Tulika Malviya

Microwave promoted methylation of plant polysaccharides

Abstract O -Methylation is of outstanding importance in structural polysaccharide chemistry. A novel method for the methylation of polysaccharides using microwave (MW) irradiation is described. Seed gum from Cyamopsis tetragonolobus (Guar) was fully methylated with dimethyl sulphate and sodium hydroxide using 100% microwave power for 4 min in 68% yield. The completely methylated seed gum thus obtained was hydrolyzed by 70% formic acid followed by 0.5N H 2 SO 4 under full microwave power for 1.16 and 1.66 min, respectively. The partially methylated monosaccharides were separated and identified.

Polysaccharide-Silica Hybrids: Design and Applications

This article discusses and reviews the current status and future perspectives of silica hybrids of polysaccharides and biosilicas derived thereof. The hybrids have been produced in various morphological shapes and utilized in water remediation, separation, enzyme immobilization, sensor, and biomedical fields. The polysaccharides show templating and structure directing influence in manipulation of sol gel silica hybrid materials which can be calcined to derive functional biosilicas. The development of energy storage devices and white light emitting solid phosphors may be the fields of future research.

Grafting of vinyl acetate-ethylacrylate binary monomer mixture onto guar gum.

Present article reports on guar gum (GG) functionalization through graftcopolymerization of vinylacetate (VAC) and ethylacrylate (EA) from their binary mixtures. The potassium persulfate/ascorbic acid (KPS/AA) redox initiator system has been used for the binary grafting under the previously optimized conditions for VAC grafting at guar gum. The concentration of ascorbic acid (AA), persulfate (KPS), and grafting temperature were varied to optimize the binary grafting. A preliminary investigation revealed that the copolymer has excellent ability to capture Hg(II) from aqueous solution. It was observed that the optimum % grafting sample (CP3) was best at Hg(II) adsorption. CP3 and mercury loaded CP3 (CP3-Hg) have been extensively characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Thermo gravimetric analysis (TGA) and a plausible mechanism for the grafting has been proposed.

Synthesis of Aloevera/Acrylonitrile based Nanoparticles for targeted drug delivery of 5-Aminosalicylic acid

Aloevera (AV) polysaccharide/acrylonitrile (AN) nanoparticles (AVANp4 of ∼50nm size) have been crafted via free radical polymerization method using persulfate/ascorbic acid (KPS/AA) and methylenebisacrylamide (MBA) as the redox initiator and crosslinker respectively. AVANp4 was extensively characterized using FTIR, SEM, TEM, XRD, and Thermal analysis (TGA & DTG). Inclusion of AN in AV polysaccharide has been evidenced by nitrile stretching peak at 2244cm-1 in FTIR spectrum of AVANp4. Colon specific targeted in-vitro release of 5-Aminosalicylic acid from AVANp4 has been studied in pH 1.2 and pH 7.4 buffer solutions at 37°C. The controlled release was witnessed up to 48h for AVANp4 in contrast to AV for which the release exhausted within 7-8h in both the buffers. The delayed release of the drug from AVANp4 is attractive since it can allow the drug to reach colon rather than being released in the upper part of the gastrointestinal tract.

Gum acacia–CuNp–silica hybrid: an effective, stable and recyclable catalyst for reduction of nitroarenes

A gum acacia–CuNp–silica hybrid behaved as an efficient catalyst for the sodium borohydride reduction of nitroarenes. The hybrid (3 × 10−3 g) in combination with 0.1 M NaBH4 was capable of reducing 4-nitrophenol into 4-amino phenol within 2.3 minutes at room temperature. The reduction did not require any exclusion of oxygen or moisture. The catalyst retained its full activity even after one month storage under the laboratory conditions. It could be easily recycled for six repeated cycles with only marginal loss of catalytic activity. The conditions for borohydride reduction of 4-nitrophenol have been optimized, and under these conditions the reduction of 4-nitroaniline and 4-nitrobenzoic acid was possible within 3.15 and 8.3 minutes, respectively.

Polysaccharide-Based Macromolecular Materials for Decolorization of Textile Effluents

Polysaccharides are the renewable natural reservoir which can be tailored to obtain a broad spectrum of macromolecular materials. The multifunctional nature of polysaccharides offers wide flexibility of tailoring and modification. To suit adsorption applications, many water-soluble polysaccharides have been transformed to insoluble materials by chemical modification and cross-linking. These materials have also been utilized for coagulation–flocculation of industrial wastes. Depending upon the targeted application, which may be either adsorption or coagulation and flocculation, the solubility and characteristics of these materials are tailored. Present chapter focuses on the polysaccharides and polysaccharide-derived materials that are known to decolorize industrial waste and synthetic aqueous dye solutions through flocculation and adsorption.

Carboxymethyl cellulose-rosin gum hybrid nanoparticles: An efficient drug carrier

Adequate release of 5-ASA in colon is challenging as it easily permeates at the acidic pH of the upper gastrointestinal tract. Targeting delayed release of 5-ASA at acidic pH, Carboxymethyl cellulose-rosin gum hybrid nanoparticles (CRNP3) with an average size of 267nm have been crafted through nanoprecipitation method. CRNP3 was extensively characterized using Fourier Transform Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and particle size analysis based on dynamic light scattering. Colon specific targeted in-vitro release of 5‑Aminosalicylic acid from CRNPs was monitored in simulated gastric (SGF) and intestinal (SIF) fluids. The release rate was very slow in first 2h in SGF, while in SIF, it was greater and 72% drug was released in a controlled manner during the time span of 12h in contrast to native carboxymethyl cellulose or rosin gum for which 100% release was accomplished within 5h or 8h respectively. The delayed release from CRNPs is attractive for enhancing the bioavailability of drug in colon. The drug release followed zero-order kinetics and non-Fickian diffusion mechanism.