Bioactivity of essential oil of Litsea cubeba from China and its main compounds against two stored product insects

During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oil of Litsea cubeba fruits was found to possess strong contact toxicity against the cigarette beetle Lasioderma serricorne adults and the booklouse Liposcelis bostrychophila, with LD₅₀ values of 27.33 μg/adult and 71.56 μg/cm², respectively, and also showed strong fumigant toxicity against the two stored product insects with LC₅₀ values of 22.97 and 0.73 mg/L, respectively. The essential oil obtained by hydrodistillation was investigated by GC MS. The main components of the essential oil were identified to be E-citral (geranial) (27.49%), Z-citral (neral) (23.57%) and d-limonene (18.82%) followed by β-thujene (3.34%), β-pinene (2.85%), α-pinene (2.57%), 6-methyl-5-hepten-2-one (2.40%) and linalool (2.36%). Citral (Z/E-citral), d-limonene, β-pinene, α-pinene and linalool were separated and purified by silica gel column chromatography and preparative thin layer chromatography, and further identified by means of physicochemical and spectrometric analysis. Citral and linalool showed strong contact toxicity against L. serricorne and L. bostrychophila (LD₅₀ = 11.76, 12.74 μg/adult and 20.15, 99.97 μg/cm², respectively) and fumigant toxicity against L. serricorne and L. bostrychophila (16.54, 18.04 mg/L air and 0.14, 0.71 mg/L air, respectively). Otherwise, citral, d-limonene and linalool were strongly repellent against the cigarette beetle L. serricorne as the essential oil whereas β-pinene and α-pinene exhibited weaker repellency against the cigarette beetle compared with the positive control, DEET. Moreover, except α-pinene and linalool, the other three compounds as well as the essential oil exhibited comparable repellency against the booklouse relative to DEET.     

Changes in volatile constituents of Zingiber officinale rhizomes during storage and cultivation

The essential oil from the fresh rhizome of Zingiber officinale was characterized by the presence of acyclic oxygenated monoterpenes mainly composed of neral, geraniol, geranial and geranyl acetate. During storage the content of neral and geranial in the rhizome increased to ca 60% of the essential oil, while the content of geraniol and geranyl acetate decreased to an undetectable amount. The change resulted from the conversion of geranyl acetate into geraniol, geranial and neral, successively. The content of geranial and neral decreased to a small extent through cultivation of the stored rhizome, whereas a large quantity of geraniol and geranyl acetate occurred in the newly propagated fresh rhizome.     

Studies on the Leaf Oils of Citrus Species

Leaf oil samples of four different citrus species were prepared from young leaves and the detailed composition of each leaf oil was investigated using gas chromatography, thin-layer chromatography and infrared spectrometry. The following components were identified: α-pinene, α-thujene, β-pinene, limonene, γ-terpinene, p-cymene, p-α-dimethylstyrene, β-humulene, β-selinene, trans-2-hexen-l-al, cis-3-hexen-l-ol, trans-2-hexen-l-ol, linalool terpinen-4-ol and α-terpineol. In addition, camphene, sabinene, β-myrcene, α-terpinene, β-elemene, caryophyllene, neral, geranial, nerol and geraniol were tentatively identified. Most of the components were found to be contained in common in the leaf oils of four different citrus species, but the relative contents of some of the components such as limonene, γ-terpinene, p-cymene, linalool, neral and geranial were distinctly different from species to species. Thus, gas chromatographic analyses of leaf oils seemed to be useful for the identification of citrus species.     

Chemical composition of essential oils of four Eucalyptus species and their phytotoxicity on silverleaf nightshade (Solanum elaeagnifolium Cav.) in Australia

Phytotoxicity and chemical composition of essential oils from four selected Eucalyptus species in Australia were investigated. Essential oils had stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.) when compared with a commercial eucalyptus oil and with 1,8-cineole. E. salubris oil had the highest inhibition index for silverleaf nightshade germination, root growth and shoot growth, while E. spathulata had the lowest inhibitory effect except root growth. Gas chromatography-mass spectrometry analysis revealed 56 compounds present in E. salubris oil, with 1,8-cineole (57.6?%), ??-pinene (10.9?%) and p-cymene (8.3?%) predominant. E. dundasii oil contained 55 identified compounds with 1,8-cineole (65.5?%) and ??-pinene (19.9?%) being the richest fractions. There were 56 compounds identified from E. brockwayii oil with ??-pinene (31.1?%), isopentyl isovalerate (20.2?%) and 1,8-cineole (16.9?%) as the most abundant components. E. spathulata oil contained 60 compounds, predominantly 1,8-cineole (52.9?%) and ??-pinene (31.0?%). Further study is required to determine the phytoxicity of the individual identified compounds on silverleaf nightshade and whether the observed phytotoxicity is attributable to a single compound or to the synergistic effects of several compounds.     

Variation in the leaf oil of Eucalyptus punctata

The steam-volatile leaf oil of Eucalyptus punctata. ssp. punctata has been shown to contain α-pinene, β-pinene, 1,8-cineole, p-cymene and cryptone. Several minor components have been tentatively identified by GLC. The wide variation in the leaf oil composition between individual trees indicated no grounds for the establishment of chemical varieties within the subspecies.     

The essential oil of ginger from Fiji

The essential oil of ginger (Zingiber officinale) from Fiji was analysed by GC-MS and a number of sesquiterpenes not reported previously in ginger oil were identified including α-copaene, β-bourbonene, α-bergamotene, α-selinene, calamenene and cuparene. The composition of the oil was unusual in having a much higher neral and geranial content than oils reported from India, Australia, Japan and Africa.     

Essential oil composition of four Lomatium Raf. species and their chemotaxonomy

The composition of the essential oils of Lomatium dasycarpum ssp. dasycarpum, Lomatium lucidum, Lomatium macrocarpum var. macrocarpum and Lomatium utriculatum is described. Identification of components was determined from their GC, GC/MS data and many were confirmed by coinjections with authentic samples. Several components were isolated by liquid and gas chromatographic techniques and their structures confirmed from their ¹H and ¹³C NMR spectral data. 2-Methyl and 3-methylbutanoates were the major components of L. dasycarpum fruits as well as stems and leaves oils. β-Phellandrene/limonene, decanal, dodecanal, bornyl acetate, germacrene D, α-humulene and bicyclogermacrene were the major components of the corresponding L. lucidum oils. α-Pinene and β-pinene were the major components of the fruit oil of L. macrocarpum. Its stem and leaf oil was rich in peucenin 7-methyl ether, β-caryophyllene, (Z)-3-hexenol, palmitic acid, linoleic acid and (E)-2-hexenal. Sabinene, (Z)-ligustilide, terpinen-4-ol, β-phellandrene/limonene, β-caryophyllene, myrcene, α-pinene and β-pinene were the major compounds in L. utriculatum fruit oil, while its stem and leaf oil was rich in (Z)-ligustilide, palmitic acid, terpinen-4-ol, linoleic acid and germacrene D. (Z)-Falcarinol was a major component of all the four root oils.     

Essential oil yield,composition, bioactivity and leaf morphology of Juniperus oxycedrus L. from Bulgaria and Serbia

Juniperus oxycedrus L. (Cupressaceae Bartlett) is widely distributed in countries with a Mediterranean climate. All plant parts contain highly aromatic essential oil (EO) and recently there have been efforts to introduce it as a cultivated crop. The species is known for its large morphological and chemical variation and its debatable taxonomic status. This study aimed to (1) compare content, composition, and antimicrobial activity of J. oxycedrus EO samples from plants growing in Bulgaria and Serbia, and (2) quantify morphological variations of leaves. Тhe EO content (yield) in dried juniper leaves varied from 0.06% (Кopaonik, Serbia) to 0.24% (Markovo, Bulgaria). We identified 51 EO constituents, belonging to monoterpenes, sesquiterpenes, and diterpenes. The class monoterpenes (monoterpene hydrocarbons and oxygenated monoterpenes) were the predominant compounds, representing 38.6–65.4% of the total EO, consisting primarily of α-pinene, limonene, sabinene, β-pinene, and β-myrcene. In addition, α-pinene was the major oil constituent in plants from all locations. Sesquiterpenes (sesquiterpene hydrocarbons and oxygenated sesquiterpenes) were the second largest class of constituents, which represented 19.3% tо 33.6% of the total EO. γ-Elemene was found only in the EO of J. oxycedrus from Bulgaria, while a high concentration of α-curcumene was found only in samples from Serbia (7.5–7.8%). Significant differences in antimicrobial activity of the EO were found in bacterial strains Bacillus cereus and Streptococcus pneumoniae. There was no significant difference among the mean leaf width of the six combinations location x sex, and the overall leaf mean width was 1.24 mm. However, there was a significant difference between the mean leaf lengths. In this study, none of the studied populations had a higher concentration of limonene than of α-pinene, indicating that the flora of the two countries include J. oxycedrus and not the previously reported J. deltoides. The results revealed significant variation in EO profile that may contribute to the development of new cultivars of J. oxycedrus.     

Constituents of the essential oil of a new chemotype of Elsholtzia strobilifera Benth.

The composition of the essential oil from a new chemotype of Elsholtzia strobilifera Benth. collected from sub-alpine region of central Himalaya, India, has been investigated by Gas Chromatography and Gas Chromatography–Mass Spectrometry. The GC of the oil revealed the presence of more than 50 constituents, of which neral (18.3%) and geranial (29.9%) were found to be the major compounds and an absence of monoterpene hydrocarbons. Acylfuran derivatives, the specific chemical markers of the essential oils from the genus Elsholtzia were not detected.     

Essential oil composition of juvenile leaves from coppiced Eucalyptus nitens

The essential oil of Eucalyptus nitens juvenile foliage harvested from coppiced trees contained α-pinene, limonene, 1,8-cineol, cis-ocimene and α-terpineol as principal components. Minor constituents were monoterpene alcohols, ketones, and aldehydes and 3-methylbutanal. Esters not previously identified in E. nitens leaf oil were ethyl 3-methylbutanoate, 3-methylbutyl-3-methylbutanoate, 3-methylbutyl hexanoate and hexyl 3-methylbutanoate.     

Composition of Aloysia gratissima leaf essential oil

Sabinene, β-pinene, copaenol and copaenone have been isolated and identified in A. gratissima leaf essential oil from plants growing in Uruguay.     

Volatile constituents in leaves of parsley

Volatile chemicals obtained from the leaves of parsley, Petroselinum sativum by steam distillation, isopentane extraction, and head-space analysis were identified by GLC-MS. The presence in leaf oil of α-pinene, β-pinene, myrcene, β-phellandrene, trans-β-ocimene, γ-terpinene, 1-methyl-4-isopropenyl benzene, and 1,3,8-p-menthatriene as shown by earlier investigators was confirmed. In the present studies, the number of volatile chemicals detected in the leaves was extended by an additional 42. Sniffing tests of effluent from a gas chromatograph of a concentrate from parsley leaves showed that 1,3,8-p-menthatriene was only one of several compounds that gave a parsley-like aroma.     

Composition and variability of essential oils of Platycladus orientalis growing in China

Essential oils were isolated from the leaves of Platycladus orientalis growing in 16 areas of China. The essential oils were analyzed by gas chromatography and gas chromatography-mass spectrometry. In total, 98 volatile compounds were identified. Chemical variability in essential oil composition was evaluated using cluster analysis and principal component analysis. The two analyses led to the identification of four chemotypes: α-pinene, α-pinene/3-carene, cedrol, and cedrol/terpinyl acetate. Geographically, the populations growing in close proximity had similar essential oil composition. The chemical variability could possibly be attributed to genetic and environmental factors.     

Chemical composition, antioxidant activity and inhibitory effects of essential oil of Eucalyptus teretecornis grown in north-western Himalaya against Alternaria alternata

The essential oil obtained from fresh leaves of Eucalyptus teretecornis (family Myrtaceae) was analysed by gas chromatography/mass spectrometry (GC/MS). Twenty eight compounds were identified and ??-pinene (22.55%), ??-pinene (22.50%), 1,8-cineole (19.84%), limonene (5.62%), ??-fenchol (3.10%), ??-phellandrene (2.90%), ??-eudesmol (2.66%) and 4-(2-methylcyclohex-1-enyl)-but-2-enal (2.34%) were the main components. The antifungal activity of the essential oil was assayed against Alternaria alternata using bioautography. Two main bioactive components namely a₁ (R _f ?=?0.27) and a₂ (R _f ?=?0.33) were observed that produced inhibition zone of 4?mm and 8?mm in diameter respectively. The minimum inhibitory amount (MIA) of a₁ and a₂ against A. alternata was determined as 28???g and 10???g, respectively using bioautography assay. Components corresponding to a₁ and a₂ were determined as ??-fenchol (oxygenated monoterpene) and ??-eudesmol (oxygenated sesquiterpene) respectively using GC/MS analysis. The antioxidant activity of the essential oil and its bioactive fraction was evaluated by DPPH radical scavenging assay, ??-carotene/linoleic acid bleaching assay, reducing power assay and metal chelating assay. In addition fraction of the essential oil that showed antioxidant activity was analyzed using GC/MS and ??-fenchol, 4-terpineol and carvacrol were the main components.     

Terpenoid chemosystematic studies of Abies grandis

Cortial essential oil from 395 typical Abies grandis and Abies grandis-Abies concolor intermediate trees collected in 48 locations was analyzed for composition of its monoterpenoids. The monoterpenoids were composed primarily of α-pinene, camphene, β-pinene, β-phellandrene and bornyl acetate, with tricyclene, 3-carene, myrcene and limonene in secondary quantities. Camphene, present in larger amounts in A. grandis and in smaller amounts in A. concolor var. lowiana, was used as a marker for studying intergradation of the two species in western and northwestern United States. A. grandis from northern Montana, Idaho and Washington, from British Columbia and Oregon and from Washington coastal areas could be classified as typical while the rest of the populations showed various degrees of intermediacy. The variability patterns agreed with the hypothesis that introgressive hybridization was the main reason for the intermediacy. Compared with morphological evaluations, the intermediate populations were chemically significantly more A. concolor-like. Typical A. grandis exhibited little population-to-population variability, in spite of its large geographic range. The results are correlated with and explained on the basis of existing paleobotanical records.     

Composition and antimicrobial activity of the essential oil of six Hypericum species from Serbia

The volatile composition of six Hypericum species has been studied. The essential oils were obtained by steam distillation in 500 mL H₂O for 2 h in a modified Clevenger apparatus with a water-cooled oil receiver to reduce hydrodistillation over-heating artifacts, and their analyses were performed by GC and GC–MS. Identification of the substances was made by comparison of mass spectra and retention indices with literature records. A total of 100 different compounds were identified. The main constituents of the investigated populations of each taxon have been revealed as follows: Hypericum alpinum: (−)-β-pinene, γ-terpinene, (−)-(E)-caryophyllene; Hypericum barbatum: (−)-α-pinene, (−)-β-pinene, (−)-limonene, (−)-(E)-caryophyllene, (−)-caryophyllene oxide; Hypericum rumeliacum: (−)-α-pinene, (−)-β-pinene, (−)-limonene, Hypericum hirsutum: nonane, undecane, (−)-(E)-caryophyllene, (−)-caryophyllene oxide; Hypericum maculatum: spathulenol, globulol; Hypericum perforatum: (−)-α-pinene, (Z)-β-farnesene, germacrene D; Monoterpene hydrocarbons were shown to be the main group of the taxa belonging to the section Drosocarpium, while the taxa of section Hypericum were more rich in sesquiterpene hydrocarbons.     

Influence of phosfon D and cycocel on growth and essential oil content of sage and peppermint

Foliar application of Phosfon D at 50–100 ppm stimulates the growth of Salvia officinalis (sage) and moderately retards the growth of Mentha piperita (peppermint), while increasing the essential oil yield of both species by 50–70 % Phosfon D increases the proportions of (−)-3-isothujone and (+)-3-thujone in sage oil and decreases the level of (−)-β-pinene and (+)-camphor, whereas this growth retardant increases the proportions of (+)-isomenthone and (+)-neoisomenthol in peppermint oil and decreases the level of(−)-menthone and (−)-menthoL Foliar application of Cycocel at 250–500 ppm slightly stimulates growth and essential oil formation in peppermint, and retards growth of sage with little effect on oil yield. The influence of Cycocel on sage oil composition was the opposite of that of Phosfon, with a tendency to increase the level of (−)-β-pinene and decrease the level of (−)-3-isothujone under severe stunting. The effect of Cycocel on the composition of peppermint varied with concentration. The influence of growth retardants on essential oil composition and yield are most readily explained by alterations in the levels or activities of the relevant enzymes.     

Molecular and chemical characterization of the most widespread Ocimum species

DNA fingerprinting (AFLP) and chemical analyses of essential oils were utilized to define the extent of variation existing in the genus Ocimum. Research was carried out on 22 Ocimum accessions representing seven species. Concerning the essential oil composition of all investigated accessions, 115 compounds were identified. UPGMA cluster analysis, based on Euclidian distances of essential oil constituents between all pairs of accessions, showed four well-supported clusters (O. tenuiflorum, O. basilicum/O. africanum, O. basilicum, and O. americanum/O. africanum). Relating to the essential oil composition of all of the investigated accessions, 17 compounds were identified as the main ones, and according to them 13 chemotypes were determined. AFLP relationships were determined by neighbor-joining (NJ) cluster analysis based on Dice??s distance matrix and by maximum parsimony (MP) analysis. O. basilicum, O. americanum/O. africanum, O. tenuiflorum, and O. gratissimum represented four clusters supported with high bootstrap values. A neighbor-net diagram allowed the visualization of apparently conflicting data by revealing relationships between genotypes and chemotypes. Concerning the O. africanum species, two distinct chemotypes, geranial/neral (accession 11) and estragol (accession 10), have been established, while all the studied O. americanum accessions belong to the geranial/neral chemotype. This could be additional evidence that O. americanum is one of the parents of O. africanum. Furthermore, the fact that the O. africanum accession (10) as well as O. basilicum ??Purpurascens?? and O. basilicum ??Erevanskii?? accessions belong to the estragol chemotype supports the theory that O. africanum is one of the parents of these two O. basilicum accessions.     

Antioxidative, anticancer and genotoxic properties of α-pinene on N2a neuroblastoma cells

α-Pinene, an organic monoterpene, is found in essential oils of pine and coniferous trees. To date, although various biological activities of α-pinene have been demonstrated, its neurotoxicity has never been explored. Therefore in this study, we aimed to describe in vitro antiproliferative and/or cytotoxic properties by 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test, genotoxic damage potentials by single cell gel electrophoresis, and oxidative effects by total antioxidant capacity (TAC) and total oxidative stress (TOS) analysis of α-pinene. Statistical analysis of MTT assay results indicated significant (p < 0.05) decreases of the cell proliferation rates in healthy neurons treated with α-pinene at only 400 mg/L, while significant decreases were observed in N2a cells at 100, 200 and 400 mg/L. On the other hand, the mean values of the total scores of cells showing DNA damage were not found significantly different from the control values on both cells. In addition, our results indicated that 10 and 25 mg/L of α-pinene treatment caused increases of TAC levels in primary rat neurons without any alterations of its level in N2a cells. However, α-pinene treatments at higher doses led to increases of TOS levels in both cell types. Overall our results suggest that α-pinene is of a limited therapeutic use as an anticancer agent.