脱氢松香基1,2,4-三氮唑衍生物的合成及除草活性北大核心CSCD

以脱氢松香酸为原料,经5步反应设计合成了6个新型的脱氢松香基-1,2,4-三氮唑类化合物,对所有目标化合物的结构都进行了1H NMR、IR、MS和元素分析确证。初步的生物活性检测结果表明,所有目标化合物都表现出一定的除草活性。     

脱氢松香基1,2,4-三氮唑衍生物的合成及除草活性

以脱氢松香酸为原料,经5步反应设计合成了6个新型的脱氢松香基-1,2,4-三氮唑类化合物,对所有目标化合物的结构都进行了1H NMR、IR、MS和元素分析确证。初步的生物活性检测结果表明,所有目标化合物都表现出一定的除草活性。     

10种抗生素对厌氧菌体外抗菌活性的研究

本研究采用琼脂平板稀释法测定了6种抗生素对105株临床分离厌氧菌及4种临床常用抗生素对分离的50株类杆菌体外抗菌活性。结果表明:氯林可霉素对所有试验菌株均具极强的抗菌活性,MIC_(90)不超过0.78μg/ml。甲硝唑对类杆菌和梭菌也有很强的抗菌活性,MIC_(90)分别为3.13μg/ml和0.78μg/ml,但对其它种厌氧菌的抗菌活性不强。头孢唑肟、氧哌嗪青霉素对试验菌株的MIC_(50)较小,但对部分菌株的MIC_(90)为25μg/ml,抗厌氧菌的活性有限。头孢噻肟和头孢噻甲羧肟对各类厌氧菌以及头孢噻啶、头孢唑啉、氨苄青霉素和羧苄青霉素对类杆菌的抗菌活性均很弱。     

内生芬芳镰刀菌Dzf2中两个抗菌活性成分(英文)

采用活性追踪的方法从盾叶薯蓣内生芬芳镰刀菌Dzf2中分离到两个抗菌活性成分,通过物理化学性质和波谱学特征鉴定为镰刀菌酸(1)和9,10-脱氢镰刀菌酸(2)。采用多孔板-MTT-比色法和孢子萌发法测定了化合物的抗菌活性。镰刀菌酸和9,10-脱氢镰刀菌酸对供试细菌的半抑制浓度(IC50)值为35.35μg/mL至171.29μg/mL;对稻瘟菌孢子萌发的IC50值分别为28.83μg/mL和27.06μg/mL。     

新的药根碱三唑的合成与抗菌以及乙酰胆碱酯酶抑制活性评价北大核心CSCD

通过有机合成手段合成了四个新的含三唑的药根碱衍生物,利用1H NMR,13C NMR和MS确认了目标化合物的结构,对合成的化合物进行了抗菌和抑制乙酰胆碱酯酶(ACh E)和丁酰胆碱酯酶(Bu Ch E)的活性测试。目标化合物显示具有较好的抗菌活性,抗菌结果显示所制备的化合物抑菌MIC范围从1到64μg/m L,对一些敏感菌的活性和阳性药物罗红霉素相当。对乙酰胆碱酯酶(ACh E)的抑制也表现出较好的活性,IC50值从0.46μM到0.86μM,但这些化合物对丁酰胆碱酯酶(Bu Ch E)表现出较弱的活性IC50>100μM。药根碱三唑具有较好的抑制乙酰胆碱酯酶的活性,且具有较好的选择性,同时具有较好的抗菌活性而且拓展了抗菌谱,可能成为一种新型的抗菌和治疗老年痴呆的先导化合物。     

新的药根碱三唑的合成与抗菌以及乙酰胆碱酯酶抑制活性评价

通过有机合成手段合成了四个新的含三唑的药根碱衍生物,利用1H NMR,13C NMR和MS确认了目标化合物的结构,对合成的化合物进行了抗菌和抑制乙酰胆碱酯酶(ACh E)和丁酰胆碱酯酶(Bu Ch E)的活性测试。目标化合物显示具有较好的抗菌活性,抗菌结果显示所制备的化合物抑菌MIC范围从1到64μg/m L,对一些敏感菌的活性和阳性药物罗红霉素相当。对乙酰胆碱酯酶(ACh E)的抑制也表现出较好的活性,IC50值从0.46μM到0.86μM,但这些化合物对丁酰胆碱酯酶(Bu Ch E)表现出较弱的活性IC50100μM。药根碱三唑具有较好的抑制乙酰胆碱酯酶的活性,且具有较好的选择性,同时具有较好的抗菌活性而且拓展了抗菌谱,可能成为一种新型的抗菌和治疗老年痴呆的先导化合物。     

负载金属离子的5A沸石的体外抗菌实验

目的：探讨负载金属离子的5A沸石的体外抗菌作用。方法：选用金黄色葡萄球菌、铜绿假单孢菌、白色念珠菌,利用倍比稀释法对5A沸石组、磺胺嘧啶银组及载不同浓度Ag＋、Zn2＋5A沸石共15组进行了体外抗菌试验研究,确定最佳抗菌效果离子负载方案。结果：三种细菌的MIC,双金属离子负载在抗菌上具有协同载Ag＋5A沸石分别达到了125μg/ml~500μg/ml、31.25μg/ml~500μg/ml、250μg/ml~500μg/ml;附载Zn2＋5A沸石分别达到了12.5mg/ml~25mg/ml、6.25mg/ml~50mg/ml、25mg/ml;负载双离子5A沸石分别为250μg/ml~500μg/ml、62.5μg/ml~500μg/ml、500μg/ml。结论：5A沸石负载金属离子后均具有抗菌作用,且抗菌作用与附载金属离子的量正相关;负载相同质量Ag＋的5A沸石较附载Zn2＋者具有更强的抗菌作用;双金属离子负载在抗菌上具有协同作用;2%Ag＋＋8%Zn2＋与2%Ag＋＋10%Zn2＋及4%载银组与阳性对照组无显著性差异。     

负载金属离子的5A 沸石的体外抗菌实验

目的:探讨负载金属离子的5A沸石的体外抗菌作用。方法:选用金黄色葡萄球菌、铜绿假单孢菌、白色念珠菌,利用倍比稀释法对5A沸石组、磺胺嘧啶银组及载不同浓度Ag+、Zn2+5A沸石共15组进行了体外抗菌试验研究,确定最佳抗菌效果离子负载方案。结果:三种细菌的MIC,双金属离子负载在抗菌上具有协同载Ag+5A沸石分别达到了125μg/ml~500μg/ml、31.25μg/ml~500μg/ml、250μg/ml~500μg/ml;附载Zn2+5A沸石分别达到了12.5mg/ml~25mg/ml、6.25mg/ml~50mg/ml、25mg/ml;负载双离子5A沸石分别为250μg/ml~500μg/ml、62.5μg/ml~500μg/ml、500μg/ml。结论:5A沸石负载金属离子后均具有抗菌作用,且抗菌作用与附载金属离子的量正相关;负载相同质量Ag+的5A沸石较附载Zn2+者具有更强的抗菌作用;双金属离子负载在抗菌上具有协同作用;2%Ag++8%Zn2+与2%Ag++10%Zn2+及4%载银组与阳性对照组无显著性差异。     

溴化马来松香的合成、表征及其阻燃性的研究

本文以马来松香与液溴加成,合成了溴化马来松香;研究了反应温度、原料的摩尔比、反应时间等因素对反应过程及产物性能的影响.用FT-IR、1H NMR和TG对溴化马来松香进行了表征.结果表明,当反应温度为-2～6℃,反应时间5～6 h,反应物的当量配比约为1.2时,收率可达87.9%.溴化马来松香具有较好的阻燃性,同时也拓宽了松香的应用范围,提高了松香的附加值.     

马来松香基双硫脲-酰胺化合物的合成及抑菌活性

以天然产物松香为原料,先制备马来松香,再经多步反应,合成得到10个新型马来松香基双硫脲-酰胺化合物7a~7j。用FT-IR、1H NMR、13C NMR、ESI-MS和UV-vis等多种方法对目标产物作了分析和表征。初步的生物活性测试表明,在50μg/m L浓度下,目标化合物对5种植物病原菌表现出一定的抑菌活性;大部分化合物对苹果轮纹病菌的抑制率超过60%,其中化合物7i的抑制率达71. 4%(B级活性水平)。     

Highly effective, water-soluble, hemocompatible 1,3-propylene oxide-based antimicrobials: poly[(3,3-quaternary/PEG)-copolyoxetanes

This study focuses on the solution antimicrobial effectiveness of a novel class of copolyoxetanes with quaternary ammonium and PEG-like side chains. A precursor P[(BBOx-m)(ME2Ox)] copolyoxetane was prepared by cationic ring-opening copolymerization of 3-((4-bromobutoxy)methyl)-3-methyloxetane (BBOx) and 3-((2-(2-methoxyethoxy)ethoxy)methyl)-3-methyloxetane (ME2Ox) to give random copolymers with 14-100 (m) mol % BBOx. Reaction of P[(BBOx-m)(ME2Ox)] with dodecyl dimethylamine gave the corresponding quaternary P[(C12-m)(ME2Ox)] polycation salts, designated C12-m, as viscous liquids in 100% yield. BBOx/ME2Ox and C12/ME2Ox ratios were obtained by (1)H NMR spectroscopy. C12-m molecular weights (M(n), 3.5-21.9 kDa) were obtained from (1)H NMR end group analysis. DSC studies up to 150 °C showed only thermal transitions between -69 and -34 °C assigned to T(g) values. Antibacterial activity for the C12-m copolyoxetanes was tested by determining minimum inhibitory concentrations (MICs) against Gram(+) Staphylococcus aureus and Gram(-) Escherichia coli and Pseudomonas aeruginosa . MIC decreased with increasing C12 mol percent, reaching a minimum in the range C12-43 to C12-60. Overall, the antimicrobial with consistently low MICs for the three tested pathogenic bacteria was C12-43: (bacteria, MIC, μg/mL) E. coli (6), S. aureus (5), and P. aeruginosa (33). For C12-43, minimum biocidal concentration (MBC) to reach 99.99% kill in 24 h required 1.5× MIC for S. aureus and 2× MIC for E. coli and P. aeruginosa . At 5× MIC against a challenge of 10(8) cfu/mL, C12-43 kills ≥99% S. aureus , E. coli , and P. aeruginosa within 1 h. C12-m copolyoxetane cytotoxicity toward human red blood cells was low, indicating good prospects for biocompatibility. The tunability of C12-m copolyoxetane compositions, effective antimicrobial behavior against Gram(+) and Gram(-) bacteria, and promising biocompatibility offer opportunities for further modification and potential applications as therapeutic agents.     

黑大蒜提取物联合抗生素对金黄色葡萄球菌和肠埃希菌的体外抗菌作用研究

评价黑大蒜提取物分别与头孢唑林或庆大霉素联合应用,对金黄色葡萄球菌和大肠埃希菌的体外抗菌效应。采用液体稀释法分别测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的最低抑菌浓度（MIC）。采用棋盘法设计,微量肉汤稀释法测定黑大蒜提取物联合头孢唑林或庆大霉素对金黄色葡萄球菌和大肠埃希菌的MIC,并计算部分抑菌浓度（FIC指数）。测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的时间-杀菌曲线。黑大蒜提取物对金黄色葡萄球菌的MIC为256μg/mL,黑大蒜提取物对大肠埃希菌的MIC为256μg/mL。时间-杀菌曲线结果显示黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的抑菌作用呈现较强的浓度依赖性。黑大蒜提取物联合头孢唑林后对金黄色葡萄球菌的FIC指数为0.75;黑大蒜提取物联合庆大霉素后对大肠埃希菌的FIC指数为0.5。黑大蒜提取物与头孢唑林或庆大霉素联合用药,可明显降低抗生素对金黄色葡萄球菌和大肠埃希菌的MIC,表现为相加和协同效应。     

AgNO3对大肠杆菌和金黄色葡萄球菌的抗菌作用及机制

以大肠杆菌和金黄色葡萄球菌为模式菌,对AgNO3的抗菌效果进行研究,并对其抗菌机制作初步探讨。AgNO3对大肠杆菌的抑制生长曲线表明:2.891 mg/L的AgNO3能够完全抑制106个/mL的大肠杆菌细胞生长,AgNO3使大肠杆菌和金黄色葡萄球菌的延滞期加长,并且浓度越高,延滞期越长。另外,AgNO3对大肠杆菌和金黄色葡萄球菌脱氢酶的活性有明显影响,随着AgNO3浓度的提高,脱氢酶的活性逐渐降低。AgNO3溶液作用于细菌后,细菌表面疏水性均有不同程度地下降,且浓度越大对其影响也越明显,大肠杆菌的下降程度要大于金黄色葡萄球菌。     

Synthesis and potent antimicrobial activity of some novel methyl or ethyl 1H-benzimidazole-5-carboxylates derivatives carrying amide or amidine groups

A series of benzimidazole-5-carboxylic acid alkyl ester derivatives carrying amide or amidine substituted methyl or phenyl groups at the position C-2 were synthesised and evaluated for antibacterial and antifungal activities against S. aureus, methicillin resistant S. aureus (MRSA), S. faecalis, methicillin resistant S. epidermidis (MRSE), E. coli and C. albicans. The results showed that while all simple acetamides are essentially inactive, aromatic amides and amidines have potent antibacterial activities. Aromatic amidine derivatives 13 f-h exhibited the best inhibitory activity with 1.56-0.39 microg/mL MIC values against MRSA and MRSE.     

Factors influencing potent antagonistic effects of Escherichia coli and Bacteroides ovatus on Staphylococcus aureus in anaerobic continuous flow cultures

We examined factors related to the potent antagonistic effect of Escherichia coli and Bacteroides ovatus on Staphylococcus aureus in anaerobic continuous flow cultures. In the presence of sugars fermentable by E. coli alone or both E. coli and S. aureus, motile E. coli strains exerted a potent antagonistic effect and S. aureus was expelled from the culture vessel within a few days. Conversely, in the presence of a sugar fermentable by S. aureus alone, the antagonistic effect of E. coli was diminished and S. aureus persisted at ca. 5 x 10(5) cfu/mL. B. ovatus alone exerted only a weak antagonistic effect on S. aureus in any culture conditions; however, when B. ovatus was cocultivated with E. coli and S. aureus, even in the presence of a sugar fermentable by S. aureus but not by E. coli, the potent antagonistic effect was restored. Escherichia coli showed the same level of antagonistic effect either in the presence of acetic acid (ca. 32 mM), propionic acid (4 mM), butyric acid (17 mM) and hydrogen sulfide (5 x 10(-1) mM) or when these metabolic products, except for a small amount of acetic acid (1.2 mM) were not present. In these culture conditions, S. aureus populations were lost at rates much higher than theoretical wash out rates of resting cells. These results indicate the presence of some bactericidal factors other than the volatile fatty acids and hydrogen sulfide. The bactericidal factors were not found in cultures of E. coli heated in boiling water for 10 min and in cell-free culture filtrates. Thus, the bactericidal factors seem to be associated with live E. coli cells. The nature of the bactericidal factors is not clear at present.     

Antibacterial polypropylene via surface-initiated atom transfer radical polymerization

Polypropylene (PP) coated by a non-leachable biocide was prepared by chemically attaching poly(quaternary ammonium) (PQA) to the surface of PP. The well-defined poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), a precursor of PQA, was grown from the surface of PP via atom transfer radical polymerization (ATRP). The tertiary ammine groups in PDMAEMA were consequently converted to QA in the presence of ethyl bromide. Successful surface modification was confirmed by ATR-FTIR, contact angle measurement, and an antibacterial activity test against Escherichia coli (E. coli). The biocidal activity of the resultant surfaces depends on the amount of the grafted polymers (the number of available quaternary ammonium units). With the same grafting density, the surface grafted with relatively high MW polymers (M(n) > 10,000 g/mol) showed almost 100% killing efficiency (killing all of the input E. coli (2.9 x 10(5)) in the shaking test), whereas a low biocidal activity (85%) was observed for the surface grafted with shorter PQA chains (M(n) = 1,500 g/mol).     

莳萝蒿精油成分分析及抑菌活性机理探究

为了确定莳萝蒿精油的化学成分,并探究其抑菌活性及抑菌机理.该研究采用水蒸气蒸馏法提取莳萝蒿精油,并通过气相色谱-质谱联用法测定其化学成分.采用抑菌圈法、二倍稀释法和生长曲线法测定精油的抑菌活性,采用电导率法和扫描电镜法探究精油的抑菌机理.结果表明:(1)莳萝蒿精油的主要化学成分包括醇类(47.12％)和萜烯类(19.9...     

From multifunctionalized poly(ethylene imine)s toward antimicrobial coatings

Primary amine groups of branched poly(ethylene imine) (PEI) were functionalized with quaternary ammonium groups, alkyl chains of different length, allylic and benzylic groups in a one-step reaction, using a carbonate coupler. The structure of the obtained amphiphilic polymers was determined by means of 1H and 13C NMR spectroscopy. Depending on their hydrophilic/hydrophobic balance, the obtained polymers can be used as water-soluble disinfectants and for antimicrobial coating materials. The bactericidal properties of some of the amphiphilic polymers against Gram-negative and Gram-positive bacteria were investigated. Minimal inhibitory concentrations (log 4 reduction of bacterial growth) against Escherichia coli and Bacillus subtilis were determined in the range of 0.3-0.4 mg/mL and 0.03-0.04 mg/mL for water-soluble polymers. Glass slides coated with functionalized PEIs showed a reduction of colony forming units of at least 95%, at best 99.9%, against E. coli and B. subtilis.     

Antibacterial action of a heat-stable form of L-amino acid oxidase isolated from king cobra (Ophiophagus hannah) venom

The major l-amino acid oxidase (LAAO, EC 1.4.3.2) of king cobra (Ophiophagus hannah) venom is known to be an unusual form of snake venom LAAO as it possesses unique structural features and unusual thermal stability. The antibacterial effects of king cobra venom LAAO were tested against several strains of clinical isolates including Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli using broth microdilution assay. For comparison, the antibacterial effects of several antibiotics (cefotaxime, kanamycin, tetracycline, vancomycin and penicillin) were also examined using the same conditions. King cobra venom LAAO was very effective in inhibiting the two Gram-positive bacteria (S. aureus and S. epidermidis) tested, with minimum inhibitory concentration (MIC) of 0.78μg/mL (0.006μM) and 1.56μg/mL (0.012μM) against S. aureus and S. epidermidis, respectively. The MICs are comparable to the MICs of the antibiotics tested, on a weight basis. However, the LAAO was only moderately effective against three Gram-negative bacteria tested (P. aeruginosa, K. pneumoniae and E. coli), with MIC ranges from 25 to 50μg/mL (0.2-0.4μM). Catalase at the concentration of 1mg/mL abolished the antibacterial effect of LAAO, indicating that the antibacterial effect of the enzyme involves generation of hydrogen peroxide. Binding studies indicated that king cobra venom LAAO binds strongly to the Gram-positive S. aureus and S. epidermidis, but less strongly to the Gram-negative E. coli and P. aeruginosa, indicating that specific binding to bacteria is important for the potent antibacterial activity of the enzyme.     

Synthesis and antimicrobial activity of a water-soluble chitosan derivative with a fiber-reactive group

A novel fiber-reactive chitosan derivative was synthesized in two steps from a chitosan of low molecular weight and low degree of acetylation. First, a water-soluble chitosan derivative, N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride (HTCC), was prepared by introducing quaternary ammonium salt groups on the amino groups of chitosan. This derivative was further modified by introducing functional (acrylamidomethyl) groups, which can form covalent bonds with cellulose under alkaline conditions, on the primary alcohol groups (C-6) of the chitosan backbone. The fiber-reactive chitosan derivative, O-acrylamidomethyl-HTCC (NMA-HTCC), showed complete bacterial reduction within 20 min at the concentration of 10ppm, when contacted with Staphylococcus aureus and Escherichia coli (1.5-2.5 x 10(5) colony forming units per milliliter [CFU/mL]).