Chemistry and biological significance of essential oils of Cymbopogon citratus from Pakistan

Steam distilled oil of Cymbopogon citratus was analyzed by Gas Chromatographic-Mass Spectrometry (GC-MS) and citral was found as major constituent. The oil exhibited significant inhibition of beta-glucuronidase activity and also showed activities against some tested human, plant and animal pathogens. The minimum inhibitory concentrations could not be determined due to the lack of some chemicals.     

Use of dimethyldioxirane in the epoxidation of the main constituents of the essential oils obtained from Tagetes lucida, Cymbopogon citratus, Lippia alba and Eucalyptus citriodora

Dimethyldioxirane (DMDO), a widely used oxidant in organic synthesis is considered an environmentally friendly oxygen transfer reagent because acetone is the only byproduct formed in its oxidation reactions. This work describes the isolation of the main constituents (terpenes) in the essential oils obtained from Tagetes lucida, Cymbopogon citratus, Lippia alba and Eucalyptus citriodora, their epoxidation with DMDO in acetone solution and the characterization of the resulting epoxides by GC-MS (EI) and NMR. This is one of the first reports involving the application of dioxirane chemistry to essential oils in order to generate modified compounds with potential uses in several areas of medicine and industry.     

Feasibility of near-infrared spectroscopy and chemometrics analysis for discrimination of Cymbopogon nardus from Cymbopogon citratus

The authenticity of essential oils has become an important issue in supplying essential oil raw materials for the pharmaceutical, perfume, and cosmetic industries. Citronella oil is one of the essential oils used in those industries. Cymbopogon nardus is one of the lemongrass species that can produce citronella oil. However, with the high price of citronella oil from C. nardus, there is a possibility of being substituted or adulterated with closely related plants, namely Cymbopogon citratus. This paper described the feasibility of near-infrared (NIR) spectroscopy combined with chemometrics analysis for rapid identification and authentication of C. nardus from C. citratus essential oil. NIR spectra of both essential oils and their mixture (10 % and 25 % v/v of C. citratus in C. nardus) showed a similar spectral profile, so we cannot easily discriminate them and need help from chemometrics analysis. For chemometrics analysis, we used absorbance data from the preprocessed NIR spectra at wavenumbers 4000–6500 cm^?1. Using PCA, we could separate each essential oil from C. nardus and C. citratus but cannot discriminate between 10 % and 25 % of CC in CN. While using OPLS-DA with R2X(cum) = 0.88, R2Y(cum) = 0.859 and Q2(cum) = 0.723, we could group each sample. The OPLS-DA score plot clearly shows the difference between C. nardus and C. citratus essential oils and their mixtures. The combination of NIR and OPLS-DA could provide a suitable method for identifying and authenticating C. nardus from C. citratus essential oil.     

A study of the substances present in essential oils

Conclusions The essential oil ofJuniperus pseudosabina Fisch. et Mey, obtained from small flowers by steam distillation has been investigated. It has been established that it contains not less than 43 components, of wich the following have been identified:l--pinene (67%), camphene (0.5%),l--pinene (3.5%), sabinene (0.5%), ³-carene (0.3%), -myrcene (1.2%), -phellandrene (0.1%),l-limonene (0.7%),l--phellandrene (0.2%), -terpinene (0.3%), p-cymene (0.2%), terpinolene (0.1%), methyl n-nonyl ketone (2.4%), d-thujone (0.3%),l-camphor (0.2%), d-terpinen-4-ol (0.3%),l-linalool (0.7%),l-borneol (0.3%),l-terpineol (0.4%), nerol (0.2%), geraniol (0.25%), d-cedrol (12%), elemol (0.3%), eudesmol (0.35%), and sesquiterpene hydrocarbons (5.6%):l--cedrene,l--elemene,l--cedrene, d--cadinene, d-ar-curcumene,l-calamenene, and d-calacorene.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 482–487, 1969     

Chemical composition of essential oils of plants of the genus Schizonepeta

Tomsk State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 290–291, March–April, 1989.     

Multidimensional liquid chromatography for the determination of chiral coumarins and furocoumarins in Citrus essential oils

In this work the enantiomeric distribution of chiral coumarins (meranzin and epoxyaurapten), and furocoumarins (oxypeucedanin, byakangelicol, and epoxybergamottin) in different Citrus essential oils (lemon, lime, grapefruit, and bitter orange) was determined by means of a heart-cutting multidimensional-liquid chromatography (MD-LC) system, equipped with a microsilica column in the first dimension in a combination to a cellulosic-based chiral column used in the second dimension. The normal phase-liquid chromatography-liquid chromatography (NP-LC-LC) instrumentation was equipped with a photodiode array detector and a multiport valve as interface. For method optimization and the determination of absolute configuration, natural compounds were isolated and racemic mixture was synthesized. The NP-LC-LC/PDA (where PDA is photodiode array) method provided a good baseline separation of chiral coumarins (meranzin and epoxyaurapten) and furocoumarins (epoxybergamottin and byakangelicol) present in cold-pressed Citrus essential oils without any sample pretreatment. Results obtained showed that for all the chiral compounds present in Citrus essential oils analyzed, there is always a clear prevalence of one of the two enantiomers, and do not appear influenced by the different geographical origin of the oils.     

Comparative analysis of the oil and supercritical CO(2) extract of Cymbopogon citratus Stapf

Dried and ground leaves of lemon grass (Cymbopogon citratus Stapf.) were used as a matrix for supercritical extraction of essential oil with CO(2). The objective of this study was to analyze the influence of pressure on the supercritical extraction. A series of experiments were carried out, for 360 min, at 50 degrees C and at different pressures: 90, 100, 110 and 120 bar. Extraction conditions were chosen to maximize citral content in the extract oil. The collected extracts were analysed by GC-MS and their composition was compared with that of the essential oil isolated by hydrodistillation and by steam distillation. At higher solvent density the extract aspect changes passing from a characteristic yellow essential oil to yellowish semi-solid mass because of the extraction of high molecular mass compounds. The optimum conditions for citral extraction were 90 bar and 50 degrees C, at these conditions citral represent more than 68% of the essential oil and the extraction yield was 0.65% while the yield obtained from hydrodistillation was 0.43% with a content of citral of 73%.     

Activity antifungal of the essential oils; aqueous and ethanol extracts from Citrus aurantium L.

Our study is about the essential oil of Citrus aurantium L. in Tunisia and its plant extract. The yield of this essential oil is 0, 56% but the yield of the extract of plant was 17.1% for the aqueous extract ant 18.3% for the ethanolic extract. The analysis of chemical composition by using GC and GC/MS showed the essential oil of C. aurantium L. species to be rich in monoterpenes such as α-terpineol, lianolyl acetate, linalool and limonene. The antifungal activity of this oil showed us an inhibition of the germination of mushrooms, in the same way we could note that the biologic activities are generally assigned to the chemotypes high content in oxygenated monoterpene.     

Formulation Effects in the Antioxidant Activity of Extract from the Leaves of Cymbopogon citratus (DC) Stapf

Cymbopogon citratus DC (Stapf.) is a perennial grass and it is distributed around the world. It is used as a condiment for food and beverage flavouring in the form of infusions and decoctions of its dried leaves. Our previous studies have shown antioxidant, anti-inflammatory and gastroprotective activities for the infusion and its phenolic fractions. The aim of the present work was to develop oral dosage forms from a Cymbopogon citratus extract to be used as a functional food with antioxidant properties. Initially, an essential oil-free infusion was prepared, lyophilized and characterized by HPLC-PDA. Total phenols were quantified with the Folin–Ciocalteu method and the antioxidant activity was assessed by DPPH assay. Gelatine capsules containing the extract with different excipients, selected after DSC and IR trials, were prepared. A formulation exhibiting better antioxidant behaviour in a gastric environment was attained. These results suggest that the proposed formulation for this extract could be a valuable antioxidant product and, consequently, make an important contribution to “preventing” and minimizing diseases related to oxidative stress conditions.     

K-Means聚类分析法筛选柠檬香茅茎叶差异蛋白及鉴定

柠檬香茅含有大量的香茅精油,运用十分广泛,然而其茎、叶的精油含量却相差悬殊。 为探索柠檬香茅精油代谢相关的蛋白途径,本文对柠檬香茅旗叶、成熟叶及茎秆等材料进行精油含量、总蛋白含量测定及双向凝胶电泳(2-DE)表达谱分析,运用k-means聚类分析方法对2-DE电泳中差异蛋白斑点的丰度、等电点和相对分子质量进行聚类分析和讨论,结果表明,旗叶和茎秆上调表达的蛋白质斑点的聚类对于相对分子质量变化敏感,成熟叶上调表达蛋白质斑点对于丰度的变化较为敏感。 预测了精油代谢功能相关的蛋白质斑点15个,挖取预测蛋白质斑点通过基质辅助激光解吸电离飞行时间质谱(MALDI-TOF/TOF-MS)成功鉴定了9个蛋白质。 本研究为柠檬香茅精油的蛋白代谢途径提供新的基础信息及研究思路。     

Characterization of some essential oils and their key components: Thermoanalytical techniques

The present study was aimed at determining the kinetics of evaporation and establishing vapor pressure curves for both single and multi-component systems by thermogravimetry (TG) and differential scanning calorimetry (DSC). Essential oils (e.g. lavender oil, orange oil, clove oil and eucalyptus oil, etc.) are typically multi-component systems consisting of various volatile pure components (e.g. linalyl acetate, limonene, cinnamaldehyde, etc.) which resemble single component systems. In this study linalyl acetate was taken as the calibration compound for TG. The vapor pressure curves for the pure substances were plotted using TG and vapor pressure plots for clove oil and eucalyptus oil were constructed using DSC. The thermodynamic and kinetic parameters of the pure compounds were compared to that of the multi-component systems to quantitatively and qualitatively measure the influence of different compounds on each other. The k-value from the vapor pressure data for linalyl acetate was calculated as 112006 Pa kg^0.5mol^0.5s^-1 m^-2 K^-0.5. The vapor pressure values were used to determine the Antoine constants using the SPSS 10.0 software.This revised version was published online in November 2005 with corrections to the Cover Date.     

Component composition of essential oils from four species of the genus Achillea growing in Kazakhstan

The component composition of the four species Achillea filipendulina, A. sudetica, A. ledebourii, and A. cartilaginea was studied by GC-MS. It was found that the principal components of the essential oil (%) were santolina alcohol (29.1) and borneol (27.9) for A. filipendulina, linalool (11.8) and caryophyllene (8.9) for A. sudetica, germacrene D (20.55) for A. ledebourii, and α-thujone (26.15) and β-thujone (11.76) for A. cartilaginea. The chemical composition of the essential oils from A. sudetica, A. ledebourii, and A. cartilaginea was studied for the first time. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 243–245, May–June, 2006.     

桂花精油化学成分研究

用水蒸汽蒸馏法对江苏产桂花精油进行了提取, 并用GC-MS联用仪对其有效成分进行了测定. 结果表明: 江苏产桂花精油的香味成分主要是萜烯、醇类、氧化芳樟醇类、 5-己基二氢呋喃-2-酮、紫罗兰酮类、邻苯二甲酸酯类, 其中邻苯二甲酸酯类含量最大. 对水蒸汽蒸馏后的桂花水溶液进行萃取和GC-MS测试, 进一步证实了邻苯二甲酸酯的存在. 与其它产地的桂花精油化学成分比较, 其主要的香味成分基本相同, 但邻苯二甲酸酯含量不同, 这一研究结果表明: 研究不同产地的香料香味成分时需要将多种提取方法结合;对现有应用于化妆品和食用香精的桂花精油是否含有邻苯二甲酸酯需作进一步的研究.