Comparative seasonal variation and chemical composition of essential oils from the leaves and stems of Schefflera heptaphylla using microwave-assisted and conventional hydrodistillation

Two different isolation techniques, microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD), were used to extract the volatile constituents from the leaves and stems of Schefflera heptaphylla (L.) Frodin harvested during four different seasons, which were subsequently analyzed via gas chromatography with flame ionization detection and gas chromatography with mass spectrometry. MAHD is more advantageous than HD in terms of energy savings and extraction time (60 min vs. 180 min for MAHD vs. HD). Large variations in the composition among the different oils were observed. The seasonal changes in the percentages of the main constituents of the oils were irregular; this affected the quantity and composition of the oil. Oil yield was affected by the method of extraction and seasonal changes. It ranged from 0.11% to 0.27%, with the maximum amount of oil extracted from the leaves using MAHD in winter and the minimum from the stem oil extraction using HD in spring. The essential oil content varied significantly with the season. Sesquiterpene hydrocarbons constituted the major portion of the essential oils. Sesquiterpene hydrocarbons were highest in the leaf oil extraction by HD during winter (88.6%) and lowest in the stem oil extraction by HD during spring (56.3%). Microwave irradiation did not adversely affect the composition of the essential oils. MAHD, indeed, is a modern, green, and fast technology.     

无溶剂微波提取法提取柚皮精油的初步研究

以柚类果实的外果皮为试材利用自制的微波结合重力萃取装置提取柚皮精油比较了无溶剂微波法 与水蒸馏法提取精油的效果结果表明2 种方法提取250 g 柚皮的精油量均在0.40 mL 左右无溶剂微波法提取可 节省时间90%以上节能60%气相色谱分析表明,无溶剂微波法与蒸馏法提取精油的成分基本相同,表明无溶剂微 波提取基本不影响柚皮精油的质量。     

Bioactive and Fragrant Constituents of Artemisia sieberi Besser Grown on Two Different Soil Types in Central Iran

The dried leaves and aerial parts of Artemisia sieberi Besser, which belongs to the Asteraceae family (Anthemideae) and grows in central Iran, were hydrodistilled to produce essential oils. The oil concentrations of the leaves and aerial parts were 0.32% and 0.79% (w/w), respectively. The essential oils were analyzed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). The amounts of the samples injected were 1.0 nL (diluted 1.0 μL of sample in 1000 ml of n-pentane, v/v). Twenty-three and 14 bioactive, flavor, and fragrance molecules were identified, representing 99.04% and 99.40% of the aerial parts’ essential oils from sites A and B, respectively. Aerial parts of the plants and the habitat soils were sampled at random in full flowering stages in a completely randomized (CR) design with three replications from two sites with different soil types. The main components were trans-methyl isoeugenol (32.60%) in the first site (A) and β-bisabolene (33.59%) in the second site (B) oils. The compositions of the oils were mostly quantitatively rather than qualitatively different.     

Isolation of volatils from maritime pine sawdust waste by different processes: Ultrasound,microwave, turbohydrodistillation,and hydrodistillation

This study concerns the transformation of maritime pine (Pinus pinaster) sawdust waste into potentially novel products through isolation of volatile compounds in the form of valuable oil. Different techniques, namely, turbohydrodistillation (THD), solvent-free microwave extraction (SFME), microwave hydrodiffusion and gravity (MHG), and ultrasound-assisted extraction (UAE) were tested. These different processes were compared to conventional hydrodistillation (HD) and allowed to extract almost similar yields of isolated oils. THD which consists in a permanent agitation during extraction and UAE improve the kinetics of extraction, but MHG and SFME required the shortest extraction times, 60 min to reach a maximal yield of 0.272 and 0.266% (w/w), respectively. The compositions of isolated oils are almost similar with a high proportion of oxygenated compounds for MHG and SFME, respectively, 56.9% and 54.5% compared with 37.7%, 44.1% and 34.1%, respectively, for THD, UAE, and for the conventional HD method.     

Nutrient solution concentration and collection time in phytomass production,content, yield and chemical composition of essential oil of rosemary

Rosmarinus officinalis L. (rosemary), is a medicinal and aromatic species used in the cosmetics and food processing industries. The present study aimed to evaluate the biomass production, content, yield and chemical composition of the essential oil of rosemary in cultivation out of soil with different concentrations of nutrient solution in both harvests. The cultivation of rosemary was conducted in a protected system off the ground, with concentrations of nutrient solutions of 1, 2, 3, 4 and 5 dS.m^?1 for fertigation with collections of leaves 100 and 160 days after planting. Nutrient solution concentration influences phytomass production and the content and yield of essential oil of rosemary, though not its chemical composition. The collection time does not interfere in the content of essential oil; however, does interfere in the chemical composition; the production of phytomass and the yield of oil per plant are higher in collections at 160 days after planting.     

山东披萨草挥发油化学成分的研究

分别采用微波水蒸气蒸馏法(MHD,微波功率300 W,同液比1:10,蒸馏时间1 h)和水蒸气蒸馏法(HD)提取山东披萨草挥发油,利用气相色谱-质谱(GC/MS)联用技术和保留指数比较法分析了挥发油的化学成分.从MHD法披萨草挥发油中鉴定出42种化合物,占挥发油总量的99.35%,主要成分为香芹酚(67.85%)、麝香...     

Chemical profiling and biological screening of Thymus lotocephalus extracts obtained by supercritical fluid extraction and hydrodistillation

Essential oil and extracts from the aerial parts of Thymus lotocephalus were obtained by hydrodistillation (HD) and supercritical fluid extraction (SFE) in two different collectors, respectively. SFE was conducted at 40 °C and a working pressure of 12 or 18 MPa. The chemical profiles were determined using GC-FID and GC-IT-MS. Oxygen-containing monoterpenes were the primary constituents in the essential oil and SFE extracts collected in the second separator, while the extracts obtained in the first separator were predominantly oxygen-containing sesquiterpenes. A large number of compounds were identified by hydrodistillation and, in contrast, the highest extraction yields were obtained using SFE. Linalool (10.43 ± 1.63%) was the main component in essential oil, whereas camphor (7.91 ± 0.84%) and cis-linalool oxide (7.25 ± 1.45%) were the major compounds in the extracts-2nd separator obtained at pressures of 12 and 18 MPa, respectively. Caryophyllene oxide was the primary constituent identified in the extracts-1st separator (4.34 ± 0.51 and 4.41 ± 1.25% obtained at 12 and 18 MPa, respectively). The antioxidant activity was assessed by ORAC and DPPH assays, and the anti-cholinesterase activity was evaluated in vitro using Ellman's method. The essential oil and SFE extracts (first separator) of T. lotocephalus possessed antioxidant activity and strongly inhibited cholinesterases. We also demonstrated that the acetylcholinesterase and butyrylcholinesterase inhibitory activities of the essential oil could be attributed to 1,8-cineole and caryophyllene oxide, respectively.