contain polysaccharides (Dénou et al. 2019). From the outcomes of the polysaccharide screening on antimalarial plants used in Mali, Argemone mexicana was selected for deep investigations of its bioactive polysaccharides.