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.     

Characterisation of volatile organic compounds in stemwood using solid-phase microextraction

Solid-phase microextraction (SPME), hydrodistillation and dynamic headspace combined with GC and GC-MS were applied and compared for the analysis of volatile organic compounds (VOCs) from coniferous wood. The SPME conditions (type of fibre, size of wood sample, temperature and exposure time) were optimised, and more than 100 VOCs and semi-volatile compounds extracted and identified from the sapwood and heartwood of Norway spruce (Picea abies). The total number of mono- and sesquiterpenes eluted and identified was similar for the SPME and hydrodistillation methods, but more semi-volatile compounds were released by hydrodistillation. By applying dynamic headspace at room temperature, it was possible to analyse only the most volatile compounds. The qualitative composition of VOCs was similar in spruce sapwood and heartwood, although Z-beta-ocimene occurred only in sapwood while fenchol was present only in heartwood. SPME sampling coupled with GC, applied here to the analysis of VOCs released from stemwood of firs for the first time, is a convenient, sensitive, fast, solvent-free and simple method for the determination of wood volatiles. The technique requires much smaller sample amounts compared with hydrodistillation, and the total amount of VOCs extracted and identified is higher than that obtained by hydrodistillation or dynamic headspace. The relative ratios of the main mono- and sesquiterpenes and -terpenoids were similar using the SPME-GC and hydrodistillation methods.     

Profiling of Compositions of Essential Oils and Volatiles of Salvia limbata Using Traditional and Advanced Techniques and Evaluation for Biological Activities of Their Extracts

In the present work, the essential oils and volatiles from flowers, leaves, and stems of Salvia limbata obtained using microwave‐assisted hydrodistillation, solvent‐free microwave extraction, headspace‐assisted analysis, and headspace‐solid phase microextraction have been characterized for the first time. The results have been also compared with those from traditional separation techniques involving hydrodistillation and steam distillation. Regardless of some common compounds in all of the profiles, some dissimilarities were noted due to the use of different extracting approaches. Taking into account the chemical categories, sesquiterpene hydrocarbons were found as the most represented group of natural compounds contributing to the chemical profiles. It was also noted that the methanol extracts obtained from the flowers of Sal. limbata showed a desirable antioxidant activity, comparable to the standard antioxidant butylated hydroxytoluene. Furthermore, using the disc diffusion and broth microdilution methods, all the tested bacteria demonstrated weak to moderate and moderate to strong sensibilities to the MeOH extracts obtained from different plant parts of Sal. limbata.     

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.     

花椒挥发油的超临界CO2萃取法与水蒸气蒸馏法提取的比较

采用超临界萃取法与水蒸气蒸馏法从花椒中提取花椒挥发油,用GC—MS方法测定各种提取方法得到挥发油的化学成分及相对含量。结果表明,水蒸气提取挥发得率为3．8％（W／W）,主要成分为柠檬烯（22．75％）、沉香醇（21．70％）、罗勒烯（3,7-二甲基-1,3,7-辛三烯）（14．27％）等。超临界CO2萃取法挥发油得率为5．9％（W／W）,主要成分为柠檬烯（14．01％）、沉香醇（13．18％）、罗勒烯（3,7-二甲基-1,3,7-辛三烯）（26．23％）等。两种方法所得到的挥发进行比较,水蒸气蒸馏法分离法得到的挥发油中分离出78个峰,其中含量和相似度高的成分有31种,占86．31％。超临界CO2萃取法提取的花椒挥发油中分离出了152个峰,含量和相似度高的成分有36种,占74．72％。两种提取方法所得到的主要挥发油中有27种成分相同。     

小蓬草精油的提取及GC-MS分析

水蒸馏和水蒸气蒸馏分别提取鲜小蓬草精油的气相色谱-质谱分析结果表明:水蒸馏提取的鲜小蓬草精油挥发性组分较多且柠檬烯质量分数最高(15.36%),香芹酮(10.15%)次之.而水蒸气蒸馏分别提取鲜和干小蓬草精油的气相色谱-质谱分析表明干小蓬草有利于提取更多精油香料成分,且柠檬烯质量分数最高(57.68%),反式-α-佛手...     

五种柏科植物挥发油成分的GC-MS分析

柏科植物是园林绿化中常用的常绿树种,具有种数多、分布广的特点。该研究采用水蒸气蒸馏法提取5种柏科植物叶片中的挥发油,利用气相色谱-质谱(GC-MS)与计算机检索联用技术对其化学成分进行分析和鉴定,并用面积归一法测定各组分的相对含量。结果表明:用水蒸气蒸馏法提取柏科植物挥发油得油率较高,除偃柏外4种柏树的得油率都在0.5%以上;5种柏科植物挥发油中共检测出了80种萜类物质,其中日本花柏中萜类物质最多含有54种,日本扁柏次之含有51种,柏木含有47种,线柏含有42种,偃柏则只含有35种;挥发油中含量较高的成分有乙酸龙脑酯、α-蒎烯、3-蒈烯、D-柠檬烯、松油烯-4-醇、桧烯和萜品油烯等,一些植物还含有龙脑、β-月桂烯、石竹烯、β-紫罗兰酮和Verticiol等一些重要的药用成分;柏科植物挥发油具有成分及相对含量差异大、成分较简单、化合物种类以萜烯类为主的特点。研究结果可为进一步开发利用柏科植物资源提供理论依据。