采用热水浸提法提取蓝莓果渣粗多糖,经DEAE-52 纤维素柱层析分级纯化.采用高效凝胶色谱、PMP柱前衍生化HPLC法、红外光谱和扫描电镜初步表征其结构特征,并通过清除自由基试验和抑制自由基引起的DNA氧化反应评价多糖体外抗氧化活性.结果显示分离纯化后得到BBP-0、BBP-1、BBP-2 和BBP-3 等 4 个主要组分;各组分平均分子量介于 3.75 ? 29.70 kDa;单糖组成试验结果表明 4 个组分均由甘露糖、半乳糖醛酸、半乳糖、葡萄糖、阿拉伯糖和鼠李糖组成,其占比各不相同;扫描电镜发现BBP-0 和BBP-1 结构较为致密,BBP-2 和BBP-3 较为疏松;抗氧化测试结果表明 4 个组分均具有一定的抗氧化能力且强弱顺序均为BBP-3＞BBP-2＞BBP-1＞BBP-0;BBP-3 对ABTS+·和DPPH·清除率达 92.13%和36.68%,抑制AAPH、GS·和·OH引起DNA氧化的TBARS百分数分别为 78.91%、70.41%和 85.21%.结论:从蓝莓果渣中分离纯化得到的 4 个多糖组分均具有抗氧化能力,其中以BBP-3 最强,研究结果可为抗氧化添加剂的开发提供参考.

本文采用Ce(OTf)3和Sc(OTf)3复合催化4-甲基-7-氨基苯并吡喃酮、芳香醛和二茂铁基乙炔发生Povarov三组分反应(Povarov-3CR),高效合成了 15种已知二茂铁基吡喃酮并喹啉化合物,产率为40.0％～66.8％;采用1H NMR、13C NMR和HR-MS(ESI)表征产物分子结构,通过抑制HO·和还原型谷胱甘肽自由基(GS·)引发DNA氧化反应测试比较化合物抗氧化活性,探究取代基种类、位置和数目对二茂铁基吡喃酮并喹啉抗氧化性能的影响.结果表明:抑制HO·引发DNA氧化反应测试显示,15个目标化合物相对空白硫代巴比妥酸活性物质吸光度百分数(TBARS百分数)为36.6％～83.3％;抑制GS·引发DNA氧化反应体系测试显示,15个目标化合物TBARS百分数达22.9％～67.2％;在分子中引入推电子基团(-N(CH3)2、-OCH3和-OH)均能提升目标化合物的抗氧化能力,而吸电子基团(-Cl)有降低抗氧化能力作用;二茂铁基吡喃酮并喹啉化合物的抗氧化性能优于二茂铁基喹啉化合物,是一类潜在的强抗氧化剂.

Mitochondria-targetable fluorescent chemosensors, Rhodamine-B and rhodamine 6G bearing syringaldehyde based receptors were designed and synthesized for efficient chemosensing of Zinc(II) ions. The probes showed the very selective naked eye color change to pink from colorless upon addition of Zinc(II) ions, further these probes showing turn-on fluorescence enhancement with Zn(II) ions by opening of rhodamine spirolactam. The probes are very sensitive towards Zn(II) ions among other ions. These probes RBS and R6S will be applicable to detect zinc ions upto the low level concentration 0.18 and 0.19 nano molar respectively. The affinity of these sensors RBS and R6S for Zinc (II) ions was found to be in the range of 1.12 x 10(4) M-1 and 7.28 x 10(4) M-1 respectively. 1H-nmr titrations of the probes with Zn(II) ions clearly indicating the spiroring opening of the spirolactam. DFT calculations supporting that the perceived photophysical changes of the probes on appendage of the zinc ions. Probes RBS and R6S are useable for selective staining mitochondria. Both of the probes are applicable to reveal labile Zn(II) in live Hela and MCF-7 cells via fluorescence imaging. RBS and R6S are also finding application on quantification of Zinc(II) ions inside mitochondria via fluorescence imaging.

[目的]对细辛多糖(Asarum polysaccharides,ASPs)进行分离纯化,考察其保润性并对热裂解产物进行分析.[方法]采用水提醇沉法得细辛粗多糖,经Sevag法脱蛋白后通过DEAE-52纤维素柱分离纯化.采用紫外(UV-vis)、傅里叶红外(FT-IR)、扫描电子显微镜(SEM)、热裂解-气质联用(Py-GC/MS)等方法研究了其结构、保润性、热裂解产物,并进行了卷烟评吸评价.[结果]细辛多糖经过纤维素柱分离纯化得到3个主要组分ASP1、ASP2和ASP3.3个组分与碘反应未变蓝表明其均为非淀粉.同时,经紫外、红外光谱扫描ASP1、ASP2和ASP3均为纯度较高多糖.扫描电镜(SEM)表明ASP1、ASP2和ASP3结构上均有较好的聚集性.在低湿和高湿环境下,3个组分的解湿、吸湿速率无明显差异,均能减缓烟丝含水率的变化.经300、600、900℃裂解,ASP1的热裂解产物共有44种,ASP2共有46种,ASP3共有47种,且3个组分均可以产生糠醛类、酮类、吡啶类等致香物质,如900℃时ASP1、ASP2和ASP3糠醛类含量分别为21.63％、21.01％、8.32％;酮类含量分别为9.88％、11.64％、21.77％.细辛多糖的卷烟评吸评价结果表明,细辛多糖对烟气的香气量、香气质和刺激性都有一定的改善,并以0.4和0.6 g·kg-1的添加量较为适宜.[结论]细辛多糖具有一定的保润性和防潮效果,在热裂解过程中可以产生对烟气有益的致香物质,同时将其添加至卷烟后,能提高卷烟烟气质量,改善抽吸品质,表明细辛多糖有可以作为烟草保润剂和增香剂的潜在应用价值.

采用水提醇沉法,以多糖提取率为响应指标,在单因素试验的基础上,经响应面优化试验确定蓝莓果渣多糖最佳提取工艺;通过脱蛋白、脱色和透析等操作后获得精多糖;采用抑制自由基引发的DNA氧化反应体系和淬灭自由基体系系统研究粗多糖和精多糖抗氧化能力.结果表明,最佳提取工艺为液料比59 mL/g、提取温度80℃、提取时间5.30 h,在此条件下多糖得率为2.33％.6个测试体系中,粗多糖和精多糖均能有效抑制自由基氧化DNA和淬灭自由基;多糖浓度为6 mg/mL时,在抑制AAPH、GS·和HO·引起的DNA氧化反应测试中,粗多糖的TBARS百分数分别为90.38％、87.48％和94.36％,精多糖分别为94.97％、91.41％和97.70％;粗多糖对ABTS·+、DPPH·和Galvinoxyl·清除率分别为68.85％、23.53％和13.39％,而精多糖分别为54.42％、16.87％和11.58％.

In this study, a series of Ni(5,10,15 and 20wt.%)/MgAl2O4 catalysts were prepared and used for the catalytic depolymerization of lignin under different solvents (water, ethanol, and methanol) and different reaction environment (N2, and H2). Highest bio-oil yield (81.8 wt.%) was found with 15wt.%Ni/MgAl2O4 catalyst in ethanol solvent under hydrogen environment at 280 °C for 30 min .reaction time. Moreover under hydrogen environment very less amount of unreacted residue was produced. Under this condition higher heating value 36.2 MJ/kg of bio-oil was obtained, which is significantly increases from 24.5 MJ/kg of lignin. Bio-oil analysis showed that in under nitrogen environment catalytic depolymerization of lignin produced alkyl phenolic monomer compounds 68.0% with methoxy phenolic compounds 24.0%. Interestingly hydrogen promoted the deoxygenating and hydrogenation reaction which produced higher cyclohexane compounds 38.2% and aromatic hydrocarbon 19%. GPC analysis showed that hydrogen enhanced the lower molecular weight compounds. Catalysts stability test showed excellent recyclability.

Phase and morphology controlled synthesis of nanomaterials have significantly tune the material's properties. Herein, we demonstrate the concentration of hydrochloric acid, which plays vital role to tune both crystallographic phase, and morphology of tungsten oxide. The high concentration of HCL (50 mu L, 37 M) favour in the formation of the monoclinic-WO3 hierarchical flower-like structures composed of nanoplates. On the other hand, hexagonal phase of WO3 nanorods were formed at lower concentration of HCl, respectively. Moreover, hydrogen evolution reaction (HER) was performed and hexagonal-WO3 nanorods was found to be highly active compared to monoclinic-WO3 and comparable with standard Pt/C. The best HER activity of hexagonal-WO3 nanorods was achieved due to its one-dimensional growth, larger surface area, and faster charge transfer. In addition, the electrocatalysts showed a negligible decrease in current density even after 10 h chronoamperometric (i-t) tests, suggesting high stability in acid media. (C) 2021 Published by Elsevier B.V.

在以水为溶剂、无催化剂条件下加热促使水杨醛类化合物与米氏酸发生反应,合成了18种香豆素-3-羧酸类化合物.利用1HNMR和13CNMR对合成产物结构进行了表征;并通过抑制HO?、还原型谷胱甘肽自由基(GS?)和2,2′-偶氮二异丁基脒二盐酸盐(AAPH)氧化DNA反应对其抗氧化活性进行检测,进而探究取代基种类和位置对香豆素-3-羧酸类化合物抗氧化性能的影响.结果表明:绿色高效地合成了目标化合物,产率为54.3％～95.6％;18种化合物均能够抑制HO?、GS?和AAPH氧化DNA,其相对空白组(DMSO)硫代巴比妥酸活性物质(TBARS)吸光度百分数(TBARS百分数)分别可达69.42％～93.39％、75.23％～99.45％和66.62％～97.72％;在抑制HO?、GS?和AAPH氧化DNA反应中,羟基取代化合物的TBARS百分数分别为69.42％～77.67％、75.23％～82.87％和66.62％～75.08％,远小于其他取代基的香豆素-3-羧酸类化合物,与水溶性维生素E的TBARS百分数相当,是一类潜在的抗氧化剂.

In order to find novel pyrazine- and thiazole-based derivatives with potent antioxidant properties, eight pyrazine-thiazole bi-heteroaryl compounds were designed and prepared via active group splicing method between pyrazine-Noxides and thiazoles. They were structurally characterized by H-1 NMR, C-13 NMR, IR, and HPLC-MS. Antioxidant abilities of the obtained compounds were evaluated by inhibiting radicals induced oxidation of DNA and quenching radicals. The results showed that eight compounds can effectively inhibit radicals induced oxidation of DNA and quench radicals, which revealed that the compounds have strong radical scavenging properties and reduction ability, and can be potential antioxidants. The effective measurement factor (n) values of these compounds ranged from 1.48 to 2.12 in 2,2-azobis(2-amidinopropanehydrochloride) (AAPH) induced oxidation of DNA. The absorbance percentages of eight compounds to the blank thiobarbituric acid reactive substance (TBARS percentage) were 54.3%similar to 76.1% and 55.4%similar to 68.3% in inhibiting HO center dot and glutathione radical (GS center dot) induced oxidation of DNA, respectively. Eight compounds can scavenge 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS center dot) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH center dot). In addition, it was found that the antioxidant activity of pyrazine-thiazole bi-heteroaryl compounds was significantly higher than that of pyrazine-oxazole bi-heteroaryl compound.