新疆圆柏枝皮醇提物抗菌活性的测定

本文对新疆圆柏枝皮乙醇提取物的抑菌特性进行了研究，测试了提取物对食品中主要致病、致腐细菌的最低抑菌浓度和最低杀菌浓度、试验了提取成分对热、压力、紫外光和金属离子的稳定性，结果表明：新疆圆柏枝皮乙醇提取物对受试菌均有较低的最低抑菌浓度和最低杀菌浓度，分别为：枯草芽孢杆菌MIC 0．25％，MBC 0．5％；金黄色葡萄球菌MIC 0．125％，MBC 0．125％；大肠杆菌MIC 0．0625％，MBC 0．125％；苏云金杆菌MIC 0．125％，MBC 0．25％；普通变形杆菌MIC 0．0625％，MBC 0．125％，产气肠杆菌MIC 0．03125％，MBC 0．125％。抑菌成分对热、压力、紫外光及金属离子稳定。     

不同提取工艺对川桂叶挥发油抑菌活性的影响

采用水蒸气蒸馏法、同时蒸馏萃取法和有机溶剂提取-水蒸气蒸馏法从川桂叶中提取挥发油,以金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、酵母、曲霉、青霉等6种常见污染菌作为供试菌,通过体外抑菌实验研究了3种不同提取工艺对挥发油抑菌活性的影响.实验结果表明,川桂叶挥发油对6种供试菌都具有很强的抑制作用,其中对酵母菌的抑制作用最强.不同提取工艺对挥发油的抑菌活性有显著影响,同时蒸馏萃取法提取的挥发油抑菌活性最强,其最低抑菌浓度(MIC)和最低杀菌浓度(MBC)是:金黄色葡萄球菌、大肠杆菌和枯草芽孢杆菌MIC0.125%,MBC0.125%,酵母MIC 0.0625%,MBC 0.0625%,曲霉和青霉MIC 0.250%,MBC 0.250%.     

中草药提取物对沙门氏菌的抑菌效果研究

主要选用黄连、蒲公英、黄柏、半枝莲、黄芩、石榴皮、板蓝根、连翘、柴胡、丁香等十味中草药,采用煎煮法提取其有效成分,并对这十味中药提取物在体外对致病性沙门氏菌的抑菌效果进行了测定。实验结果表明:不同中药提取物对沙门氏菌有不同的抑制效果,其中黄连、石榴皮、黄柏三味中药的抑菌效果较好;测得其最小抑菌浓度(MIC)分别为0.0625、0.125、0.125g/mL;最小杀菌浓度(MBC)分别为0.125、0.25、0.25g/mL。经线性回归计算,50%抑制时的有效浓度(EC50)分别为0.1414、0.3289、0.3598g/mL。     

木芙蓉(Hibiscus mutabilis)叶提取物对大肠杆菌O1和金黄色葡萄球菌91053的外抗菌效果研究

研究不同浓度木芙蓉(Hibiscus mutabilis)叶提取物对大肠杆菌(E.coliO1)和金黄色葡萄球菌(Staphylococcus aureus 91053)的体外抗菌效果.利用二倍稀释法和涂布平板法,确定提取物对两种菌种的最低抑菌浓度(MIC)和最低杀菌浓度(MBC),并绘制杀菌曲线.结果为:提取物对大肠杆菌的MIC和MBC浓度均为0.25 g/mL,8、4、2、1 MIC浓度的木芙蓉叶提取物分别在第6、14、18h能完全杀灭细菌该菌;提取物对金黄色葡萄球菌的MIC和MBC浓度均为0.5g/mL,4、2、1 MIC浓度的木芙蓉叶提取物对金黄色葡萄球菌的杀菌效果更佳,分别能在第6、10、14 h完全杀灭该菌.木芙蓉叶提取物对大肠杆菌和金黄色葡萄球菌均具明显的杀菌效果.     

广藿香挥发油的提取及抑菌活性成分稳定性的研究

以水蒸汽蒸馏法从广藿香中提取挥发油,采用正交试验法,研究了乙醇浓度、浸泡温度及提取时间对出油量的影响.确定了最佳的提取条件:70%乙醇,50℃浸泡,提取9 h.对挥发油的抑菌性能进行了研究,结果表明,该挥发油在强酸、重金属离子处理下不稳定,高温、紫外光处理对其稳定性基本没有影响.对金黄色葡萄球菌、绿脓杆菌和痢疾杆菌的最低抑菌浓度(MIC)分别为0.5 mg/mL、0.25 mg/mL和1 mg/mL,对三者的最低杀菌浓度(MBC)都是2 mg/mL.     

竹荪抑菌特性研究

本文对竹荪提取液的抑菌特性进行了研究,测试了竹荪对食品中主要致病致腐细菌的最低抑菌浓度和最低杀菌浓度、作用pH值范围,试验了提取成分对热和压力的稳定性,并选择有代表性的食品进行实物试验。结果发现:竹荪对8种受试菌均有较低的最低抑菌浓度和最低杀菌浓度,分别为:蜡样芽孢杆菌MIC5.0%、MBC5.0%,枯草芽孢杆菌MIC5.0%、MBC10.0%,金黄色葡萄球菌MIC2.5%、MBC2.5%,白色葡萄球菌MIC1.25%、MBC1.25%,大肠杆菌MIC5.0%、MBC5.0%,沙门氏菌MIC10.0%、MBC10.0%,志贺氏菌MIC2.5%、MBC5.0%和苏云金杆菌MIC2.5%、MBC2.5%。竹荪提取液发挥抑菌作用的pH值范围为5.0～8.5,抑菌成分对高温高压稳定,且实物试验效果良好。     

四种药用植物抑菌作用初探

本文对药用植物的抑菌作用进行了研究，测试了不同药用植物对细菌的抑菌圈大小、最低抑菌浓度及最低杀菌浓度，试验了提取成分对热的稳定性。结果发现：小檗色素对大肠杆菌抑菌作用最强，酸浆花萼色素对变彤杆菌抑菌作用最强，红景天浓缩液对枯草芽孢杆菌抑菌作用最强，小茼香浓缩液对四种待试菌无抑菌作用；小檗色素对四种待试菌的最低抑菌浓度和最低杀菌浓度分别为：枯草芽孢杆菌MIC2．5％、MBC5．0％，大肠杆菌MIC5．0％、MBC5．0％，金黄色葡萄球菌MIC2．5％、MBC5．0％，变形杆菌MICl．25％、MBC1．25％；酸浆花萼色素的最低抑菌浓度和最低杀菌浓度分别为：枯草芽孢杆菌MIC4．18％、MBC4．18％，大肠杆菌MIC8．35％、MBC8．35％，金黄色葡萄球菌MIC4．18％、MBC4．18％，变形杆菌MIC4．18％、MBC8．35％；红景天浓缩液的最低抑菌浓度和最低杀菌浓度分别为：枯草芽孢杆菌MIC2．09％、MBC4．18％，大肠杆菌MIC2．09％、MBC2．09％，金黄色葡萄球菌MIC8．35％、MBC8．35％，变形杆菌MIC4．18％、MBC8．35％。小檗色素、酸浆花萼色素和红景天浓缩液抑菌成分对高温稳定，抑菌机理尚待研究。     

阳荷不同极性部位体外抑菌活性研究

为研究阳荷的体外抑菌活性,采用70%乙醇回流提取阳荷粉末,依次用石油醚、乙酸乙酯、正丁醇萃取乙醇提取物,得到乙醇提取物、石油醚萃取物、乙酸乙酯萃取物、正丁醇萃取物和水萃取物;用滤纸片对乙醇提取物及不同极性萃取物进行抑菌活性测定,有抑菌活性的部位进一步测定其最低抑菌浓度(minimum inhibitory concentration,MIC)和最低杀菌浓度(minimum bactericidal concentration,MBC)。试验结果表明阳荷乙醇提取物、石油醚萃取物、乙酸乙酯萃取物和正丁醇萃取物,MIC值在3.125 mg/mL~12.5 mg/mL之间,MBC值为25 mg/mL;阳荷乙醇提取物、石油醚萃取物、乙酸乙酯萃取物、正丁醇萃取物和水萃取物对枯草芽孢杆菌有较强的抑菌效果,MIC值在3.125 mg/mL~12.5 mg/mL之间,MBC值为25 mg/mL;阳荷乙醇提取物和石油醚萃取物对大肠杆菌、肺炎克雷伯菌、粪肠球菌、铜绿假单胞菌和鲍曼不动杆菌均有抑菌效果;阳荷乙醇提取物、石油醚萃取物、乙酸乙酯萃取物、正丁醇萃取物和水萃取物对苏云金芽孢杆菌没有抑菌作用。阳荷对革兰氏阳性菌和革兰氏阴性菌具有广谱抑菌活性。     

新疆大沙枣果实抑菌作用研究

采用滤纸片法和管碟法分别研究了新疆大沙枣果实乙醇提取物对食品中主要致病、致腐菌的抑菌圈直径、最低抑菌浓度、最低杀菌浓度,并选择了有代表性的食品进行食物防腐实验。结果表明：该提取物有一定的抑菌活性,浓度越高其抑菌作用越强,且食物防腐实验效果良好。     

南五味子丙酮提取物对食品腐败细菌的抑制作用

目的:探讨南五味子丙酮提取物对食品腐败菌的抑制作用。方法:以金黄色葡萄球菌、铜绿假单胞菌、枯草芽孢杆菌等7种菌为供试菌,测定其抑菌圈直径、最低抑菌浓度(MIC)和最低杀菌浓度(MBC),并研究热处理、pH、紫外光对丙酮提取物抑菌活性的影响。结果:质量浓度为100mg/mL的丙酮提取物对供试菌的抑菌圈直径均大于12mm。丙酮提取物对供试菌的MIC值和MBC值:金黄色葡萄球菌100、150mg/mL,铜绿假单胞菌100、150mg/mL,大肠杆菌100、150mg/mL,枯草芽孢杆菌50、100mg/mL,蜡样芽孢杆菌50、100mg/mL,乙型副伤寒沙门氏菌100、150mg/mL,变形杆菌50、100mg/mL。121℃、30min热处理对该提取物抑菌活性无影响。当pH>4时对其抑菌活性有明显的影响。紫外光照射对其抑菌活性有一定的影响。结论:南五味子丙酮提取物对7种食品腐败细菌均有较好的抑制作用。     

生姜提取物的抑菌试验

实验用乙醚从生姜中提取其活性成分，探讨了其抑菌作用。结果表明，生姜提取物对微生物有明显抑制作用，其MIC值分别为金黄色的葡萄球、枯草杆菌、黑曲霉、青霉为0．25％，大肠杆菌0．5％，啤酒酵母菌0．125％。另外，生姜油经瞬时高温处理后，仍具有较强的抑菌作用。     

Short communication: effects of nonesterified fatty acids on lymphocyte function in dairy heifers

This in vitro study was performed to assess the effects of various concentrations of nonesterified fatty acids (NEFA) on lymphocyte function of heifers. Nine Holstein heifers were studied. Peripheral blood mononuclear cells were incubated with various concentrations of NEFA (0, 0.0625, 0.125, 0.25, 0.5, 1, and 2 mmol/L). The mixture of NEFA was represented by C16:0 (30%), C16:1 (5%), C18:0 (15%), C18:1 (45%), and C18:2 (5%). The DNA synthesis was diminished at concentrations of NEFA of 2, 1, and 0.5 mmol/L. The IgM secretion was inhibited at concentrations of NEFA of 2, 1, 0.5, and 0.25 mmol/L. Secretion of IFN-gamma was depressed at concentrations of NEFA of 2, 1, 0.5, 0.25, and 0.125 mmol/L. Increases of plasma NEFA might contribute to explain the higher incidence of infections observed in cows suffering from energy deficit.     

Antimicrobial effect of water extract of sumac (Rhus coriaria L.) on the growth of some food borne bacteria including pathogens

The antimicrobial effect of water extracts of sumac (Rhus coriaria L.) at concentrations of 0.1%, 0.5%, 1.0%, 2.5% and 5.0% (w/v), non-neutralized and after neutralization to pH 7.2+/-0.1, was studied on the growth of 12 bacterial strains (six Gram positive strains and six Gram negative strains), mostly food borne including pathogens. It was found to be effective against all the test organisms with Gram positive strains being more sensitive than Gram negative strains. Significant differences (P<0.01) were found among the bacteria and between the non-neutralized and neutralized extracts with non-neutralized being more effective against all the bacteria. The minimal inhibitory concentration (MIC) of the extract for each bacterial strain was studied by a gradient plate method. Among the Gram positive organisms, Bacillus species (Bacillus cereus, Bacillus megaterium, Bacillus subtilis, and Bacillus thuringiensis) were found to be the most sensitive showing MICs of 0.25-0.32% (after 24 h incubation) followed by Staphylococcus aureus (0.49%), while Listeria monocytogenes was found to be the least sensitive demonstrating a MIC of 0.67%. Of the Gram negative organisms, Salmonella enteritidis was found to be the most resistant with a MIC of 0.67% followed by Escherichia coli Type I, E. coli O157:H7, Proteus vulgaris and Hafnia alvei having MICs of 0.63%, 0.60%, 0.55% and 0.45%, respectively; whereas Citrobacter freundii was found to be the least resistant surviving up to 0.42%. Some loss of antimicrobial activity was, however, observed after incubation for 3 days. Bacteriostatic/bactericidal effects of sumac, as studied by enumerating survival by the viable count technique after 1 h direct contact of each microorganism with various concentrations of sumac extract, revealed a 4-5 log cycle reduction in Bacillus spp. and 2-3 log cycle reduction in other bacteria tested with 1.0% sumac extract.     

Antimicrobial activity of <Emphasis Type="Italic">Myagropsis myagroides</Emphasis> and interaction with food composition

Ethanol extract of Myagropsis myagroides (MMEE) has substantial antimicrobial activity against Gram-positive bacteria and some of the yeasts. The minimum inhibitory concentration (MIC) of MMEE ranged from 0.0625 to 0.125 mg/mL for Bacillus subtilis, Listeria monocytogenes, and Clostridium perfringens. Chloroform fraction obtained through liquid-liquid extraction possessed the strongest antimicrobial activity, and was separated by silica gel column chromatography. Among 22 of subfraction, CH4 showed the strongest activity (4–8 times MIC of the crude extract). The antimicrobial activity of CH4 to Staphylococcus aureus was reduced at high concentrations of starch, but the bactericidal effect of CH4 was maintained at 1 and 5% starch model media. The efficacy of CH4 against S. aureus diminished in the presence of >5% beef extract and >1% soybean oil. In acute toxicity test, no mortalities occurred in mice administered 5 g/kg body weight of MMEE over 2 weeks observation.     

凤尾兰乙醇提取物对几种果蔬致病菌的抑制作用研究

用60%乙醇(V/V)溶液提取凤尾兰叶,然后用滤纸片扩散法测定其对几种主要果蔬致病菌的抑制作用,用二倍稀释法确定提取液的最小抑菌浓度(MIC),并进一步研究了提取物对温度、紫外线的稳定性.结果表明,风尾兰60%乙醇提取液对蒜薹灰霉病菌、葱腐葡萄孢、柑橘绿霉和葡萄灰霉病菌有较明显的抑制效果,而对柑橘青霉没有抑制作用.提取液对蒜薹灰霉病菌、葱腐葡萄孢、柑桔绿霉和葡萄灰霉病菌的最小抑菌浓度分别为0.0625g/mL、 0.125g/mL、0.125g/mL和0.25g/mL.提取液浓度不同,对柑桔绿霉抑菌效果差异显著(P＜0.05),加热和紫外线照射对提取物的抑菌效果无显著影响(P＜0.05).     

南五味子乙醇提取物对食品腐败细菌的抑菌活性研究

目的:研究南五味子乙醇提取物的体外抑菌活性,以期为寻求新的天然食品防腐剂提供实验依据。方法:以抑菌圈直径、最低有效抑菌浓度等为指标,以金黄色葡萄球菌、乙型副伤寒沙门氏菌等7种食品腐败细菌作为供试菌,研究南五味子乙醇提取物的体外抗菌活性。结果:南五味子乙醇提取物对供试菌的抑菌圈直径均>20mm,且对革兰氏阳性细菌的抑制效果强于革兰氏阴性细菌。乙醇提取物对供试菌的MIC值和MBC值分别为金黄色葡萄球菌3.125,6.25mg/mL,蜡样芽孢杆菌1.562,3.125mg/mL,大肠杆菌25,25mg/mL,变形杆菌12.5,25mg/mL,枯草芽孢杆菌、乙型副伤寒沙门氏菌、宋内氏志贺氏菌、铜绿假单胞菌的MIC值和MBC值均为12.5mg/mL。提取物对供试菌的抑菌率随抑菌作用时间的延长,提取物浓度的增加而升高。提取物对蜡样芽孢杆菌抑菌能力大于苯甲酸钠和山梨酸钾;对金黄色葡萄球菌的抑菌能力与苯甲酸钠相同,稍差于山梨酸钾。结论:南五味子乙醇提取物对食品腐败细菌具有显著的抑菌活性,有望开发成天然食品防腐剂。     

树头发提取物抑菌作用研究

用树头发(pterula umbrinella Bres.)的乙醇水溶液提取物对三种细菌、两种酵母菌和两种霉菌进行抑菌研究。结果表明,树头发提取物对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、啤酒酵母、赤酵母、黑曲霉和桔青霉等都有抑制作用,对上述供试菌的最低抑菌浓度(MIC)分别为0.5%、0.5%、1.0%、3.0%、3.0%、2.5%、2.5%;热处理对提取物的抑菌效果无影响。