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Phytochemistry Oct 2021α-Pinene represents a member of the monoterpene class and is highly distributed in higher plants like conifers, Juniper ssp. and Cannabis ssp. α-Pinene has been used... (Review)
Review
α-Pinene represents a member of the monoterpene class and is highly distributed in higher plants like conifers, Juniper ssp. and Cannabis ssp. α-Pinene has been used to treat respiratory tract infections for centuries. Furthermore, it plays a crucial role in the fragrance and flavor industry. In vitro assays have shown an enantioselective profile of (+)- and (-)-α-pinene for antibacterial and insecticidal activity, respectively. Recent research has used pre-validated biological structures to synthesize new chemical entities with pharmacological and herbicidal activities. In summary, this review focuses on recent literature covering synthetic pathways of flavor compounds and scaffold hopping based on the α-pinene core domaine, as well as the (enantioselective) activities of α-pinene. Recent approaches for authenticity control of essential oils based on their enantiomeric profile are also presented.
Topics: Bicyclic Monoterpenes; Juniperus; Monoterpenes; Oils, Volatile
PubMed: 34365295
DOI: 10.1016/j.phytochem.2021.112857 -
Proteomics Jul 2022Complex mixtures of bioactive ingredients in plant essential oils present complex chemistries which involve different modes of action. An increasing body of scientific...
Complex mixtures of bioactive ingredients in plant essential oils present complex chemistries which involve different modes of action. An increasing body of scientific reports has recently focused on the acaricidal activities of plant essential oils attributed to their monoterpene components, but information about their underlying molecular mechanism of action is scarce. Here, after the chemical analysis of lemongrass oil, a proteomic analysis of the ovary, salivary gland, and midgut of Haemaphysalis longicornis exposed to Cymbopogon citratus (lemongrass) essential oil was performed via data-independent acquisition mass spectrometry (DIA-MS) technology to further elucidate the molecular mechanisms involved. Pathway analysis reveals the activation of metabolic pathways mediated by oxidoreductases and transferases. Furthermore, the upregulation of various calcium-associated proteins and the upregulation of cytochrome c1, cytochrome c oxidase polypeptide IV, and programmed cell death protein 6-like isoform X1 suggest a cytotoxic mode of action via the formation of reactive oxygen species (ROS), mitochondrial Ca overload, mitochondrial uncoupling, and depolarization, and ATP depletion leading to either apoptotic or necrotic death. Morphological alterations observed after the RNAi of a major detoxification enzyme (glutathione S-transferase) merit further investigation. Hence, the cytotoxic mode of action exhibited by C. citratus oil could be vital for the development of eco-friendly acaricide.
Topics: Cymbopogon; Homeostasis; Monoterpenes; Oils, Volatile; Proteomics
PubMed: 34997954
DOI: 10.1002/pmic.202100156 -
Journal of Comparative Physiology. B,... May 2015Many plants produce plant secondary metabolites (PSM) that inhibit digestive enzymes of herbivores, thus limiting nutrient availability. In response, some specialist...
Many plants produce plant secondary metabolites (PSM) that inhibit digestive enzymes of herbivores, thus limiting nutrient availability. In response, some specialist herbivores have evolved digestive enzymes that are resistant to inhibition. Monoterpenes, a class of PSMs, have not been investigated with respect to the interference of specific digestive enzymes, nor have such interactions been studied in avian herbivores. We investigated this interaction in the Greater Sage-Grouse (Phasianidae: Centrocercus urophasianus), which specializes on monoterpene-rich sagebrush species (Artemisia spp.). We first measured the monoterpene concentrations in gut contents of free-ranging sage-grouse. Next, we compared the ability of seven individual monoterpenes present in sagebrush to inhibit a protein-digesting enzyme, aminopeptidase-N. We also measured the inhibitory effects of PSM extracts from two sagebrush species. Inhibition of aminopeptidase-N in sage-grouse was compared to inhibition in chickens (Gallus gallus). We predicted that sage-grouse enzymes would retain higher activity when incubated with isolated monoterpenes or sagebrush extracts than chicken enzymes. We detected unchanged monoterpenes in the gut contents of free-ranging sage-grouse. We found that three isolated oxygenated monoterpenes (borneol, camphor, and 1,8-cineole) inhibited digestive enzymes of both bird species. Camphor and 1,8-cineole inhibited enzymes from chickens more than from sage-grouse. Extracts from both species of sagebrush had similar inhibition of chicken enzymes, but did not inhibit sage-grouse enzymes. These results suggest that specific monoterpenes may limit the protein digestibility of plant material by avian herbivores. Further, this work presents additional evidence that adaptations of digestive enzymes to plant defensive compounds may be a trait of specialist herbivores.
Topics: Adaptation, Biological; Aminopeptidases; Analysis of Variance; Animals; Area Under Curve; Artemisia; Camphanes; Camphor; Cyclohexanols; Digestive System; Enzyme Inhibitors; Eucalyptol; Female; Galliformes; Herbivory; Idaho; Male; Monoterpenes; Species Specificity
PubMed: 25652583
DOI: 10.1007/s00360-015-0890-z -
Food Chemistry Apr 2016Various strategies have been adopted to combat complications caused by Type 2 diabetes mellitus and controlled diet is one of them. Monoterpenes, major constituents of...
Various strategies have been adopted to combat complications caused by Type 2 diabetes mellitus and controlled diet is one of them. Monoterpenes, major constituents of essential oils, are synthesized and widely used as artificial food flavors. A series of twelve monoterpenes were assessed in the present study. Monoterpenes, exhibited low 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity even at high concentrations. Some monoterpenes inhibited α-amylase and α-glucosidase activity and stimulated glucose uptake and lipolysis. Monoterpenes such as (R)-(+)-limonene stimulated both glucose uptake (17.4%) and lipolysis (17.7%); the mRNA expression of glucose transporter 1 (GLUT1) was upregulated but glucose transporter 4 (GLUT4) was unaffected, and adipose triglyceride lipase (ATGL) was suppressed. Taken together, the selected monoterpenes may not confer strong protection against free radicals but nevertheless, their positive influence on lipid and glucose metabolism may have potential in the control of obesity and Type 2 diabetes mellitus.
Topics: 3T3-L1 Cells; Adipocytes; Animals; Biological Transport; Diabetes Mellitus, Type 2; Glucose; Lipid Metabolism; Mice; Monoterpenes
PubMed: 26593489
DOI: 10.1016/j.foodchem.2015.09.042 -
Environmental Science and Pollution... Jun 2021Regional estimates of VOC fluxes focus largely on emissions from the canopy and omit potential contributions from the forest floor including soil, litter and understorey...
Regional estimates of VOC fluxes focus largely on emissions from the canopy and omit potential contributions from the forest floor including soil, litter and understorey vegetation. Here, we measured monoterpene emissions every 2 months over 2 years from logged tropical forest and oil palm plantation floor in Malaysian Borneo using static flux chambers. The main emitted monoterpenes were α-pinene, β-pinene and d-limonene. The amount of litter present was the strongest indicator for higher monoterpene fluxes. Mean α-pinene fluxes were around 2.5-3.5 μg C m h from the forest floor with occasional fluxes exceeding 100 μg C m h. Fluxes from the oil palm plantation, where hardly any litter was present, were lower (on average 0.5-2.9 μg C m h) and only higher when litter was present. All other measured monoterpenes were emitted at lower rates. No seasonal trends could be identified for all monoterpenes and mean fluxes from both forest and plantation floor were ~ 100 times smaller than canopy emission rates reported in the literature. Occasional spikes of higher emissions from the forest floor, however, warrant further investigation in terms of underlying processes and their contribution to regional scale atmospheric fluxes.
Topics: Borneo; Forests; Malaysia; Monoterpenes; Soil
PubMed: 33611733
DOI: 10.1007/s11356-021-13052-z -
Natural Product Research May 2019The aim of this work is to explore the possibility of using the phenolic monoterpenes (PMs) as leading compounds with antifungal activity against plant disease. The...
The aim of this work is to explore the possibility of using the phenolic monoterpenes (PMs) as leading compounds with antifungal activity against plant disease. The antifungal activities of carvacrol and thymol against seven kinds of plant pathogenic fungi were evaluated on mycelium growth rate method, and the results showed that carvacrol and thymol exhibited broad spectrum antifungal activity. Structure requirement for the antifungal activity of PMs was also investigated. The preliminary conclusion was that phenolic hydroxyl and monoterpene were basic structures for the antifungal activity of PMs, and the position of phenolic hydroxyl showed less effect. Ester derivatives of carvacrol and thymol were more effective than carvacrol and thymol against plant pathogenic fungi. We suggested that carvacrol, thymol and their ester derivatives could potentially be used as new fungicide leading compounds.
Topics: Antifungal Agents; Cymenes; Fungi; Microbial Sensitivity Tests; Molecular Structure; Monoterpenes; Oils, Volatile; Plants; Thymol
PubMed: 29334264
DOI: 10.1080/14786419.2017.1419232 -
Journal of Chemical Ecology Sep 2019The koala is a specialist feeder with a diet consisting almost exclusively of potentially toxic eucalypt leaves. Monoterpenes, an abundant class of plant secondary...
The koala is a specialist feeder with a diet consisting almost exclusively of potentially toxic eucalypt leaves. Monoterpenes, an abundant class of plant secondary metabolites in eucalypts, are highly lipophilic. Chronic absorption and systemic exposure can be anticipated for the koala, causing health effects in various ways when consumed in high amounts, but particularly causing alterations in immune function in this species. Therefore, careful leaf selection, efficient detoxification pathways, and other specialist adaptations are required to protect animals from acute intoxication. This is the first paper providing insight into the systemic exposure of koalas to these compounds. Profiles of six selected major monoterpenes were investigated in the ingesta of deceased koalas from four different regions of NSW and South-East Queensland. Concentrations of the same compounds were measured in lymphoid tissues of deceased koalas and in the blood of live koalas from other regions of NSW. Analytical methods included liquid extraction and solid-phase micro-extraction, followed by gas-chromatography/ mass-spectrometry. Concentrations in the ingesta of individual animals vary remarkably, though the average proportions of individual monoterpenes in the ingesta of animals from the four different regions are highly comparable. Blood concentrations of the selected monoterpenes also varied considerably. The highest blood concentrations were found for 1,8-cineole, up to 971 ng/ml. There was similarity between circulating monoterpene profiles and ingesta profiles. Based on the observed lack of similarity between blood and lymph tissue concentrations, individual monoterpenes either exhibit different affinities for lymphatic tissue compared to blood or their accumulation in blood and lymph tissue differs temporally. In general, blood monoterpene concentrations found in koalas were low compared to those reported in other marsupial eucalypt feeders, but significant concentrations of monoterpenes were detected in all samples analysed. This data on blood and lymphatic tissue monoterpene concentrations builds the fundamental groundwork for future research into the effects of dietary monoterpenes on various biological processes of specialist herbivores and into the significance of these animals' metabolic and behavioural strategies for coping with these compounds. We have shown that the systemic exposure of koalas to potentially anti-inflammatory eucalypt monoterpenes is continuous, and we provide data on physiological concentrations which will allow realistic future studies of the effects of monoterpenes on immune cell function.
Topics: Animals; Australia; Eucalyptus; Feeding Behavior; Monoterpenes; Phascolarctidae; Plant Leaves
PubMed: 31422515
DOI: 10.1007/s10886-019-01097-x -
Scientific Reports Aug 2017The mountain pine beetle (Dendroctonus ponderosae; MPB) is an eruptive bark beetle species affecting pine forests of western North America. MPB are exposed to volatile...
The mountain pine beetle (Dendroctonus ponderosae; MPB) is an eruptive bark beetle species affecting pine forests of western North America. MPB are exposed to volatile monoterpenes, which are important host defense chemicals. We assessed the toxicity of the ten most abundant monoterpenes of lodgepole pine (Pinus contorta), a major host in the current MPB epidemic, against adult MPB from two locations in British Columbia, Canada. Monoterpenes were tested as individual volatiles and included (-)-β-phellandrene, (+)-3-carene, myrcene, terpinolene, and both enantiomers of α-pinene, β-pinene and limonene. Dose-mortality experiments identified (-)-limonene as the most toxic (LC: 32 μL/L), and (-)-α-pinene (LC: 290 μL/L) and terpinolene (LC: >500 μL/L) as the least toxic. MPB body weight had a significant positive effect on the ability to survive most monoterpene volatiles, while sex did not have a significant effect with most monoterpenes. This study helps to quantitatively define the effects of individual monoterpenes towards MPB mortality, which is critical when assessing the variable monoterpene chemical defense profiles of its host species.
Topics: Animals; Coleoptera; Dose-Response Relationship, Drug; Inhibitory Concentration 50; Monoterpenes; Pinus; Plant Extracts
PubMed: 28821756
DOI: 10.1038/s41598-017-08983-y -
Environmental Science & Technology Sep 2017We report novel in situ speciated observations of monoterpenes (α- and β-pinene, myrcene, δ3-carene, ocimene, limonene) in seawater and air during three cruises in...
We report novel in situ speciated observations of monoterpenes (α- and β-pinene, myrcene, δ3-carene, ocimene, limonene) in seawater and air during three cruises in the Arctic and Atlantic Oceans, in/over generally oligotrophic waters. Oceanic concentrations of the individual monoterpenes ranged from below the detection limit of <1 pmol L to 5 pmol L, with average concentrations of between 0.5 and 2.9 pmol L. After careful filtering for contamination, atmospheric mixing ratios varied from below the detection limit (<1 pptv) to 5 pptv, with averages of 0.05-5 pptv; these levels are up to 2 orders of magnitude lower than those reported previously. This could be at least partly due to sampling over waters with much lower biological activity than in previous studies. Unlike in previous studies, no clear relationships of the monoterpenes with biological variables were found. Based on our measured seawater concentrations and a global model simulation, we estimate total global marine monoterpene emissions of 0.16 Tg C yr, similar to a previous bottom-up estimate based on laboratory monoculture studies but 2 orders of magnitude lower than a previous top-down estimate of 29.5 Tg C yr.
Topics: Arctic Regions; Atlantic Ocean; Bridged Bicyclo Compounds; Environmental Monitoring; Monoterpenes
PubMed: 28752764
DOI: 10.1021/acs.est.7b02240 -
Marine Drugs Apr 2019The subtidal red alga was collected from the Western Antarctic Peninsula during the 2011 and 2017 austral summers. Bulk collections from specific sites corresponded to...
The subtidal red alga was collected from the Western Antarctic Peninsula during the 2011 and 2017 austral summers. Bulk collections from specific sites corresponded to chemogroups identified by Young et al. in 2013. One of the chemogroups yielded several known acyclic halogenated monoterpenes (-) as well as undescribed compounds of the same class, anverenes B-D (-). Examination of another chemogroup yielded an undescribed cyclic halogenated monoterpene anverene E () as its major secondary metabolite. Elucidation of structures was achieved through one-dimensional (1D) and 2D nuclear magnetic resonance (NMR) spectroscopy and negative chemical ionization mass spectrometry. Compounds - show moderate cytotoxicity against cervical cancer (HeLa) cells.
Topics: Antarctic Regions; Cell Line, Tumor; Cell Survival; HeLa Cells; Humans; Hydrocarbons, Halogenated; Inhibitory Concentration 50; Molecular Conformation; Monoterpenes; Nuclear Magnetic Resonance, Biomolecular; Plocamium
PubMed: 30999651
DOI: 10.3390/md17040230