One-pot synthesis of glycyrrhetic acid polyglycosides based on grafting-from method using cyclic sulfite

ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016

This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Thermoresponsive Structure and Dye Encapsulation of Micelles Comprising Bolaamphiphilic Quercetin Polyglycoside

A bolaamphiphile is a special member of amphiphilic molecules, which contains a hydrophobic skeleton and two water-soluble groups on both ends. Bolaamphiphiles form thermally stable associates in water under lower concentration than those of typical monoheaded amphiphiles, indicating the potential usefulness of bolaamphiphiles as the component of nanomaterials. However, the structural diversity of bolaamphiphiles is limited at this moment. We recently developed the synthesis of quercetin-3-O-polyglycoside (QP) as a new entry of bolaamphiphiles via a one-pot polymerization using sugar-based cyclic sulfite initiated by quercetin skeleton. Herein, we show the bolaamphiphilic properties of QP in detail. The micellization behaviors of QP are systematically investigated through comparison with those of quercetin (Que) and isoquercitrin (IQ) to evaluate the roles of glycone on the micellization of quercetin derivatives. The morphology of the micelles bearing QP is observed by cryo-transmission electron microscopy (cryo-TEM), suggesting the formation of bolaamphiphile-specific giant ribbon-like micelles in addition to spherical micelles. The thermoresponsive micellization behaviors are also discussed through the critical micelle concentration (CMC) values, the dynamic light scattering analyses at various temperatures, and thermal hysteresis of the micellizations. It is indicated that the polysaccharide chains integrated on the surface of micelles would serve as a steric protecting group to endow the micelles with kinetic stability. These results will shed light on natural glycoside skeletons to design a new class of micelles for advanced health applications in near future.

Substituent Optimization of (1 → 2)-Glucopyranan for Tough, Strong, and Highly Stretchable Film with Dynamic Interchain Interactions

Polysaccharide is a naturally abundant material, which is regarded as an indispensable scaffold for a structural material. The properties of polysaccharides are dependent not only on the structure of repeating sugar unit but also the glycosidic position between the repeating units. Herein, we report the development of polysaccharide-based self-standing film consisting of naturally occurring (1 → 2)-glucopyranan skeleton. The self-standing film of (1 → 2)-glucopyranan derivative with hexyl carbamate groups Uret-Glcp(1,2) is found to be highly stretchable and tough, which exhibits maximum stress of σ_max = 1.4 MPa, fracture strain of ε ∼ 800%, and the work of extension at fracture W_ext ∼ 4 MJ m^-3. It is indicated that the interchain hydrogen bonds in Uret-Glcp(1,2) film would serve as energy dissipative bonds for strengthening the film, where the application of mechanical stress to Uret-Glcp(1,2) film induces not only the rapture of physical interchain interactions, but also the formation of intrachain hydrogen bonds along the stretching direction. The effects of substituent and glycosidic position of polysaccharide on the properties are discussed in detail.

Bolaamphiphilic properties and pH-dependent micellization of quercetin polyglycoside

Quercetin polyglycoside as a new bolaamphiphile is prepared via a one-pot grafting polymerization technique using sugar-based cyclic sulfite. Micelles comprising quercetin polyglycoside exhibit special pH-effects, in which the polyglycoside moieties on the surface of the micelle serve as a steric protecting group to endow chemical stabilization.

Structural factors of benzylated glucopyranans for shear-induced adhesion

We have prepared benzylated glucopyranans and evaluated the structural effects on the adhesion capacity. It was found that 97%-benzylated (1→2)-glucopyranan exhibited a unique shear-induced adhesion. The effects of structural factors on the adhesion behaviors are discussed through systematic adhesion tests, differential scanning calorimetry, theoretical models, and IR spectroscopy.

Shear-induced adhesion of benzylated (1→2)-glucopyranan is attributed to the kinetically stabilized elongated structure and the switchable projection of hydroxyl groups induced by stress.