Citronellyl Acetate Research Articles

Chemical composition of the leaf essential oil of Antidesma venosum E. Mey. ex. Tul. and comparative phytochemical and pharmacognostic analysis of its leaf, stem bark and root

The leaf of the ethnomedicinally important plant, Antidesma venosum , was hydro-distilled to get the essential oil using a Clevenger-type apparatus. The oil was analyzed on Shimadzu QP2010 SE GC-MS to establish the chemical composition. The leaf, stem and bark of root of the plant were extracted and subjected to phytochemical and pharmacognostic analysis to establish their profiles and similarities, using standard methods. The results of the essential oils analysis revealed that the major components included (R)-(+)-Citronellal (28.97%), citronellyl acetate (11.98%), caryophyllene (7.14%), tetradecanal (6.97%), tetracosane (5.96%), caryophyllene oxide (4.65%) and phytol (4.11%). The results of phytochemical screening showed that the stem bark contain saponin, carbohydrate, alkaloid, steroid, tannin and flavonoid while reducing sugar and anthraquinones were absent. The root showed the presence of flavonoids, steroid and saponins, while alkaloids, reducing sugar carbohydrate and anthraquinones were absent. Saponins, carbohydrate, alkaloids, reducing sugars tannins and flavonoid were found in the leaf, while steroid and anthraquinones were absent. The pharmacognostics profile of the leaf revealed that moisture content was 14%, total ash value (8.5%), total solid (86%), water extractive value (4.97%) and alcohol extractive value (19.6%). For the stem bark, the moisture content was 12.1%, ash value (6.6%), total solid (87.9%), water extractive value (4.34%) and alcohol extractive value (8.33%) and for the root moisture content was 13.1%, ash value (8.6%), total solid (86.9%), water extractive value (16%) and alcohol extractive value (45.1%). The phyto-anatomical character (epidermal peeling) carried out on the leaf revealed the presence of parasitic stomata, unicellular trichomes and polygonal cell shape at the lower surface and while stomata and trichomes were absent on the upper surface. The findings of this study establish the bases for its ethnopharmacological applications, and provide information that could be used to determine sample authenticity.

De novo production of six key grape aroma monoterpenes by a geraniol synthase-engineered S. cerevisiae wine strain.

BackgroundMonoterpenes are important contributors to grape and wine aroma. Moreover, certain monoterpenes have been shown to display health benefits with antimicrobial, anti-inflammatory, anticancer or hypotensive properties amongst others. The aim of this study was to construct self-aromatizing wine yeasts to overproduce de novo these plant metabolites in wines.ResultsExpression of the Ocimum basilicum (sweet basil) geraniol synthase (GES) gene in a Saccharomyces cerevisiae wine strain substantially changed the terpene profile of wine produced from a non-aromatic grape variety. Under microvinification conditions, and without compromising other fermentative traits, the recombinant yeast excreted geraniol de novo at an amount (~750 μg/L) well exceeding (>10-fold) its threshold for olfactory perception and also exceeding the quantities present in wines obtained from highly aromatic Muscat grapes. Interestingly, geraniol was further metabolized by yeast enzymes to additional monoterpenes and esters: citronellol, linalool, nerol, citronellyl acetate and geranyl acetate, resulting in a total monoterpene concentration (~1,558 μg/L) 230-fold greater than that of the control. We also found that monoterpene profiles of wines derived from mixed fermentations were found to be determined by the composition of the initial yeast inocula suggesting the feasibility of producing ‘à la carte’ wines having predetermined monoterpene contents.ConclusionsGeraniol synthase-engineered yeasts demonstrate potential in the development of monoterpene enhanced wines.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-015-0306-5) contains supplementary material, which is available to authorized users.

Comparative Chemoprofiling and Biological Potential of Three Eucalyptus Species Growing in Jammu and Kashmir

:Chemical profile of the essential oils of three Eucalyptus species viz. Eucalyptus citriodora, Eucalyptus lanceolatus and Eucalyptus globulus was determined by GC-MS. Seventeen components were identified in E. globulus oil, among them p-cymene (31.88 %), eucalyptol (17.47 %), α-pinene (17.18 %), were the major components. Major components of E. lanceolatus oil were p-cymene (54.75 %), eucalyptol (18.88 %) and β-phellandrene (18.86 %) and four major monoterpenes compounds viz., Isopulegol (51.12 %), β-citronellal (29.15 %), L-isopulegol (11.49 %) and citronellyl acetate (5.77 %) were identified in E. citriodora oil. Antimicrobial activities of the essential oils were evaluated against seven bacterial and three plant pathogenic fungal strains.E. citriodora oil inhibited the growth of all the test bacterial strains with the significant inhibition against Pseudomonas alcaligenes (23±0.73 mm) and also showed potential antifungal activity especially against Alternaria alternata (IC value 0.16±0.012 %). E. lanceolatus essential oil showed strong antibacterial activity against Micrococcus luteus (33±0.97 mm) and Bacillus subtilis (27±0.69 mm) and also possesses moderate antioxidant activity (IC value 534±9.31 µg/ml) in DPPH system. E. citriodora and E. globulus showed negligibleradical scavenging activity. Cytotoxic potential of the E. citriodora oil was found maximum against breast (T 47D) and prostrate (PC-3) cancer cell lines with 86 % and 76 % growth inhibitions, respectively. The present study emphasizes that E. citriodora essential oil is a potential inhibitor of different bacterial and fungal strains and also possesses significant cytotoxic activity against human cancer cell lines, whereas of E. lanceolatus essential oil is a noteworthy free radical scavenger.

Application of lipase immobilized on the biocompatible ternary blend polymer matrix for synthesis of citronellyl acetate in non-aqueous media: Kinetic modelling study

This work reports the use of new support for immobilization of lipase Burkholderia cepacia (BCL) matrix made up of polylactic acid (PLA), chitosan (CH), and polyvinyl alcohol (PVA). Initially lipase from various microbial sources and immobilization support composition was screened to obtain a robust biocatalyst. Among various biocatalysts preparation, the PLA:PVA:CH:BCL (1:6:1:2) was worked as a robust biocatalyst for the citronellyl acetate synthesis. Various reaction parameters were studied in detail to obtain the suitable reaction conditions for model citronellyl acetate synthesis reaction. Various kinetic parameters such as rmax, Ki(citronellol), Km(citronellol), Km(vinyl acetate) were determined using non-linear regression analysis for the ternary complex as well as bi–bi ping-pong mechanism. The experimental results and kinetic study showed that citronellyl acetate synthesis catalyzed by immobilized lipase BCL followed the ternary complex mechanism with inhibition by alcohol (citronellol). The energy of activation for citronellyl acetate synthesis was found to be lower for immobilized lipase (8.9kcal/mol) than aggregated lipase (14.8kcal/mol) enzyme. The developed biocatalyst showed four to fivefold higher catalytic activity and excellent recyclability (up to six cycles) than the aggregated lipase.

Essential Oil Yield of Corymbia citriodora as Influenced by Harvesting Age, Seasonal Variation and Provenance at Citrifine Plantations in Northern Malawi

Essential Oil Yield of Corymbia citriodora as Influenced by Harvesting Age, Seasonal Variation and Provenance at Citrifine Plantations in Northern Malawi Corymbia citriodora grown in Citrifine Plantations in Chikangawa, Northern Malawi was evaluated for essential oil yield as influenced by harvesting age, season variation and provenance at the plant age of the three and four years. All the parameters harvesting age, season variation and provenance significantly affected essential oil yield of Corymbia citriodora leaves. Citronellal was the major compound (˃80%) in the oil followed by citronellol (5.3 to 7.7%), linalool (2.1 to 2.2%), isopulegol (1.2 to 2.1%) and citronellyl acetate (0.6 to 0.8%). Essential oil yield decreased with increasing plant age. Cold-wet season (May to August) particularly in the month of August produced significantly (P<0.001) higher essential oil yield than warm-wet and dry seasons at both harvesting age of three and four years. The differences in essential oil yield due to season can be attributed to changes in temperature and humidity, also to different stage metabolism.

Flowery odor formation revealed by differential expression of monoterpene biosynthetic genes and monoterpene accumulation in rose (Rosa rugosa Thunb.)

Rosa rugosa is an important ornamental and economical plant. In this paper, four genes encoding 1-deoxy-d-xylulose-5-phosphate synthase (DXS), 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), alcohol acyltransferase (AAT) and linalool synthase (LIS) involved in the monoterpene biosynthesis pathways were isolated from R. rugosa ‘Tangzi’, and the expression patterns of these genes in different flower development stages and different parts of floral organs were determined by real-time quantitative fluorescence PCR. Furthermore, a comprehensive analysis was carried out into the relationship between expression of four monoterpene synthesis genes and accumulation of main volatile monoterpenes and their acetic acid ester derivatives. The results showed that the genes RrDXS, RrDXR and RrLIS showed consistent expressions during the development process for R. rugosa flower from budding to withering stage, the overall expression levels of gene RrDXS and RrLIS were obviously lower as compared with those of gene RrDXR and RrAAT. Although the gene RrDXS, RrDXR, RrAAT and RrLIS were expressed in all parts of R. rugosa floral organs, the expression levels varied significantly. The variations in the constituent and content of volatile monoterpenes including citronellol, geraniol, nerol, linalool, citronellyl acetate, geranyl acetate and neryl acetate at different development stages and parts of floral organs were significantly different. On this basis, we concluded that the gene RrDXR and RrAAT might play a key role in the biosynthesis of volatile monoterpenes in R. rugosa flowers, and the two genes are important candidate genes for the regulation of secondary metabolism for rose aromatic components.

Bioefficacy of acyclic monoterpenes and their saturated derivatives against the West Nile vector Culex pipiens

Twenty acyclic monoterpenes with different functional groups (acetoxy, hydroxyl, carbonyl and carboxyl) bearing a variable number of carbon double bonds were assayed as repellent and larvicidal agents against the West Nile vector Culex pipiens. Seven of them were derivatives that were synthesized through either hydrogenation or oxidation procedures. All repellent compounds were tested at the dose of 1mgcm−2 and only neral and geranial were also tested at a 4-fold lower dose (0.25mgcm−2). Repellency results revealed that geranial, neral, nerol, citronellol, geranyl acetate and three more derivatives dihydrolinalool (3), dihydrocitronellol (5) and dihydrocitronellyl acetate (6) resulted in no landings. Based on the LC50 values the derivative dihydrocitronellyl acetate (6) was the most active of all, resulting in an LC50 value of 17.9mgL−1. Linalyl acetate, citronellyl acetate, neryl acetate, geranyl acetate, dihydrocitronellol (5), dihydrocitronellal (7), citronellol, dihydrolinalyl acetate (2), citronellic acid and tetrahydrolinalyl acetate (1) were also toxic with LC50 values ranging from 23 to 45mgL−1. Factors modulating toxicity have been identified, thus providing information on structural requirements for the selected acyclic monoterpenes. The acetoxy group enhanced toxicity, without being significantly affected by the unsaturation degree. Within esters, reduction of the vinyl group appears to decrease potency. Presence of a hydroxyl or carbonyl group resulted in increased activity but only in correlation to saturation degree. Branched alcohols proved ineffective compared to the corresponding linear isomers. Finally, as it concerns acids, data do not allow generalizations or correlations to be made.

TRP and ASIC channels mediate the antinociceptive effect of citronellyl acetate

BackgroundCitronellyl acetate (CAT), a monoterpene product of the secondary metabolism of plants, has been shown in the literature to possess several different biological activities. However, no antinociceptive abilities have yet been discussed. Here, we used acute pain animal models to describe the antinociceptive action of CAT.MethodsThe acetic acid-induced writhing test and the paw-licking test, in which paw licking was induced by glutamate and formalin, were performed to evaluate the antinociceptive action of CAT and to determine the involvement of PKC, PKA, TRPV1, TRPA1, TRPM8 and ASIC in its antinociceptive mechanism. To do so, we induced paw-linking using agonists.ResultsCAT was administered intragastrically (25, 50, 75, 100 and 200mg/kg), and the two higher doses caused antinociceptive effects in the acetic acid model; the highest dose reduced pain for 4h after it was administered (200mg/kg). In the formalin test, two doses of CAT promoted antinociception in both the early and later phases of the test. The glutamate test showed that its receptors are involved in the antinociceptive mechanism of CAT. Pretreatment with CAT did not alter locomotor activity or motor coordination. In an investigation into the participation of TRP channels and ASICs in CAT’s antinociceptive mechanism, we used capsaicin (2.2μg/paw), cinnamaldehyde (10mmol/paw), menthol (1.2mmol/paw) and acidified saline (2% acetic acid, pH 1.98). The results showed that TRPV1, TRPM8 and ASIC, but not TRPA1, are involved in the antinociceptive mechanism. Finally, the involvement of PKC and PKA was also studied, and we showed that both play a role in the antinociceptive mechanism of CAT.ConclusionThe results of this work contribute information regarding the antinociceptive properties of CAT on acute pain and show that, at least in part, TRPV1, TRPM8, ASIC, glutamate receptors, PKC and PKA participate in CAT’s antinociceptive mechanism.

A New Source of Elemol Rich Essential Oil and Existence of Multicellular Oil Glands in Leaves of the Dioscorea Species

Dioscorea species is a very important food and drug plant. The tubers of the plant are extensively used in food and drug purposes owing to the presence of steroidal constituent's diosgenin in the tubers. In the present study, we report for the first time that the leaves of Dioscorea composita and Dioscorea floribunda grown under the field conditions exhibited the presence of multicellular oil glands on the epidermal layers of the plants using stereomicroscopy (SM) and scanning electron microscopy (SEM). Essential oil was also isolated from the otherwise not useful herbage of the plant, and gas chromatographic-mass spectroscopy analysis revealed confirmation of the essential oil constituents. Out of the 76 compounds detected in D. floribunda and 37 from D. composita essential oil, major terpenoids which are detected and reported for Dioscorea leaf essential oil are α-terpinene, nerolidol, citronellyl acetate, farnesol, elemol, α-farnesene, valerenyl acetate, and so forth. Elemol was detected as the major constituent of both the Dioscorea species occupying 41% and 22% of D. Floribunda and D. composita essential oils, respectively. In this paper, we report for the first time Dioscorea as a possible novel bioresource for the essential oil besides its well-known importance for yielding diosgenin.

Lipase-catalyzed transesterification synthesis of citronellyl acetate in a solvent-free system and its reaction kinetics

The lipase-catalyzed citronellol synthesis of citronellyl acetate via transesterification was investigated in a solvent-free system. After screening several lipases, the lipase from Pseudomonas fluorescens was identified as the optimal enzyme for the system. The optimal reaction temperature was 40 °C. The external diffusion limitation could be greatly reduced by increasing the agitation speed to 200 rpm. A linear relationship between the initial reaction rate and an enzyme load of up to 6 mg mL−1 demonstrated that the internal diffusion limitations could be minimized. Substrate inhibition was absent when the substrate concentration was below 500 mmol L−1, but the experimental results indicated that the product inhibition effect should be considered. The results from the reaction kinetics analysis showed that the reaction obeys the ping-pong bi–bi mechanism that is inhibited by citronellyl acetate. Matlab was used to simulate the model parameters. The experimental values could be satisfactorily fitted to the simulated values with a relative error of 11.98 %.

Toxicity ofZanthoxylum piperitumandZanthoxylum armatumOil Constituents and Related Compounds toStomoxys calcitrans(Diptera: Muscidae)

Zanthoxylum plants (Rutaceae) have drawn attention because they contain insecticidal principles against insects. An assessment was made of the insecticidal and acetylcholinesterase (AChE) inhibitory activities of Zanthoxylum piperitum steam distillate and Zanthoxylum armatum seed oil, their 28 constituents, and eight structurally related compounds against female stable fly, Stomoxys calcitrans (L.). Results were compared with those of two organophosphorus insecticides chlorpyrifos and dichlorvos. Potent fumigant toxicity was observed with cuminaldehyde, thymol, (1S)-(-)-verbenone, (-)-myrtenal, carvacrol, (S)-(Z)-verbenol, Zanthoxylum piperitum steam distillate, cuminyl alcohol, Zanthoxylum armatum seed oil, piperitone, (-)-(Z)-myrtanol, and citronellal (LC50, 0.075-0.456 microg/cm3). However, they were five orders of magnitude less toxic than either chlorpyrifos or dichlorvos. An in vitro bioassay using female fly heads indicates that strong AChE inhibition was produced by citronellyl acetate, alpha-pinene, thymol, carvacrol, and alpha-terpineol (1.20-2.73 mM), but no direct correlation between fly toxicity and AChE inhibition by the test compounds was observed. Structure-activity relationships indicate that structural characteristics, such as carbon skeleton, degrees of saturation and types of functional groups, and vapor pressure parameter, appear to play a role in determining toxicities of the test monoterpenoids to stable flies. Global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment justify further studies on Z. piperitum and Z. armatum oil-derived materials as potential insecticides for the control of stable fly populations.

Key Olfactory Cues for Beer Oxidation

Numerous compounds that are subject to concentration change have been suggested as markers of beer flavor instability. In the current work, GCxGC-MS-olfactometry was used to identify significant changes in aroma compound levels as beer aged. The key was to search for the significant changes in aroma, not necessarily the most intense aromas. The compounds that significantly increased or decreased in aroma during 12 weeks 85°F (29.4°C) forced aging of an American lager were methanethiol, methional, dimethyl trisulfide, phenylacetaldehyde, 1,1,6-trimethyl-1,2,3,4-tetrahydronapthalene (TTN), citronellyl acetate, and delta-cadinene. TTN is a flavor-active norisoprenoid degradation product of carotenoids. This is an example of the degradation product of an antioxidant contributing to oxidation character. Delta-cadinene is a hop oil sesquiterpene. During beer fermentation, yeast biotransformation of the hop-derived monoterpene alcohol geraniol leads to beta-citronellol, which in turn is esterified to citronellyl acetate. The validity of the importance of this group of compounds as key olfactory cues for beer oxidation was demonstrated by the excellent partial least squares multivariate analysis correlation (R2 = 0.99) between the sensory panel scores (for oxidation increases over 12 weeks) and the flavor stability compound level changes (MS-selected ion monitoring values).

Effect of season on yield and composition of the essential oil of Eucalyptus citriodora Hook. leaf grown in sub-tropical conditions of North India

Seasonal variation of the essential oil of Eucalyptus citriodora leaves were analysed by Gas chromatography mass spectrometry (GC-MS) analysis in the trees grown at subtropical conditions of North Indian plains for commercial cultivation and determination of proper harvesting time. At this condition, oil yield ranged between 1.0 to 2.1% during different months. Oil yield was observed to be high during April to September, when temperature was high and the yield was low during November to March, when the temperature was relatively low. However, during rainy season, when both temperature and humidity was high, oil yield was also observed to be quite high (1.8 to 2.1%). At this condition, the major constituent of oil was citronellal (69.7 to 87.4%) followed by citronellol (5.1 to 9.9%), linalool (2.1 to 6.4%), isopulegol (0.9 to 3.1%) and citronellyl acetate (0.4 to 1.2). Concentration of citronellal decreased during the summer and rainy seasons, while concentration of rest of the major constituents increased during this period. Yield of oil and concentrations of citronellal was observed to be comparable to the plants grown commercially in South India but concentration of rest of the constituents decreased considerably. Key words: Eucalyptus citriodora, seasonal variation, essential oil composition, citronellal, citronellyl acetate, linalool, citronellol.

Characterization and biological activity of essential oils from fruits of Zanthoxylum xanthoxyloides Lam. and Z. leprieurii Guill. &amp; Perr., two culinary plants from Cameroon

ABSTRACTEssential oils obtained by hydrodistillation of dried fruits of Zanthoxylum xanthoxyloides and Z. leprieurii (Rutaceae), were analysed by gas chromagraphy–flame ionization detection and gas chromatography–mass spectrometry. In the former, the major volatiles resulted citronellol (29.9%) and geraniol (11.5%), followed by citronellyl acetate (5.5%), limonene (5.5%) and citronellal (4.6%), while in the latter the major compounds were (E)‐β‐ocimene (29.4%), myrcene (28.6%), limonene (13.6%) and α‐pinene (8.1%), respectively. The chemical composition supports the traditional use of these plants as spices in local food. The oils were also tested for antiproliferative, antimicrobial and antioxidant activities by MTT assay, agar disc diffusion method, and DPPH, ABTS and β‐carotene–linoleic acid assay, respectively. The noteworthy cytotoxic effects of Z. xanthoxyloides are probably related to the presence of geraniol and citronellol, which exhibited strong antiproliferative activity against all the tested human tumor cell lines, and support the local traditional use of this plant for the treatment of various cancers. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Immunotoxicity activity from the essential oils of coriander (Coriandrum sativum) seeds

The seeds of the Coriandrum sativum were extracted and the essential oil composition and immunotoxicity effects were studied. The analysis of the essential oil was conducted by gas chromatography–mass spectroscopy, which revealed 33 components, representing 99.99% of the total oil from the seeds of coriander. The major components are linalool (55.09%), α-pinene (7.49%), 2,6-Octadien-1-ol, 3,7-dimethyl-, acetate, (E)- (5.70%), geraniol (4.83%), 3-Cyclohexene-1-methanol, α,α,4-trimethyl- (4.72%), hexadecanoic acid (2.65%), tetradecanoic acid (2.49%), 2-α-pinene (2.39%), citronellyl acetate (1.77%), and undecanal (1.29%). The seed oil had significant toxic effects against the larvae of Aedes aegypti with an LC50 value of 21.55 ppm and LC90 value of 38.79 ppm. The above data indicate that the major components in the essential oil of coriander play an important role as immunotoxicity on the A. aegypti.

A clean enzymatic process for producing flavour esters by direct esterification in switchable ionic liquid/solid phases

A clean biocatalytic approach for producing flavour esters using switchable ionic liquid/solid phases as reaction/separation media has been developed. The phase behaviour of different IL/flavour acetyl ester (geranyl acetate, citronellyl acetate, neryl acetate and isoamyl acetate) mixtures was studied at several concentrations, resulting for all cases in fully homogeneous liquid media at 50 °C, and solid systems at room temperature. By using an iterative centrifugation protocol on the solid IL/flavour ester mixtures at controlled temperatures, the solid IL phase and the liquid flavour ester phase can be easily separated. The excellent suitability of an immobilized Candida antarctica lipase B (Novozym 435) catalyst in the esterification reaction between an aliphatic carboxylic acid (acetic, propionic, butyric or valeric) and a flavour alcohol (isoamyl alcohol, nerol, citronellol or geraniol) in N,N′,N′′,N′′′-hexadecyltrimethyl-ammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2])IL has been demonstrated, the product yield being improved up to 100% under appropriate reaction conditions (enzyme amount, dehydrating molecular sieves, etc.) at 50 °C. The enzymatic synthesis of sixteen different flavour esters was carried out in [C16tma][NTf2] by means of this approach, providing products of up to 0.757 g mL−1 concentration after IL separation. The residual activity of the enzyme/IL system during seven consecutive operation cycles was shown to be practically unchanged after reuse.

Chemical composition of the essential oils of Nepeta laevigata and Nepeta elliptica from India

The genus Nepeta (Lamiaceae), also called Glechoma and Cataria, is a multiregional genus and consists of about 250 species of perennial herbs distributed in central and southern parts of Europe, Asia, and the Middle East [1–3]. These plants are commonly known as catmint [4], and about 30 species occur in India. Many Nepeta species have been reported to be biologically active and are used in folk medicine because of their spasmodic, diuretic, antiseptic, antitussive, antiasthmatic, and febrifuge activities [5–9]. Several Nepeta species are also reported to reduce serum lipids and to possess anti-inflammatory effects [10, 11]. Most Nepeta species are rich in essential oils, and various biologically active iridoids/monoterpene nepetalactones have been reported in several Nepeta species possessing diverse biological activities, viz., feline attractant, canine attractant, insect repellant, arthropod defense [12, 13], antibacterial, antifungal, and antiviral activities [14]. N. laevigata and N. elliptica are distributed through Afghanistan, China, Nepal, Pakistan, and India. In India, the two plant species are largely confined to Himachal Pradesh, Jammu and Kashmir, and Uttar Pradesh. Nepeta laevigata, also known as Betonica laevigata, is a perennial aromatic herb that grows to a height of 80 cm, is white pubescent, and has petiole 2–12 mm and leaf blade ovate to triangular, while N. elliptica is a small ascending or flexuous herb, 30–60 cm high. Both N. laevigata and N. elliptica are used in traditional medicine. Nepeta laevigata, is reported to be used locally in fevers and for sore throat, while, as an infusion of the seeds, N. elliptica is used in dysentery. According to our finding, there is no report on the chemical compostion of the essential oil of N. laevigata and N. elliptica growing in J & K, India, so the aim of the present work was to compare the chemical composition of these two Nepeta species. The chemical constituents of the volatile oils were analyzed by capillary GC-FID and GC-MS. The components of the oils of the air-dried aerial parts of N. laevigata and N. elliptica are listed in Table 1 with their percentages and relative retention indices (RRI). The different chemical constituents of the essential oils are listed in order of their elution from an RTX-5 column. As shown, 24 components belonging to different class of compounds were identified in the oil of N. laevigata, making up 86.7% of the total oil. -Citronellol (16.5%), germacrene D (19.4%), -caryophyllene (10.8%), -bisabolol oxide B (12.4%), -bourbonene (4.5%), -humulene (3.5%), spathulenol (3.9%), and -bisabolol (5.3%) were the major ones. Other constituents such as 4a,7,7a-nepetalactone (2.0%), allo-aromadendrene (1.1%), and caryophyllene oxide (3.2%) were present in small amounts. In addition, some other constituents such as -pinene, 1,8-cineole, linalool, geraniol, citronellyl acetate, etc. were present in trace amounts. The essential oil composition is dominated by the presence of sesquiterpene hydrocarbons, oxygenated sesquiterpenes, and oxygenated monoterpenes constituting 40.9%, 25.1%, and 20.7%, respectively, of the total oil composition. Of the various nepetalactone isomers, viz., 4a,7,7a-nepetalactone, 4a,7,7a-nepetalactone, and 4a,7,7a-nepetalactone, which have been labeled as the biochemical markers of the Nepeta essential oils and are very useful in chemotaxonomic studies, only one nepetalactone isomer viz., 4a, 7, 7a-nepetalactone, as a minor constituent, was present in the essential oil of Nepeta laevigata. -Caryophyllene, which is one of the major constituents of the essential oil, has been reported in some Nepeta species such as N. depauperata [15], N. flavida [16], and N. nuda [17] as the major component. Likewise, germacrene-D, the other major constituent of the oil sample, has also been reported in various other Nepeta species such as Nepeta macrosiphon [18] and Nepeta sintensii [19]. In addition, the other major components such as -bourbonene and spathulenol have been reported in N.depauperata [15], N. macrosiphon [18], and N. sintensii [19].

Fumigant toxicity of lemon eucalyptus oil constituents to acaricide‐susceptible and acaricide‐resistant Tetranychus urticae

This study was aimed at assessing the fumigant toxicity of 14 essential oil constituents from lemon eucalyptus, Eucalyptus citriodora Hook, and another ten known compounds to females of acaricide-susceptible, chlorfenapyr-resistant, fenpropathrin-resistant, pyridaben-resistant and abamectin-resistant strains of Tetranychus urticae Koch. Menthol (LC(50) , 12.9 µg cm(-3) ) was the most toxic compound, followed by citronellyl acetate (16.8 µg cm(-3) ), against the susceptible females. High toxicity was also produced by β-citronellol, citral, geranyl acetate and eugenol (LC(50) , 21.7-24.6 µg cm(-3) ). The fumigant toxicity of these compounds was almost identical against females from either of the susceptible and resistant strains, indicating that the compounds and acaricides do not share a common mode of action or elicit cross-resistance. Global efforts to reduce the level of highly toxic synthetic acaricides in the agricultural environment justify further studies on materials derived from lemon eucalyptus oil, particularly menthol and citronellyl acetate, as potential acaricides for the control of acaricide-resistant T. urticae as fumigants with contact action.

Volatile constituents of Zosimia radians Boiss. and Hohen from Iran

The essential oil of the aerial parts of Zosimia radians Boiss. & Hohen belonging to the Apiaceae family was obtained by hydrodistillation and analysed by GC and GC–MS. Thirty-nine compounds representing 95.7% of the oil were identified. Among them, citronellyl acetate (16.3%) and octyl butyrate (15.0%) were the most abundant.

Anointing Chemicals and Hematophagous Arthropods: Responses by Ticks and Mosquitoes to Citrus (Rutaceae) Peel Exudates and Monoterpene Components

Some birds and mammals roll on or wipe themselves with the fruits or leaves of Citrus spp. or other Rutaceae. These anointing behaviors, as with anointing in general, are thought to function in the topical acquisition of chemicals that deter consumers, including hematophagous arthropods. We measured avoidance and other responses by nymphal lone star ticks (Amblyomma americanum) and adult female yellow fever mosquitoes (Aedes aegypti) to lemon peel exudate and to 24 volatile monoterpenes (racemates and isomers), including hydrocarbons, alcohols, aldehydes, acetates, ketones, and oxides, present in citrus fruits and leaves in order to examine their potential as arthropod deterrents. Ticks allowed to crawl up vertically suspended paper strips onto a chemically treated zone avoided the peel exudate and geraniol, citronellol, citral, carveol, geranyl acetate, α-terpineol, citronellyl acetate, and carvone. Ticks confined in chemically treated paper packets subsequently were impaired in climbing and other behaviors following exposure to the peel exudate and, of the compounds tested, most impaired to carveol. Mosquitoes confined in chambers with chemically treated feeding membranes landed and fed less, and flew more, when exposed to the peel exudate than to controls, and when exposed to aldehydes, oxides, or alcohols versus most hydrocarbons or controls. However, attraction by mosquitoes in an olfactometer was not inhibited by either lemon peel exudate or most of the compounds we tested. Our results support the notion that anointing by vertebrates with citrus-derived chemicals deters ticks. We suggest that some topically applied compounds are converted into more potent arthropod deterrents when oxidized on the integument of anointed animals.