(-)-alpha-Pinene

Influence of physiological and environmental factors on the diurnal variation in emissions of biogenic volatile compounds from Pinus tabuliformis.[Pubmed:30975314]

J Environ Sci (China). 2019 Jul;81:102-118.

Biological volatile organic compounds (BVOCs) have a large influence on atmospheric environmental quality, climate change and the carbon cycle. This study assesses the composition and diurnal variation in emission rates of BVOCs from Pinus tabuliformis, using an enclosure technique. Environmental parameters (temperature and light intensity) and physiological parameters (net photosynthetic rate, Pn; stomatal conductance, gs; intercellular CO2 concentration, Ci; and transpiration rate, Tr) that may affect emission behavior were continuously monitored. The 10 most abundant compound groups emitted by P. tabuliformis were classified by gas chromatography-mass spectrometry. The dominant monoterpenoid compounds emitted were alpha-pinene, beta-myrcene, alpha-farnesene and limonene. The diurnal emission rate of BVOCs changed with temperature and light intensity, with dynamic analysis of BVOCs emissions revealing that their emission rates were more affected by temperature than light. The variation in monoterpene emission rates was consistent with estimates of Pn, gs and Tr. Basal emission rates (at 30 degrees C,) of the main BVOCs ranged from 0.006 to 0.273mug(-1)/(hr g), while the basal ER standardization coefficients ranged from 0.049 to 0.144 degrees C(-1). Overall, these results provide a detailed reference for the effective selection and configuration of tree species to effectively prevent and control atmospheric pollution.

Chemodiversity of Essential Oils in Seseli libanotis (L.) W.D.J.Koch (Apiaceae) in Central Europe.[Pubmed:30969463]

Chem Biodivers. 2019 Apr 10.

Seseli libanotis is an aromatic umbelliferous plant distributed sporadically on dry grassland egdes in Europe and Western Asia. The essential oil composition in the different plant parts was studied from plants collected on 9 sites in Austria and one site in Alto Adige, Italy. Monoterpenes as alpha-pinene, sabinene and beta-myrcene and the sesquiterpene germacrene D were present in all essential oils from the aerial parts. Inflorescences and fruits had the highest essential oil contents. These essential oils from four sites were rich in acorenone B, while from other three sites they had carotol as a major component. Osthole as furocoumarin occurred in some oils. The root essential oils were dominated by alpha-pinene. The essential oil variability has been studied by principal component analysis (PCA) and discriminant analysis (DA) with plant parts or sampling site as a priori groups. PCA could well separate Inflorescence inflorescence and fruit essential oil samples from leaf and stem essential oil samples. DA differentiated well between the plant parts and most of the sampling sites.

Promising insecticidal efficacy of the essential oils from the halophyte Echinophora spinosa (Apiaceae) growing in Corsica Island, France.[Pubmed:30963429]

Environ Sci Pollut Res Int. 2019 Apr 8. pii: 10.1007/s11356-019-04980-y.

Echinophora spinosa (Apiaceae) is a psammophilous species growing along Mediterranean coastal sand dunes. This species secretes essential oils made up of monoterpenoids, phenylpropanoids, and polyacetylenes, which may represent effective, eco-friendly and safe active ingredients for the preparation of green insecticides. Based on this, in the present study, we selected a French accession of E. spinosa growing on the coastal dunes of Corsica, extracting the essential oils from aerial parts and roots by hydrodistillation. The essential oils were analyzed by GC-MS for chemical composition and screened for their insecticidal activity on three target insects, Culex quinquefasciatus, Spodoptera littoralis, and Musca domestica. The essential oil from roots was dominated by the phenylpropanoid myristicin and the monoterpene hydrocarbon terpinolene, with a minor contribution of (Z)-falcarinol. The oil from the aerial parts was characterized by monoterpenes, mainly p-cymene, a-phellandrene, and alpha-pinene. The root essential oil exhibited promising toxicity on the target insects, with special reference to C. quinquefasciatus larvae (LC50 = 15.7 mg L(-1)), while on M. domestica and S. littoralis, it showed LD50 of 38.3 mug adult(-1) and 55.6 mug larva(-1), respectively. Based on our findings, E. spinosa can be viewed as a new potential crop to produce insecticidal essential oils in arid salty areas. However, synergistic and antagonistic effects of the major constituents of both oils tested here deserve future research. Further studies on the efficacy of stable formulations of the E. spinosa root essential oil, with special reference to micro- and nanoformulations, are ongoing.

Effect of simultaneous snail slime-aided degradation and yeast fermentation on terpenoid composition of plantain pseudostem waste.[Pubmed:30961480]

Curr Pharm Biotechnol. 2019 Apr 8. pii: CPB-EPUB-97888.

BACKGROUND: In this study, local sustainable enzyme sources involving excised digestive juice of African land snail and yeast were to achieve the simultaneous saccharification and fermentation (SSF) of plantain pseudo stem (PPS) waste, and afterwards examined their effects on terpenoids using gas chromatograpy coupled to a fluorescent ionization detector (GC-FID). RESULTS: The most abundant terpenoids were found in the order alpha-pinene > borneol > camphor > humulene > beta-caryophellene, while the least in abundance were cis ocimene (8.78x10-6 mg/100g), and cyperene (1.81x10-5 mg/100g). The application of exclusive fermentation, and SSF respectively elevated azuluene by 95.46 and 99.6 %, while pinene-2-ol was elevated by 83.02 and 98.57 % respectively. Both exclusive fermentation and SSF had no effect on myrcene, cyperene, ethyl cinnamate, germacrene b, valencene, beta selinene, aromadendrene, and taraxerol, while the degree of degradation of some of the terpenoids by both processes were respectively as follows; gama muurolene (100%), beta-caryophyllene (97.60 and 93.14 %), alpha-terpinenyl acetate (91.95 and 83.16 %), geranyl acetate (94.81 and 43.87 %), and terpinen-4-ol (94.40 and 57.00 %). CONCLUSION: The findings of this study indicate the imminent application of simultaneous saccharification and fermentation for the enhancement of bioactivities of terpenoids.

Using Ionic Liquids to Study the Migration of Semi-Volatile Organic Vapors in Smog Chamber Experiments.[Pubmed:30950612]

J Phys Chem A. 2019 Apr 5.

Atmospheric organic aerosols comprise complex mixtures of myriad compounds with a wide range of structures and volatility. To understand the fate of atmospheric organic aerosols and their contribution to particulate matter pollution, we need to study the relative portion divided between semi-volatile organic compounds (SVOCs) and low-volatility organic compounds (LVOCs). SVOCs can effectively migrate and exchange between aerosol populations and thus are more accessible for further reactions and removal processes while LVOCs will essentially stay in the particle phase. Here we introduce using ionic-liquid droplets as novel sorbents for organic vapors in smog-chamber experiments to study the transfer of constituents between aerosol populations and to separate SVOCs and LVOCs from chamber-produced secondary organic aerosols (SOA). SOA was formed and condensed on the ammonium-sulfate seeds and later ionic-liquid droplets were introduced into the chamber. We show that there is a considerable yield of both LVOCs and SVOCs produced from alpha-pinene ozonolysis and the uptake of SVOCs into the ionic liquid increases as the amount of reacted alpha-pinene increase. We also show that the SVOCs absorbed into the ionic liquid re-evaporate more readily compared to SOA originally condensed on the ammonium-sulfate seeds. We are thus able to differentiate the semi-volatile components that partition into the extremely polar ionic liquid aerosols from the demonstrably less volatile components also condensed on the ammonium-sulfate seeds. Combining with previous studies using other organic aerosols as solvents to probe SVOCs transfer between aerosol populations, we provide a wide set of measurements to probe and constrain the physical and thermodynamic properties of chamber-produced SOA complex.

Antimicrobial Activity and Chemical Composition of Essential Oil Extracted from Solidago canadensis L. Growing Wild in Slovakia.[Pubmed:30934783]

Molecules. 2019 Mar 27;24(7). pii: molecules24071206.

Plant essential oils (EOs) are one of the most relevant natural products due to their biological, medicinal, and nutritional properties. The promising biological effects of many plants EOs encourage researchers to study their biochemical properties to be used as possible natural alternatives for commercial pesticides and not only as herbal medicines. The current research has been conducted to study the microbicide effect of Solidago canadensis L. EO to control some common plant diseases caused by several postharvest phytopathogenic fungi (Monilinia fructicola, Botrytis cinerea, Aspergillus niger, and Penicillium expansum) in comparison with Azoxystrobin as a large spectrum fungicide. The antibacterial activity has been carried out against some phytopathogenic bacteria (Bacillus megaterium and Clavibacter michiganensis (G+ve) and Xanthomonas campestris, Pseudomonas fluorescens, and Pseudomonas syringae pv. phaseolicola (G-ve)) compared to the synthetic antibiotic Tetracycline. Minimum inhibitory concentration was carried out to determine the lowest effective EO dose using a 96-well microplate. The cell membrane permeability was also evaluated by measuring the electric conductivity (EC) to examine the possible mechanisms of action of S. canadensis EO. Chemical characterization of EO has been carried out using gas chromatography and mass spectrometry (GC-MS). Thirty-two identified components in S. canadensis EO presented 97.7% of total compounds in EO. The principal compounds were identified as germacrene D (34.9%), limonene (12.5%), alpha-pinene (11.6%), beta-elemene (7.1%), and bornyl acetate (6.3%). In addition, S. canadensis EO demonstrated promising in vitro antimicrobial activities against the majority of tested phytopathogens at all tested concentrations.

Influence of Particle Surface Area Concentration on the Production of Organic Particulate Matter in a Continuously Mixed Flow Reactor.[Pubmed:30924647]

Environ Sci Technol. 2019 Apr 12.

Organic particulate matter (PM) was produced at different particle surface area concentrations S in a continuously mixed flow reactor (CMFR). The apparent PM yield from the dark ozonolysis of alpha-pinene increased from 24.5 +/- 0.7% to 57.1 +/- 0.6% for an increase in S from 0.55 to 2.87 x 10(3) mum(2).surface cm(-3).volume. The apparent yield saturated for S > 2.1 x 10(3) mum(2) cm(-3). There was hysteresis in the apparent yield for experiments of increasing compared to decreasing S. The relative timescales of gas-particle interactions, gas-wall interactions, and thereby particle-wall cross interactions could explain the results. The PM carbon oxidation state and oxygen-to-carbon atomic ratio decreased from -0.19 to -0.47 and 0.62 to 0.51, respectively, for increasing S, suggesting that greater partitioning of semivolatile organic species into the PM contributed to the increased PM yield. A thorough understanding of the role of gas-wall interactions on apparent PM yield is essential for the extension of laboratory results into predictions of atmospheric PM production, and comparative results from CMFRs and batch reactors can be informative in this regard.

Controlled Release of Peppermint Oil from Paraffin-Coated Activated Carbon Contained in Sachets to Inhibit Mold Growth During Long Term Storage of Brown Rice.[Pubmed:30912858]

J Food Sci. 2019 Apr;84(4):832-841.

The aim of the study was to control the release of peppermint oil (700 microL/L) by coating activated carbon (AC) contained in sachets with different solutions (tapioca starch, corn starch, gelatine, carnauba, paraffin, and mixed carnauba-paraffin) for inhibiting the growth of Aspergillus flavus on brown rice (BR). Paraffin-coated AC with adsorbed peppermint oil was then applied to extend the shelf life of BR during long-term storage (60 days) at 30 +/- 2 degrees C. The mechanism of peppermint oil vapor release in this system was also studied using GC-MS. The result revealed that paraffin-coated AC with adsorbed peppermint oil present in sachets showed the highest antifungal activity against A. flavus growing on the surface of BR. In addition, paraffin-coated AC with adsorbed peppermint oil could prolong the shelf life of BR from 10 days (control) to at least 60 days under tropical climatic conditions. Moreover, storage of BR in the presence of sachets containing paraffin-coated AC with adsorbed peppermint oil at a concentration of 700 microL/L revealed no significant effects on major rice quality-related factors, such as moisture content, color, water uptake percentage, and gelatinization temperature. Peppermint oil component analysis by GC-MS indicated that paraffin could trap some minor components of peppermint oil and allow the major components such as menthone, menthol, and alpha-pinene, which are compounds that play an important role in mold growth inhibition, to be exposed to air. Thus, this research demonstrated the potential of paraffin-coated AC containing adsorbed peppermint oil for controlling the growth of molds during prolonged rice storage. PRACTICAL APPLICATION: Paraffin-coated activated carbon with adsorbed peppermint oil has the potential to be commercially applied to brown rice grains for facilitating long-term storage. This technique is beneficial for avoiding the occurrence of negative sensorial factors when peppermint oil vapors are used. This process is interesting and easy to apply during large-scale implementation of a rice storage system.

Chemical composition, antioxidant, antimicrobial and anticancer activities of the essential oil from the rhizomes of Zingiber striolatum Diels.[Pubmed:30908095]

Nat Prod Res. 2019 Mar 25:1-5.

The chemical composition and biological activities of the essential oil (EO) from the rhizomes of Zingiber striolatum Diels were reported for the first time. Forty-five compounds were identified, and represented 95.7% of the total composition of the EO. The predominant components of the EO were beta-phellandrene (24.0%), sabinene (17.3%), beta-pinene (11.4%), geranyl linalool (8.6%), terpinen-4-ol (8.3%), alpha-pinene (5.6%) and crypton (4.5%). The EO revealed a weak DPPH and ABTS radical-scavenging activity. The EO exhibited significant antimicrobial activity with the inhibition zones (12.86-24.62 mm) and MIC (0.78-3.12 mg/mL) against Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans. The EO showed significant cytotoxicity against human leukemic (K562), lung cancer (A549) and prostatic carcinoma (PC-3) cell lines with the IC50 values of 29.67, 48.87 and 86.05 mug/mL, respectively. Thus, the EO could be regarded as a bioactive natural product with potential for utilization in the cosmetic and pharmaceutical industry.

Influence of Monoterpenes in Biological Activities of Nectandra megapotamica (Spreng.) Mez Essential Oils.[Pubmed:30901829]

Biomolecules. 2019 Mar 21;9(3). pii: biom9030112.

Investigating the influence of seasonal variations on biological activities is important for pharmacological studies and metabolic engineering. Therefore, this study was conducted to determine the variation of the chemical composition of essential oils obtained from Nectandra megapotamica leaves, collected at different stages of plant development, as well as its influence on the biological activities. A total of 38 compounds were identified that accounted for 97(-)99.2% of the chemical composition of the oils. Major differences were observed in the monoterpenic fraction, representing 5.1% of the compounds identified in the productive rest phase to 37.1% in the blooming phase. Bicyclogermacrene and germacrene D were the predominant compounds identified in the oil of all collections. Furthermore, limonene, beta-pinene, and spathulenol were identified predominantly in the samples of blooming and fruiting phases. The oils exhibited significant antichemotactic activity and different effects in scavenging the radical 2,2-diphenyl-1-picrylhydrazyl. Variations were also observed in the antifungal activity, with the minimum inhibitory concentrations ranging from 125 to 500 mug/mL. These results demonstrate the influence of monoterpenes, primarily limonene, alpha-pinene, and beta-pinene, on the bioactivities of the oil. Studies investigating the variations in the chemical composition of essential oil may offer a strategy to produce a compound or a group of compounds of interest to industries with a specific pharmacological focus.

Comparison of the oxidative potential of primary (POA) and secondary (SOA) organic aerosols derived from alpha-pinene and gasoline engine exhaust precursors.[Pubmed:30828421]

F1000Res. 2018 Jul 9;7:1031.

Background: Primary (POA) and secondary (SOA) organic aerosols, deriving from both anthropogenic and biogenic sources, represent a major fraction of ambient particulate matter (PM) and play an important role in the etiology of respiratory and cardiovascular diseases, largely through systemic inflammation and cellular oxidative stress. The relative contributions of these species to the inhalation burden, however, are rather poorly characterized. In this study, we measured the in vitro oxidative stress response of alveolar macrophages exposed to primary and secondary PM derived from both anthropogenic and biogenic sources. Methods: POA and SOA were generated within an oxidation flow reactor (OFR) fed by pure, aerosolized alpha-pinene or gasoline engine exhaust, as representative emissions of biogenic and anthropogenic sources, respectively. The OFR utilized an ultraviolet (UV) lamp to achieve an equivalent atmospheric aging process of several days. Results: Anthropogenic SOA produced the greatest oxidative response (1900 +/- 255 microg-Zymosan/mg-PM), followed by biogenic (alpha-pinene) SOA (1321 +/- 542 microg-Zymosan/mg-PM), while anthropogenic POA produced the smallest response (51.4 +/- 64.3 microg-Zymosan/mg-PM). Conclusions: These findings emphasize the importance of monitoring and controlling anthropogenic emissions in the urban atmosphere, while also taking into consideration spatial and seasonal differences in SOA composition. Local concentrations of biogenic and anthropogenic species contributing to the oxidative potential of ambient PM may vary widely, depending on the given region and time of year, due to factors such as surrounding vegetation, proximity to urban areas, and hours of daylight.

New Bio-Polyamides from Terpenes: alpha-Pinene and (+)-3-Carene as Valuable Resources for Lactam Production.[Pubmed:30892749]

Macromol Rapid Commun. 2019 Mar 20:e1800903.

The synthesis and polymerization of two beta-lactams and two epsilon-lactams derived from the terpenes alpha-pinene and (+)-3-carene are reported. The new biopolymers can be considered as polyamide 2 (PA2) and polyamide 6 (PA6)-types with aliphatic stereoregular side chains, which lead to remarkable new properties. The macromolecules are investigated by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and infrared (IR). The (+)-3-carene-derived PA6-type is of particular interest, since it reaches a molecular weight of over 30 kDa, which is the highest value for lactam-based polyamides derived from terpenes reported to date. Additionally, a glass transition temperature (Tg ) of 120 degrees C is observed, surpassing the glass transition temperature of PA6 by 60 degrees C. The absence of a melting point (Tm ) indicates high amorphicity, another novelty for terpene-based polyamides, which might give transparent bio-polyamides access to new fields of application.

Chemical characterization of Euphorbia heterophylla L. essential oils and their antioxidant activity and allelopathic potential on Cenchrus echinatus L.[Pubmed:30875445]

Chem Biodivers. 2019 Mar 15.

The genus Euphorbia attracted the attention of many researchers worldwide, from natural products, bioactivity, and ecological perspective. The essential oils (EOs) of Euphorbia heterophylla are poorly studied. Therefore the present study aimed to provide a detailed profile of the E. heterophylla EOs as well as determine thier antioxidant and allelopathic activities. The EOs from aerial parts of E. heterophylla were extracted using hydrodistillation and analyzed via GC-MS. The antioxidant activity was determined based on scavenging of the free radicle, 1,1-Diphenyl-2-picrylhydrazyl and H2O2. Various concentrations of the EOs were tested against the noxious weed, Cenchrus echinatus. Thirty-five compounds were identified representing 100% of the total mass. Four classes of components were characterized among which terpenoids were the main components (88.70%). Monoterpenes represented the main class (69.48%), followed by sesquiterpenes (18.63%), and only one diterpenoid, kaur-16-ene, was identified. The 1,8-cineole (32.03%), camphor (16.54%), beta-elemene (5.92%), endo-borneol (4.94%), limonene (4.27%), n-pentatriacontane (3.91%), alpha-pinene (3.89%) were the major compounds. The EOs composition of Egyptian E. heterophylla ecospecies was comparable to other reported Euphorbia species, although it showed no correlation with Nigerian E. heterophylla ecospecies. The EOs from E. heterophylla aerial parts exhibited significant antioxidant activity. Moreover, a concentration of 100 microL L-1 of the EOs reduced the germination, root, and shoot growth of C. echinatus by about 93.95%, 84.6%, and 57.8%, respectively. Therefore, the EOs from E. heterophylla could be integrated into the control of this weed, as eco-friendly biocontrol method. Further study is needed to characterize their allelopathic activity at field conditions as well as to evaluate their durability and biosafety.

The molecular and cellular basis of olfactory response to tsetse fly attractants.[Pubmed:30875383]

PLoS Genet. 2019 Mar 15;15(3):e1008005.

Dipteran or "true" flies occupy nearly every terrestrial habitat, and have evolved to feed upon a wide variety of sources including fruit, pollen, decomposing animal matter, and even vertebrate blood. Here we analyze the molecular, genetic and cellular basis of odor response in the tsetse fly Glossina morsitans, which feeds on the blood of humans and their livestock, and is a vector of deadly trypanosomes. The G. morsitans antenna contains specialized subtypes of sensilla, some of which line a sensory pit not found in the fruit fly Drosophila. We characterize distinct patterns of G. morsitans Odor receptor (GmmOr) gene expression in the antenna. We devise a new version of the "empty neuron" heterologous expression system, and use it to functionally express several GmmOrs in a mutant olfactory receptor neuron (ORN) of Drosophila. GmmOr35 responds to 1-hexen-3-ol, an odorant found in human emanations, and also alpha-pinene, a compound produced by malarial parasites. Another receptor, GmmOr9, which is expressed in the sensory pit, responds to acetone, 2-butanone and 2-propanol. We confirm by electrophysiological recording that neurons of the sensory pit respond to these odorants. Acetone and 2-butanone are strong attractants long used in the field to trap tsetse. We find that 2-propanol is also an attractant for both G. morsitans and the related species G. fuscipes, a major vector of African sleeping sickness. The results identify 2-propanol as a candidate for an environmentally friendly and practical tsetse attractant. Taken together, this work characterizes the olfactory system of a highly distinct kind of fly, and it provides an approach to identifying new agents for controlling the fly and the devastating diseases that it carries.

Hydrodistillation Extraction Kinetics Regression Models for Essential Oil Yield and Composition in Juniperus virginiana, J. excelsa, and J. sabina.[Pubmed:30862073]

Molecules. 2019 Mar 11;24(5). pii: molecules24050986.

The chemical profile and antioxidant capacity of Juniperus virginiana, J. excelsa, and J. sabina essential oil (EO) fractions as a function of time was the subject of this study. The hypothesis was that, capturing EO in sequential timeframes during hydrodistillation would generate fractions containing unique compositions and antioxidant capacity. In J. virginiana, the highest limonene (43%) was found in the 0(-)5 min oil fraction, with safrole (37%) being highest in the 10(-)20 and 20(-)40 min fractions, and elemol (34%) being highest in the 160(-)240 min fraction. In J. excelsa, alpha-pinene (34-36%) was the highest in the 0(-)5 min fraction and in the control (non-stop 0(-)240 min distillation) oil, limonene (39%) was the highest in the 0(-)10 min fractions and cedrol (50-53%) was the highest in the 40(-)240 min fractions. In J. sabina, sabinene (80%) was highest in the 0(-)3 min fraction. The highest antioxidant capacity of J. virginiana was demonstrated by the 5(-)10 min fraction; the one in J. sabina by the 3(-)10 min fraction; and, the one in J. excelsa, by the control. The kinetics regression models that were developed can predict EO composition of the three juniper species eluted at different timeframes. Various industries could benefit from the results from this study.