Chemistry and biological activity of essential oils from Piper claussenianum (Piperaceae)

Analyses of essential oils obtained from fresh and dried leaves and inflorescences of Piper clausenianum were performed using GC-FID, GC-MS and NMR techniques. Forty compounds were detected for these four oils with the total of identified constituents ranging from 88.7% for the dried inflorescences to 97.7% for the dried leaves. Sesquiterpenes were the main constituents in the volatile fraction from leaves with a high percentage of (E)-nerolidol (up to 83%). However, monoterpenes were identified in greater amount in the inflorescences, with linalool percentages from 50% up. The essential oils from fresh leaves and inflorescences were submitted to anti-parasitic activity against a strain of Leishmania amazonensis. Both samples showed biological activity, but the essential oil from P. claussenianum fresh leaves, which was rich in (E)-nerolidol, showed effective growth inhibition of L. amazonensis due to the high percentage of this metabolite in the mixture.     

Evaluation of the chemical composition of Brazilian commercial Cymbopogon citratus (D.C.) stapf samples

The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves), seven presented essential oil concentrations within the threshold established by the Brazilian legislation. The moisture content was also determined and the majority of the samples presented humidity contents near 12%. The GC and GC/MS analyses of the essential oils led to identification of 22 compounds, with neral and geranial as the two major components. The total percentage of these two compounds varied within the investigated sample oils from 40.7% to 75.4%. In addition, a considerable variation in the chemical composition of the analyzed samples was observed. The process of grinding the leaves significantly decreased (by up to 68%) the essential oil content, as well as the percentage of myrcene in the oils.     

Comparison of three different solid-phase microextraction fibres for analysis of essential oils in yacon (Smallanthus sonchifolius) leaves

A headspace solid-phase microextraction (HS-SPME) procedure based on three commercialised fibers (100 microm polydimethylsiloxane, 65 microm polydimethylsiloxane-divinylbenzene and 50/30 microm divinylbenzene-Carboxen-polydimethylsiloxane) is presented for the determination of a selected essential oils in dried leaves of yacon (Smallanthus sonchifolius). The extraction performances of these compounds were compared using fibers with one, two and three coatings. The optimal experimental procedures for the adsorption and desorption of target compounds were determined. Significant parameters affecting sorption process such as sample weight, sorption and desorption time and temperature were optimised and discussed. Finally, the optimised procedures were applied successfully for the determination of these compounds in various yacon species. The relative concentration factors of three characteristic components of yacon were measured for relative evaluation of the fiber efficiency. Main essential oils were isolated from dried yacon leaves by appropriate solid-phase microextraction fiber and semi-quantitative analysis of the target volatiles was conducted by gas chromatography-flame ionisation detection (GC-FID) using a capillary column. Three compounds--beta-pinene, caryophylene and y-cadinene were found as the predominant essential oils. Its relative content was important for specification of yacon varieties. Solid-phase microextraction in combination with gas chromatography enabled a rapid and simple determination of relative content of essential oils in yacon.     

Comparison of solid-phase and single-drop microextractions for headspace analysis of herbal essential oils

The analytical microextraction methods of gas chromatography coupled with flame ionisation detector (GC-FID) for determination of selected essential oils in herbs were proposed. Two microextraction methods for the isolation of essential oils from plants such as Lavandula spica L., Melissa officinalis L., Mentha piperita L. and Salvia officinalis L. were used. The methods of solid-phase and single-drop microextractions, were optimised and compared. The obtained LOD values for all studied essential oils were found to be within 2.5–20.5 μg for SDME and 57.0–139.8 μg for SPME method per 100 g of dried sample leaves. The appropriate LOQ values were then 8.4–68.4 μg for SDME and 189.8–466.1 μg for SPME of target analytes per 100 g of dried sample leaves.      

Drying Effects on Chemical Composition and Antioxidant Activity of Lippia thymoides Essential Oil,a Natural Source of Thymol

Leaves of Lippia thymoides (Verbenaceae) were dried in an oven at 40, 50 and 60 °C and the kinetic of drying and the influence of the drying process on the chemical composition, yield, and DPPH radical scavenging activity of the obtained essential oils were evaluated. The composition of the essential oils was determined with gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses. The influence of drying on the chemical composition of the essential oils of L. thymoides was evaluated by multivariate analysis, and their antioxidant activity was investigated via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The Midilli model was the most appropriate to describe the behavior of drying kinetic data of L. thymoides leaves. Thymol was the major compound for all analyzed conditions; the maximum content was obtained from fresh leaves (62.78 ± 0.63%). The essential oils showed DPPH radical scavenging activity with an average of 73.10 ± 12.08%, and the fresh leaves showed higher inhibition (89.97 ± 0.31%). This is the first study to evaluate the influence of drying on the chemical composition and antioxidant activity of L. thymoides essential oils rich in thymol.     

阔叶箬竹叶和箬竹叶中挥发油的提取及成分分析

采用水蒸气蒸馏法分别提取阔叶箬竹叶和箬竹叶中的挥发油,用乙醚作溶剂进行多次萃取,利用气相色谱-质谱(GC-MS)联用分析二者的化学成分并进行比较。从阔叶箬竹叶提取的挥发油中共鉴定出37种化合物,主要成分为叶醇、1-己醇、苯甲醇、己醛、2-乙基呋喃、β-紫罗兰酮等。从箬竹叶提取的挥发油中共鉴定出49种化合物,主要成分为叶醇、苯甲醇、β-紫罗兰酮、2-己烯醛、苯乙醇、2-甲氧基-4-乙烯基苯酚、2-乙基呋喃等。两种箬叶挥发油中相对含量最高的成分都为叶醇,都含有酮、醛、醇、酚、酯类化合物,且酮、醛、醇的含量明显高于其他成分。     

Chemical composition and anti-inflammatory activities of the essential oils from Acacia mearnsii de Wild

The volatile oils of the leaves and the stem bark of Acacia mearnsii de Wild obtained by hydro-distillation were analysed by gas chromatography–mass spectrometry. A total of 20, 38, 29 and 38 components accounted for 93.8%, 92.1%, 78.5% and 90.9% of the total oils of the fresh, dry leaves and fresh, dry stem bark, respectively. The major components of the oil were octadecyl alcohol (25.5%) and phytol (10.5%); cis-verbenol (29.5%); phytol (10.1%) and phytol (23.4%) for the fresh leaves, dried leaves, fresh stem, dry stem bark, respectively. Oral administration of essential oils at a dose of 2% showed significant (p < 0.05) anti-inflammatory properties in the albumin-induced test model in rats. Oils from the fresh leaves and dry stems inhibited inflammation beyond 4 h post treatment. The potent anti-inflammatory activity of essential oils of A. mearnsii hereby confirmed its traditional use in treating various inflammatory diseases.     

Rapid analysis of the essential oils from dried Illicium verum Hook. f. and Zingiber officinale Rosc. by improved solvent-free microwave extraction with three types of microwave-absorption medium

A new method of extracting essential oils from dried plant materials has been studied. By adding a microwave-absorption medium (MAM) to a reactor, solvent-free microwave extraction (SFME) was improved and can be used to extract essential oils from dried plant material without pretreatment. With a microwave irradiation power of 85 W it took only approximately 30 min to extract the essential oils completely. The whole extraction process is simple, rapid, and economical. Three types of MAM, iron carbonyl powder (ICP), graphite powder (GP), and activated carbon powder (ACP), and two types of dried plant material, Illicium verum Hook. f. and Zingiber officinale Rosc., were studied. The results were compared with those obtained by use of conventional SFME, microwave-assisted hydrodistillation (MAHD), and conventional hydrodistillation (HD), and the conclusion drawn was that improved SFME was a feasible means of extracting essential oils from dried plant materials, because there were few differences between the composition of the essential oils extracted by improved SFME and by the other methods.     

Variability of essential oils of Betonica officinalis (Lamiaceae) from different wild populations in Kosovo

The aerial parts and roots of Betonica officinalis were collected from three localities characterized by different ecological conditions to study the natural variability of the chemical composition of the essential oils in this plant. The leaves and inflorescences were collected during the flowering time, whereas the roots were collected at the end of the vegetative period. The plant material was dried at room temperature. The essential oils were obtained by micro-steam hydrodistillation and analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Overall, 69 constituents were identified in all localities and plant parts. The main compositions of the leaves in all localities were alpha-pinene, 1-octen-3-ol, beta-bourbonene, (E)-caryophyllene and germacrene D. The essential oil of the inflorescences was characterized by these main constituents: alpha-pinene, (E)-caryophyllene and trans-beta-farnesene. In all localities, the percentages of alpha-pinene and (E)-caryophyllene were higher in the inflorescences than in the leaves, whereas nonane was the main constituent in the roots.     

Volatile components from Anthriscus sylvestris (L.) Hoffm

The volatile components of fresh leaves and roots from Anthriscus sylvestris (L.) Hoffm., obtained through hydrodistillation, were analysed by GC and GC-MS. This was compared to dichloromethane extracts of both fresh and dried leaf and root material. The monoterpene fraction (69-70%) dominated, while beta-phellandrene (39-45%) was the main component in both the leaf and the root oil. Other components in the leaf oil were beta-myrcene (17%), sabinene (6.2%), Z-beta-ocimene (5.4%) and benzene acetaldehyde (4.1%). In the roots we found Z-beta-ocimene (16.9%) and alpha-pinene (4.6%) as other major components. These principle constituents of both essential oils were also present in the dichloromethane extracts of the fresh and dried leaves and the roots, although in much smaller percentages. Comparing hydrodistillation of fresh plant material with a dichloromethane extract, the latter yielded a considerably lower amount of constituents. In addition, air drying and freeze drying resulted in a significant loss of volatile constituents as compared to fresh material (dichloromethane extract).     

Quantitative and physical evaluation of patchouli essential oils obtained from different sources of Pogostemon cablin

Patchouli essential oil can be obtained from fresh, dried and fermented plant material. It is a highly valuable product in the fragrance industry and its quality changes depending upon raw material age and oil storage. In this work, patchouli essential oils derived from different treatments have been subjected to GC-FID quantitative analysis using an internal standard (ISTD) method with response factors (RF). Samples were obtained from i) fresh plants; ii) hydrodistillation of one year mature and fermented plants; iii) hydrodistillation of one year mature plants; iv) commercial products from Indonesia and Malaysia. Linear Retention Indices (LRI) for both polar and non-polar GC-MS analyses were also measured as a tool for qualitative analysis towards a homologous series of C7-C30 n-alkanes. The results obtained confirmed that, in all samples, patchouli alcohol was the main volatile constituent, with higher amount in lab-scale produced oils, compared with commercial samples. Other major compounds, in lab oils and commercial samples respectively, were: delta-guaiene, alpha-guaiene, pogostol, seychellene and alpha-patchoulene. Another 36 compounds were also found.     

Chemical variability in the essential oil of Cinnamomum tamala L. leaves from India

The chemical composition of the essential oils obtained from the fresh leaves of Cinnamomum tamala Nees et Eberm. was determined by GC and GC-MS. The yield of the oil on a dry weight basis ranged from 1.2% to 3.9% (w/w). Phenyl propanoids constitute the major portion (88.9-95.0%) of the oils. Fifty-four compounds were identified from the oils. Eugenol (91.4-41.8%) was the main compound, followed by eugenyl acetate (0.0-47.1%) and α-phellandrene (0.6-2.5%) in the analysed oils.     

Acaricidal activity against Tetranychus urticae and essential oil composition of four Croton species from Caatinga biome in northeastern Brazil

Volatile components of essential oils from the leaves and stems of Croton jacobinensis, C. rhamnifolius, C. muscicapa and C. micans, which are medicinal plants found in the Caatinga biome of northeastern Brazil, were analyzed using GC and GC/MS. The acaricidal activity of these oils against Tetranychus urticae was evaluated using the fumigation method. Oil yields from the Croton species ranged from 1.1 +/- 0.0 to 0.6 +/- 0.0%, w/w, for leaves and 0.7 +/- 0.0 to 0.1 +/- 0.0% for stems. Sesquiterpenoids were dominant in all oils, except the stem oil from C. rhamnifolius, which exhibited a high monoterpene content, and the leaf and stem oils from C. muscicapa, which were rich in phenylpropanoids. The major volatile components of the leaf and stem oils from C. jacobinensis were (Z)-alpha-atlantone (24.3 +/- 0.4%) and trans-isolongifolanone (22.8 +/- 0.5%), respectively. The most abundant constituents detected in C. rhamnifolius were alpha-cedrene epoxide (23.3 +/- 0.1%) and caryophyllene oxide (21.9 +/- 0.0%) in the leaf oil, and camphor (16.6 +/- 0.5%) and tricyclene (12.8 +/- 0.1%) in the stem oil. Foenicolin was the main compound identified in the leaf (50.6 +/- 0.2%) and stem (72.7 +/- 0.6%) oils of C. muscicapa, while alpha-bulnesene (32.9 +/- 0.2%) and guaiol (17.9 +/- 0.7%) were the principal components of C. micans oils. These oils exhibited a high degree of toxicity in the fumigation assay. The stem oils from C. jacobinensis and C. rhamnifolius exhibited high lethality rates, with LC50 values of 0.3 and 0.2 microL/L of air after 24 h, respectively. The results suggest the potential use of stem essential oil, especially from C. rhamnifolius and C. jacobinensis, for the integrated control of Tetranychus urticae.     

Sage,Salvia officinalis L., Constituents,Hepatoprotective Activity,and Cytotoxicity Evaluations of the Essential Oils Obtained from Fresh and Differently Timed Dried Herbs: A Comparative Analysis

Sage, Salvia officinalis L., is used worldwide as an aromatic herb for culinary purposes as well as a traditional medicinal agent for various ailments. Current investigations exhibited the effects of extended dryings of the herb on the yields, composition, oil quality, and hepatoprotective as well as anti-cancer biological activities of the hydrodistillation-obtained essential oils from the aerial parts of the plant. The essential oils’ yields, compositions, and biological activities levels of the fresh and differently timed and room-temperature dried herbs differed significantly. The lowest yields of the essential oil were obtained from the fresh herbs (FH, 631 mg, 0.16%), while the highest yield was obtained from the two-week dried herbs (2WDH, 1102 mg, 0.28%). A notable decrease in monoterpenes, with increment in the sesquiterpene constituents, was observed for the FH-based essential oil as compared to all the other batches of the essential oils obtained from the different-timed dried herbs. Additionally, characteristic chemotypic constituents of sage, i.e., α-pinene, camphene, β-pinene, myrcene, 1, 8-cineole, α-thujone, and camphor, were present in significantly higher proportions in all the dried herbs’ essential oils as compared to the FH-based essential oil. The in vivo hepatoprotective activity demonstrated significant reductions in the levels of AST, ALT, and ALP, as well as a significant increase in the total protein (p < 0.05) contents level, as compared to the acetaminophen (AAP) administered experimental group of rats. A significant reduction (p < 0.05) in the ALT level was demonstrated by the 4WDH-based essential oil in comparison to the FH-based essential oil. The levels of creatinine, cholesterol, and triglycerides were reduced (p < 0.05) in the pre-treated rats by the essential oil batches, with non-significant differences found among them as a result of the herbs dryings based oils. A notable increase in the viability of the cells, and total antioxidant capacity (TAOxC) levels, together with the reduction in malondialdehyde (MDA) levels were observed by the essential oils obtained from all the batches as compared with the AAP-treated cell-lines, HepG-2, HeLa, and MCF-7, that indicated the in vitro hepatoprotective effects of the sage essential oils. However, significant improvements in the in vivo and in vitro hepatoprotective activities with the 4WDH-based oil, as compared to all other essential oil-batches and silymarin standard demonstrated the beneficial effects of the drying protocol for the herb for its medicinal purposes.     

Composition of the essential oil of Salvia officinalis L. from various European countries

Variations in the essential oil composition of Salvia officinalis L. growing in Estonia and in other European countries were determined. The oils were obtained in yields of 2.2-24.8 mL kg(-1). In three samples, the content of essential oil did not conform to the EP standard (10 mL kg(-1)). Variations in the essential oil composition of sage were studied using capillary gas chromatographic methods. A total of 40 components were identified. The principal components in the sage oils were 1,8-cineole, camphor, alpha-thujone, beta-thujone, borneol, and viridiflorol. The chemotypes of sage were not determined in investigated samples. The concentration of the main compounds in the drugs cultivated in Estonia varied in about the same range as the concentrations of these compounds in the oils of drugs obtained from other countries. The comparatively high concentration of toxic thujones seem to be characteristic to sage leaves cultivated in Estonia.     

Chemical composition,antioxidant and antimicrobial potential of essential oils from different parts of <Emphasis Type="Italic">Daphne mucronata</Emphasis> Royle

This research work was executed to determine chemical composition, anti-oxidant and anti-microbial potential of the essential oils extracted from the leaves and stem of Daphne mucronata Royle. From leaves and stem oils fifty-one different constituents were identified through GC/MS examination. The antioxidant potential evaluated through DPPH free radical scavenging activity and %-inhibition of peroxidation in linoleic acid system. The stem’s essential oil showed the good antioxidant activity as compared to leaves essential oil. Results of Antimicrobial activity revealed that both stem and leaves oils showed strong activity against Candida albicans with large inhibition zone (22.2?±?0.01, 18.9?±?0.20 mm) and lowest MIC values (0.98?±?0.005, 2.44?±?0.002 mg/mL) respectively. Leaves essential was also active against Escherichia coli with inhibition zone of 8.88?±?0.01 mm and MIC values of 11.2?±?0.40 mg/mL. These results suggested that the plant’s essential oils would be a potential cradle for the natural product based antimicrobial as well as antioxidant agents.

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Occurrence and prevention of isomerization of some monoterpene hydrocarbons from essential oils during liquid-solid chromatography on silica gel

Summary During LSC of naturally occurring monoterpene hydrocarbon mixtures from essential oils using silica gel as adsorbent alterations in the composition of the mixtures were observed by means of gas chromatography. Impurities (metals) and active sites on dried silica gels were found to be responsible for a series of isomerizations of a number of the constituents. After purification by washing the silica gel with acid and base and after deactivation of the dried silica gel by adding water (5%) the isomerization processes could be avoided. This was tested by means of the monoterpene hydrocarbon mixtures of three essential oils and a number of pure monoterpene hydrocarbons.     

Chemical composition, and antioxidant and antimicrobial activities of essential Oil of Phyllostachys heterocycla cv. Pubescens varieties from China

The essential oils of Phyllostachys heterocycla cv. Pubescens, Phyllostachys heterocycla cv. Gracilis, Phyllostachys heterocycla cv. Heterocycla and Phyllostachys kwangsiensis leaves were obtained by steam distillation. Their chemical components were separated and identified by gas chromatography/mass spectrometry (GC/MS). Meanwhile, the effect of scavenging free radicals of essential oil was assayed by using the DPPH·method with Trolox? as control to evaluate their antioxidant capacities. Gram-positive (Staphyloccocus aureus) and Gram-negative (Escherichia coli) were selected as the indicator microorganisms to evaluate the antimicrobial activity. Antimicrobial properties were estimated by the agar diffusion method. The results show that 63 components were separated and identified by GC/MS from these varieties of bamboo leaves. cis-3-Hexenol, whose content in cv. Pubescens, Gracilis, Heterocycla and Ph. kwangsiensis was 27.11%, 24.62%, 30.51% and 34.65%, respectively, was the main constituent. The relative content of alcohol compounds in these varieties of essential oils ranged from 39.8% to 46.64%. All of the bamboo leaf essential oils possessed certain antioxidant capacity; the corresponding IC?? values were 3.1622, 4.9353, 4.2473, and 5.4746 μL/mL, respectively. Essential oils of all tested bamboo spp. were active against Staphylococcus epidermidis and E. coli, showing a positive correlation with the essential oil concentration of 50.42-300 μL/mL. The results indicated there were no significant differences among three varieties and the related species with respect to their antioxidant and antimicrobial activities. This paper provides evidence for studying the essential composition from different varieties of bamboo leaves.     

Composition and chemical variability of leaf oil of Myrtus communis from north-eastern Algeria

The chemical composition of 27 oil samples of Myrtus communis isolated from leaves collected in three locations in north-eastern Algeria was investigated by GC(RI) and 13C NMR spectroscopy. Yields ranged between 0.2-1.2% (w/w). The chemical composition of the oils was largely dominated by monoterpene hydrocarbons, with alpha-pinene (40.5-64.0%), 1,8-cineole (10.9-29.1%) and limonene (6.7-8.2%) being the major compounds. In all the samples, 3,3,5,5,8,8-hexamethyl-7-oxabicyclo[4.3.0]non-1(6)-ene-2,4-dione was identified (0.8-1.5%). The composition is similar to that reported for myrtle oils from Corsica, Sardinia and Tunisia, but differed from that of Moroccan and Spanish myrtle oils.     

Extraction of essential oils from Algerian myrtle leaves using instant controlled pressure drop technology

In the present work, the new extraction process of Détente Instantanée Contrôlée DIC (French, for instant controlled pressure drop) was studied, developed, quantitatively and qualitatively compared to the conventional hydrodistillation method for the extraction of essential oils from Algerian myrtle leaves. DIC was used as a thermomechanical treatment, DIC subjecting the product to a high-pressure saturated steam. The DIC cycle ends with an abrupt pressure drop towards vacuum, and this instantly leads to an autovaporization of myrtle volatile compounds. An immediate condensation in the vacuum tank produced a micro-emulsion of water and essential oils. Thus, an ultra-rapid cooling of residual leaves occurred, precluding any thermal degradation. An experimental protocol was designed with 3 independent variables: saturated steam pressure between 0.1 and 0.6 MPa, resulting in a temperature between 100 and 160 °C, a total thermal processing time between 19 and 221 s, and between 2 and 6 DIC cycles. The essential oils yield was defined as the main dependent variable. This direct extraction gave high yields and high quality essential oil, as revealed by composition and antioxidant activity (results not shown). After this treatment, the myrtle leaves were recovered and hydrodistilled in order to quantify the essential oil content in residual DIC-treated samples. Scanning electron microscope (SEM) showed some modification of the structure with a slight destruction of cell walls after DIC treatment.