Stem Oil Research Articles

Constituents of the stem and root essential oils of Kadsura heteroclita (Roxb.) Craib from Vinh Phuc province

The stem and root essential oils of Kadsura heteroclita (Roxb.) Craib were prepared by steam distillation of fresh materials in a glass for 3h. The essential oils yields were 0.37% and 0.30% from the roots and stems (in absolute dry material), respectively. The stem and root essential oils from Kadsura heteroclita (Roxb.) Craib analyzed by GC and GC/MS showed 26 constituents and 41 constituents identified in the stem and root essential oils, respectively. The major components of the root essential oil of Kadsura heteroclita are: epi-bicyclogermacrene (19.6%), terpinolene-4-ol (13.3%), d-cadinene (8.9%) and spathulenol (7.7%). The major components of the stem essential oil of Kadsura heteroclita are: terpinolene-4-ol (22.4%), bicyclo[4.4.0]dec-1-ene (18.9%), d-cadinene (8.8%), a-cadinol (6.2%) and cadina-1,4-diene (6.0%). Most of major components of root and stem essential oils extracted from Kadsura heteroclita are similar, such as, terpinolen-4-ol (13.3% in roots and 24,4% in stems), d-cadinen (8.9% in roots and 8.8% in stems), a-copaen (3.7% in root and 3.8% in stems), a-cadinol (4.2% in roots and 6.2% in stems). But the major component in the stem oil as epi-bicyclogermacren (19.6%) did not appear in the root oil; while the bicyclo [4.4.0] dec-1-en (18.9%) only found in the root oil of K. heteroclita. The major constituents of the stem essential oils of Kadsura heteroclita (Roxb.) Craib from Vietnam and China are extremely variable.

Chemical composition of the essential oil of Calocedrus macrolepis Kurz from Ha Giang province

The stem oil of Calocedrus macrolepis Kurz collected from Ha Giang province, Vietnam, in May 2008 was isolated by steam distillation to give oil yield 0.15% and analyzed by Capillary GC and GC/MS. Thirty eight components have been identified accounting more than 78.7% of the oil respectively. The major constituents of this oil appeared to be benzoic acid (23.3%) and dodecan-7 ol (14.6%). Less predominant constituents included trimethylenehexane (7.3%), α-terpineol (6.6%), 1,3-cyclooctadiene (5.8%), 4-nitrostyrene (2.8%), undecane (2.7%), methyllenebornane (2.3%), tricyclene (2.3%), tricyclo (2.0%) and cavacrol methyl ther (1.1%). All the other components were in concentration of less than 0.1-0.9%.

Constituents and Antimicrobial Activity of the Essential Oils from Flower, Leaf and Stem of Helichrysum armenium

The chemical constituents from the flower, leaf and stem of Helichrysum armenium DC. (Asteraceae) growing in Iran were obtained by hydrodistillation and analyzed by GC and GC/MS. The oil of flower was characterized by higher amount of limonene (21.2%), alpha-cadinol (18.2%), borneol (11.9%), delta-cadinene (9.0%), bornyl acetate (8.0%) and alpha-humulene (7.3%). Twenty one constituents representing 96.2% of the chromatographical leaf oil were identified of which limonene (29.2%), alpha-pinene (14.4%), caryophyllene oxide (6.5%), alpha-gurjunene (6.3%), bornyl acetate (5.5%) and torreyol (5.2%) were the major components. The main components of the stem oil were limonene (23.6%), alpha-pinene (13.4%), spathulenol (6.4%), alpha-gurjunene (6.3%), caryophyllene oxide (5.3%), bornyl acetate (5.2%), beta-cubebene (4.8%) and delta-cadinene (4.3%). The composition of the oils is different, although the most abundant components are identical in leaf oil (96.2%). The antimicrobial effect of flower, leaf and stem essential oils from Helichrysum armenium was studied according to the agar diffusion cup method. The essential oils had a moderate effect on the Gram-positive and Gram-negative bacteria and had a substantial fungicidal effect on the fungi under study.

Chemical Composition and Antimicrobial Activity of Essential Oils from Scabiosa arenariaForssk. Growing Wild in Tunisia

The essential oils isolated from three organs, i.e., fruits, stems and leaves, and flowers, of the endemic North African plant Scabiosa arenaria Forssk. were screened for their chemical composition, as well as their possible antibacterial, anticandidal, and antifungal properties. According to the GC-FID and GC/MS analyses, 61 (99.26% of the total oil composition), 79 (98.43%), and 51 compounds (99.9%) were identified in the three oils, respectively. While α-thujone (34.39%), camphor (17.48%), and β-thujone (15.29%) constituted the major compounds of the fruit oil, chrysanthenone (23.43%), together with camphor (12.98%) and α-thujone (10.7%), were the main constituents of the stem and leaf oil. In the case of the flower oil, also chrysanthenone (38.52%), camphor (11.75%), and α-thujone (9.5%) were identified as the major compounds. Furthermore, the isolated oils were tested against 16 Gram-positive and Gram-negative bacteria, four Candida species, and nine phytopathogenic fungal strains. It was found that the oils exhibited interesting antibacterial and anticandidal activities, comparable to those of thymol, which was used as positive control, but no activity against the phytopathogenic fungal strains was observed.

Chemical Diversity of Essential Oils from Asteriscus graveolens (Forssk.) Less.: Identification of cis‐8‐Acetoxychrysanthenyl Acetate as a New Natural Component

Asteriscus graveolens is an endemic medicinal plant mainly distributed in south-western Algeria and south-eastern Morocco. The essential oils of leaves, stems, and flowers of A. graveolens had been studied by GC, GC/MS, and (13) C-NMR. The spectral data of two nerolidol derivatives, 6-oxo- and 6-hydroxycyclonerolidol, were reassigned by 1D- and 2D-NMR spectroscopy. These compounds can be considered as chemical markers of this genus. The structure of a monoterpenic diester with a chrysanthenane skeleton, i.e., cis-8-acetoxychrysanthenyl acetate, was determined for the first time on the basis of GC/MS, and 1D- and 2D-NMR. The stem and leaf oils were characterized by high content of oxygenated sesquiterpenes with 6-oxo- and 6-hydroxycyclonerolidol as major components, and the flower essential oils were dominated by the new monoterpenic compound cis-8-acetoxychrysanthenyl acetate.

Essential oil composition and chemical variability of Xanthium italicum Moretti from Corsica

ABSTRACTThe chemical composition of Xanthium italicum Moretti essential oil was established for the first time using gas chromatography and gas chromatography–mass spectrometry. One hundred and seven compounds were identified and accounted for 98.7% of the total amount. The main compounds were limonene (35.3%), borneol (5.6%), sabinene (5.8%), germacrene‐D (2.5%), α‐bisabolol (2.4%) and α‐humulene (2.1%). Twenty‐five oil samples were investigated, and their chemical variability was analysed statistically. Two main groups of essential oils were identified in concordance with the morphological characteristics: hydrocarbon‐rich oils, which correlated with 100–120 cm plant height and oxygenated‐rich oils, which correlated with 5–20 cm plant height. The chemical composition of the oils obtained from separated organs and the concentrations of the main compounds throughout the vegetative cycle of the plant were studied. Stem and leaf oils were characterized by the occurrence of limonene (47.9% g and 22.9%, respectively) and germacrene‐D (4.6% and 15.8%, respectively). Flower oils displayed δ‐selinene and germacrene‐D as the main components (22.4% and 17.0%, respectively). X. italicum fruits yielded oil with a high amount of oxygenated compounds (72.9%), particularly sesquiterpene compounds (61.5%) such as α‐bisabolol (43.0%), α‐cadinol (5.0%) and (E,E)‐α‐farnesol (4.3%). The amount of hydrocarbon compounds remained stable throughout the vegetative cycle, whereas the amounts of oxygenated compounds increased during fructification. Copyright © 2012 John Wiley & Sons, Ltd.

Biological activity and essential oil composition of two new Tanacetum chiliophyllum (Fisch. & Mey.) Schultz Bip. var. chiliophyllum chemotypes from Turkey

Water-distilled essential oils from aerial parts of Tanacetum chiliophyllum (Fisch. & Mey.) Schultz Bip. var. chiliophyllum, from two different localities in Turkey were analyzed by GC and GC/MS. The flower and stem oils of T. chiliophyllum var. chiliophyllum collected from Van-Muradiye location were characterized with camphor (32.5%, 36.2%), 1,8-cineole (1.6%, 16.1%), chamazulene (9.2%, 2.9%), for the first sample from this location and 1,8-cineole (12%, 18.4%), terpinene-4-o1 (10.3%, 9%), (E)-sesquilavandullol (5.8%, 1.6%), p-cymene (5.4%, 5.4%), hexadecanoic acid (4.2%, 7.6%) for the second plant sample. The flower and stem oils of the plant collected from Van-Güzeldere location were characterized with 1,8-cineole (22.1%, 28.9%), terpinene-4-ol (6.5%, 5.6%), α-pinene (5.3%, 1.5%). Five chemotypes were proposed according to biosynthetic origin of the main components of the investigated oils and previous investigations and they were tested with AHC analysis. Antibacterial activity of the oils were evaluated for five Gram-positive and five Gram-negative bacteria by using a broth microdulition assay. The highest activity was observed on Escherichia coli with the stem oil of the first sample from Muradiye (62.5μg/mL) which gave same MIC with the positive control chloramphenicol. The highest DPPH scavenging activity was observed on the stem oil from the first sample of Muradiye location at 15mg/mL concentration (79.1%). The oils showed moderate DPPH scavenging activity when compared with the positive control α-tocopherol. All of the oils except for flower and stem oils from the second sample of Muradiye location showed toxicity against Vibrio fischeri in the TLC-bioluminescence assay.

Essential Oil Composition and Antibacterial Activity of Monticalia greenmaniana (Asteraceae)

The essential oils from fresh aerial parts of Monticalia greenmaniana (Hieron) C. Jeffrey (Asteraceae) collected in March, were analyzed by GC/MS. Oil yields (w/v) of 0.1% (flowers), 0.07%, (stems) and 0.1% (leaves) were obtained by hydrodistillation. Thirteen, sixteen and eighteen components, respectively, were identified by comparison of their mass spectra with those in the Wiley GC-MS Library data base. The major components of the flower and stem oils were 1-nonane (38.8% flowers; 33.5% stems), alpha-pinene (29.0% flowers; 14.8% stems) and germacrene D (15.6% flowers; 18.6% stems). However, in the leaf oil, germacrene D was observed at 50.7%, followed by beta-cedrene at 8.4%. The leaf essential oil showed a broad spectrum of antibacterial activity against the important human pathogenic Gram-positive and Gram-negative bacteria Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Klebsiella pneumoniae (ATCC 25955) with MIC values ranging from 75 to 6000 ppm.

Essential oil content and composition of Achillea biebersteinii Afan. in different plant parts and phenological stages

In this study, the essential oil content and composition of Achillea biebersteinii Afan. at different phenological stages including vegetative, floral budding, full flowering (leaves, stems and flowers) and fruit set were studied by means of gas chromatography (GC) and gas chromatography–mass spectometry (GC–MS). All oil samples from different plant parts and phenological stages were mostly made up of monoterpenoid compounds (88.6 – 99.6%), especially oxygenated ones (52.4 – 82.4%). The oil of the vegetative stage contained high amounts of limonene, 4aα-7β-7aα-nepetalactone, p-cymene and 1,8-cineole. The major constituents in the flower budding stage oil were found to be limonene, 1,8-cineole and 4aα-7β-7aα-nepetalactone. In the oil of the fruit set stage, γ-terpinene, p-cymene and cis-chrysanthenyl acetate were the predominant constituents. On the other hand, the most important compounds from the stem oil were 4aα-7α-7aα-nepetalactone, 1,8-cineole, 4aα-7β-7aα-nepetalactone and camphor. 4aα-7α-7aα-nepetalactone, limonene, 1,8-cineole and cis-p-menth-2-en-1-ol were found in high concentration in the oil of leaves, whereas 4aα-7α-7aα-nepetalactone, 4aα-7β-7aα-nepetalactone, limonene and p-cymene were present in large amounts in the oil of flowers.

Phytochemical and antimicrobial activities of Lavandula officinalis leaves and stems against some pathogenic microorganisms

The leaves and stem-bark of Lavandula officinalis were investigated for activity against some pathogenic organisms. Phytochemical screening revealed the presence of coumarins, tannins, flavonoids, volatile oil and fatty acids. Twenty six and twenty were characterized representing 84.5% (leaf oil) and 91.4% (stem oil) of the lot of components detected. The leaf oil of the major constituents was identified as borneol (23.6%), 1, 8-cineol (17.6%), camphor (12.6%). In the stem oil of plant 1, 8cineol (20.8%), borneol (19.2%), α-cadinol (11.3%), caryophyllene oxide (10.4%) and camphor (7.4%) were the predominating compounds . The hexane extracts of leaf and stem of plant were obtained by soxhlet apparatus. The fatty acids were derived to methyl esters and determined by gas chromatograph and mass spectrometer (GC/MS) systems. The main components of the leaf and stem (hexanic extracts) were ω-3 (43.2 and 21.0%), ω-6 (3.4 and 14.5%), palmitic acid (7.4 and 12.4%) and Bis (2-ethylhexyl) phthalate (12.8 and 16.7%), respectively. Antimicrobial activities of the crude methanol, hexane extracts and essential oil from leaf and stem were evaluated using agar diffusion method. Results, suggest potential antimicrobial activity of the essential oil and extracts of L. officinalis, which may find those application in future research for the food and pharmaceutical industry.

Composition of the Essential Oils and Antibacterial Activities of Hymenocrater yazdianus, Stachys obtusicrena and Nepeta asterotricha Three Labiatae Herbs Growing Wild in Iran

Water-distilled essential oils from leaves of Hymenocrater yazdianus Rech.f., flowers of Stachys obtusicrena Boiss., and stems and flowers of Nepeta asterotricha Rech.f., which are endemic to Iran, were analyzed by GC and GC/MS. Fifty-five components of the leaf oil of H. yazdianus were characterized, representing 95.1% of the total components detected. The major constituents were identified as 1,8-cineole (17.6%), beta-caryophyllene (13.9%), alpha-pinene (10.6%) and caryophyllene oxide (10.4%). Germacrene-D (37.5%) and alpha-bisabolol (23.5%) were the main components among the twenty constituents characterized in the flower oil of S. obtusicrena, representing 90.8% of the total components detected. Thirty-five compounds representing 93.0% of the stem oil of N. asterotrica were identified among which terpinen-4-ol (22.8%) and gamma-terpinene (14.1%) were the major ones. The flower oil of the species was characterized by higher amounts of terpinen-4-ol (24.8%), 4a alpha, 7a beta-nepetalactone (18.2%) and 1,8-cineole (11.6%) among the thirty-three components comprising 98.5% of the total oil detected. The antibacterial activity of the stem, leaf and flower oils of Hymenocrater yazdianus, Stachys obtusicrena and Nepeta asterotricha against seven Gram-positive and Gram-negative bacteria were determined using the MIC method. The growth inhibitory zone (mm) was also measured.

Chemical Composition of the Volatile Oils from the Flowers, Stems and Leaves of Prangos latiloba Korov. Using the Head Space Solid Phase Microextraction Method Prior to Analysis by Gas Chromatography-Mass Spectrometry

The present report deals with the analysis and comparison of composition of the volatiles obtained by head space-solid phase microextraction (HS-SPME) procedures from the crushed dry flowers, leaves and stems of Prangos latiloba Korov. (Umbeliferae). The plant material was collected from south of Sabzevar, Khorasan Razavi Province, Iran. The SPME headspace volatiles were collected using a fiber coated with polydimethylsiloxane (PDMS). The composition of the volatile essential oils was investigated by GCFID and GC-MS. Twenty eight components, representing 86.8 % of the total, were identified in the oil from the flowers, of which the major components were limonene (18.3 %), myrcene (10.4 %), (E)-(3-Ocimene (7.8 %), oc-phellandrene (6.4 %) and α-pinene (5.7 %). Twenty three components (84.6 % of the total) were identified in the leaf oil, the major ones being limonene (17.4 %), myrcene (9.4 %), α-pinene (6.1 %), aphellandrene (5.4 %) and (E)-β-ocimene (5.3 %). Of the 29 constituents were identified (83.7 % of the total) in the stem oil, the main ones were limonene (13.5 %), myrcene (8.6 %), α-phellandrene (4.9 %), germacreneD (4.5 %) and γ-curcumene (4.3 %). A comparison of the chemical composition of volatiles of P. latiloba Korov. from this study with previous studies on the same genus showed variation of the major components. These results imply that although the use of HS-SPME has the advantages of simplicity, solvent-free sampling and lowering the amount of sample needed, it can also affect the results of the essential oils analysis.

Chemical Composition of the Essential Oil from Flowers, Leaves and Stems of Haplophyllum perforatum by Using Head Space Solid Phase Microextraction

The head-space volatiles separated from flowers, leaves and stems of Haplophyllum perforatum, a growing wild plant collected in the Golestan Province of Iran were investigated. A 100 μm polydimethylsiloxane (PDMS) fiber was conditioned to trap the volatiles prior to GC and GC-MS analyses. Sabinene (52.7 %, 24.7 %, and 26.2 %) and trans-carryophyllene (10.8 %, 35.6 %, and 8.8 %) were the main constituents in the flower, leaf, and stem oils of H. perforatum, respectively. The other components in the flower oil of the plant were (2E,6E)-farnesyl aceton (10.3 %), hexadecanoic acid (5.1 %), β-pinene (5.0 %) and cis-sabinene hydrate (4.9 %). Moreover, elemol (17.4 %), α-humulene (4.6 %), α-pinene (4.5 %) and 1,8-cineol (4.3 %) were found in the leave oil as well as camphor (7.4 %), limonene (6.3 %), elemol (5.0 %), β-phellandrene (4.9 %) and α-pinene (4.6 %) in the stem oil. The oils of flower and stem were consisted mainly of monoterpene hydrocarbons while the leave oil was characterized by sesquiterpene hydrocarbons as the main constituents.

Essential Oils Composition from Descurainia sophia L. Leaves and Stems Growing Wild in North of Iran

The essential oils obtained by hydrodistillation from the leaves and stems of Descurainiasophia L. were analysed by GC and GC-MS, separately. The main components of the leave and stem oils wererelatively similar and included hexahydrofarnesyl acetone, (E)-ocimen, phytol, methyl linolenate, α-cedrol,(Z)-caryophyllene and β-ionone. The essential oils consisted mainly of sesquiterpenoids (39.65 % for leavesand 39.46 % for stems).

Chemical Composition of the Leaf, Stem and Root Oils of Pleiospermium alatum

The essential oils obtained by hydrodistillation of leaves, stem and roots of Pleiospermium alatum were analyzed by Gas Chromatography and Gas Chromatography—Mass Spectrometry. Thirty-one components comprising 97.3% of the leaf oil, twenty-nine components comprising 96.1% of the stem oil and twenty-three components comprising 95.0% of the root oil were identified. The major components in the leaf oil were elemol (12.5%) followed by pregei- jerene (10.5%), α-cadinol (8.5%) and geijerene (8.5%). The stem oil contained elemol (12.4%), α-cadinol (11.1%) and epi-a-muurolol (9.4%) as the major components, while the root oil had α-cadinol (27.9%), α-bisabolol (11.5%), α-santalene (11.0%) and elemol (9.8 %) as the major components.

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 (60min vs. 180min 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.

Antibacterial Activity and GC/MS Analysis of the Essential Oils from Flower, Leaf and Stem of Origanum vulgare ssp. viride Growing Wild in Northwest Iran

Essential oils obtained from flowers, leaves and stems of Origanum vulgare L. ssp. viride (Boiss.) Hayek., growing wild in Ardabil Province (north-west Iran), were analyzed by GC and GC/MS. beta-Caryophyllene was the major constituent in all three oils (48.1%, 50.1% and 60.2%, respectively). Of the 19 components detected in the flower oil, comprising 96.3% of the total, the major components were 1,8-cineole (11.6%), alpha-pinene (6.9%), and gamma-cadinene (4.8%). 1-Octen-3-ol (23.8%), and 1,8-cineole (8.5%) predominated in the leafoil. In the stem oil, other main constituents were bicyclogermacrene (9.8%), 1,8-cineole (6.4%), borneol (5.1%), and pinocarvone (4.4%). The essential oils were evaluated for their antibacterial activity against 10 selected microorganisms. The data obtained contribute to the future use of certain essential oils as natural preservatives for food products, due to their safety and positive effect on shelf life.

Composition and antimicrobial activity of essential oil from the aerial part of Artemisia annua

Artemisia annua is widely used as a key component of traditional Chinese medicine in China. The components of the essential oil extracted by hydro distillation from the stems and spikes of A. annua were identified using chromatography–mass spectrometry(GC/MS). The stem oil was composed of 50 components, while the spike oil contained 41 components. 30 compounds were found in both oils. 18 unreported compounds were Piperitone, Octanal and 1,4-Diphenyl-2- butanone etc. From the spike oil the relative content of terpenoids was higher than that from the stem oil. The antimicrobial activity of the spike oil was more active than that of the stem oil. Antimicrobial properties of the plant in Qingyang in China to Escherichia coli and Staphylococcus aureus may be stronger than those in Marseilles in France. Key words: Artemisia annua, essential oil, aerial part, chromatography–mass spectrometry, antimicrobial activity.

Composition of the Essential Oils from Anthriscus cerefolium var. trichocarpa and A. caucalis Growing Wild in the Urban Area of Vienna (Austria)

The composition of the essential oil from the different above ground plant parts of Anthriscus cerefolium and A. caucalis collected in the urban area of Vienna has been studied. The essential oils of A. cerefolium were dominated by estragole (= methylchavicol) and 1-allyl-2,4-dimethoxybenzene, occurring in various proportions. The oils from young flowering plants had more estragole than 1-allyl-2,4-dimethoxybenzene. Fruits from one location reached 95% estragole in the essential oil. In A. caucalis, the main compound of all oils was cis-chrysanthenyl acetate (up to 74%) followed by cis-chrysanthenol (up to 16%). The fruit oils displayed a higher proportion of cis-chrysanthenyl acetate than the leaf or stem oils.

Composition of the essential oil constituents from leaves and stems of Korean Coriandrum sativum and their immunotoxicity activity on the Aedes aegypti L.

The leaves and stems of Coriandrum sativum were extracted and the essential oil composition and immunotoxicity effects were studied. The analyses were conducted by gas chromatography–mass spectroscopy (GC-MS), which revealed the essential oils of C. sativum leaves and stems. Thirty-nine components representing 99.62% of the total oil were identified from the leaves. The major components are cyclododecanol (23.11%), tetradecanal (17.86%), 2-dodecenal (9.93%), 1-decanol (7.24%), 13-tetradecenal (6.85%), 1-dodecanol (6.54%), dodecanal (5.16%), 1-undecanol (2.28%), and decanal (2.33%). Thirty-eight components representing 98.46% of the total oil were identified from the stems of the coriander. The major components are phytol (61.86%), 15-methyltricyclo[6.5.2(13,14),0(7,15)]-pentadeca-1,3,5,7,9,11,13-heptene (7.01%), dodecanal (3.18%), and 1-dodecanol (2.47%). The leaf oil had significant toxic effects against the larvae of Aedes aegypti with an LC50 value of 26.93 ppm and an LC90 value of 37.69 ppm and the stem oil has toxic effects against the larvae of A. aegypti with an LC50 value of 29.39 ppm and an LC90 value of 39.95 ppm. Also, the above data indicate that the major compounds may play an important role in the toxicity of essential oils.