Contribution of microwave accelerated distillation in the extraction of the essential oil of Zygophyllum album L.

Introduction – The aerial parts of Zygophyllum album L. are used in folk medicine as an antidiabetic agent and as a drug active against several pathologies. In this work we present the chemical composition of Algerian essential oils obtained by microwave accelerated distillation (MAD) extraction, a solventless method assisted by microwave. Objective – Under the same analytical conditions and using GC‐FID and GC‐MS, the chemical composition of the essential oil of Zygophyllum album L. extracted by MAD was compared with that achieved using hydrodistillation (HD). Methodology – The extracted compounds were hydrosoluble, and they were removed from the aqueous solution by a liquid extraction with an organic solvent. Results – Employing MAD (100°C, 30 min), the essential oil contained mainly oxygenated monoterpenes with major constituents: carvone and α‐terpineol. However, most of the compounds present in the hydrodistilled volatile fraction were not terpene species, with β‐damascenone as a major constituent. Conclusion – The MAD method appears to be more efficient than HD: after 30 min extraction time, the obtained yields (i.e. 0.002%) were comparable to those provided by HD after 3 h extraction. MAD seems to be more convenient since the volatile fraction is richer in oxygenated monoterpenes, species that are recognised for their olfactory value and their contribution to the fragrance of the essential oil. Copyright © 2010 John Wiley & Sons, Ltd.     

Unravelling the Scent of Vetiver: Identification of Character‐Impact Compounds

Vetiver oil is a highly esteemed basic ingredient of modern perfumery, but the nature of the constituents that really impart its typical and most sought woody‐earthy scent has remained controversial. Indeed, vetiver oil is considered as one of the most complex essential oils, being mostly composed of several hundreds of sesquiterpene derivatives with a large structural diversity. Its complexity has hindered the direct identification of its odoriferous components. We thus aimed at using a combination of GC×GC/MS and GC‐Olfactometry in order to identify most of its odor‐impact constituents. The olfactory analysis of vetiver oil and vetiveryl acetate revealed a huge variety of odors in both products. While khusimone has almost unanimously been recognized as the most characteristic vetiver odorant, we have identified several even more important contributors to the typical vetiver character.     

Chemodiversity of Volatile Oils in Thapsia garganica L. (Apiaceae)

The chemical composition of the volatile oils obtained from the roots, leaves, flowers, and stems of Thapsia garganica of Tunisian origin was investigated by GC‐FID and GC/MS analyses. Sesquiterpene hydrocarbons and oxygenated monoterpenes were predominant in the oils of all plant parts. Bicyclogermacrene (21.59–35.09%) was the main component in the former compound class, whereas geranial (3.31–14.84%) and linalool (0.81–10.9%) were the most prominent ones in the latter compound class. Principal‐component (PCA) and hierarchical‐cluster (HCA) analyses revealed some common constituents, but also significant variability amongst the oils of the different plant parts. This organ‐specific oil composition was discussed in relation to their biological and ecological functions. For the evaluation of the intraspecific chemical variability in T. garganica, the composition of the flower volatile oils from four wild populations was investigated. Bicyclogermacrene, linalool, and geranial were predominant in the oils of three populations, whereas epicubenol, β‐sesquiphellandrene, and cadina‐1,4‐diene were the most prominent components of the oil of one population. PCA and HCA allowed the separation of the flower oils into three distinct groups, however, no relationship was found between the volatile‐oil composition and the geographical distribution and pedoclimatic conditions of the studied populations.     

Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes,Plant Organs and Senegalese Sample Locations

The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 – 55.8%) and non‐terpenic oxygenated compounds (34.5 – 63.1%). The main components were (E)‐β‐ocimene (12.1 – 39%), octyl acetate (11.6 – 21.8%) and decanol (9.7 – 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.     

元宝草挥发油化学成分的研究

目的：首次研究元宝草叶及果实挥发油的成分,并比较它们的化学成分。方法：元宝草的叶和果实中的挥发油分别经同时蒸馏萃取的挥发油提取器提取（水蒸气蒸馏、乙酸乙酯萃取）,通过气相色谱－质谱分析,结合计算机检索技术对其化学成分进行分离和鉴定,应用色谱峰面积归一化法测定各成分的相对百分含量。结果：从元宝草叶及果实中分别鉴定了30和44种成分,各占挥发油的总量的85．13％和63．26％。叶与果实挥发油的化学成分相差很大。     

Comparative Chemical Composition of the Essential Oils Obtained by Microwave‐Assisted Hydrodistillation and Hydrodistillation from Agrimonia pilosa Ledeb. Collected in Three Different Regions of China

Conventional hydrodistillation (HD) and microwave‐assisted hydrodistillation (MAHD) were performed to obtain the volatile oils of Agrimonia pilosa Ledeb . harvested in three different regions of China, which were subsequently characterized by GC‐FID and GC/MS analyses. Compared with HD, MAHD was advantageous in terms of energy savings and extraction time (60 vs. 240 min for MAHD and HD, resp.). The chemical composition varied among the different oils obtained, and the variations in the contents of the main constituents of the oils were irregular. Hence, these variations affected both the quantity and composition of the oils. The oil yields (0.15–0.21%) were affected by the method of extraction and the region of harvest, with the maximum amount of oil obtained by MAHD for the plants collected in Hubei (HB) and the minimum yield obtained by HD for the plants from Zhejing (ZJ). Hexadecanoic acid constituted the major compound of the essential oils, with the highest content found in the oil obtained by HD for plants from HB (41.18%) and the lowest one found in the oil obtained by MAHD from plants from ZJ (11.83%). Microwave irradiation did not adversely affect the composition of the essential oils. The findings show that MAHD is a modern, green, and fast technology.     

鱼腥草挥发油的化学成分

The volatile oils from Houttuynia cordata Thunb. were obtained with supereritical CO2, steam distillation and petroleum ether extraction and analyzed qualitatively and quantitatively by GC-MS. The results showed that the chemical constituents of the volatile oils by three different methods are very different. The extraction rates of volatile oil by above-mentioned three extraction methods are 1.764%, 0.040% and 0.082%, respectively. The volatile oil extracted by supercritical CO2 extraction, which the content of houttuyninum reached 14.393 %, is better than those with traditional methods.     

Essential‐Oil Composition of Helichrysum italicum (Roth) G.Don ssp. italicum from Elba Island (Tuscany,Italy)

The composition of 21 essential‐oil samples isolated from Helichrysum italicum collected in seven locations of Elba Island (Tuscany, Italy), characterized by different soil types, during three different periods (January, May, and October 2010) was determined by GC‐FID and GC/EI‐MS analyses. In total, 115 components were identified, representing 96.8–99.8% of the oil composition. The oils were characterized by a high content of oxygenated monoterpenes (38.6–62.7%), while monoterpene and sesquiterpene hydrocarbons accounted for 2.3–41.9 and 5.1–20.1% of the identified constituents, respectively. The main oxygenated derivatives were nerol (2.8–12.8%) and its ester derivative neryl acetate (5.6–45.9%). To compare the chemical variability of the species within Elba Island and between the island and other localities within the Mediterranean area, studied previously, multivariate statistical analysis was performed. The results obtained showed a difference in the composition of the essential oils of H. italicum from Elba Island, mainly due to the environment where the plant grows, and, in particular, to the soil type. These hypotheses were further confirmed by the comparison of these oils with essential oils obtained from H. italicum collected on other islands of the Tuscan archipelago.     

Superheated water extraction of essential oils from Cinnamomum zeylanicum (L.)

Introduction – Superheated water extraction (SHWE) potentially provides an environmentally friendly and clean extraction technique which uses a minimum or no organic solvent. The scope and limitations of the technique have still to be fully explored. Objective – To investigate the application of SHWE to cinnamon (Cinnamomum zeylanicum L.) bark and leaves as typical plant materials to determine if this extraction method can yield a higher quality oil. Methodology – Samples of cinnamon bark or leaves were extracted at 200°C with water under pressure. The essential oils were obtained from the aqueous solution using a solid phase extraction cartridge and were then examined by GC‐MS. Results – Using superheated water extraction, cinnamon bark oil with over 80% cinnamaldehyde and cinnamon leaf oil containing up to 98% eugenol were obtained. Alternative solvent extraction methods were also studied but led to emulsion formation apparently because of the presence of cellulose breakdown products. Conclusion – Superheated water extraction offers a cheap, environmentally friendly technique with a shorter extraction time than hydrodistillation and yielded a higher quality oil with a higher proportion of eugenol than hydrodistillation. Copyright © 2010 John Wiley & Sons, Ltd.     

石香薷挥发油提取的比较研究

利用GC-MS对石香薷挥发油进行了定性、定量分析。采取超临界CO2萃取、水蒸气蒸馏和有机溶剂石油醚萃取这三种方法提取石香薷挥发油。这三种方法提取石香薷挥发油的主要成分基本相似,主要为含氧化合物(香薷酮、百里香酚和香荆芥酚)等,采取超临界CO2萃取和水蒸气蒸馏的石香薷挥发油品质较优。超临界CO2萃取法为提取石香薷挥发油的理想方法。     

Chemical Composition Variability of Essential Oils of Daucus gracilis Steinh. from Algeria

The chemical compositions of 20 Algerian Daucus gracilis essential oils were investigated using GC‐FID, GC/MS, and NMR analyses. Altogether, 47 compounds were identified, accounting for 90 – 99% of the total oil compositions. The main components were linalool ( 18 ; 12.5 – 22.6%), 2‐methylbutyl 2‐methylbutyrate ( 20 ; 9.2 – 20.2%), 2‐methylbutyl isobutyrate ( 10 ; 4.2 – 12.2%), ammimajane ( 47 ; 2.6 – 37.1%), (E)‐β‐ocimene ( 15 ; 0.2 – 12.8%) and 3‐methylbutyl isovalerate ( 19 ; 3.3 – 9.6%). The chemical composition of the essential oils obtained from separate organs was also studied. GC and GC/MS analysis of D. gracilis leaves and flowers allowed identifying 47 compounds, amounting to 92.3% and 94.1% of total oil composition, respectively. GC and GC/MS analysis of D. gracilis leaf and flower oils allowed identifying linalool (22.7%), 2‐methylbutyl 2‐methylbutyrate (18.9%), 2‐methylbutyl isovalerate (13.6%), ammimajane (10.4%), 3‐methylbutyl isovalerate (10.3%), (E)‐β‐ocimene (8.4%) and isopentyl 2‐methylbutyrate (8.1%) as main components. The chemical variability of the Algerian oil samples was studied using statistical analysis, which allowed the discrimination of three main Groups. A direct correlation between the altitudes, nature of soils and the chemical compositions of the D. gracilis essential oils was evidenced.     

A ‘Low‐Level’ Chemotaxonomic Analysis of the Plant Family Apiaceae: The Case of Scandix balansae Reut. ex Boiss. (Tribe Scandiceae)

Analyses by GC and GC/MS of an essential‐oil sample obtained from dry fruits of Scandix balansae Reut. ex Boiss . allowed the identification of 81 components, comprising 91.4% of the total oil composition. Interestingly, the major identified volatile compounds were medium‐chain‐length n‐alkanes, i.e., tridecane (6.7%), pentadecane (13.4%), and heptadecane (19.3%), and a long‐chain homolog nonacosane (7.6%). A number of minor oil constituents, among them tetradecyl 3‐methylbutanoate, and octadecyl 2‐methylpropanoate, 3‐methylbutanoate, and pentanoate, turned out to have a restricted natural occurrence not only in umbellifers but also in the Plant Kingdom, whereas the last ester is a new natural compound in general. The identity of these rare plant constituents that present excellent chemotaxonomic marker candidates for Scandix species was unambiguously confirmed by co‐injection of the oil sample with appropriate standards, which were synthesized for this purpose and fully characterized (¹H‐ and ¹³C‐NMR, IR, MS). To explore the possible applicability of the essential oils' compositional data in the taxonomy of Apiaceae, the herein studied and additional 58 oils obtained from Scandiceae taxa were compared using multivariate statistical analyses (MVA). MVA demonstrated that the evolution of the volatiles' metabolism of Scandiceae taxa was neither genera‐specific nor follows their morphological evolution.     

萼翅藤枝叶挥发油及其抗菌活性的研究

萼翅藤枝叶挥发油由GC/MS检测.树叶挥发油的52种成分中,氧化石竹烯(13.79%)、棕榈酸(11.91%)和β-石竹烯(10.45%)是主要成分.同时,树枝挥发油中的10种成分占总量的99.99%,其中主要的化学成分为棕榈酸(59.18%),亚油酸(12.70%)和邻苯二甲酸丁辛酯(8.21%).用滤纸扩散法,分别测定了枝、叶挥发油对8种微生物的抑制效果.枝、叶挥发油均具有很强的抗菌效果,并且抗细菌活性优于抗真菌活性.叶挥发油比枝挥发油具有更广谱的抑菌效果,且对所试的大多数菌株都具有更高的活性.     

槲寄生挥发性成分研究

目的：研究槲寄生挥发性成分。方法：利用水蒸汽蒸馏法提取槲寄生挥发性成分,用GC/MS进行分离测定,结合计算机检索技术对分离的化合物进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量。结果：分离出119个成分,确定了66个化合物,占挥发油总量的77．31％。结论：槲寄生挥发性成分大于2％的化学成分有12种。     

Volatile compounds with characteristic odour in moso‐bamboo stems (Phyllostachys pubescens Mazel ex Houz. De ehaie)

Introduction – Moso‐bamboo (Phyllostachys pubescens) is well known as an edible shoot in Asia, and the stems of moso‐bamboo are used as tableware due to its characteristic odour. Despite the pleasant odour of bamboo stems, no detailed analysis of the volatile compounds has been reported. Objective – To clarify the potent odourants contributing to the characteristic aroma of the bamboo, the aroma extract dilution analysis (AEDA) method was performed through gas chromatography olfactometry (GC‐O) analysis. In addition, relative flavour activity (RFA) was calculated, in which both the flavor dilution (FD) factor and weight percentage of each compound are involved. Results – Eighty‐nine compound in bamboo stems oil were identified by GC and GC‐MS. The main components of the oil were palmitic acid (16.5%), (E)‐nerolidol (10.2%) and indole (8.1%). In sensory analysis, 18 aroma‐active compounds were detected by aroma extract dilution analysis (AEDA). The most intense aroma‐active compounds were eugenol (sweet, clove‐like, green) and (E)‐2‐nonenal (green). Conclusion – The results of the sniffing test, RFA and FD factor indicated that (E)‐2‐nonenal and eugenol were estimated to have a bamboo‐like aroma, and aldehyde compounds, such as a phenylacetaldehyde (floral) and C9–C10 unsaturated aldehydes, make the aroma of bamboo. Copyright © 2010 John Wiley & Sons, Ltd.     

巴戟天挥发性成分研究

目的：研究巴戟天中的挥发性成分。方法：利用水蒸气蒸馏法提取巴戟天（Radix morindae offtcinalis）挥发油,用GC—MS进行测定,结合计算机检索技术对分离的化合物进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量。结果：鉴定出34个化学成分,其中相对百分含量大于2％的分别确定为L-龙脑（Bomeol L）29．28％,α-姜烯（Alpha—Zingiberene）4．88％,2-甲基-6-对甲基苯基-2-庚烯（Ar-Cureumene）4．49％,1-己醇（1-Hexanol）3．40％,β-倍半水芹烯（beta—sesquiphellandrene）3．34％,2-戊基呋喃（2-Amylfuran）3．32％,正壬醛（n—nonanal）2．17％,樟脑（L—camphor）2．07％,β-没药烯（bete—Bisabolene）2．06％。结论：34个挥发性成分均为首次从该植物中得到。     

Enantioselective GC–MS analysis of volatile components from rosemary (Rosmarinus officinalis L.) essential oils and hydrosols

Essential oils and hydrosols were extracted from rosemary harvested in different seasons, and the chemical compositions of volatile components in the two fractions were analyzed by gas chromatography–mass spectrometry (GC–MS). Enantiomers of some volatile components were also analyzed by enantioselective GC–MS. Classification of aroma components based on chemical groups revealed that essential oils contained high levels of monoterpene hydrocarbons but hydrosols did not. Furthermore, the enantiomeric ratios within some volatile components were different from each other; for example, only the (S)-form was observed for limonene and the (R)-form was dominant for verbenone. These indicate the importance of determining the enantiomer composition of volatile components for investigating the physiological and psychological effects on humans. Overall, enantiomeric ratios were determined by volatile components, with no difference between essential oils and hydrosols or between seasons.     

Bark Essential Oil of Cedrelopsis grevei from Madagascar: Investigation of Steam‐Distillation Conditions

The effect of the distillation time on the yield and chemical composition of the bark essential oil of Cedrelopsis grevei Baill. was investigated. Distillation kinetics were determined for three batches of bark sampled from two sites, i.e., Itampolo (batches IT1 and IT2) and Salary (SAL), located in a region in the south of Madagascar with characteristically large populations of C. grevei. The bark samples were subjected to steam distillation, and the essential oil was collected at 3‐h intervals. The total yield (calculated after 14 h of distillation) varied from 0.9 to 1.7%, according to the batch tested. Moreover, the essential oils obtained were characterized by GC‐FID and GC/MS analyses. During the course of the distillation, the relative percentages of the most volatile components (monoterpenes and sesquiterpene hydrocarbons) diminished progressively, whereas the least volatile ones (oxygenated derivatives) increased at a consistent rate. Principal component analysis (PCA) and agglomerative hierarchical clustering analysis (AHC) of the results, performed on 13 principal components, allowed distinguishing three chemical groups, corresponding to the three batches, irrespective of the distillation time. This indicated that the chemical variability currently observed with commercial samples is not mainly linked to the experimental conditions of the extraction process, as the distillation time did not significantly alter the chemical composition of the essential oils.     

Validation of a quantitative assay of arbutin using gas chromatography in Origanum majorana and Arctostaphylos uva‐ursi extracts

Introduction – Arbutin is a skin‐whitening agent that occurs naturally in the bark and leaves of various plants. It is commonly quantified in plant extracts and skin‐whitening products by HPLC. Objective – To develop an alternative gas chromatographic method for the separation and quantification of arbutin in Origanum majorana and Arctostaphylos uva‐ursi extracts. Methodology – N,O‐Bis(trimethylsilyl)acetamide and trimethylchlorosilane were used as silylation reagents, and the gas chromatographic separation of silylated extracts and standards was performed using a DB‐5 narrow bore column. GC‐MS was used for the compound identification, and the quantification was carried out by GC‐FID. The quantitative results were compared with those of HPLC analysis. Results – The developed method gave a good sensitivity with linearity in the range 0.33–500 mg/mL and recovery >98%, allowing the quantification of arbutin in O. majorana and A. uva‐ursi extracts. The relative standard deviations (RSD) relating to intra‐day and inter‐day precision were <0.002% and <4.8%, respectively. The GC results correlated well with those obtained by HPLC analysis. Conclusion – The analysis of marjoram and bearberry samples showed that the established GC method was rapid, selective, and demonstrated that arbutin could be screened alternatively by gas chromatography. Copyright © 2009 John Wiley & Sons, Ltd.     

Essential‐Oil Variability of Juniperus deltoides R.P.Adams along the East Adriatic Coast – How Many Chemotypes Are There?

The composition of the essential oils isolated from twigs of ten Juniperus deltoides R.P . Adams populations from the east Adriatic coast was determined by GC‐FID and GC/MS analyses. Altogether, 169 compounds were identified, representing 95.6–98.4% of the total oil composition. The oils were dominated by monoterpenes (average content of 61.6%), which are characteristic oil components of species of the Juniperus section. Two monoterpenes, α‐pinene and limonene, were the dominant constituents, comprising on average 46.78% of the essential oils. Statistical methods were deployed to determine the diversity of the terpene classes and the common terpenes between the investigated populations. These statistical analyses revealed the existence of three chemotypes within all populations, i.e., a α‐pinene, limonene, and limonene/α‐pinene type.