LMD and LC-MS-based chemical constituents and pharmacological effects assessment for two different processing methods of the root of Paeonia lactiflora Pall.

The plant of Paeonia lactiflora Pall. belongs to Ranunculaceae, and its root can be divided into two categories according to different processing methods, which included that one was directly dried without peeling the root of the P. lactiflora (PR), and the other was peeled the root of the P. lactiflora (PPR) after boiled and dried. To evaluate the difference of chemical components, UPLC-ESI-Q-Exactive Focus-MS/MS and UPLC-QQQ-MS were applied. The distribution of chemical components in different tissues was located by laser microdissection (LMD), especially the different ingredients. A total of 86 compounds were identified from PR and PPR. Four kind of tissues were isolated from the fresh root of the P. lactiflora (FPR), and 54 compounds were identified. Especially the content of gallic acid, albiflorin, and paeoniflorin with high biological activities were the highest in the cork, but they were lower in PR than that in PPR, which probably related to the process. To illustrate the difference in pharmacological effects of PR and PPR, the tonifying blood and analgesic effects on mice were investigated, and it was found that the tonifying blood and analgesic effects of PPR was superior to that of PR, even though PR had more constituents. The material basis for tonifying blood and analgesic effect of the root of P. lactiflora is likely to be associated with an increase in constituents such as paeoniflorin and paeoniflorin lactone after boiled and peeled. The study was likely to provide some theoretical support for the standard and clinical application.

Assessment of Melissa officinalis L. essential oil as an eco-friendly approach against biodeterioration of wheat flour caused by Tribolium castaneum Herbst.

The study reports efficacy of Melissa officinalis L. essential oil (MOEO) as a safe plant-based insecticide against Tribolium castaneum Herbst (TC) by induction of oxidative stress. MOEO nanoencapsulation in chitosan matrix was performed to enhance its bioefficacy. GC-MS analysis of MOEO depicted geranial (31.54%), neral (31.08%), and ß-caryophyllene (12.42%) as the major components. MOEO showed excellent insecticidal potential in contact (100% mortality at 0.157 µL/cm2) and fumigant bioassays (LC50 = 0.071 µL/mL air) and 100% repellency at concentration ≤ 0.028 µL/cm2. Increased reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), and decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) at the LC50 dose suggested significant oxidative stress on TC in MOEO treatment sets. The encapsulated MOEO exhibited enhanced activity as fumigant (LC50 = 0.048 µL/mL air) and showed significant antifeedant activity in situ (EC50 = 0.043 µL/mL). High LD50 value (13,956.87 µL/kg body weight of mice) confirmed favorable toxicological profile for non-target mammals. The findings depict potential of nanoencapsulated MOEO as an eco-friendly green pesticide against infestation of stored food by TC.

Assessment of the phytochemical profiles of novel hop (Humulus lupulus L.) cultivars: A potential route to beer crafting.

This study investigated the volatile phytochemical diversity of 30 samples obtained from experimental hybrid and commercial H. lupulus L. plants. Essential oils distilled from these samples were analysed by high resolution gas chromatography coupled with accurate mass time-of-flight mass spectrometry (GC-accTOFMS). A total of 58 secondary metabolites, mainly comprising 18 esters, 6 monoterpene hydrocarbons, 2 oxygenated monoterpenes, 20 sesquiterpene hydrocarbons, 7 oxygenated sesquiterpenes, and 4 ketones, were positively or tentatively identified. A total of 24 metabolites were detected in all samples, but commercial cultivars (selected for brewing performance) had fewer compounds identified compared to experimental genotypes. Chemometrics analyses enabled distinct differentiation of experimental hybrids from commercial cultivars, discussed in terms of the different classes of compounds present in different genotypes. Differences among the mono- and sesquiterpenoids, appear to be related to either: i) the genetic origin of the plants; or ii) the processes of bioaccumulation of the identified secondary metabolites.

Application of near-infrared spectroscopy for the rapid quality assessment of Radix Paeoniae Rubra.

Near-infrared (NIR) spectroscopy with multivariate analysis was used to quantify gallic acid, catechin, albiflorin, and paeoniflorin in Radix Paeoniae Rubra, and the feasibility to classify the samples originating from different areas was investigated. A new high-performance liquid chromatography method was developed and validated to analyze gallic acid, catechin, albiflorin, and paeoniflorin in Radix Paeoniae Rubra as the reference. Partial least squares (PLS), principal component regression (PCR), and stepwise multivariate linear regression (SMLR) were performed to calibrate the regression model. Different data pretreatments such as derivatives (1st and 2nd), multiplicative scatter correction, standard normal variate, Savitzky-Golay filter, and Norris derivative filter were applied to remove the systematic errors. The performance of the model was evaluated according to the root mean square of calibration (RMSEC), root mean square error of prediction (RMSEP), root mean square error of cross-validation (RMSECV), and correlation coefficient (r). The results show that compared to PCR and SMLR, PLS had a lower RMSEC, RMSECV, and RMSEP and higher r for all the four analytes. PLS coupled with proper pretreatments showed good performance in both the fitting and predicting results. Furthermore, the original areas of Radix Paeoniae Rubra samples were partly distinguished by principal component analysis. This study shows that NIR with PLS is a reliable, inexpensive, and rapid tool for the quality assessment of Radix Paeoniae Rubra.

Assessment of safe bioactive doses of Foeniculum vulgare Mill. essential oil from Portugal.

This study was designed to evaluate the antifungal activity of Foeniculum vulgare essential oil; concomitantly, the safety of bioactive doses was also unveiled, for the first time, in several mammalian cells. The chemical characterisation was made by GC and GC-MS. Antifungal activity was evaluated against yeasts, dermatophytes and Aspergillus strains and germ tube inhibition assay was evaluated using Candida albicans. Cell viability was assessed by the MTT assay. The main constituents of the oil are E-anetol (47%), α-phellandrene (11%), α-pinene (10.1%) and fenchone (10.8%). The oil was more active against Cryptococcus neoformans and C. albicans (MICs 0.32-0.64 µL/mL) and the filamentation of C. albicans was totally inhibited with 0.08 µL/mL. The oil is safe for keratinocytes, hepatocytes and fibroblasts in concentrations up to 1.25 µL/mL, and to macrophages up to 0.64 µL/mL. These findings highlight safe bioactive concentrations that should be deeper investigated for further application in pharmaceutical industry.

Essential Oil from Sweet Potato Vines, a Potential New Natural Preservative, and an Antioxidant on Sweet Potato Tubers: Assessment of the Activity and the Constitution.

Pathogenic fungi and oxidation are the major factors that cause the deterioration of sweet potatoes and also cause the loss of quality that makes consumption unsafe. In the present study, the in vitro results demonstrate that the essential oil from sweet potato vines exhibits significantly enhanced activity compared to that of the control. Furthermore, the essential oil can actively inhibit the growth of some common microorganisms inducing pathogenic bacteria and fungi (inhibition rates above 50% at low concentrations). A total of 31 constituents were identified using GC-MS and confirmed that linalool and p-hydroxybenzoic acid are the major active ingredients. The experiment involving actual tubers showed that the essential oil could retains its quality and effectiveness again the fungus disease. This suggests that it could be used in the food industry to increase the shelf life of stored produce (tubers) to ensure food safety without the use of additives or preservatives.

Genetic variability in G2 and F2 region between biological clones of human respiratory syncytial virus with or without host immune selection pressure

Human respiratory syncytial virus (HRSV) is an important respiratory pathogens among children between zero-five years old. Host immunity and viral genetic variability are important factors that can make vaccine production difficult. In this work, differences between biological clones of HRSV were detected in clinical samples in the absence and presence of serum collected from children in the convalescent phase of the illness and from their biological mothers. Viral clones were selected by plaque assay in the absence and presence of serum and nucleotide sequences of the G2 and F2 genes of HRSV biological clones were compared. One non-synonymous mutation was found in the F gene (Ile5Asn) in one clone of an HRSV-B sample and one non-synonymous mutation was found in the G gene (Ser291Pro) in four clones of the same HRSV-B sample. Only one of these clones was obtained after treatment with the child's serum. In addition, some synonymous mutations were determined in two clones of the HRSV-A samples. In conclusion, it is possible that minor sequences could be selected by host antibodies contributing to the HRSV evolutionary process, hampering the development of an effective vaccine, since we verify the same codon alteration in absence and presence of human sera in individual clones of BR-85 sample.

Assessment of Cymbopogon citratus (DC.) stapf essential oil as herbal preservatives based on antifungal, antiaflatoxin, and antiochratoxin activities and in vivo efficacy during storage.

Thirty-five randomly collected samples of stored table grapes (Vitis vinifera L.) from different markets of Gorakhpur city, Uttar Pradesh, India, revealed occurrence of 11 types of fungi. Of which, Aspergillus flavus, Aspergillus niger, and Aspergillus ochraceus were dominant causing severe decay of grapes with 58%, 52%, and 67% incidence, respectively. On screening of 15 essential oils at 0.33 µL/mL, Cymbopogon citratus oil caused 100% mycelial inhibition against aforesaid dominant fungi. Oil was fungistatic at 0.29 µL/mL and exhibited broad fungitoxicity against other fruit rotting fungi associated with collected samples. C. citratus oil completely inhibited the growth and mycotoxin (AFB1 and OTA) secretion of the aflatoxigenic and ochratoxigenic strains of A. flavus, A. niger, and A. ochraceus at 0.8 µL/mL. E-Citral (52.9%) and Z-Citral (39.38%) were the major components of C. citratus oil during gas chromatography and gas chromatography-mass spectrometry analysis. Application of 200 and 300 µL of C. citratus oil on 1 kg of stored grapes showed enhancement of shelf life up to 10 d. The oil did not exhibit any phytotoxic effect on fruits. These results confirm that C. citratus oil could be a natural alternative to commercial fungicide for control of fruit rotting fungi of stored grapes.

Pomegranate juice adulteration by addition of grape or peach juices.

BACKGROUND: Pomegranate juice has gained a high reputation for its health properties and consequently is now a highly demanded product. However, owing to the limited production and high price of fresh pomegranates, adulteration of pomegranate juice seems to be happening. Hence it is imperative to establish criteria for detecting adulteration. RESULTS: Addition of grape juice significantly increased the contents of Ca, Mg and Fe and especially tartaric acid and proline and simultaneously decreased the content of K. Addition of peach juice up to 10% (v/v) only resulted in a significant increase in sucrose content. Regarding the volatile composition, adulteration of pomegranate juice with grape juice resulted in significant increases in acetic acid, isoamyl butyrate and especially 1-hexanol and linalool, while adulteration with peach juice resulted in significant increases in butyl acetate, isobutyl butyrate, benzyl acetate and especially isoamyl butyrate. CONCLUSION: The control protocols used in this study can serve as a basis for identification of pomegranate juice adulteration. It is important to highlight that it is necessary to simultaneously analyze and have results from several parameters to conclude that a particular pomegranate juice has been adulterated by mixing with another fruit juice.

Changes in growth, essential oil yield and composition of geranium (Pelargonium graveolens L.) as affected by growing media.

BACKGROUND: Using proper growing medium is known to be an effective way to improve crop growth and yield. However, the effects of growing media on geranium essential oil have scarcely ever been examined in detail. In this research, the effects of different growing media (soil, sand, pumice, perlite and perlite + cocopeat) on growth, oil yield and composition of geranium were studied. RESULTS: Growth was significantly improved in soilless-grown plants compared with soil-grown plants. Oil yield of soilless-grown plants (except for pumice) was about threefold higher than that of soil-grown plants. The increase in oil yield was correlated with higher leaf dry weight (r² = 0.96), as oil content was not affected. The citronellol/geranium ratio of oil was clearly affected by growing media, ranging from 5:1 in soil culture to 3:1 in soilless culture. The latter is acceptable for perfumery. CONCLUSION: Compared with soil, soilless media could produce higher yields of high-quality geranium oil that fits market requirements. Growth, oil yield and composition of plants grown in sand (a cheap and abundant growing medium) were not significantly different from those of plants grown in perlite and perlite + cocopeat.

Assessment of dietary exposure to flavouring substances via consumption of flavoured teas. Part 1: occurrence and contents of monoterpenes in Earl Grey teas marketed in the European Union.

Estimations of dietary exposure via the consumption of flavoured foods play a central role in the safety evaluation of flavouring substances. To assess uncertainties, actual data regarding the occurrence and concentration levels of flavouring substances were determined in commercially available flavoured foods, using Earl Grey tea as an example. The contents of the consistently occurring monoterpenes linalyl acetate, linalool, limonene, ß-pinene and γ-terpinene were determined in 90 tea samples purchased in 10 European Union member states. Rather narrow frequency distributions were observed for the major compounds linalyl acetate and linalool. The factors (1) country of purchase, (2) source of the products (national/international brands versus private label brands versus speciality tea shops), and (3) enantiomeric purities of the flavouring substances had no significant impact on the contents of the flavouring substances. Only in teas sold as loose leaves were the median contents of linalyl acetate and linalool (66% and 39%, respectively) higher than in teas offered in tea bags. Significant losses of flavouring substances were observed on storage of teas, indicating an impact of the type of packaging and the flavouring technology on the contents of flavouring substances in the product finally consumed.

Stability assessment of gas mixtures containing monoterpenes in varying cylinder materials and treatments.

Studies of climate change increasingly recognize the diverse influences exerted by monoterpenes in the atmosphere, including roles in particulates, ozone formation, and oxidizing potential. Measurements of key monoterpenes suggest atmospheric mole fractions ranging from low pmol/mol (parts-per-trillion; ppt) to nmol/mol (parts-per-billion; ppb), depending on location and compound. To accurately establish the mole fraction trends, assess the role of monoterpenes in atmospheric chemistry, and relate measurement records from many laboratories and researchers, it is essential to have good calibration standards. The feasibility of preparing well-characterized, stable gas cylinder standards for monoterpenes at the nmol/mol level was previously tested using treated (Aculife IV) aluminum gas cylinders at NIST. Results for 4 of the 11 monoterpenes, monitored versus an internal standard of benzene, indicated stability in these treated aluminum gas cylinders for over 6 months and projected long-term (years) stability. However, the mole fraction of the key monoterpene ß-pinene decreased, while the mole fractions of α-pinene, d-limonene (R-(+)-limonene), p-cymene, and camphene (a terpene not present in the initial gas mixture) increased, indicating a chemical transformation of ß-pinene to these species. A similar pattern of decreasing mole fraction was observed in α-pinene where growth of d-limonene, p-cymene, and camphene has been observed in treated gas cylinders prepared with a mixture of just α-pinene and benzene as the internal standard. The current research discusses the testing of other cylinders and treatments for the potential of long-term stability of monoterpenes in a gas mixture. In this current study, a similar pattern of decreasing mole fraction, although somewhat improved short-term stability, was observed for ß-pinene and α-pinene, with growth of d-limonene, p-cymene, and camphene, in nickel-plated carbon steel cylinders. ß-Pinene and α-pinene showed excellent stability at over 6 months in aluminum cylinders treated with a different process (Experis) than used in the original study.

What happens if people start drinking mouthwash as surrogate alcohol? A quantitative risk assessment.

Mouthwash ingestion has been observed in settings of restricted availability to alcoholic beverages such as in hospitals, prisons or military establishments. The literature offers limited evidence that ingredients of mouthwash may have health effects above the effects of ethanol. This study provides a quantitative risk assessment based on analysis of 30 mouthwash samples. All investigated brands contained alcohol, most of them menthol (93%), eucalyptol (90%), benzoic acid (87%), methyl salicylate (67%), and thymol (30%). For low risk drinking scenarios with average levels, only ethanol will exceed acceptable daily intakes (ADI). In worst case scenarios for alcohol dependent consumers ingesting 100g ethanol per day in the form of mouthwash, methyl salicylate will also exceeded the ADI by a factor of 17. The margin of exposure (MOE) for methyl salicylate, benzoates and thymol was below 100 for average scenarios, and below 10 for worst case scenarios, but ethanol is still the most toxic ingredient with MOE below 1. The occasional or even chronic ingestion of mouthwash may not cause health effects except the effects of ethanol alone. Only in extreme exposures, ingredients such as thymol or methyl salicylate could exacerbate the effects of ethanol, especially by contributing to metabolic acidosis.

Workplace concentrations and exposure assessment of monoterpenes in rosemary- and lavender-growing greenhouses.

OBJECTIVES: Monoterpenes can positively or negatively affect human health depending on their concentrations. To assess the atmospheric risk for greenhouse workers, monoterpene concentrations and personal exposure in herb-growing greenhouses were measured. METHODS: Monoterpene concentrations in a commercial greenhouse, where rosemary (Rosmarinus officinalis L.) and lavender (Lavandula angustifolia L.) were grown in pots, were measured every 4 hours on 11 days spread across a year. In a small experimental greenhouse, typical horticultural tasks were conducted to determine the factors increasing monoterpene concentrations. RESULTS: Concentrations of α-pinene, camphene, ß-pinene, limonene and cineole in the farmer's greenhouse were higher in winter than in summer because of longer ventilation periods of the greenhouse in summer. Further, the concentrations of these compounds were high (but <2 parts per billion in volume [ppbv]) when horticultural tasks were conducted inside the greenhouse. In a small experimental greenhouse, moving pots and cutting shoots increased ambient monoterpene concentrations to 10 ppbv. Spraying water also increased monoterpene concentrations but to a lesser extent. When performing tasks, greenhouse workers were exposed to monoterpene concentrations 2-3 times higher than the concentration in the ambient greenhouse air. CONCLUSIONS: Our measurement results reveal that monoterpene emissions are stimulated by horticultural tasks, even by spraying water. Our calculation result suggests that if ventilation is limited, the concentrations can reach levels high enough to cause sensory irritation in greenhouse workers. Greenhouse workers should be cautious when performing tasks for hours in tightly closed herb-growing greenhouses.

Identification of multiple constituents in the traditional Chinese medicine formula Zhi-zi-chi decoction and rat plasma after oral administration by liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry.

RATIONALE: Liquid chromatography (LC) coupled to positive electrospray ionization (ESI) tandem mass spectrometry (MS/MS) employing a time-of-flight tandem mass spectrometer was established to identify multi-components of Zhi-zi-chi decoction, a traditional Chinese medicine formula, and the constituents in rat plasma after oral administration of Zhi-zi-chi decoction. METHODS: The LC separation was achieved on a C(18) column. The mobile phase consisted of acetonitrile/0.2% formic acid with gradient program. The quadrupole time-of-flight (Q-TOF) mass spectrometer was operated in the positive ion mode with an electrospray ionization source (ESI+). The capillary voltage of the ion source was set at 4500 V and the capillary exit was 90 V. The nebulizer pressure was maintained at 1.2 bar. Hexapole radio frequencies 1 and 2 were set to 200 Vpp and 250 Vpp, respectively. RESULTS: A total 47 compounds in the Zhi-zi-chi decoction and 24 constituents in rat plasma after oral administration of Zhi-zi-chi decoction were identified. Of the 47 detected compounds in the Zhi-zi-chi decoction, 15 were identified by comparing the retention time and MS data with that of reference compounds and the rest were identified by MS analysis and retrieving the reference literature. Of the identified 24 compounds in rat plasma, 19 were the original form of the compounds absorbed from the 47 detected compounds, and the other five were the metabolites of the compounds existing in the Zhi-zi-chi decoction. CONCLUSIONS: A fast and sensitive LC/Q-TOF MS method has been developed and successfully utilized to screen the active ingredients of a Chinese medical formula, Zhi-zi-chi decoction, for the first time. The results indicated that the 24 compounds identified in rat plasma were the potential active ingredients of Zhi-zi-chi decoction, which provided helpful chemical information for further pharmacology and active mechanism research on Zhi-zi-chi decoction and other traditional Chinese medicines.

Comprehensive assessment of antioxidant activity of essential oils.

UNLABELLED: Essential oils have been studied for their unique ability to act as antioxidants. Antioxidant activities of 423 essential oils of 48 different botanical families were evaluated for their antioxidant activities as free radical scavenging agents using the 1,1-diphenyl-2-picrylhydrazyl method. Seventy-three oils showed 50% or more inhibition at a concentration of 1.25 mg/mL. The 73 most active oil samples were further evaluated for their scavenging activities using series of dilutions to estimate their EC(50) . The EC(50) of the 73 most active oils ranged from 4 to 2000 µg/mL. Oils having an EC(50) of less than 300 µg/mL (20 selected samples) were subjected to ß-carotene bleaching antioxidant activity test and more detailed analysis including thin layer chromatography, gas chromatography/mass spectrometry, high performance liquid chromatography and bioautography. Essential oils of the botanical families Lamiaceae and Myrtaceae were the most effective antioxidants. Thymol and carvacrol were the major constituents in most of the essential oils of the family Lamiaceae and eugenol was the major terpene in all of the essential oils of the family Myrtaceae. PRACTICAL APPLICATIONS: Supplementation of food with spices containing essential oils may counteract and retard the process of oxidative damage, lipid oxidation and elevate antioxidant activity of the final product.

Volatile aroma components and antioxidant activities of the flavedo peel extract of unripe Shiikuwasha (Citrus depressa Hayata).

UNLABELLED: The flavedo peel extracts of unripe Shiikuwasha (Citrus depressa Hayata) fruits were extracted using steam distillation (SD) or a cold-press (CP) system. Volatile aroma content and composition were determined using gas chromatography (GC) and each compound was identified using gas chromatography-mass spectrophotometry (GC-MS). The major constituents of the extracts were monoterpene hydrocarbons (91.75-93.75%[709.32-809.05 mg/100 g of fresh flavedo peel]) including limonene (43.08-45.13%[341.46-379.81 mg/100 g of fresh flavedo peel]), γ-terpinene (27.88-29.06%[219.90-245.86 mg/100 g of fresh flavedo peel]), and p-cymene (8.13-11.02%[61.47-97.22 mg/100 g of fresh flavedo peel]). The extraction process used was determined to be a decisive factor that affects the composition of key citrus aroma components, as well as the antioxidant activities of the Shiikuwasha fruit. Antioxidant capabilities of the extracts were examined by assay of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and ß-carotene bleaching inhibition. The cold-press extraction system may better retain the total phenolic content of the flavedo peel and display superior antioxidant activities, compared to the steam distillation extraction method. PRACTICAL APPLICATION: Shiikuwasha (Citrus depressa Hayata) is a type of small citrus fruit, and has been used as raw material for beverage and food additive productions in Japan. It had a unique aroma composition in which the limonene content of its peels is lower than that of other commonly known citrus peels. The present study detailed the volatile aroma composition, as well as antioxidant capabilities of Shiikuwasha peel extracts of different extraction methods, that are cold-press and steam distillation methods. The results of this study may provide a basis for selection of Shiikuwasha peel extracts in food industry for citrus flavor production.

Multidimensional enantio gas chromtography/mass spectrometry and gas chromatography-combustion-isotopic ratio mass spectrometry for the authenticity assessment of lime essential oils (C. aurantifolia Swingle and C. latifolia Tanaka).

This article focuses on the genuineness assessment of Lime oils (Citrus aurantifolia Swingle and C. latifolia Tanaka), by Multi Dimensional Gas Chromatography (MDGC) to determine the enantiomeric distribution of α-thujene, camphene, ß-pinene, sabinene, α-phellandrene, ß-phellandrene, limonene, linalool, terpinen-4-ol, α-terpineol and by gas chromatography-combustion isotope ratio mass spectrometry (GC-C-IRMS) to determine the isotopic ratios of α-pinene, ß-pinene, limonene, α-terpineol, neral, geranial, ß-caryophyllene, trans-α-bergamotene, germacrene B. To the author's knowledge this is the first attempt to assess the authenticity and differentiate Persian Lime from Key lime oils by GC-C-IRMS. The results of the two analytical approaches were compared. The simultaneous use of the two techniques provides more reliable capability to detect adulteration in Citrus essential oils. In fact, in some circumstance only one of the two techniques allows to discriminate adulterated or contaminated oils. In cases where only small anomalies are detected by the two techniques due to subtle adulterations, their synergic use allows to express judgments. The advantage of both techniques is the low number of components the analyst must evaluate, reducing the complexity of the data necessary to deal with. Moreover, the conventional analytical approach based on the evaluation of the whole volatile fraction can fail to reveal the quality of the oils, if the adulteration is extremely subtle.

Effect of distillation waste water and plant hormones on spearmint growth and composition.

BACKGROUND: Distillation waste water (DWW) is a by-product from steam distillation of essential-oil crops; and currently, it is discharged into streams and rivers. The effects of DWW from 13 essential-oil crops, extracts from two alkaloid-containing species, and three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) were evaluated on productivity, essential-oil content and composition of spearmint (Mentha spicata L.) cv. 'Native'. RESULTS: Spearmint plant height was increased by the application of GA3 and Melissa officinalis DWW but suppressed by the application of Rosmarinus officinalis and Tagetes lucida DWW. Generally, MJ, GA3 and M. officinalis and Mentha arvensis DWW increased dry yields. The concentration of L-carvone in the oil ranged from 550 g kg(-1) (with Monarda citriodora DWW) to 670 g kg(-1) (with T. lucida DWW). M. citriodora DWW reduced the concentration of L-carvone in the oil by 23% relative to the control. CONCLUSION: Results suggest that DWW from essential-oil crops may affect monoterpene synthesis in M. spicata and, hence, may have a direct effect on the essential oil composition. DWW from essential-oil crops may be used as a growth promoter and modifier of the essential oil composition of spearmint.

Temperature-dependent release of volatile organic compounds of eucalypts by direct analysis in real time (DART) mass spectrometry.

A method is described for the rapid identification of biogenic, volatile organic compounds (VOCs) emitted by plants, including the analysis of the temperature dependence of those emissions. Direct analysis in real time (DART) enabled ionization of VOCs from stem and leaf of several eucalyptus species including E. cinerea, E. citriodora, E. nicholii and E. sideroxylon. Plant tissues were placed directly in the gap between the DART ionization source skimmer and the capillary inlet of the time-of-flight (TOF) mass spectrometer. Temperature-dependent emission of VOCs was achieved by adjusting the temperature of the helium gas into the DART ionization source at 50, 100, 200 and 300 degrees C, which enabled direct evaporation of compounds, up to the onset of pyrolysis of plant fibres (i.e. cellulose and lignin). Accurate mass measurements facilitated by TOF mass spectrometry provided elemental compositions for the VOCs. A wide range of compounds was detected from simple organic compounds (i.e. methanol and acetone) to a series of monoterpenes (i.e. pinene, camphene, cymene, eucalyptol) common to many plant species, as well as several less abundant sesquiterpenes and flavonoids (i.e. naringenin, spathulenol, eucalyptin) with antioxidant and antimicrobial properties. The leaf and stem tissues for all four eucalypt species showed similar compounds. The relative abundances of methanol and ethanol were greater in stem wood than in leaf tissue suggesting that DART could be used to investigate the tissue-specific transport and emissions of VOCs.