羧甲基槲皮素的体外抑菌活性研究

考察了槲皮素的水溶性衍生物3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠的体外抑菌活性。方法:用培养基将3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠进行倍比稀释,加入菌液至终浓度为107 cfu.mL-1,通过比浊法测定加药后细菌的生长情况。结果是3′-羧甲基槲皮素钠对金黄色葡萄球菌Staphylococcus aureus、金黄色葡萄球菌Wright、肺炎克雷伯菌、大肠杆菌、中间普氏菌的最小抑菌浓度分别为0.05,0.1,0.8 mg.mL-1,1.6,0.05 mg.mL-1;最小抑菌浓度下的抑菌率分别为98.8%,87.3%,83.9%,100.0%,100.0%。4′-羧甲基槲皮素钠对金黄色葡萄球菌、带荚膜的金黄色葡萄球菌、肺炎克雷伯菌、大肠杆菌、中间普氏菌的最小抑菌浓度分别为0.05,0.1,0.8,1.6,0.05 mg.mL-1;最小抑菌浓度下的抑菌率分别为92.4%,78.6%,87.5%,97.9%,99.8%。结论:3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠对革兰阳性菌、革兰阴性菌及厌氧菌均有良好的抑菌作用。     

柚子叶等5种中药对鸡粪中大肠杆菌的体外抑菌试验

目的:探讨柚子叶、狗肝菜、青蒿等中药对鸡源性大肠杆菌(Escherichia coli,E.coli)的体外抗菌效果。方法:运用糖发酵实验、甲基红实验、吲哚实验、溶血实验以及麦康凯培养基实验鉴定可疑菌;牛津杯法测定上述中药的抑菌直径;二倍稀释法测定上述中药的最低抑菌浓度和最低杀菌浓度。结果:上述五种中药对鸡大肠杆菌均有抑制作用,实验中抗菌效果最优的为柚子叶,其次为防风、牛蒡,青蒿、狗肝菜抑菌效果最差,最低抑菌浓度分别为62.5、125、125、250、250 mg/m L;最低杀菌浓度分别为125、250、250、500、500 mg/m L。结论:柚子叶对鸡源性大肠杆菌有一定抗菌作用。     

凤眼草抑菌活性成分的研究

对苦木科臭椿属植物臭椿的果实凤眼草(Ailanthus altissima)的95％乙醇提取液的抑菌活性进行了研究.利用系统溶剂萃取法得到了石油醚提取物、氯仿提取物、乙酸乙酯提取物和正丁醇提取物,重点研究了4种提取物对枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌的抑菌性和最低抑菌浓度.结果表明,乙酸乙酯提取物和正丁醇提取物均...     

抗菌防霉粉末涂料的研究

采用最低抑菌浓度法(MIC)选择抗菌剂，添加于粉末涂料中，研究了抗菌剂的最佳用量、抗菌防霉粉末涂料的抗菌性、涂膜性能、颜色的热稳定性及与其他粉末涂料的相容性。     

家蝇抗菌肽抑菌活性及其稳定性研究

通过体外抑菌实验,采用纸片扩散法对家蝇抗菌肽的抑菌性进行定性研究。试验用菌有金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白色念珠菌和黑曲霉菌。在对家蝇抗菌肽抗菌谱研究的基础上,进一步用肉汤稀释法（试管法）定量测定其最低抑菌浓度（MIC）,并对其稳定性进行研究。结果表明,家蝇抗菌肽对金黄色葡萄球菌、绿脓杆菌和大肠杆菌3种细菌有较好的抑制作用,而对白色念珠菌和黑曲霉没有明显的抑制作用,对金黄色葡萄球菌、绿脓杆菌和大肠杆菌最低抑菌浓度（MIC）分别为0.156 mg/mL、0.312 5 mg/mL和6.25 mg/mL。另外,对其稳定性进行讨论,结果表明,家蝇抗菌肽的稳定性良好。     

松香基氨基噻二唑衍生物的合成及抑菌活性研究

以松香或歧化松香为起始原料,通过提纯、Diels-Alder双烯加成和关环等反应合成了4个新型松香基氨基噻二唑衍生物化合物。通过红外、MS、1HNMR和元素分析对产物进行表征和确认。采用最低抑菌浓度法对目标产物的抑菌性能进行了测试,初步的结果显示化合物都有一定的抑菌活性,特别是化合物5-脱氢枞基-2-氨基-1,3,4-噻二唑对金黄色葡萄球菌和表皮葡萄球菌具有良好的活性,对其最低抑菌浓度均为4μg/mL。     

槲皮素衍生物抗癌活性研究新进展

槲皮素(Quercetin, QCT)具有广泛的药理作用和独特的生物活性,如抗癌、抗氧化、抗炎等。人们一直致力于对槲皮素支架进行修饰,以获得具有潜在抗癌活性的类似物,用于临床应用。概述了槲皮素衍生物的抗癌相关活动的最新进展。     

田基黄槲皮素提取液的抗氧化活性研究

在芝麻油中添加田基黄槲皮素提取液,考察紫外光、反应温度对芝麻油过氧化值的影响以及提取液的自由基清除能力。结果表明,分别用紫外灯照射6 h和60℃下加热10 h,添加田基黄槲皮素提取液的芝麻油,其过氧化值比添加BHT和未添加抗氧化剂低14.73%,25.53%和38.4%,70.3%;自由基清除能力实验表明,60℃时,槲皮素提取液的还原能力是BHT的1.88倍;50℃时的羟基自由基清除率、O2-.清除率和过氧化氢清除率分别是BHT的1.49,1.02倍和1.04倍。     

麻疯树籽毒蛋白抑菌活性初步研究

通过浸泡、匀浆、离心、干燥等工艺,得到了麻疯树毒蛋白,将该蛋白进行抑菌活性研究,得到了如下研究结果：对酿酒酵母、毛霉和根霉具有较强的抑菌活性,对毛霉和根霉的最低抑菌浓度（MIC）不超过1.5 g/L,对酿酒酵母最低抑菌浓度不超过1.0 g/L,而其对大肠杆菌和枯草芽孢杆菌抑菌作用不明显。抑菌的最佳p H值。     

新型吲哚类防污剂抑菌性能评价

对6种含TBG衍生结构的N-取代吲哚衍生物进行了抑菌活性检测。结果表明,各吲哚衍生物对大肠杆菌和金黄色葡萄球菌两种供试菌株均有一定的生长抑制作用,对金黄色葡萄球菌的作用明显优于对大肠杆菌的作用。其中ClG-BP抑菌效果最好,对大肠杆菌和金黄色葡萄球菌最小抑菌质量浓度分别为0.12 mg/mL、0.01 mg/mL。各化合物抑菌性能相对大小为:ClG-BP>ClG>BrG-BP>ClG-MP>BrG>BrG-MP。     

Antibacterial Activity and Amphidinol Profiling of the Marine Dinoflagellate Amphidinium carterae (Subclade III)

Microalgae have received growing interest for their capacity to produce bioactive metabolites. This study aimed at characterising the antimicrobial potential of the marine dinoflagellate Amphidinium carterae strain LACW11, isolated from the west of Ireland. Amphidinolides have been identified as cytotoxic polyoxygenated polyketides produced by several Amphidinium species. Phylogenetic inference assigned our strain to Amphidinium carterae subclade III, along with isolates interspersed in different geographic regions. A two-stage extraction and fractionation process of the biomass was carried out. Extracts obtained after stage-1 were tested for bioactivity against bacterial ATCC strains of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa. The stage-2 solid phase extraction provided 16 fractions, which were tested against S. aureus and E. faecalis. Fractions I, J and K yielded minimum inhibitory concentrations between 16 μg/mL and 256 μg/mL for both Gram-positive. A targeted metabolomic approach using UHPLC-HRMS/MS analysis applied on fractions G to J evidenced the presence of amphidinol type compounds AM-A, AM-B, AM-22 and a new derivative dehydroAM-A, with characteristic masses of m/z 1361, 1463, 1667 and 1343, respectively. Combining the results of the biological assays with the targeted metabolomic approach, we could conclude that AM-A and the new derivative dehydroAM-A are responsible for the detected antimicrobial bioactivity.     

槲皮素酯类衍生物的研究进展

槲皮素,属黄酮醇类化合物,广泛存在于诸如蔬菜、水果、茶和葡萄酒等很多食物中.它是一种极强的天然抗氧化剂,具有抗血栓、抗炎、抗病毒、抗肿瘤等作用.但是,由于其水溶性差,生物利用度低,限制了它的临床应用.近年来,国内外合成了一些槲皮素酯类衍生物,不但改善了槲皮素的水溶性,而且还具有明显的生物活性,如QCI2作为一种水溶性抗...     

槲皮素磺化反应工艺的研究

为提高槲皮素的水溶性,以槲皮素和浓硫酸为原料进行磺化反应制备槲皮素-7-硫酸酯钠。以产率为指标,采用单因素实验和正交实验确定合成槲皮素-7-硫酸酯钠的最佳工艺条件,同时测定了槲皮素及其磺化产物的溶解度。结果表明：槲皮素-7-硫酸酯钠合成的最佳工艺条件为：固液比1：6,反应时间3h,反应温度为10℃,所得槲皮素-7-硫酸酯钠的产率达83．68％,且槲皮素-7-硫酸酯钠在水中的溶解度为940．03μg·mL^-1,比原槲皮素的溶解度增大了195.8倍。采用红外光谱检测、元素分析及^1HNMR等方法对所得产品进行结构表征,说明槲皮素利用A环的7位羟基进行磺化生成硫酸酯盐。     

On the Enhanced Antibacterial Activity of Antibiotics Mixed with Gold Nanoparticles

The bacterial action of gentamicin and that of a mixture of gentamicin and 15-nm colloidal-gold particles on Escherichia coli K12 was examined by the agar-well-diffusion method, enumeration of colony-forming units, and turbidimetry. Addition of gentamicin to colloidal gold changed the gold color and extinction spectrum. Within the experimental errors, there were no significant differences in antibacterial activity between pure gentamicin and its mixture with gold nanoparticles (NPs). Atomic absorption spectroscopy showed that upon application of the gentamicin-particle mixture, there were no gold NPs in the zone of bacterial-growth suppression in agar. Yet, free NPs diffused into the agar. These facts are in conflict with the earlier findings indicating an enhancement of the bacterial activity of similar gentamicin–gold nanoparticle mixtures. The possible causes for these discrepancies are discussed, and the suggestion is made that a necessary condition for enhancement of antibacterial activity is the preparation of stable conjugates of NPs coated with the antibiotic molecules.     

槲皮素及其衍生物的抗肿瘤活性研究进展

总结国内外在槲皮素对肿瘤预防和治疗方面的研究现状。采用ISI、Pub Med和CHKD数据库,检索1994.01~2014.04.06,以"槲皮素"为主题词,共有30 851条英文文献,1 847条中文文献。以"槲皮素、衍生物、肿瘤、预防、治疗"为纳入标准,符合条件的英文文献249条、中文文献44条。槲皮素是一种潜在的癌症化学预防及治疗药物,对多种肿瘤细胞生长具有抑制作用,其机制主要包括调节抑癌基因表达、阻断细胞周期、诱导细胞凋亡、阻滞侵袭及转移以及其显著的抗氧化作用等。对槲皮素进行结构修饰得到的衍生物可有效地改善其水溶性及抗肿瘤活性。槲皮素及其衍生物对多种肿瘤细胞的生长具有抑制作用,槲皮素在肿瘤化学预防方面起着重要作用。     

槲皮素微胶囊的稳定性及缓释性能研究

以大豆蛋白、乙基纤维素、单甘酯作为复合壁材,将槲皮素制成微胶囊产品,探讨了槲皮素微胶囊的稳定性及在不同极性溶剂中的释放性能。结果表明,槲皮素微胶囊化后可以明显提高槲皮素的光稳定性和热稳定性,减弱了pH的影响和氧气对槲皮素的氧化降解。在极性不同的介质中微胶囊槲皮素均具有缓释作用,在极性溶剂水中其缓释能力最强,5％的微胶囊水溶液（W／V）,槲皮素的溶出平衡时间为15h。     

The Impact of Graphite Oxide Nanocomposites on the Antibacterial Activity of Serum

Nanoparticles can interact with the complement system and modulate the inflammatory response. The effect of these interactions on the complement activity strongly depends on physicochemical properties of nanoparticles. The interactions of silver nanoparticles with serum proteins (particularly with the complement system components) have the potential to significantly affect the antibacterial activity of serum, with serious implications for human health. The aim of the study was to assess the influence of graphite oxide (GO) nanocomposites (GO, GO-PcZr(Lys)₂-Ag, GO-Ag, GO-PcZr(Lys)₂) on the antibacterial activity of normal human serum (NHS), serum activity against bacteria isolated from alveoli treated with nanocomposites, and nanocomposite sensitivity of bacteria exposed to serum in vitro (using normal human serum). Additionally, the in vivo cytotoxic effect of the GO compounds was determined with application of a Galleria mellonella larvae model. GO-PcZr(Lys)₂, without IR irradiation enhance the antimicrobial efficacy of the human serum. IR irradiation enhances bactericidal activity of serum in the case of the GO-PcZr(Lys)₂-Ag sample. Bacteria exposed to nanocomposites become more sensitive to the action of serum. Bacteria exposed to serum become more sensitive to the GO-Ag sample. None of the tested GO nanocomposites displayed a cytotoxicity towards larvae.