Monoterpenes Research Articles

PRESENCE OF LEUCOPLASTS IN SECRETORY CELLS AND OF MONOTERPENES IN THE ESSENTIAL OIL: A CORRELATIVE STUDY

ABSTRACT Analytical and structural studies were performed on 45 species of higher plants containing specialized secretory structures and/or producing essential oils or resins. Significant amounts of volatile compounds, mainly monoterpenes and sesquiterpenes, were recovered from these species. The specialized structures included glandular hairs, resin ducts, secretory cavities and idioblasts. During the ultrastructural investigation, special attention was paid to the plastidome. A number of secretory cells contain true leucoplasts, devoid of thylakoids and ribosomes. The comparison between analytical and structural data showed a very close correlation between the presence of leucoplasts in secretory cells and the significant quantities of monoterpenes (hydrocarbons or oxygenated compounds) in the volatile extract. Moreover, a morphometric estimation of leucoplast development in the cells suggested a quantitative relationship between the expansion of this plastidome and the ratio of monoterpenes in the oil....

Supercritical carbon dioxide fractionation of T. minuta and S. officinalis essential oils: Experiments and process analysis

Essential oils are an important source of compounds with different degree of biocidal activity against microorganisms, insects, weeds and other pathogens. They have potential application in pharmaceutical, cosmetic and food industry, as well as for agriculture and crop protection. Supercritical fluid fractionation is an interesting technology for the selective removal of monoterpenes (MT) and the purification or enrichment of the more bioactive oxygenated terpenes (OT), resulting in more effective, stable and water soluble products. In this work, the fractionation of Tagetes minuta and Salvia officinalis essential oils with carbon dioxide is experimentally studied in a semicontinuous apparatus at 313K and 80bar. Successive extracts are collected and the composition determined by gas chromatography. Process behavior is modeled with the group contribution equation of state (GC-EOS), showing a good agreement between model predictions and experimental results. The GC-EOS model is applied to the simulation and analysis of two continuous fractionation schemes: a simple countercurrent column and a countercurrent column with external reflux. The influence of operation variables (temperature, pressure, solvent-to-feed ratio, thermal gradient, reflux ratio) is studied in order to maximize OT concentration and recovery in the raffinate and to minimize carbon dioxide consumption. Experimental and simulation results are discussed in terms of the relative volatilities between MT and OT fractions. Particularly in the case of S. officinalis, the presence of several OT of intermediate volatility and a significant amount of higher molecular weight sesquiterpenes (ST) limits the separation performance, even when external reflux is applied.

Variability in essential oil composition of sage (Salvia officinalis L.) grown under North Western Himalayan Region of India

Common sage (Salvia officinalis L.; Lamiaceae) is one of the most important herb known for its essential oil richness and extensive use in folk medicine. The essential oil from aerial parts of S. officinalis L. collections grown under temperate climate of Uttarakhand, India, was analyzed by gas chromatography and gas chromatography mass spectroscopy (GC/MS). The essential oil content of S. officinalis was found to vary between 1.11 to 2.76% on dry weight basis. A total of 35 compounds were identified, representing 94.21 to 99.36% of the total oils. The range of major constituents present among six sage collections were: α-thujone (21.43 to 40.10%), β-thujone (2.06 to 7.41%), camphor (11.31 to 37.67%), 1,8-cineole (4.47 to 9.17%), α-humulene (4.58 to 9.51%), camphene (1.89 to 7.04%), viridiflorol (2.14 to 5.56%), α-pinene (1.55 to 6.17%), β-pinene (1.68 to 3.49%) and β-caryophyllene (1.06 to 5.59%). The essential oil composition of sage collections showed presence of larger quantities of the oxygenated terpenes (59.43 to 70.68%) as compared to monoterpene hydrocarbon (13.41 to 17.01%), sesquiterpene hydrocarbon (7.78 to 15.36%) and oxygenated sesquiterpenes (2.14 to 7.73%). The presence of comparatively high concentration of oxygenated compounds mainly thujones, 1,8-cineole and camphor in sage oils may be attributing its carminative, antispasmodic, antiseptic, and astringent properties. Hence, these sage collections may be exploited for various biological and therapeutic applications. Key words: Salvia officinalis, essential oil, composition, Lamiaceae, terpenes, thujones.

Intraspecific variation and cytotoxic evaluation of the essential oils from Oxandra sessiliflora R. E. Fries

For the first time, the chemical composition and cytotoxic evaluation of essential oils from leaves of Oxandra sessiliflora R. E. Fries (Annonaceae) has been reported. Leaves of O. sessiflora were collected in four different periods during the years 2010 (September and December) and 2011 (March and June). The essential oils, obtained by hydrodistillation procedures, were analyzed by Gas chromatography (GC) and Gas chromatography-Mass spectrometry (GC-MS). Chemically, the predominance of hydrocarbon sesquiterpenes was detected (57.54 to 75.06%), with germacrene D (17.12 to 32.20%) and biclyclogermacrene (7.95 to 18.91%) as the main compounds. These oils were also composed of monoterpenes (9.65 to 17.02%) and oxygenated sesquiterpenes (4.42 to 11.43%). Additionally, the essential oils obtained from leaves collected in September, 2010 and March, 2011 were tested in vitro against murine (B16F10-Nex2) and human melanoma (A2058), breast adenocarcinoma (MCF7), leukemia (HL-60), and cervical carcinoma (HeLa) cell lines. Since values of IC50 to HL-60 cells were determined as approximately 6 µg/mL in both tested oils, the results suggested that the essential oils and their compounds could be used as prototypes for the development of new medicines for the treatment of human leukemia. Key words: Oxandra sessiliflora, essential oil composition, intraspecific variation, in vitrocytotoxic potential.

Evaluation of HO<sub>x</sub> sources and cycling using measurement-constrained model calculations in a 2-methyl-3-butene-2-ol (MBO) and monoterpene (MT) dominated ecosystem

Abstract. We present a detailed analysis of OH observations from the BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen)-ROCS (Rocky Mountain Organic Carbon Study) 2010 field campaign at the Manitou Forest Observatory (MFO), which is a 2-methyl-3-butene-2-ol (MBO) and monoterpene (MT) dominated forest environment. A comprehensive suite of measurements was used to constrain primary production of OH via ozone photolysis, OH recycling from HO2, and OH chemical loss rates, in order to estimate the steady-state concentration of OH. In addition, the University of Washington Chemical Model (UWCM) was used to evaluate the performance of a near-explicit chemical mechanism. The diurnal cycle in OH from the steady-state calculations is in good agreement with measurement. A comparison between the photolytic production rates and the recycling rates from the HO2 + NO reaction shows that recycling rates are ~20 times faster than the photolytic OH production rates from ozone. Thus, we find that direct measurement of the recycling rates and the OH loss rates can provide accurate predictions of OH concentrations. More importantly, we also conclude that a conventional OH recycling pathway (HO2 + NO) can explain the observed OH levels in this non-isoprene environment. This is in contrast to observations in isoprene-dominated regions, where investigators have observed significant underestimation of OH and have speculated that unknown sources of OH are responsible. The highly-constrained UWCM calculation under-predicts observed HO2 by as much as a factor of 8. As HO2 maintains oxidation capacity by recycling to OH, UWCM underestimates observed OH by as much as a factor of 4. When the UWCM calculation is constrained by measured HO2, model calculated OH is in better agreement with the observed OH levels. Conversely, constraining the model to observed OH only slightly reduces the model-measurement HO2 discrepancy, implying unknown HO2 sources. These findings demonstrate the importance of constraining the inputs to, and recycling within, the ROx radical pool (OH + HO2 + RO2).

Emissions of BVOC from lodgepole pine in response to mountain pine beetle attack in high and low mortality forest stands

Abstract. In this screening study, biogenic volatile organic compound (BVOC) emissions from intact branches of lodgepole pine (Pinus contorta) trees were measured from trees at two forested sites that have been impacted differently by the mountain pine beetle (MPB), with one having higher mortality and the other with lower mortality. Differences in the amounts and chemical diversity of BVOC between the two sites and from apparently healthy trees versus trees in different stages of MPB attack are presented, as well as (for one site) observed seasonal variability in emissions. A brief comparison is made of geological and climatic characteristics as well as prior disturbances (both natural and man-made) at each site. Trees sampled at the site experiencing high MPB-related tree mortality had lower chemodiversity in terms of monoterpene (MT) emission profiles, while profiles were more diverse at the lower-mortality site. Also at the higher-mortality site, MPB-infested trees in various stages of decline had lower emissions of sesquiterpenes (SQTs) compared to healthy trees, while at the site with lower mortality, MPB-survivors had significantly higher SQT emissions during part of the growing season when compared to both uninfested and newly infested trees. SQT profiles differed between the two sites and, like monoterpene and oxygenated VOC profiles, varied through the season. For the low-mortality site in which repeated measurements were made over the course of the early summer–late fall, higher chemical diversity was observed in early- compared to late-season measurements for all compound classes investigated (MT, oxygenated VOC, and SQT), with the amount of change appearing to correlate to the MPB status of the trees studied. Emissions of 2-methyl-3-buten-2-ol (MBO) had a distinct seasonal signal but were not much different between healthy or infested trees, except in trees with dead needles, from which emissions of this compound were negligible, and in late-season MPB survivors, in which they were higher than in newly infested or uninfested trees. Emissions of SQT were significantly higher in the MPB survivors during both mid- and late-season sampling at the low-mortality site. The changes in emissions could have implications for regional air quality and climate through changes in ozone and aerosol distributions, although this study was designed as a preliminary screening effort and not enough individuals were sampled for all of the observed differences to be statistically demonstrated. Despite this, the compelling differences in emissions observed between the sites and individual trees with differing MPB-infestation statuses and the potential impacts these have on regional atmospheric chemistry argue for further research in this topic.

Seasonal variation in basal emission rates and composition of mono- and sesquiterpenes emitted from dominant conifers in Japan

Biogenic volatile organic compounds (BVOCs) are known to play an important role in atmospheric chemistry due to their high reactivity and high emission rates. Therefore, in recent decades, many efforts have been made to estimate the emission rates, composition and allocation of the BVOCs. Monoterpenes (MNTs) and sesquiterpenes (SQTs) are major groups of BVOCs and mainly emitted from coniferous trees. There is quite a few reports discussing the seasonality of basal emission rate, which is a normalized emission rate at a set of standard conditions (e.g. temperature, light intensity), of the BVOCs. Three field measurements were conducted using branch enclosure techniques to determine MNTs and SQTs emission measured from mature trees of Cryptomeria japonica and Chamaecyparis obtusa, which are the most dominant trees in Japan and account for about 40–50% of Japanese forest in leaf amount throughout the four seasons in southern Japan in 2010. The results are compared with the measurements for the same compound classes obtained at a suburban area of Tokyo, Japan in 2009. The seasonal variation in the basal emissions of MNTs from both tree species at Shiiba did not show significant seasonal changes. For both tree species, the variations in the basal emission of MNTs differ in the two sites, while those of SQTs showed relatively similar variations. Chemical composition of SQTs showed clear and continued seasonal variations, while MNTs did not show any clear seasonal variation for these tree species at both sites. It can be hypothesized that the emissions of BVOC classes (e.g. MNTs and SQTs) depend on leaf age. In this paper, we discuss about the seasonal variations in the basal emission rates and chemical compositions of BVOCs obtained from the two dominant coniferous tree species in Japan based on nine field measurement campaigns conducted at two different sites.

Chemical composition and antimicrobial activity of essential oils of different organs of three Artemisia species from Iran

In this study, the chemical composition of essential oils isolated from dried stems, leaves, and fruits of three wild sages from Northern Iran (Artemisia absinthium L., Artemisia annuaL., and Artemisia tschernieviana B) were investigated by a combination of gas chromatography (GC) and gas chromatography (GC)/mass spectrometry (MS). A total of 83 components were identified accounting for 93.51 to 100.00% of the oil composition. A. absinthium oils were characterized by high amounts of β-thujone (24.27 to 40.91%), 1,8-cineole (8.10 to 14.09%), and sabinene(8.35 to 10.05%). A. annua yielded an oils rich in camphor (10.54 to 24.12%), borneol (1.48 to 27.78%), and 1,8-cineole (8.03 to 11.71%). β -pinene (13.65 to 22.37%), limonene (7.69 to 13.65%), and cubenol (3.50 to 15.43%) were the main components in the essential oils of A. tschernieviana. The total numbers of volatile compounds identified from A. absinthium, A. annua, and A. tschernieviana were 58, 84, and 86, respectively. In A. absinthium and A. annua, monoterpens were higher than the sesquiterpens, and oxygenated monoterpene compounds were the main constituents, but in oils of A. tschernieviana, monoterpene hydrocarbons were the main constituents. The results of the antimicrobial activity of all essential oils showed that the oils had varying degrees of growth inhibition against the microorganisms tested. Key words: Artemisia absinthium, Artemisia annua, Artemisia tschernieviana,Compositae, essential oil composition, antimicrobial activity.

Cornoside A, a new monoterpenoid glucosid with an unusual skeleton from Cornus controvers

Cornoside A, a new monoterpenoid glucosid with an unusual skeleton from Cornus controvers

Efficiency of Agrobacterium transformation of pinene synthase gene isolated from kaffir lime in Arabidopsis thaliana

β-pinene, a monoterpene, was found as a major component of an essential oil extracted from fruit peel of kaffir lime ( Citrus hystrix ) known as Makrut. In this study, the pinene synthase gene ( PNS ) previously cloned from kaffir lime was constructed into a plant expression vector, pCAMBIA1305.1, and transformed into Arabidopsis thaliana . The kaffir lime PNS was replaced uidA (GUS) gene which was driven by CaMV35S promoter in the pCAMBIA1305.1 vector containing hygromycin resistance gene. After testing for appropriate hygromycin concentration, the PNS transgenic Arabidopsis mediated by Agrobacterium tumefaciens EHA105 were selected on 1/2MS containing 20 mg/l hygromycin for 10 days. The Arabidopsis seeds were collected from each transgenic lines of the 1 st –4 th generation (T0–T3) selected for hygromycin resistant. After selection, the percentage of seed survival of T0, T1, T2 and T3 transgenic Arabidopsis gradually increased at rate of 0.27, 45.17, 70.65 and 78.88, respectively. In addition, the kaffir lime PNS transgene was successfully integrated into the genome of all transgenic lines when detected by PCR. The obtained transgenic lines will be subjected to further study on the effects of this gene product to Arabidopsis essential oil components.

Synthesis of new monoterpene sulfonylimidazoles

Sulfonylimidazoles of monoterpenes of menthane, pinane, and carane nature were synthesized in 83-98% yields.

Stereoselective effects of monoterpenes on the microviscosity and curvature of model membranes assessed by DPH steady‐state fluorescence anisotropy and light scattering analysis

Here, we evaluated stereoselectivity in monoterpenes (MTs) ability to disturb membrane dynamics. Correlations between molecular structure and physicochemical properties of pinenes, menthols, and carvones enantiomers were investigated through cluster and principal component analysis. Therefore, MTs' concentration-dependent changes in light scattering and diphenylhexatriene (DPH) fluorescence polarization induced by MTs were measured on large unilamellar vesicles (LUVs) of dipalmitoylphosphatidylcholine. The behavior of the less polar compounds (hydrocarbons) was characterized by a membrane expansion (increase in light scattering), detectable within the low-concentration range. They remained in the membrane up to the highest concentrations tested exhibiting a concentration-dependent anisotropy decrease. Within the more polar terpenes (alcohols) prevailed a budding phenomenon with the production of small LUVs with roughly constant curvature (more evident at medium and high concentrations), which explains the slight change in microviscosity (DPH fluorescence anisotropy). These behaviors were compatible with the deeper localization within the membrane core of the formers compared with the latters as predicted from the corresponding polar charge distribution in their molecular structures. The enantioselectivity was expressed by neomenthol at low concentration and carvone at medium concentration. Inhibition and potentiation were evidenced, within the low-concentration range, by the racemic mixtures in neomenthol and β-pinenes, respectively.

Contributions of primary and secondary biogenic VOC tototal OH reactivity during the CABINEX (Community Atmosphere-Biosphere INteractions Experiments)-09 field campaign

Abstract. We present OH reactivity measurements using the comparative reactivity method with a branch enclosure technique for four different tree species (red oak, white pine, beech and red maple) in the UMBS PROPHET tower footprint during the Community Atmosphere Biosphere INteraction EXperiment (CABINEX) field campaign in July of 2009. Proton Transfer Reaction-Mass Spectrometry (PTR-MS) was sequentially used as a detector for OH reactivity and BVOC concentrations including isoprene and monoterpenes (MT) for enclosure air. Therefore, the measurement dataset contains both measured and calculated OH reactivity from well-known BVOC. The results indicate that isoprene and MT, and in one case a sesquiterpene, can account for the measured OH reactivity. Significant discrepancy between measured OH reactivity and calculated OH reactivity from isoprene and MT is found for the red maple enclosure dataset but it can be reconciled by adding reactivity from emission of a sesquiterpene, α-farnesene, detected by GC-MS. This leads us to conclude that no significant unknown BVOC emission contributed to ambient OH reactivity from these trees at least during the study period. However, this conclusion should be followed up by more comprehensive side-by-side intercomparison between measured and calculated OH reactivity and laboratory experiments with controlled temperature and light environments to verify effects of those essential parameters towards unknown/unmeasured reactive BVOC emissions. This conclusion leads us to explore the contribution towards ambient OH reactivity (the dominant OH sink in this ecosystem) oxidation products such as hydroxyacetone, glyoxal, methylglyoxal and C4 and C5-hydroxycarbonyl using recently published isoprene oxidation mechanisms (Mainz Isoprene Mechanism II and Leuven Isoprene Mechanism). Evaluation of conventionally unmeasured first generation oxidation products of isoprene and their possible contribution to ambient missing OH reactivity indicates that the ratio of OH reactivity from unmeasured products over OH reactivity from MVK + MACR is strongly dependent on NO concentrations. The unmeasured oxidation products can contribute ~7.2 % (8.8 % from LIM and 5.6 % by MIM 2 when NO = 100 pptv) of the isoprene contribution towards total ambient OH reactivity. This amount can explain ~8.0 % (9.7 % from LIM and 6.2 % from MIM 2) of missing OH reactivity, reported by Di Carlo et al. (2004) at the same site. Further study on the contribution from further generation of unmeasured oxidation products is needed to constrain tropospheric photochemical reactivity of BVOC that have important implications for both photochemical ozone and secondary organic aerosol formation.

Deposition fluxes of terpenes over grassland

Eddy covariance flux measurements were carried out for two subsequent vegetation periods above a temperate mountain grassland in an alpine valley using a proton-transfer-reaction - mass spectrometer (PTR-MS) and a PTR-time of flight - mass spectrometer (PTR-TOF). In 2008 and during the first half of the vegetation period 2009 the volume mixing ratios (VMRs) for the sum of monoterpenes (MTs) were typically well below 1 ppbv and neither MT emission nor deposition was observed. After a hailstorm in July 2009 an order of magnitude higher amount of terpenes was transported to the site from nearby coniferous forests causing elevated VMRs. As a consequence, deposition fluxes of terpenes to the grassland, which continued over a time period of several weeks without significant re-emission, were observed. For days without precipitation the deposition occurred at velocities close to the aerodynamic limit. In addition to monoterpene uptake, deposition fluxes of the sum of sesquiterpenes (SQTs) and the sum of oxygenated terpenes (OTs) were detected. Considering an entire growing season for the grassland (i.e., 1st of April to 1st of November), the cumulative carbon deposition of monoterpenes reached 276 mg C m-2. This is comparable to the net carbon emission of methanol (329 mg C m-2), which is the dominant non methane volatile organic compound (VOC) emitted from this site, during the same time period. It is suggested that deposition of monoterpenes to terrestrial ecosystems could play a more significant role in the reactive carbon budget than previously assumed.

Characterization of the volatiles and active components in ethanol extracts of fruits of Litsea cubeba (Lour.) by gas chromatography-mass spectrometry (GC-MS) and gas chromatography- olfactometry (GC-O)

Currently extracts fruits of Litsea cubeba (Lour.) (FLC) is mainly used as natural remedies, perfumery ingredients and food additives. This study reports characterization of the extracts from FLC, which widely distributes in southern China, Japan, and other parts of southeast of Asia. The ethanol extracts of FLC were analyzed by gas chromatography-mass spectrometry (GC-MS), GC-flame ionization detection (GC-FID), and GC-olfactometry (GC-O). A total of 29 compounds were identified and quantified. Among them, the predominant compounds in ethanol extracts of FLC were d-limonene (8.52%), α-citral (26.15%), β-citral (33.16%). It also contains abundant of hydrocarbon monoterpenes, monoterpenes oxide and aliphatic acids and esters. The most frequent descriptors of the ethanol extracts components assessed by GC-O were “citrus”, “lemon”, “sweet”, “spicy”, “pine”, “green”. p-Cymene, thujanol, d-limonene, linalool, caryophyllene, α-citral and β-citral are the most important contributors to the aroma of the extracts. Key words: Litsea cubeba, aroma, extracts, citral.

A COMPARISON OF VOLATILE COMPONENTS OF FLOWER OF PAGE MANDARIN OBTAINED BY ULTRASOUND-ASSISTED EXTRACTION AND HYDRODISTILLATION

Traditional hydrodistillation (HD) and ultrasound-assisted extraction method (UAE) have been compared and evaluated for their quantitative and qualitative compositions of the isolated essential oil from fresh page mandarin flowers. Thirty-eight flower components and twenty-nine flower components in the UAE and HD method, respectively including: aldehydes, alcohols, ketons, monoterpenes, sesquiterpenes and other components were indentified and quantified. The major flavor components of oil obtained by UAE were β-sinensal, α-sinensal, linalool, limonene, sabinene, ocimene, (z)-β-farnesene and E,E-α-farnesene. The major flavor components of oil obtained by HD were β-sinensal, α-sinensal, linalool, limonene, sabinene, ocimene and terpinene-4-ol. The UAE method offers important advantages over HD method, namely: provides a higher amount of oxygenated compounds. It offers also the possibility for a better reproduction of natural aroma of the essential oil from page mandarin flowers than the HD method. UAE method showed the highest content of aldehydes and alcohols. Since the aldehydes and alcohols content of citrus oil is considered as one of the more important indicators of high quality, method apparently has a profound influence on Page Mandarin oil quality. Key words: Page mandarin flower, ultrasound-assisted extraction, hydrodistillation, oxygenated components.

Evaluation of the antifungal effects of rosemary oil and comparison with synthetic borneol and fungicide on the growth of Aspergillus flavus

Rosemary (Rosmarinus officinalis L.) with more than 240 active pharmacological and nutritional compounds is important from the botanical point of view. Pharmacological studies show the antifungal properties of Rosemary plant. The essential oil analyses of the aerial parts of rosemary collected from Kerman province were obtained using gas chromatography and gas chromatography mass spectrometry. The study of antifungal effects of the oil sample tested against strain of Aspergillus flavus (PTCC = 5004) fungi by disc diffusion method via average inhibition zone. The results showed that yield of Rosemary oil from Kerman province was 3.2%. Forty-one compounds were identified in the essential oil concluded as 99.74% of the total oil. The major components were α-pinene (15.52%), camphor (11.66%), verbenone (11.10%) and 1, 8-cineole (10.63%). The results showed that essential oil from rosemary plant at 1, 1/2 and 1/4 oil dilutions exhibited strong antifungal activity than gentamycin antibiotic on A. flavus and exhibited moderate of borneol was at 10% dilution. Benomil fungicide at 10% dilution had no inhibitory effect on A. flavus. Large percentage antifungal activities of Rosemary oil are related with α-pinene of monoterpenes as the main compound. Key words: Rosmarinus officinalis L., essential oil, Aspergillus flavus, aflatoxin, borneol.

The effects of rootstock on the volatile flavor components of page mandarin (( Citrus reticulata var dancy × Citrus paradisi var dancan) × Citrus clemantina ) flower and leaf

The effects of rootstock on the volatile flavor components of page mandarin flower and leaf were investigated in this study. Flower flavor components were extracted by using ultrasound(US) water bath apparatus and eluted by n-pentane: diethylether(1:2) solvent and then analyzed by GC-FID and GC-MS. Leaf flavor components were extracted by using water distillation method and eluted by using n-hexane solvent and then analyzed by GC-FID and GC-MS. Fifty-two flower components and, sixty-nine leaf components including: aldehydes, alcohols, esters, ketones, monoterpenes, sesquiterpenes and other components were identified and quantified. The major flavor components were linalool, limonene, ocimene, -pinene, sabinene and myrcene. The flower and leaf oil from plants grown on Swingle Citrumelo and Yuzu showed the highest content of aldehydes. Since the aldehyde content of citrus oil is considered one of the more important indicators of high quality, rootstock apparently has a profound influence on Page mandarin flower and leaf oil quality. Key words: Page mandarin flower, page mandarin leaf, flavor components, rootstock, ultrasound, water-distillation

Chemical composition of Cymbopogon citratus essential oil and its effect on mycotoxigenic Aspergillus species

This study evaluated the antifungal activity of essential oil of Cymbopogon citratus (Poaceae) against five mycotoxigenic species of the genus Aspergillus (Aspergillus flavus, Aspergillus parasiticus, Aspergillus ochraceus, Aspergillus niger and Aspergillus fumigatus) isolated from maize samples. The oil of C. citratus was obtained by hydro-distillation and analysed by Gas Chromatography – Mass Spectrometry (GC-MS). The oil was dominated by monoterpene hydrocarbons which accounted for 94.25% of the total oil and characterised by a high percentage of geranial (39.53%), neral (33.31%), and myrecene (11.41%). The antifungal activity tests showed that the oil was active against all the five Aspergillus species. The extent of inhibition of fungal growth was dependent on the concentration of the oil. The activity of the oil against the mycotoxigenic fungi had Minimun Inhibitory Concentration (MIC) values ranging from 15 to 118 mg/ml. These results show that the essential oil of C. citratus has antifungal activities against fungi that are the producers of poisonous mycotoxins found in foods. This oil can be used in food preservation systems to inhibit the growth of moulds and retard subsequent mycotoxin production. Key words: A. flavus, A. fumigatus, A. niger, A. ochraceus, A. parasiticus, antifungal.

Chemical composition and antifungal activity of volatile components from woody terminal branches and roots of Tetraclinis articulate (Vahl.) Masters growing in Tunisia

The chemical composition of the volatile fractions obtained from distilled woody terminal branches and roots of Tetraclinis articulata (Vahl.) Masters was identified by Gas Chromatography- Flame ionization detectors (GC-FID) and Gas Chromatography-Coupled with Mass Spectrometry (GC-MS). Twenty compounds represented 83.7% of the essential oil from woody terminal branches and 29.2% from the roots. Nonan-1-ol was the main constituent present in the second fraction of the essential oil from woody terminal branches with the highest percentage of 75.22. Monoterpene hydrocarbons viz: α-terpinene (3.04), δ-carene (1.17) and β-ocimene (1.09) were the main compounds. In the fourth fraction of the essential oil from roots, the major compounds detected were Bornyl acetate (16.63), Camphene (1.59) and γ-cadinene (2.86). This fraction was mainly rich in oxygenate compounds (20.25) and sesquiterpene hydrocarbons (6.84). Furthermore, the oils were tested for their antifungal activity against five phytopathogenic fungi. These oils from woody terminal branches and roots of T. articulata (Vahl.) Masters were found to possess antifungal activity. Key words: Antifungal activity, Cupressaceae, essential oil, Nonan-1-ol, Tetraclinis articulata (Vahl.) Masters.