青天葵体外抑菌活性研究

目的:研究青天葵水提取液、醇提取液和水醇提取液对金黄色葡萄球菌、大肠杆菌、白色念珠菌、伤寒沙门菌、绿脓杆菌、黑曲霉菌6种菌株的抑菌效果。方法:制备青天葵3种提取液,采用试管两倍稀释法测定3种提取液对金黄色葡萄球菌等6种菌株的最低抑菌浓度(MIC)。结果:青天葵水提取液对伤寒沙门菌的抑菌作用较强(MIC为12.5%),对金黄色葡萄球菌、大肠杆菌、绿脓杆菌和黑曲霉菌的抑菌作用较弱(MIC为50%);醇提取液对伤寒沙门菌和绿脓杆菌都有很强的抑菌作用(MIC为6.25%),对金黄色葡萄球菌也有较强的抑菌活性(MIC为12.5%),对大肠杆菌的抑菌作用较弱(MIC为50%);水醇提取液的抑菌活性与醇提取液相当。结论:青天葵对金黄色葡萄球菌等6种菌株表现出不同程度的抑制活性。     

天然抗菌剂对5种致病菌的抑制作用研究

目的研究天然抗菌剂对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白念珠菌和黑曲霉的抑制作用。方法采用杯碟法和微孔板法测定天然抗菌剂对5种致病菌的抑菌圈大小、最小抑菌浓度(MIC)及对10株金黄色葡萄球菌的MIC。结果 1%天然抑菌剂对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白念珠菌和黑曲霉的抑菌圈分别是14.47 mm、10.67 mm、9.13 mm、28.13 mm、10.53 mm;天然抑菌剂对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白念珠菌和黑曲霉的MIC分别是0.08%、0.16%、0.63%、0.08%、0.16%,阳性对照(Sensiva SC50)对这5种菌的MIC分别是0.16%、0.16%、0.31%、0.16%、0.13%;天然抗菌的对10株金黄色葡萄球菌的MIC值分别为0.08%、0.06%、0.05%、0.09%、0.06%、0.07%、0.10%、0.06%、0.09%、0.07%。结论天然抗菌剂对这5种菌均有一定的抑制作用,对金黄色葡萄球菌和白念珠菌的抑制效果优于阳性对照,对大肠杆菌和黑曲霉的抑制效果与阳性药相当,对绿脓杆菌的效果略差于阳性药,对10株金黄色葡萄球菌均有较好的抑制作用。     

甘草根茎乙醇提取物抗菌活性研究

本实验采用琼脂扩散法和微量肉汤稀释法,研究了甘草根茎乙醇提取物对5种细菌(表皮葡萄球菌、金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌和绿脓杆菌)和2种真菌(白色念珠菌和黑曲霉)的抗菌活性。结果表明,甘草根茎乙醇提取物对革兰氏阳性菌非常敏感,而对革兰氏阴性菌和真菌不敏感,80%乙醇提取物对革兰氏阳性菌的MIC范围为0.156～0.312 mg·mL^-1,而10%乙醇提取物对革兰氏阳性菌的MIC范围为0.625～1.250 mg·mL^-1,表明甘草根茎抗菌活性成分在高浓度乙醇中溶解度较大,为临床上应用甘草根茎醇提物作为抗菌制剂提供了科学依据。     

不同分子量壳聚糖对五种常见菌的抑制作用研究

体外抑菌法研究了六种不同相对分子量的壳聚糖对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白色念珠菌、变形杆菌的抑菌活性,并对壳聚糖的抑菌机理做了探讨。     

不同分子量壳聚糖对五种常见茵的抑制作用研究

体外抑菌法研究了六种不同相对分子量的壳聚糖对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白色念珠菌、变形杆菌的抑菌活性,并对壳聚糖的抑菌机理做了探讨.     

响应面法优化苦丁茶熊果酸提取工艺及其抑菌活性研究

为优化苦丁茶熊果酸的提取工艺,并探讨其抑菌活性。在单因素试验基础上,通过响应面分析法,研究了液料比、提取温度、乙醇浓度对苦丁茶熊果酸得率的影响。以金黄色葡萄球菌、枯草芽孢杆菌、生孢梭菌、铜绿假单胞菌、大肠杆菌、白色念珠菌、黑曲霉为供试菌,探究了苦丁茶熊果酸的抑菌活性及最小抑菌浓度(Minimum inhibitory concentration,MIC)。结果表明,最优提取工艺为:液料比为17∶1(mL/g)、乙醇浓度为83%、提取温度83℃;抑菌实验表明,苦丁茶熊果酸对7种菌均有一定的抑制效果,对大肠杆菌、铜绿假单胞菌的MIC为6. 25 mg/mL,对生孢梭菌、金黄色葡萄球菌、枯草芽孢杆菌的MIC为12. 5 mg/mL,对白色念珠菌、黑曲霉的MIC为25 mg/mL。     

毛两面针挥发油化学成分及其生物活性

研究了毛两面针挥发油抑菌作用。抗菌实验结果表明,水蒸馏法提取的挥发油对金黄色葡萄球菌、白色念珠菌有明显的抑菌作用,乙醚提取的挥发油原液对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白色念珠菌有明显的抑菌作用。采用GC/MS分析了水蒸汽所得挥发油的化学成分,鉴定了20种物质,其中,主要成分是倍半萜。(-)-spathulenol、-γelemene和germacrene D等已被报道有抑菌作用的成分含量分别为12.53%、1.75%和1.44%。     

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。     

江西迷迭香精油的成分分析及抗氧化、抑菌活性研究

为了研究江西迷迭香精油的化学成分及抗氧化、抑菌活性,采用水蒸气蒸馏法提取迷迭香精油,利用气相色谱-质谱联用法(GC-MS)对迷迭香精油成分进行分析,通过对DPPH自由基、羟基自由基的清除活性和还原力来研究迷迭香精油的体外抗氧化活性;通过以枯草芽孢杆菌、金黄色葡萄球菌和大肠杆菌为供试菌,测定抑菌圈大小和最低抑菌浓度(MIC)来研究迷迭香精油的抑菌活性。实验结果表明,从迷迭香精油中鉴定出40种化学成分,占精油总量的99.46%,其主要化学成分有α-蒎烯(39.05%)和1,8-桉叶素(16.86%),其次是莰烯(4.22%)、D-柠檬烯(3.87%)、龙脑(3.74%)、β-石竹烯(3.11%)等,α-蒎烯的含量高于国内其他产地;迷迭香精油对DPPH、羟基自由基和还原力的半数清除率IC₅₀值分别为76.42、51.40和49.15μL/mL;精油对枯草芽孢杆菌、金黄色葡萄球菌和大肠杆菌的抑菌圈大小分别为14.40±0.66、11.41±0.19、11.70±0.27 mm,最低抑菌浓度(MIC)分别为2.50、10.00、10.00μL/mL,对枯草芽孢杆菌的抑制作用明显强于金黄色葡萄球菌和大肠杆菌。结果表明迷迭香精油具有较好的抗氧化、抑菌活性。     

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(19.90%),在所有成分中桉油精(12.39%)含量最高,其次为松油醇(8.70%)。(2)精油对金黄色葡萄球菌和大肠杆菌的抑菌圈直径分别为(22.57±1.68)mm和(15.36±0.71)mm。(3)精油对金黄色葡萄球菌和大肠杆菌的最小抑菌浓度分别为3.25和7.5μL/mL,最小杀菌浓度分别为7.5和15μL/mL。(4)当精油浓度为1.625和3.25μL/mL时,其分别能够延缓金黄色葡萄球菌和大肠杆菌的生长;当精油浓度为3.25和7.5μL/mL时,其能够完全抑制金黄色葡萄球菌的生长;当精油浓度为7.5和15μL/mL时,其能够完全抑制大肠杆菌的生长。(5)经精油处理之后的细菌,其相对电导率明显增大,且随精油浓度的增加而增大,同时其细胞膜发生了萎缩和破裂的现象。研究发现,莳萝蒿精油富含醇类和萜烯类等多种活性物质,对金黄色葡萄球菌和大肠杆菌具有良好的抑菌活性,且莳萝蒿精油能够改变细胞的膜结构,导致细菌中的内溶物发生泄漏,从而抑制细菌生长。     

Antibacterial and antifungal activity of ethanolic extracts from eleven spice plants

Eleven ethanolic extracts from spices of Melissa officinalis, Mentha piperita, Laurus nobilis, Rhus coriaria, Dianthus coryophyllum, Piper nigrum, Capsicum annum, Juniperus oxycedrus, Erica arborea, Colutea arborescens, and Cuminum cyminum collected from various regions of Turkey and local markets were assayed for the in vitro antibacterial activity against 3 Gram-positive (Bacillus subtilis, Staphylococcus aureus and S. epidermidis) and 2 Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), using agar dilution methods. In addition, their possible toxicity to Candida albicans and Aspergillus niger was determined, using both agar dilution and disc-diffusion methods. The minimum inhibition concentration (MIC) of the M. piperita, L. nobilis and J. oxycedrus ethanolic extracts was 5 mg/mL for all the microorganisms tested. P. aeruginosa was the most sensitive bacterial strain to P. nigrum and E. arborea extracts among both Gram-positive and Gram-negative bacteria tested with MIC of 5 mg/mL. The extracts of L. nobilis, D. coryophyllum, J. oxycedrus and C. arborescens showed higher inhibitory activity against the yeast C. albicans and the fungus A. niger than the standard antifungal nystatin.     

Synthesis and antibacterial activity of novel enolphosphate derivatives

A new class of enolphosphates derivatives, the 1-alkenyldiphosphates, was designed and a rapid and efficient synthesis for these compounds was developed. These new molecules showed interesting in vitro antibacterial activities (MIC) against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative pathogens including Pseudomonas aeruginosa and Escherichia coli.     

Chemical composition and antimicrobial activity of <Emphasis Type="Italic">Thymus pannonicus</Emphasis> All. (<Emphasis Type="Italic">Lamiaceae</Emphasis>) essential oil

This paper presents the results of a study on chemical composition and antimicrobial activity of Thymus pannonicus All. (Lamiaceae) essential oil from Vojvodina province (north of Serbia). The investigated oil was hydrodistilled from a flowering plant and analysed by GC and GC-MS. Fifty-three constituents were identified (>97% of total oil), with geranial (41.42%, w/w) and neral (29.61%, w/w) as the most prominent. The antimicrobial activity of the oil was evaluated using agar disc diffusion and broth microdilution method against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, two strains of Klebsiella pneumoniae and two strains of Candida albicans. The essential oil exhibited antimicrobial activity to varying degrees against all tested strains. The maximum activity of T. Pannonicus oil was observed against E. coli, S. aureus and both tested strains of C. Albicans (MIC = 50 μ/ml, each). Moderate activity was observed against P. aeruginosa and one of the tested strains of K. Pneumoniae (MIC = 200 μ/ml), while E. faecalis and the other strain of K. Pneumoniae expressed a higher degree of resistance (MIC > 200 μ/ml). This study confirms that essential oil of T. pannonicus possesses remarkable in vitro antimicrobial activity against several medicinally important pathogens. This is attributable to lemon-scented citral, a mixture of geranial and neral, which has well-documented antimicrobial activity against a range of bacteria and fungi.     

Study on the Composition and Physiological Activity of the Essential Oils and Extracts of Cinnamomum camphora Fruit

Supercritical carbon dioxide (SC-CO₂), hydrodistillation (HDO), ethanol extraction (EE), and petroleum ether extraction (PE) were used to extract the essential oil and extracts of Cinnamomum camphora fruit in this study. Gas chromatography-mass spectrometry was used to identify the volatile components of essential oils and extracts, and 63 compounds were identified. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and Ferric reducing ability of plasma (FRAP) assays and the inhibition experiment of bacteria and fungi (Staphylococcus aureus (S. aureus), Hay bacillus (H. bacillus), Escherichia coli (E. coli), Aspergillus niger (A. niger), Candida albicans (C. albicans)) showed these essential oils and extracts indicated antioxidant and antibacterial activities. S. aureus was the most sensitive to the essential oil (MIC=0.08 mg/ml). Combined with the Brine Shrimp Lethality Test (BSLT) experiment, HDO (LD₅₀=68.21 μg/ml) was considered to have the most potential natural preservative. Subsequently, the inhibitory mechanism of HDO on bacteria and fungi was explored through extracellular conductivity and SEM, and the possibility of HDO to preserve the freshness of bananas was verified through banana shelf-life experiments. The results suggested these essential oils and extracts of Cinnamomum camphora fruit indicated effectively inhibit the growth of microorganisms on the surface of bananas, extend the shelf-life, and have the potential to become a natural antiseptic ingredient.     

Chemical composition and antimicrobial,antioxidant, and anti-inflammatory activities of Lepidium sativum seed oil

Lepidium sativum (garden cress) seed oil was examined for its antimicrobial, antioxidant, and anti-inflammatory activities. The oil was obtained by hydrodistillation, where gas chromatography coupled with mass spectrometry that utilized to study its chemical composition. Microdilution method was used to test the antimicrobial effect of oil against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Klebsiella pneumoniae, and Candida albicans. The antioxidant activity was assessed by radical scavenging activity assay using 2,2-diphenyl-1-picrylhydrazyl radical. The major constituents found in the oil were 7,10-hexadecadienoic acid, 11-octadecenoic acid, 7,10,13-hexadecatrienoic acid, and behenic acid. The minimum inhibitory concentration (MIC) against all pathogens was 47.5 mg/ml, except for Salmonella enterica, which showed MIC of 90 mg/ml. The oil demonstrated antioxidant activity in a dose dependent pattern, with a half maximal inhibitory concentration (IC₅₀) value of 40 mg/ml, and exerted anti-inflammatory activity, wherein 21% protection was shown at a concentration of 300 μg/ml. Thus, L. sativum seed oil shows antimicrobial, antioxidant, and anti-inflammatory properties.     

Chemical constituents,antibacterial activity and mechanism of action of the essential oil from Cinnamomum cassia bark against four food-related bacteria

The majority of components of the essential oil from Cinnamomum cassia bark were identified by gas chromatography and mass spectrometry (GC-MS) in this study. The trans-cinnamaldehyde (68.52%) was found to be the major compound. The antibacterial activity of essential oil against four food-related bacteria was evaluated. The results showed it was stronger effect against Staphylococcus aureus with both the largest ZOI of 27.4 mm and the lowest minimum inhibitory concentration (MIC) of 2.5 mg/mL and minimum bactericidal concentration (MBC) of 5.0 mg/mL respectively. Postcontact effect (PCE) assay also confirmed the essential oil had a significant effect on the growth rate of surviving S. aureus and Escherichia coli. The mechanism against S. aureus and E. coli may be due to the increase in permeability of cell membranes, and the leakage of intracellular constituents based on cell permeability assay and electron microscopy observations.     

In vitro anti‐biofilm activity of Boswellia spp. oleogum resin essential oils

Aims: To evaluate the anti‐biofilm activity of the commercially available essential oils from two Boswellia species. Methods and Results: The susceptibility of staphylococcal and Candida albicans biofilms was determined by methyltiazotetrazolium (MTT) staining. At concentrations ranging from 217·3 μg ml^?1 (25% v/v) to 6·8 μg ml^?1 (0·75% v/v), the essential oil of Boswellia papyrifera showed considerable activity against both Staphylococcus epidermidis DSM 3269 and Staphylococcus aureus ATCC 29213 biofilms. The anti‐microbial efficacy of this oil against S. epidermidis RP62A biofilms was also tested using live/dead staining in combination with fluorescence microscopy, and we observed that the essential oil of B. papyrifera showed an evident anti‐biofilm effect and a prevention of adhesion at sub‐MIC concentrations. Boswellia rivae essential oil was very active against preformed C. albicans ATCC 10231 biofilms and inhibited the formation of C. albicans biofilms at a sub‐MIC concentration. Conclusions: Essential oils of Boswellia spp. could effectively inhibit the growth of biofilms of medical relevance. Significance and Impact of the Study: Boswellia spp. essential oils represent an interesting source of anti‐microbial agents in the development of new strategies to prevent and treat biofilms.     

Soluble laticifer proteins from Calotropis procera as an effective candidates for antimicrobial therapeutics

Calotropis procera is a latex-producing plant with plenty of pharmacologically active compounds. The principal motivation behind this study was to separate and characterize laticifer proteins to check their antimicrobial potential. Laticifer proteins were separated by gel filtration chromatography (GFC) and investigated using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). The SDS-PAGE assay detected proteins of molecular weights of 10 to 30 kDa but most of them were in the range of 25 to 30 kDa. The soluble laticifer proteins (SLPs) were tested against Gram-positive bacteria i.e., Streptococcus pyogenes and Staphylococcus aureus whereas Escherichia coli and Pseudomonas aeruginosa were tested as Gram-negative bacteria, we determined a profound anti-bacterial activity of these proteins. In addition, SLPs were also investigated against Candida albicans via the agar disc diffusion method which also showed significant anti-fungal activity. SLP exhibited antibacterial activity against P. aeruginosa, E. coli, and S. aureus with a minimum inhibitory concentration (MIC) of 2.5 mg/mL for each, while MIC was found at 0.625 mg/mL for S. pyogenes and 1.25 mg/mL for C. albicans. Moreover, enzymatic activity evaluation of SLP showed the proteolytic nature of these proteins, and this proteolytic activity was greatly enhanced after reduction which might be due to the presence of cysteine residues in the protein structure. The activity of the SLPs obtained from the latex of C. procera can be associated with the involvement of enzymes either proteases or, protease inhibitors and/or peptides.     

Synthesis and Biological Evaluation of Novel Carbazole Hybrids as Promising Antimicrobial Agents

Two series of carbazole analogs of 8‐methoxy‐N‐substituted‐9H‐carbazole‐3‐carboxamides (series 1) and carbazolyl substituted rhodanines (series 2) were synthesized through facile synthetic routes. All the final compounds from these two series were evaluated for their preliminary in vitro antifungal and antibacterial activity against four fungal (Candida albicans, Cryptococcus neoformans, Cryptococcus tropicalis and Aspergillus niger) and four bacterial (Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa) strains, respectively. Among the tested compounds, three compounds of series 1 displayed promising antifungal and antibacterial activity, especially against C. neoformans and S. aureus. In addition, one compound of series 1 displayed notable antimicrobial activity (MIC: 6.25 μg/mL) against clinical isolates of C. albicans and C. neoformans (MIC: 12.5 μg/mL). From the second series, four compounds exhibited significant antifungal and antibacterial activity, especially against C. neoformans and S. aureus. The most active compound of series 2 displayed a prominent antimicrobial activity against C. neoformans (MIC: 3.125 μg/mL) and S. aureus (MIC: 1.56 μg/mL), respectively.