The effect of chlorophyll on the enzyme-linked immunosorbent assay (ELISA) of procymidone in vegetables and the way to overcome the matrix interference.

BACKGROUND: There is now an increasing demand for the immunoassay of procymidone residue in foodstuffs. However, the matrix interference could significantly affect the analysis. Till now there is no detailed information on the source of the interference and the mechanism involved, which greatly limits the real application of these techniques. RESULTS: Significant matrix effect was observed in the enzyme-linked immunosorbent assay (ELISA) of procymidone in negative vegetable samples (leek, broccoli and cucumber). By the investigation with both vegetable extracts and standard solutions, the chlorophyll was confirmed as an important source of the matrix effect. Therefore, a new strategy was proposed for the pretreatment based on the exploitation of 5-sulfosalicylic acid. It was demonstrated to effectively eliminate chlorophyll and exhibited little effect on procymidone and the competitive indirect ELISA (ci-ELISA) performance. The established technique was validated with different vegetables. With the spiking concentration of procymidone investigated, the recovery rate of ci-ELISA was 71.52-120.37%, and the relative standard deviation was 4.05-17.61%. CONCLUSION: Chlorophyll was for the first time illuminated as an important source of matrix interference to the immunoassay of procymidone in vegetables. A new pretreatment based on 5-sulfosalicylic acid was established to remove chlorophyll and therefore eliminate the matrix effect. Validated with different vegetable samples, the new technique was demonstrated much better efficiency in comparison to conventional methods, which indicated its promising application for the development of immunoassays of herb-origin samples. © 2021 Society of Chemical Industry.

Comparison the dissipation behaviors and exposure risk of carbendazim and procymidone in greenhouse strawberries under different application method: Individual and joint applications.

The dissipation behaviors and exposure risks of individual and joint application of procymidone and carbendazim in greenhouse strawberries were studied. The initial concentrations were similar after individual or joint applications, while the dissipation half-lives and finial concentrations were significantly different. After joint application, the dissipation half-lives of procymidone and carbendazim were 12.9 and 16.0 days, respectively, which were about 1.8 times higher than those after individual application. Furthermore, the final residues under joint application condition were 1.8-3.5 times higher than those under individual application condition. The joint application decreased the dissipation rates of procymidone or carbendazim in strawberries, and increased the final residue concentrations. The dietary intake risks of procymidone and carbendazim (whether applied individually or jointly) were no higher than 0.12, which were acceptable for human health. This work would shed a light for the guidance of the joint application and risk assessment of the typical fungicides in strawberry.

The repellency and toxicity effects of essential oils from the Libyan plants Salvadora persica and Rosmarinus officinalis against nymphs of Ixodes ricinus.

Essential oils extracted from the leaves of Libyan Rosemary (Rosmarinus officinalis L.), and Miswak (Salvadora persica L.) were evaluated for their acaricidal and repellent effects on Ixodes ricinus L. nymphs (Acari: Ixodidae) using a bioassay based on an 'open filter paper method'. Rosmarinus officinalis leaf essential oil diluted to 0.5 and 1 µl/cm2 in acetone exhibited, respectively, 20 and 100% tick mortality after about 5 h of exposure. A total of 50 and 95% of I. ricinus nymphs were killed by direct contact with the oil when exposed to lethal concentrations (LC) of 0.7 µl/cm2 (LC50) and 0.95 µl/cm2 (LC95), respectively. The LC50 (0.5 µl/cm2) was reached before the end of the first 24 h of exposure time (ET), as tick mortality at 24 h was 60%. Salvadora persica leaf essential oil at 1 µl/cm2 showed a significant repellency effect against I. ricinus nymphs at 1.5 h ET. A 95% repellency was observed at a repellent concentration (RC95) of 1 µl/cm2 of S. persica, but no significant mortality was recorded at this dose of S. persica oil. Gas chromatography-mass spectrometry analyses showed that the main monoterpenes in both oils were 1,8-cineol, α-pinene, and ß-pinene, although in markedly different proportions. These results suggest that essential oils have substantial potential as alternative approaches for I. ricinus tick control.

Chemical Composition and Biological Activity of Five Essential Oils from the Ecuadorian Amazon Rain Forest.

The chemical composition and biological activity of essential oils isolated from the leaves of Siparuna aspera, Siparuna macrotepala, Piper leticianum, Piper augustum and the rhizome of Hedychium coronarium were evaluated. These species are used medicinally in different ways by the Amazonian communities that live near the Kutukú mountain range. Chemical studies revealed that the main components for the two Siparuna species were germacrene D, bicyclogermacrene, α-pinene, δ-cadinene, δ-elemene, α-copaene and ß-caryophyllene; for the two Piper species ß-caryophyllene, germacrene D, α-(E,E)-farnesene, ß-elemene, bicyclogermacrene, δ-cadinene and for H. coronarium 1,8-cineole, ß-pinene, α-pinene and α-terpineol. The antioxidant activity of all essential oils was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), photochemiluminescence (PCL) quantitative assays, and DPPH and ABTS bioautographic profiles, with different results for each of them. Antimicrobial activity studies were carried out on three yeasts, six Gram positive and four Gram negative bacteria, by means of the disc diffusion method. The essential oil of H. coronarium showed the most relevant results on L. grayi, K. oxytoca and S. mutans, P. augustum and P. leticianum on S. mutans. An antibacterial bioautographic test for H. coronarium was also carried out and highlighted the potential activity of terpinen-4-ol and 1,8-cineole.

Accurate and Sensitive Determination Method for Procymidone and Chlorflurenol in Municipal Wastewater, Medical Wastewater and Irrigation Canal Water by GC-MS After Vortex Assisted Switchable Solvent Liquid Phase Microextraction.

In this study, the detection power of a gas chromatography mass spectrometer (GC-MS) for procymidone and chlorflurenol was significantly enhanced using switchable solvent liquid phase microextraction (SS-LPME) as a preconcentration tool. This was achieved by a comprehensive optimization of significant parameters to the SS-LPME method such as switchable solvent amount, concentration and amount of sodium hydroxide, pH effect and mixing effect. The optimum experimental conditions obtained were used to determine analytical figures of merit for the analytes. The limits of detection obtained were 0.44 and 2.9 ng/mL for procymidone and chlorflurenol, respectively. The optimum method was applied to water sampled from an irrigation canal and two wastewater samples. The samples were spiked at two concentrations and the percent recovery results obtained ranged between 86 and 115% for both analytes. The recovery results together with the low standard deviations recorded validated the method as accurate and precise.

A qHNMR method for simultaneous quantification of terpenoids from Ferula ovina (Boiss.) Boiss roots.

Ferula ovina (Boiss.) Boiss is one of the most important endemic medicinal plants in Iran, which has three main terpenoid compounds including ferutinin, stylosin and tschimgine. Ferutinin is the strongest natural phytoestrogen that has agonistic activity on estrogen receptors, particularly α-receptors. To determine the amount of ferutinin in F. ovina roots, we firstly used HPLC-UV method. In the HPLC method, the resolution of ferutinin from the two other compounds, stylosin and tshimgine, was poor. Therefore, we decided to use qHNMR method for simultaneous quantification of ferutinin, stylosin and tshimgine in the plant roots. Quantitative 1H-NMR (qHNMR) was carried out based on the relative ratio of signal integration of each compound [(H-1 for tschimgine (δH 4.94-5.03), OCH3 for stylosin (δH 3.8), and H-9 for ferutinin (δH 5.58)] to certain amount of the internal standard dimethyl sulfone (DMSO2). The qHNMR method showed good precision (intra-day RSD ≤ 2.31%, inter-day RSD ≤ 2.72%), linearity (in the ranges of 1.3-10.41, 1.2-9.7 and 1.1-9.02 mg/mL with correlation coefficients at 0.9991), repeatability (RSD ≤ 2.99%) and stability (RSD ≤ 2.4%) for the quantification of the compounds. This work confirmed that qHNMR represents a feasible alternative to high-performance liquid chromatography based methods for simultaneous quantification of ingredients in plant extracts.

Compartment specific chiral pinene emissions identified in a Maritime pine forest.

To track unknown sources and sinks of volatile organic compounds (VOCs) inside forest canopies we measured diel cycles of VOC exchanges in a temperate maritime forest at the branch, stem and ground level with special focus on the chiral signatures of pinenes. All compartments released day and night α- and ß-pinene as major compounds. In addition, strong light dependent emissions of ocimene and linalool from branches occurred during hot summer days. In all compartments the overall emission strength of pinenes varied from day to day spanning 1 to 2 orders of magnitude. The highest pinene emissions from ground and stem were observed during high moisture conditions. Despite this variability stem emissions consistently expressed a different chiral composition than branch emissions, the former containing a much larger fraction of (-)-enantiomers than the latter. Pinene emissions from dead needle litter and soil were mostly enriched in (-)-enantiomers, while the chiral signatures of the ambient air inside the forest showed mostly intermediate levels compared to the emission signatures. These findings suggest that different organ-specific pinene producing enzymes exist in Maritime pine, and indicate that emissions from ground and stem compartments essentially contribute to the canopy VOC flux. Overall the results open new perspectives to explore chirality as a possible marker to recognize shifts in the contributions of different VOC sources present within forest ecosystems and to explain observed temporal changes in the chiral signature of pinenes in the atmosphere.

Essential oil composition of aerial parts from Algerian Anacyclus monanthos subsp. cyrtolepidioides (Pomel) Humphries.

The chemical composition of the essential oil from the aerial parts of Anacyclus monanthos subsp. cyrtolepidioides (Pomel) Humphries (Asteraceae) growing in a semi-arid region of Algeria was investigated for the first time. The essential oil was obtained by hydrodistillation and fully characterized by gas chromatography-mass spectrometry (GC-MS). A total of 97 compounds were identified. The essential oil was found to be rich in trans-chrysanthenyl acetate (9.8 ± 2.0%), (E)-ß-farnesene (7.4 ± 1.5%), germacrene D (6.9 ± 1.3%) and myristicin (4.8 ± 0.8%).

Chemical composition and antioxidant activities of essential oil of Hedychium greenii and Hedychium gracile from India.

The chemical constituents of the essential oils hydrodistilled from rhizome parts of Hedychium greenii W.W. Sm. and Hedychium gracile Roxb, of family Zingiberaceae, growing in India, were analysed for the first time by GC-FID and GC-MS, respectively. A total of 30 and 29 components representing 99.62 and 96.74% of the total oil were identified in the essential oils of H. greenii and H. gracile, respectively. The major components of H. greenii were bornyl acetate (31.32%), α-pinene (14.49%), camphene (12.81%) and limonene (10.55%), whereas H. gracile was dominated by ß-pinene (25.24%), γ-terpinene (24.62%), terpinen-4-ol (14.87%) and 1,8-cineole (7.51%). Essential oils were assessed for antioxidant potential using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay. H. greenii oil exhibited stronger antioxidant potential as compared to H. gracile oil and butylated hydroxytoluene (BHT). Thus, H. greenii rhizome oil has the potential to be used as an alternative source of antioxidant.

Variation in essential oil composition of Teucrium hircanicum L. from Iran-A rich source of (E)-α-bergamotene.

In present work, the chemical composition of the essential oils obtained from dried flowering aerial parts of Teucrium hircanicum L. (Labiatae) originated from ten wild populations in Iran was analyzed by a GC-FID and GC/MS system. The oil yields varied from 0.04% to 0.1%. A total of thirty-two compounds representing 67.6-97.7% of the oil were identified. The essential oil was found to be rich in sesquiterpene hydrocarpons (E)-α-bergamotene (17.5-86.9%) and (E)-ß-farnesene (0.5-21.4%). Of the total identified compounds, sesquiterpene hydrocarpons (36.1-89.7%) were included the greatest essential oil fraction in all the populations, followed by oxygenated monoterpenes (2.2-21.6%), oxygenated sesquiterpenes (0.0-14.4%) and monoterepene hydrocarbons (0.0-9.5%). Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used to distinguish any geographical variations, indicating that the clustering of populations is related to their geographic origin. According to the GC/MS analysis, two chemotypes consisting of (E)-α-bergamotene and (E)-α-bergamotene-(E)-ß-farnesene were identified in the populations.

Piper nigrum Oil - Determination of Selected Terpenes for Quality Evaluation.

The growing demand and commercial value of black pepper (Piper nigrum) has resulted in considerable interest in developing suitable and cost-effective methods for chemical characterization and quality evaluation purposes. In the current study, an extensive set of oil samples (n = 23) that were extracted by steam distillation from black pepper seeds was investigated to compare the chemical profiles of samples originating from nine major producing countries, as well as to identify potential chemical markers for quality evaluation. The twenty-two most abundant volatile compounds, mainly terpenes, in these oils were determined by conventional GC/MS analysis. Principal component analysis with this set of data revealed distinct clusters for samples that originated from China and Malaysia. Relatively low concentrations of sabinene (< 0.2%) and high concentrations of 3-carene (10.9 - 21.1%) were observed in these samples, respectively, compared to oil samples from other countries. The enantiomeric distributions of key terpene markers, viz., ß-pinene, sabinene, limonene, and terpinen-4-ol, were determined by chiral GC/MS analysis. Interestingly, for these four monoterpenes, levo-isomers were found to be predominant, emphasizing the highly conserved enzymatic processes occurring in P. nigrum. Moreover, consistent enantiomeric ratios ((-) isomer/(+) isomer) of 92.2 ± 3.0% for ß-pinene, 94.8 ± 2.8% for sabinene, 60.7 ± 1.1% for limonene, and 78.3 ± 1.3% for terpinen-4-ol were observed, independent of geographical location. These results demonstrate the potential of using stereospecific compositions as chiral signatures for establishing the authenticity and quality of black pepper oil.

Schinus molle essential oil as a potential source of bioactive compounds: antifungal and antibacterial properties.

AIMS: The study was focused on the evaluation of antimicrobial activity in vitro of the essential oil (EO) of leaves from Schinus molle against bacteria and fungi of clinical importance in the search for the discovery of new active compounds. METHODS AND RESULTS: The chemical composition of the S. molle EO was determined by gas chromatography/mass spectrometry and its antimicrobial effect was verified by broth microdilution method. The major compounds found were ß-pinene (25·23%), epi-α-cadinol (21·29%), α-pinene (18·72%), myrcene (11·54%) and sabinene (5·02%). The EO showed significant antifungal activity against Paracoccidioides brasiliensis (39·06 µg ml-1 ), weak action against Cryptococcus neoformans (625 µg ml-1 ) and Trichophyton quinckeanum (625 µg ml-1 ) and was inactive against Candida sp. In the analysis of the antibacterial action, the micro-organisms tested did not show sensitivity. CONCLUSIONS: This study showed a promising result of S. molle volatiles against the fungus P. brasiliensis, which causes paracoccidioidomycosis (PCM), a systemic mycosis of great clinical importance in Latin America. SIGNIFICANCE AND IMPACT OF THE STUDY: The results found here are novel and encourage investigations of the compounds present in this EO, which represents a source of molecules with potential use in the treatment of PCM.

Chemical composition of essential oils of Anthemis secundiramea Biv. subsp. secundiramea (Asteraceae) collected wild in Sicily and their activity on micro-organisms affecting historical art craft.

In the present study, the chemical composition of the essential oil from the aerial parts of Anthemis secundiramea Biv. subsp. secundiramea L. collected in Sicily was evaluated by GC and gas chromatography-mass spectrometry. The main components of A. secundiramea were (Z)-lyratyl acetate (14.6%), (Z)-chrysanthenyl acetate (9.9%), (Z)-chrysanthenol (8.7%) and (E)-chrysanthenyl acetate (7.7%). The comparing with other studied oils of genus Anthemis belonging to the same clade is discussed. Antibacterial and antifungal activities against some micro-organisms infesting historical art craft, were also determined.

Simultaneous determination of iprodione, procymidone, and chlorflurenol in lake water and wastewater matrices by GC-MS after multivariate optimization of binary dispersive liquid-liquid microextraction.

This study reports the optimization of a binary dispersive liquid-liquid microextraction method for the determination of iprodione, procymidone, and chlorflurenol by gas chromatography mass spectrometry. The study was aimed at using two extraction solvents to increase the extraction efficiency of all analytes. The binary solvents recorded results higher than the mono-solvents. After examining the effects of main experimental parameters and their interactions by analysis of variance, 200 µL of binary mixture (dichloromethane and 1,2-dichloroethane), 2.5 mL of ethanol, and 15 s vortex were obtained as optimum parameters. The detection and quantification limits calculated for the analytes were found to be between 0.30-1.6 and 1.0-5.3 ng/mL, respectively. Enhancement in detection power calculated as a ratio of the binary extraction detection limit to the detection limit of direct GC-MS analysis was 105-, 214-, and 233-fold for chlorflurenol, iprodione, and procymidone, respectively. In order to check the accuracy of the developed method, recovery study was performed. Water sampled from a lake and two wastewater samples from treatment facilities were spiked at two concentrations, and the percent recovery calculated for the samples ranged between 87 and 116%. These results confirmed the suitability of the method to real samples for accurate determination of the analytes at trace levels.

Morphophysiological and Phytochemical Variability in Some Wild Populations of Ducrosia anethifolia from Iran.

In order to determine the morphophysiological and phytochemical properties of various Ducrosia anethifolia populations, the plant samples were collected from 20 locations in native regions. Current study indicated significant differences in the morphophysiological and phytochemical characteristics of D. anethifolia populations collected from 20 locations in Sistan and Baluchestan Province, Iran. The highest value of plant height and the number of lateral stems, node per plant, umbellate per umbel, seeds per umbellate and the roots fresh and dry weight were related to the location with relatively high rainfall (130-161 mm) and low altitude (up to 1165 m) compared with others. Based on the essential oil components, D. anethifolia populations were divided into five different chemotypes. Chemotypes I, II and III were characterized by high amounts of methyl chavicol, chrysanthenyl acetate and decanal, respectively. Moreover, the populations with high amounts of decanal, anethole and dodecanal were placed in chemotype IV. Chemotype V was attributed to the Naserabad population with 1-decanol as the major compound.

Oviposition deterrent activity of basil plants and their essentials oils against Tuta absoluta (Lepidoptera: Gelechiidae).

The leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yields by up to 100% in greenhouses and fields, in several countries globally. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and the health of producers, alternative control methods are needed. In this study, we assessed the oviposition-deterring effect of basil plants, Ocimum gratissimum L. and O. basilicum L. (Lamiaceae), using dual-choice behavioural assays performed in flight tunnels. We found that both plants significantly reduced T. absoluta oviposition behaviour on a tomato plant located nearby. To evaluate the potential effect of basil volatile organic compounds, we formulated essential oils of both plant species in paraffin oil, and observed a similar oviposition-deterring effect. Gas chromatography analyses detected 18 constituents in these essential oils which the major constituents included thymol (33.3%), p-cymene (20.4%), γ-terpinene (16.9%), myrcene (3.9%) in O. gratissimum and estragol (73.8%), linalool (8.6%), ß-elemene (2.9%) and E-ß-ocimene (2.6%) in O. basilicum. Twenty and 33 compounds were identified of the volatiles collected on O. gratissimum and O. basilicum plants, respectively. The main components include the following: p-cymene (33.5%), γ-terpinene (23.6%), α-terpinene (7.2%), α-thujene (6.7%) and E-α-bergamotene (38.9%) in O. gratissimum, and methyl eugenol (26.1%), E-ß-ocimene (17.7%), and linalool (9.4%) in O. basilicum. Four compounds (α-pinene, ß-pinene, Myrcene, Limonene) were common in essential oils and plants. Our results suggest the valuable potential of basil and associated essential oils as a component of integrated management strategies against the tomato leafminer.

Essential oils Constituents of the leaves of Amomum gagnepainii and Amomum repoense.

The chemical constituents identified in the essential oils hydrodistilled from the leaves of Amomum gagnepainii T.L.Wu, K.Larsen and Turland and Amomum repoense Pierre ex Gagnep (Zingiberaceae) of Vietnam origin are reported. The chemical analyses were performed by means of gas chromatography-flame ionisation detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). The main compounds of A. gagnepainii were farnesyl acetate (18.5%), zerumbone (16.4%) and ß-caryophyllene (10.5%). On the other hand, Amomum repoense comprised of monoterpenes dominated by ß-pinene (33.5%), (E)-ß-ocimene (9.6%), γ-terpinene (9.1%) and α-pinene (8.4%). This is the first report on the essential oils of A. gagnepainii and A. repoense grown in Vietnam or elsewhere.

Attraction behaviour of Anagrus nilaparvatae to remote lemongrass (Cymbopogon distans) oil and its volatile compounds.

Utilisation of Anagrus nilaparvatae is a promising and effective method for planthoppers manipulation. Twenty-seven components of remote lemongrass (Cymbopogon distans) oil were identified by GC/MS and nine volatiles were selected for behavioural experiments. In this study, we noted that the remote lemongrass oil was attractive to female A. nilaparvatae at concentrations of 0.1 and 1 mg/L. α-Pinene, ß-pinene, eucalyptol, carveol and D-carvone attracted female wasps in the dose-dependent bioassays. Blend 1 (a mixture of eucalyptol, D-carvone, carveol, α-pinene, and ß-pinene with ratios of remote lemongrass oil volatiles of 625:80:11:5:3) attracted female wasps at 10 mg/L, while blend 2 (a mixture of the same five volatiles at the same loading ratio) attracted them at 0.1 and 1 mg/L. These results suggested that plant essential oils could be attractants for natural enemies to control pests. The ratios of volatiles in the mixtures affect the attractiveness of the synthetic mixtures.

Jasmonic acid changes the composition of essential oil isolated from narrow-leaved lavender propagated in in vitro cultures.

The aim of the present study was to determine the effect of jasmonic acid added to the culture medium on composition of Lavandula angustifolia essential oils. The chemical composition was determined by gas chromatography coupled to mass detector (GC/MS). The experiment was conducted with the use of MS medium supplemented with increasing concentration of JA (0.2, 0.5, 1, 1.5 mg∙dm-3). It was found that the analysed essential oils varied in terms of chemical composition depending on the content of JA in the medium. All obtained essential oils were characterised by a high content of σ-cadinene (17.06-29.64%), borneol (6.66-17.47%), caryophyllene oxide (8.30-14.01%), τ-cadinol (4.87-9.16%), beta-caryophyllene (3.54-6.57%), 1.8-cineole (1.94-5.87%), ß-pinene (1.48-3.05%), geranyl acetate (0.56-2.14%) and myrtenal (0.65-2.14%).

New particle formation and growth at a suburban site and a background site in Hong Kong.

Atmospheric nanoparticles have great impacts on human health and global climate change. The number concentrations and size distributions of nanoparticles in the size range of 5.5-350.4 nm were detected at a background site and a suburban site in Hong Kong from summer to winter in 2011 and in autumn of 2013, respectively. Significantly higher particle number concentrations in all modes were observed at the suburban site (p < 0.05) during the sampling periods, possibly due to stronger primary emissions/regional transport and more intensive new particle formation (NPF). Particle number concentrations were much enhanced under northerly winds at both sites, resulting from regional transport of Aitken and accumulation mode particles, enhanced local NPF and occasionally low condensation sink. NPF was mainly limited by the precursors of condensable vapors and oxidative capacity of the atmosphere at the background site and the suburban site, respectively. In most cases, the formation rate of 5.5 nm particles was a function of sulfuric acid vapor to the power of 1.32 ± 0.34 at the background site and 0.81 ± 0.31 at the suburban site, abiding by the cluster activation theory. However, ozonolysis of monoterpenes (particularly α-pinene) might also drive NPF, particularly in the afternoon. These reactions also contributed to the growth of nucleation mode particles, which was largely explained by sulfuric acid vapor (73.6 ± 10% at the background site and 60.4 ± 9.8% at the suburban site). In contrast, the oxidations of isoprene, ß-pinene and aromatics (particularly xylenes and trimethylbenzenes) were found to participate in the growth of Aitken mode particles.