红托竹荪多糖抗氧化活性的研究

本文采用DPPH自由基、羟自由基及超氧阴离子自由基体系对红托竹荪多糖的抗氧化活性进行了研究,并同Vc和BHT进行了比较.结果表明,在0.2～1.2 mg/mL质量浓度范围内,红托竹荪多糖对DPPH自由基、羟自由基、超氧阴离子自由基的半数清除率(EC50)值分别为1.468、2.580和2.330,抗氧化活性稍强于BHT,但弱于VC.     

国槐叶黄酮的抗氧化活性研究

本文采用ABTS清除体系、DPPH清除体系、H2O2/Fe2+/水杨酸检测体系、亚硝基清除体系、普鲁士蓝法、邻苯三酚自氧化法研究了国槐叶黄酮的抗氧化活性,并同芦丁、Vc进行了比较。结果表明,国槐叶黄酮对几种自由基均有不同的清除效果,在质量浓度为50μg/mL时,国槐叶黄酮对羟基自由基(·OH)、ABTS、DPPH、亚硝基自由基(NO2-)和超氧阴离子自由基(O2-·)的清除率为分别62.09%、47.70%、43.28%、22.11%、21.83%;与芦丁、Vc相比较,国槐叶黄酮清除ABTS、DPPH自由基的能力低于芦丁和Vc,而清除NO2-、.OH的能力高于芦丁和Vc,对O2-·的清除能力低于Vc而高于芦丁,其次国槐叶黄酮具有很好的还原力。由此说明,国槐叶提取物可以作为天然抗氧化剂,可以应用在医药食品领域。     

小叶锦鸡儿花提取物和不同极性黄酮组分的抗氧化活性(英文)

测定了小叶锦鸡儿(Caragana microphylla Lam.)花粗提物和不同极性组分总黄酮含量和各项抗氧化能力指标。结果表明:小叶锦鸡儿花不同极性的黄酮组分的抗氧化活性有明显差别,其总抗氧化能力与溶剂极性之间有显著正相关性(P<0.05),但其它抗氧化活性与溶剂极性之间均无显著相关性(P>0.05)。同一极性黄酮组分在不同抗氧化体系中的抗氧化活性有较大差别。对DPPH.自由基的清除能力最强的为乙酸乙酯层(EC50=0.11 mg/mL),其次是二氯甲烷层(EC50=0.38 mg/mL)和乙醇粗提物(EC50=0.56 mg/mL)。总抗氧化能力(T-AOC)最强的为水层,在1 mg/mL时为1.482个T-AOC能力单位。清除羟自由基.OH能力最强的为水层,其次为正己烷层和乙醇粗提物,在3.57 mg/mL时清除率分别为86.23%、66.04%和64.63%。清除超氧阴离子自由基O2-.能力最强的为水层,其次为乙醇粗提物,在1 mg/mL时其清除率分别相当于0.15 mg/mL Vc清除率的336.17%和318.20%。可见,小叶锦鸡儿花的粗提物和不同极性黄酮组分具有较好的抗氧化活性,可用于提取、制备抗氧化特性和作用不同的天然抗氧化剂。     

响应面法优化芦荟中抗氧化活性成分的提取工艺

对芦荟中抗氧化活性物质提取工艺及其成分进行研究,通过单因素实验和响应面优化,以提取物对DPPH自由基的清除率为抗氧化的考察指标,得到芦荟中抗氧化活性成分的提取工艺条件:提取温度29 ℃、料液比(g/mL)1:33、提取时间107 s、微波功率500 W,微波辅助水提,此条件下得到的提取物对DPPH自由基的清除率达91.414%.提取物活性成分分析表明:提取物中芦荟甙含量为1.5 mg/g、黄酮为1.13 mg/g、多酚为4.33 mg/g、多糖为126.36 mg/g.     

4种竹叶营养成分分析及其黄酮提取物体外抗氧化活性研究

为探究4种竹叶的营养成分、黄酮含量以及竹叶黄酮提取物的抗氧化活性。以观音竹、金竹、紫竹和孖竹等4种竹为研究对象,分析了竹叶中的主要营养成分及黄酮含量,并提取获得了4种竹叶的黄酮提取物,以DPPH、ABTS自由基清除率以及亚铁还原力和金属螯合能力等指标评价竹叶黄酮提取物的抗氧化能力。结果表明,粗蛋白孖竹最高,观音竹最低,粗脂肪观音竹最高,孖竹最低,粗纤维观音竹最高,孖竹最低,钙金竹最高,观音竹最低,黄酮观音竹最高,金竹最低;体外抗氧化活性结果表明,金竹黄酮提取物清除DPPH自由基的效果最好,观音竹黄酮提取物清除DPPH自由基的效果与BHT接近,对ABTS自由基的清除能力大小顺序为BHT孖竹金竹紫竹观音竹,4种竹叶黄酮提取物的亚铁还原能力均强于BHT,而金属螯合能力明显低于EDTA;竹叶中黄酮含量与ABTS自由基清除显著的正相关性,与DPPH自由基清除和亚铁还原能力无显著相关性。表明金竹黄酮提取物和孖竹黄酮提取物在体外具有较强的抗氧化性。     

响应面法优化豫西山茱萸叶黄酮的提取及其抑菌和抗氧化活性

通过响应面法对山茱萸叶黄酮的提取工艺进行优化,并对其体外抑菌和抗氧化活性进行研究。经优化后,山茱萸叶黄酮在超声功率290 W、液料比31∶1(mL/g)、乙醇体积分数61%、提取时间23 min的工艺条件下提取得率最高,达到6.31%,与模型预测值相符。抑菌实验结果表明山茱萸叶黄酮对沙门氏菌有较强的抑菌作用,对绿脓杆菌、金黄色葡萄球菌和中华根霉有较弱的抑菌作用,说明山茱萸叶黄酮对细菌有较强的抑菌作用,对真菌有较弱的抑菌作用。山茱萸叶黄酮浓度为1.2 mg/mL时其对DPPH自由基的清除率为77.24%,对羟基自由基的清除率达到83.54%;山茱萸叶黄酮清除DPPH自由基和羟基自由基的IC_(50)分别为0.699和0.631 mg/L,表明山茱萸叶黄酮具有较强的抗氧化活性。     

不同分子量菊芋多糖的生物活性研究

研究不同醇沉组份的菊芋多糖分子量和其抑制α-葡萄糖苷酶活性与抗氧化活性差异。菊芋水提物分级醇沉获得粗多糖,过Sephadex G-50凝胶柱进行纯化,得到重均分子量为1959、2180、2746、2011 Da的多糖组分:JAP-1、JAP-2、JAP-3和JAP-4。测定这些组分体外抑制α-葡萄糖苷酶活性和对DPPH与羟基自由基清除能力。结果表明,JAP-4具有较明显的抑制α-葡萄糖苷酶活性,在5 mg/mL时抑制率为20.32%。JAP-1、JAP-2、JAP-3和JAP-4均有显著的抗氧化活性,其中JAP-2对DPPH自由基和羟基自由基的清除活性优于其他组分。JAP-2在2 mg/mL时对DPPH自由基和羟基自由基清除率分别达到84.50%和89.74%,接近于Vc的抗氧化活性。不同分子量菊芋多糖的活性存在差异,可能是由于分子量的不同所导致。     

蓬莪术根茎总黄酮的提取及体外抗氧化分析

为了合理地开发和利用蓬莪术的药用价值,通过响应面法对蓬莪术根茎总黄酮超声波辅助提取进行工艺优化,并探究粗制黄酮和纯化黄酮的还原力和对DPPH、羟基自由基、超氧阴离子的清除能力。结果表明,在超声功率300 W的条件下,以乙醇浓度80%、液料比40 mL/g、超声时间50 min、超声温度70℃的提取效果最佳,总黄酮得率为1.593%。在体外抗氧化活性分析中,蓬莪术根茎粗制黄酮对DPPH、羟基自由基、超氧阴离子及还原力的IC_(50)值分别为1.255 mg/mL、0.597 mg/mL、1.041 mg/mL和3.508 mg/mL,而纯化黄酮的IC50值分别为0.333 mg/mL、0.076 mg/mL、0.084 mg/mL和1.477 mg/mL。因此,响应面可以很好的对蓬莪术根茎总黄酮超声辅助提取进行优化,且粗制黄酮和纯化黄酮都具有良好的抗氧化活性。     

乌奴龙胆乙醇提取物不同极性部位体外抗氧化性研究

本文以BHT和VC为对照,采用分光光度法,通过四种不同体系对乌奴龙胆乙醇提取物的各个极性部位体外抗氧化活性进行比较研究。结果表明,各极性部位对DPPH自由基、羟基自由基和超氧阴离子自由基均有一定的清除作用,也具有一定的还原能力。其中氯仿部位、乙酸乙酯部位效果最佳,其总还原力和对DPPH自由基的清除作用均优于BHT,本实验结果为扩展乌奴龙胆的应用范围和进一步研究其抗氧化活性成分及新型天然抗氧化剂的开发提供了理论依据。     

高分子量褐藻多酚抗氧化性质研究

采用DPPH体系、羟基自由基体系、烷基自由基引发的亚油酸氧化体系、超氧阴离子自由基体系对海黍子高分子量褐藻多酚抗氧化性质进行了研究,发现其清除DPPH活性、清除羟基自由基活性、抑制烷基自由基引发的亚油酸氧化的活性分别为77％、27％和21％,但它不具有清除超氧阴离子自由基的能力。褐藻多酚具有供氢能力,其连三羟基的供氢能力大于间三羟基,清除羟基自由基与其苯环提供的羟基自由基加成位点的数量有关。     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV     

Similar aerosol emission rates and viral loads in upper respiratory tracts for COVID-19 patients with Delta and Omicron variant infection

Highlights
1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference.     

Recombinant human interferon-α1b inhibits SARS-CoV-2 better than interferon-α2b in vitro

Highlights
1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID₅₀ method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC₅₀=0.12 IU/mL in Vero cells and EC₅₀=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC₅₀=0.25 IU/mL in Vero cells and EC₅₀=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy.     

Continued antigenic variation of highly pathogenic avian influenza A (H7N9) virus in laying hens in China, 2020–2021

Highlights
1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection.