Chemical Characterization and Biological Potential of the Essential Oil of Eucalyptus globulus Labill

Oxidation of lipids in various products,along with the growth of medically important pathogens,has led to a search for medicinal plants with antioxidant and antimicrobial activities.As a result,the aim of this study was to evaluate the antioxidant and antibacterial activity of the essential oil of Eucalyptus globulus(EO-Eg).Antioxidant activity was assessed by using the 2,2-diphenyl-1-picrylhydrazyl hydrate(DPPH)assay method.Existing components were identified through gas chromatography-mass spectrometry(GC-MS)analysis.Antibacterial activity and minimum inhibitory concentration(MIC)were assessed by using the broth microdilution method with standard multidrug-resistant bacterial strains.The main EO-Eg compounds identified by GC-MS were isopulegol,citronellal,and citronellol,which are primarily used in the industrial sectors.EO-Eg demonstrated excellent antioxidant activity with an effective concentration(EC50)of 4.48μL/mL owing to the presence of phenolic compounds.Regarding antibacterial activity,the EO-Eg displayed a broad antimicrobial spectrum of antimicrobial activity across the different resistance phenotypes analyzed.The most notable antibacterial activity was observed against Staphylococcus aureus 169 MRSA(MIC=0.0625%).As a result,our findings suggest that EO-Eg has antioxidant and antibacterial potential against hospital-acquired multidrug-resistant pathogens,which may be correlated with its major components.

Antibacterial activity of the essential oils from the leaves of Eucalyptus globulus against Escherichia coli and Staphylococcus aureus

Objective:To examine the in vitro antimicrobial activities of essential oil of the leaves of Eucalyptus globulus(E.globulus).Methods:The essential oils of this plant were obtained by the hydrodistillation method.The inhibitory effects of this essential oil were tested against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)by using agar disc diffusion and dilution broth methods.Results:The results obtained showed that essential oil of the leaves of E.globulus has antimicrobial activity against gram negative bacteria(E.coli)as well as gram positive bacteria(S.aureus).Conclusion:The encouraging results indicate the essential oil of E.globulus leaves might be exploited as natural antibiotic for the treatment of several infectious diseases caused by these two germs,and could be useful in understanding the relations between traditional cures and current medicines.

Transcript Level Analysis of Lignin and Flavonoid Biosynthesis Related Genes in <i>Eucalyptus globulus</i>

We have investigated a correlation of transcript abundances of key genes that influence the quality of wood and flavonoid biosynthesis, such as the two p-hydroxycinnamoyl-CoA:quinate shikimate p-hydroxycinnamoyl transferase (HCT) and the two chalcone synthases (CHS) from Eucalyptus globulus grown in a greenhouse. The EglHCT1 and EglHCT2 transcripts accumulated in stems of all ages, but to a lesser extent in leaves. On the other hand, EglCHS3 and EglCHS4 exhibited high transcript levels in leaves, roots and shoots, but low levels in the stem. A positive correlation (R2 > 0.70) was observed between the transcript levels of the EglHCT1, EglHCT2 genes and Klason lignin (KL) content. In addition, the sum of transcript levels of EglHCT1 and EglHCT2 genes were highly correlated to KL contents (R2 > 0.85). However, there is no relationship between transcript levels of two CHS genes and, KL or flavonoid contents. This may imply that lignin biosynthesis and flavonoid biosynthesis are independently regulated in E. globulus.

Antibacterial Activity of <i>Bougainvillea Glabra, Eucalyptus Globulus, Gnaphalium Attenuatum</i>, and Propolis Collected in Mexico

Bougainvillea glabra C., Eucalyptus globules Labill., and Gnaphalium attenuatum DC., as well as propolis, have been used in Mexican traditional medicine as a remedy to treat respiratory illnesses. There are few biological reports of such material collected in Mexico, despite the high demand for them as raw material for popular and industrial uses. The antibacterial activity of the plants and propolis studied here were evaluated against a panel of bacteria using three different methodologies: agar disc diffusion, macro and micro dilution methods. E. globules and G. attenuatum extracts showed the strongest active values (P > 0.05) in the agar disc diffusion method with a range of 8 - 22 mm inhibition zone, MIC values ranging from 25 - 250g/mL, and MBC values of 25 - 500g/mL obtained by macro and micro dilution methods. B. glabra extracts were active against E. coli, S. typhi, K. pneumoniae, S. aureus and S. agalactiae, with 8 - 13 mm inhibition zone, MICs ranging from 500 - 3000g/mL, and MBCs of 1000 - 3000g/mL. The propolis extract turned out to be active against E. coli, K. pneumoniae, S. aureus and S. agalactiae, with values of 7 - 12 mm, MICs of 1000 - 2000g/mL, and MBCs of 2000 - 2500g/mL. E. globules and G. attenuatum extracts were the most active in the three methodologies assayed. This is also the first time that the antibacterial activity of G. attenuatum has been experimentally demonstrated. The microdilution method showed to be more sensitive, less expensive and minor time-consuming technique compared with the other two.

Eucaglobulin, A New Complex of Gallotannin and Monoterpene from Eucalyptus globulus

Eucaglobulin 1, a new complex of gallotannin and monoterpene, was isolated from the leaves of Eucalyptus globulus. Its structure was determined by spectral methods.

Response of soil respiration to a severe drought in Chinese Eucalyptus plantations

Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in soil respiration in a plantation of Eucalyptus globulus. We documented a clear seasonal pattern in soil respiration with the highest values (100.9 mg C-CO2 m(-2) h(-1)) recorded in June and the lowest values (28.7 mg C-CO2 m(-2) h(-1)) in January. The variation in soil respiration was closely associated with the dynamics of soil water driven by the drought. Soil respiration was nearly twice as great in the wet seasons as in the dry seasons. Soil water content accounted for 83-91% of variation in soil respiration, while a combined soil water and soil temperature model explained 90-99% of the variation in soil respiration. Soil water had pronounced effects on soil respiration at the moisture threshold of 6-10%. Soil water was strongly related to changes in soil parameters (i.e., bulk density, pH, soil organic carbon, and available nitrogen). These strongly influenced seasonal variation in soil respiration. We found that soil respiration was strongly suppressed by severe drought. Drought resulted in a shortage of soil water which reduced formation of soil organic carbon, impacted soil acid-base properties and soil texture, and affected soil nutrient availability.

Note on Glycaspis brimblecombei Moore (Hemiptera Psyllidae): A new pest of Eucalyptus in Greece

Leaves of eucalyptus infested by Glycaspis brim-blecombei Moore were found on river red gum (E. camaldulensis) and blue gum (E. globulus) trees in Attiki and Chania region, Greece. The psyllid is recorded for the first time in Greece. Brief information about this psyllid is provided.

Factors determining the occupancy of nest-boxes by Great Tits(Parus major)in eucalypt plantations

Providing nest-boxes as surrogate tree cavities can be of great importance to increase the breeding populations of cavity-nesting birds in managed forests.However,the exact placement of nest-boxes should be taken into consideration to enhance their occupancy according to species-specific preferences.In this study,we investigated which factors can better predict nest-box occupancy by the Great Tit(Parus major)in eucalypt plantations.We used generalised linear mixed-effects models to analyse the influence of topography,nest-box positioning,vegetation cover and landscape variables on three-year occupancy records from 80 newly provided nest-boxes.Non-random patterns of nest-box occupancy were found with respect to all categories except topography.Results suggest that Great Tits prefer to occupy high-placed nest-boxes,close to areas that can provide them with supplementary resources either within or in the vicinity of the stand(i.e.,trees other than eucalypts,riparian vegetation,and large patches of adjacent habitats).Overall,this study provides important recommendations for nest-box placement and spatial distribution in managed forests and enhances the potential of nest-box interventions as a biodiversity offset and management tool.

蓝桉果实中的脂溶性成分(英文)

从蓝桉（Eucalyptus globulus Labill．）果实乙醇提取物的石油醚部位分离鉴定出6个化合物，通过理化和波谱分析结构鉴定为：5-羟基-4′，7-二甲氧基-6-甲基黄酮（1）、blumenol A（2）、蓝桉醇（3）、绿花白干层醇（4）、β-谷甾醇（5）、二十二烷酸（6），其中化合物1～4和化合物6系首次从该植物中分离得到，化合物1和2首次从桉属植物中分离得到。

GC-MS对蓝桉果实及大叶桉果实挥发油成分研究

目的:用气相色谱-质谱法对蓝桉果实和大叶桉果实挥发性成分进行研究。方法:采用水蒸气蒸馏法从2种中药中提取挥发油,然后经毛细管色谱柱进行分离,用归一化法计算含量。色谱条件:DB-WAX石英毛细管柱(30 m×0.32mm,0.25μm),柱温条件:起始温度40℃(3 min)5℃·min-1 250℃(10 min),MS检测器,进样量1μL,载气He(1.0 mL·min-1)。质谱分析条件:电离方式为EI,离子源温度200℃,电子能量70 eV。结果:蓝桉果实挥发油中鉴定出31个成分,大叶桉果实中鉴定出34个成分,两者指纹谱存在较大差异。结论:本法可靠,可用于2种果实化学成分的鉴别。

分光光度法测定蓝桉果实总三萜酸

目的:建立香草醛 冰醋酸体系分光光度法测定蓝桉果实中总三萜酸的方法。方法:利用在高氯酸的条件下香草醛 冰醋酸 与三萜酸的反应测定总三萜酸。结果:总三萜酸在17.64～105.84μg范围呈良好线性关系,测定样品回收率为95.22%。结论:该法 简便、快速、灵敏。

蓝桉果实中的五环三萜化学成分(英文)

从蓝桉果实乙醇提取物的乙酸乙酯部位分离得到7个五环三萜化合物,经理化和波谱分析鉴定为3β-乙酰基-乌索-11,12-烯-28,13β内酯(1)、桦木酮酸(2)、白桦脂酸(3)、2α-羟基白桦脂酸(4)、2α,3β-二羟基乌苏-12-烯-28-酸(5)、熊果酸(6)、3β-羟基-乌索-11,12-烯-28,13β内酯(7),其中化合物1,4,5和7系首次从该植物中分离得到。

蓝桉枝、叶气态挥发物对种子萌发的自毒作用

为了解蓝桉枝、叶气态挥发物的自毒作用,在透明密闭保鲜盒内用蓝桉不同质量新鲜枝、叶气态挥发物对蓝桉种子进行处理,探讨了蓝桉枝、叶高浓度(0.077 2g/cm3)、中等浓度(0.025 7g/cm3)和低浓度(0.008 5g/cm3)气态挥发物对种子萌发的自毒作用.结果表明:鲜叶、鲜枝气态挥发物对蓝桉种子萌发(发芽率、发芽势、发芽速率)的效应趋势基本相同,表现为高浓度抑制种子萌发,随浓度降低,抑制作用减弱,甚至转变为促进作用的规律;但鲜叶、鲜枝气态挥发物处理对种子萌发影响的程度不同,中高浓度时,鲜叶气态挥发物处理种子的化感抑制作用明显强于鲜枝处理;经t检验表明,除中等浓度处理种子发芽率未达显著水平外,鲜叶与鲜枝处理间差异都达极显著水平或显著水平;低浓度时,鲜叶与鲜枝气态挥发物处理抑制作用基本相同或鲜叶处理有较强的促进作用,鲜叶与鲜枝气态挥发物处理间差异都未达显著水平.

蓝桉果实抗稻瘟菌成分的分离及其活性(英文)

通过抗菌活性测定,蓝桉(Eucalyptus globulus Labill.)果实乙醇提取物中抗稻瘟菌活性成分主要存在于石油醚萃取部分和乙酸乙酯萃取部分。从石油醚部分和乙酸乙酯部分分离到的15个化合物中,β-桉叶油醇和β-谷甾醇对稻瘟菌孢子萌发具有较强的抑制活性,它们对稻瘟菌孢子萌发的半抑制浓度(IC50)分别为62.9和141.4μg/mL。其它化合物对稻瘟菌孢子萌发只有轻微的抑制活性。

蓝桉叶挥发油化学成分分析研究

采用乙醚为溶剂提取云南产蓝桉干叶的挥发油,经气相-质谱联用仪分析,得到57种组分,确定了其中54个化合物的结构,主要成分是1,8-桉叶素(68.61%),α-蒎烯(10.24%),别香橙烯(5.27%),乙酸松油酯(4.05%),香橙烯(1.45%),(-)-蓝桉醇(1.26%),α-松油醇(1.02%)等。采用峰面积归一法计算各组分的相对含量,所鉴定成分占总馏出峰面积的99.69%。

蓝桉叶挥发油化学成分的气相色谱-质谱分析研究

目的研究云南产蓝桉叶挥发油的化学成分。方法采用水蒸气蒸馏法提取云南产蓝桉叶挥发油,经气相-质谱联用仪分析其成分,采用峰面积归一化法计算各组分的相对含量。结果确定了云南产蓝桉叶挥发油中47个化合物,所鉴定成分占总馏出峰面积的99.17%,其主要成分是1,8-桉叶素(72.71%),α-蒎烯(9.22%),α-松油醇醋酸酯(3.11%),(-)-蓝桉醇(2.77%),α-松油醇(2.54%),别香橙烯(2.47%)。结论确定了云南产蓝桉叶挥发油的化学成分,为综合利用云南产蓝桉叶挥发油奠定了基础。

中草药“一口钟”的原植物鉴定及其精油的化学成分

云南,四川等省市售的中草药“一口钟”为蓝桉(Eucalyptus globulus Labill.)的果实.用气相色谱-质谱-计算机联用技术、标准品迭加和毛细管保留指数定性法,对其精油的化学成分进行分析.从分离的65个成分中,鉴定出36个成分,其含量占总组成的93.80％,主要成分是别香树烯(23.37％),1.8-桉叶油素(20.81％)、金合欢醇(9.95％)、α-水芹烯(8.30％)、δ-愈创木烯(5.95％)、δ-蒎烯(4.09％)、β-水芹烯(3.43％)、α-愈创木烯(3.15％)等.

GC法建立蓝桉挥发油指纹图谱研究

目的:建立云南产蓝桉挥发油的GC指纹图谱。方法:利用毛细管气相色谱,选择适宜的程序升温条件对蓝桉挥发油进行分析。结果:获得了蓝桉挥发油GC16个共有指纹图谱峰。结论:有了稳定的GC指纹图谱有助于对蓝桉挥发油的化学成分作进一步分析。

蓝桉对紫茎泽兰的化感作用及其生物测定

测定了蓝桉叶水提液(2%、5%、10%)、抽提后的蓝桉叶(2g、5g、10g)和阴干蓝桉叶(2g、5g、10g)对紫茎泽兰种子萌发和幼苗生长的影响。结果表明:蓝桉叶水提液能降低紫茎泽兰种子发芽率、发芽速度、胚根和胚轴长度及幼苗生长,浓度越高效果越明显(2%水提液对发芽率的作用除外),但低浓度有时会促进紫茎泽兰种子的萌发和幼苗新生叶片数;以蓝桉作为竞争植物与紫茎兰竞争以抑制其生长,且蓝桉不会对当地其他植物造成伤害。

蓝桉枝、叶气态挥发物对幼苗生长的自毒作用

为了解蓝桉枝、叶气态挥发物的自毒作用,用蓝桉不同浓度新鲜枝、叶对蓝桉种子进行处理。结果表明:鲜叶、鲜枝气态挥发物对蓝桉幼苗生长(胚轴长、胚根长、鲜重、干重)影响的规律基本相同,呈现出高浓度抑制,随浓度降低,抑制作用减弱,甚至转变为促进作用的规律。但鲜叶、鲜枝处理对幼苗生长影响的程度大小不同,高浓度时,鲜叶处理对各测试指标的化感抑制作用明显强于鲜枝处理,多重比较表明鲜叶与鲜枝处理间差异都达极显著水平,随浓度降低,鲜叶与鲜枝处理间差异减少,中等浓度时,鲜叶处理后胚轴长、胚根长与鲜枝处理间差异都达显著水平,低浓度时,鲜叶处理后胚轴长、胚根长与鲜枝处理间差异都达极显著水平。