The in vitro antioxidant and antimicrobial activities of the essential oil and various extracts of Origanum syriacum L var bevanii

The present work examines the in vitro antioxidant and antimicrobial properties of the essential oil and various extracts from the herbal parts of Origanum syriacum L var bevanii. Polar subfractions of methanol extracts from both deodorised and non‐deodorised materials showed the highest DPPH (2,2‐diphenyl‐l‐picrylhydrazyl) radical‐scavenging activity, with IC₅₀ values of 21.40 and 26.98 µg ml^?1 respectively, whereas the IC₅₀ of the essential oil was 134.00 µg ml^?1. The antioxidant potential of the extracts appeared to be closely related to the presence of polar phenolics. However, the inhibitive effect on linoleic acid oxidation might be promoted by the presence of non‐polar phenolics, as both hexane and dichloromethane extracts showed high antioxidant activities. The antimicrobial activity of the essential oil was superior to those of the other extracts. Nineteen compounds representing 962 g kg^?1 of the essential oil were identified; carvacrol (669 g kg^?1) was the main component. Overall, the results suggest that the essential oil and extracts from the herbal parts of O syriacum could be used as natural preservative ingredients in the food industry. Copyright © 2004 Society of Chemical Industry     

蒌叶挥发油的提取及抗氧化和抑菌活性研究

采用水蒸气提取法对蒌叶挥发油进行提取,在单因素实验的基础上,以正交实验筛选最佳的提取工艺条件;同时考察蒌叶挥发油抗氧化和抑菌活性。结果表明,蒌叶挥发油提取的最佳工艺条件为:料液比m_干蒌叶粉∶V_水=50∶1000（g/m L）,超声时间为30 min,超声温度70℃,超声功率192 W,加热回流提取4 h,蒌叶挥发油的得率为2.96%。蒌叶挥发油清除DPPH·和·OH的IC₅₀分别为33.19、71.11μg/m L;挥发油对金黄色葡萄球菌、枯草杆菌、大肠杆菌、蜡状芽孢杆菌、四联球菌、藤黄八叠球菌、白色葡萄球菌、黑曲霉、毛霉、青霉均有明显的抗菌活性,其MIC分别为0.625、1.25、0.625、0.625、0.625、2.50、1.25、0.313、0.625、0.313 mg/m L,故蒌叶挥发油具有较强的抗氧化和抑菌活性。      

草果精油的化学组成、抗氧化及抑菌活性研究

以正己烷为溶剂提取草果精油,利用气相-质谱联用技术（GC-MS）分析其化学成分,同时研究了草果精油的抗氧化和抑菌活性。结果表明,草果精油成分比较复杂,其中有23种化合物被鉴定,主要成分为香叶醇（29.42%）、橙花叔醇（9.87%）、十八碳烯酸（8.62%）等。草果精油对DPPH和ABTS自由基均显示出了较好的清除效果,EC50值分别为3.84、3.20mg/mL;不同浓度的草果精油对5种测试菌都有一定的抑菌作用,其中对大肠杆菌的抑菌效果最好,其最低抑菌浓度（MIC）为2.0mg/mL。      

Antibacterial and antifungal activities of selected microalgae and cyanobacteria

In vitro activity of nine cyanobacterial and ten microalgal newly isolated or culture collection strains against eight significant food‐borne pathogens has been evaluated and compared. Water extracts and culture liquids of Gloeocapsa sp. and Synechocystis sp. demonstrated the widest spectrum of activity with minimal inhibitory concentration (MIC) ranging from 1.56 to 12.5 mg mL^?1. Culture liquid of Anabaena sp. had the highest activity (MIC = 0.39 mg mL^?1) but only to Gram‐positive bacteria. Ethanol extracts and fatty acids from all cyanobacteria and microalgae were active against Streptococcus pyogenes and/or Staphylococcus aureus. The fatty acids of Synechocystis sp. inhibited the growth of Bacillus cereus, Escherichia coli and Candida albicans (MIC values of 2.5–1.25 mg mL^?1, respectively). Exopolysaccharides (EPS) of Gloeocapsa sp. were the sample that exhibited activity against all test pathogens with lowest MIC values (0.125–1 mg mL^?1). High activity with a narrower range of susceptible targets demonstrated the exopolysaccharides of Synechocystis sp. and Rhodella reticulata. Antimicrobial activity was proven for phycobiliproteins isolated from Synechocystis sp., Arthrospira fusiformis, Porphyridium aerugineum and Porphyridium cruentum, respectively. In conclusion Gloeocapsa sp. and Synechocystis sp. and especially their exopolysaccharides showed the most promising potential against the examined food pathogens.     

柠檬果皮精油的化学组成、抗氧化及抑菌活性研究

采用GC-MS法分析经水蒸气蒸馏法所提柠檬果皮精油的化学组分,并对其抗氧化与抑菌活性进行了研究。实验结果表明:鉴定出23种挥发性成分,占精油总量的94.57%,主要为dl-柠檬烯（42.93%）、γ-萜品烯（8.41%）、α-松油醇（6.39%）和E-柠檬醛（6.09%）等;柠檬精油对OH自由基有较好的清除效果,清除率可达95.14%;而对DPPH自由基的清除率在实验条件下最高为34.81%,远低于同浓度的PG和TBHQ。200mg/kg添加量的柠檬精油可延缓猪油和花生油的贮藏期,但略差于同浓度TBHQ和VE的抗氧化效果。抑菌活性实验结果表明柠檬精油对6种供试菌都有一定的抑菌作用,其中对大肠杆菌的抑菌效果最好,其最低抑菌浓度（MIC）为0.1μL/m L。      

肉桂精油抗氧化性能及清除自由基能力的研究

对肉桂精油(CEO)的抗氧化和清除游离基活性的比较是基于总体抗氧化能力、清除超氧阴离子自由基能力、清除羟基自由基能力、抗亚油酸脂质过氧化能力、清除DPPH自由基5个方面,并与其他的合成抗氧化剂如BHT、PG做比较。实验结果表明,在一定浓度范围内,CEO的羟自由基清除能力强于BHT和PG;清除超氧阴离子自由基的能力强于PG;清除DPPH自由基能力、抗氧化活性比BHT和PG弱;CEO抑制亚油酸的过氧化能力比BHT和PG略弱。实验表明了CEO在某些方面具有良好的抗氧化效果。     

薰衣草挥发油的抗氧化活性测定和成分比较

利用水中蒸馏和水上蒸馏提取薰衣草挥发油,采用试剂盒法对其抗氧化活性进行测定,应用GC-MS技术测定其化学成分,结果表明水中蒸馏所的薰衣草挥发油的抗氧化能力比水上蒸馏所的薰衣草挥发油的抗氧化能力强,共鉴定出20种化合物,其中主要的且相同的化合物有6种,分别占相对百分含量的63.03%和75.57%,芳樟醇的含量分别占相对百分含量的43.46%和27.06%,这可能是导致不同方法提取的薰衣草挥发油抗氧化能力不同的主要原因。     

芹菜籽精油的抑菌与抗氧化作用研究

目的:测定芹菜籽精油(Celery seed essential oil)对几种常见食品污染微生物的抑菌活性以及抗氧化作用。方法:采用琼脂扩散法及肉汤稀释法测定精油的抑菌作用、采用DPPH(对二苯代苦味肼基)法、ABTS(2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐)法、清除超氧离子法和抗亚油酸脂质过氧化法测定芹菜籽精油的清除自由基、抗氧化作用。结果:芹菜籽精油对于多种病原性微生物有良好的抑制作用,尤其对于革兰氏阳性菌,抑制效果尤为明显。并且,芹菜籽精油具有良好的清除自由基、抗氧化的作用,其作用要强于丁基羟基苯甲醚(BHA)和二丁基羟基甲苯(BHT)。     

Chemical composition and inhibitory effect of essential oil and organic extracts of Cestrum nocturnum L. on food-borne pathogens

In this study, we examined the chemical compositions of essential oil and tested the efficacy of oil and organic extracts of Cestrum nocturnum L. against food-borne pathogens. The chemical compositions of the oil was analysed by gas chromatography-mass spectrometry (GC-MS). Forty-seven compounds representing 93.28% of the total oil were identified. The oil [5 μL of 1:5 (v/v) dilution of oil with methanol] and organic extracts of hexane, chloroform, ethyl acetate and methanol (300 μg per disc) of C. nocturnum displayed a great potential of antibacterial activity against Staphylococcus aureus (ATCC 6538 and KCTC 1916), Listeria monocytogenes (ATCC 19166 and ATCC 15313), Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa KCTC 2004, Salmonella typhimurium KCTC 2515 and Escherichia coli ATCC 8739. Also the oil had strong detrimental effect on the viable count of the tested bacteria. The results obtained from this study may contribute to the development of new antimicrobial agents with potential applications in food industries as natural preservatives to control food-borne pathogens.     

Microalgal and cyanobacterial cell extracts for use as natural antibacterial additives against food pathogens

Intra‐ and extracellular extracts of thirteen cyanobacteria and twelve microalgae were screened for their activity against a few of the most relevant food‐borne pathogens – viz. Salmonella sp., Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. Strain M2‐1 of Scenedesmus obliquus was the microalga that exhibited the highest antibacterial activity, except against Salmonella sp. Although cyanobacteria possessed in general wider antibacterial spectra than microalgae, the former have also been associated with toxin production – and may thus be less useful in food formulation. Nostoc sp. was particularly effective against E. coli and P. aeruginosa, whereas Gloeothece sp. stood out because of its capacity to inhibit all food pathogens tested. Typically, the intracellular extracts were more powerful than their extracellular counterparts; and those with antibacterial features were found to possess high contents of long chain fatty acids – some of which are well‐known for their antibacterial activities.     

分段提取香茅草精油及其对食用油脂的抗氧化活性研究

目的:提取云南产香茅草精油,研究不同提馏段精油对食用油脂的抗氧化活性。方法:采用水蒸气蒸馏法分段提取香茅精油,并以猪油和菜籽油为介质,过氧化值（POV）为指标,考察香茅精油的抗氧化活性,以BHT和BHA做对照。结果:水蒸气蒸馏法提取香茅精油的最佳工艺为:料液比为1∶20,Na Cl的质量浓度为7g/L,提取时间为160min,总出油率为1.23%。GC-MS分析前20min和20¹60min香茅精油中柠檬醛、橙花醛、橙花醇等主要成分的含量差别较大。香茅精油对猪油的抗氧化活性较低。20¹60min香茅精油对菜籽油有较好的抗氧化活性,与VC复合使用时,其对菜籽油的抗氧化活性与BHT相当。20¹60min精油对DPPH·的清除能力较BHT和BHA差,而其总抗氧化活性与BHT和BHA相当。结论:香茅草精油具有较好的抗氧化活性,并且精油中高沸点物质的活性大于低沸点物质的活性。      

罗勒精油的微波辅助提取工艺及其抑菌效果研究

采用微波辅助提取罗勒精油,优化了实验条件对精油得率的影响。在单因素实验的基础上,通过正交实验对提取工艺进行优化。将所得精油作为抑菌剂,结合滤纸片法和二倍稀释法,确定了罗勒精油的抑菌活性和最低抑菌浓度(MIC)、最低杀菌浓度(MBC)。结果表明:选用粗粉碎干料罗勒,在料液比1∶16 g/m L,Na Cl浓度4%,浸泡时间6 h,微波功率567 W,微波时间120 s的条件下,罗勒精油的最佳得率为0.3758%(n=3)。罗勒精油对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌均有抑制作用,最低抑菌浓度分别为31.25、62.5、125μg/m L,最低杀菌浓度分别为31.25、125、500μg/m L,表明抑菌作用大小为:大肠杆菌(E.coli)>枯草芽孢杆菌(B.subtilis)>金黄色葡萄球菌(S.au Teus)。该研究为罗勒的综合利用与开发提供了理论依据。      

姜精油的超临界CO2提取及其抗氧化性研究

采用正交试验的方法,确定了超临界CO2萃取姜精油的最佳工艺条件萃取温度40℃,萃取压力20MPa,萃取时间90min;研究了姜精油在植物油和动物油中的抗氧化性能,结果表明,生姜的超临界CO2提取物是一种良好的天然抗氧化剂,柠檬酸、BHT、TBHQ对其增效显著.     

七叶鬼灯檠挥发油及不同提取物抑菌活性的研究

研究了七叶鬼灯檠根状茎的挥发油及不同提取物的体外抑菌活性,为七叶鬼灯檠资源开发利用提供科学依据。采用滤纸片法和牛津杯法对七叶鬼灯檠根状茎挥发油及其甲醇、丙酮和乙酸乙酯提取物体外抑菌能力进行评价。结果表明,七叶鬼灯檠根状茎挥发油表现出较强的抑菌活性,对肺炎克雷伯氏菌抑制作用最强,其次为巨大芽孢杆菌和粘红酵母,抑菌圈直径分别为(29.11±0.31)、(26.77±0.35)、(26.20±0.62)mm。在不同溶剂提取物中,丙酮提取物和甲醇提取物均有明显的抑菌效果,解脂假丝酵母对提取物最敏感。七叶鬼灯檠的挥发油及提取物含有天然抑菌活性物质,具有光谱的抑菌效果,值得进一步开发利用。      

Chemical composition,antioxidant and cytotoxicity activities of the essential oils of Myristica fragrans and Morinda citrifolia

BACKGROUND: In this study the chemical composition, antioxidant activities and cytotoxic effect of the essential oils of Myristica fragrans (nutmeg) and Morinda citrifolia (mengkudu) were determined. RESULTS: Thirty‐eight compounds in nutmeg oil and six compounds in mengkudu oil were identified by gas chromatography–mass spectrometry. The free radical scavenging activity of nutmeg oil was superior of that mengkudu oil. The MTT assay of nutmeg oil on human colorectal carcinoma (HCT‐116) and human breast carcinoma (MCF‐7) cell lines showed IC₅₀ values of 78.61 and 66.45 µg mL^?1, respectively. The mengkudu oil exhibited IC₅₀ values of 91.46 and 78.15 µg mL^?1 for HCT‐116 and MCF‐7, respectively. CONCLUSION: The results showed that nutmeg oil can be developed as potent anti‐cancer and antioxidant drugs. Copyright © 2011 Society of Chemical Industry     

Profile of antioxidant and antibacterial activities of different solvent extracts from Rabdosia rubescens

The objective of this work was to investigate the antioxidant and antibacterial activities of different extracts from Rabdosia rubescens and to further evaluate the antibacterial mechanism of extracts. The results showed that 80% acetone extracts had the highest contents of total polyphenols (8.09 mg GAE g^?1) and flavonoids (5.69 mg RE g^?1) and exhibited the strongest antioxidant activities, followed by 80% methanol and 80% ethanol, and the lowest for hexane extracts. Others except for hexane extracts showed different antibacterial activities against Gram‐positive strains, while no inhibitory effects were found on tested Gram‐negative bacterial strains. Among these extracts, 80% acetone and ethanol extracts had relatively higher antibacterial activities with the lowest minimum inhibitory concentration and minimum bactericidal concentration values of 5 and 10 mg mL^?1. The antibacterial mechanism of ethanol extracts against Staphylococcus aureus might be described as it disrupts cell wall, increases cell membrane permeability and then leads to the leakage of cell constituents.     

The influence of harvest time on essential oil composition,phenolic constituents and antioxidant properties of Turkish oregano (Origanum onites L.)

BACKGROUND: The aim of this research was to determine essential oil composition, phenolic constituents and antioxidant properties of Turkish oregano (Origanum onites L.) leaves harvested during the months of June to September. RESULT: The maximum essential oil yield in the leaves appeared in the middle of July. The main components of oregano oil were carvacrol, thymol, γ‐terpinene, p‐cymene, α‐terpinene and α‐pinene. Carvacrol was highest in the July harvest. The maximum extract yield was found in September. Oil distilled from early‐season (June) harvested leaves had the highest antioxidant ability, expressed as low concentration providing 50% inhibition of free radical scavenging activity and high levels of reducing/antioxidant capacity. Twelve phenolic compounds of oregano extract were identified and the main components were found to be rosmarinic acid and acecetin. The maximum rosmarinic acid and acecetin were found in harvests of July and June, respectively. Total phenolic contents, free radical scavenging activities and reducing/antioxidant capacities were found to be highest in the July harvest. DISCUSSION: All yields, chemical compositions, free radical scavenging activities and reducing/antioxidant capacities of extracts and essential oils of Turkish oregano changed importantly depending on vegetative periods of growing season. Copyright © 2009 Society of Chemical Industry