2种蓼科植物体外抑菌试验研究

为研究蓼科植物水蓼、火炭母体外抑菌效果,制备水煎煮液,测定其对枯草芽胞杆菌、大肠埃希菌、金黄色葡萄球菌、黑曲霉、青霉、酿酒酵母的抑菌圈直径、最小抑菌浓度及灭菌前后水煎煮液抑菌效果的变化。结果表明：当水蓼液浓度大于0.6 g/mL,火炭母液浓度大于0.2 g/mL时,2者对细菌的抑菌效果均依次为：金黄色葡萄球菌〉大肠埃希菌〉枯草芽胞杆菌。2种水煎煮液对3种真菌无抑制作用。火炭母液对3种细菌的最小抑菌浓度分别为1/8、1/16和1/64 g/mL,都比水蓼液的结果1/4、1/8和1/16 g/mL低。药液经121℃高压蒸汽灭菌处理后,水蓼液对3种细菌的抑制作用有所增强,火炭母液则对金黄色葡萄球菌的抑制作用有所增强。2种水煎煮液对3种细菌均有不同程度的抑制作用,可考虑以其为原料进行植物源抗菌剂的开发,拓宽其应用领域。     

薇甘菊水提物的抑菌试验研究

以枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌为代表,分别探讨了薇甘菊水溶性提取物对上述3种细菌在培养24 h过程中的光密度、活菌数和最低杀菌浓度的影响。试验结果表明,在一定浓度范围内薇甘菊水提物对上述3种细菌均有不同程度的抑制作用。其中,枯草芽孢杆菌的抑制作用最强,其次是大肠杆菌和金黄色葡萄球菌。透射电镜观察结果表明,薇甘菊水提物可抑制金黄色葡萄球菌细胞壁的分离,因而抑制了细胞的分裂而达到抑菌效果。     

木贼生物碱的提取及其功能的研究

以木贼为研究对象,提取生物碱,并对其体外抗氧化及抑菌功能进行研究,采用乙醇提取法和盐酸提取法确定生物碱的最佳提取条件,并研究木贼生物碱对羟自由基、超氧自由基、DPPH自由基的清除效率及其对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌的抑制效果。当乙醇浓度80%、料液比13 mL/g、浸泡时间18 h、浸提液pH值5时,木贼生物碱的提取含量最高。研究发现,木贼生物碱对羟自由基、超氧自由基、DPPH自由基的清除能力随着生物碱浓度提高而增强,其中对DPPH自由基的清除效果最佳,达到98.1%。木贼生物碱对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌均有一定的抑菌效果,最明显的是大肠杆菌,抑菌浓度为5 mg/mL。木贼生物碱通过乙醇提取效果较好,且体外抗氧化及对大肠杆菌等具有明显的抑制作用。本研究可为广泛应用木贼的药用价值奠定基础。     

麻叶荨麻籽抑菌成分和抑菌特性的研究

目的：为了确定麻叶荨麻籽的抑菌成分和其抑菌特性。方法：以麻叶荨麻籽的不同提取物为抑菌剂进行抑菌。结果：麻叶荨麻籽的抑菌活性部位是石油醚和乙酸乙脂提取物,其中石油醚提取物的抑菌作用最强,对大肠杆菌和枯草芽孢杆菌的最低抑菌浓度是1．25mg/mL,金黄色葡萄球菌是2．5mg/mL。麻叶荨麻籽抗菌活性成分是：酚类、鞣质、有机酸等化合物。石油醚提取物对三种细菌脲酶活性均有不同程度的抑制作用。结论：麻叶荨麻籽提取物是较为有效的抑菌物。     

樟叶乙醇提取液的抑菌作用

樟叶的乙醇提取物对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、汉逊氏酵母菌、青霉、毛霉有一定的抑菌作用。其最低抑菌浓度对三种细菌及酵母为 12 .5m g/ ml,对青霉、毛霉为 2 5m g/ m l     

家蝇幼虫血淋巴粗提物抑菌活性初步研究

以4种细菌(大肠杆菌、金黄色葡萄球菌、巨大芽孢杆菌、枯草芽孢杆菌)为供试菌,测定了家蝇幼虫血淋巴粗提物的抑菌活性。结果显示,家蝇幼虫血淋巴各浓度粗提物对4种供试细菌均有一定的抑菌活性,其中对金黄色葡萄球菌的抑菌率最大,其他依次为大肠杆菌>枯草芽胞杆菌>巨大芽孢杆菌,在0.8mg/mL时的抑菌率分别为51.09%、48.66%、43.27%和40.62%;在各浓度下不同菌种之间的抑菌率差异不显著,抑菌活性随着血淋巴粗提物浓度的增加而增强。在0.8mg/mL时对各细菌的抑菌圈直径分别为12.00mm、12.22mm、9.11mm和10.33mm,均显著大于对照,但低于头孢霉素。     

葛根素提取及其抑菌实验研究

以湘西葛根为实验材料,选取水、甲醇和95％的乙醇作为提取溶剂,索氏提取法提取其葛根素。以提取率为指标,综合提取工艺中加入量、提取时间的影响,采用正交实验筛选出乙醇提取工艺,最佳参数为每次加入10倍量、回流提取时间3．5h。用滤纸片法研究葛根提取液对大肠杆菌等8种常见食品腐败菌的抑菌活性,结果表明,各种菌体的抑菌效果为：大肠杆菌〉金黄色葡萄球菌〉枯草芽孢杆菌〉假丝酵母青霉,对青霉无抑菌作用。各种菌的抑菌效果与浓度的关系为,葛根素浓度升高,抑菌效果增强。     

辣椒素的提取及抑菌活性研究

以干红辣椒为原料,选取95%的乙醇和正己烷作为提取溶剂,利用索氏提取法提取其中的辣椒素。结果表明,以95%的乙醇作为提取溶剂的效果好于正己烷,辣椒素的提取率最高可达1.77%,高于正己烷的1.12%的提取率。用滤纸片法研究辣椒素对大肠杆菌等8种常见食品腐败菌的抑菌活性。结果表明:辣椒素对金黄色葡萄球菌、枯草芽孢杆菌有明显的抑菌效果,对大肠杆菌抑菌作用较弱,对黑曲霉、青霉、保加利亚乳酸杆菌和噬热链球菌没有作用。辣椒素经过高温灭菌后,抑菌作减弱,培养时间对抑菌圈的影响不大。以正己烷为助溶剂,确定辣椒素对枯草芽孢杆菌的最低抑菌浓度(MIC)为50mg/mL。     

云南省4种蕨类植物提取液的抑菌活性

为了合理开发利用蕨类植物资源,本研究利用圆纸片法分析了云南省4种蕨类植物单芽狗脊蕨(Woodwardia unigemmata)、蜈蚣蕨(Pteris vittata)、鸡足山耳蕨(Polystichum jizhushanense)和灰绿耳蕨(Polystic-hum eximium)的提取液对金黄色葡萄球菌(Staphylococus aureus)、大肠杆菌(Escherichia coli)和枯草芽孢杆菌(Bacillus subtilis)的抑菌活性。抑菌试验结果表明,当4种蕨类植物提取液浓度分别为10%、8%、6%和4%时,对照组无抑菌圈出现,单芽狗脊蕨提取液对大肠杆菌和金黄色葡萄球菌无抑菌活性,灰绿耳蕨提取液对金黄色葡萄球菌无抑菌活性,其它的蕨类植物提取液对供试微生物都表现出不同程度的抑菌活性;并且这4种蕨类植物提取液至少对一种供试细菌具有抑菌活性,抑菌活性范围为8～14mm,平均抑菌圈直径为11.2mm,4种提取液对枯草芽孢杆菌抗菌活性效果最明显。由此,我们推测本研究中的4种蕨类植物均有抗菌物质存在,并将有望成为筛选抗菌新型药物的种质资源。     

番石榴叶中总黄酮最佳提取条件的探讨及其抑菌作用的研究

设计正交实验,采用超声波法从番石榴叶中提取总黄酮,综合各因素确定最佳提取条件为乙醇浓度40％,固料比（番石榴干叶：浸提剂）=1g：60mL,浸泡25h超声波处理时间50min,获得提取液总黄酮含量为9．9167％。采用牛津杯法做抑菌实验,结果表明番石榴叶和果实的水提、醇提粗提液对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、阴沟肠杆菌、溶血葡萄球菌等均有很好的抑菌效果。叶和果实的总黄酮提取液的抑菌作用也很明显。番石榴有望作为药食同源产品和天然食品防腐剂进行开发利用。     

墨旱莲提取物抑菌活性初步研究

对药用植物墨旱莲Eclipta prostrata提取物的抑菌活性物质进行研究。结果表明：（1）通过不同部位提取物的抑菌试验,发现只有叶和根茎含有抑菌活性物质;（2）墨旱莲提取物对金黄色葡萄球菌、大肠杆菌、枯草杆菌、藤黄球菌的最低抑菌浓度分别为0.6、2.0、0.8、1.0 g/mL,最小杀菌浓度均为1.0 g/mL,对白色念珠菌有很强的抑菌作用,但对黑曲霉无效;（3）通过不同极性溶剂的抑菌试验表明,抑细菌活性物质易溶于石油醚、乙醚等非极性溶剂,具有最佳抑细菌效果的提取溶剂为偏碱性的65%乙醇溶液;（4）墨旱莲的抑菌活性物质可能为黄酮类物质。     

华南十大功劳提取物抑菌活性初步研究

以超声提取和索氏提取方法,比较华南十大功劳叶和茎提取物经不同溶剂和不同极性萃取物萃取的抑菌活性大小。结果表明,叶和茎均含有抑菌活性物质,而叶的抑菌效果更强;索氏提取物与超声提取抑菌效果差异不大;华南十大功劳提取物对金黄色葡萄球菌、大肠杆菌、枯草杆菌、藤黄球菌、白色念珠菌的最低抑菌浓度分别为0.6 g/mL、1.0 g/mL、0.8 g/mL、1.0 g/mL、2.0 g/mL;其最小杀菌浓度均为2.0 g/mL,但其对黑曲霉没有抑制作用;不同溶剂提取物中,无水甲醇溶液提取物具有最佳抑菌效果。提取物易溶解于极性萃取物。5种敏感菌对华南十大功劳提取物的敏感性由强到弱依次为：金黄色葡萄球菌菌＞枯草杆菌＞藤黄球菌＞大肠杆菌＞白色念珠菌。     

苍术体外抑菌活性的初步研究

对苍术的体外抑菌活性进行初步的研究。通过用体积分数为50％乙醇浸泡、有机溶剂萃取、薄层层析对苍术抑菌活性物质进行初步分析,用纸片法检测其抑菌活性,用琼脂稀释法测最低抑菌浓度（MIC）。结果表明：苍术提取液对金黄色葡萄球菌的抑菌作用较明显,对白色念珠菌和大肠杆菌的抑菌作用次之,其最低抑茵质量浓度分别为0．7g／mL,1．0g/mL和1．2g/mL;以正丁醇作为萃取液抑菌效果最佳,薄层层析实验结果表明,Rf值为0．76的展开点具有抑菌活性。     

一株来自于伊犁贝母的内生尖孢镰孢菌Y1的抑菌活性初步研究

从新疆巩留县伊犁贝母的新鲜鳞茎中分离到一株具有分泌抑菌活性物质的内生尖孢镰孢菌Fusarium oxysporumY1,该菌在7种不同培养基上生长时显示出不同的菌落生长特征,而且只在沙氏培养基中生长时才具有分泌抑菌活性物质的能力。抑菌活性筛选结果表明:由该菌及其发酵液制备的发酵液浸膏、菌体裂解液浸膏以及经进一步纯化后获得的乙酸乙酯浸膏和正丁醇浸膏均具有明显的抑菌活性,其中以发酵液的乙酸乙酯浸膏和菌体裂解液的正丁醇浸膏活性最强,它们对金黄色葡萄球菌Staphylococcus aureus、表皮葡萄球菌Staphylococcus epidermidis、枯草芽孢杆菌Bacillus subtilis、藤黄八叠球菌Sarcina lutea和大肠杆菌Escherichia coli的最低抑菌浓度均小于25μg/mL。     

4种中药贯众原植物提取物的体外抗菌活性研究

用水提法和醇提法制备苏铁蕨（Brainea insighis）、华南紫萁（Osmunda vachellii）、狗脊蕨（Woodwardia japonica）和乌毛蕨（Blechnum orientale）的根状茎的提取液,应用纸片扩散法和试管二倍稀释法测定了各提取液对11种常见致病菌的抑菌圈、最低抑菌浓度（MIC）和最低杀菌浓度（MBC）。结果表明,各提取液（1g生药／mL）对表皮葡萄球菌、枯草芽孢杆菌、金黄色葡萄球菌及李斯特菌4种革兰氏阳性菌有明显抑制作用,对表皮葡萄球菌的抑制作用尤为明显,且醇提液的抑菌效果优于水提液;对大肠埃希氏菌等革兰氏阴性菌则无抑制作用。在4种贯众原植物中,苏铁蕨对革兰氏阳性菌的抑制活性最强。     

Antioxidant,antibacterial and cytotoxic potential of silver nanoparticles synthesized using terpenes rich extract of Lantana camara L. leaves

Several attempts have been made for green synthesis of silver nanoparticles (AgNPs) using different plant extracts. Present study revealed that, antioxidant, antibacterial and cytotoxic AgNPs were synthesized using terpenes-rich extract (TRE) of environmentally notorious Lantana camara L. leaves. AgNPs were characterized by advanced techniques like UV–Visible and Infra red spectroscopy; XRD, SEM techniques as terpenes coated sphere shaped NPs with average diameter 425 nm. Further, on evaluation, AgNPs were found to exhibit dose – dependent antioxidant potential, good to moderate antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa; and toxicity on Brine shrimp (A. salinanauplii) with LD₅₀ value 514.50 µg/ml.     

马缨丹叶片水提物与挥发油的生物活性及化学成分研究

研究了马缨丹 ( Lantana camara L.)叶片水提物和挥发油水溶液的化感作用。结果表明 ,马缨丹叶片水溶物浓度在 0 .2 5 g FW m L- 1时 ,对所有受试植物的幼苗生长均有一定的抑制作用 ,浓度降至 0 .1 0 g FWm L- 1时 ,其抑制作用显著降低 ;马缨丹叶片挥发油水溶液在浓度为 1 0 0、2 0 0、30 0 μg m L- 1时 ,对受试植物均有很强的抑制作用 ,且具有明显的浓度效应。采用 GC/MS分析了马缨丹叶片挥发油的化学成分 ,鉴定了 1 9种化感物质 ,其中α-子丁香烯和β-子丁香烯为主要物质 ,分别占挥发油含量的 1 6 .2 9%、2 2 .2 9%。     

Antibacterial activity of extracts and neolignans from Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck

The evaluation of the activity of the aqueous and ethyl acetate extracts of the leaves of Piper regnellii was tested against gram-positive and gram-negative bacteria. The aqueous extract displayed a weak activity against Staphylococcus aureus and Bacillus subtilis with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of 1000 micrograms/ml. The ethyl acetate extract presented a good activity against S. aureus and B. subtilis with MIC and MBC at 15.62 micrograms/ml. In contrast to the relative low MICs for gram-positive bacteria, gram-negative bacteria were not inhibited by the extracts at concentrations < or = 1000 mg/ml. The ethyl acetate extract was fractionated on silica gel into nine fractions. The hexane and chloroform fractions were active against S. aureus (MIC at 3.9 micrograms/ml) and B. subtilis (MIC at 3.9 and 7.8 micrograms/ml, respectively). Using bioactivity-directed fractionation, the hexane fraction was rechromatographed to yield the antimicrobial compounds 1, 2, 5, and 6 identified as eupomatenoid-6, eupomatenoid-5, eupomatenoid-3, and conocarpan, respectively. The pure compounds 1 and 2 showed a good activity against S. aureus with MIC of 1.56 micrograms/ml and 3.12 micrograms/ml, respectively. Both compounds presented MIC of 3.12 micrograms/ml against B. subtilis. The pure compound 6 named as conocarpan was quite active against S. aureus and B. subtilis with MIC of 6.25 micrograms/ml. The antibacterial properties of P. regnellii justify its use in traditional medicine for the treatment of wounds, contaminated through bacteria infections.     

Antimicrobial activity of endemic Crataegus tanacetifolia (Lam.) Pers and observation of the inhibition effect on bacterial cells

Up to now an increasing number of antibiotic-resistant bacteria have been reported and thus new natural therapeutic agents are needed in order to eradicate these pathogens. Through the discovery of plants such as Crataegus tanacetifolia (Lam.) Pers that have antimicrobial activity, it will be possible to discover new natural drugs serving as chemotherapeutic agents for the treatment of nosocomial pathogens and take these antibiotic-resistant bacteria under control. The objective of the present study was to determine antimicrobial activity and the activity mechanism of C. tanacetifolia plant extract. The leaves of C. tanacetifolia, which is an endemic plant, were extracted using methanol and tested against 10 bacterial and 4 yeast strains by using a drop method. It was observed that the plant extract had antibacterial effects on Bacillus subtilis, Shigella, Staphylococcus aureus, and Listeria monocytogenes among the microorganisms that were tested. Minimum inhibitory concentration (MIC) results obtained at the end of an incubation of 24 h were found to be > or =6.16 mg ml(-1) for B. subtilis, < 394 mg ml(-1) for Shigella, and > or =3.08 mg ml(-1) for L. monocytogenes and S. aureus and minimum bactericidal concentration (MBC) were found as > or =24.63 mg ml(-1) for B. subtilis, > or =394 mg ml(-1) for Shigella, > or =6.16 mg ml(-1) for L. monocytogenes, and > or =98.5 mg ml(-1) for S. aureus. According to the MBC results, it was found that the plant extract had bactericidal effects and in order to explain the activity mechanism and cell deformation of bacterial strains treated with plant extract, the scanning electron microscopy (SEM) was used. The results of SEM showed that the treated cells appeared shrunken and there was degradation of the cell walls. This study, in which the antibacterial effect of C. tanacetifolia was demonstrated, will be a base for further investigations on advanced purification and effect mechanism of action of its active compounds.     

Antibacterial xanthones from Kielmeyera variabilis mart. (Clusiaceae)

The bioassay-guided fractionation of stems from Kielmeyera variabilis, traditionally used in Brazilian folk medicine, yielded assiguxanthone-B (1), kielcorin (4), 2,5-dihydroxybenzoic acid (3), and a mixture of xanthones containing assiguxanthone-B (1) and 1,3,5,6-tetrahydroxy-2-prenylxanthone (2) (1:1 w/w). The xanthone mixture inhibited Staphylococcus aureus and Bacillus subtilis at a concentration of 6.25 g/ml. When tested alone, the minimal inhibitory concentration of assiguxanthone-B was 25 g/ml against B. subtilis. Kielcorin and 2,5-dihydroxybenzoic acid were inactive against both strains. None of the fractions was active against Escherichia coli or Pseudomonas aeruginosa. Viable cells of S. aureus were reduced by a 1-3 log CFU/ml within 12 h after exposure of one to eight times the MIC of the xanthone mixture. It is not known whether the tetrahydroxy-2-prenylxanthone or other components of the xanthone mixture are responsible for the main antibacterial activity or whether additive or synergistic action is involved