Glandular Trichomes and Essential Oils Variability in Species of the Genus Phlomis L.: A Review.

The genus Phlomis is one of the largest genera in the Lamiaceae family and includes species used since ancient times in traditional medicine, as flavoring for food and as fragrance in cosmetics. The secretory structures (represented by glandular trichomes) as well as the essential oils produced by them constitute the subject of this review. While representatives of this genus are not typically regarded as large producers of essential oils compared to other species of the Lamiaceae family, the components identified in their essential oils and their biological properties necessitate more investigation of this genus. A comprehensive analysis of the specialized literature was conducted for each of the 93 currently accepted species to identify all the results obtained by researchers regarding the secretory structures and essential oils of this genus up to the present time. Glandular trichomes, still insufficiently studied, present morphological peculiarities that differentiate this genus within the family: they are of two categories: capitate (with a wide distribution in this genus) and dendroid. The peltate trichomes, characteristic of many species of this family, are absent. The essential oils from the species of the genus Phlomis have been much more widely studied than the secretory structures. They show considerable variability depending on the species and the environmental conditions.

Genome Mining of Fungal Unique Trichodiene Synthase-like Sesquiterpene Synthases.

Sesquiterpenoids served as an important source for natural product drug discovery. Although genome mining approaches have revealed numerous novel sesquiterpenoids and biosynthetic enzymes, the comprehensive landscape of fungal sesquiterpene synthases (STSs) remains elusive. In this study, 123 previously reported fungal STSs were subjected to phylogenetic analysis, resulting in the identification of a fungi-specific STS family known as trichodiene synthase-like sesquiterpene synthases (TDTSs). Subsequently, the application of hidden Markov models allowed the discovery of 517 TDTSs from our in-house fungi genome library of over 400 sequenced genomes, and these TDTSs were defined into 79 families based on a sequence similarity network. Based on the novelty of protein sequences and the completeness of their biosynthetic gene clusters, 23 TDTS genes were selected for heterologous expression in Aspergillus oryzae. In total, 10 TDTSs were active and collectively produced 12 mono- and sesquiterpenes, resulting in the identification of the first chamipinene synthase, as well as the first fungi-derived cedrene, sabinene, and camphene synthases. Additionally, with the guidance of functionally characterized TDTSs, we found that TDTSs in Family 1 could produce bridged-cyclic sesquiterpenes, while those in Family 2 could synthesize spiro- and bridged-cyclic sesquiterpenes. Our research presents a new avenue for the genome mining of fungal sesquiterpenoids.

Biogenic volatile organic compounds in forest therapy base: A source of air pollutants or a healthcare function?

Air pollution poses a significant threat to public health, while biogenic volatile organic compounds (BVOCs) play a crucial role in both aspects. However, the unclear relationship between BVOCs and air pollutants in the under-canopy space limits the accuracy of air pollution control and the exploitation of forest healthcare functions. To clarify the variation of BVOCs in forest therapy bases, and their impacts on ozone (O3) and fine particulate matter (PM2.5) at nose height, total VOCs (TVOCs) in the forest were collected during typical sunny days, while air pollutants and meteorological factors were observed simultaneously. The results showed that the branch-level emissions of P. tabuliformis were dominated by healthcare-effective monoterpenoids, with only α-pinene having relative air concentrations of over 5 % in forest air samples. The correlation between concentrations of under-canopy TVOCs and emission rates of BVOCs from P. tabuliformis was weak (p > 0.09) in all seasons. However, the correlation between concentrations of TVOCs and the concentrations of O3 and PM2.5 showed clear seasonal differences. In spring, TVOCs only showed a significant negative correlation with PM2.5 in the forest (p < 0.01). In summer and autumn, TVOCs were significantly negatively correlated with both O3 (p < 0.001) and PM2.5 (p < 0.01). Specifically, the negative linear relationships were more pronounced for O3 and oxygenated VOCs in autumn (R2 = 0.40, p < 0.001) than for other relationships. The relationship between air pollutant concentrations inside and outside the forest also showed significant seasonal differences, generally characterized by a weaker correlation between them during seasons of strong emissions. Therefore, BVOCs in coniferous forests are health functions as they can provide healthcare effects and mitigate the concentration of air pollutants in the forest, and the establishment of forest therapy bases in rural areas with low NOx can be a sensible approach to promote good health, well-being, and sustainable development.

Non-clinical investigations about cytotoxic and anti-platelet activities of gamma-terpinene.

Gamma-terpinene (γ-TPN) is a cyclohexane monoterpene isolated from plant essential oils, such as tea tree (Melaleuca alternifolia), oregano (Origanum vulgare), rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris Marchand), and eucalyptus (Eucalyptus sp.). Terpenes are widely studied molecules pharmacologically active on the cardiovascular system, hemostasis, and antioxidant actions. Herein, it was investigated the cytotoxic and antiplatelet activity of γ-TPN using different non-clinical laboratory models. For in silico evaluation, the PreADMET, SwissADME, and SwissTargetPrediction softwares were used. Molecular docking was performed using the AutoDockVina and BIOVIA Discovery Studio databases. The cytotoxicity of γ-TPN was analyzed by the MTT assay upon normal murine endothelial SVEC4-10 and fibroblast L-929 cells. Platelet aggregation was evaluated with platelet-rich (PRP) and platelet-poor (PPP) plasma from spontaneously hypertensive rats (SHR), in addition to SVEC4-10 cells pre-incubated with γ-TPN (50, 100, and 200 µM) for 24 h. SHR animals were pre-treated by gavage with γ-TPN for 7 days and divided into four groups (negative control, 25, 50, and 100 mg/kg). Blood samples were collected to measure nitrite using the Griess reagent. Gamma-TPN proved to be quite lipid-soluble (Log P = +4.50), with a qualified profile of similarity to the drug, good bioavailability, and adequate pharmacokinetics. It exhibited affinity mainly for the P2Y12 receptor (6.450 ± 0.232 Kcal/mol), moderate cytotoxicity for L-929 (CC50 = 333.3 µM) and SVEC 4-10 (CC50 = 366.7 µM) cells. The presence of γ-TPN in SVEC 4-10 cells was also able to reduce platelet aggregation by 51.57 and 44.20% at lower concentrations (50 and 100 µM, respectively). Then, γ-TPN has good affinity with purinergic receptors and an effect on the reversal of platelet aggregation and oxidative stress, being promising and safe for therapeutic targets and subsequent studies on the control of thromboembolic diseases.

Increase of the indoor concentration of volatile organic compounds after the use of incense and scented candle in studio apartments determined using passive sampling.

Burning incenses and scented candles may provide harmful chemicals. Although many studies have evaluated volatile organic chemicals emitted by their use and related health risks, extension of our understanding for guiding appropriate use under various use conditions is necessary. In this study, emission characteristics of commercial incenses and scented candles were evaluated in a laboratory chamber using real-time measurement and the time-weighted average exposure concentrations of monoaromatic compounds and monoterpenes were assessed using passive samplers while volunteers living in a studio apartment use them. After burning incense, the average levels of benzene increased from 1.4 to 100 µg m-3. The presence of a wood core in commercial incense products was the main cause of high benzene emission by burning them although the increase in benzene was also influenced by factors such as the brand of the products, the number of incense sticks burned, the duration of each burning session, and ventilation period. Electrical warming of scented candles increased the levels of monoterpenes by factors of 16-30 on average. Considering the emission characteristics found in this study, exposure to benzene and monoterpenes could be mitigated by cautious use of those products in residential areas.

Ten cyclopentanoid monoterpenes from the whole plant of Rehmannia piasezkii maxim.

Ten new cyclopentanoid monoterpenes (1-10) were isolated from the whole plant of Rehmannia piasezkii. The structures of these compounds were elucidated based on spectroscopic data analysis. In in-vitro assays, compounds 3, 7, and 9 exhibited weak hepatoprotective activities against APAP-induced HepG2 cell damage. Compound 9 exhibited protective effect on hapassocin carbon tetrachloride model.

Quality criteria, chemical composition and antimicrobial activity of the essential oil of Mentha suaveolens Ehrh.

The aim of the present study is the valorization of the essential oil of Mentha suaveolens Ehrh. The research plan and methods included 3-axis: the first axis consists of studying the organoleptic and physicochemical characterization of the essential oil, the second is the chemical analysis carried out by Gas Chromatography/Mass Spectrometry (GC/MS) and the third consists of evaluating its antimicrobial activity against selected microorganisms. The results obtained for the organoleptic and physicochemical properties are as follows: appearance: Liquid, mobile and clear, odor: Strong odor characteristic of Mentha suaveolens Ehrh, color: Pale yellow; relative density (0.92), miscibility with ethanol (1V/2V), freezing point (Tfreezing < -10 °C), refractive index (1.5256), rotating power (+0.825), acid index (1.68), ester index (68.44), saponification index (70.13) and iodine index (12.05).Chemical analysis identified 69 compounds which are mostly oxygenated monoterpenes such as piperitenone oxide (32.55%), pulegone (10.14%), piperitone oxide (8.34%), etc. The microbiological tests were carried out by an agar diffusion test using the essential oil of Mentha suaveolens Ehrh. The microbiological tests were carried out by a diffusion test on agar, these tests are carried out on six microbial strains (five bacteria and one yeast).The inhibitory effect of our oil is well marked against bacteria: Proteus mirabilis (17.50 ± 0.70 mm at 50 µL/mL), Enterococcus faecalis (17.00 ± 1.00 mm at 50 µL/mL) and Staphylococcus coagulase negative (16.33 ± 0.57 mm at 50 µL/mL) while it was moderate against Escherichia coli (14.33 ± 1.15 mm at 50 µL/mL) and Streptococcus spp (13.00 ± 0.00 mm at 50 µL/mL) as well as against yeast, Candida albicans (15.33 ± 1.52 mm at 50 µL/mL). It appears from these results that our oil is of high quality and can be used in several areas. The results obtained are therefore promising and thus open the way for manufacturers to use this essential oil of Mentha suaveolens Ehrh in the pharmaceutical, cosmetic, agricultural and food industries.

DFT Studies of the Activity and Reactivity of Limonene in Comparison with Selected Monoterpenes.

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.

Combined sensory, volatilome and transcriptome analyses identify a limonene terpene synthase as a major contributor to the characteristic aroma of a Coffea arabica L. specialty coffee.

BACKGROUND: The fruity aromatic bouquet of coffee has attracted recent interest to differentiate high value market produce as specialty coffee. Although the volatile compounds present in green and roasted coffee beans have been extensively described, no study has yet linked varietal molecular differences to the greater abundance of specific substances and support the aroma specificity of specialty coffees. RESULTS: This study compared four Arabica genotypes including one, Geisha Especial, suggested to generate specialty coffee. Formal sensory evaluations of coffee beverages stressed the importance of coffee genotype in aroma perception and that Geisha Especial-made coffee stood out by having fine fruity, and floral, aromas and a more balanced acidity. Comparative SPME-GC-MS analyses of green and roasted bean volatile compounds indicated that those of Geisha Especial differed by having greater amounts of limonene and 3-methylbutanoic acid in agreement with the coffee cup aroma perception. A search for gene ontology differences of ripening beans transcriptomes of the four varieties revealed that they differed by metabolic processes linked to terpene biosynthesis due to the greater gene expression of prenyl-pyrophosphate biosynthetic genes and terpene synthases. Only one terpene synthase (CaTPS10-like) had an expression pattern that paralleled limonene loss during the final stage of berry ripening and limonene content in the studied four varieties beans. Its functional expression in tobacco leaves confirmed its functioning as a limonene synthase. CONCLUSIONS: Taken together, these data indicate that coffee variety genotypic specificities may influence ripe berry chemotype and final coffee aroma unicity. For the specialty coffee variety Geisha Especial, greater expression of terpene biosynthetic genes including CaTPS10-like, a limonene synthase, resulted in the greater abundance of limonene in green beans, roasted beans and a unique citrus note of the coffee drink.

Effectiveness and chemical insights: Exploring interactions between nanomicelles and monoterpenoids for head lice treatment.

This study evaluates the pediculicidal activity of nanoformulations containing different binary essential oil component mixtures (eugenol:linalool, 1,8 -cineole:linalool, and eugenol:thymol) using immersion bioassays. These have allowed us to evaluate the knockdown time affecting 50% of the individuals (KT50). In addition, the type of interaction between the components in each mixture was established in terms of the combination index (IC). The KT50 values were 6.07; 8.83; 7.17 and 27.23 h for linalool, 1,8 -cineole, eugenol, and thymol, respectively. For the eugenol:linalool mixtures, the efficacy was lower or equal to that obtained for the nanoformulations of the pure compounds, with values of KT50 about 13.33, 8.16 and 6.71 h for mixtures with ratios 3:1, 1:1 and 1:3, respectively. These mixtures present IC > 1, evidencing antagonistic interaction, which is enhanced with eugenol content. In the case of the binary mixtures of 1,8 -cineole: linalool, KT50 values were similar to those obtained for eugenol:linalool mixtures with similar ratios. In this case, IC assumes values close to unity, suggesting additive interactions independently of the mixture composition. On the other side, mixtures of eugenol:thymol with 1:1 and 1:3 ratios showed values of 9.40 and 32.93 h, while the mixture with a 3:1 ratio showed the greatest effectiveness (KT50 of 4.42 h). Eugenol:thymol mixtures show synergistic interaction (IC < 1) for combinations 3:1 and 1:1, while no interaction was observed for 1:3 combination. This indicates that eugenol enhances thymol activity. These results must be considered an important step forward to the development of effective pediculicidal nanoformulations based on botanical compounds.

Antinociceptive Analysis of Natural Monoterpenes Eugenol, Menthol, Carvacrol and Thymol in a Zebrafish Larval Model.

In the last decade, a considerable number of studies have broadened our knowledge of the nociceptive mechanisms of pain, a global health problem in both humans and animals. The use of herbal compounds such as eugenol, menthol, thymol, and carvacrol as analgesic agents has accompanied the growing interest in this area, offering a possible solution for this complex problem. Here, we aimed to explore how these natural substances-at three different concentrations (2, 5 and 10 mg/L)-affect the pain responses in zebrafish (Danio rerio) larvae exposed to 0.05% acetic acid (AA) for 1 min. By analysing the activity of acetylcholinesterase (AChE), 5'-ectonucleotidase and NTPDases, as well as aversion and exploratory behaviours, it was observed that that although all substances were effective in counteracting the pain stimulus, the concentration range within which they do so might be very limited. Eugenol, despite its acknowledged properties in fish anaesthesia, failed to alleviate the pain stimulus at low concentrations. Contrastingly, menthol exhibited the most promising results at the lowest concentrations tested. Overall, it is concluded that menthol might be a good analgesic for this species, qualifying it as a substance of interest for prospective studies.

Investigating the industrial origin of terpenoids in a coastal city in northern France: A source apportionment combining anthropogenic, biogenic, and oxygenated VOC.

Terpenoids have long been known to originate from natural sources. However, there is growing evidence for emissions from anthropogenic activities in cities, in particular from the production, manufacturing, and use of household solvents. Here, as part of the DATAbASE (Do Anthropogenic Terpenoids mAtter in AtmoSpheric chEmistry?) project, we investigate for the first time the potential role of industrial activities on the terpenoid burden in the urban atmosphere. This study is based on continuous VOC observations from an intensive field campaign conducted in July 2014 at an industrial-urban background site located in Dunkirk, Northern France. More than 80 VOCs including oxygenated and terpenoid compounds were measured by on-line Thermal Desorption Gas Chromatography with a Flame Ionization Detection (TD-GC-FID) and Proton Transfer Reaction-Time of Flight Mass Spectrometry (PTR-ToFMS). Isoprene, α-pinene, limonene and the sum of monoterpenes were the terpenoids detected at average mixing ratios of 0.02 ± 0.02 ppbv, 0.02 ± 0.02 ppbv, 0.01 ± 0.01 ppbv and 0.03 ± 0.05 ppbv, respectively. Like other anthropogenic VOCs, the mixing ratios of terpenoids significantly increase downwind the industrial plumes by one order of magnitude. Positive Matrix Factorization (PMF) was performed to identify the different emission sources of VOCs and their contribution. Six factors out of the eight factors extracted (r2 = 0.95) are related to industrial emissions such as solvent use, chemical and agrochemical storage, metallurgy, petrochemical, and coal-fired industrial activities. From the correlations between the industrial-type PMF factors, sulfur dioxide, and terpenoids, we determined their emissions ratios and we quantified for the first time their industrial emissions. The highest emission ratio is related to the alkene-dominated factor and is related to petrochemical, metallurgical and coal-fired industrial activities. The industrial emissions of monoterpenes equal 8.1 ± 4.3 tons/year. Those emissions are as significant as the non-industrialized anthropogenic ones estimated for the Paris megacity.

Investigating efficacy of colchicine plus phenolic monoterpenes fraction as a potential treatment for patients diagnosed with COVID-19: A randomized controlled parallel clinical trial.

Background: COVID-19 now is a serious concern for the world healthcare system. This study aimed to investigate possible therapeutic effect of colchicine and phenolic monoterpenes accompanied by standard care of treatment (SCT) in patients diagnosed with COVID-19. Methods: In this randomized controlled parallel clinical trial, a total number of 179 (of 200) patients with confirmed COVID-19 were enrolled according to the inclusion and exclusion criteria. The patients were allocated by simple randomization method into two groups control (receiving SCT with 71 patients) and intervention (receiving SCT plus colchicine and phenolic monoterpenes with 107 patients). The mortality ratio during hospitalization as well as a 2-week follow-up, ICU admission rate, and hospitalization duration were assessed as main outcomes. Results: The mortality ratio was 0.9% (1/108) and 8.45% (6/71) in the intervention and the control groups (p-value = 0.035) respectively, these ratios after a 14-day follow-up were 1.85% (2/108), and 9.85 (7/71) respectively (p-value = 0.031). Also, the ICU admission was significantly lower (p-value = 0.006) in the intervention group 2/108 (1.85%) compared with controls 10/71 (14.08%). Moreover, the duration of hospitalization followed a similar pattern to ICU admission with 4.17 ± 1.34 vs. 6.39 ± 2.59 days in the intervention and control groups respectively (p-value< 0.001). Furthermore, no significant side effect was found between the groups. Conclusion: According to the results, the combination of colchicine plus phenolic monoterpenes could be an additive treatment for the SCT. The authors strongly recommend further trials on this combination with other SCTs.

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.

Transcriptome and volatile compounds analyses of floral development provide insight into floral scent formation in Paeonia lactiflora 'Wu Hua Long Yu'.

Herbaceous peony (Paeonia lactiflora) is a well-known ornamental plant in China, celebrated for its beautiful flowers that can emit fragrances. However, exact molecular mechanisms governing synthesis of floral volatiles within herbaceous peony remain unclear. To address this gap in knowledge, our study focused on analyzing the transcriptome and the levels of floral volatile compounds in P. lactiflora 'Wu Hua Long Yu' at different stages of flower development. Using gas chromatography-mass spectrometry (GC-MS), we obtained eighteen major volatile compounds, with monoterpenes being the dominant components among them. Our transcriptome analysis, based on pooled sequencing data, revealed the most differentially expressed genes (DEGs) existed between stages S1 and S3 of flower development. Among these DEGs, we identified 89 functional genes associated with the synthesis of volatile monoterpenes, with 28 of these genes showing a positive correlation with the release of monoterpenes. Specifically, key regulators of monoterpene synthesis in herbaceous peony appear to be 1-deoxy-D-xylulose 5-phosphate synthase (DXS), geranyl pyrophosphate synthase (GPPS), and terpene synthase (TPS). Additionally, our study identified some transcription factors (TFs) that may be involved in the biosynthesis of monoterpenes. These discoveries offer invaluable illumination into the intricate molecular underpinnings orchestrating the generation of floral fragrances in herbaceous peonies, and they offer a foundation for further research to identify and utilize candidate gene resources for this purpose.

Targeted metabolomics analysis based on HS-SPME-GC-MS to discriminate geographical origin of 'Muscat Hamburg' grape and wine.

Monoterpenes are typical aroma components in muscat grapes and wines, closely related to its geographical origins. However, the mechanism underlying the geographical differences of monoterpenes remains to be elucidated, especially in the Chinese viticulture regions. This study investigated the diversity of six Chinese viticultural vineyards (YT, XF, SS, XX, WW and CL) in the monoterpene composition of Vitis vinifera L. cv.'Muscat Hamburg' grapes and the resulted wines. Monoterpenes were analyzed by HS-SPME- GC-MS. The total amount of free and bound monoterpenes varied dramatically between grapes of different vineyards, and their contents were obviously higher in YT region grapes. The OAVs for 18 monoterpenes of grapes from the YT vineyard were relative higher than those of other regions, and the floral odor could distinguish grapes from different regions. The total free monoterpenes were highest in the YT region wine. Concentrations of total bound monoterpenes ranged from 711.13 µg/L (XF region) to 1078.30 µg/L (CL region). A correlation analysis showed that all monoterpenes showeda positive correlation with mean relative humidity, sum rainfall, and a negative correlation with sum duration of sunshine and mean temperature. This study would provide some new insights to understand the geographical differences of monoterpenes, and the results would facilitate the effective viticultural treatment of grapes to improve the quality of the aroma.

Metabolic crosstalk between hydroxylated monoterpenes and salicylic acid in tomato defense response against bacteria.

Hydroxylated monoterpenes (HMTPs) are differentially emitted by tomato (Solanum lycopersicum) plants resisting bacterial infection. We have studied the defensive role of these volatiles in the tomato response to bacteria, whose main entrance are through stomatal apertures. Treatments with some HMTPs resulted in stomatal closure and pathogenesis-related protein 1 (PR1) induction. Particularly, α-terpineol induced stomatal closure in a salicylic acid (SA) and abscisic acid-independent manner and conferred resistance to bacteria. Interestingly, transgenic tomato plants overexpressing or silencing the monoterpene synthase MTS1, which displayed alterations in the emission of HMTPs, exhibited changes in the stomatal aperture but not in plant resistance. Measures of both 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEcPP) and SA levels revealed competition for MEcPP by the methylerythritol phosphate (MEP) pathway and SA biosynthesis activation, thus explaining the absence of resistance in transgenic plants. These results were confirmed by chemical inhibition of the MEP pathway, which alters MEcPP levels. Treatments with BTH, a SA functional analogue, conferred enhanced resistance to transgenic tomato plants overexpressing MTS1. Additionally, these MTS1 overexpressors induced PR1 gene expression and stomatal closure in neighbouring plants. Our results confirm the role of HMTPs in both intra and inter-plant immune signalling and reveal a metabolic crosstalk between the MEP and SA pathways in tomato plants.

Limonene Exerts Anti-Inflammatory Effect on LPS-Induced Jejunal Injury in Mice by Inhibiting NF-κB/AP-1 Pathway.

The human gastrointestinal system is a complex ecosystem crucial for well-being. During sepsis-induced gut injury, the integrity of the intestinal barrier can be compromised. Lipopolysaccharide (LPS), an endotoxin from Gram-negative bacteria, disrupts the intestinal barrier, contributing to inflammation and various dysfunctions. The current study explores the protective effects of limonene, a natural compound with diverse biological properties, against LPS-induced jejunal injury in mice. Oral administration of limonene at dosages of 100 and 200 mg/kg was used in the LPS mouse model. The Murine Sepsis Score (MSS) was utilized to evaluate the severity of sepsis, while serum levels of urea and creatinine served as indicators of renal function. Our results indicated that LPS injection induced renal function deterioration, evidenced by elevated serum urea and creatinine levels compared to control mice. However, pretreatment with limonene at doses of 100 and 200 mg/kg mitigated this decline in renal function, evidenced from the reduced levels of serum urea and creatinine. Limonene demonstrated anti-inflammatory effects by reducing pro-inflammatory cytokines (TNF-α, IL-1ß, COX-2), suppressing the TLR4/NF-κB/AP-1 but not IRF3 signaling pathways, and modulating oxidative stress through Nrf2 activation. The results suggest that limonene holds promise as a potential therapeutic agent for mitigating intestinal inflammation and preserving gastrointestinal health.

Disclosing the Functional Potency of Three Oxygenated Monoterpenes in Combating Microbial Pathogenesis: From Targeting Virulence Factors to Chicken Meat Preservation.

During the last few decades, there has existed an increased interest in and considerable consumer preference towards using natural and safe compounds derived from medicinal plants as alternatives to synthetic preservatives to combat microbial pathogenicity. In this regard, the present study investigated the possible synergistic interactions of the anti-foodborne bacterial capacity of linalool (L), eucalyptol (E), and camphor (C). The antibacterial synergistic effect was determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica Typhimurium, and Escherichia coli. The optimal predicted mixture showed the highest antibacterial activity at 33.5%, 33.2%, and 33.4% of L, E, and C, respectively. Molecular docking simulations displayed that the studied monoterpenes have effective antibacterial inhibitory effects by impeding specific virulence factors such as sortase A, listeriolysin O, L, D-Transpeptidase, and polyphosphate kinase. The selected triple combination of L, E, and C was applied as a natural preservative in minced chicken breast meat. In this regard, 1 MIC (16 µg/mL), 1.5 MIC (24 µg/mL), and 2 MIC (32 µg/mL) of L. monocytogenes were used, and the microbiological, physicochemical, and sensory analyses were monitored for 14 days of storage at 4 °C. The L/E/C mixture at different levels could delay lipid and protein oxidation, inhibit the microorganisms, and maintain the sensory attributes. Additionally, by using chemometric tools, strong connections between physicochemical properties, microbiological parameters, and organoleptic attributes were established. Concisely, this research confers the importance of the use of blended monoterpenes and highlights their antibacterial mode of action, effectiveness, and synergistic effects as a powerful and safe bio-preservative formulation in chicken meat products.

Antimicrobial activity of carvacrol and its derivatives on Mycobacterium spp.: systematic review of preclinical studies.

Background: The scope of the study was to analyze original preclinical studies on the antimicrobial effects of carvacrol and derivatives on the Mycobacterium genus. Materials & methods: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, four databases (PubMed, Web of Science, SCOPUS and EMBASE) were searched. Results: The search retrieved 392 records, of which 11 papers were selected. Heterogeneity in the techniques and mycobacterial targets was observed. Carvacrol demonstrated synergistic antimycobacterial activity with rifampicin against multidrug-resistant Mycobacterium tuberculosis on membranes and biofilms. In silico approaches showed specific targets in mycobacteria, by inhibition and molecular docking assays, on the enzyme chorismate mutase and the heat shock protein 16.3. Conclusion: Carvacrol has been shown to be a scaffold candidate for future molecules with activity against mycobacteria.