红葱不同极性提取物抑菌活性研究

选用3种常见的食源性菌金黄色葡萄球菌ATCC25923、大肠杆菌ATCC25922、鼠伤寒沙门氏菌ATCC14028作为供试菌种,采用试管二倍稀释法定量测定红葱乙醇粗提液(1 g/L)的最低抑菌浓度(MIC)和最低杀菌浓度(MBC),并用打孔法分别测定红葱石油醚、乙酸乙酯、氯仿、正丁醇和乙醇不同极性提取物的抑菌圈大小。结果表明:乙醇粗提液对金黄色葡萄球菌的MIC和MBC值分别为3. 91 mg/mL,与7. 81 mg/mL,红葱不同极性提取物对3种细菌均有不同程度的抑制作用,对金黄色葡萄球菌高度敏感。石油醚提取部位活性最强,其对金黄色葡萄球菌的最大抑菌直径达31. 83±0. 50 mm。实验结果为红葱提取物进一步在食品天然防腐剂的开发应用提供参考依据。     

西瓜藤提取物的抑菌作用研究

采用琼脂稀释法研究西瓜藤提取物的体外抑菌作用,用小鼠腹腔注射金黄色葡萄球菌法研究80%醇提物的体内抑菌作用。结果表明:西瓜藤提取物对金黄色葡萄球菌、大肠埃希氏菌、铜绿假单胞菌、伤寒沙门氏菌、枯草芽孢杆菌和肺炎克雷伯氏菌均有不同程度的抑制作用,但对链球菌作用不明显。其中80%醇提取物和乙酸乙酯萃取物抑制金黄色葡萄球菌活性最好,其最低抑菌浓度(MIC)分别为4.2、8.4mg.mL-1。体内实验也表明,乙醇提取物具有较好的抑菌作用。西瓜藤提取物具有抑菌活性,在抑菌方面有一定开发前景。     

脱油油樟叶提取物的体外抑菌活性研究

探讨了油樟叶提取挥发油后的残渣的乙醇浸膏和乙醇浸膏的石油醚萃取相、乙酸乙酯萃取相、正丁醇萃取相和水萃取相对大肠杆菌、金黄色葡萄球菌、沙门氏菌等三种常见致病菌的最低抑菌浓度(MIC)、最低杀菌浓度(MBC)以及抑菌曲线.结果显示,各提取物对大肠杆菌的抑菌活性为正丁醇萃取相(MIC、MBC:7.813、15.625 mg/...     

三种芦荟汁的抑菌活性及其影响因素研究

目的：探索美国库拉索芦荟、日本木立芦荟和中华芦荟汁液的抑菌作用。方法：测定三种芦荟叶片提取物对一系列供试细菌和真菌的最低抑菌浓度（MIC）、最低杀菌浓度（MBC）,对比121℃热处理30min前后提取物对金黄色葡萄球菌的抑菌作用。结果：三种芦荟提取物对供试细菌的金黄色葡萄球菌最低抑菌浓度均为0.4%;对供试菌真菌的黑曲霉都有不同程度的抑制作用,其最低抑菌浓度为0.2%。热处理后抑菌效应没有明显的下降。结论：芦荟叶提取物的抑菌作用随浓度的增加和抑菌时间的延长而增强,热处理不会影响其抑菌效果。     

甘草提取物对四种牙周常见致病菌的抑菌作用

目的体外评价甘草提取物对牙龈卟啉单胞菌、中间普氏菌、具核梭杆菌和伴放线放线杆菌四种牙周常见致病菌的抑制效果。方法以牙龈卟啉单胞菌、中间普氏菌、具核梭杆菌和伴放线放线杆菌四种牙周常见致病菌作为供试菌,采用液体稀释法,考察甘草提取物对这四种细菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC);并采用不同浓度的甘草提取物溶液,绘制甘草提取物对四种牙周致病菌的时间-杀菌曲线。结果甘草提取物对牙龈卟啉单胞菌、中间普氏菌、具核梭杆菌和伴放线放线杆菌的MIC值分别为1.50、1.50、0.75和1.50mg/mL,MBC值分别为6、3、3和3mg/mL。当甘草提取物达到对四种细菌的MBC值时,对于牙龈卟啉单胞菌、中间普氏菌、伴放线放线杆菌可在2h后可达到杀菌效果,对于具核梭杆菌可在4h后达到杀菌效果。结论甘草提取物对以上四种牙周常见致病菌具有良好的抑菌及杀菌作用。     

野生蓝莓提取物对四种致病菌的抑制作用

本研究选用中国野生蓝莓,研究了其提取物对铜绿假单胞菌、单增李斯特菌、金黄色葡萄球菌与副溶血性弧菌等四种致病菌的抑制作用,分别采用试管二倍稀释法和平板涂布法测定了野生蓝莓提取物的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。结果表明,野生蓝莓提取物对四种致病菌均有一定的抑制作用,对铜绿假单胞菌、单增李斯特菌、金黄色葡萄球菌与副溶血性弧菌的MIC分别为62.5、250、500 mg/m L与31.25 mg/m L,MBC分别为250、250、500与125 mg/m L。本研究首次报道了中国野生蓝莓对这四种致病菌的抑制作用,为中国野生蓝莓的开发和利用提供了依据。     

羟基酪醇抑菌活性及抑菌稳定性研究

本研究探究了羟基酪醇对大肠杆菌、金黄色葡萄球菌、铜绿假单胞杆菌和枯草芽孢杆菌等四种供试菌的抑菌活性及抑菌稳定性。采用试管半倍稀释法确定MIC和MBC,并探讨羟基酪醇对供试菌的生长和细胞膜完整性的影响以及在不同介质下的抑菌稳定性。结果表明,羟基酪醇对大肠杆菌、金黄色葡萄球菌、铜绿假单胞杆菌和枯草芽孢杆菌的MIC分别为0.625、0.625、1.250、2.500 mg/mL,MBC分别为1.250、1.250、2.500、5.000 mg/mL。与对照组相比,四种供试菌核酸和可溶性蛋白泄漏显著,细胞膜的完整性被破坏。在不同NaCl浓度下,羟基酪醇对枯草芽孢杆菌的抑菌活性稳定;在1.0%和2.0%NaCl浓度下,羟基酪醇对大肠杆菌和铜绿假单胞杆菌的抑菌活性稳定;在2.0%NaCl介质下低浓度的羟基酪醇对金黄色葡萄球菌的抑菌活性稳定,在0.5%、1.5%和2.0%NaCl介质下高浓度的羟基酪醇对金黄色葡萄球菌的抑菌活性稳定。在蔗糖介质中,羟基酪醇对四种供试菌的抑菌活性均不稳定。因此,羟基酪醇可以作为一种新型的防腐剂。     

瓦松总黄酮的提取及其抑菌效果

目的：提取瓦松总黄酮并对其总黄酮含量进行测定,进一步观察总黄酮的抑菌效果。方法：采用超声法提取瓦松总黄酮,以芦丁为标准品,用紫外分光光度法测总黄酮的含量;并参照NCCLS规范,用微量稀释法来测定总黄酮最小抑菌浓度（MIC）和最小杀菌浓度（MBC）。结果：测定标准曲线线性相关性良好,R2=0.999 2,线性范围在0.02~0.6 mg/mL。瓦松总黄酮对福氏志贺菌标准株抑菌效果最好,对部分临床分离金黄色葡萄球菌耐甲氧西林株（MRSA）、表皮葡萄球菌标准株、大肠埃希菌及其临床分离株、肺炎克雷伯菌标准株及其临床分离株抑菌效果较好,对金黄色葡萄球菌的抑菌效果最弱。瓦松水提物抑菌趋势与总黄酮一致性较差,总黄酮及水提物均无明显的MBC。结论：瓦松总黄酮及其水提物对本试验选取的菌株均有一定的抑制作用,且抑制作用较好。黄酮好于水提物,作用机制以抑制为主,而非直接杀菌。瓦松总黄酮具有较好的抑菌效果,在食品开发上有较高研究价值。     

竹叶提取物的体外抑菌及抗氧化活性的研究

本文用水提取竹叶有效成分,将提取液浓缩至含生药量约1.0 g/mL,经醇沉后取清液浓缩,再经石油醚、三氯甲烷、乙酸乙酯、正丁醇分步萃取,得不同极性的各部分提取物。以金黄色葡萄球菌和大肠杆菌为供试菌,采用抑菌圈法(琼脂扩散法)和最低抑菌浓度(MIC)法测定其抑菌效果。结果显示,石油醚、三氯甲烷、乙酸乙酯部分均表现抑菌活性。各供试样对两种菌的抑菌圈直径达9.8～18.4 mm,最低抑菌浓度分别为1.25 mg/mL2,.50 mg/mL和5.00 mg/mL。最后采用亚硝基红盐-Co2+褪色法研究了竹叶提取物对.OH的清除作用,结果表明三氯甲烷和乙酸乙酯部分萃取物的抗氧化性明显优于水提物,其中乙酸乙酯部分萃取物的IC50值为1.06 mg/mL。     

竹荪提取物对食源性细菌的抑菌特性研究

利用4种方法获得棘托竹荪和长裙竹荪的提取物,以5种食源性致病细菌单增李斯特菌、金黄色葡萄球菌、肠炎沙门菌、大肠埃希菌O157H7、副溶血性弧菌为供试菌,比较其MIC(最低抑菌浓度)和MBC(最低杀菌浓度)。超声波辅助破碎竹荪干粉,制取水、乙醇和石油醚为提取介质的浸提物以及竹荪挥发油,利用液体培养基连续稀释法对5种供试菌进行抑菌实验。所有提取物对供试菌都具有抑菌活性;长裙竹荪提取物的综合抑菌能力高于棘托竹荪提取物;水提物和挥发油的抑菌效果最好;2种竹荪提取物对革兰阴性菌和革兰阳性菌的抑菌作用存在互补效应。竹荪提取物对5种食源性细菌的生长有较好的抑制作用,可应用2种竹荪的提取物复配,开发天然食品防腐剂。     

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.     

In vitro antibacterial activity of laboratory grown culture of Spirulina platensis

The hexane, ethyl acetate, dichloromethane, methanol extracts and spent media (extracellular substances) were tested in vitro for their antibacterial activity for which one Gram-positive bacterium (Staphylococcus aureus) and four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumoniae) were used as test organisms. The methanol extract showed more potent activity than other organic extracts, spent medium of the culture exhibited little activity against E. coli only. No inhibitory effect was found against Klebsiella pneumoniae.The broth microdilution assay gave minimum inhibitory concentrations (MIC) values ranging from 1 to 512 μg/ml. The MIC of methanol extract against S. aureus and E. coli were 128 μg/ml and 256 μg/ml, respectively.     

Antibacterial abietane-type diterpenoid, taxodone from Metasequoia glyptostroboides Miki ex Hu

In an attempt to isolate bioactive constituents, ethyl acetate cone extract of Metasequoia glyptostroboides was subjected to a column chromatographic analysis that resulted in isolation of an abietane-type diterpenoid, taxodone. Its structure was elucidated by spectroscopic means. Further, taxodone showed potential antibacterial effect as diameters of zones of inhibition against foodborne pathogenic bacteria, such as Listeria monocytogenes ATCC 19166, Salmonella typhimurium KCTC 2515, S. enteritidis KCTC 2021, Escherichia coli ATCC 8739, E. coli O157:H7 ATCC 43888, Enterobacter aerogenes KCTC 2190, Staphylococcus aureus ATCC 6538 and S. aureus KCTC 1916, were found in the range of 9.4 to 14.2 mm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of taxodone against the employed bacterial pathogens were found in the range of 250 to 1000 and 250 to less than 2000 microg/ml, respectively. Also the compound had a strong antibacterial effect on the viable counts of the tested bacteria. These findings indicate that the bioactive compound taxodone present in M. glyptostroboides could be used as an antibacterial agent in food industry to inhibit the growth of certain important foodborne pathogens.     

In vitro antibacterial activity of Psidium guajava Linn. leaf extract on clinical isolates of multidrug resistant Staphylococcus aureus

In the present study, antibacterial activity of aqueous and organic extracts of Psidium guajava leaves was evaluated against multidrug resistant (MDR) clinical isolates of Staphylococcus aureus strains collected from hospitals in northern (Malabar region) Kerala. The strains which exhibited resistance against all the antibiotics tested was selected for antibacterial assays. Minimum inhibitory concentration (MIC) for methanolic and aqueous extracts was found to be 625 ug/ml and 7.5 mg/ml, respectively. Minimum bactericidal concentration (MBC) recorded for methanolic and aqueous extracts was 1.25 and 12.5 mg/ml, respectively. Methanolic extract at minimum bactericidal concentration inhibited the growth of MDR strain by 80%. Time-kill assay revealed that methanolic extract (4 mg/ml) killed MDR bacteria within 10 hr. Total polypeptide profiling of bacterial cultures by SDS-PAGE indicated a high degree of protein degradative activity of the extract. Finally, a human RBC based haemolytic assay showed absence of haemolysis even at concentrations higher than that of MBC, advocating thereby its safety in therapeutic use.     

Comparative activity against pathogenic bacteria of the root,stem, and leaf of <Emphasis Type="Italic">Raphanus sativus</Emphasis> grown in India

Aqueous, methanol, ethyl acetate, and chloroform extracts of the root, stem, and leaf of Raphanus sativus were studied for antibacterial activity against food-borne and resistant pathogens. All extracts except the aqueous extracts had significant broad-spectrum inhibitory activity. The ethyl acetate extract of the root had the potent antibacterial activity, with a minimum inhibitory concentration (MIC) of 0.016–0.064 mg/ml and a minimum bactericidal concentration (MBC) of 0.016–0.512 mg/ml against health-damaging bacteria. This was followed by the ethyl acetate extracts of the leaf and stem with MICs of 0.064–0.256 and 0.128–0.256 mg/ml, respectively and MBCs of 0.128–2.05 and 0.256–2.05 mg/ml, respectively. The ethyl acetate extracts of the different parts of R. sativus retained their antibacterial activity after heat treatment at 100°C for 30 min, and their antibacterial activity was enhanced when pH was maintained in the acidic range. Hence this study, for the first time, demonstrated that the root, stem, and leaf of R. sativus had significant bactericidal effects against human pathogenic bacteria, justifying their traditional use as anti-infective agents in herbal medicines.     

土茯苓提取物抗细菌活性的研究

通过测定土茯苓提取物对革兰氏阳性菌和革兰氏阴性菌的抑菌活性,来更全面的评价和综合利用土茯苓资源,实验结果表明土苓955乙醇和乙酸乙酯的提取物抑菌范围广,服抑菌活性强,这两种提取物的MIC和MBC值显示了土茯苓作为抗细菌资源的可利用价值。     

10种中草药提取物体外抗铜绿假单胞菌作用研究

通过对粗糠柴等10种中草药采用80%乙醇室温下浸渍制备的提取物进行体外抗铜绿假单胞菌及其耐药菌活性研究,并采取药敏纸片法测定临床分离菌株的耐药性。结果表明:这10种中草药80%乙醇提取物中,粗糠柴的乙酸乙酯层对铜绿假单胞菌标准菌及其耐药菌的抑菌效果最好,其抑菌圈直径范围在10~17 mm之间,MIC范围在0.125~0.5 mg·mL~(-1)之间,MBC范围在0.5~1 mg·mL~(-1)之间;正丁醇层、水层的抑菌活性较乙酸乙酯层弱,石油醚层对铜绿假单胞菌没有效果。而小叶藤黄、滇南红厚壳、续随子的乙酸乙酯层,巴豆、罗汉松、肉桂醇提物对铜绿假单胞菌及其耐药菌株有较弱抗菌活性;滇南红厚壳的正丁醇层、续随子乙酸乙酯层以及大八角和郁金的醇提物对铜绿假单胞菌及其耐药菌株均无活性。从这些数据中可以得出,粗糠柴的乙酸乙酯层、正丁醇层和水层对铜绿假单胞菌及其耐药菌有较好的抑菌活性,尤以乙酸乙酯层活性最好,而粗糠柴的石油醚层没有活性。     

Antibacterial activity of ethanolic and aqueous extracts of Acacia aroma Gill. ex Hook et Arn

The purpose of the present study was to investigate the antibacterial activity of seven ethanolic extracts and three aqueous extracts from various parts (leaves, stems and flowers) of A. aroma against 163 strains of antibiotic multi-resistant bacteria. The disc diffusion assay was performed to evaluate antibacterial activity of the A. aroma crude extracts, against several Gram-positive bacteria (E. faecalis, S. aureus, coagulase-negative stahylococci, S. pyogenes, S. agalactiae, S. aureus ATCC 29213, E. faecalis ATCC 29212) and Gram-negative bacteria (E. coli., K. pneumoniae, P. mirabilis, E. cloacae, S. marcescens, M morganii, A. baumannii, P. aeruginosa, S. maltophilia, E. coli ATCC 35218, P. aeruginosa ATCC 27853, E. coli ATCC 25922). All ethanolic extracts showed activity against gram-positive bacteria. Among all obtained extracts, only leaf and flower fluid extracts showed activity against Gram-negative bacteria. Based on this bioassay, leaf fluid extracts tended to be the most potent, followed by flower fluid extracts. Minimal inhibitory concentration (MIC) values of extracts and antibiotics were comparatively determined by agar and broth dilution methods. Both extracts were active against S. aureus, coagulase-negative stahylococci, E. faecalis and E. faecium and all tested Gram-negative bacteria with MIC values from 0.067 to 0.308 mg/ml. In this study the minimal bactericidal concentration (MBC) values were identical or twice as high than the corresponding MIC for leaf extracts and four or eight times higher than MIC values for flower extracts. This may indicate a bactericidal effect. Stored extracts have similar antibacterial activity as recently obtained extracts. The A. aroma extracts of leaves and flowers may be useful as antibacterial agents against Gram- negative and Gram-positive antibiotic multi-resistant microorganisms.     

金樱子茎提取物体外抑菌活性研究

采用纸片扩散法和试管稀释法,研究金樱子茎不同溶剂粗提取物对临床常见病原细菌的抑菌活性。结果表明,金樱子茎水提取物对绿脓杆菌、痢疾杆菌、大肠杆菌、变形杆菌无抑菌活性;对伤寒杆菌的最低抑菌浓度（MIC）为20 mg（生药）/mL;对金黄色葡萄球菌的MIC为10 mg（生药）/mL。金樱子茎75%乙醇提取物对绿脓杆菌、伤寒杆菌、痢疾杆菌、大肠杆菌、变形杆菌无抑菌活性;对金黄色葡萄球菌MIC为10 mg（生药）/mL。金樱子茎乙酸乙酯、氯仿、石油醚提取物对绿脓杆菌、伤寒杆菌、痢疾杆菌、大肠杆菌、金黄色葡萄球菌、变形杆菌无抑菌活性。