Starch functionalized creatine for stabilization of gold nanoparticles: Efficient heterogeneous catalyst for the reduction of nitroarenes

Spectrophotometric and chromatographic analysis of creatine:creatinine crystals in urine

Creatinine is the end product of the catabolism of creatine and creatine phosphate. Creatine phosphate serves as a reservoir of high-energy phosphate, especially in skeletal and cardiac muscle. Besides typical known changes in serum and urinary creatinine concentrations, rare cases associated with changes in serum and urinary creatine levels have been described in the literature in humans. These cases are mostly linked to an excessive intake of creatine ethyl ester or creatine monohydrate, often resulting in increased urine creatinine concentrations. In addition, it is known that at such elevated creatinine concentrations, creatinine crystallisation may occur in the urine. Analysis of crystals and urinary concrements, often of heterogenous chemical composition, may provide diagnostic and therapeutic hints to the benefit of the patient. The aim of the present work was to analyze urine crystals of unclear composition with microscopic and spectroscopic techniques. On routine microscopic analysis of urine, a preliminary suspicion of uric acid or creatinine crystals was expressed. The crystals were of a cuboid shape and showed polarization effects in microscopy. The dried urine sample was whitish-orange in colour, odourless and dissolved well in water. Protein concentration in dry weight (DW) urine was about 0.3 mg/mg. The measured zinc content in the studied sample was approximately 660 µg/g DW sample and copper content was approximately 64 µg/g DW sample. A lead signal of around 10 µg/g DW sample was also observed. UV-Vis analysis showed a maximum creatine peak around 220 nm, compatible with the spectrum of creatinine with a maximum peak of 230 nm. Using HPLC technique, an extreme high ratio of creatine to creatinine of about 38 was measured, which led to the conclusion of the occurrence of rare creatine crystals in urine.

How the Chemical Properties of Polysaccharides Make It Possible to Design Various Types of Organic-Inorganic Composites for Catalytic Applications

Recently, the use of plant-origin materials has become especially important due to the aggravation of environmental problems and the shortage and high cost of synthetic materials. One of the potential candidates among natural organic compounds is polysaccharides, characterized by a number of advantages over synthetic polymers. In recent years, natural polysaccharides have been used to design composite catalysts for various organic syntheses. This review is devoted to the current state of application of polysaccharides (chitosan, starch, pectin, cellulose, and hydroxyethylcellulose) and composites based on their catalysis. The article is divided into four main sections based on the type of polysaccharide: (1) chitosan-based nanocomposites; (2) pectin-based nanocomposites; (3) cellulose (hydroxyethylcellulose)-based nanocomposites; and (4) starch-based nanocomposites. Each section describes and summarizes recent studies on the preparation and application of polysaccharide-containing composites in various chemical transformations. It is shown that by modifying polysaccharides, polymers with special properties can be obtained, thus expanding the range of biocomposites for catalytic applications.

The untold story of starch as a catalyst for organic reactions

Starch is one of the members of the polysaccharide family. This biopolymer has shown many potential applications in different fields such as catalytic reactions, water treatment, packaging, and food industries. In recent years, using starch as a catalyst has attracted much attention. From a catalytic point of view, starch can be used in organic chemistry reactions as a catalyst or catalyst support. Reports show that as a catalyst, simple starch can promote many heterocyclic compound reactions. On the other hand, functionalized starch is not only capable of advancing the synthesis of heterocycles but also is a good candidate catalyst for other reactions including oxidation and coupling reactions. This review tries to provide a fair survey of published organic reactions which include using starch as a catalyst or a part of the main catalyst. Therefore, the other types of starch applications are not the subject of this review.

Novel magnetic bimetallic AuCu catalyst for reduction of nitroarenes and degradation of organic dyes

Herein, core-shell magnetic nanoparticles are modified with imidazolium-tagged phosphine and propylene glycol moieties and used for the stabilization of bimetallic AuCu nanoparticles. The structure and morphology of the prepared material are identified with SEM, TEM, XRD, XPS, atomic absorption spectroscopy, Fourier translation infrared spectroscopy, and a vibrating sample magnetometer. This hydrophilic magnetic bimetallic catalyst is applied in the reduction of toxic nitroarenes and reductive degradation of hazardous organic dyes such as methyl orange (MO), methyl red (MR), and rhodamine B (RhB), as well as in the degradation of tetracycline (TC). This magnetic AuCu catalyst indicated superior activity in all three mentioned reactions in comparison with its single metal Au and Cu analogs. This catalyst is recycled for 17 consecutive runs in the reduction of 4-nitrophenol to 4-aminophenol without a significant decrease in catalytic activity and recycled catalyst is characterized.

In situ decorated Au NPs on chitosan-encapsulated Fe3O4-NH2 NPs as magnetic nanocomposite: Investigation of its anti-colon carcinoma, anti-gastric cancer and anti-pancreatic cancer

Chitosan is a linear polysaccharide and non-toxic bioactive polymer with a wide variety of applications due to its functional properties such as ease of modification, and biodegradability. In this investigation, magnetic cores (Fe₃O₄) were synthesized using a fabrication method involving coprecipitation of Fe²⁺ and Fe³⁺. Then the magnetic nanoparticles were encapsulated by chitosan layers. In the next step, magnetite-gold composite nanoparticles were synthesized with spherical shapes and sizes ranging from 20 to 30 nm, using sodium citrate as a natural reducing agent. The morphological and physicochemical features of the material were determined using several advanced techniques like FT-IR, ICP analysis, FESEM, EDS, XRD, TEM, XPS and VSM. In the biological part of the present study, the cell viability of Fe₃O₄, HAuCl₄, and Fe₃O₄@CS/AuNPs was very low against human colorectal carcinoma cell lines i.e. Ramos.2G6.4C10, HCT-8 [HRT-18], HCT 116, and HT-29, human gastric cancer cell lines i.e. MKN45, AGS, and KATO III, and human pancreatic cancer cell lines i.e. PANC-1, AsPC-1, and MIA PaCa-2. The IC50 of Fe₃O₄@CS/AuNPs against Ramos.2G6.4C10, HCT-8 [HRT-18], HCT 116, HT-29, MKN45, AGS, KATO III, PANC-1, AsPC-1, and MIA PaCa-2 cell lines were 385, 429, 264, 286, 442, 498, 561, 513, 528, and 425 μg/mL, respectively. Thereby, the best cytotoxicity results of our Fe₃O₄@CS/AuNPs were observed in the case of the HCT 116 cell line. Seemingly, the present nanoparticles may be used for the treatment of several types of gastro-duodenal cancers especially colon, gastric, and pancreatic cancers in near future.

In situ decorated Au NPs on pectin-modified Fe3O4 NPs as a novel magnetic nanocomposite (Fe3O4/Pectin/Au) for catalytic reduction of nitroarenes and investigation of its anti-human lung cancer activities

In recent days, the green synthesized nanomagnetic biocomposites have been evolved with tremendous potential as the future catalysts. This has encouraged us to design and synthesis of a novel Au NPs immobilized pectin modified magnetic nanoparticles (Fe₃O₄/Pectin/Au). It was meticulously characterized using advanced analytical techniques like FT-IR, FESEM, TEM, EDX, XPS, VSM, XRD and ICP-OES. We investigated the chemical applications of the material in the catalytic reduction of nitroarenes using N₂H₄.H₂O as the reducing agent in the EtOH/H₂O solvent without any promoters or ligands. Due to strong paramagnetism, the catalyst was easily recovered and reused in 11 cycles without considerable leaching or loss in reactivity. The green protocol involves several advantages like mild conditions, easy workup, high yields, and reusability of the catalyst. Furthermore, the desired nanocomposite was employed in biological studies like anti-oxidant assay by DPPH radical scavenging test. Subsequently, on exhibiting a good IC₅₀ value in the DPPH assay, we extended the bio-application of the Fe₃O₄/Pectin/Au in the anticancer study of adenocarcinoma cells of human lungs using three cancer cell lines, PC-14, LC-2/ad and HLC-1 and a normal cell line HUVEC. The best result was accomplished in PC-14 cell lines with the lowest IC₅₀ values.

Human hair catalyzed selective reduction of nitroarenes to amines

Nowadays, there is great demand to use natural, cheap, and biodegradable materials as catalysts in different organic reactions. In this work, we use human hair as a completely biodegradable, renewable, and available material for the reduction of nitroarenes in aqueous media at 50 °C. Using this new catalyst, structurally different aromatic nitro compounds, as well as heterocyclic compounds, are reduced to corresponding amines in high to excellent yields. The presented catalytic system is applicable for large-scale reduction of nitroarenes.