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。     

湘西虎杖抑菌活性成分提取研究

对湘西虎杖抑菌活性物提取条件进行研究,通过抑菌实验得到最佳提取条件为90%乙醇、60℃、3 h,该条件下的提取物对细菌生长的抑制活性最强,但对酵母菌无明显的效果,对金黄色葡萄球菌、大肠杆菌、痢疾杆菌的最小抑菌浓度（MIC）为0.25 g/mL～0.5 g/mL.提取物经85℃、100℃,15 min或pH 2～8处理后仍具有较强的抑菌活性.     

小羽贯众提取物抗菌活性的初步研究

目的：比较小羽贯众根状茎和叶提取物体外抑菌活性。方法：牛津杯法和96孔板法,通过测定抑菌圈大小、最小抑菌浓度（MIC）和最小杀菌浓度（MBC）,比较小羽贯众根状茎和叶提取物分别对10种常见细菌的抑制作用,以及不同产地抑菌效果的比较。结果：小羽贯众的根状茎和叶的提取物对10种常见的细菌均表现出较强的抑菌活性,肺炎克雷伯氏菌对提取物最敏感。结论：小羽贯众提取物作为一种天然的抗菌物质,具有广谱抗菌效果,有较高的应用潜力和开发前景。     

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。     

蓝莓提取物对产超广谱β-内酰胺酶肺炎克雷伯菌的抑菌活性

【背景】随着细菌耐药性的增强,产超广谱β-内酰胺酶肺炎克雷伯菌的出现严重危害食品安全和人体健康。蓝莓中含有丰富的多酚和花青素,是天然抗菌材料的优选。【目的】分析蓝莓提取物对3株产超广谱β-内酰胺酶肺炎克雷伯菌的抑制活性及作用机制,并以牛乳为样品检测食品基质对蓝莓提取物抑菌活性的影响。【方法】利用甲醇制备巴尔德温和黑珍珠蓝莓提取物并检测提取物中总酚和花青素含量,利用纸片扩散法检测肺炎克雷伯菌的耐药性,利用最小抑菌浓度(minimum inhibitory concentration,MIC)、最小杀菌浓度(minimum bactericidal concentration,MBC)和生长曲线研究蓝莓提取物的抗菌活性,通过共聚焦激光扫描显微镜观察蓝莓提取物对细胞膜完整性的影响,并检测其在牛乳中的抑菌活性。【结果】巴尔德温和黑珍珠蓝莓提取物中的总酚含量分别为2.3 mg/g和3.5 mg/g,花青素含量分别为67.5 mg/100 g和92.5 mg/100 g。两种蓝莓提取物对肺炎克雷伯菌KP106、KP305和KP408的MIC均为25mg/mL,MBC均为50mg/mL。生长曲线表明...     

博落回不同部位提取物对大肠菌群的抑菌作用研究

研究了博落回提取物对大肠菌群的抑制作用。本实验以大肠杆菌、产气肠杆菌、阴沟肠杆菌为指示菌,采用牛津杯法筛选对三种指示菌有最佳抑制作用的博落回组织粗提物;对抑菌效果好的粗提物依次用石油醚、乙酸乙酯、正丁醇进行萃取,采用滤纸片法筛选出抑菌活性最高的萃取物,并测定其最小抑制浓度和最小杀菌浓度。实验结果表明博落回不同部位粗提物有抑制指示菌的活性,其中以博落回根部提取物的抑菌活性最佳;根部萃取物抑菌实验结果表明正丁醇萃取物对三种指示菌均有较好的抑制效果,抑菌圈直径均在12 mm以上,远高于粗提物,对大肠杆菌,其最小抑制浓度和最小杀菌浓度分别为400、600μg/m L,对产气肠杆菌与阴沟肠杆菌,其最小抑制浓度均为500μg/m L,最小杀菌浓度均为700μg/m L。博落回根部提取物对上述三种指示菌均有抑制作用,尤其以正丁醇萃取物的抑菌效果最佳。     

紫穗槐种子提取物的抑菌活性研究

目的研究紫穗槐种子提取物的抑菌活性。方法将紫穗槐种子乙醇提取物分别通过石油醚、乙酸乙酯和正丁醇萃取,选择金黄色葡萄球菌和肺炎克雷伯杆菌为供试菌,采用试管二倍稀释法测定紫穗槐种子提取物的最小抑菌浓度（MIC）和最小杀菌浓度（MBC）,涂布平板法绘制杀菌曲线,电镜下观察药物对细菌超微结构的影响。结果紫穗槐种子提取物经乙酸乙酯萃取后对供试菌抑制作用较强,其中对金黄色葡萄球菌的MIC和MBC分别为2．5、5．0mg／mL;对肺炎克雷伯杆菌的MIC和MBC分别为5．0、10．0mg／mL;杀菌曲线结果表明,药物对供试菌的抑制作用存在浓度和时间依赖性;电镜结果说明,药物的作用可能与破坏菌体细胞壁、改变细胞膜通透性有关。结论紫穗槐种子提取物具有显著的抗菌活性。     

黄花草木樨提取物抑菌活性初探

采用离体和活体试验方法分别测定了黄花草木樨不同溶剂提取物对12种植物病原真菌的抑菌活性.结果表明:各溶剂提取物对12种植物病原真菌均具有不同程度的抑菌活性,其中以乙酸乙酯提取物的抑菌活性最高,对油菜菌核病菌、玉米大斑病菌和白菜黑斑病菌抑制菌丝生长的EC50分别为0.62、0.83、0.64g/L,对稻瘟病菌和玉米大斑病菌抑制孢子萌发的EC50分别为0.67、0.97g/L.离体组织法测定表明其乙酸乙酯提取物对番茄灰霉病菌具有较高的保护和治疗作用,在浓度为5.0g/L时,防治效果分别为75.41%和59.18%(6d).活体试验表明乙酸乙酯提取物对小麦白粉病和小麦条锈病也有一定的保护作用,在浓度为10.0g/L时,防治效果分别为73.39%和63.27%.     

家蝇幼虫分泌物抗菌肽的生化特性初步研究

研究了不同温度、蛋白酶及反复冻溶对家蝇 Musca domestica 幼虫活体浸泡法获得的分泌物抗菌肽抗菌活性的影响;并检测其凝血效应;试管稀释法测定其最低抑菌浓度（MIC）、最低杀菌浓度（MBC）;SDS-PAGE分析其分子量范围。结果表明,该抗菌肽具有较强的热稳定性、酶稳定性及较强抗菌活性的特性,无凝血作用。对大肠埃希菌的最低抑菌浓度为37 μg/mL、最低杀菌浓度为75 μg/mL;分子量约10 kD。     

金银花和苦丁茶多糖提取物抗菌活性研究

从金银花和苦丁茶中提取水溶性多糖,利用圆形纸片法对7种常见的食品腐败菌进行抗菌试验。结果表明:金银花和苦丁茶多糖提取物都具有一定程度的抗细菌与抗真菌活性,抗细菌活性比抗真菌活性强;苦丁茶多糖提取物对金黄色葡萄球菌的最低抑菌浓度为5mg/ml。     

Evaluation of antimicrobial activity of certain Chinese plants used in folkloric medicine

Six selected plants, belonging to 3 families from Nanjing of China, were extracted with the solvent 95% (v/v) ethanol to yield 11 extracts. The extracts were evaluated for their effects on the growth of eight clinical bacteria, two fungi and one yeast using a modified agar diffusion method. The results showed that the majority of the extracts investigated showed greater activities against the Gram-positive bacteria than against the Gram-negative bacteria, the fungi and the yeast. The strongest antimicrobial activity was exhibited by the stem extracts of Mahonia fortunei against multiresistant Staphylococcus aureus strains, followed by the stem extracts of Mahonia bealei, while Bacillus thuringiensis was the most sensitive to all extracts.     

Antimicrobial activity of essential oils and other plant extracts

The antimicrobial activity of plant oils and extracts has been recognized for many years. However, few investigations have compared large numbers of oils and extracts using methods that are directly comparable. In the present study, 52 plant oils and extracts were investigated for activity against Acinetobacter baumanii, Aeromonas veronii biogroup sobria, Candida albicans, Enterococcus faecalis, Escherichia col, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serotype typhimurium, Serratia marcescens and Staphylococcus aureus, using an agar dilution method. Lemongrass, oregano and bay inhibited all organisms at concentrations of < or = 2.0% (v/v). Six oils did not inhibit any organisms at the highest concentration, which was 2.0% (v/v) oil for apricot kernel, evening primrose, macadamia, pumpkin, sage and sweet almond. Variable activity was recorded for the remaining oils. Twenty of the plant oils and extracts were investigated, using a broth microdilution method, for activity against C. albicans, Staph. aureus and E. coli. The lowest minimum inhibitory concentrations were 0.03% (v/v) thyme oil against C. albicans and E. coli and 0.008% (v/v) vetiver oil against Staph. aureus. These results support the notion that plant essential oils and extracts may have a role as pharmaceuticals and preservatives.     

Synthesis, antibacterial activities and molecular docking studies of Schiff bases derived from N-(2/4-benzaldehyde-amino) phenyl-N'-phenyl-thiourea

A series of novel Schiff base derivatives have been designed and synthesized, and their biological activities were also evaluated as potential inhibitors of FabH. These compounds were assayed for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Compounds with potent antibacterial activities were tested for their E. coli FabH inhibitory activity. Compound 3v showed the most potent antibacterial activity with MIC of 1.56-6.25 μg/mL against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with IC(50) of 4.3 μM. Docking simulation was performed to position compound 3v into the E. coli FabH active site to determine the probable binding conformation.     

一株真菌拮抗细菌Z21的筛选与鉴定及其发酵条件优化

【背景】芽孢杆菌属的许多细菌具有抗逆性强、安全等特点,一直以来都是开发新型活性物质的研究热点。【目的】筛选对食品腐败真菌有抑制作用的细菌,将其开发为天然食品防腐剂。【方法】采用平板分离法、平板对峙法、抑制菌丝生长速率法从空气、竹子内生细菌中筛选真菌拮抗菌,通过形态、生理生化特征及16S rRNA基因序列分析等方法对其进行鉴定,利用正交试验确定其最优生长条件。【结果】筛选到一株对6种常见霉菌均有较强抑制作用的细菌Z21。Z21与甲基营养型芽孢杆菌(Bacillusmethylotrophicus strain CBMB205~T)的相似性最高,且形态特征和生理生化特征与CBMB205~T菌株基本相符。Z21最佳发酵培养基配方和培养条件分别为:葡萄糖20.0 g/L、NaNO_3 20.0 g/L、MgSO_4 3.0 g/L,培养温度为32°C,培养时间为48 h。【结论】Z21为甲基营养型芽孢杆菌(Bacillus methylotrophicus),对黑曲霉、康氏木霉、绿色木霉、少根根霉、易脆毛霉、赭绿青霉的生长具有较强的抑制作用且抑菌效果稳定,为广谱真菌拮抗菌。     

Evaluation of antimicrobial activity of the lichens Lasallia pustulata, Parmelia sulcata, Umbilicaria crustulosa, and Umbilicaria cylindrica

The antimicrobial properties of acetone, methanol, and aqueous extracts of the lichens Lasallia pustulata, Parmelia sulcata, Umbilicaria crustulosa, and Umbilicaria cylindrica were studied comparatively in vitro. Antimicrobial activities of the extracts of different lichens were estimated by the disk diffusion test for Gram-positive bacteria, Gram-negative bacteria, and fungal organisms, as well as by determining the MIC (minimal inhibitory concentration). The obtained results showed that the acetone and methanol extracts of Lasallia pustulata, Parmelia sulcata, and Umbilicaria crustulosa manifest antibacterial activity against the majority of species of bacteria tested, in addition to selective antifungal activity. The MIC of lichen extracts was lowest (0.78 mg/ml) for the acetone extract of Lasallia pustulata against Bacillus mycoides. Aqueous extracts of all of the tested lichens were inactive. Extracts of the lichen Umbilicaria cylindrica manifested the weakest activity, inhibiting only three of the tested organisms.     

Evaluation of the medicinal potentials of the methanol extracts of the leaves and stems of Halleria lucida

The medicinal potentials of the methanol extracts of the leaves and stems of Halleria lucida (Scrophulariaceae) were evaluated by assessing their antibacterial and antioxidant properties in vitro using standard procedures. The antioxidant activities of methanol extract of the leaves as determined by the ABTS, DPPH, proanthocyanidins and total flavonoids were higher than that of the stem. On the other hand, the total phenols, the flavonoids and the FRAP contents of the stem were higher than that of the leaves. The extracts however showed poor activity against both Gram-positive and Gram-negative bacteria. The methanol extract of the stem showed activities against Bacillus cereus and Staphylococcus epidermidis at MIC of 1.0 mg/ml. The methanol extract of the leaves did not show activity against any of the organisms used in this study. This study has to some extent validated the medicinal potential of the leaves and stems of H. lucida.     

半枝莲黄酮的超声提取及其抗氧化活性

通过单因素和正交试验获得超声波辅助乙醇提取半枝莲黄酮的最佳工艺条件,考察了黄酮提取物对油脂的抗氧化活性及对羟基自由基的清除效果,并与常用的抗氧化剂作比较。结果表明,当乙醇体积分数为50%、料液比1∶30（g/mL）、超声提取时间25 min、浸泡温度65℃时为最佳条件,此时黄酮的得率为3.0%,且该提取物对羟基自由基清除效果随浓度的增大而升高,对油脂氧化有较强的抑制作用。     

Antimicrobial effect of oxidized cellulose salts

Antimicrobial properties of oxidized cellulose and its salts in linters (-L) and microsphere (-M) form (OKCEL H-L, OKCEL Zn-M, OKCEL ZnNa-L, OKCEL ZnNa-M and OKCEL Ag-L) were tested by a dilution method against a spectrum of microbial strains: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Bacillus licheniformis, Aspergillus niger, Penicillium chrysogenum, Rhizopus oryzae, Scopulariopsis brevicaulis, Candida albicans and Candida tropicalis. OKCEL Ag-L exhibited antimicrobial activity in the range 0.1-3.5% w/v against all the bacteria and fungi involved in this study. Strong inhibition by OKCEL ZnNa-M was observed for Staphylococcus epidermidis, Bacillus licheniformis, Rhizopus oryzae, Candida albicans and Candida tropicalis in the range 0.5-2.0% w/v. Antimicrobial effects of oxidized cellulose and its salts in textile form were investigated by a diffusion and dilution method against the spectrum of above-cited microbial strains extended by Clostridium perfringens. Generally, OKCEL Ag-T, OKCEL Zn-T and OKCEL H-T showed high antimicrobial activity against populations of Pseudomonas aeruginosa, Bacillus licheniformis and Staphylococcus epidermidis. OKCEL Zn-T was the only sample suppressing the growth of species.     

GC/MS and LC/MS analysis,and antioxidant and antimicrobial activities of various solvent extracts from Mirabilis jalapa tubers

The antioxidant and antimicrobial activities of various solvent extracts from Mirabilis jalapa tubers (MJT) were investigated using various in vitro assays. The total phenolic and flavonoid contents varied from 21.45 to 364.6 mg gallic acid equivalent (GAE)/g dried extract and 5.2 to 71.6 mg quercetin/g dried extract, respectively. Water extract of MJT was the most potent antioxidant in all assays used, followed by methanol extract. The five solvent extracts were screened for antibacterial and antifungal activities. Water extract was the most effective with minimum inhibitory concentration <200 μg/ml against Staphylococcus aureus, Micrococcus luteus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Bacillus cereus and Enterococcus faecalis. Only water extract showed antifungal activity against Aspergillus niger, Fusarium solani, Fusarium oxysporium and Fusarium granularium. GC/MS analysis of MJT dichloromethane and methanol extracts showed that oleic acid and β-sitosterol were, respectively, the major compounds. LC/MS analysis of the aqueous extract showed a high content of flavanol and flavonol compounds. Phenolic acids such as ferulic and caffeic acid were also detected.To our knowledge, this is the first report on the chemical composition, and antioxidant and antimicrobial activities of phenolic extracts from M. jalapa tubers (MJT). The results of the present work indicate that MJT extracts could be used as natural antioxidant and antimicrobial agents in the food preservation and human health.