Search

Dendritic ZSM-5 zeolites were investigated in the isomerization of monoterpene epoxides, including limonene-1,2-epoxide (LE), α-pinene epoxide, and β-pinene epoxide, which yields high-value compounds used in fragrances, cosmetics, and pharmaceuticals. The fresh catalysts were thoroughly characterized using XRD, Ar physisorption, pyridine-FTIR, TEM, FTIR/DTBPyr, and 27Al MAS NMR. In comparison with conventional and hierarchical ZSM-5 materials, the dendritic zeolite with a crystallization time of 4 days (d-ZSM-5/4d) was the most active material, with a turnover frequency value of 4.4 min−1 for LE isomerization. Likewise, remarkable yields of dihydrocarvone (DHC, 63%, 70 °C, 2 h), campholenic aldehyde (72.4%, 70 °C, 5 min), and myrtanal (47.7%, 50 °C, 5 min) were obtained with this material that exhibited the largest mesopore/external surface area (360 m2 g−1), showing also the narrowest mesopore size distribution. A direct relationship was observed between the TOF values and the concentration of external Brønsted acid sites, showing the presence of strong steric/diffusional limitations that are greatly overcome with the dendritic zeolites. The lower reactivity of trans-LE compared to cis-LE was attributed to the larger steric hindrance of the oxygen atom. Exploration of the solvent influence revealed that the reaction rate of LE was favored by non-polar solvents, while highly selective DHC formation occurred in the solvents of medium polarity. The d-ZSM-5/4d sample was shown to be robust because catalytic activity could be completely recovered by air calcination. [ABSTRACT FROM AUTHOR]

The root of Paeonia lactiflora pall. is a significant component of traditional Chinese medicine, with terpenoids and their glycosides, such as paeoniflorins, serving as key active ingredients known for their anti-inflammatory, hepatoprotective, and analgesic properties. By generating a transcriptome and functionally characterizing 32 terpene synthases (TPSs) from P. lactiflora, we successfully constructed 24 pESC-Trp-PlTPS expression vectors. Through expression in Saccharomyces cerevisiae engineered strains, we identified four mono-TPSs and five sesqui-TPSs that produce 18 compounds, including eight monoterpenes and ten sesquiterpenes in vitro. This includes a bifunctional enzyme (PlTPS22). Additionally, PlTPS21 was characterized as a pinene synthase with α-pinene as its main product. The expression pattern of PlTPS21 aligns closely with the accumulation patterns of paeoniflorins and α-pinene in the plant, suggesting that PlTPS21 is a key enzyme in the biosynthesis of paeoniflorin. [ABSTRACT FROM AUTHOR]

Bridged cyclobutanes and sulfur heterocycles are currently under intense investigation as building blocks for pharmaceutical drug design. Two formal cycloaddition modes involving bicyclobutanes (BCBs) and pyridinium 1,4‐zwitterionic thiolate derivatives were described to rapidly expand the chemical space of sulfur‐containing bridged cyclobutanes. By using Ni(ClO4)2 as the catalyst, an uncommon higher‐order (5+3) cycloaddition of BCBs with quinolinium 1,4‐zwitterionic thiolate was achieved with broad substrate scope under mild reaction conditions. Furthermore, the first Lewis acid‐catalyzed asymmetric polar (5+3) cycloaddition of BCB with pyridazinium 1,4‐zwitterionic thiolate was accomplished. In contrast, pyridinium 1,4‐zwitterionic thiolates undergo an Sc(OTf)3‐catalyzed formal (3+3) reaction with BCBs to generate thia‐norpinene products, which represent the initial instance of synthesizing 2‐thiabicyclo[3.1.1]heptanes (thia‐BCHeps) from BCBs. Moreover, we have successfully used this (3+3) protocol to rapidly prepare thia‐BCHeps‐substituted analogues of the bioactive molecule Pitofenone. Density functional theory (DFT) computations imply that kinetic factors govern the (5+3) cycloaddition reaction between BCB and quinolinium 1,4‐zwitterionic thiolate, whereas the (3+3) reaction involving pyridinium 1,4‐zwitterionic thiolates is under thermodynamic control. [ABSTRACT FROM AUTHOR]

Introduction: This research aims to explore the molecular composition, antioxidant capabilities, and antibacterial effects of the essential oils from Tetraclinis articulateata and Juniperus phoenicea. Methods: Essential oils were extracted using hydrodistillation. Gas chromatography combined with mass spectrometry was used to determine the chemical makeup of essential oils. Two methods are used to assess the antioxidant activity of essential oils: the reduction of iron (ferric reducing antioxidant power or frap) and the trapping of the free radical 2,2-Diphenyl-1Picrylhydrazyl (DPPH). The antimicrobial potential of essential oils was assessed using the diffusion method on a solid-state disk in comparison to nine bacterial and seven fungal souches. Results and Discussion: The essential oil yields from Tetraclinis articulata and Juniperus phoenicea are 0.46% ± 0.02% and 0.83% ± 0.05%, respectively. According to CG/SM's chromatographic analyses, the predominant constituent in the essential oil of J. Phoenicea is α-pinene (59.51%), while the main constituents in the essential oil of T. Articulata? are Bornyle acetate (18.91%) and camphor (28.48%). The assessment of antioxidant activities reveals intriguing antioxidant qualities in the essential oils of the species under investigation. T. Articulata essential oils yield the greatest results in the DPPH and FRAP tests, with CI50 values of around 266.9 ± 5.4 μg/mL and EC50 values of 433.16 ± 4.13 μg/mL, respectively. Except for Staphylococcus epidermidis, Staphylococcus aureus BLACT, and Pseudomonas aeroginosa, the two essential oils have demonstrated significant bactericidal activity against all bacterial and fungal souches (MIC <2 mg/mL et MBC <3.5 mg/mL). The inhibiting effect of these oils on bacterial and fungal development raises potential application areas in the food,cosmetic,and pharmaceutical industries. In addition, the current study investigated the potential antifungal, antibacterial, and antioxidant activities of the essential oils from Juniperus phoenicea and Tetraclinis articulate plants via the Glide molecular docking methodology, and most of these constituents were observed to be potent therapeutic agents. [ABSTRACT FROM AUTHOR]

A method for the synthesis of a nanostructured turpentine oil lyosol by bubbling an emulsion of turpentine oil in water with air in a mass ratio of 1:200 to 1:2200 by the separation of nanoparticles using nanofiltration has been proposed. Changing the mass ratio of turpentine oil to the aqueous phase during the synthesis was shown to influence the size of the resulting nanoparticles. An increase in the Z-average size of nanoparticles from 50 to 320 nm along with a gradual decreasing turpentine content from 1:200 to 1:1000 was observed. A further decrease in the turpentine load from 1:1000 to 1:2200 led to decreasing the Z-average particle size up to 160 nm. The fact of the formation of stable non-covalent complexes of the lyosol particles with fluorescein has been established. The fluorescein-stained lyosol particles were used to study the efficiency of their phagocytosis by chicken blood monocytes using confocal microscopy. The maximum efficiency of the lyosol phagocytosis by the chicken monocytes was observed when the Z-average lyosol particle size was ~ 50 nm, which was achieved with a turpentine dry matter ratio of 1:200 during the synthesis. [ABSTRACT FROM AUTHOR]

Heterogeneous oxidation by gas-phase oxidants is an important chemical transformation pathway of secondary organic aerosol (SOA) and plays an important role in controlling the abundance, properties, as well as climate and health impacts of aerosols. However, our knowledge on this heterogeneous chemistry remains inadequate. In this study, the heterogeneous oxidation of α-pinene ozonolysis SOA by hydroxyl (OH) radicals was investigated under both low and high relative humidity (RH) conditions, with an emphasis on the evolution of molecular composition of SOA and its RH dependence. It is found that the heterogeneous oxidation of SOA at an OH exposure level equivalent to 12 hr of atmospheric aging leads to particle mass loss of 60% at 25% RH and 95% at 90% RH. The heterogeneous oxidation strongly changes the molecular composition of SOA. The dimer-to-monomer signal ratios increase dramatically with rising OH exposure, in particular under high RH conditions, suggesting that aerosol water stimulates the reaction of monomers with OH radicals more than that of dimers. In addition, the typical SOA tracer compounds such as pinic acid, pinonic acid, hydroxy pinonic acid and dimer esters (e.g., C 17 H 26 O 8 and C 19 H 28 O 7) have lifetimes of several hours against heterogeneous OH oxidation under typical atmospheric conditions, which highlights the need for the consideration of their heterogeneous loss in the estimation of monoterpene SOA concentrations using tracer-based methods. Our study sheds lights on the heterogeneous oxidation chemistry of monoterpene SOA and would help to understand their evolution and impacts in the atmosphere. [Display omitted] [ABSTRACT FROM AUTHOR]

The gas-phase rotational spectra of α-pinene oxide have been recorded using a chirped-pulse Fourier transform microwave spectrometer in the 6–18 GHz frequency range. The parent species and all heavy atom isotopologues (13C and 18O) have been observed in their natural abundance. The experimental rotational constants of all isotopic species observed have been determined and used to obtain the substitution (rs) and the effective (r0) structures of the most stable conformer of α-pinene oxide. Calculations using the density functional theories B3LYP, M06-2X, and MN15-L and the ab initio method MP2 level of theory were carried out to check their performance against experimental results. The structure of the heavy atom's skeleton of α-pinene oxide has been compared to that of α-pinene and has shown that epoxidation does not overly affect the structure of the bicycle, validating its robustness. Furthermore, the structural features have been compared to those of other bicyclic molecules, such as nopinone and β-pinene. [ABSTRACT FROM AUTHOR]

The western drywood termite, Incisitermes minor (Hagen), causes significant economic damage to wood structures in the United States of America, especially California. When infestation is not widespread, localized insecticide injections may be useful for remedial control. However, the extensive gallery structure of drywood termites and their tendency to aggregate at specific parts of the galleries can impact the efficacy of localized insecticide injection. Chemicals that attract termites from a distance may improve the localized insecticide injection by increasing the number of termites contacting the insecticide residues. Two volatile terpenes, α-pinene and β-pinene, commonly found in many coniferous timber trees, were applied to artificial termite galleries to determine if termites were attracted from their original aggregation site. Furthermore, we examined if adding these pinenes would improve the overall efficacy of some insecticide products for drywood termite control. Behavioral assay results showed that the treatment with pinenes increased the likelihood that drywood termites would leave their original aggregation site and contact the treated part of the gallery. When tested with the pesticide products applied in a small area away from the termite aggregation, β-pinene significantly accelerated the time course of mortality for the aqueous fipronil. The efficacy of disodium octaborate tetrahydrate dust was not influenced by the addition of pinenes. Implications for drywood termite management and future research directions are discussed. [ABSTRACT FROM AUTHOR]

Detecting volatile organic compounds (VOCs) emitted from different plant species and their organs can provide valuable information about plant health and environmental factors that affect them. For example, limonene emission can be a biomarker to monitor plant health and detect stress. Traditional methods for VOC detection encounter challenges, prompting the proposal of novel approaches. In this study, we proposed integrating electrospinning, molecular imprinting, and conductive nanofibers to fabricate limonene sensors. In detail, polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) served here as fiber and cavity formers, respectively, with multiwalled carbon nanotubes (MWCNT) enhancing conductivity. We developed one-step monolithic molecularly imprinted fibers, where S(−)-limonene was the target molecule, using an electrospinning technique. The functional cavities were fixed using the UV curing method, followed by a target molecule washing. This procedure enabled the creation of recognition sites for limonene within the nanofiber matrix, enhancing sensor performance and streamlining manufacturing. Humidity was crucial for sensor working, with optimal conditions at about 50% RH. The sensors rapidly responded to S(−)-limonene, reaching a plateau within 200 s. Enhancing fiber density improved sensor performance, resulting in a lower limit of detection (LOD) of 137 ppb. However, excessive fiber density decreased accessibility to active sites, thus reducing sensitivity. Remarkably, the thinnest mat on the fibrous sensors created provided the highest selectivity to limonene (Selectivity Index: 72%) compared with other VOCs, such as EtOH (used as a solvent in nanofiber development), aromatic compounds (toluene), and two other monoterpenes (α-pinene and linalool) with similar structures. These findings underscored the potential of the proposed integrated approach for selective VOC detection in applications such as precision agriculture and environmental monitoring. [ABSTRACT FROM AUTHOR]

(±)‐Pinenyllithium·TMEDA or (tetramethylethylenediamine‐κ2N,N′)(η3‐6,6‐dimethyl‐2‐methylenebicyclo[3.1.1]heptyl)lithium, [Li(C10H15)(C6H16N2)], is readily prepared from β‐pinene, butyllithium and TMEDA, and the racemic material preferentially crystallizes even from 96:4 (92% ee) mixtures of (−)‐ and (+)‐β‐pinene, respectively. The structure is monomeric, with the geminal‐dimethyl bridge of the bicyclic structure shielding one face of the allyl system, restricting the lithium to the opposite face and preventing the Li–allyl–Li aggregation observed with some other allyllithium systems. The symmetry of the allyl system, bond lengths, bond angles and out‐of‐plane deviations are compared to existing structures. In addition, a much older structure of this complex is compared to this very recent one. [ABSTRACT FROM AUTHOR]

Whereas the cationic homopolymerization of β-pinene and isobutene (IB) have been extensively studied, their copolymerization is still very scarce, and the conditions under which copolymerization can occur are limited to extremely low temperatures. Moreover, the application of the copolymer has not been reported. Here, a series of room-temperature copolymerizations of β-pinene and IB, using group 13 compounds as catalysts, were conducted. The copolymerizations yielded a low molecular weight (Mn ~ 103) and a narrow molecular weight distribution (Mw/Mn < 2.0) copolymer, with a satisfactory yield at various comonomer feeds, and their glass transition temperature was predictable from the comonomer composition. Furthermore, the tackifying property of the obtained copolymer was investigated using a 180° peel adhesion test. A blend polymer of the copolymer and a styrene-isoprene triblock copolymer showed a high peeling force (0.58 ± 0.14 N/10 mm) and a glass transition temperature low enough for its application as a pressure-sensitive adhesive. [ABSTRACT FROM AUTHOR]

This study investigated the mitigating effects of spermidine on salinity-stressed yarrow plants (Achillea millefolium L.), an economically important medicinal crop. Plants were treated with four salinity levels (0, 30, 60, 90 mM NaCl) and three spermidine concentrations (0, 1.5, 3 μM). Salinity induced electrolyte leakage in a dose-dependent manner, increasing from 22% at 30 mM to 56% at 90 mM NaCl without spermidine. However, 1.5 μM spermidine significantly reduced leakage across salinities by 1.35–11.2% relative to untreated stressed plants. Photosynthetic pigments (chlorophyll a, b, carotenoids) also exhibited salinity- and spermidine-modulated responses. While salinity decreased chlorophyll a, both spermidine concentrations increased chlorophyll b and carotenoids under most saline conditions. Salinity and spermidine synergistically elevated osmoprotectants proline and total carbohydrates, with 3 μM spermidine augmenting proline and carbohydrates up to 14.4% and 13.1% at 90 mM NaCl, respectively. Antioxidant enzymes CAT, POD and APX displayed complex regulation influenced by treatment factors. Moreover, salinity stress and spermidine also influenced the expression of linalool and pinene synthetase genes, with the highest expression levels observed under 90 mM salt stress and the application of 3 μM spermidine. The findings provide valuable insights into the responses of yarrow plants to salinity stress and highlight the potential of spermidine in mitigating the adverse effects of salinity stress. [ABSTRACT FROM AUTHOR]

Polyolefins comprise some of the most abundant plastics, but their recycling faces several difficulties. This work focuses on the recycling of high-density polyethylene (HDPE) through the dissolution–precipitation method. Although few works have been published on this topic, this is an extremely promising plastic recycling strategy. However, for this kind of process to become a viable alternative, the replacement of conventional solvents by green solvents and the minimization of energy usage need to be implemented. In this work, several natural terpenes were screened based on COSMO-SAC predictions for HDPE solubility, and three were tested: limonene, α-pinene, and p-cymene. These solvents showed a good capability of dissolving HDPE, confirming the computational predictions. The dissolution and precipitation conditions were optimized based on the results for limonene, with the optimal values being 3 wt% initial concentration of the polymer in the solvent, a dissolution period of 10 min at a temperature of 110 °C, and an antisolvent/solvent ratio of 2/1. Comparing both HDPE and solvent recoveries for the three selected solvents, the best results were obtained for α-pinene as the solvent and ethanol as the antisolvent. The recovered HDPE samples were analyzed by TGA, FTIR, and DSC, showing little modification between the recycled and pristine materials. Scaling up of the process and solvent reuse were also investigated. Through process simulation, it was concluded that solvent recovery and reuse is a crucial step for economic viability. HDPE dissolution–precipitation with α-pinene was found to be a sustainable process from preliminary sustainability analysis, and the separation of HDPE and PET (polyethylene terephthalate) was successfully carried out. [ABSTRACT FROM AUTHOR]

The anatomical, physiological, and environmental changes of plants can alter the production of essential oil. The present study aims to characterize the profit and chemical constituents of Lavandula dentata L and Rosmarinus officinalis L. essential oils (EO), grown under conditions of stress by solar, water and soil radiation. A completely randomized design (CRD) was used in triplicate. The biomass analysis showed that in both plants, the best results were obtained when it was subjected to lighting, shading and 100% fertilization, but there was the lowest profit of EO. The portion that had the lowest biomass, showed the highest profit of EO. In the EO of Lavandula dentata L there were as major compounds: nerol, linalol and Myrcene, respectively, as the product with the lowest profit, eucalyptol stood out, followed by camphor and fenchone. The EO of Rosmarinus officinalis L with the lowest profit showed alpha-pinene as the major constituent, followed by camphor, 1.8 cineol, alpha-Terpinolene and linalol, and the EO with the highest profit was caryophyllene. The constituents of the EO showed different results when comparing the products obtained from the highest and lowest profit, both qualitatively and quantitatively, which shows that plants under different stress conditions affect the production of these secondary compounds, which may indicate differences in pharmacological actions.

Urbanization modifies ecosystem conditions and evolutionary processes. This includes air pollution, mostly as tropospheric ozone (O3), which contributes to the decline of urban and peri‐urban forests. A notable case are fir (Abies religiosa) forests in the peripheral mountains southwest of Mexico City, which have been severely affected by O3 pollution since the 1970s. Interestingly, some young individuals exhibiting minimal O3—related damage have been observed within a zone of significant O3 exposure. Using this setting as a natural experiment, we compared asymptomatic and symptomatic individuals of similar age (≤15 years old; n = 10) using histologic, metabolomic, and transcriptomic approaches. Plants were sampled during days of high (170 ppb) and moderate (87 ppb) O3 concentration. Given that there have been reforestation efforts in the region, with plants from different source populations, we first confirmed that all analyzed individuals clustered within the local genetic group when compared to a species‐wide panel (Admixture analysis with ~1.5K SNPs). We observed thicker epidermis and more collapsed cells in the palisade parenchyma of needles from symptomatic individuals than from their asymptomatic counterparts, with differences increasing with needle age. Furthermore, symptomatic individuals exhibited lower concentrations of various terpenes (ß‐pinene, ß‐caryophylene oxide, α‐caryophylene, and ß‐α‐cubebene) than asymptomatic trees, as evidenced through GC–MS. Finally, transcriptomic analyses revealed differential expression for 13 genes related to carbohydrate metabolism, plant defense, and gene regulation. Our results indicate a rapid and contrasting phenotypic response among trees, likely influenced by standing genetic variation and/or plastic mechanisms. They open the door to future evolutionary studies for understanding how O3 tolerance develops in urban environments, and how this knowledge could contribute to forest restoration. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue of the journal Catalysts titled "Catalytic Epoxidation Reaction." The special issue focuses on the research efforts in catalyst and process intensification in the epoxidation of various substances, including gaseous molecules, molecules in multiphase, triglycerides, terpenes, and olefins. The special issue includes nine research articles and two reviews, covering topics such as kinetic modeling, catalyst preparation and characterization, and enzymatic catalysis. The articles provide insights into the epoxidation process and offer potential advancements for future research in this field. [Extracted from the article]

This article discusses the chemical composition and antimicrobial activity of the essential oil from the leaves and twigs of Knema tonkinensis. The essential oil was analyzed using Gas Chromatography-Mass Spectrometer, and a total of eighty-six compounds were identified. The major constituents of the oils were β-pinene, α-pinene, bicyclogermacrene, caryophyllene, and copaene. The essential oil from the leaves showed strong antimicrobial activity against various bacteria and yeast, while the essential oil from the twigs also exhibited antimicrobial activity against certain bacteria. This research was supported by the Ph.D. Scholarship Programme of Vingroup Innovation. [Extracted from the article]

• Community composting was systematically studied in terms of atmospheric emissions. • Ammonia, methane, nitrous oxide, VOC and odours were measured in several sites. • Community compost presents a good quality, especially in terms of stability. • VOC families were diverse, although terpenes were the predominant compounds. • The age of the material and turning dramatically affects gaseous emissions. Composting has demonstrated to be an effective and sustainable technology to valorise organic waste in the framework of circular economy, especially for biowaste. Composting can be performed in various technological options, from full-scale plants to community or even individual composters. However, there is scarce scientific information about the potential impact of community composting referred to gaseous emissions. This work examines the emissions of methane and nitrous oxide as main GHG, ammonia, VOC and odours from different active community composting sites placed in Spain, treating kitchen, leftovers and household biowaste. Expectedly, the gaseous emissions have an evident relation with the composting progress, represented mainly by its decrease as temperature or biological activity decreases. GHG and odour emission rates ranged from 5.3 to 815.2 mg CO 2eq d-1 kg-1VS and from 69.8 to 1088.5 ou d-1 kg-1VS, respectively, generally being lower than those find in open-air full-scale composting. VOC characterization from the community composting gaseous emissions showed a higher VOC families' distribution in the emissions from initial composting phases, even though terpenes such as limonene, α-pinene and β-pinene were the most abundant VOC along the composting process occurring in the different sites studied. The results presented in this study can be the basis to evaluate systematically and scientifically the numerous current projects for a worldwide community composting implementation in decentralised biowaste management schemes. [ABSTRACT FROM AUTHOR]

Bioactive compounds blended with synthetic polymers constitute an effective alternative for tailored materials design in advanced applications. Biological functionalities are easily incorporated, and the materials' overall performance can be improved using this technique. The present work introduces the production and characterization of electrospun scaffolds comprised poly(vinyl alcohol), chitosan, and oligo(β-pinene) with potential for tissue engineering. Oligo(β-pinene) presents many biological functionalities of interest, especially cytoprotective activity. The scaffolds' structure, processing, properties, and performance relationships were evaluated. The materials presented an average fiber diameter of 159 nm, which was increased with the oligo(β-pinene) addition in the polymer matrix. There was an overall trend of crystallinity decrease (from 21.02 to 6.4%) with the incorporation of the oligomer. The polymers' ∆Hm and Tm increased from 28.43 to 35.51 J g−1 and from 190.54 to 194.10 °C, respectively, with the addition of oligo(β-pinene). The presence of a few fiber defects appeared upon oligomer inclusion. However, the overall thermal performance of the scaffolds improved with the increase in oligo(β-pinene) content on the nanofibers. Essays of cell proliferation revealed significant benefits from oligo(β-pinene) inclusion on the blends tested. Biocompatibility improvement of up to 21.5% was noted compared to the control. Thus, incorporating oligo(β-pinene) in poly(vinyl alcohol)-chitosan electrospun nanofibers constitutes a renewable option to enhance the scaffolds' properties and biocompatibility. [ABSTRACT FROM AUTHOR]

Highly oxygenated molecules (HOMs) from the atmospheric oxidation of biogenic volatile organic compounds are important contributors to secondary organic aerosol (SOA). Organic peroxy radicals (RO 2) and hydroperoxy radicals (HO 2) are key species influencing the HOM product distribution. In laboratory studies, experimental requirements often result in overemphasis on RO 2 cross-reactions compared to reactions of RO 2 with HO 2. We analyzed the photochemical formation of HOMs from α -pinene and their potential to contribute to SOA formation under high (≈1 /1) and low (≈1 /100) HO2/RO2 conditions. As HO2/RO2 > 1 is prevalent in the daytime atmosphere, sufficiently high HO2/RO2 is crucial to mimic atmospheric conditions and to prevent biases by low HO2/RO2 on the HOM product distribution and thus SOA yield. Experiments were performed under steady-state conditions in the new, continuously stirred tank reactor SAPHIR-STAR at Forschungszentrum Jülich. The HO2/RO2 ratio was increased by adding CO while keeping the OH concentration constant. We determined the HOM's SOA formation potential, considering its fraction remaining in the gas phase after seeding with (NH 4)2 SO 4 aerosol. An increase in HO2/RO2 led to a reduction in SOA formation potential, with the main driver being a ∼ 60 % reduction in HOM-accretion products. We also observed a shift in HOM-monomer functionalization from carbonyl to hydroperoxide groups. We determined a reduction of the HOM's SOA formation potential by ∼ 30 % at HO2/RO2 ≈1 /1 compared to HO2/RO2 ≈ 1/100. Particle-phase observations measured a similar decrease in SOA mass and yield. Our study shows that too low HO2/RO2 ratios compared to the atmosphere can lead to an overestimation of SOA yields. [ABSTRACT FROM AUTHOR]

Nowadays, the effective processing of natural monoterpenes that constitute renewable biomass found in post-production waste into products that are starting materials for the synthesis of valuable compounds is a way to ensure independence from non-renewable fossil fuels and can contribute to reducing global carbon dioxide emissions. The presented research aims to determine, based on DFT calculations, the activity and reactivity of limonene, an organic substrate used in previous preparative analyses, in comparison to selected monoterpenes such as cymene, pinene, thymol, and menthol. The influence of the solvent model was also checked, and the bonds most susceptible to reaction were determined in the examined compounds. With regard to EHOMO, it was found that limonene reacts more easily than cymene or menthol but with more difficultly than thymol and pienene. The analysis of the global chemical reactivity descriptors "locates" the reactivity of limonene in the middle of the studied monoterpenes. It was observed that, among the tested compounds, the most reactive compound is thymol, while the least reactive is menthol. The demonstrated results can be a reference point for experimental work carried out using the discussed compounds, to focus research on those with the highest reactivity. [ABSTRACT FROM AUTHOR]

Ferula latisecta belongs to the Ferula genus and is endemic to Iran. The present study aims to extract the essential oil of F. latisecta oleo-gum-resin for the first time and evaluate its phytochemistry and antimicrobial activity. The essential oil was extracted using a Clevenger-type hydrodistillation apparatus. The essential oil constituents were identified and quantified using GC and GC/MS methods. The antimicrobial activity of the essential oil was assayed against two Gram-negative bacteria, Acinetobacter baumannii and Pseudomonas aeruginosa, a Gram-positive bacterium, Staphylococcus aureus, and a fungal strain, Candida krusei using the broth microdilution method to determine MIC and MBC values. The results showed that the essential oil was rich in β- and α-pinene with 30.72% and 25.07% content, respectively. Additionally, the essential oil contained a significant amount of sulfur-containing compounds (7.49%) such as (E)-sec-butyl propenyl disulfide (4.21%), (Z)-sec-butyl propenyl disulfide (2.34%), and hexamethylene sulfide (0.94%). According to the results, the essential oil exhibited high inhibitory activity against C. krusei fungi, with MIC and MBC values of 2 μg/mL, which were more potent than amphotericin B (MIC: 8 and MBC: 32 μg/mL), as a standard antifungal agent. Additionally, the essential oil showed significant antibacterial activity against A. baumannii, with MIC and MBC values of 32 μg/mL, which were more potent than cefixime. Furthermore, the essential oil exhibited moderate activity against S. aureus with MIC and MBC values of 16 μg/mL. This study introduces a new oleo-gum resin from F. latisecta, with a high content of terpenoids and strong antimicrobial potency. [ABSTRACT FROM AUTHOR]

Indole (ind) is a nitrogen-containing heterocyclic volatile organic compound commonly emitted from animal husbandry and from different plants like maize with global emissions of 0.1 Tg yr -1. The chemical composition and optical properties of indole secondary organic aerosol (SOA) and brown carbon (BrC) are still not well understood. To address this, environmental chamber experiments were conducted to investigate the oxidation of indole at atmospherically relevant concentrations of selected oxidants (OH radicals and O 3) with or without NO 2. In the presence of NO 2 , the SOA yields decreased by more than a factor of 2, but the mass absorption coefficient at 365 nm (MAC 365) of ind-SOA was 4.3 ± 0.4 m 2 g -1 , which was 5 times higher than that in experiments without NO 2. In the presence of NO 2 , C 8 H 6 N 2 O 2 (identified as 3-nitroindole) contributed 76 % to all organic compounds detected by a chemical ionization mass spectrometer, contributing ∼ 50 % of the light absorption at 365 nm (Abs 365). In the absence of NO 2 , the dominating chromophore was C 8 H 7 O 3 N, contributing to 20 %–30 % of Abs 365. Indole contributes substantially to the formation of secondary BrC and its potential impact on the atmospheric radiative transfer is further enhanced in the presence of NO 2 , as it significantly increases the specific light absorption of ind-SOA by facilitating the formation of 3-nitroindole. This work provides new insights into an important process of brown carbon formation by interaction of two pollutants, NO 2 and indole, mainly emitted by anthropogenic activities. [ABSTRACT FROM AUTHOR]

Introduction: Despite the increasing number of essential oils being reported on their potential therapeutic effects, some remain relatively unknown on their biological properties. That is the case of the essential oils obtained from copaiba (Copaifera officinalis L.), wintergreen (Gaultheria fragrantissima Wall.), everlasting (Helichrysum italicum (Roth) G.Don) and clove (Syzygium aromaticum (L.) Merr. & L.M.Perry), commonly labelled as being useful on the amelioration of conditions with an inflammatory background. Methods: To further broaden the current knowledge on the four essential oils, commercially available samples were approached on their effects upon a series of mediators that are involved on the inflammatory and oxidative response, both through in vitro cell-free and cell-based assays (5-lipoxygenase activity, lipid peroxidation, free radical and nitric oxide radical scavenging properties or tyrosinase inhibition). Results: The four oils proved to be active at some of the concentrations tested in most of the performed assays. Significant differences were found between the essential oils, S. aromaticum proving to tbe the most active, followed by G. fragrantissima against 5-lipoxygenase (5-LOX) and linoleic acid peroxidation, proving their potential use as antioxidants and anti-inflammatory agents. In fact, the IC50 value of S. aromaticum in the 5-LOX assay was 62.30 μg mL-1. Besides S. aromaticum efficiently scavenged superoxide radicals generated by xanthine/xanthine oxidase, displaying an IC50 value of 135.26 μg mL-1. The essential oil obtained from H. italicum exhibited a significant decrease in the nitric oxide levels on BV-2 cells, showing its potential as a cytoprotective agent against toxic damage. Copaiba oil ranked first as the most potent tyrosinase inhibitor, exhibiting an IC50 98.22 μg mL-1. Conclusion: More studies are needed to describe the essential oils properties, but these results confirm the potential of these essential oils as anti-inflammatory and antioxidant agents. [ABSTRACT FROM AUTHOR]

Polyamides (PA) are among the most essential and versatile polymers due to their outstanding characteristics, for example, high chemical resistance and temperature stability. Furthermore, nature‐derived monomers can introduce hard‐to‐synthesize structures into the PAs for unique polymer properties. Pinene, as one of the most abundant terpenes in nature and its presumable stability‐giving bicyclic structure, is therefore highly promising. This work presents simple anionic ring‐opening polymerizations of β‐pinene lactam (AROP) in‐bulk and in solution. PAs with high molecular weights, suitable for further processing, are produced. Their good mechanical, thermal (Tds up to 440 °C), and transparent appearance render them promising high‐performance biomaterials. In the following, the suitability of different initiators is discussed. Thereby, it is found that NaH is the most successful for in‐bulk polymerization, with a degree of polymerization (DP) of about 322. For solution‐AROP, iPrMgCl·LiCl is successfully used for the first time, achieving DPs up to about 163. The obtained PAs are also hot‐pressed, and the dynamic mechanical properties are analyzed. [ABSTRACT FROM AUTHOR]

To explore novel terpenoid repellents, 22 candidate terpenoid derivatives were synthesized and tested for their electroantennogram (EAG) responses and repellent activities against Aedes albopictus. The results from the EAG experiments revealed that 5-(2-hydroxypropan-2-yl)-2-methylcyclohex-2-en-1-yl formate (compound 1) induced distinct EAG responses in female Aedes albopictus. At concentrations of 0.1, 1, 10, 100, and 1000 mg/L, the EAG response values for compound 1 were 179.59, 183.99, 190.38, 193.80, and 196.66 mV, demonstrating comparable or superior effectiveness to DEET. Repellent activity analysis indicated significant repellent activity for compound 1, closest to the positive control DEET. The in silico assessment of the ADMET profile of compound 1 indicates that it successfully passed the ADMET evaluation. Molecular docking studies exhibited favourable binding of compound 1 to the active site of the odorant binding protein (OBP) of Aedes albopictus, involving hydrophobic forces and hydrogen bond interactions with residues in the OBP pocket. The QSAR model highlighted the influential role of hydrogen-bonding receptors, positively charged surface area of weighted atoms, polarity parameters of molecules, and maximum nuclear-nuclear repulsion force of carbon-carbon bonds on the relative EAG response values of the tested compounds. This study holds substantial significance for the advancement of new terpenoid repellents. [ABSTRACT FROM AUTHOR]

Rosmarinus officinalis L. is a Mediterranean medicinal and aromatic plant, widely used in several industries. The present study aimed to characterize the chemical composition of volatile compounds, encompassing essential oils (EO): hydrosol extract (HE): and water residue extract (WRE1). Additionally, the investigation focused on non-volatile components, including powder phenolic extract (PPE): water residue extract (WRE2): and solid residue extract (SRE): while also assessing their antioxidant and antibacterial activities. The chemical compositions of volatile components were determined by using a Gas Chromatograph equipped with a Mass Spectrometer (GC/MS): while polyphenol extracts were analyzed using Ultra-High-Performance Liquid Chromatograph equipped with a photodiode array detection Mass Spectrometer (UHPLC-DAD-ESI/MS). The antioxidant activity was determined by 1,1-diphenyl-2-picrylhydrazyl free radical scavenging (DPPH) and ferric reducing antioxidant power (FRAP): while the antibacterial effect was evaluated against four pathogenic bacterial strains using disc diffusion and broth microdilution methods. The GC/MS analysis showed that R. officinalis EO was dominated by 1,8-cineole (47.70%) and α-pinene (15.50%). 1,8-cineole (56.67%) and camphor (26.27%) were found as the predominant constituents of HE, while volatile components of WRE1 were mainly dominated by camphor (10.11%). The UHPLC-DAD-ESI/MS analysis revealed the existence of a plethora of polyphenolic components. In PPE and SRE, the predominating compounds were carnosic acid and carnosol, respectively. Rosmarinic acid was the main constituent in WRE2. The results of DPPH free radical scavenging and FRAP activities showed that PPE exhibited strong antioxidant activity, followed by SRE and WRE2. EO and HE showed moderate antioxidant activity, while volatile components of WRE1 exhibited the lowest antioxidant effect. Regarding the antibacterial activity, PPE and SRE indicated the highest effect against the pathogenic bacteria, while WRE1 volatile components had the weakest antibacterial activity. The conducted study showed that material plant left after hydrodistillation of R. officinalis may be used as a new source of bioactive volatile and polyphenolic components with valuable pharmacological activities. [ABSTRACT FROM AUTHOR]

Effects of hot air circulation roasting temperature on cashew nut sensory and aroma profiles were assessed in this study. Optimal roasting at 130°C for 20 min yielded a uniform, glossy appearance and rapid water loss. Sensory and electronic nose (E‐nose) analyses indicated enhanced sweet, milky, and fatty aromas. Gas chromatography–mass spectrometry identified more than 180 volatile compounds. Roasting at 150°C for 20 min produced a burnt aroma, with a decrease in alkenes and aromatic hydrocarbons and an increase in alkanes, acids, ketones, and pyrazines. Principal component analysis distinguished between 130 and 150°C roasting samples, and key volatile compounds included phenylethanol, 1‐octen‐3‐ol, naphthalene, (−)‐alpha pinene, trans caryophyllene, 2,5‐dimethylpyrazine, 2‐methylbutyr‐aldehyde, heptaldehyde, 2,3,5‐trimethylpyrazine, and n‐octanol. Compared to traditional roasting, hot air circulation roasting offers efficiency, convenience, energy savings, and environmental benefits. Practical applications: Cashew nuts are esteemed as a nutritious treat mainly due to their profound taste and elevated nutrient content. This research explored the influence of applying hot air circulation during the roasting procedure on various aspects of physical and chemical properties, flavor, and energy consumption. By establishing a systematic theoretical model of the process, this work can effectively manipulate the roasting parameters to attain an optimal flavor profile desirable for cashew nuts. Moreover, the efficiency of this novel approach outperforms conventional techniques, offering substantial energy cost savings, and showcasing its virtues of high efficacy, eco‐friendliness, and environmental preservation. The investigation revealed that utilizing hot air circulation leads to cashew nuts possessing a superior gustatory sensation and nutritional profile. Therefore, it can safely be stated that hot air circulation roasting could serve as an exemplary methodology for household nut manufacturing, thereby warranting further consideration of this innovative technique in private nut production. [ABSTRACT FROM AUTHOR]

We present an evaluation of the regional chemical transport model (CTM) WRF-CHIMERE (v2020r2) for the formation of biogenic secondary organic aerosol (BSOA) with a focus over the Finnish boreal forest. Formation processes of biogenic aerosols are still affected by different sources of uncertainties, and model predictions vary greatly depending on the levels of details of the adopted chemical and emissions schemes. In this study, air quality simulations were conducted for the summer of 2019 using different organic aerosol (OA) schemes (as currently available in the literature) to treat the formation of BSOA. First, we performed a set of simulations in the framework of the volatility basis set (VBS) scheme carrying different assumptions for the treatment of the aging processes of BSOA. The results of the model were compared against high-resolution (i.e., 1 h) organic aerosol mass and size distribution measurements performed at the Station for Measuring Ecosystem–Atmosphere Relations (SMEAR-II) site located in Hyytiälä, in addition to other gas-phase species such as ozone (O 3), nitrogen oxides (NO x), and biogenic volatile organic compound (BVOC) measurements of isoprene (C 5 H 10) and monoterpenes. We show that WRF-CHIMERE could reproduce well the diurnal variation of the measured OA concentrations for all the investigated scenarios (along with the standard meteorological parameters) as well as the increase in concentrations during specific heat wave episodes. However, the modeled OA concentrations varied greatly between the schemes used to describe the aging processes of BSOA, as also confirmed by an additional evaluation using organic carbon (OC) measurement data retrieved from the EBAS European databases. Comparisons with isoprene and monoterpene air concentrations revealed that the model captured the observed monoterpene concentrations, but isoprene was largely overestimated, a feature that was mainly attributed to the overstated biogenic emissions of isoprene. We investigated the potential consequences of such an overestimation by inhibiting isoprene emissions from the modeling system. Results indicated that the modeled BSOA concentrations increased in the northern regions of the domain (e.g., Finland) compared to southern European countries, possibly due to a shift in the reactions of monoterpene compounds against available radicals, as further suggested by the reduction in α -pinene modeled air concentrations. Finally, we briefly analyze the differences in the modeled cloud liquid water content (clwc) among the simulations carrying different chemical schemes for the treatment of the aging processes of BSOA. The results of the model indicated an increase in clwc values at the SMEAR-II site, for simulations with higher biogenic organic aerosol loads, most likely as a result of the increased number of biogenic aerosol particles capable of activating cloud droplets. [ABSTRACT FROM AUTHOR]

α‐Pinene, α‐terpineol, and 1,8‐cineole are compounds naturally present in essential oils, although their amounts vary from oil to oil. Although several studies have reported their antibacterial and antioxidant effects, there are few reports on the synergistic or antagonistic effects of their combinations. The objective of this study was to investigate the combined antibacterial effect of these three compounds. To our knowledge, this is the first report on the prediction of their optimal combination using the mixture design approach. The experimental antibacterial activity of the α‐pinene, α‐terpineol, and 1,8‐cineole mixtures depended on the proportion of each compound in the mixture and the target strain, with minimum inhibitory concentrations (MIC) ranging from 0.31 to 1.85 mg/mL. Using the increased simplex‐centroid mixture design, the mixture containing 0.33% of each molecule proved to be the most effective against Bacillus cereus and had the lowest MIC values. In addition, α‐pinene, α‐terpineol, and 1,8‐cineole showed significant antioxidant activity against 2,2‐picryl‐1‐hydrazyl radical (DPPH), with IC50 values of 24.53 ± 0.05, 65.63 ± 0.71, and 63.58 ± 0.01 μg/mL, respectively. Statistical planning and the development of utility profiles of the substance mixtures can predict the optimal composition that will exhibit the highest antibacterial activity against B. cereus as well as antioxidant properties. Furthermore, the synergistic effect of the mixtures can contribute significantly to their successful use as natural preservatives in various applications. [ABSTRACT FROM AUTHOR]

Background: Trichomoniasis is one of the most common sexually transmitted infections worldwide. The growing concern of drug resistance of this infection has cautioned the need for new drug development. We evaluated the potential antiproliferative and apoptotic effect of a-pinene and tannic acid (TA) on Trichomonas vaginalis cells. In addition, the cytotoxicity of agents on Vero cells was investigated. Methods: Trichomonas cells were axenically cultured in TYI-S-33 medium. In vitro antiproliferative activity of a-pinene, TA, and metronidazole was investigated against Trichomonas cells. The assays were carried out in triplicate using microtiter plate and trypan blue staining method. Annexin V/PI staining with flow cytometry was used to evaluate apoptosis induction. In addition, the cytotoxic effect was measured by MTT assay. Results: α-Pinene and TA exhibited significant inhibition of the Trichomonas cells and the lowest IC50 values were 22.9 µg/ml and 140 µg/ml at 48 hours' incubation, respectively. The CC50 was found at 116 μg/ml for β-pinene and 473 μg/ml for TA, after 48 hours of treatment. The flow cytometry study demonstrated that the natural compounds induced apoptosis in Trichomonas cells. After 24 hours of treatment, the induction of apoptosis was 5.2% - 36.6% at concentrations of 3.9 - 62.5 μg/ml for β-pinene and TA induced-apoptosis was 6.1% - 53.8% at concentrations of 125-2000 μg/ml. Conclusion: Although the results show the antiproliferative and apoptotic effect of a-pinene and TA on Trichomonas cells, in vivo studies are needed to further clarify the effects of these compounds. [ABSTRACT FROM AUTHOR]

Stabilized Criegee intermediates (SCIs) and organic peroxy radicals (RO 2) are critical in atmospheric oxidation processes and secondary organic aerosol (SOA) formation. However, the influence of temperature on their corresponding reaction mechanisms in SOA formation is unclear. Through utilizing formic acid as a SCI scavenger and regulating the ratio of hydroperoxyl radials (HO 2) to RO 2 ([HO 2]/[RO2 ]) from ∼ 0.3 to ∼ 1.9 using different concentrations of CO, the roles of RO 2 and SCIs in SOA formation were investigated from 248 to 298 K, particularly for dimer formation in β -pinene ozonolysis. The SOA yield increased by 21 % from 298 to 273 K, while it decreased by 40 % from 273 to 248 K. Both changing [HO 2]/[RO2 ] and scavenging SCIs significantly affect SOA yield and composition. SCI reactions accounted for more than 40 % of dimer and SOA mass formation for all temperatures. Increasing [HO 2]/[RO2 ] inhibited dimer and SOA formation, and this inhibition became larger with decreasing temperature. Compared to low [HO 2]/[RO2 ] (0.30–0.34), the dimer abundance at high [HO 2]/[RO2 ] (1.53–1.88) decreased by about 31 % at 298 K and 70 % at 248 K. [HO 2]/[RO2 ] has a specific impact on SCI-controlled dimers at lower temperatures by especially influencing the C 9 –SCI reactions with RO 2. The dimers formed from C 9 –SCI reactions with RO 2 were estimated to decrease by 61 % at high [HO 2]/[RO2 ] compared to low [HO 2]/[RO2 ] at 248 K. The high reactivity and substantial contribution to SOA of β -pinene-derived SCIs at lower temperatures observed in this study suggest that monoterpene-derived SCI reactions should be accounted for in describing colder regions of the atmosphere. [ABSTRACT FROM AUTHOR]

Alpha-pinene is one of the main defensive components in conifers. Monochamus alternatus (Coleoptera: Cerambycidae), a wood borer feeding on Pinaceae plants, relies on its detoxifying enzymes to resist the defensive terpenoids. Here, we assayed the peroxide level and GST activity of M. alternatus larvae treated with different concentrations of α-pinene. Meanwhile, a gst gene (MaGSTe3) was isolated and analyzed. We determined its expression level and verified its function. The results showed that α-pinene treatment led to membrane lipid peroxidation and thus increased the GST activity. Expression of MaGSTe3 was significantly upregulated in guts following exposure to α-pinene, which has a similar pattern with the malonaldehyde level. In vitro expression and disk diffusion assay showed that the MaGSTe3 protein had high antioxidant capacity. However, RNAi treatment of MaGSTe3 did not reduce the hydrogen peroxide and malonaldehyde levels, while GST activity was significantly reduced. These results suggested MaGSTe3 takes part in α-pinene adaptation, but it does not play a great role in the resistance of M. alternatus larvae to α-pinene. [ABSTRACT FROM AUTHOR]

Sensory parameters as well as the volatile and non-volatile compound profiles of sixteen carrot cultivars were recorded to obtain insight into consumer preference decisions. The sensory test was carried out with a consumer panel of 88 untrained testers allowing a clear acceptance-based differentiation of the cultivars. Five individual sensory characters (sweetness, overall aroma, bitterness, astringency and off-flavor) supported this discrimination. Chemical analyses of volatile organic compounds, polyacetylenes, phenylpropanoids and sugars enabled us to correlate the influence of these ingredients on sensory perception. Higher concentrations of α-pinene, hexanal, styrene and acetophenone correlated with a better acceptance, as well as sweetness and overall aroma perception. In contrast, a low acceptance as well as a stronger perception of bitterness, astringency and off-flavor correlated with enhanced concentrations of camphene, bornylacetate, borneol, myristicine, falcarindiol, falcarindiol-3-acetate, laserin and epilaserin. The present study should support the development of new breeding strategies for carrot cultivars that better satisfy consumer demands. [ABSTRACT FROM AUTHOR]

Herein we describe Pd‐catalyzed cross‐coupling reaction of α‐pinene derivative – pinacarvone O‐methyl oxime (1) with aryl halides (2). Surprisingly, the formation of the C−C coupling product was accompanied by an unexpected opening of the pinene bicyclic structure. The (Z)‐2‐aryl‐4,4,5‐trimethylcyclohexa‐2,5‐dien‐1‐one O‐methyl oxime (3) was formed as the resulting product. The reaction conditions of the developed synthetic procedure were carefully optimized and the reaction mechanism was supposed on the basis of data obtained by structural and computational methods. [ABSTRACT FROM AUTHOR]

The preparation of sustainable polymers from renewable resources is a main task in modern polymer and materials chemistry. For this, terpenes, that have many functions in nature, are very important building blocks, e.g., due to their abundance, availability, structural diversity, and functionalities. Accordingly, many approaches have been and are currently developed for the utilization of many terpenes for the preparation of a variety of sustainable polymers and materials. These approaches are elucidated herein with a focus on different polymers (polyolefins, polyesters, polyamides, etc.) and their recent advances in synthesis and properties. [ABSTRACT FROM AUTHOR]

Polymers that can be extracted or manufactured from renewable resources such as sugars, natural acids, or terpenes are increasingly relevant. In this context, biobased lactones are a group of monomers that can be synthesized from renewable feedstocks and combine versatility with the ability to yield high-performing materials including both thermoplastics and thermosets. In this chapter, an overview of different kinds of catalytic ring-opening polymerization (ROP) mechanisms including coordination, organocatalyzed, and enzymatic reactions is discussed. ROP of renewable lactones to yield polyesters are classified by their origin. In particular, we report on recent advances in ROP of terpene-based precursors such as limonene and pinene that lead to a variety of caprolactone derivatives which are available for polymerization. Moreover, lactones that can be converted from sugars and natural acids (e.g., fatty acids, amino acids) will be discussed. [ABSTRACT FROM AUTHOR]

This review provides an overview of the biotransformation of limonene and α-pinene, which are commonly found in wood residues and citrus fruit by-products, to produce high-value-added products. Essential oils derived from various plant parts contain monoterpene hydrocarbons, such as limonene and pinenes which are often considered waste due to their low sensory activity, poor water solubility, and tendency to autoxidize and polymerise. However, these terpene hydrocarbons serve as ideal starting materials for microbial transformations. Moreover, agro-industrial byproducts can be employed as nutrient and substrate sources, reducing fermentation costs, and enhancing industrial viability. Terpenes, being secondary metabolites of plants, are abundant in byproducts generated during fruit and plant processing. Microbial cells offer advantages over enzymes due to their higher stability, rapid growth rates, and genetic engineering potential. Fermentation parameters can be easily manipulated to enhance strain performance in large-scale processes. The economic advantages of biotransformation are highlighted by comparing the prices of substrates and products. For instance, R-limonene, priced at US$ 34/L, can be transformed into carveol, valued at around US$ 530/L. This review emphasises the potential of biotransformation to produce high-value products from limonene and α-pinene molecules, particularly present in wood residues and citrus fruit by-products. The utilisation of microbial transformations, along with agro-industrial byproducts, presents a promising approach to extract value from waste materials and enhance the sustainability of the antimicrobial, the fragrance and flavour industry. [ABSTRACT FROM AUTHOR]

Introduction: Despite the increasing number of essential oils being reported on their potential therapeutic effects, some remain relatively unknown on their biological properties. That is the case of the essential oils obtained from copaiba (Copaifera officinalis L.), wintergreen (Gaultheria fragrantissima Wall.), everlasting (Helichrysum italicum (Roth) G.Don) and clove (Syzygium aromaticum (L.) Merr. & L.M.Perry), commonly labelled as being useful on the amelioration of conditions with an inflammatory background.Methods: To further broaden the current knowledge on the four essential oils, commercially available samples were approached on their effects upon a series of mediators that are involved on the inflammatory and oxidative response, both through in vitro cell-free and cell-based assays (5-lipoxygenase activity, lipid peroxidation, free radical and nitric oxide radical scavenging properties or tyrosinase inhibition).Results: The four oils proved to be active at some of the concentrations tested in most of the performed assays. Significant differences were found between the essential oils, S. aromaticum proving to tbe the most active, followed by G. fragrantissima against 5-lipoxygenase (5-LOX) and linoleic acid peroxidation, proving their potential use as antioxidants and anti-inflammatory agents. In fact, the IC50 value of S. aromaticum in the 5-LOX assay was 62.30 μg mL−1. Besides S. aromaticum efficiently scavenged superoxide radicals generated by xanthine/xanthine oxidase, displaying an IC50 value of 135.26 μg mL−1. The essential oil obtained from H. italicum exhibited a significant decrease in the nitric oxide levels on BV-2 cells, showing its potential as a cytoprotective agent against toxic damage. Copaiba oil ranked first as the most potent tyrosinase inhibitor, exhibiting an IC50 98.22 μg mL−1.Conclusion: More studies are needed to describe the essential oils properties, but these results confirm the potential of these essential oils as anti-inflammatory and antioxidant agents.

Antimicrobial resistance is a worldwide problem that urges novel alternatives to treat infections. In attempts to find novel molecules, we assess the antimicrobial potential of seven essential oils (EO) of different plants (Pinus sylvestris, Citrus limon, Origanum vulgare, Cymbopogon martini, Cinnamomum cassia, Melaleuca alternifolia and Eucalyptus globulus) against two multidrug-resistant bacteria species, i.e. Neisseria gonorrhoeae and Streptococcus suis. EOs of P. sylvestris and C. limon revealed higher bactericidal activity (MIC ≤ 0.5 mg/mL) and capacity to rapidly disperse biofilms of several N. gonorrhoeae clinical isolates than other EOs. Examination of biofilms exposed to both EO by electron microscopy revealed a reduction of bacterial aggregates, high production of extracellular vesicles, and alteration of cell integrity. This activity was dose-dependent and was enhanced in DNase I-treated biofilms. Antibiotic susceptibility studies confirmed that both EOs affected the outer membrane permeability, and analysis of EO- susceptibility of an LPS-deficient mutant suggested that both EO target the LPS bilayer. Further analysis revealed that α- and β-pinene and d-limonene, components of both EO, contribute to such activity. EO of C. martini, C. cassia, and O. vulgare exhibited promising antimicrobial activity (MIC ≤ 0.5 mg/mL) against S. suis, but only EO of O. vulgare exhibited a high biofilm dispersal activity, which was also confirmed by electron microscopy studies. To conclude, the EO of P. sylvestris, C. limon and O. vulgare studied in this work exhibit bactericidal and anti-biofilm activities against gonococcus and streptococcus, respectively.

We report a highly selective (100 %) epoxidation of α‐pinene and R‐carvone using an oxygen atom transfer (OAT) reaction facilitated by a dioxo‐Mo complex (Mo(VI)O2Cl2Ln) incorporated into the ligand 5,5'‐dicarboxylate‐2,2'‐bipyridine (bpydc) within a Metal‐Organic Framework (MOF) type UiO‐67. Photo‐stimulated (350 nm) OAT reaction was carried out with oxygen molecular used as the oxidant for 10 h. UiO‐67 was synthesized with a mixture of the ligands 2,2′‐biphenyl‐5,5′‐dicarboxylate (bpdc) and 2,2‐bipyridine‐5,5‐dicarboxylate (bpydc) in different molar ratios (67 : 33, 50 : 50, 70 : 30, 0 : 100 bpdc : bpydc) to promote a higher presence of catalytic sites, i. e., the dioxo‐Mo complex units. Furthermore, a post‐synthetic exchange of Zr for Ti, between 64 : 36 to 78 : 22 Ti : Zr molar ratio, was performed to improve the optical properties of the MOF and promote the photoinduced OAT reaction. The Catalytic system was characterized by FTIR, XRD, 1H NMR, XPS, TGA, N2 adsorption/desorption and UV‐Vis‐DR. The amount of the epoxide monoterpene is proportional to the number of the dioxomolybdenum(VI) units (MoO2) incorporated in the UiO‐67 (Zr/Ti), and the OAT reaction selectivity is due to the absence of the oxygen radicals in the medium of reaction. Besides, The Mo complex exhibited excellent stability after five cycles of use. [ABSTRACT FROM AUTHOR]

Secondary organic aerosol (SOA) is ubiquitous in the atmosphere and plays a pivotal role in climate, air quality, and health. The production of low-volatility dimeric compounds through accretion reactions is a key aspect of SOA formation. However, despite extensive study, the structures and thus the formation mechanisms of dimers in SOA remain largely uncharacterized. In this work, we elucidate the structures of several major dimer esters in SOA from ozonolysis of a-pinene and b-pinene—substantial global SOA sources—through independent synthesis of authentic standards. We show that these dimer esters are formed in the particle phase and propose a mechanism of nucleophilic addition of alcohols to a cyclic acylperoxyhemiacetal. This chemistry likely represents a general pathway to dimeric compounds in ambient SOA. [ABSTRACT FROM AUTHOR]

We present a novel photolytic source of gas-phase NO3 suitable for use in atmospheric chemistry studies that has several advantages over traditional sources that utilize NO2 + O3 reactions and/or thermal dissociation of dinitrogen pentoxide (N2O5). The method generates NO3 via irradiation of aerated aqueous solutions of ceric ammonium nitrate (CAN, (NH4)2Ce(NO3)6) and nitric acid (HNO3) or sodium nitrate (NaNO3). We present experimental and model characterization of the NO3 formation potential of irradiated CAN / HNO3 and CAN / NaNO3 mixtures containing [CAN] = 10 −3 to 1.0 M, [ HNO3 ] = 1.0 to 6.0 M, [ NaNO3 ] = 1.0 to 4.8 M, photon fluxes (I) ranging from 6.9 × 10 14 to 1.0 × 10 16 photons cm -2 s -1 , and irradiation wavelengths ranging from 254 to 421 nm. NO3 mixing ratios ranging from parts per billion to parts per million by volume were achieved using this method. At the CAN solubility limit, maximum [ NO3 ] was achieved using [ HNO3 ] ≈ 3.0 to 6.0 M and UVA radiation (λmax⁡ = 369 nm) in CAN / HNO3 mixtures or [ NaNO3 ] ≥ 1.0 M and UVC radiation (λmax⁡ = 254 nm) in CAN / NaNO3 mixtures. Other reactive nitrogen (NO2 , N2O4 , N2O5 , N2O6 , HNO2 , HNO3 , HNO4) and reactive oxygen (HO2 , H2O2) species obtained from the irradiation of ceric nitrate mixtures were measured using a NOx analyzer and an iodide-adduct high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS). To assess the applicability of the method for studies of NO3 -initiated oxidative aging processes, we generated and measured the chemical composition of oxygenated volatile organic compounds (OVOCs) and secondary organic aerosol (SOA) from the β -pinene + NO3 reaction using a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to the HR-ToF-CIMS. [ABSTRACT FROM AUTHOR]

BACKGROUND: Kaffir lime peel is a food waste which contains good aromatic essential oil and phenolic compounds. Extraction of essential oil from kaffir lime peel is conducted to obtain the extract for using as biological ingredients in various products. After essential oil extraction, kaffir lime peel residue has been remained, and it can be considered as another by‐product. Therefore, it is interesting to evaluate the contents of phenolic compounds in the kaffir lime peel residue to understand the possibility of valorization of kaffir lime peel wastes at a practical level. In this study, extraction of essential oil from fresh kaffir lime peel was conducted by hydrodistillation, and phenolic compounds were extracted from the kaffir lime peel residue by process optimization of an ethanolic extraction method. RESULTS: Through hydrodistillation and gas chromatography–mass spectrometry analysis, essential oil of kaffir lime peel contained terpinene‐4‐ol (19%), β‐pinene (15.8%) and d‐limonene (15.6%) as the major volatile compounds. In extraction of phenolic compounds from kaffir lime peel residue, all investigated parameters had significant linear effects on the yield of phenolic compounds, but no interaction effects among the extraction parameters were observed. Optimal conditions for the extraction were 120 min, 60 °C and 1:20 g mL−1, resulting in phenolic compounds of 8.6 mg GAE g−1 sample. The phenolic compound yield extracted from fresh kaffir lime peel at the optimal conditions was close to that extracted from the kaffir lime peel residue. CONCLUSIONS: Through hydrodistillation, only essential oil was extracted from kaffir lime peel, while phenolic compounds are still remained in the solid residue of the kaffir lime peel at high concentration as the fresh sample. Results of this study are useful for maximizing extraction yield of phenolic compounds from kaffir lime peel. The results of this study also revealed the possibility of maximizing the utilization of kaffir lime peel wastes at the practical stage through extraction of both essential oils and phenolic compounds. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Conventional gas chromatography-mass spectrometry (GC-MS) analysis methods for measuring the concentration of phytoncides in forests are limited because of the need for an extended human presence in forests, the risk of errors, and contamination. To overcome these issues, this study introduces real-time measurement devices and selected ion flow tube mass spectrometry (SIFT-MS) as potential replacements. This study was conducted in the Hongneung Experimental Forest between 19 and 21 November 2019. A correlation analysis and independent samples t-test were performed to compare the GC-MS and SIFT-MS techniques. The diurnal patterns and trends in the phytoncide concentrations analyzed using the GC-MS and SIFT-MS methods were similar, suggesting the potential replacement of GC-MS with SIFT-MS. While both methods revealed similar major components in the daytime nonvolatile organic compounds (NVOCs), with pinenes comprising approximately half of the total percentage, the 24 h SIFT-MS analysis indicated reduced proportions of pinenes and benzaldehyde, along with the detection of more diverse NVOC compounds at night. Additionally, the studies indicated that GC-MS exhibited slightly higher selectivity, resulting in the detection of fewer NVOC compounds with SIFT-MS. The correlation analysis between the microclimate indicators and phytoncide measurement methods revealed differences: GC-MS with a mini pump showed positive correlations with fine dust and industrially derived VOCs, while the 24 h real-time measurements exhibited strong negative correlations. Consequently, while the GC-MS and SIFT-MS methods exhibited both similarities and differences in phytoncide concentrations, an independent samples t-test, confirming no statistically significant differences between the two methods, suggests the suitability of adopting SIFT-MS over GC-MS for phytoncide collection and analysis in forest environments. Nevertheless, this study contributes to the literature by comparing outdoor phytoncide levels using the GC-MS and SIFT-MS methodologies. These findings, which show that the methods are closely aligned, can guide future researchers in considering SIFT-MS equipment for phytoncide studies, offering a more accessible and efficient option with real-time capabilities. [ABSTRACT FROM AUTHOR]

Cumin (Cuminum cyminum L.), an important spice crop belonging to the Apiaceae family is infected by Fusarium oxysporum f. sp. cumini (Foc) to cause wilt disease, one of the most devastating diseases of cumin adversely affects its production. As immune responses of cumin plants against the infection of Foc are not well studied, this research aimed to identify the genes and pathways involved in responses of cumin (cv. GC-2, GC-3, GC-4, and GC-5) to the wilt pathogen. Differential gene expression analysis revealed a total of 2048, 1576, 1987, and 1174 differentially expressed genes (DEGs) in GC-2, GC-3, GC-4, and GC-5, respectively. In the resistant cultivar GC-4 (resistant against Foc), several important transcripts were identified. These included receptors, transcription factors, reactive oxygen species (ROS) generating and scavenging enzymes, non-enzymatic compounds, calcium ion (Ca2+) transporters and receptors, Rproteins, and PR-proteins. The expression of these genes is believed to play crucial roles in conferring resistance against Foc. Gene ontology (GO) analysis of the up-regulated DEGs showed significant enrichment of 19, 91, 227, and 55 biological processes in GC-2, GC-3, GC-4, and GC-5, respectively. Notably, the resistant cultivar GC-4 exhibited enrichment in key GO terms such as 'secondary metabolic process', 'response to reactive oxygen species', 'phenylpropanoid metabolic process', and 'hormone-mediated signaling pathway'. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed the enrichment of 28, 57, 65, and 30 pathways in GC-2, GC-3, GC-4, and GC-5, respectively, focusing on the up-regulated DEGs. The cultivar GC-4 showed enrichment in pathways related to steroid biosynthesis, starch and sucrose metabolism, fatty acid biosynthesis, butanoate metabolism, limonene and pinene degradation, and carotenoid biosynthesis. The activation or upregulation of various genes and pathways associated with stress resistance demonstrated that the resistant cultivar GC-4 displayed enhanced defense mechanisms against Foc. These findings provide valuable insights into the defense responses of cumin that could contribute to the development of cumin cultivars with improved resistance against Foc. [ABSTRACT FROM AUTHOR]

Highly oxygenated molecules (HOM) from the atmospheric oxidation of biogenic volatile organic compounds are important contributors to secondary organic aerosol (SOA). Organic peroxy radicals (RO2) and hydroperoxy radicals (HO2) are key species influencing the HOM product distribution. In laboratory studies experimental requirements often result in overemphasis of RO2 cross-reactions compared to reactions of RO2 with HO2. We analyzed the photochemical formation of HOMs from α-pinene and their potential to contribute to SOA formation under high (≈1/1) and low (≈1/100) HO2/RO2 conditions. As HO2/RO2 > 1 is prevalent in the daytime atmosphere, sufficiently high HO2/RO2 is crucial to mimic atmospheric conditions and to prevent biases by low HO2/RO2 on the HOM product distribution and thus SOA yield. Experiments were performed under steady-state conditions in the new, continuously stirred tank reactor SAPHIR-STAR at Forschungszentrum Jülich. The HO2/RO2 ratio was increased by adding CO, while keeping the OH concentration constant. We determined the HOM's SOA formation potential, considering their fraction remaining in the gas phase after seeding with (NH4)2SO4 aerosol. Increase of HO2/RO2 led to a reduction in SOA formation potential, with the main driver being a ≈60 % reduction in HOM-accretion products. We also observed a shift in HOM-monomer functionalization from carbonyl to hydroperoxide groups. We determined a reduction of the HOM's SOA formation potential by ≈30 % at HO2/RO2≈1/1. Particle phase observations measured an about according decrease in SOA mass and yield. Our study showed that too low HO2/RO2 ratios compared to the atmosphere can lead to an overestimation of SOA yields. [ABSTRACT FROM AUTHOR]

The treatment of a β zeolite with sodium hydroxide solution can partially desilicate the β zeolite, thereby obtaining a mesoporous structure. The isomerization of α-pinene has been studied at 403 K and under atmospheric pressure. The catalytic materials were characterized by XRD, SEM, BET analysis, FT-IR spectroscopy and Py-IR spectroscopy. The results show that the pore structure of the β zeolite can be effectively regulated by the sodium hydroxide solution. The microporous structure of the β zeolite was destroyed. The crystallinity changed, the number of mesopores increased and the amount of acid slightly decreased. The catalyst after alkali treatment was applied to the isomerization reaction of α-pinene. The conversion of α-pinene increased to 96%, and the yield of camphene and limonene reached 67%. It was found that the isomerization reaction of α-pinene on the β zeolite followed the first-order reaction kinetics, and the activation energy of the reaction was 41.58 kJ mol-1. [ABSTRACT FROM AUTHOR]

The investigation of monoterpenes as natural products has gained significant attention in the search for new pharmacological agents due to their ability to exhibit a wide range in biological activities, including antifungal, antibacterial, antioxidant, anticancer, antispasmodic, hypotensive, and vasodilating properties. In vitro and in vivo studies reveal their antidepressant, anxiolytic, and memory-enhancing effects in experimental dementia and Parkinson's disease. Chemical modification of natural substances by conjugation with various synthetic components is a modern method of obtaining new biologically active compounds. The discovery of new potential drugs among monoterpene derivatives is a progressive avenue within experimental pharmacology, offering a promising approach for the therapy of diverse pathological conditions. Biologically active substances such as monoterpenes, for example, borneol, camphor, geraniol, pinene, and thymol, are used to synthesize compounds with analgesic, anti-inflammatory, anticonvulsive, antidepressant, anti-Alzheimer's, antiparkinsonian, antiviral and antibacterial (antituberculosis) properties. Myrtenal is a perspective monoterpenoid with therapeutic potential in various fields of medicine. Its chemical modifications often lead to new or more pronounced biological effects. As an example, the conjugation of myrtenal with the established pharmacophore adamantane enables the augmentation of several of its pivotal properties. Myrtenal–adamantane derivatives exhibited a variety of beneficial characteristics, such as antimicrobial, antifungal, antiviral, anticancer, anxiolytic, and neuroprotective properties, which are worth examining in more detail and at length. [ABSTRACT FROM AUTHOR]

Dipinodiazafluorenes are hybrid nopinane-annelated heterocycles whose molecules include a heterocyclic core of 4,5-diazafluorene fused with fragments of terpene hydrocarbon; they can selectively extract palladium (88−100%), gold (42−96%), and ruthenium (8−19%) by single extraction from acidic aqueous solutions (pH 1.2) containing complex mixtures of 3d elements and noble metals. [ABSTRACT FROM AUTHOR]