Glycan Carriers As Glycotools for Medicinal Chemistry Applications

Amino acid modified OCMC-g-Suc-β-CD nanohydrogels carrying lapatinib and ginsenoside Rg1 exhibit high anticancer activity in a zebrafish model

Nanohydrogels show great potential as efficient drug carriers due to their biocompatibility, low toxicity, and high water absorbability. In this paper, we prepared two O-carboxymethylated chitosan (OCMC)-based polymers functionalized with β-cyclodextrin (β-CD) and amino acid. The structures of the polymers were characterized by Fourier Transform Infrared (FTIR) Spectroscopy. Morphological study was carried out on a Transmission Electron Microscope (TEM), and the results indicated that the two polymers had irregular spheroidal structure with some pores distributed on their surface. The average particle diameter was below 500 nm, and the zeta potential was above +30 mV. The two polymers were further used for preparing nanohydrogels loaded with anticancer drugs lapatinib and ginsenoside Rg1, and the resulting nanohydrogels showed high drug loading efficiency and pH-sensitive (pH = 4.5) drug release behavior. In vitro cytotoxicity investigation revealed that the nanohydrogels exhibited high cytotoxicity against lung cancer (A549) cells. In vivo anticancer investigation was performed in a transgenic Tg(fabp10:rtTA2s-M2; TRE2:EGFP-kras ^V12) zebrafish model. The results showed that the synthesized nanohydrogels significantly inhibited the expression of EGFP-kras ^v12 oncogene in zebrafish liver, and the L-arginine modified OCMC-g-Suc-β-CD nanohydrogels loading lapatinib and ginsenoside Rg1 showed the best results.

Growing impact of sialic acid-containing glycans in future drug discovery

In nature, almost all cells are covered with a complex array of glycan chain namely sialic acids or nuraminic acids, a negatively charged nine carbon sugars which is considered for their great therapeutic importance since long back. Owing to its presence at the terminal end of lipid bilayer (commonly known as terminal sugars), the well-defined sialosides or sialoconjugates have served pivotal role on the cell surfaces and thus, the sialic acid-containing glycans can modulate and mediate a number of imperative cellular interactions. Understanding of the sialo-protein interaction and their roles in vertebrates in regard of normal physiology, pathological variance, and evolution has indeed a noteworthy journey in medicine. In this tutorial review, we present a concise overview about the structure, linkages in chemical diversity, biological significance followed by chemical and enzymatic modification/synthesis of sialic acid containing glycans. A more focus is attempted about the recent advances, opportunity, and more over growing impact of sialosides and sialoconjugates in future drug discovery and development.

Cu(I)-Catalyzed Click Chemistry in Glycoscience and Their Diverse Applications

Copper(I)-catalyzed 1,3-dipolar cycloaddition between organic azides and terminal alkynes, commonly known as CuAAC or click chemistry, has been identified as one of the most successful, versatile, reliable, and modular strategies for the rapid and regioselective construction of 1,4-disubstituted 1,2,3-triazoles as diversely functionalized molecules. Carbohydrates, an integral part of living cells, have several fascinating features, including their structural diversity, biocompatibility, bioavailability, hydrophilicity, and superior ADME properties with minimal toxicity, which support increased demand to explore them as versatile scaffolds for easy access to diverse glycohybrids and well-defined glycoconjugates for complete chemical, biochemical, and pharmacological investigations. This review highlights the successful development of CuAAC or click chemistry in emerging areas of glycoscience, including the synthesis of triazole appended carbohydrate-containing molecular architectures (mainly glycohybrids, glycoconjugates, glycopolymers, glycopeptides, glycoproteins, glycolipids, glycoclusters, and glycodendrimers through regioselective triazole forming modular and bio-orthogonal coupling protocols). It discusses the widespread applications of these glycoproducts as enzyme inhibitors in drug discovery and development, sensing, gelation, chelation, glycosylation, and catalysis. This review also covers the impact of click chemistry and provides future perspectives on its role in various emerging disciplines of science and technology.

An Efficient Microwave-Mediated Synthesis of Hexavalent Sialic Acid Sulfoglycodendrimers as Potential Anti-HIV Agents

A series of four sialic acid-containing hexavalent sulfoglycodendrimers (SGDs) were synthesized in excellent yields using an efficient strategy involving multiple microwave-mediated reactions. Four sugars, sialic acid, and the dimer through tetramer of α-2→8-linked oligosialic acid were added to an aminooxy-terminated hexavalent dendrimer core using a chemoselective oxime-forming reaction. This method resulted in substantial improvements in reaction time and product yields over previous methods. These multivalent glycopolymers were designed as potential topical agents for preventing the sexual transmission of HIV-1. While inactive against HIV-1, the SGDs were also not cytotoxic, opening a pathway for the further development of anti-HIV SGDs.