An Effective and Promising Strategy for Plant Protection: Synthesis of L-Carvone-Based Thiazolinone-Hydrazone/Nanochitosan Complexes with Antifungal Activity and Sustained Releasing Performance.

The development of novel natural product-derived nano-pesticide systems with loading capacity and sustained releasing performance of bioactive compounds is considered an effective and promising plant protection strategy. In this work, 25 L-carvone-based thiazolinone-hydrazone compounds 4a~4y were synthesized by the multi-step modification of L-carvone and structurally confirmed. Compound 4h was found to show favorable and broad-spectrum antifungal activity through the in vitro antifungal activity evaluation of compounds 4a~4y against eight phytopathogenic fungi. Thus, it could serve as a leading compound for new antifungal agents in agriculture. Moreover, the L-carvone-based nanochitosan carrier 7 bearing the 1,3,4-thiadiazole-amide group was rationally designed for the loading and sustained releasing applications of compound 4h, synthesized, and characterized. It was proven that carrier 7 had good thermal stability below 200 °C, dispersed well in the aqueous phase to form numerous nanoparticles with a size of~20 nm, and exhibited an unconsolidated and multi-aperture micro-structure. Finally, L-carvone-based thiazolinone-hydrazone/nanochitosan complexes were fabricated and investigated for their sustained releasing behaviors. Among them, complex 7/4h-2 with a well-distributed, compact, and columnar micro-structure displayed the highest encapsulation efficiency and desirable sustained releasing property for compound 4h and thus showed great potential as an antifungal nano-pesticide for further studies.

Volatile compositions and glandular trichomes of Zataria multiflora in different phenological stages under normal and drought stress conditions.

BACKGROUND: Zataria multiflora Boiss. is a medicinal and aromatic plant from the Lamiaceae family. It is extensively used in Iranian traditional medicine, mostly as a replacement for Thyme species. This study was focused on the analysis of chemical composition and the distribution and types of trichomes of Z. multiflora grown under different conditions. Equilibrium headspace analysis in combination with GC-FID-MS was used to identify volatile compounds released by aerial parts of Z. multiflora in development stages of 50 and 100% flowering under normal and drought-stress conditions. RESULTS: The main constituents were p-cymene (20.06-27.40%), γ-terpinene (12.44-16.93%), and α-pinene (6.91-16.58%) and thymol (8.52-9.99%). The highest content of p-cymene (27.40%) and thymol (9.99%) was observed in the 50% flowering stage at the 90% field capacity, while the maximum γ-terpinene (16.93%) content was recorded in the 100% flowering stage under normal conditions. Using the SEM method, it was found that peltate glandular and non-glandular trichomes are distributed on the surface of the leaf, stem, and outer side of the calyx. However, capitate trichomes only are detected on the stem and calyx in the 100% flowering and beginning of blooming stages, respectively. The type and structure of trichomes do not vary in different development stages, but they differ in density. The highest number of leaf peltate glandular trichomes was observed in the vegetative and beginning of blooming stages at 50% and 90% field capacity, respectively. Non-glandular trichomes of the stem were observed with high density in both normal and stress conditions, which are more densely in 90% field capacity. CONCLUSIONS: Since this plant has strong potential to be used in the food and pharmacological industries, this study provides valuable information for its cultivation and harvesting at specific phenological stages, depending on desired compounds and their concentrations.

Neuroprotective Effects of [Formula: see text]-Terpinene in Rats with Acute Cerebral Ischemia: Modulation of Inflammation, Apoptosis, and Oxidation.

The study aimed to assess 𝛾-Terpinene's (𝛾-TER) neuroprotective potential in acute cerebral ischemia, characterized by reduced cerebral blood flow in rats. Middle cerebral artery occlusion (MCAO), a standard method for inducing cerebral ischemia, was employed in male Wistar rats. 𝛾-TER at varying doses (5, 10, and 15 mg/kg) were intraperitoneally administered during reperfusion onset. Neurological outcomes, cerebral infarct size, edema, and enzymatic activities (SOD, GPx, and catalase) in the brain were evaluated using diverse techniques. The study examined gene expression and pathways associated with neuroinflammation and apoptosis using Cytoscape software, identifying the top 10 genes involved. Pro-inflammatory and pro-apoptotic factors were assessed through real-time PCR and ELISA, while apoptotic cell rates were measured using the TUNEL and Flow cytometry assay. Immunohistochemistry assessed apoptosis-related proteins like Bax and bcl-2 in the ischemic area. 𝛾-TER, particularly at doses of 10 and 15 mg/kg, significantly reduced neurological deficits and cerebral infarction size. The 15 mg/kg dose mitigated TNF-α, IL-1ß, Bax, and caspase-3 gene and protein levels in the cortex, hippocampus, and striatum compared to controls. Furthermore, Bcl-2 levels increased in these regions. 𝛾-TER show cased neuroprotective effects by suppressing inflammation, apoptosis, and oxidation. In conclusion, 𝛾-TER, possessing natural anti-inflammatory and anti-apoptotic properties, shields the brain against ischemic damage by reducing infarction, edema, oxidative stress, and inflammation. It modulates the expression of crucial genes and proteins associated with apoptosis in diverse brain regions. These findings position 𝛾-TER as a potential therapeutic agent for ischemic stroke.

Multi-targeted effects of D-carvone against Non-Small Cell Lung Cancer (NSCLC): A network pharmacology-based study.

Non-small cell lung cancer (NSCLC) is a complex malignancy with a high degree of heterogeneity, representing approximately 85% of all lung cancer cases. The treatment landscape for NSCLC has been revolutionised by incorporating targeted and immunotherapies; however, novel therapeutic modalities are consistently needed to enhance the treatment outcomes. Indeed, alternative anti-cancer therapies involving natural products have drawn the attention of clinicians and scientists owing to their remarkable chemopreventive potential, often displaying minimal toxicity. D-carvone (CN) is one such natural product that has exhibited numerous promising therapeutic benefits, yet its efficacy against NSCLC remains enigmatic. In the present study, network pharmacological studies and molecular docking in conjunction with in-vitro validation were used to elucidate the underlying mechanism of action of CN comprehensively. Different databases revealed a total of 77 putative anti-NSCLC targets of CN. The identified core targets were utilised to construct a "Compound- Target- Disease" network by Cytoscape (v3.9.0). Further analysis identified 5 core/ hub targets of CN including JAK2, ERK1, ESR1, GSK3B and HSP90AA1. Molecular docking indicated a strong binding interaction of the compound with these core targets. Also, Gene Ontology and KEGG analysis validated the involvement of multiple biological processes. Additionally, CN significantly inhibited cell proliferation, clonogenicity, and wound healing potential while promoting apoptosis in a dose-dependent manner in H1299 and A549 cell lines as examined by flow cytometry, morphological assessment, and western blotting. In conclusion, this study delineates the therapeutic effects of CN on NSCLC, thus highlighting CN as a putative drug candidate for further analysis.

Bioactivities and Synergistic Effect of Elsholtzia ciliata Essential Oil and Its Main Components against Lasioderma serricorne.

Investigations have shown that storage bugs seriously harm grains during storage. In the interim, essential oils (EOs) have been proven to be a good botanical pesticide. The anti-Lasioderma serricorne properties of Elsholtzia ciliata essential oil, which was obtained by steam distillation, were evaluated using DL-limonene, carvone, and their two optical isomer components using contact, repelling, and fumigation techniques. Simultaneously, the fumigation, contact, and repellent activities of carvone and its two optical isomers mixed with DL-limonene against L. serruricorne were evaluated. The results showed that E. ciliata, its main components (R-carvone, DL-limonene), and S-carvone exhibited both fumigations (LC50 = 14.47, 4.42, 20.9 and 3.78 mg/L) and contact (LD50 = 7.31, 4.03, 28.62 and 5.63 µg/adult) activity against L.serricorne. A binary mixture (1:1) of R-carvone and DL-limonene displayed an obvious synergistic effect. A binary mixture (1:1) of carvone and its two optical isomers exhibited an obvious synergistic effect, too. Furthermore, the repellent activity of the EO, carvone, and its two optical isomers, DL-limonene, and a combination of them varied. To stop insect damage during storage, E. ciliata and its components can be utilized as bio-insecticides.

Chemical Characterization of the Essential Oil Compositions of Mentha spicata and M. longifolia ssp. cyprica from the Mediterranean Basin and Multivariate Statistical Analyses.

This present study aims to characterize the essential oil compositions of the aerial parts of M. spicata L. and endemic M. longifolia ssp. cyprica (Heinr. Braun) Harley by using GC-FID and GC/MS analyses simultaneously. In addition, it aims to perform multivariate statistical analysis by comparing with the existing literature, emphasizing the literature published within the last two decades, conducted on both species growing within the Mediterranean Basin. The major essential oil components of M. spicata were determined as carvone (67.8%) and limonene (10.6%), while the major compounds of M. longifolia ssp. cyprica essential oil were pulegone (64.8%) and 1,8-cineole (10.0%). As a result of statistical analysis, three clades were determined for M. spicata: a carvone-rich chemotype, a carvone/trans-carveol chemotype, and a pulegone/menthone chemotype, with the present study result belonging to the carvone-rich chemotype. Carvone was a primary determinant of chemotype, along with menthone, pulegone, and trans-carveol. In M. longifolia, the primary determinants of chemotype were identified as pulegone and menthone, with three chemotype clades being pulegone-rich, combined menthone/pulegone, and combined menthone/pulegone with caryophyllene enrichment. The primary determinants of chemotype were menthone, pulegone, and caryophyllene. The present study result belongs to pulegone-rich chemotype.

Comparison of Approaches for Authentication of Commercial Terpinen-4-ol-type Tea Tree Oils Using Chiral GC/MS.

A global demand for tea tree oil (TTO) has resulted in increased adulteration in commercial products. In this study, we use a novel enantiomeric gas chromatography mass spectrometry method for chiral analysis of key terpenes ((±)-terpinen-4-ol, (±)-α-terpineol, and (±)-limonene) and quantification of components present at >0.01% to test different methods of identifying adulterated TTO. Data from authentic Australian (n = 88) and oxidized (n = 12) TTO samples of known provenance were consistent with recommended ranges in ISO 4730:2017 and previously published enantiomeric ratios, with p-cymene identified as the major marker of TTO oxidation. The 15 ISO 4730:2017 constituents comprised between 84.5 and 89.8% of the total ion chromatogram (TIC) peak area. An additional 53 peaks were detected in all samples (7.3-11.0% of TIC peak area), while an additional 43 peaks were detected in between 0 and 99% (0.15-2.0% of the TIC peak area). Analysis of nine commercial samples demonstrated that comparison to the ISO 4730:2017 standard does not always identify adulterated TTO samples. While statistical analysis of minor components in TTO did identify two commercial samples that differed from authentic TTO, the (+)-enantiomer percentages for limonene, terpinen-4-ol, and α-terpineol provided clearer evidence that these samples were adulterated. Thus, straightforward identification of unadulterated and unoxidized TTO could be based on analysis of appropriate enantiomeric ratios and quantitation of the p-cymene percentage.

Effectively α-Terpineol Suppresses Glioblastoma Aggressive Behavior and Downregulates KDELC2 Expression.

BACKGROUND: Glioblastoma (GBM) is notorious for the aggressive behaviors and easily results in chemo-resistance. Studies have shown that the use of herbal medicines as treatments for GBM as limited by the blood-brain barrier (BBB) and glioma stem cells. PURPOSE: The aim of this study was to investigate the relationship between GBM suppression and α-terpineol, the monoterpenoid alcohol derived from Eucalyptus glubulus and Pinus merkusii. STUDY DESIGN: Using serial in-vitro and in-vivo studies to confirm the mechanism of α-terpineol on down-regulating GBM development. METHODS: The 3-[4,5-dimethylthiazol-2-yl)]-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate IC50 of α-terpineol to inhibit GBM cell survival. In order to evaluate the impact of GBM aggressive behaviors by α-terpineol, the analysis of cell migration, invasion and colony formation were implemented. In addition, the ability of tumor spheres and WB of CD44 and OCT3/4 were evaluated under the impression of α-terpineol decreased GBM stemness. The regulation of neoangiogenesis by α-terpineol via the WB of angiogenic factors and human umbilical vein endothelial cells (HUVEC) tube assay. To survey the decided factors of α-terpineol downregulating GBM chemoresistance depended on the impact of O6-methylguanine-DNA methyltransferase (MGMT) expression and autophagy-related factors activation. Additionally, WB and quantitative real-time polymerase chain reaction (qRT/PCR) of KDEL (Lys-Asp-Glu-Leu) containing 2 (KDELC2), endoplasmic reticulum (ER) stress, phosphoinositide 3-kinase (PI3k), mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) cascade signaling factors were examined to explore the mechanism of α-terpineol inhibiting GBM viability. Finally, the orthotopic GBM mouse model was applied to prove the efficacy and toxicity of α-terpineol on regulating GBM survival. RESULTS: α-terpineol significantly suppressed GBM growth, migration, invasion, angiogenesis and temozolomide (TMZ) resistance. Furthermore, α-terpineol specifically targeted KDELC2 to downregulate Notch and PI3k/mTOR/MAPK signaling pathway. Finally, we also demonstrated that α-terpineol could penetrate the BBB to inhibit GBM proliferation, which resulted in reduced cytotoxicity to vital organs. CONCLUSION: Compared to published literatures, we firstly proved α-terpineol possessed the capability to inhibit GBM through various mechanisms and potentially decreased the occurrence of chemoresistance, making it a promising alternative therapeutic option for GBM in the future.

Composition and antimicrobial activity of Rosmarinus officinalis L. and Artemisia monosperma L. leaf essential oils and methanolic extracts from plants grown in normal and saline habitats in Egypt.

The present work aimed to investigate the effect of salinity in natural habitats in Egypt on the main secondary metabolites of Rosmarinus officinalis L. and Artemisia monosperma L. plants compared to plants grown at normal conditions. Plants grown under salinity were collected from Egyptian Western Coastal region habitats irrigated with underground water. Results showed that salinity increased the essential oil percentage of R. officinalis L. by 52.7% and A. monosperma L by 0.29% in addition to the total phenolics and flavonoids content in dry leaves compared to control plants. GC/MS analysis of rosemary essential oils revealed that salinity decreased the amount of some major oil monoterpenes component as verbenone, with a slight effect on 1,8 cineole and increased Camphor, endo- Boreneol, and linalool in addition to the appearance of new specific components such as Chrysanthenone monoterpene ketone and Caryophyllene sesquiterpene, while, in the case of Artemisia, the GC/MS showed that Artemisia ketone, Camphor, ß -phellandrene monoterpenes andα-Bisabolol sesquiterpenewere the major oil components; salinity decreased Camphor and ß -phellandrene content and increased artemisia ketone and α-Bisabolol oil content. About 11 new oil constituents were detected such as ( +)-2-Bornanone and Sesquisabinene hydrate. Mineral ions (N, K+, Ca+2, P, and Mg+2) uptake by R. officinalis and A. monosperma decreased in plants grown under salinity, while Na content increased compared to corresponding controls. Results demonstrated that both plants could tolerate the high salinity level in natural Western Coastal region soil which promoted more production of valuable secondary metabolites. The antimicrobial effect of R. officinalis L. and A. monosperma L. leaf methanolic extracts, results showed that R. officinalis extracts had an inhibitory response against all tested gram-positive and negative bacteria, in addition to the yeast (Candida albicans), whereas there was no any inhibitory effect concerning A. monosperma L extract on the tested species.

Reprogramming of arachidonic acid metabolism using α-terpineol to alleviate asthma: insights from metabolomics.

Asthma is a chronic inflammatory disorder in airways with typical pathologic features of airway inflammation and mucus hypersecretion. α-Terpineol is a monocyclic terpene found in many natural plants and foods. It has been reported to possess a wide range of pharmacological activities including anti-inflammatory and expectorant effects. However, the role of α-terpineol in asthma and its potential protective mechanism have not been well elucidated. This study is designed to investigate the pharmacological effect and mechanism of α-terpineol on asthmatic mice using the metabolomics platform. A murine model of asthma was established using ovalbumin (OVA) sensitization and then challenged for one week. The leukocyte count and inflammatory cytokines in the bronchoalveolar lavage fluid (BALF), lung histopathology, inflammatory  infiltrate and mucus secretion were evaluated. An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based metabolomics study was performed on lung tissues and serum to explore endogenous small molecule metabolites affected by α-terpineol in asthmatic mice. After α-terpineol treatment, leukocyte count, inflammatory cytokines in the BALF, and peribronchial inflammation infiltration were significantly downregulated. Goblet cell hyperplasia and mucus secretion were attenuated, with the level of Muc5ac in BALF decreased. These results proved the protective effect of α-terpineol against airway inflammation, mucus hypersecretion and Th1/Th2 immune imbalance. To further investigate the underlying mechanisms of α-terpineol in asthma treatment, UPLC-MS/MS-based metabolomics analysis was performed. 26 and 15 identified significant differential metabolites were found in the lung tissues and serum of the control, model and α-terpineol groups, respectively. Based on the above differential metabolites, enrichment analysis showed that arachidonic acid (AA) metabolism was reprogrammed in both mouse lung tissues and serum. 5-Lipoxygenase (5-LOX) and cysteinyl leukotrienes (CysLTs) are the key enzyme and the end product of AA metabolism, respectively. In-depth studies have shown that pretreatment with α-terpineol can alleviate asthma by decreasing the AA level, downregulating the expression of 5-LOX and reducing the accumulation of CysLTs in mouse lung tissues. In summary, this study demonstrates that α-terpineol is a potential agent that can prevent asthma via regulating disordered AA metabolism.

Exogenous methyl jasmonate treatment induced the transcriptional responses and accumulation of volatile terpenoids in Oenanthe javanica (Blume) DC.

Water dropwort is favored by consumers for its unique flavor and medicinal value. Terpenoids were identified as the main volatile compounds related to its flavor. In this study, water dropwort was treated with different concentrations of exogenous methyl jasmonate (MeJA). The contents of volatile terpenoids were determined under various MeJA treatments. The results indicated that 0.1 mM of MeJA most effectively promoted the biosynthesis of flavor-related terpenoids in water dropwort. Terpinolene accounted the highest proportion among terpene compounds in water dropwort. The contents of jasmonates in water dropwort were also increased after exogenous MeJA treatments. Transcriptome analysis indicated that DEGs involved in the terpenoid biosynthesis pathway were upregulated. The TPS family was identified from water dropwort, and the expression levels of Oj0473630, Oj0287510 and Oj0240400 genes in TPS-b subfamily were consistent with the changes of terpene contents under MeJA treatments. Oj0473630 was cloned from the water dropwort and designated as OjTPS3, which is predicted to be related to the biosynthesis of terpinolene in water dropwort. Subcellular localization indicated that OjTPS3 protein was localized in chloroplast. Protein purification and enzyme activity of OjTPS3 protein were conducted. The results showed that the purified OjTPS3 protein catalyzed the biosynthesis of terpinolene by using geranyl diphosphate (GPP) as substrate in vitro. This study will facilitate to further understand the molecular mechanism of terpenoid biosynthesis and provide a strategy to improve the flavor of water dropwort.

Total Synthesis of a TNBC-Selective Cytotoxic Bromo Nor-eremophilane, PC-A, and Its Preliminary Structure-Activity Relationships.

PC-A (1), a bromo nor-eremophilane, showed selective antiproliferative activity against a triple-negative breast cancer (TNBC) cell line. This unique activity prompted us to establish a total synthesis to facilitate a structure-activity relationship (SAR) study and selectivity optimization. An enantioselective first total synthesis of 1 was achieved starting from (R)-carvone through a side chain extension with a Mukaiyama aldol reaction and decalin construction. The synthesized decalin derivatives and debromo PC-A (2) were evaluated for antiproliferative activity against five human tumor cell lines, including TNBC, to assess preliminary SAR correlations.

α­Phellandrene enhances the apoptosis of HT­29 cells induced by 5­fluorouracil by modulating the mitochondria­dependent pathway.

α­Phellandrene (α­PA), a natural constituent of herbs, inhibits cancer cell viability and proliferation. 5­Fluorouracil (5­FU) is a frequently utilized chemotherapeutic medicine for the treatment of colon cancer, which works by triggering cancer cell apoptosis. The present study examined how the combination of α­PA and 5­FU affects the suppression of human colon cancer cells by promoting apoptosis. The impact of this treatment on cell viability, apoptosis, and the expression levels of Bcl­2 family members, caspase family members and mitochondria­related molecules in HT­29 cells was assessed by the MTT assay, immunocytochemistry, western blotting and quantitative PCR. The combination of 5­FU and α­PA had a synergistic inhibitory effect on cell viability, as determined by assessing the combination index value. Bax protein expression levels were higher in the 50, 100 or 250 µM α­PA combined with 5­FU groups compared with those in the 5­FU alone group (P<0.05). By contrast, Bcl­2 protein expression levels and mitochondrial membrane potential (MMP, ΔΨm) were lower in the 100 or 250 µM α­PA combined with 5­FU groups than those in the 5­FU alone group (P<0.05). In addition, hexokinase­2 (HK­2) protein expression levels were lower in the 50, 100 or 250 µM α­PA combined with 5­FU groups than those in the 5­FU alone group (P<0.05). Compared with 5­FU alone, after HT­29 cells were treated with 50, 100 or 250 µM α­PA combined with 5­FU, the mRNA expression levels of extrinsic­induced apoptotic molecules, including caspase­8 and Bid, were higher (P<0.05). Treatment with 50, 100 or 250 µM α­PA combined with 5­FU also increased the mRNA expression levels of cytochrome c, caspase­9 and caspase­3, regulating intrinsic apoptosis (P<0.05). These results showed that α­PA and 5­FU had a synergistic effect on reducing the viability of human colon cancer HT­29 cells by inducing extrinsic and intrinsic apoptosis pathways. The mechanism by which apoptosis is induced may involve the intrinsic apoptosis pathway that activates the mitochondria­dependent pathway, including regulating the expression levels of Bcl­2 family members, including Bax, Bcl­2 and Bid, regulating MMP and HK­2 expression levels, and increasing the expression of caspase cascade molecules, including caspase­9 and caspase­3. In addition, it may involve the extrinsic apoptosis pathway that activates caspase­8 and caspase­3 leading to apoptosis.

Synthetic polyploidization induces enhanced phytochemical profile and biological activities in Thymus vulgaris L. essential oil.

Essential oil from Thymus vulgaris L. has valuable therapeutic potential that is highly desired in pharmaceutical, food, and cosmetic industries. Considering these advantages and the rising market demand, induced polyploids were obtained using oryzalin to enhance essential oil yield. However, their therapeutic values were unexplored. So, this study aims to assess the phytochemical content, and antimicrobial, antioxidant, and anti-inflammatory activities of tetraploid and diploid thyme essential oils. Induced tetraploids had 41.11% higher essential oil yield with enhanced thymol and γ-terpinene content than diploid. Tetraploids exhibited higher antibacterial activity against all tested microorganisms. Similarly, in DPPH radical scavenging assay tetraploid essential oil was more potent with half-maximal inhibitory doses (IC50) of 180.03 µg/mL (40.05 µg TE/mg) than diploid with IC50 > 512 µg/mL (12.68 µg TE/mg). Tetraploids exhibited more effective inhibition of in vitro catalytic activity of pro-inflammatory enzyme cyclooxygenase-2 (COX-2) than diploids at 50 µg/mL concentration. Furthermore, molecular docking revealed higher binding affinity of thymol and γ-terpinene towards tested protein receptors, which explained enhanced bioactivity of tetraploid essential oil. In conclusion, these results suggest that synthetic polyploidization using oryzalin could effectively enhance the quality and quantity of secondary metabolites and can develop more efficient essential oil-based commercial products using this induced genotype.

The behavioral sensitivity of mice to acyclic, monocyclic, and bicyclic monoterpenes.

Monoterpenes are a large class of naturally occurring fragrant molecules. These chemicals are commonly used in olfactory studies to survey neural activity and probe the behavioral limits of odor discrimination. Monoterpenes (typically in the form of essential oils) have been used for centuries for therapeutic purposes and have pivotal roles in various biological and medical applications. Despite their importance for multiple lines of research using rodent models and the role of the olfactory system in detecting these volatile chemicals, the murine sensitivity to monoterpenes remains mostly unexplored. We assayed the ability of C57BL/6J mice to detect nine different monoterpenes (the acyclic monoterpenes: geraniol, citral, and linalool; the monocyclic monoterpenes: r-limonene, s-limonene, and γ-terpinene; and the bicyclic monoterpenes: eucalyptol, α-pinene, and ß-pinene) using a head-fixed Go / No-Go operant conditioning assay. We found that mice can reliably detect monoterpene concentrations in the low parts per billion (ppb) range. Specifically, mice were most sensitive to geraniol (threshold: 0.7 ppb) and least sensitive to γ-terpinene (threshold: 18.1 ppb). These estimations of sensitivity serve to set the lower limit of relevant monoterpene concentrations for functional experiments in mice. To define an upper limit, we estimated the maximum concentrations that a mouse may experience in nature by collating published headspace analyses of monoterpene concentrations emitted from natural sources. We found that natural monoterpenes concentrations typically ranged from ~1 to 1000 ppb. It is our hope that this dataset will help researchers use appropriate monoterpene concentrations for functional studies and provide context for the vapor-phase delivery of these chemicals in studies investigating their biological activity in mice.

[Accumulation and biosynthesis mechanism of volatile oils in glandular scale of Agastache rugosa].

The volatile oils are the effective components of Agastache rugosa, which are stored in the glandular scale. The leaves of pulegone-type A. rugosa were used as materials to observe the leaf morphology of A. rugosa at different growth stages, and the components of volatile oils in gland scales were detected by GC-MS. At the same time, qRT-PCR was used to determine the relative expression of key enzyme genes in the biosynthesis pathway of monoterpenes in volatile oils. The results showed that the density of A. rugosa glandular scale decreased first and then tended to be stable. With the growth of leaves, the relative content of pulegone decreased from 79.26% to 3.94%(89.97%-41.44%), while that of isomenthone increased from 2.43% to 77.87%(0.74%-51.01%), and the changes of other components were relatively insignificant. The correlation analysis between the relative content of monoterpenes and the relative expression levels of their key enzyme genes showed that there was a significant correlation between the relative content of menthone and isomenthone and the relative expression levels of pulegone reductase(PR)(r>0.6, P<0.01). To sum up, this study revealed the accumulation rules of the main components of the contents of the glandular scale of A. rugosa and the expression rules of the key enzyme genes for biosynthesis, which provided a scientific basis and data support for determining the appropriate harvesting period and quality control of the medicinal herbs. This study also initially revealed the biosynthesis mechanism of the monoterpenes mainly composed of pulegone and isomenthone in A. rugosa, laying a foundation for further research on the molecular mechanism of synthesis and accumulation of monoterpenes in A. rugosa.

Ability of Selected Monoterpenes to Reduce Fe(III) Ions Being Pro-Neurodegenerative Factors: Tests Based on a FRAP Reaction Extended to 48 Hours.

Monoterpenes are secondary plant metabolites, and such volatile compounds have antioxidant, antibacterial, antiviral, and enzyme inhibitory properties. These compounds are also able to reduce the potentially pro-neurodegenerative trace metal ions that can be sources of free radicals. One basic method used to evaluate the ability of chemical compounds to reduce Fe(III) is FRAP. To date, most studies based on a FRAP assay were performed within several dozen minutes. However, taking into account the diversity of compounds, it is justified to observe their activity over a much longer period of time. The present study aimed to observe the activity of isopulegol, γ-terpinene, α-terpinene, linalool, carvone, citral, and α-phellandrene over a 48 h period. Our study indicates that the lengthened reaction period enhanced activity from several dozen to several hundred percent. The obtained results also revealed an explicit high correlation of the increase in the activity of compounds with the increase in monoterpene concentration. Due to the hydrophobic character of monoterpenes, the FRAP method was modified by the addition of Tween 20. The highest activity was obtained for α-terpinene and γ-terpinene.

Flavor characterization of Citri Reticulatae Pericarpium (Citrus reticulata 'Chachiensis') with different aging years via sensory and metabolomic approaches.

Guangchenpi (GCP), which is the peel of Citrus reticulata 'Chachiensis', is widely used as an herbal medicine, tea and food ingredient in southeast Asia. Prolonging its aging process results in a more pleasant flavor and increases its profitability. Through the integration of sensory evaluation with flavoromic analysis approaches, we evaluated the correlation between the flavor attributes and the profiles of the volatiles and flavonoids of GCP with various aging years. Notably, d-limonene, γ-terpinene, dimethyl anthranilate and α-phellandrene were the characteristic aroma compounds of GCP. Besides, α-phellandrene and nonanal were decisive for consumers' perception of GCP aging time due to changes of their odor activity values (OAVs). The flavor attributes of GCP tea liquid enhanced with the extension of aging time, and limonene-1,2-diol was identified as an important flavor enhancer. Combined with machine learning models, key flavor-related metabolites could be developed as efficient biomarkers for aging years to prevent GCP adulteration.

Assessment of Trachyspermum ammi essential oil against Aspergillus flavus, aflatoxin B1 contamination, and post-harvest quality of Sorghum bicolor.

The present investigation explored the antifungal effectiveness of Trachyspermum ammi essential oil (TAEO) against Aspergillus flavus, aflatoxin B1 (AFB1) contamination, and its mechanism of action using biochemical and computational approaches. The GC-MS result revealed the chemical diversity of TAEO with the highest percentage of γ-terpinene (39 %). The TAEO exhibited minimum inhibitory concentration against A. flavus growth (0.5 µL/mL) and AFB1 (0.4 µL/mL) with radical scavenging activity (IC50 = 2.13 µL/mL). The mechanism of action of TAEO was associated with the alteration in plasma membrane functioning, antioxidative defense, and carbon source catabolism. The molecular dynamic result shows the multi-regime binding of γ-terpinene with the target proteins (Nor1, Omt1, and Vbs) of AFB1 biosynthesis. Furthermore, TAEO exhibited remarkable in-situ protection of Sorghum bicolor seed samples against A. flavus and AFB1 contamination and protected the nutritional deterioration. Hence, the study recommends TAEO as a natural antifungal agent for food protection against A. flavus mediated biodeterioration.