香橼精油体外抗氧化及其抑菌活性研究

为了研究香橼精油的抗氧化性及对细菌、酵母和霉菌的抑菌活性,本文采用体外抗氧化法和琼脂平板扩散法,研究香橼精油总还原力,清除DPPH自由基、·OH自由基和H2O2能力,以及对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、酿酒酵母、黑曲霉的抑制作用。结果表明:香橼精油的抗氧化能力与质量浓度呈正相关,对DPPH自由基、·OH自由基(IC50值为0.32 mg/m L)和H2O2(IC50值为148μg/m L)均有一定的清除能力。香橼精油对霉菌的抑制作用明显强于酵母与细菌,其中对黑曲霉的抑制效果最显著(25.39±1.12)mm,对金黄色葡萄球菌抑制最弱(14.04±1.35)mm。最小抑菌浓度在0.31~1.25 mg/m L,且在p H5~7范围内、温度80、115、121℃及一定时间紫外线照射(20、40 min)影响下,对大肠杆菌和酿酒酵母仍保持较强的抑制作用。     

信阳茶树花精油的成分、抗氧化性及抑菌作用分析

为提高信阳茶树花综合利用价值,采用索氏抽提法提取茶树花精油,利用气相色谱-质谱法(GC-MS)对精油成分和含量进行分析,通过体外自由基清除试验评价其抗氧化能力,并通过抑菌圈法和最低抑菌浓度(MIC)试验测定其抑菌活性。结果表明:茶树花精油中共鉴定出18种挥发性成分,包括醇类、脂肪酸类和萜烯类等化合物,其中苯乙醇(26.09%)和棕榈酸(17.93%)相对含量较高;茶树花精油具有一定抗氧化能力,其对DPPH和ABTS+这2种自由基的IC50值分别为44.93 mg/mL和48.47 mg/mL;茶树花精油对金黄色葡萄球菌、大肠杆菌、酵母菌均有较明显抑制作用,其中对金黄色葡萄球菌抑制效果最强,抑菌圈直径为15.3±0.2 mm, MIC为10%。试验结果可为茶树花精油的开发应用提供理论依据。     

甜橙精油纳米乳液的制备及其抑菌作用研究

采用相转变点法制备甜橙精油纳米乳液和D-柠檬烯纳米乳液,采用抑菌圈法和最低抑菌浓度法研究甜橙精油纳米乳液及其主要成分D-柠檬烯纳米乳液对大肠杆菌(Escherichia coli)、枯草芽孢杆菌(Bacillus subtilis)、金黄色葡萄球菌(Staphylococcus aureus)和桔霉菌(Penicillium citrinum)的抑菌作用。结果表明,甜橙精油纳米乳液和D-柠檬烯纳米乳液均有较好的抑菌效果,且同等浓度的D-柠檬烯纳米乳抑菌效果比甜橙精油的抑菌效果好,14%甜橙精油纳米乳液对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌和桔青霉的抑菌圈直径直径分别为11.7、14.0、9.7和9.0 mm,而D-柠檬烯纳米乳液对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌和桔青霉的抑菌圈直径直径分别为19.0、23.7、13.0和12.0 mm。甜橙精油纳米乳液对枯草芽孢杆菌的抑菌作用最强,其最低抑菌浓度(MIC)约为7.7%,对金黄色葡萄球菌和桔青霉的抑菌作用较弱,其对这两种微生物的MIC均约为11%,对大肠杆菌的MIC介于7.7%~11%之间。甜橙精油和D-柠檬烯制成纳米乳液后均具有良好的抑菌作用,为纳米乳液在食品中的抑菌应用提供了理论依据。     

昆仑雪菊油树脂精油成分分析及抑菌活性

采用超临界CO2流体法萃取得到昆仑雪菊油树脂精油,用气相色谱-质谱联用(GC-MS)技术对其成分进行分离鉴定,结果表明:昆仑雪菊油树脂精油有84种化合物,主要成分为烯类(64.12%)、醇类(11.47%)、烷烃类(8.76%)、酸类(6.31%)、酯类(1.5%),占总化合物含量的92.16%。以抑菌圈和最低抑菌浓度MIC为考察指标,采用滤纸片法进行抑菌试验。发现昆仑雪菊油树脂精油对大肠杆菌、金黄色葡萄球菌、枯草杆菌、青霉、黑曲霉均有抑制作用。对大肠杆菌的最小抑菌浓度(MIC)值为25%,对金黄色葡萄球菌菌、枯草杆菌、青霉和黑曲霉的MIC值分别为50%、75%、50%和75%。     

柠檬草精油成分分析、抑菌性及对巨峰葡萄保鲜研究

采用中国西南地区的柠檬草,以水蒸气蒸馏法提取得到的柠檬草精油(lemongrass essential oil,LEO),通过气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)分析柠檬草精油的成分和相对含量;通过测定抑菌圈直径和最低抑菌浓度研究对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌的抑菌效果;研究不同浓度的柠檬草精油对新鲜采摘的巨峰葡萄产品品质和生理的影响,确定其保鲜作用。结果表明:当料液比达到1∶15(g/mL)时,出油量与得率达到最大,平均得率为0.91%。利用GC-MS分析柠檬草精油成分,其中有21种组分,主要成分为柠檬醛,占比为70.11%。柠檬草精油对3种供试菌均有较好抑制作用,对枯草芽孢杆菌、金黄色葡萄球菌和大肠杆菌抑菌圈大小分别为23.8、22.5 mm以及11.2 mm。其中对金黄色葡萄球菌和枯草芽孢杆菌的抑制效果较好,对金黄色葡萄球菌和枯草芽孢杆菌的最低抑菌浓度为0.1μL/mL,大肠杆菌的最低抑菌浓度为0.2μL/mL;与对照组相比,柠檬草精油处理能有效缓解可滴定酸、可溶性固形物含量和硬度的降低,减少烂果率和失重率,其中0.50%柠檬草精油处理组的保鲜效果明显好于其他处理组。由此可见,柠檬草精油具有抑菌和水果保鲜的作用。     

柠檬香蜂草精油化学成分的研究

分别采用微波水蒸气蒸馏法(MHD)和水蒸气蒸馏法(HD)提取得到了柠檬香蜂草精油,利用气相色谱-质谱(GC/MS)联用技术和保留指数比较法分析鉴定了该精油的化学成分.分析结果表明:两种方法所得精油的主要成分相同,均为柠檬醛,但是含量有所差异.从MHD法柠檬香蜂草精油中鉴定出28种成分,占精油总量的98.98％,主要成分为柠檬醛a(香叶醛)(50.42％)、柠檬醛b(橙花醛)(30.42％)、石竹烯氧化物(9.17％)和石竹烯(1.63％).从HD法柠檬香蜂草精油中鉴定出22种化学成分,占精油总量的93.68％,主要成分为柠檬醛a(香叶醛)(46.27％)、柠檬醛b(橙花醛)(28.21％)、石竹烯氧化物(5.97％)和石竹烯(3.28％).     

豆蔻精油的杀菌活性及其在肉食品中的应用

研究目的是调查豆蔻精油的杀菌活性及其在食品中的应用。本试验中,豆蔻精油对大肠杆菌、单核细胞增生李斯特和金黄色葡萄球菌呈显著的抗菌活性,最小抑制浓度(MIC)和最小杀菌浓度(MBC)均分别为0.05%和0.1%。对单核细胞增生李斯特菌的MIC和MBC为0.1%和0.2%,肠炎沙门氏菌MIC和MBC均为0.05%。此外,肉制品是人类主要食物和营养的重要来源。通过平板菌落计数法测定了豆蔻精油在猪肉、鸡肉、牛肉中对大肠杆菌生长的抑制作用,并且在猪肉中豆蔻精油对金黄色葡萄球菌也有显著的抑制作用。     

香樟精油的体外抑菌活性

采用抑菌圈实验和二倍稀释法研究了香樟精油对金黄色葡萄球菌的抑菌活性、最低抑菌浓度(MIC)。结果表明:香樟精油对金黄色葡萄球菌抑菌活性显著,当香樟精油的浓度大于12.5%时,可完全抑制金黄色葡萄球菌的生长。     

茶多酚、柠檬醛和肉桂醛对食源菌生物被膜的影响研究

研究茶多酚、柠檬醛、肉桂醛在亚抑菌浓度下对食源性金黄色葡萄球菌和肠炎沙门氏菌生物被膜形成能力的影响.采用二倍稀释法确定三种物质的最小抑菌浓度,在亚抑菌浓度下作用于10株金黄色葡萄球菌和10株肠炎沙门氏菌,用微孔板法检测两种细菌生物被膜形成情况.结果表明茶多酚、柠檬醛、肉桂醛在亚抑菌浓度下对金黄色葡萄球菌和肠炎沙门氏菌均有不同程度的抑制作用,差异有统计学意义(P＜0.05),且随着各物质浓度的加大抑制作用也增强,茶多酚对革兰氏阳性菌金黄色葡萄球菌成膜抑制能力比对革兰氏阴性菌肠炎沙门氏菌的成膜抑制能力要强,差异有统计学意义(P＜0.05).柠檬醛和肉桂醛对两种不同细菌的成膜抑制能力没有差异.     

黔产青花椒精油成分分析及抑菌、抗氧化活性研究

以黔产青花椒为原料，采用水蒸气蒸馏法提取精油，运用气相色谱-质谱法（GC-MS）分析化学成分，并以大肠杆菌、耻垢分岐杆菌、铜绿假单胞菌、金黄色葡萄球菌为试验菌种评价抑菌活性和以DPPH自由基清除能力为指标评价精油的抗氧化活性。结果表明，从黔产青花椒精油中共鉴定出10个成分，以烯烃类、醇类、酮类为主，占精油总量的99.51%，其中相对含量高于3%的分别为β-芳樟醇（91.10%）、D-柠檬烯（3.12%）；精油对耻垢分岐杆菌的最小抑菌浓度（MIC）为4%，对大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌的最小抑菌浓度（MIC）为8%。精油的抗氧化活性随着青花椒精油浓度的增加而逐渐升高，当浓度在52.1～884.2 mg/mL范围内时，最高清除率为92.747%。水蒸气蒸馏提取的青花椒精油中β-芳樟醇含量最高，具有较好的抑菌作用和抗氧化活性。     

Lavender,tea tree and lemon oils as antimicrobials in washing liquids and soft body balms

The aim of this study was to evaluate the antimicrobial activity of commercial essential oils: lavender, tea tree and lemon, antimicrobials in washing liquid and O/W soft body balm. The inhibition efficacy of essential oils in washing liquid (1% alone or in mixtures), in soft body balm (0.5% alone), as well as combined with the synthetic preservative DMDM hydantoin and 3‐iodo‐2‐propynyl butyl carbamate mixture (0.1 and 0.3%), was tested against S. aureus ATCC 6538, P. aeruginosa ATCC 9027, Candida sp. ?OCK 0008 and A. niger ATCC 16404 in compliance with the European Pharmacopoeia standards. The components of the system preserving soft body balm were supplemented with a solubilizer. Washing liquids containing only essential oils met Criterion A E.P. only for S. aureus, Candida sp. and A. niger. In soft body balm formulations, oils at a concentration of 0.5% did not reveal any preserving activity. The introduction of a solubilizer to a system containing 0.5% tea tree oil led to a substantial increase in the bacteriostatic activity of the formulation, but did not significantly affect its fungistatic properties. A combination of 0.5% tea tree oil, 5% solubilizer and 0.3% synthetic preservative ensured the microbiological stability of soft body balm in accordance with Criterion A E.P.     

Efficacy of plant essential oils against foodborne pathogens and spoilage bacteria associated with ready-to-eat vegetables: antimicrobial and sensory screening

The objectives of this study were to evaluate the antimicrobial activity of plant essential oils (EOs) against foodborne pathogens and key spoilage bacteria pertinent to ready-to-eat vegetables and to screen the selected EOs for sensory acceptability. The EOs basil, caraway, fennel, lemon balm, marjoram, nutmeg, oregano, parsley, rosemary, sage, and thyme were evaluated. The bacteria evaluated were Listeria spp., Staphylococcus aureus, Lactobacillus spp., Bacillus cereus, Salmonella, Enterobacter spp., Escherichia coli, and Pseudomonas spp. Quantitative antimicrobial analyses were performed using an absorbance-based microplate assay. Efficacy was compared using MIC, the half maximum inhibitory concentration, and the increase in lag phase. Generally, gram-positive bacteria were more sensitive to EOs than were gram-negative bacteria, and Listeria monocytogenes strains were among the most sensitive. Of the spoilage organisms, Pseudomonas spp. were the most resistant. Oregano and thyme EOs had the highest activity against all the tested bacteria. Marjoram and basil EOs had selectively high activity against B. cereus, Enterobacter aerogenes, E. coli, and Salmonella, and lemon balm and sage EOs had adequate activity against L. monocytogenes and S. aureus. Within bacterial species, EO efficacy was dependent on strain and in some cases the origin of the strain. On a carrot model product, basil, lemon balm, marjoram, oregano, and thyme EOs were deemed organoleptically acceptable, but only oregano and marjoram EOs were deemed acceptable for lettuce. Selected EOs may be useful as natural and safe additives for promoting the safety and quality of ready-to-eat vegetables.     

柑橘精油的抑菌性及D-柠檬烯在面包的初步应用研究

研究商品柑橘精油及D-柠檬烯对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、酵母、毛霉、青霉的抑菌性,并对D-柠檬烯在面包上做初步应用研究。试验结果表明:样品以液体作用方式的抑菌大小为D-柠檬烯>柠檬油>柚油>橙油;以气体作用方式时只有D-柠檬烯对酵母、青霉能形成抑菌圈;D-柠檬烯应用于面包时,其气体抑菌效果较好。     

河南产白蒿精油的化学成分分析及抑菌活性研究

为寻找新型、有效、安全的抗菌药物,采用水蒸气蒸馏法从中国河南产白蒿植物中提取精油,采用红外光谱和气相色谱-质谱联用技术对精油成分进行分析。结果表明,共鉴定出26种成分,占精油总含量的85.05%。主要成分有氧化石竹烯(15.24%)、镰叶芹醇(14.34%)、大根香叶三烯-1-醇(8.90%)、桉油烯醇(6.61%)、棕榈酸(5.72%)、α-毕橙茄醇(5.19%)等。采用滤纸片法对白蒿精油的抑菌活性进行测定,平板涂布法测定其最低抑菌浓度。该精油对4种受试细菌的抗性差异显著,其中对枯草芽孢杆菌抑制活性最强,而对蜡样芽孢杆菌的抑制活性较弱。精油对枯草芽孢杆菌、四联球菌、大肠杆菌、蜡样芽孢杆菌的最低抑制浓度(minimum inhibitory concentration,MIC)分别为2.5、5、5、10μL/mL。因此,白蒿精油可作为一种潜在的天然抗菌剂。     

Chemical composition and antimicrobial activity of Rosmarinus officinalis L. essential oil obtained via supercritical fluid extraction

The chemical composition and antimicrobial activity of essential oil-rich fractions obtained by supercritical CO2 extraction from Rosmarinus officinalis L. were investigated. Gas chromatography-mass spectroscopy analysis of these fractions resulted in the identification of 33 compounds of the essential oil. The main components of these fractions were alpha-pinene, 1,8-cineole, camphor, verbenone, and borneol, constituting ca. 80% of the total oil. The antimicrobial activity was investigated by the disc diffusion and broth dilution methods against six microbial species, including gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), a yeast (Candida albicans), and a fungus (Aspergillus niger). All of the essential oil-rich fractions obtained showed antimicrobial activity against all of the microorganisms tested, with inhibition zones and minimal bactericidal and fungicidal concentration values in the range of 17 to 33 mm and 2.25 to 0.25 mg/ml, respectively. The most active fraction was the one obtained in experiment 4 (4% ethanol as modifier; extraction pressure, 25 MPa; extraction temperature, 60 degrees C). S. aureus was found to be the most sensitive bacteria to the rosemary extracts, whereas the least susceptible was A. niger. alpha-Pinene, 1,8-cineole, camphor, verbenone, and borneol standards also showed antimicrobial activity against all the microorganisms tested, borneol being the most effective followed by camphor and verbenone. In that way, it was confirmed that essential oil from experiment 4, with the best antimicrobial activity, presented the highest quantity of camphor, borneol, and verbenone.     

樟树精油及其单体抗白色念珠菌活性及安全性研究

为探究樟树精油及其单体抗白色念珠菌活性及安全性,本研究通过纸片法和微量肉汤稀释法测定了樟树精油、葡萄柚精油、柠檬精油、薰衣草精油抗白色念珠菌活性,同时对樟树精油进行GC-MS挥发性成分鉴定,进一步分析樟树精油主要化学成分对白色念珠菌的抑菌活性,最后观察樟树精油及其单体对豚鼠皮肤刺激和小鼠血管收缩性影响。结果表明,樟树精油抗白色念珠菌活性强于葡萄柚、柠檬、薰衣草精油;樟树精油抗白色念珠菌的活性来源于α-松油醇、异松油烯、α-松油烯、松油烯-4-醇、桧烯、1,8-桉叶油素;豚鼠皮肤在连续5 d涂抹4%樟树精油后出现轻微的红斑,而4%松油烯-4-醇在涂抹2 d后就会出现轻微的红斑;另外,4%松油烯-4-醇会明显增加小鼠的血管通透性。研究结果为樟树精油的开发利用及治疗白色念珠菌相关疾病提供理论依据。     

Effects of natural antioxidants in the improvement of corn oil quality: olive leaf vs. lemon balm

Commercially available corn oil was enriched in polyphenols by adding olive leaf and lemon balm extracts, respectively. First, dried and ground plants were extracted through homogeniser‐assisted extraction. Then, the dried extracts were partially dissolved into the corn oil by means of solid–liquid extraction method. Total phenolic content increased 9.5 and 2.5 times over the pure corn oil. The antioxidant activities of enriched oil by olive leaf and lemon balm extracts have been found almost 14 and 6 times higher than that of untreated oil, respectively. Olive leaf extract enhanced the quality better than lemon balm extract with respect to carotenoid (TCC) and chlorophyll contents. Addition of 0.12–0.15% natural antioxidants gave rise to increase in the stability of the oil (≈18%).     

Bioactivity of Lemon Balm Kombucha

There is inadequate published data referring to bioactivity of lemon balm tea and its Kombucha. The aim of this study, therefore, was to investigate antimicrobial, antiproliferative, genotoxic, and antigenotoxic potential of lemon balm tea and its Kombucha with consuming acidity. Antimicrobial activity was determined by agar-well diffusion method. Cell growth effects were determined in HeLa, MCF7, and HT-29 human tumor cell lines. Genotoxic and antigenotoxic effects were determined using chromosome aberration assay in Chinese hamster cell line CHO-K1. Differences between control and treated groups were evaluated using analysis of variance, at significance level of p < 0.05. Kombucha from lemon balm tea (Melissa officinalis L.) exibited antimicrobial activity against prokaryotic microorganisms independently of their cell wall structure (both Gram-positive and Gram-negative bacteria), while there was no observed activity against eukaryots (yeasts and moulds). There was absence of genotoxic effects while antigenotoxic effects of lemon balm Kombucha and tea were confirmed on MMC-damaged CHO-K1 cells. For the explanation of cell growth effects that were not concentration dependent, concept of hormesis was used. Antiproliferative activity was lower compared with traditional Kombucha and Satureja montana L. Kombucha, with lemon balm tea showing higher activity than its Kombucha.     

改进型Clevenger装置提取柠檬果皮精油及成分分析

研究Clevenger装置改进前后对尤力克柠檬精油提取率和精油成分的影响;采用改进型Clevenger装置分别提取了青柠、尤力克、艾伦尤力克、费米耐劳、无籽里斯本5个不同柠檬品种的果皮精油,通过气相色谱-质谱法对其进行成分分析和结构鉴定,得到不同品种的柠檬果皮精油成分的指纹图谱。结果表明,Clevenger装置改进后尤力克柠檬精油的提取率增加了63.37%,且对精油挥发性成分种类无显著影响;5个柠檬品种中分别检测到51、50、41、43种和42种挥发性成分,主要为烯烃类、醇类、醛类、酯类以及少量的酸类和酮类。烯烃类物质是各个品种精油成分中最主要的组分,其中特征香气成分D-柠檬烯相对含量最高,β-蒎烯、γ-松油烯次之。品种间差异较大,除了含有32个共有成分之外,每个品种都存在自身特有的挥发性成分。     

Antioxidant activity of fresh and dry herbs of some Lamiaceae species

The herbs of lemon balm, oregano, and peppermint were analysed immediately after harvest and after drying to determine their antioxidant activity and content of total phenolics, l-ascorbic acid, and carotenoids. The strongest inhibition of linoleic acid (LA) peroxidation was found for fresh and dried oregano. For peppermint and lemon balm it was significantly lower and decreased after drying. The ability to scavenge the free radical DPPH (2,2-diphenyl-1-picrylhydrazyl) was very high in almost all tested samples, exceeding 90%. The three species tested had a very high content of total phenolics and drying of oregano and peppermint resulted in their considerable increase. The highest content of ascorbic acid was determined in fresh peppermint and lemon balm and carotenoid content was at a similar level in all the species tested. Drying caused great losses of these compounds.