萃取方法对花椒精油的化学成份、生物活性研究

采用气相色谱-质谱联用(gas chromatography-mass spectrography,GC-MS)技术研究不同萃取方法获得的花椒精油的风味成分。结果显示,3种萃取方法获得的精油主要成份基本相同,只是含量略有差异。主要有1-(2-羟基-4,6-甲氧基苯基)-乙基酮(水蒸汽蒸馏39.83%、超临界萃取41.06%、亚临界萃取35.46%)、3-甲基-6-(1-甲基乙基)-2-环己烯-1-酮(水蒸汽蒸馏5.22%、超临界萃取3.95%、亚临界萃取4.36%)、4-亚甲基-1-(1-甲基乙基)-环己烯(水蒸汽蒸馏4.19%、超临界萃取3.65%、亚临界萃取3.84%)、β-水芹烯(水蒸汽蒸馏3.15%、超临界萃取2.68%、亚临界萃取3.02%)等。抗菌试验表明,花椒精油对金黄色葡萄球菌、伤寒沙门氏菌、绿脓杆菌的抗菌活性非常好,而且3种提取方法提取的精油的抗菌活性差异不大。花椒精油对黑曲霉、假丝酵母具有较弱的抑菌作用。抗肿瘤试验结果表明,精油对MFC-7细胞具有最强的抑制率,对Hela细胞具有最弱的抑制率。总的来看,上述3种菌株的生长抑制率受上述3种方法提取的精油的影响效果差异不大。     

同时蒸馏萃取/GC-MS分析干黄酱的挥发性成分

通过同时蒸馏萃取的方法提取干黄酱的挥发性成分,经过气质联机分析,共分析出73种物质,鉴定出3-甲基丁醛(13·36%)、亚油酸乙酯(10·49%)、2-甲基丁醛(7·00%)、(反,反)-9,12-十八碳二烯酸(6·97%)、油酸乙酯(5·97%)、十六酸(5·05%)、苯乙醛(4·28%)、糠醛(3·51%)、1-(1H-吡咯基-2-)-乙酮(3·01%)、糠醇(1·96%)、3-甲基-1-丁醇(1·32%)、5-羟甲基糠醛(0·97%)、3-甲硫基丙醛(0·84%)、2-甲氧基-4-乙烯基苯酚(0·82%)、2,5-二甲基-4-羟基-3(2H)-呋喃酮(0·27%)、3,4-二甲氧基苯酚(0·26%)等33种物质,总相对百分含量为76·84%。经过调配实验,确认了对干黄酱特征香气起主要作用的香料。     

当归茎叶精油对四种果蔬采后腐败真菌的抑制活性

为实现当归废弃物的资源化利用，探讨当归茎叶精油的化学组分及抑真菌活性，采用二倍稀释法确定了当归茎叶精油对4种常见采后病原真菌[互隔交链孢(Alternaria alternata)、硫色镰刀菌(Fusarium sulphureum)、粉红单端孢(Trichothecium roseum)和扩展青霉(Penicillium expansum)]最低抑菌浓度(minimum inhibitory concentration, MIC)和最低杀菌浓度(minimum fungicidal concentration, MFC),并用滤纸片熏蒸法和雾化熏蒸法分别研究了当归茎叶精油对4种真菌菌丝生长的体外抑制作用和体内条件下对T.roseum的抑制效果。结果表明，当归茎叶精油的提取得率为0.057%。在当归茎叶精油中共鉴定出了51种化合物，2, 4, 5-三甲基苯甲醛(22.7%)含量最高，其次是α-蒎烯(11.1%)、十氢-3-甲基-7-亚甲基-1-(1-甲基乙基)(6.69%)、α-法呢烯(6.44%)、反式-蛇床内酯(5.84%)和β-蒎烯(5.16%)。当归茎叶精油对F.sulphur...     

GC-MS分析自制豆豉中挥发性风味化合物的研究

采用水蒸气蒸馏法提取自制豆豉的挥发性风味化合物,并采用气相色谱-质谱法(GC-MS)鉴定其组成成分.通过GC-MS分析共鉴定出41个挥发性化合物,包括醇(6),酚(7),醛(2),酮(3),酸(8),含N,S化合物(13),烃(2)等7类.结果显示豆豉中主要挥发性风味化合物有:吲哚、四甲基吡嗪、油酸、三甲基吡嗪、二十一烷、棕桐酸、笨甲醛、亚油酸、4-乙烯基-2-甲氧基笨酚、笨甲酸、愈创木酚、苯酚、硬脂酸、2-呋喃甲醇,12-甲基十四烷酸、十五酸、4-甲基-2,6-二叔丁基笨酚,3-乙基-2,5-二甲基吡嗪、笨甲醇、4-乙烯基苯酚、苯乙醇,2,5-二甲基吡嗪,4-甲基-2,6-二叔丁基-4-羟基-环己二烯-1-酮、肉豆蔻酸等24种,占挥发性化合物总量的92.9%.其中对豆豉的风味起重要作用的吡嗪类含量最高.     

气相色谱质谱法测定木醋液饮料中化学成分

采用气相色谱-质谱联用(GC-MS)技术对木醋液饮料化学成分进行分离鉴定,用色谱峰面积归一化法确定各组分的相对含量。从木醋液饮料中分离出了51个组分,鉴定出了40个化合物,占总面积的96.07%。并测定了各化合物的相对含量,包括2,6-二甲氧基苯酚(30.12%)、乙酸(15.63%)、γ-丁内酯(4.78%)、1,2,4-三甲氧基苯(4.19%)、苯酚(4.84%)、愈创木酚(2.85%)、3-甲基-1,2-环戊二酮(4.79%)、3-甲基-2-环戊烯-1-酮(3.72%)等。通过对木醋液饮料化学成分的研究,为木醋液资源的进一步开发利用提供参考。     

不同贮藏时间普洱生茶的特征性香气成分分析

贮藏时间是影响普洱生茶品质最重要的因素之一,而香气成分又是构成普洱生茶品质重要的物质基础;因此以同厂家、同批号、不同贮藏时间的普洱生茶(7542)为原料,采用顶空-固相微萃取和气相色谱-质谱联用分析其香气成分,同时结合主成分、相关性和聚类分析筛选出普洱生茶在贮藏过程中的特征性香气成分。结果表明:(1)普洱生茶样中共检测到74种香气成分;(2)随着贮藏时间的延长,醇和酸类呈下降趋势,碳氢化合物、酚类、甲氧基苯类和其他呈增加趋势,酮和醛类无明显变化规律,酯类保持稳定;(3)经主成分和相关性分析,将16种香气(反-芳樟醇氧化物、乙基芳樟醇、4-萜品醇、α-松油醇、二氢猕猴桃内酯、柠檬烯、4-异丙基甲苯、4-乙基苯酚、3,5-二甲基苯酚、2-甲氧基-4-甲基苯酚、3,4-二甲氧基甲苯、1,2,3-三甲氧基苯、1,2,3-三甲氧基-5-甲基苯、4-乙基-2-甲氧基苯酚、4-乙基-1,2-二甲氧基苯和1,2,4-三甲氧基苯)筛选为不同贮藏时间普洱生茶的特征性香气成分;(4)上述特征性香气成分可将不同贮藏时间的普洱生茶很好地分类聚类。     

同时蒸馏萃取/气相色谱-质谱法分析火麻仁精油成分

采用同时蒸馏萃取法(SDE)提取火麻仁精油,精油得率为0.096%,然后经气相色谱- 质谱联用技术对火麻仁精油成分进行分离鉴定。分离出128 种成分,鉴定出95 种挥发性成分,占火麻仁精油总成分的90.88%。其中主要成分为α- 石竹烯(7.59%)、十五烷酸(5.74%)、4- 羟基-2- 苯乙酮(5.45%)、a,a,4- 三甲基苯甲醇(5.38%)、萘及其衍生化合物(5.22%)、呋喃酮(3.49%)、1- 甲氧基-4-(1- 丙烯)- 苯(3.71%)、石竹烯氧化物(3.59%)、D- 柠檬烯(3.16%)、苯乙醛(3.03%)、3- 甲氧基丙二醇(2.97%)、苯酚类(2.85%)、葎草烯(2.56%)、环己烯醇(2.14%)、吲哚(1.64%)、1,3,3- 三甲基环庚烷醇(1.41%)、己醛(1.18%)、8- 甲基-1- 十一碳烯(1.15%)、十四烷烃(1.07%)、柠檬醛(1.02%)。     

气相色谱-质谱分析熏制罗非鱼片的风味成分

采用固相微萃取技术有效提取液熏罗非鱼片和传统烟熏罗非鱼片中的呈味物质,并通过气相色谱-质谱法对提取的风味成分进行分析。结果表明：熏制罗非鱼片中的酚类、酯类、酸类等化合物协同作用构成其独有的烟熏风味,其中主要风味成分为苯酚、2-甲氧基苯酚、2-甲基苯酚、4-甲基苯酚、3-甲基苯酚、2-甲氧基-4-甲基苯酚、2,4-二甲基苯酚、2,6-二甲氧基苯酚、2,6-二叔丁基对甲酚、乙酸丙酯、乙酸、丙酸乙酯、乙酸丁酯等。液熏罗非鱼片与传统烟熏罗非鱼片中检出的风味成分分别有33种和30种,其中有26种相同,所占比例分别为91.53%和92.27%,其中液熏罗非鱼片检测到10个酚类化合物和4个酯类化合物,总相对含量达到55.63%;传统烟熏罗非鱼片检测到12个酚类化合物和4个酯类化合物,总相对含量达到57.09%。通过比较液熏罗非鱼片与传统烟熏罗非鱼片的风味成分的种类和含量表明,液熏罗非鱼片在风味成分上与传统烟熏罗非鱼片相近。     

旋覆花挥发油成分的GC-MS分析

采用水蒸气蒸馏法提取旋覆花全草挥发油,出油率为0.32%。采用GC-MS联用技术对挥发油成分进行分离鉴定,面积归一化法确定各成分的相对含量,从其中鉴定出34个化学成分,鉴定成分占总峰面积的99.85%。旋覆花挥发油的主要化学成分分别为植酮(21.75%)、长叶烯(9.71%)、棕榈酸(7.98%)、邻苯二甲酸二丁酯(7.40%)、肉豆蔻酸(7.38%)、2,6-二甲基-4-甲氧基甲基苯酚(7.04%)、2-(对-茴香基)-4-甲基己烯(5.26%)、石竹素(5.03%)、邻苯二甲酸二异丁酯(4.75%)等。鉴定出的34种成分中脂肪类占45.5%,芳香类成分占26.74%,萜类占26.43%,其他类占1.18%。     

广陈皮精油的特异性分析

本研究采用水蒸气蒸馏法,提取广陈皮和来自广西、浙江、四川地区陈皮的精油,同等质量广陈皮的精油含量高于其他地区陈皮(p<0.05)。采用气相色谱-质谱(GC-MS)从精油中共鉴定出111种组分,其中48种组分是第一次在广陈皮中被分析鉴定到。利用主成分分析(PCA)和热图(heatmap)对广陈皮与其他地区陈皮精油组分及含量进行统计学分析,发现存在明显差异:不仅表现在相对含量较高的D-柠檬烯、γ-松油烯、2-(甲氨基)苯甲酸甲酯,还表现在一些相对含量较少的α-合金欢烯、松油醇和石竹烯等成分上。偏最小乘法判别分析(PLS-DA)陈化一年和两年的广陈皮精油组分和含量,首次揭示对广陈皮与其他地区陈皮的差异来源贡献较大的化合物还有香芹酮(0.03%~0.23%)、(E,E,E)-2,6,10-三甲基-2,6,9,11-十二烷四烯-1-醛(0.03%~0.80%)、紫苏醛(0.04%~0.34%)、4-甲基-1-甲基乙基-双环-己2烯(0.51%~0.84%)和6,6-二甲基-2-亚甲基-双环庚烷(1.42%~2.28%);其中香芹酮、(E,E,E)-2,6,10-三甲基-2,6,9,11-十二烷四烯-1-醛和紫苏醛仅在广陈皮中检测到,而4-甲基-1-甲基乙基-双环-己2烯和6,6-二甲基-2-亚甲基-双环庚烷在广陈皮中的含量显著高于其它地区陈皮。另外,陈化一到五年的优质广陈皮精油PLS-DA分析结果显示,陈化一年的广陈皮与陈化两到五年的广陈皮精油差异较大,提示陈化的最初两年是广陈皮陈化特定风味物质形成的关键点,是研究陈化机理的重要时期。     

Chemical Composition and Antimicrobial Activity of the Essential Oil from the Peel of Shatian Pummelo (Citrus Grandis Osbeck)

The chemical composition of the essential oil obtained from the peel of Shatian pummelo was analyzed by gas chromatography/mass spectrometry. Twenty-one components were identified. The monoterpenes and sesquiterpene hydrocarbons were the principal compound groups with 96.64% (w/w) of the total oil, among which, limonene was observed dominant (89.96 ± 1.64%), followed by β-myrcene (4.49 ± 0.38%), α-pinene (0.63 ± 0.05%), 3-carene (0.48 ± 0.04%), caryophyllene (0.47 ± 0.04%), and other minor constitutes. Esters, alcohols, ketones, aldehydes, and ether represented 3.15% of the total oil. Results by the disc diffusion method and minimum inhibitory concentration determination method showed that the essential oil contained a wide-spectrum antimicrobial activity against Penicillium chrysogenum ATCC 10106, Bacillus subtilis ATCC 21616, Staphylococcus aureus ATCC 25923, and Escherichia coli ATCC 25922, with their inhibition zones ranging from 8.27 ± 1.07 mm to 20.71 ± 1.50 mm. The MIC values were ranging from 4.69 to 37.50 μL/mL. However, no inhibition effect was observed on the Aspergillus niger ATCC 16888.     

Daphne oleoides: An alternative source of important sesquiterpenes

This study was targeted to characterize the chemical composition and antibacterial properties of Daphne oleoides subsp. oleoides essential oil. The essential oil was analyzed and quantified by gas chromatography and gas chromatography/mass spectrometry. Additionally, the broth dilution method was used to evaluate its antibacterial activity against Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Streptococcus faecalis (ATTC 29212), Escherichia coli (ATCC 25922), Proteus mirabilis (ATCC 25933), Proteus vulgaris (ATCC 13315), Pseudomonas aeruginosa (ATCC 27853), and Salmonella typhi Ty2 (ATCC 19430). Seventy-nine compounds were identified, representing 95.2% of the total oil. Nootkatone (18.5%), nootkatin (12.1%), and daphnauranol C (11.7%) were determined as the main constituents in the oil. Oxygenated sesquiterpenes were dominating in the oil (43.0%), followed by fatty acid derivatives (13.7%) and carbonylic compounds (9.6%). The minimal inhibitory/bactericidal concentrations of essential oils of D. oleoides were in the range from 25–100 μg/mL, which can be considered as high activity in comparison with the reference antibiotic which was active in the rangefrom 3.12–100 μg/mL. The greatest minimal inhibitory concentration value was determined as 25 µg/mL against both two Bacillus strains and S. epidermidis, B. cereus, B. subtilis, and S. aureus were the most sensitive strains against essential oils when compared with the minimal inhibitory concentrations of control antibiotic. Consequently, Daphne oleoides subsp. oleoides can be exploited as a source of natural antibacterial agents and nootkatone for the pharmaceutical, food, and agricultural industries.     

斜叶黄檀精油功能活性

本文主要测定斜叶黄檀精油中的挥发性成分、多酚和黄酮含量,采用体外抗氧化评价斜叶黄檀精油的清除DPPH和ABTS自由基能力、总还原力和总抗氧化能力,以金黄色葡萄球菌(G+)、化脓性链球菌(G+)、大肠杆菌(G-)、铜绿假单胞菌(G-)、鼠伤寒沙门氏菌(G-)以及白色念珠菌(真菌)为待测菌,评价精油的抑菌效果,通过对酪氨酸酶的抑制活性评价精油抑制黑色素的形成能力。结果表明斜叶黄檀精油在浓度为0.18 mg/mL时,对DPPH和ABTS自由基的清除能力均达到70%左右,在浓度分别为0.18 mg/mL和1 mg/mL时,总还原力和总抗氧化能力的吸光度值均达到0.4以上。对金黄色葡萄球菌、化脓性链球菌以及白色念珠菌的抑菌圈直径分别为:12.83、11.50和10.25 mm,呈现中敏程度的抑制性,但对三种革兰氏阴性菌无明显的抑制效果。精油对酪氨酸酶的抑制活性要强于阳性对照熊果苷,在浓度为0.1 mg/mL抑制率将近90%。本文得出斜叶黄檀精油有较好的抗氧化活性、抑制革兰氏阳性菌和真菌以及抑制酪氨酸酶活性,比较完善的介绍了斜叶黄檀精油的功能活性。     

野生糙苏籽挥发油化学成分的分析

用水蒸汽蒸馏法从野生糙苏籽中提取挥发油,利用气相色谱- 质谱联用技术对其挥发油中的化学成分进行分离和结构鉴定,运用气相色谱面积归一化法确定各个成分的相对百分含量。从糙苏籽的挥发油中鉴出56 种成分,其主要成分为α- 里哪醇(13.38%)、石竹烯氧化物(11.21%)、1- 辛烯-3- 醇(8.38%)、邻苯二甲酸二异丁酯(8.22%)、亚麻酸乙酯(6.21%)等。对糙苏籽的挥发油进行了抗氧化实验和抗菌实验,结果表明糙苏籽挥发油对·OH 有明显的清除作用,糙苏籽的挥发油对实验菌株均有明显的抑制和灭活作用,特别是大肠杆菌ATCC25922 株和肺炎球菌32201 株的抑制作用表现得更为显著。     

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.     

Chemical composition and inhibitory parameters of essential oil and extracts of Nandina domestica Thunb. to control food-borne pathogenic and spoilage bacteria

The aim of this study was to examine the chemical composition of the essential oil isolated from the floral parts of Nandina domestica Thunb. by hydrodistillation, and to test the efficacy of essential oil and various organic extracts against a panel of food-borne pathogenic and spoilage bacteria such as Bacillus subtilis ATCC6633, Listeria monocytogenes ATCC19166, Staphylococcus aureus KCTC1916, S. aureus ATCC6538, Pseudomonas aeruginosa KCTC2004, Salmonella typhimurium KCTC2515, Salmonella enteridis KCCM12021, Escherichia coli 0157-Human, E. coli ATCC8739, E. coli 057:H7 ATCC43888 and Enterobacter aerognes KCTC2190. The chemical composition of essential oil was analysed by GC-MS. It was determined that 79 compounds, which represented 87.06% of total oil, were present in the oil. The oil contained mainly 1-indolizino carbazole (19.65%), 2-pentanone (16.4%), mono phenol (12.1%), aziridine (9.01%), methylcarbinol (4.6%), ethanone (3.3%), furfural (2.96%), 3,5-dimethylpyrazole (1.29%) and 2(5H)-furanone (1.32%). The oil (1000 ppm/disc), and various organic extracts of hexane, chloroform, ethyl acetate and methanol (1500 ppm/disc) exhibited promising antibacterial effect as a diameter of zones of inhibition (9-18 and 7-13 mm) and MIC values (62.5 to 1000 and 250 to 2000 microg/ml), respectively against the tested bacteria. Also the oil had strong detrimental effect on the viable count of the tested bacteria. These results indicate the potential efficacy of plant-based natural products such as essential oil and organic extracts of N. domestica to control food-borne pathogenic and spoilage bacteria.     

Chemical composition and insecticidal activities of the essential oil of Perilla frutescens (L.) Britt. aerial parts against two stored product insects

The chemical composition of the essential oil of Perilla frutescens (L.) Britt. aerial parts and its insecticidal activity against Tribolium castaneum and Lasioderma serricorne were investigated. The essential oil of P. frutescens was obtained by hydrodistillation and a total of 34 components in the essential oil were identified with GC–MS. It was found that the main compounds included 2-furyl methyl ketone (71.83 %), decahydro-1-methyl-2-methylene-naphthalene (10.47 %), limonene (5.16 %) and caryophyllene (1.66 %). With a further isolation, the two active constituents were obtained from the essential oil and identified as 2-furyl methyl ketone, limonene. In the progress of assay, it showed that the essential oil and 2-furyl methyl ketone exhibited stronger contact and fumigant activities against the two stored product insects than limonene. Moreover, the essential oil and its constituents exhibited the comparable repellency against the two stored product insects, relative to the positive control, DEET. The results indicate that the essential oil of P. frutescens aerial parts and its isolated compounds have potential for development into natural insecticides or fumigants as well as repellents for control of insects in stored grains.     

Antimicrobial and Antioxidant Potentials of Essential Oil and Acetone Extract of Myristica fragrans Houtt. (Aril Part)

ABSTRACT: The antifungal, antibacterial, and antioxidant potentials of essential oil and acetone extract were carried out by different techniques. In poison food medium method, the essential oil showed complete zones of inhibition against Fusarium graminearum at the all tested doses. For other tested fungi and bacteria, they gave good to moderate zone inhibition. The antioxidant activity was evaluated by measuring peroxide, thiobarbituric acid and total carbonyl values of rapeseed oil at fixed time intervals. Both the extract and essential oil showed strong antioxidant activity in comparison with butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). In addition, their inhibitory action in linoleic acid system was studied by monitoring peroxide concentration in emulsion during incubation. The results were well correlated with above values. Their radical scavenging capacity was carried out on 2,2'-diphenyl-1-picrylhydracyl (DPPH) radicalm, and they showed strong scavenging activity in comparison with synthetic antioxidants. Their reducing power was also determined, which also proved strong antioxidant capacity of essential oil and extract. Gas chromatographic-mass spectroscopy studies on essential oil resulted in the identification of 49 components representing 96.49% of the total amount, and the major component was sabinene (20.22%), followed by terpinen-4-ol (12.08%), safrole (10.32%), αpinene (9.7%), β-phellandrene (6.56%), and γ-terpinene (5.93%). The acetone extract showed the presence of 23 components representing 71.66% of the total amount. The major components were isocroweacin (18.92%), elemicin (17.68%), methoxyeugenol (8.13%), linoleic acid (4.12%), dehydrodiisoeugenol (4.06%), palmitic acid (2.8%), and trans-isoeugenol (2.76%).     

In vitro control of food-borne and food spoilage bacteria by essential oil and ethanol extracts of Lonicera japonica Thunb.

The antibacterial potential of essential oil from flowers and ethanolic leaf extracts of Lonicera japonica Thunb. was evaluated for controlling the growth of a range of food-borne pathogens. Thirty-nine compounds representing 92.34% of the total oil were identified, of which trans-nerolidol (16.31%), caryophyllene oxide (11.15%), linalool (8.61%), p-cymene (7.43%), hexadecanoic acid (6.39%), eugenol (6.13%), geraniol (5.01%), trans-linalool oxide (3.75%), globulol (2.34%), pentadecanoic acid (2.25%), veridiflorol (1.83%), benzyl alcohol (1.63%) and phenylethyl alcohol (1.25%) were the major compounds. The oil and extracts revealed a remarkable antibacterial effect against Listeria monocytogenes ATCC 19116, Bacillus subtilis ATCC 6633, B. cereus SCK 11, Staphylococcus aureus (ATCC 6538 and KCTC 1916), Salmonella enteritidis KCTC 12021, S. typhimurium KCTC 2515, Enterobacter aerogenes KCTC 2190 and Escherichia coli ATCC 8739. However, no effect was observed for Pseudomonas aeruginosa KCTC 2004 and E. coli O157:H7 ATCC 43888. Our findings demonstrate that the oil and extracts derived from L. japonica might be a potential source of preservatives for use in the food or pharmaceutical industries.     

Inhibitory parameters of the essential oil and various extracts of Metasequoia glyptostroboides Miki ex Hu to reduce food spoilage and food-borne pathogens

The aim of this work was to examine the chemical composition of the essential oil and various solvent extracts isolated from the floral cone of Metasequoia glyptostroboides Miki ex Hu and to test their efficacy against a diverse range of organisms comprising food spoilage and food-borne pathogenic bacteria. The chemical composition of essential oil isolated by hydrodistillation was analysed by GC-MS. It was determined that 59 compounds, which represented 97.06% of total oil, were present in the oil. The oil contains mainly α-pinene (29.54%), totarol (9.37%), α-thujene (8.63%), bornylene (8.63%), β-caryophyllene (4.40%), totarol acetate (3.98%), δ-3-carene (3.19%) and 2-β-pinene (2.25%). The oil was found containing mainly the oxygenated mono- and sesquiterpenes and their respective hydrocarbons. Antibacterial activity of essential oil, methanol extract and various organic sub-fractions of methanol extract of M. glyptostroboides was determined in vitro using agar diffusion method and MIC determination test against eleven (four Gram-positive, seven Gram-negative) bacterial strains including food spoilage and food-borne pathogens. The essential oil (5 μl/ml, corresponding to 1000 ppm/disc), methanol extract and various organic sub-fractions (7.5 μl/ml, corresponding to 1500 ppm/disc) of M. glyptostroboides exhibited great potential of antibacterial activity against four Gram-positive bacteria such as Bacillus subtilis (ATCC 6633), Listeria monocytogenes (ATCC 19166), Staphylococcus aureus (KCTC 1916), S. aureus (ATCC 6538) and one Gram-negative bacterium, Pseudomonas aeruginosa (KCTC 2004). The zones of inhibition of different concentrations of essential oil, methanol extract and its derived various organic sub-fractions against the tested bacteria were found in the range of 10 ∼ 20 mm and the MIC values were recorded between 125 and 1000 μg/ml. This study shows that M. glyptostroboides mediated essential oil and extracts can be applied in food industries as a natural preservatives or flavoring additives to control food spoilage and food-borne pathogenic bacteria causing severe destruction in food.