Unusual photophysical properties of polyphenol film

A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 117912 Moscow. Institute of Physical Organic Chemistry, Academy of Sciences of Belarus, 220603 Minsk. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1691–1692, July, 1992.     

槟榔提取物中多酚含量的测定

考察了福林酚试液用量、Na_2CO_3溶液用量、反应时间等因素对槟榔提取物中多酚测定的影响,确定了多酚测定条件,建立了测定槟榔提取物中多酚的方法.结果表明,在选定的测定条件下,没食子酸浓度在2.0～10.0 mg/L之间与吸光度成良好线性关系.线性方程为:y=0.103 8x-0.067 6;相关系数r=0.999 5;检测限为0.026 mg/L.该方法具有仪器简单、操作简便,准确度高等特点,用于槟榔提取物中多酚的测定,结果满意.     

Enzymic oxidation of dopamine by polyphenol oxidaze

The kinetics of the enzymic oxidation of dopamine (A) by polyphenol oxidaze (E) was studied by spectrophotometrically monitoring the concentration of the reaction product, 2,3-dihydroindole-5, 6 quinone, at 470 nm. The kinetics model proposed for the reaction and the effect of pH agreed with the experimental data and the resulting rate equation is given by where [A] is the concentration of dopamine (mM), [E_o] the concentration of polyphenol oxidaze (mg/1) and [H⁺] the concentration of hydrogen ion (M) in the reaction mixture. © John Wiley & Sons, Inc.     

Soluble carbon nanotubes

Carbon nanotubes have attracted great interdisciplinary interest because of their unique structure and properties. However, carbon-nanotube research is challenged by several problems, such as: i) mass production of material, ii) control of length, diameter, and chirality, and iii) manipulation for use in diverse technological fields. Issues regarding the synthesis and purification as well as the functionalization and solubilization of carbon nanotubes are relevant topics in this rapidly growing field. In this paper, covalent and noncovalent approaches to functionalized and solubilized nanotubes are examined in detail, with particular emphasis on the change of properties that accompany the chemical modification.     

Tebrophen--an old polyphenol drug with anticancer potential

In vitro high-throughput screening was carried out in order to detect new activities for old drugs and to select compounds for the drug development process comprising new indications. Tebrophen, a known antiviral drug, was found to inhibit activities on inflammation and cancer related targets. In primary screening this semisynthetic halogenated polyphenol was identified to inhibit the activities of kinases ZAP-70 and Lck (IC?? 0.34 μM and 16 μM, respectively), as well as hydrolase DPPIV (at 80 μM 41% inhibition). Next, it showed no cytotoxic effects on standard cell lines within 24 h. However, tebrophen slowed propagation of breast cancer (MDA-MB-231), osteosarcoma (U2OS) and cervical carcinoma (HeLa), through at least 35 population doublings in a dose-dependent manner. It completely stopped the division of the prostate cancer (PC3) cell line at 50 μM concentration and the cells entered massive cell death in less than 20 days. On the other hand, tebrophen did not influence the growth of normal fibroblasts. According to the measured oxidative burst and estimated in silico parameters its direct antioxidative ability is limited. The obtained results indicate that tebrophen can be considered a promising lead molecule for generating more soluble derivatives with specific anticancer efficacy.     

Chromatographic and electrophoretic methods for determining polyphenol compounds

The main physicochemical methods for identifying and quantifying polyphenol compounds in various plant and food objects (tea, wine) and human biological fluids (urine, plasma, blood serum, saliva) were reviewed, such as chromatography (high-performance liquid chromatography and thin-layer chromatography) and electrophoresis (capillary zone electrophoresis and micellar electrokinetic chromatography). Different procedures for sample preparation were discussed, including liquid, solid-phase, supercritical fluid extraction, and high-pressure liquid extraction.     

A new crosslinkable polyphenol from a renewable resource

Cardanol, a major component obtained by thermal treatment of cashew nut shell liquid, is a phenol derivative mainly having a C15 unsaturated hydrocarbon chain with 1–3 double bonds at the m‐position. We polymerized cardanol using an Fe‐salen complex as the catalyst to give a soluble polyphenol containing the unsaturated alkyl group in the side chain. The polymer was subjected to hardening by a cobalt naphthenate catalyst or thermal treatment, yielding crosslinked film with high gloss surface.     

New Soluble Fluorinated Polyimides

Aromatic polyimides have been widely used in aerospace, electrical and electronic applications due to their outstanding thermal stability, mechanical strength at elevated temperature and electrical properties1-3. However, polyimide materials are usually difficulty to fabricate owing to their insolubility in most organic solvents and infusibility. Besides solubility, low moisture uptake of polyimide is also a major concern for microelectronics and optical applications. The present article descr…     

可溶性高分子负载催化剂

均相催化剂的负载化是解决催化剂分离与回收的一条有效途径,也是绿色化学研究的重要内容。可溶性高分子,尤其是树状大分子作为另一类催化剂载体近年来受到了越来越多的关注。通过选择合适的反应介质,可溶性高分子负载催化剂可以在均相条件下催化有机反应,反应结束后通过外加不良溶剂的固/液相分离、温度等调控的液/液相分离以及膜过滤等方法进行催化剂的分离与回收。本文概述了在可溶性高分子负载催化剂研究中取得的新进展,重点介绍了负载手性催化剂在不对称催化反应中的应用。     

Soluble and immobilized catalase

This article examines the effect of pressure on the steady-state kinetics and long-term deactivation of the enzyme catalase supported on porous alumina. The reaction studied is the decomposition of hydrogen peroxide. The results of studies carried out in a continuous stirred-tank reactor under isothermal conditions are presented and compared with results obtained for soluble catalase. For soluble catalase, it is found that in the range of pressures studied, the oxygen flow rate increases with increase in pressure up to a certain value and then decreases. Hydrogen peroxide concentration appears to have a strong influence on pressure effects. With immobilized catalase, the pressure effects are not as prominent. Fluorescent microscopy studies of the immobilized enzyme suggest that this is probably because of pore diffusional limitations.     

Chemiluminescence change of polyphenol dendrimers with different core molecules

Second generation polyphenol dendrimers (PDs) with different core molecules were synthesized, and their chemiluminescence (CL) was measured by reacting the PDs with H2O2 under alkaline conditions. All of the PDs showed a strong CL, more than 120-fold greater than that of gallic acid. Various CL intensities of the PDs were obtained using different core molecules in the PDs. The distance between each dendron in the PD structure is crucial in the PD CL intensity.     

可溶性聚合物支载的试剂和催化剂

本文总结了近15年来液相化学领域内出现的可溶性聚合物支载的各类试剂和催化剂及其应用。     

Synthesis of Soluble Fluorene-polyimino Ketone

Based on the 9,9-di(4-anilinyl)fluorene, structurally different fluorene-polyimino ketones have been obtained by the Buchwald-Hartwig cross coupling reaction. Their structure and performance have been characterized by FT-IR, 1H NMR, UV-vis and thermal analysis. The results show an agreement with the proposed structure, which possesses high glass transition temperature (Tg＞250 ℃) and good thermal stability with high decomposition temperatures in nitrogen atmosphere (TD＞520 ℃). Additionally, the polymers synthesized showed good solubility, which can be dissolved in common organic solvent CHCl3 at room temperature.     

Soluble polysaccharides of Rhodotorula flava

Conclusions 1. Xanthalin has been shown to have the structure of 2, 2-dimethyl-3, 4,-diangeloyloxy-3, 4-dihydropyrano-5, 6:6, 7-coumarin on the basis of the preparation of a number of derivatives and cleavage products.2. The following products of the alkaline hydrolysis of xanthalin have been isolated and characterized for the first time: (±)-3, 4-dihydroxy-3, 4-dihydroxanthyletin (isokhellactone), C₁₄H₁₄O₅, with mp 213–215° C and (–)-trans-3-hydroxy-4-methoxy-3, 4-dihydroxanthyletin (isomethylkhellactone, C₁₅H₁₆O₅, with mp 136.5–138° C and [] _D ²⁰ –47.7 (ethanol).Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 14–19, 1970     

水溶性酞菁化合物的合成

酞菁化合物即四氮杂四苯骄卟啉,是一类光氧化还原反应的有效敏化剂以及重要的有机半导体和光导体材料。近年来,发现酞菁对恶性肿瘤具有荧光定位诊断和光动力治疗作用,并对金黄色葡萄球菌、链球菌和某些寄生虫具有光灭活作用,正引起人们的日益关注。目前已报道的水溶性酞菁大多系不纯化合物,