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Molecules (Basel, Switzerland) Jan 2024Monoterpenes and meroterpenes are two large classes of isoprene-based molecules produced by terrestrial plants and unicellular organisms as diverse secondary... (Review)
Review
Monoterpenes and meroterpenes are two large classes of isoprene-based molecules produced by terrestrial plants and unicellular organisms as diverse secondary metabolites. The global rising incidence of cancer has led to a renewed interest in natural products. These monoterpenes and meroterpenes represent a novel source of molecular scaffolds that can serve as medicinal chemistry platforms for the development of potential preclinical leads. Furthermore, some of these natural products are either abundant, or their synthetic strategies are scalable as it will be indicated here, facilitating their derivatization to expand their scope in drug discovery. This review is a collection of representative updates (from 2016-2023) in biologically active monoterpene and meroterpenoid natural products and focuses on the recent findings of the pharmacological potential of these bioactive compounds as well as the newly developed synthetic strategies employed to access them. Particular emphasis will be placed on the anticancer and antioxidant potential of these compounds in order to raise knowledge for further investigations into the development of potential anti-cancer therapeutics. The mounting experimental evidence from various research groups across the globe regarding the use of these natural products at pre-clinical levels, renders them a fast-track research area worth of attention.
Topics: Antioxidants; Biological Products; Antineoplastic Agents; Monoterpenes; Biology
PubMed: 38202861
DOI: 10.3390/molecules29010279 -
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 -
Biodegradation Feb 2019The betaproteobacterium Castellaniella defragrans 65Phen grows on monoterpenes at concentrations toxic to many bacteria. Tolerance mechanisms include modifications of...
The betaproteobacterium Castellaniella defragrans 65Phen grows on monoterpenes at concentrations toxic to many bacteria. Tolerance mechanisms include modifications of the membrane fatty acid composition and the mineralization of monoterpenes. In this study, we characterized an efflux transporter associated to the monoterpene metabolism. The inner-membrane transporter AmeD (apolar monoterpene efflux) affiliated to the HAE3 (hydrophobe/amphiphile efflux) family within the Resistance-Nodulation-Division (RND) superfamily. RND pumps of the HAE3 family are known for transporting substrates into the periplasm. AmeD is co-expressed with the outer membrane protein AmeA and the periplasmic proteins AmeB and AmeC, suggesting an export channel into the environment similar to HAE1-type RND exporters. Proteins AmeABCD are encoded within a genetic island involved in the metabolism of acyclic and cyclic monoterpenes. The deletion of ameABCD translated into a decrease in tolerance to monoterpenes in liquid cultures. The addition of acetate as cosubstrate in limonene-containing cultures partially alleviated monoterpene toxicity in the deletion mutant. Accumulation of Nile Red in cells of C. defragrans required dissipation of the proton motive force with carbonyl cyanide m-chlorophenylhydrazone (CCCP). Cells lacking AmeABCD accumulated more Nile Red, suggesting an export function of the proteins. Our observations suggest that the tetrapartite RND transporter AmeABCD acts as an exporter during monoterpene detoxification in C. defragrans.
Topics: Bacterial Proteins; Biodegradation, Environmental; Computer Simulation; Likelihood Functions; Membrane Transport Proteins; Monoterpenes; Multigene Family; Phylogeny; Proteobacteria
PubMed: 30334144
DOI: 10.1007/s10532-018-9857-6 -
PloS One 2024Monoterpenes are a large class of naturally occurring fragrant molecules. These chemicals are commonly used in olfactory studies to survey neural activity and probe the...
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 β-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.
Topics: Mice; Animals; Limonene; Mice, Inbred C57BL; Monoterpenes; Bicyclic Monoterpenes; Acyclic Monoterpenes; Cyclohexane Monoterpenes
PubMed: 38394306
DOI: 10.1371/journal.pone.0298448 -
Tree Physiology Jul 2020Monoterpenes are important components of plant essential oils and have long been used as raw materials for spices and food flavorings. A number of studies have been...
Monoterpenes are important components of plant essential oils and have long been used as raw materials for spices and food flavorings. A number of studies have been performed to increase the content of monoterpenes in plants, but no obvious effect was observed. Exchange was observed between the methylerythritol phosphate (MEP) and mevalonic acid (MVA) metabolic pathways, which produce monoterpenes and sesquiterpenes, respectively. However, the specific details of the communication have not been elucidated. In the present study, we investigated the effects of overexpressing Litsea cubeba (Lour.) Persoon 3-hydroxy-3-methylglutaryl-coenzyme A synthase (LcHMGS) on the production of monoterpenes and sesquiterpenes. In addition, we also explored the flow of metabolic flux between the MEP and MVA pathways. We cloned LcHMGS and analyzed its expression pattern in various tissues. The overexpression of LcHMGS significantly increased the species and content of monoterpenes and sesquiterpenes. In addition, LcHMGS overexpression in plants induced such phenotypes as excessive growth, enlarged vegetative organs and early flowering by elevating the GA3 content. Our results demonstrate a metabolic engineering strategy to improve the yield of monoterpenes and sesquiterpenes and simultaneously increase the biomass of plants.
Topics: Acyl Coenzyme A; Monoterpenes; Oils, Volatile; Sesquiterpenes
PubMed: 32325486
DOI: 10.1093/treephys/tpaa045 -
Critical Reviews in Food Science and... 2023Monoterpenes are important flavor and fragrance compounds in food. In beer, the monoterpenes mainly come from hops added during boiling process. Biotransformations of...
Monoterpenes are important flavor and fragrance compounds in food. In beer, the monoterpenes mainly come from hops added during boiling process. Biotransformations of monoterpene which occurred during fermentation conferred beer with various kinds of aroma profiles, which can be mainly attributed to the contribution of enzymes in yeast. However, there are few reports on the identification and characterization of these enzymes in yeast. Illustrating the structure and functions of key enzymes related to transformations will broaden their potential applications in beer or other foodstuffs. Monoterpenoids including terpene hydrocarbons (limonene, myrcene, and pinene) and terpene alcohol (linalool, geraniol, nerol, and citronellol) gave the beer flower-like or fruit-like aroma. The biotransformation of monoterpenes and monoterpene alcohols in bacteria and yeast, and potential enzymes related to the transformation of them are reviewed here. Enzymes primarily are dehydrogenases including linalool dehydrogenase/isomerase, geraniol/geranial dehydrogenase, nerol dehydrogenase and citronellol dehydrogenase. Most of them are substrate-specific or substrate-specific after modifications by biotechnology methods, and part of them have been expressed in , while the purification and catalytic rate is very low. Efforts should be made to acquire abundant enzymes, and to fabricate enzyme-expressing yeast, which can be further applied in beer fermentation system.highlightsMonoterpenoids contributed to the flavor of food, especially beer.Transformation of monoterpenoids occurred during fermentation.Various kinds of enzymes are involved in the transformation of monoterpenoids in bacteria, yeast, etc.Crystal structures of these enzymes have been partially resolved.Few enzymes are further applied in food system to obtain abundant flavor.
Topics: Monoterpenes; Beer; Saccharomyces cerevisiae; Escherichia coli; Terpenes; Alcohols; Oxidoreductases
PubMed: 34459289
DOI: 10.1080/10408398.2021.1970510 -
Natural Product Research May 2022Monoterpene derivatives are of great biological relevance in the pharmaceutical industry. In the present study, pyrrolidine derivative of a carvotacetone,...
Monoterpene derivatives are of great biological relevance in the pharmaceutical industry. In the present study, pyrrolidine derivative of a carvotacetone, 3-benzylcarvotacetone (), and selected monoterpenes (3-hydroxy-2-isopropyl-5-methyl--benzoquinone () and piperitol ()) were prepared to provide ()-1-(4-(benzyloxy)-5-isopropyl-2-methylcyclohexa-1,3-dien-1-yl)-pyrrolidine (), 2-isopropyl-5-methyl-3,6-dioxocyclohexa-1,4-dien-1-yl acetate (), 3-hydroxypiperitone () and carvacrol (). Structure of was determined based on NMR and HRMS spectral data. Compound exhibited activity against fungi with an IC value of < 0.8µg/mL. In addition, this compound had an IC value of 14.97µg/mL against methicillin resistant bacteria. Previous to the current study, both compound and had been reported to have anti-microbial and anti-fungal activities.
Topics: Anti-Bacterial Agents; Cyclohexanones; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Monoterpenes; Pyrrolidines
PubMed: 33103456
DOI: 10.1080/14786419.2020.1833201 -
Zeitschrift Fur Naturforschung. C,... May 2022Monoterpenes, a class of isoprenoid compounds, are extensively used in flavor, fragrance, perfumery, and cosmetics. They display many astonishing bioactive properties of...
Monoterpenes, a class of isoprenoid compounds, are extensively used in flavor, fragrance, perfumery, and cosmetics. They display many astonishing bioactive properties of biological and pharmacological significance. All monoterpenes are derived from universal precursor geranyl diphosphate. The demand for new monoterpenoids has been increasing in flavor, fragrances, perfumery, and pharmaceuticals. Chemical methods, which are harmful for human and the environment, synthesize most of these products. Over the years, researchers have developed alternative methods for the production of newer monoterpenoids. Microbial biotransformation is one of them, which relied on microbes and their enzymes. It has produced many new desirable commercially important monoterpenoids. A growing number of reports reflect an ever-expanding scope of microbial biotransformation in food and aroma industries. Simultaneously, our knowledge of the enzymology of monoterpene biosynthetic pathways has been increasing, which facilitated the biotransformation of monoterpenes. In this article, we have covered the progress made on microbial biotransformation of commercial monoterpenes with a brief introduction to their biosynthesis. We have collected several reports from authentic web sources, including Google Scholar, Pubmed, Web of Science, and Scopus published in the past few years to extract information on the topic.
Topics: Biosynthetic Pathways; Biotransformation; Humans; Monoterpenes; Terpenes
PubMed: 34881551
DOI: 10.1515/znc-2021-0192 -
International Journal of Molecular... May 2023Flower scent is one of the main ornamental characteristics of herbaceous peony, and the improvement of flower fragrance is a vital objective of herbaceous peony...
Flower scent is one of the main ornamental characteristics of herbaceous peony, and the improvement of flower fragrance is a vital objective of herbaceous peony breeding. In this study, 87 herbaceous peony cultivars were divided into three groups (no/light fragrance, medium fragrance, and strong fragrance) based on their sensory evaluation scores, and 16 strong fragrance cultivars and one no fragrance cultivar were selected for subsequent analysis. Sixty-eight volatile components were detected in these 17 cultivars based on solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS), and 26 types were identified as important scent components. They were composed of terpenoids, benzenoids/phenylpropanoids, and fatty acid derivatives. According to the content and odor threshold of these main aroma components, the characteristic aroma substances of herbaceous peony were identified, including linalool, geraniol, citronellol, and phenylethyl alcohol (2-PE). The cultivars of strong scented herbaceous peony were divided into three types: rose scent, lily scent, and mixed scent. We explored the possible key genes of characteristic aroma substances in herbaceous peony petals with different odors through the qRT-PCR. The key genes encoding monoterpene biosynthesis were found to be , , , , and . In addition, the linalool synthase (LIS) gene and the geraniol synthase (GES) gene were also found. , and related to the biosynthesis of 2-PE were detected, and the synthetic pathway of 2-PE was speculated. In conclusion, these findings revealed that the difference in gene expression of monoterpene and 2-PE synthesis pathway was related to the difference in the fragrance of herbaceous peony. This study explored the releasing pathway of herbaceous peony characteristic aroma substances and provided key genetic resources for fragrance improvement.
Topics: Odorants; Paeonia; Plant Breeding; Flowers; Monoterpenes
PubMed: 37298360
DOI: 10.3390/ijms24119410 -
Chemistry & Biodiversity Jul 2018Callistrilones F - K (1 - 6), six new triketone-phloroglucinol-monoterpene hybrids were isolated from the twigs and leaves of Callistemon rigidus. Their structures with...
Callistrilones F - K (1 - 6), six new triketone-phloroglucinol-monoterpene hybrids were isolated from the twigs and leaves of Callistemon rigidus. Their structures with absolute configurations were established by a combination analysis of NMR spectra, X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compounds 3 and 4 exhibited moderate inhibitory activities against herpes simplex virus (HSV-1) with IC values of 10.00 ± 2.50 and 12.50 ± 1.30 μm, respectively.
Topics: Antiviral Agents; Dose-Response Relationship, Drug; Ketones; Microbial Sensitivity Tests; Molecular Conformation; Monoterpenes; Myrtaceae; Phloroglucinol; Simplexvirus; Stereoisomerism; Structure-Activity Relationship
PubMed: 29806969
DOI: 10.1002/cbdv.201800172