Investigation of RH effect on uncommon limonene ozonolysis products and SOA formation in indoor air with real time measurement techniques

Scientific interest in SOA influence on indoor air quality increases since last 20 years. It is well known, that particles of nano-sized diameter pose a threat for human health causing, among others: eye, upper airway irritation, inflammatory response in cells, worsening asthma, hypertension, diabetes, and central nervous dysfunction. Terpenes are reactive VOCs, commonly emitted in indoor air and considered to be SOA precursors by oxidation reactions. The aim of this study was to investigate the relative humidity influence on i) formation of limonene ozonolysis products and ii) SOA formation process - especially the first steps of it. We managed to determine 4 uncommon limonene ozonolysis products (m/z: 43, 83, 99 and 110) appearing in the PTR-TOF-MS mass spectra with the same frequency as well-known formaldehyde, acetone, acetic acid and formic acid. We also detected m/z 75 and m/z 115 formed under dry conditions and m/z 111 and m/z 125 formed under humid conditions. Detected masses formula is proposed with probability >70 % and the probability is derived from the deviation of the exact mass to the measured one and the isotope distribution. SMPS data analysis allowed us to conclude that RH around 40% increases particle mass concentration, regardless initial limonene concentration. Unfortunately, conclusions about RH influence on particle number concentration are inconsistent. Under low initial terpene concentration, RH around 40% decreases particle number concentration. However, for high initial limonene concentration, RH around 40% caused increase in particle number concentration. Obtained results allowed to conclude, that i) RH influences both particle number and particle mass concentration, ii) initial substrate concentration influences SOA formation altering the RH effect, iii) comparison of results and drawing conclusions is difficult due to different experimental protocols in the literature and due to the number of factors influencing SOA formation initiated by terpene oxidation.

Correlations between flavor and fermentation days and changes in quality-related physiochemical characteristics of fermented Aurantii Fructus

The effects of different fermentation times (0, 1, 2, 3, 4, and 5 days) on the physicochemical properties and flavor components of fermented Aurantii Fructus (FAF) were evaluated. Component analysis identified 66 compounds in positive ion mode and 32 compounds in negative ion mode. Flash GC e-nose results showed that propanal, (+)-limonene and n-nonanal may be the flavor characteristic components that distinguish FAF with different fermentation days. Furthermore, we found that the change of total flavonoid content was closely related to colony growth vitality. The total flavonoid content of FAF gradually decreased from 3rd day and then increased from 5th day (3rd day: 0.766 ± 0.123 mg/100 g; 4th day: 0.464 ± 0.001 mg/100 g; 5th day: 0.850 ± 0.192 mg/100 g). Finally, according to antioxidant activity correlation analysis, meranzin, (+)-limonene and total flavonoids were found to be the key substances affecting the fermentation days of FAF. Overall, the optimal fermentation time for FAF was 4 days.

Identification of Terpene Compositions in the Leaves and Inflorescences of Hybrid Cannabis Species Using Headspace-Gas Chromatography/Mass Spectrometry

Although cannabidiol and tetrahydrocannabinol in Cannabis species exert their pharmacological effects via the endocannabinoid system, it is believed that other phytochemicals, particularly terpenes, can modulate therapeutic outcomes through the entourage effect. Therefore, to gain a better understanding of the pharmacological effects of Cannabis, obtaining information on phytochemical compositions, including mono-, di-, and sesqui-terpenes in Cannabis species is essential. Applying a sophisticated analytical method is indispensable. In this study, headspace-gas chromatography/mass spectrometry (HS-GC/MS) was employed to identify major terpenes in the leaves and inflorescences of hybrid Cannabis species. The incubation time and temperature conditions for HS-GC/MS were optimized. This method was successfully applied to the leaves (n = 9) and inflorescences (n = 7) of hybrid Cannabis species. A total of 26 terpenes in Cannabis species were detected, and six major components, such as α-pinene (9.8-2270 μg/g), β-pinene (2.6-930 μg/g), myrcene (0.7-17,400 μg/g), limonene (1.3-300 μg/g), β-caryophyllene (60-3300 μg/g), and α-humulene (40-870 μg/g), were quantified. Each sample showed different terpene compositions, but six major terpenes among all the terpenes detected were consistently found in both the leaves and inflorescences of hybrid Cannabis species. In this study, the six major terpenes' potential in hybrid Cannabis species was evaluated as biomarkers to distinguish hybrid Cannabis species samples. This study contributes to a better understanding of the entourage effect of Cannabis-based botanical drugs.

Essential oil composition and antioxidant activity of citron fruit (Citrus medica var. macrocarpa Risso.) peel as relation to ripening stages

Stages of maturity have decisive roles in determining the quality and quantity of essential oil (EO). In this regard, EO yield and composition and their antioxidant activity of citron fruit at four fruit maturity stages, i.e. the green mature (GM), intermediate (INT), yellow ripe (MAT) and overripe stage (OR) were studied. Obtained results showed significant effect of fruit maturity on most measured properties. The concentration of EO varied between 0.60 and 0.77% (v/w). The highest amount of limonene was 89.39% related to GM stage. The limonene decreased significantly during maturity. The highest antioxidant activity (76.08%) was measured at the OR stage, which is probably due to the presence of specific compounds in the EO and their synergistic effects. The phytochemical behaviors of this citron variety were different as relation to stages of fruit maturity. We can determine the ideal harvest period for maximum bioactive substances by recognizing these actions.

Antimicrobial and anti-aflatoxigenic activities of nanoemulsions based on Achillea millefolium and Crocus sativus flower extracts as green promising agents for food preservatives

BACKGROUND

Although the mechanism of action of nanoemulsion is still unclear, the modern use of nanoemulsions made from natural extracts as antimicrobial and anti-aflatoxigenic agents represents a potential food preservation and a safety target.

METHODS

Two natural nanoemulsion extracts of Crocus sativus (the saffron flower) and Achillea millefolium (the yarrow flower) were produced in the current study using a low-energy method that included carboxymethylcellulose and Arabic gum. The synthesized nanoemulsion was fully identified by different analytical methods. Detection of the volatile content was completed using GC-MS analysis. The antioxidant potential, and phenolic compounds content were analyzed in the extractions. The synthesized nanoemulsions were screened for their antimicrobial potential in addition to their anti-aflatoxigenic activity.

RESULTS

The droplet size of Saffron flowers was finer (121.64 ± 2.18 nm) than yarrow flowers (151.21 ± 1.12 nm). The Zeta potential measurements of the yarrow flower (-16.31 ± 2.54 mV) and the saffron flower (-18.55 ± 2.31 mV) both showed high stability, along with low PDI values (0.34-0.41). The nanoemulsion of yarrow flower revealed 51 compounds using gas chromatography-mass spectrometry (GCMS), with hexanal (16.25%), β-Pinene (7.41%), β-Myrcene (5.24%), D-Limonene (5.58%) and Caryophyllene (4.38%) being the most prevalent. Additionally, 31 compounds were detected in the saffron nanoemulsion, with D-limonene (4.89%), isophorone (12.29%), 4-oxy isophorone (8.19%), and safranal (44.84%) being the most abundant. Compared to the nanoemulsion of the yarrow flower, the saffron nanoemulsion had good antibacterial and antifungal activity. Saffron nanoemulsion inhibited total fungal growth by 69.64-71.90% in a simulated liquid medium and demonstrated the most significant decrease in aflatoxin production. Infected strawberry fruits coated with nanoemulsion extracts exhibited high antimicrobial activity in the form of saffron flower and yarrow flower extract nanoemulsions, which inhibited and/or controlled the growth of Aspergillus fungi. Due to this inhibition, the lag phase was noticeably prolonged, the cell load decreased, and the stability time increased.

CONCLUSION

This study will contribute to expanding the theoretical research and utilization of nanoemulsions as green protective agents in agricultural and food industries for a promising protection from the invasion of some pathogenic bacteria and fungi.

HS-SPME coupled with GC-MS for elucidating differences between the volatile components in wild and cultivated Atractylodes chinensis

INTRODUCTION

Atractylodes chinensis is a Chinese herb that is used in traditional medicine; it contains volatile components that have enormous potential for pharmaceutical, food, and cosmetic applications. The destruction of wild resources demands significant improvement in the quality of artificial cultivation of Atractylodes chinensis. However, little is known about the compositional differences in the volatile substances derived from the wild and cultivated varieties of Atractylodes chinensis.

OBJECTIVES

We aimed to evaluate the specific components of Atractylodes chinensis and analyse the similarities and differences between the volatile components and metabolic pathways in the wild and cultivated varieties.

MATERIAL AND METHODS

Metabolomic analysis using gas chromatography-mass spectrometry (GC-MS) was employed following the extraction of volatile components from Atractylodes chinensis using headspace solid-phase microextraction (HS-SPME).

RESULTS

A total of 167 volatile metabolites were extracted, and 137 substances were matched with NIST and Wiley databases. Among them, 76 compounds exhibited significant differences between the two sources; these mainly included terpenes, aromatics, and esters. KEGG enrichment analysis indicated that the differential metabolites were primarily involved in the biosynthesis of secondary metabolites, terpene biosynthesis, and limonene and pinene degradation; all these pathways have geranyl diphosphate (GDP) as the common link.

CONCLUSION

The total content of volatile substances extracted from wild Atractylodes chinensis was 2.5 times higher than that from the cultured variety; however, each source had different dominant metabolites. This study underscores the necessity for protecting wild Atractylodes chinensis resources, while enhancing the quality of cultivated Atractylodes chinensis.

Geographical variation in the chemical composition, anti-inflammatory activity of the essential oil, micromorphology and histochemistry of Schinus terebinthifolia Raddi

ETHNOPHARMACOLOGICAL RELEVANCE

Schinus terebinthifolia Raddi (Anacardiaceae) is rich in essential oil, distinguished by a predominance of monoterpenes and sesquiterpenes, it being widely used in traditional medicine for the treatment of inflammations.

AIM OF STUDY

This study's objective was to investigate the chemical composition of the essential oil of S. terebinthifolia (EOST) collected in six states of Brazil, evaluate its anti-inflammatory effects in mice, and analyze the histochemistry and micromorphology of leaves and stems.

MATERIALS AND METHODS

Aerial parts of S. terebinthifolia were collected in six states of Brazil, and the essential oil was extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). The histochemistry and micromorphology of leaves and stems were performed using standard reagents, light and field emission scanning electron microscopy, beyond energy-dispersive X-ray spectroscopy. The EOST were evaluated for anti-inflammatory activity and hyperalgesia using the carrageenan-induced paw edema methodology.

RESULTS

The EOST showed variation across the six states in its yield (0.40%-0.86%) and chemical composition: hydrocarbon monoterpenes (28.76%-47.73%), sesquiterpenes, (31.43%-41.76%), oxygenated monoterpenes (14.31%-19.57%), and oxygenated sesquiterpenes (4.87%-14.38%). Both α-pinene and limonene were predominant constituents of essential in five regions, except for one state where α-phellandrene and limonene were the dominant components. A comprehensive description of the leaf and stem micromorphology and histochemistry was performed. In the in vivo testing, all EOST samples exerted antiedematogenic and anti-hyperalgesic effects, when tested in a carrageenan-induced paw inflammation (mechanical and thermal hyperalgesia) model with oral doses of 30 mg/kg.

CONCLUSION

Our results indicate that the EOST samples collected in six Brazilian states differed in their chemical composition but not their anti-inflammatory and antihyperalgesic effects, which was correlated with the synergistic effect of its components, collaborating the etnhopharmacologycal use of this plant due to its an anti-inflammatory effect. Also, micromorphology and histochemistry of leaves and stems presented in this study provide anatomical and microchemical information, which aids species identification.

[Comparison between macroscopic identification and DNA barcoding identification of Amomi Fructus]

This study aims to explore the consistency between macroscopic identification and DNA barcoding identification of Amomi Fructus. With the DNA barcoding identification results, we evaluated the reliability of identifying Amomi Fructus quality by combining macroscopic traits with main volatile chemical components. Thirteen batches of Amomi Fructus samples were collected for identification. Firstly, the morphological and sensory characteristics of each sample were observed and recorded according to the standard in Chinese Pharmacopoeia(2020 edition). The 100-fruit weight, longitudinal diameter, transverse diameter, and longitudinal diameter-to-transverse diameter ratio were measured, which correspond to large, solid, and full kernel representing good quality in the sensory evaluation. The odor value detected by electronic nose and major volatile components(borneol, camphor, limonene, and borneol acetate) correspond to the sensory evaluation of strong odor representing good quality. Secondly, DNA barcoding was employed to identify the 13 batches of samples. Finally, clustering analysis was performed for the main volatile components and macroscopic traits, and the identification results were compared with those of DNA barcoding. Except two batches of samples(No.6 and No.10), the macroscopic identification showed the results consistent with those of DNA barcoding, with an identification rate of 84.62%. The clustering results of the content of four volatile chemical components and macroscopic traits were also consistent with the DNA barcoding identification results. DNA barcoding can verify the results of macroscopic identification and provide a scientific basis for the inheritance and development of macroscopic identification. Moreover, the combination of macroscopic traits and chemical components demonstrates higher accuracy in the quality evaluation of Chinese medicinal materials.

Neutrophil Immunomodulatory Activity of (−)-Borneol, a Major Component of Essential Oils Extracted from Grindelia squarrosa

Grindelia squarrosa (Pursh) Dunal is used in traditional medicine for treating various diseases; however, little is known about the immunomodulatory activity of essential oils from this plant. Thus, we isolated essential oils from the flowers (GEO_Fl) and leaves (GEO_Lv) of G. squarrosa and evaluated the chemical composition and innate immunomodulatory activity of these essential oils. Compositional analysis of these essential oils revealed that the main components were α-pinene (24.7 and 23.2% in GEO_Fl and GEO_Lv, respectively), limonene (10.0 and 14.7%), borneol (23.4 and 16.6%), p-cymen-8-ol (6.1 and 5.8%), β-pinene (4.0 and 3.8%), bornyl acetate (3.0 and 5.1%), trans-pinocarveol (4.2 and 3.7%), spathulenol (3.0 and 2.0%), myrtenol (2.5 and 1.7%), and terpinolene (1.7 and 2.0%). Enantiomer analysis showed that α-pinene, β-pinene, and borneol were present primarily as (−)-enantiomers (100% enantiomeric excess (ee) for (−)-α-pinene and (−)-borneol in both GEO_Fl and GEO_Lv; 82 and 78% ee for (−)-β-pinene in GEO_Fl and GEO_Lv), while limonene was present primarily as the (+)-enantiomer (94 and 96 ee in GEO_Fl and GEO_Lv). Grindelia essential oils activated human neutrophils, resulting in increased [Ca²⁺]_i (EC₅₀ = 22.3 µg/mL for GEO_Fl and 19.4 µg/mL for GEO_Lv). In addition, one of the major enantiomeric components, (−)-borneol, activated human neutrophil [Ca²⁺]_i (EC₅₀ = 28.7 ± 2.6), whereas (+)-borneol was inactive. Since these treatments activated neutrophils, we also evaluated if they were able to down-regulate neutrophil responses to subsequent agonist activation and found that treatment with Grindelia essential oils inhibited activation of these cells by the N-formyl peptide receptor 1 (FPR1) agonist fMLF and the FPR2 agonist WKYMVM. Likewise, (−)-borneol inhibited FPR-agonist-induced Ca²⁺ influx in neutrophils. Grindelia leaf and flower essential oils, as well as (−)-borneol, also inhibited fMLF-induced chemotaxis of human neutrophils (IC₅₀ = 4.1 ± 0.8 µg/mL, 5.0 ± 1.6 µg/mL, and 5.8 ± 1.4 µM, respectively). Thus, we identified (−)-borneol as a novel modulator of human neutrophil function.

Chemical Profiling, Toxicity and Anti-Inflammatory Activities of Essential Oils from Three Grapefruit Cultivars from KwaZulu-Natal in South Africa

The medicinal potential and volatile composition of different parts of three cultivars of grapefruit (Citrus paradisi) were evaluated for their toxicity and anti-inflammatory activities. Fresh leaf and fruit peel were separately isolated by hydrodistillation for 4 h. The essential oils were subjected to GC/GC-MS analysis for chemical profile. Toxicity of the essential oils in mice were evaluated using Lorke’s method, while an anti-inflammatory assay was performed in a rat model using egg albumin-induced oedema. The oils obtained were light yellow in colour, and odour varied from strong citrus smell to mild. Percentage yield of fresh peel oil (0.34–0.57%) was greater than the fresh leaf oil yield (0.21–0.34%). D-limonene (86.70–89.90%) was the major compound identified in the leaf oil, while β-phellandrene (90.00–91.01%) dominated the peel oil. At a dosage level of 5000 mg/kg, none of the oils showed mortality in mice. An anti-inflammatory bioassay revealed that all the oils caused a significant (p < 0.05–0.01) reduction in oedema size when compared to the negative control group throughout the 5 h post induction assessment period. The study reveals that the oils are non-toxic and demonstrate significant anti-inflammatory activity. Our findings suggest that the leaf and peel oils obtained from waste parts of grapefruit plants can be useful as flavouring agents, as well as anti-inflammatory agents.

Minty aroma compounds in red wine: Development of a novel automated HS-SPME-arrow and gas chromatography-tandem mass spectrometry quantification method

A novel automated method was developed for the quantitative determination of nine terpenoids that could contribute to the minty notes of red wine bouquet. The method couples headspace SPME-Arrow extraction with GC-MS/MS analysis. PDMS/DVB fiber was chosen for the extraction and an ionization energy of 30 eV permitted to optimize the analyte detection. The optimal sample preparation consists of a two-fold dilution of the wine sample with addition of 4 g of sodium chloride while the most suitable extraction conditions take place at 50 °C for 1 h. The method shows good linearity, intraday variations between 2 and 25%, interday variations between 7 and 23% and recoveries between 80 and 119%. The method exhibits the required low detection (between 3 and 60 ng/L) and quantification (between 6 ng/L and 200 ng/L) limits. These limits have permitted the quantification of the pool of minty terpenoids in fourteen red Bordeaux wines.

Antioxidant and Anti-Proliferative Activity of Essential Oil and Main Components from Leaves of Aloysia polystachya Harvested in Central Chile

The aim of this study was to determine, first, the chemical composition of Aloysia polystachya (Griseb) Moldenke essential oil, from leaves harvested in central Chile; and second, its antioxidant and cytotoxic activity. Eight compounds were identified via gas chromatography–mass spectrometry (GC–MS) analyses, with the most representative being R-carvone (91.03%), R-limonene (4.10%), and dihydrocarvone (1.07%). For Aloysia polystachya essential oil, antioxidant assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), H₂O₂, ferric reducing antioxidant power (FRAP), and total reactive antioxidant potential (TRAP)) showed good antioxidant activity compared to commercial antioxidant controls; and anti-proliferative assays against three human cancer cell lines (colon, HT-29; prostate, PC-3; and breast, MCF-7) determined an IC₅₀ of 5.85, 6.74, and 9.53 µg/mL, and selectivity indices of 4.75, 4.12, and 2.92 for HT-29, PC-3, and MCF-7, respectively. We also report on assays with CCD 841 CoN (colon epithelial). Overall, results from this study may represent, in the near future, developments for natural-based cancer treatments.

Breath Biopsy Assessment of Liver Disease Using an Exogenous Volatile Organic Compound-Toward Improved Detection of Liver Impairment

INTRODUCTION

Liver cirrhosis and its complication - hepatocellular carcinoma (HCC) - have been associated with increased exhaled limonene. It is currently unclear whether this increase is more strongly associated with the presence of HCC or with the severity of liver dysfunction.

METHODS

We compared the exhaled breath of 40 controls, 32 cirrhotic patients, and 12 cirrhotic patients with HCC using the Breath Biopsy platform. Breath samples were analyzed by thermal desorption-gas chromatography-mass spectrometry. Limonene levels were compared between the groups and correlated to bilirubin, albumin, prothrombin time international normalized ratio, and alanine aminotransferase.

RESULTS

Breath limonene concentration was significantly elevated in subjects with cirrhosis-induced HCC (M: 82.1 ng/L, interquartile range [IQR]: 16.33-199.32 ng/L) and cirrhosis (M: 32.6 ng/L, IQR: 6.55-123.07 ng/L) compared with controls (M: 6.2 ng/L, IQR: 2.62-9.57 ng/L) (P value = 0.0005 and 0.0001, respectively) with no significant difference between 2 diseased groups (P value = 0.37). Levels of exhaled limonene correlated with serum bilirubin (R = 0.25, P value = 0.0016, r = 0.51), albumin (R = 0.58, P value = 5.3e-8, r = -0.76), and international normalized ratio (R = 0.29, P value = 0.0003, r = 0.51), but not with alanine aminotransferase (R = 0.01, P value = 0.36, r = 0.19).

DISCUSSION

Exhaled limonene levels are primarily affected by the presence of cirrhosis through reduced liver functional capacity, as indicated by limonene correlation with blood metrics of impaired hepatic clearance and protein synthesis capacity, without further alterations observed in subjects with HCC. This suggests that exhaled limonene is a potential non-invasive marker of liver metabolic capacity (see Visual abstract, Supplementary Digital Content 1, http://links.lww.com/CTG/A388).

Vitamin E Acetate in Bronchoalveolar-Lavage Fluid Associated with EVALI

BACKGROUND

The causative agents for the current national outbreak of electronic-cigarette, or vaping, product use-associated lung injury (EVALI) have not been established. Detection of toxicants in bronchoalveolar-lavage (BAL) fluid from patients with EVALI can provide direct information on exposure within the lung.

METHODS

BAL fluids were collected from 51 patients with EVALI in 16 states and from 99 healthy participants who were part of an ongoing study of smoking involving nonsmokers, exclusive users of e-cigarettes or vaping products, and exclusive cigarette smokers that was initiated in 2015. Using the BAL fluid, we performed isotope dilution mass spectrometry to measure several priority toxicants: vitamin E acetate, plant oils, medium-chain triglyceride oil, coconut oil, petroleum distillates, and diluent terpenes.

RESULTS

State and local health departments assigned EVALI case status as confirmed for 25 patients and as probable for 26 patients. Vitamin E acetate was identified in BAL fluid obtained from 48 of 51 case patients (94%) in 16 states but not in such fluid obtained from the healthy comparator group. No other priority toxicants were found in BAL fluid from the case patients or the comparator group, except for coconut oil and limonene, which were found in 1 patient each. Among the case patients for whom laboratory or epidemiologic data were available, 47 of 50 (94%) had detectable tetrahydrocannabinol (THC) or its metabolites in BAL fluid or had reported vaping THC products in the 90 days before the onset of illness. Nicotine or its metabolites were detected in 30 of 47 of the case patients (64%).

CONCLUSIONS

Vitamin E acetate was associated with EVALI in a convenience sample of 51 patients in 16 states across the United States. (Funded by the National Cancer Institute and others.).

Unraveling the selective antibacterial activity and chemical composition of citrus essential oils

Post-weaning diarrhea (PWD) is an often disease affecting piglets. It is caused mainly by enterotoxigenic Escherichia coli (ETEC) colonization in pig gut. Antibiotics has been used to prevent, combat and control PWD and its negative impact on the productivity of pig breeding sector. Nonetheless, antibiotics due to their wide antibacterial spectrum also can reach beneficial gut bacteria, such as Lactobacillus. Lately, essential oils (EOs) have emerged as a potential alternative to using antibiotics in animal breeding because of their effect on bacterial growth. Commonly, citrus EOs are by-products of food industry and the availability of these EOs in the worldwide market is huge. Thus, six commercials citrus EOs were evaluated on ETEC strains, as model of pathogenic bacteria, and on Lactobacillus species, as models of beneficial bacteria. In overall, citrus EOs exhibited a selective antibacterial activity with higher effect on pathogenic bacteria (ETECs) than beneficial bacteria (Lactobacillus). Brazilian orange terpenes (BOT) oil presented the highest selective performance and caused higher disturbances on the normal growth kinetic of ETEC than on Lactobacillus rhamnosus. The action was dose-dependent on the maximal culture density (A) and the lag phase duration (λ) of the ETEC. The highest sub-inhibitory concentration (0.925 mg/mL) extended the λ duration to ETEC eight times (14.6 h) and reduced A in 55.9%. For L. rhamnosus, the λ duration was only extended 1.6 times. Despite the fact that limonene was detected as the major compound, the selective antibacterial activity of the citrus EOs could not be exclusively attributed to limonene since the presence of minor compounds could be implicated in conferring this feature.

Indoor boundary layer chemistry modeling

Ozone (O₃ ) chemistry is thought to dominate the oxidation of indoor surfaces. We consider the hypothesis that reactions taking place within indoor boundary layers result in greater than anticipated hydroxyl radical (OH) deposition rates. We develop models that account for boundary layer mass-transfer phenomena, O₃ -terpene chemistry and OH formation, removal, and deposition; we solve these analytically and by applying numerical methods. For an O₃ -limonene system, we find that OH flux to a surface with an O₃ reaction probability of 10^-8 is 4.3 × 10^-5 molec/(cm² s) which is about 10 times greater than predicted by a traditional boundary layer theory. At very low air exchange rates the OH surface flux can be as much as 10% of that for O₃ . This effect becomes less pronounced for more O₃ -reactive surfaces. Turbulence intensity does not strongly influence the OH concentration gradient except for surfaces with an O₃ reaction probability >10^-4 . Although the O₃ flux dominates OH flux under most conditions, OH flux can be responsible for as much as 10% of total oxidant uptake to otherwise low-reactivity surfaces. Further, OH chemistry differs from that for ozone; therefore, its deposition is important in understanding the chemical evolution of some indoor surfaces and surface films.

Characterization of Volatile Compounds in Four Different Rhododendron Flowers by GC×GC-QTOFMS

Volatile compounds in flowers of Rhododendron delavayi, R. agastum, R. annae, and R. irroratum were analyzed using comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC) coupled with high-resolution quadrupole time-of-flight mass spectrometry (QTOFMS). A significantly increased number of compounds was separated by GC×GC compared to conventional one-dimensional GC (1DGC), allowing more comprehensive understanding of the volatile composition of Rhododendron flowers. In total, 129 volatile compounds were detected and quantified. Among them, hexanal, limonene, benzeneacetaldehyde, 2-nonen-1-ol, phenylethyl alcohol, citronellal, isopulegol, 3,5-dimethoxytoluene, and pyridine are the main compounds with different content levels in all flower samples. 1,2,3-trimethoxy-5-methyl-benzene exhibits significantly higher content in R. irroratum compared to in the other three species, while isopulegol is only found in R. irroratum and R. agastum.

Chemical profiling, cytotoxicity and phytotoxicity of foliar volatiles of Hyptis suaveolens

In the present study, the essential oil (EO) of Hyptis suaveolens has been explored for the first time for its phytotoxic and cytotoxic activities. The phytotoxic activity was assessed against rice (Oryza sativa) and its major troublesome weed, Echinochloa crus-galli, under laboratory and screenhouse conditions. GC-MS analysis revealed EO to be monoterpenoid (~ 79% monoterpenes) in nature with α-phellandrene (22.8%), α-pinene (10.1%) and limonene (8.5%) as the major chemical constituents. The laboratory bioassay showed a complete growth inhibitory effect of EO (≥ 2 mg mL^-1) towards the germination and seedling growth of E. crus-galli. However, the inhibitory effect on rice was much less (~40% inhibition). EO caused visible injury, reduction in chlorophyll content, cell viability and ultimately led to complete wilting of E. crus-galli plants. In addition, EO altered the cell division in the meristematic cells of Allium cepa as depicted by ~63% decrease in mitotic index. EO exposure induced several aberrations at chromosomal (c-mitosis, anaphase bridges, chromosomal breakage, vagrant chromosomes, and sticky chromosomes) and cytological level (cytoplasm destruction, peripheral nuclei, and bi-nucleate cells). The present study concludes that H. suaveolens EO possesses phytotoxic activity due to its mito-depressive activity, and could serve as a natural herbicide under sustainable agricultural practices.

Traceability of Functional Volatile Compounds Generated on Inoculated Cocoa Fermentation and Its Potential Health Benefits

Microbial communities are responsible for the unique functional properties of chocolate. During microbial growth, several antimicrobial and antioxidant metabolites are produced and can influence human wellbeing. In the last decades, the use of starter cultures in cocoa fermentation has been pushed to improve nutritional value, quality, and the overall product safety. However, it must be noted that unpredictable changes in cocoa flavor have been reported between the different strains from the same species used as a starter, causing a loss of desirable notes and flavors. Thus, the importance of an accurate selection of the starter cultures based on the biogenic effect to complement and optimize chocolate quality has become a major interest for the chocolate industry. This paper aimed to review the microbial communities identified from spontaneous cocoa fermentations and focused on the yeast starter strains used in cocoa beans and their sensorial and flavor profile. The potential compounds that could have health-promoting benefits like limonene, benzaldehyde, 2-phenylethanol, 2-methylbutanal, phenylacetaldehyde, and 2-phenylethyl acetate were also evaluated as their presence remained constant after roasting. Further research is needed to highlight the future perspectives of microbial volatile compounds as biomarkers to warrant food quality and safety.

Piper nigrum Oil - Determination of Selected Terpenes for Quality Evaluation

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

Is residential ambient air limonene associated with asthma? Findings from the Canadian Health Measures Survey

Asthma is a common chronic disease. Exposure to limonene is commonplace because it may be used in the manufacture of personal care products and household cleaners. We investigated the influence of limonene on asthma in a population-based sample of approximately 3000 Canadians. During the Canada Health Measures Survey, carried out between 2012 and 2013, participants were asked if they wheezed or had a diagnosis of asthma, and underwent spirometry and measurement of the fraction of exhaled nitric oxide (FeNO). These variables were tested for an association with limonene concentrations measured in their household air samples, using linear regression analysis A 100% increase in air limonene concentration was associated with an approximate 17% adjusted relative increase wheezing with an odds ratio of 1.17 (95%CI 1.16, 1.18). The percent change in FeNO for a 100% increase in limonene was twice as large for children, 2.89% (95% CI 1.88, 4.43) compared to adults, 1.44% (95%CI 1.16, 1.79). Among boys, the odds ratio was 1.50 (95%CI 1.48, 1.52) between a 100% increase in limonene and a diagnosis of asthma. This study provides evidence that household exposure to limonene may increase the prevalence of asthma in the general population.

A Comparative Study on Hemp (Cannabis sativa) Essential Oil Extraction Using Traditional and Advanced Techniques

A comparative study of Cannabis sativa (Hemp) essential constituents obtained by using Supercritical Fluid Extraction (SCFE), Steam Distillation (SD) and Hydrodistillation (HD) is presented here. The optimized extraction temperatures were 130，110 and 50 ℃ for hydrodistillation, steam distillation and supercritical fluid extraction respectively. The essential oil of C. sativa was analyzed by using Gas chromatography mass spectrometry (GC-MS). A total of 33, 30 and 31 components have been identified in HD, SD and SCFE respectively. Yield of essential oil using SCFE (0.039%) was more than HD (0.025%) and SD (0.035%) extraction respectively. The main component of sesquiterpenes obtained by hydrodistillation at 130 ℃ with their percentages included caryophyllene (40.58%), trans-α-bergamotene (5.41%), humulene (10.97%), cis-β-farnesene (8.53%) and monoterpenes included α-pinene (2.13%), d-limonene (6.46%), p-cymol (0.65%) and cineole (2.58%) respectively. The main component of sesquiterpenes obtained by SD steam distillation at 110 ℃ including caryophyllene (38.60%) trans-α-bergamotene (4.22%), humulene (10.26%), cis-β-farnesene (6.67%) and monoterpenes included α-pinene (3.21%), d-limonene (7.07%), p-cymol (2.59%) and cineole (3.88%) whereas the more percentages of major components were obtained by SCFE at 50 ℃ included caryophyllene (44.31%), trans-α-bergamotene (6.79%), humulene (11.97%) cis-β-farnesene (9.71%) and monoterpenes included α-pinene (0.45%), d-limonene (2.13%) p-cymol (0.19%) and cineole (1.38 %) respectively. We found yield/efficiency, chemical composition, quality of the essential oils by supercritical fluid extraction superior in terms of modern, green, saving energy and a rapid approach as compared to traditional techniques.