Showing papers on "Terpene published in 2015"
TL;DR: A powerful search method based on the use of hidden Markov models (HMMs) and protein families database (Pfam) search that has allowed the discovery of monoterpene synthases of bacterial origin is described.
Abstract: Odoriferous terpene metabolites of bacterial origin have been known for many years. In genome-sequenced Streptomycetaceae microorganisms, the vast majority produces the degraded sesquiterpene alcohol geosmin. Two minor groups of bacteria do not produce geosmin, with one of these groups instead producing other sesquiterpene alcohols, whereas members of the remaining group do not produce any detectable terpenoid metabolites. Because bacterial terpene synthases typically show no significant overall sequence similarity to any other known fungal or plant terpene synthases and usually exhibit relatively low levels of mutual sequence similarity with other bacterial synthases, simple correlation of protein sequence data with the structure of the cyclized terpene product has been precluded. We have previously described a powerful search method based on the use of hidden Markov models (HMMs) and protein families database (Pfam) search that has allowed the discovery of monoterpene synthases of bacterial origin. Using an enhanced set of HMM parameters generated using a training set of 140 previously identified bacterial terpene synthase sequences, a Pfam search of 8,759,463 predicted bacterial proteins from public databases and in-house draft genome data has now revealed 262 presumptive terpene synthases. The biochemical function of a considerable number of these presumptive terpene synthase genes could be determined by expression in a specially engineered heterologous Streptomyces host and spectroscopic identification of the resulting terpene products. In addition to a wide variety of terpenes that had been previously reported from fungal or plant sources, we have isolated and determined the complete structures of 13 previously unidentified cyclic sesquiterpenes and diterpenes.
381 citations
01 Apr 2015
TL;DR: In this review paper, recent developments in the biosynthesis of terpenoids, indepth description of terpene synthases and their phylogenetic analysis, regulation of ter pene biosynthesis as well as updates of ter penes which have entered in the clinical studies are reviewed thoroughly.
Abstract: The terpenoids constitute the largest class of natural products and many interesting products are extensively applied in the industrial sector as flavors, fragrances, spices and are also used in perfumery and cosmetics. Many terpenoids have biological activities and also used for medical purposes. In higher plants, the conventional acetate-mevalonic acid pathway operates mainly in the cytosol and mitochondria and synthesizes sterols, sesquiterpenes and ubiquinones mainly. In the plastid, the non-mevalonic acid pathway takes place and synthesizes hemi-, mono-, sesqui-, and diterpenes along with carotenoids and phytol tail of chlorophyll. In this review paper, recent developments in the biosynthesis of terpenoids, indepth description of terpene synthases and their phylogenetic analysis, regulation of terpene biosynthesis as well as updates of terpenes which have entered in the clinical studies are reviewed thoroughly.
357 citations
TL;DR: This review discusses the relationship between the chemical composition and antioxidant property of peppermint tisane and essential oil and finds that major cyclic oxygenated terpenes (menthol and menthone) are conflicting.
124 citations
109 citations
TL;DR: In this article, principal component analysis (PCA) results from a dataset containing 494 cannabis flower samples and 170 concentrate samples analyzed for 31 compounds were presented and a continuum of chemical composition amongst cannabis strains was found instead of distinct chemotypes.
Abstract: In this paper, we present principal component analysis (PCA) results from a dataset containing 494 cannabis flower samples and 170 concentrate samples analyzed for 31 compounds. A continuum of chemical composition amongst cannabis strains was found instead of distinct chemotypes. Our data shows that some strains are much more reproducible in chemical composition than others. Strains labeled as indica were compared with those labeled as sativa and no evidence was found that these two cultivars are distinctly different chemotypes. PCA of “OG” and “Kush” type strains found that “OG” strains have relatively higher levels of α-terpineol, fenchol, limonene, camphene, terpinolene and linalool where “Kush” samples are characterized mainly by the compounds trans-ocimene, guaiol, β-eudesmol, myrcene and α-pinene. The composition of concentrates and flowers were compared as well. Although the absolute concentration of compounds in concentrates is much higher, the relative composition of compounds between flowers and concentrates is similar.
98 citations
TL;DR: In a striking example of convergent evolution, mutational analysis of this terpene synthase revealed an active site asparagine critical for water capture and specificity during cineole synthesis, the same mechanism used in an unrelated plant homologue.
66 citations
TL;DR: Heterologous expression and detailed NMR spectroscopic analysis allowed assignment of the structures of 13 new cyclic terpenes, two of which were found to be linear triquinane sesquiterpenes that have never previously been isolated from bacteria or any other source.
Abstract: Mining of bacterial genome data has revealed numerous presumptive terpene synthases. Heterologous expression of several putative terpene synthase genes in an engineered Streptomyces host has revealed 13 newly discovered terpenes whose GC-MS and NMR data did not match with any known compounds in spectroscopic databases. Each of the genes encoding the corresponding terpene synthases were silent in their parent microorganisms. Heterologous expression and detailed NMR spectroscopic analysis allowed assignment of the structures of 13 new cyclic terpenes. Among these newly identified compounds, two were found to be linear triquinane sesquiterpenes that have never previously been isolated from bacteria or any other source. The remaining 11 new compounds were shown to be diterpene hydrocarbons and alcohol, including hydropyrene (1), hydropyrenol (2), tsukubadiene (11) and odyverdienes A (12) and B (13) each displaying a novel diterpene skeleton that had not previously been reported.
59 citations
TL;DR: A key role of the floral phyllospheric microbiota is shown in the quantity and quality of floral terpene emissions and therefore a possible key role in pollination.
Abstract: The emission of floral terpenes plays a key role in pollination in many plant species. We hypothesized that the floral phyllospheric microbiota could significantly influence these floral terpene emissions because microorganisms also produce and emit terpenes. We tested this hypothesis by analyzing the effect of removing the microbiota from flowers. We fumigated Sambucus nigra L. plants, including their flowers, with a combination of three broad-spectrum antibiotics and measured the floral emissions and tissular concentrations in both antibiotic-fumigated and non-fumigated plants. Floral terpene emissions decreased by ca. two thirds after fumigation. The concentration of terpenes in floral tissues did not decrease, and floral respiration rates did not change, indicating an absence of damage to the floral tissues. The suppression of the phyllospheric microbial communities also changed the composition and proportion of terpenes in the volatile blend. One week after fumigation, the flowers were not emitting b-ocimene, linalool, epoxylinalool, and linalool oxide. These results show a key role of the floral phyllospheric microbiota in the quantity and quality of floral terpene emissions and therefore a possible key role in pollination.
58 citations
TL;DR: It is inferred that less rainfall and stronger sunshine in the GT region could initiate the earlier expression of ripening-related genes and accelerate the berry maturation, eventually limiting the production of terpene volatiles.
Abstract: Terpenes are of great interest to winemakers because of their extremely low perception thresholds and pleasant floral odors. Even for the same variety, terpene profile can be substantially different for grapevine growing environments. Recently a series of genes required for terpene biosynthesis were biochemically characterized in grape berries. However, the genes that dominate the differential terpene accumulation of grape berries between regions have yet to be identified. Free and glycosidically-bound terpenes were identified and quantified using gas chromatography-mass spectrometry (GC-MS) technique. The transcription expression profiling of the genes was obtained by RNA sequencing and part of the results were verified by quantitative real time PCR (QPCR). The gene co-expression networks were constructed with the Cytoscape software v 2.8.2 (
www.cytoscape.org
). ‘Muscat Blanc a Petits Grains’ berries were collected from two wine-producing regions with strikingly different climates, Gaotai (GT) in Gansu Province and Changli (CL) in Hebei Province in China, at four developmental stages for two consecutive years. GC-MS analysis demonstrated that both free and glycosidically bound terpenes accumulated primarily after veraison and that mature grape berries from CL contained significantly higher concentrations of free and glycosidically bound terpenes than berries from GT. Transcriptome analysis revealed that some key genes involved in terpene biosynthesis were markedly up-regulated in the CL region. Particularly in the MEP pathway, the expression of VviHDR (1-hydroxy-2-methyl-2-butenyl 4-diphosphate reductase) paralleled with the accumulation of terpenes, which can promote the flow of isopentenyl diphosphate (IPP) into the terpene synthetic pathway. The glycosidically bound monoterpenes accumulated differentially along with maturation in both regions, which is synchronous with the expression of a monoterpene glucosyltransferase gene (VviUGT85A2L4 (VviGT14)). Other genes were also found to be related to the differential accumulation of terpenes and monoterpene glycosides in the grapes between regions. Transcription factors that could regulate terpene synthesis were predicted through gene co-expression network analysis. Additionally, the genes involved in abscisic acid (ABA) and ethylene signal responses were expressed at high levels earlier in GT grapes than in CL grapes. Differential production of free and glycosidically-bound terpenes in grape berries across GT and CL regions should be related at least to the expression of both VviHDR and VviUGT85A2L4 (VviGT14). Considering the expression patterns of both transcription factors and mature-related genes, we infer that less rainfall and stronger sunshine in the GT region could initiate the earlier expression of ripening-related genes and accelerate the berry maturation, eventually limiting the production of terpene volatiles.
58 citations
TL;DR: A transcriptome-based identification and functional characterization of two carrot terpene synthases suggest a role for DcTPS genes in carrot aroma biosynthesis.
Abstract: Plants produce an excess of volatile organic compounds, which are important in determining the quality and nutraceutical properties of fruit and root crops, including the taste and aroma of carrots (Daucus carota L.). A combined chemical, biochemical, and molecular study was conducted to evaluate the differential accumulation of volatile terpenes in a diverse collection of fresh carrots (D. carota L.). Here, we report on a transcriptome-based identification and functional characterization of two carrot terpene synthases, the sesquiterpene synthase, DcTPS1, and the monoterpene synthase, DcTPS2. Recombinant DcTPS1 protein produces mainly (E)-β-caryophyllene, the predominant sesquiterpene in carrot roots, and α-humulene, while recombinant DcTPS2 functions as a monoterpene synthase with geraniol as the main product. Both genes are differentially transcribed in different cultivars and during carrot root development. Our results suggest a role for DcTPS genes in carrot aroma biosynthesis.
54 citations
TL;DR: The chemical constituents of Spirogyra longata, successively extracted with petroleum ether, methylene chloride, chloroform, acetone and methanol were determined by GC-MS.
TL;DR: The first discovery of an epistatic network of residues that controls the onset of terpene cyclization in Artemisia annua is reported, and it is found one dominant mutation is sufficient to activate cyclization, and together with two additional residues comprise a network of strongly epistatic interactions that activate, suppress or reactivate cyclization.
Abstract: The emergence of terpene cyclization was critical to the evolutionary expansion of chemical diversity yet remains unexplored. Here we report the first discovery of an epistatic network of residues that controls the onset of terpene cyclization in Artemisia annua. We begin with amorpha-4,11-diene synthase (ADS) and (E)-b-farnesene synthase (BFS), a pair of terpene synthases that produce cyclic or linear terpenes, respectively. A library of B27,000 enzymes is generated by breeding combinations of natural amino-acid substitutions from the cyclic into the linear producer. We discover one dominant mutation is sufficient to activate cyclization, and together with two additional residues comprise a network of strongly epistatic interactions that activate, suppress or reactivate cyclization. Remarkably, this epistatic network of equivalent residues also controls cyclization in a BFS homologue from Citrus junos. Fitness landscape analysis of mutational trajectories provides quantitative insights into a major epoch in specialized metabolism.
TL;DR: In this paper, the fatty acid composition and volatile compounds of selected traditional Macedonian edible oils of several varieties, including sunflower seeds, pumpkin seeds, flax seed, rapeseed and sesame seeds, were analyzed.
TL;DR: This chapter provides an overview of terpenoid hydroxylation reactions catalyzed by bacterial P450s and highlights the achievements made by protein engineering to establish productive hydroxymation processes.
Abstract: Terpenoids comprise a highly diverse group of natural products. In addition to their basic carbon skeleton, they differ from one another in their functional groups. Functional groups attached to the carbon skeleton are the basis of the terpenoids' diverse properties. Further modifications of terpene olefins include the introduction of acyl-, aryl-, or sugar moieties and usually start with oxidations catalyzed by cytochrome P450 monooxygenases (P450s, CYPs). P450s are ubiquitously distributed throughout nature, involved in essential biological pathways such as terpenoid biosynthesis as well as the tailoring of terpenoids and other natural products. Their ability to introduce oxygen into nonactivated C-H bonds is unique and makes P450s very attractive for applications in biotechnology. Especially in the field of terpene oxidation, biotransformation methods emerge as an attractive alternative to classical chemical synthesis. For this reason, microbial P450s depict a highly interesting target for protein engineering approaches in order to increase selectivity and activity, respectively. Microbial P450s have been described to convert industrial and pharmaceutically interesting terpenoids such as ionones, limone, valencene, resin acids, and triterpenes (including steroids) as well as vitamin D3. Highly selective and active mutants have been evolved by applying classical site-directed mutagenesis as well as directed evolution of proteins. As P450s usually depend on electron transfer proteins, mutagenesis has also been applied to improve the interactions between P450s and their respective redox partners. This chapter provides an overview of terpenoid hydroxylation reactions catalyzed by bacterial P450s and highlights the achievements made by protein engineering to establish productive hydroxylation processes.
01 Jan 2015
TL;DR: Terpene biosynthesis in prokaryotes, fungi, and plants, and directed evolution of genes and enzymes for isoprenoid metabolic engineering are studied.
Abstract: Terpene biosynthesis in prokaryotes.- Terpene biosynthesis in fungi.- Terpene biosynthesis in plants.- Terpene synthases: functions, evolution, and engineering.- (Plant) P450s for terpene functionalization.- Terpene hydroxylation / cyclization with engineered microbial enzymes.- Directed evolution of genes and enzymes for isoprenoid metabolic engineering.- Advances in the analysis of isoprenoid metabolites.- Metabolic engineering of bacterial and yeast microbial platform strains for isoprenoid production.- Metabolic engineering of algae, mosses, and higher plants for terpenoid production.- Bioprocess engineering for synthesis and conversion of isoprenoids.- Isoprene.- Menthol and related monoterpenes.- Monterpene indole alkaloids.- Farnesene and other isoprenoid biofuels.- Valencene and Nootkatone.- Santalenes and Santalols.- Sclareol and ambroxide related diterpenes.- Taxol.- Carotenoids.
TL;DR: Nerolidol and terpinolene significantly reduced sclerotia production, while α-pinene stimulated it in a concentration-dependent manner, and were the most abundant with antifungal activity against S. cepivorum.
TL;DR: This study used photo-induced thiol-ene reactions to design bio-based cross-linked networks from diallyl derivative isosorbide, a crude monoterpene as linalool and a trithiol to prepare new antibacterial UV-cured networks by using a thiol -ene formulation with covalent immobilization of monoterpenes as antibacterial agents and without any organic solvent thanks to the solvent-like properties of linalools.
Abstract: In this study, we used photo-induced thiol-ene reactions to design bio-based cross-linked networks from diallyl derivative isosorbide, a crude monoterpene as linalool and a trithiol. The aim of this study is to prepare new antibacterial UV-cured networks by using a thiol-ene formulation with covalent immobilization of monoterpenes as antibacterial agents and without any organic solvent thanks to the solvent-like properties of linalool. The challenge was to demonstrate the advantage of using linalool as a chemical platform molecule and, at the same time, as an antibacterial agent. The incorporation of linear linalool to the rigid isosorbide moiety generates flexible networks. Different networks were prepared by varying the mass ratio of linalool (from 0 to 100% w/w) mixed into the coating and then characterized. Their antibacterial activities were investigated in vitro against two pathogenic bacteria strains: Escherichia coli and Staphylococcus aureus. The results have shown a promising antiadherence for S...
TL;DR: In this article, a reverse genetics approach was used to isolate full-length rice terpene synthase 20 (OsTPS20, 599 amino acids, 69.39 kDa), which was further characterized as an (S)-limonene synth enzyme by removing the Nterminal signal peptide (63 amino acids) of the protein.
Abstract: This study examined the volatile terpenes produced by rice seedlings in response to oxidative stress induced by various abiotic factors. Solid-phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS) analyses revealed that when exposed to UV-B radiation, rice seedlings emitted a bouquet of monoterpene mixtures in a time-dependent manner. The mixtures comprised limonene, sabinene, myrcene, α-terpinene, β-ocimene, γ-terpinene, and α-terpinolene. Among them, (S)-limonene was the most abundant volatile, discriminated by chiral SPME–GC–MS. The volatile profiles collected from rice plants treated with both γ-irradiation and H2O2 were identical to those observed in the UV-B irradiated plants, thus indicating that the volatile mixtures were specifically produced in response to oxidative stress, particularly in the presence of H2O2. Using a reverse genetics approach, we isolated full-length rice terpene synthase 20 (OsTPS20, 599 amino acids, 69.39 kDa), which was further characterized as an (S)-limonene synthase by removing the N-terminal signal peptide (63 amino acids) of the protein. The recombinant OsTPS20 protein catalyzed the conversion of geranyl diphosphate to (S)-limonene and other minor monoterpenes, essentially covering all of the volatile compounds detected from the plant. Moreover, qRT-PCR revealed that the transcript levels of OsTPS20 were significantly induced in response to oxidative stress, thereby suggesting that OsTPS20 plays a major role in producing terpene volatiles during abiotic stress. Detailed biochemical analyses and the unusual domain characteristics of OsTPS20 are also discussed in this report.
TL;DR: Results suggest that the fruits of P. mume could be an excellent source of anti-osteoporosis phytochemicals that may be developed as natural nutraceuticals and functional foods.
Abstract: The fruits of Prunus mume are a common commercial product and a valuable source of food and medicinal material in Eastern Asian countries. Our phytochemical investigation of the P. mume fruit led to the isolation of nine terpenes, including three ursane-type triterpenes (1–3), two cycloartane-type triterpenes (4 and 5), and four tocopherols (10–13), as well as four sterols (6–9). Their structures were elucidated based on extensive spectroscopic analysis, including 1D and 2D NMR and ESI-MS, and the majority of these compounds were isolated from this plant for the first time. The anti-osteoporosis activities of 1–13 were evaluated by measuring their inhibitory effects on tartrate-resistant acid phosphatase (TRAP) activity in receptor activator of nuclear factor κB ligand-induced osteoclastic RAW 264.7 macrophage cells. Compounds 2–7 and 9–12 significantly suppressed TRAP activity down to 47.96 ± 2.45–86.45 ± 3.07 % relative to the control at a concentration of 1 μM. These results suggest that the fruits of P. mume could be an excellent source of anti-osteoporosis phytochemicals that may be developed as natural nutraceuticals and functional foods.
TL;DR: Electron paramagnetic resonance (EPR) spectroscopy was used in a detailed study of the interactions of several terpenes with DPPC membranes, finding that Nerolidol, which had the highest octanol-water partition coefficient, generated the highest amount of spin label extraction.
TL;DR: Biotransformation experiments confirmed the applicability of the novel GTs in biocatalytic processes for the production of these novel compounds, and predicted that terpene glucosides will become commercially available for food, cosmetic, and pharmaceutical industry due to improved biocatsynthetic processes involving GT enzymes.
Abstract: Terpenoids are one of the main classes of natural products. In plants, a large fraction of the terpenoids is present as nonvolatile glycosides. The terpene glycosides have attracted much attention as antimicrobials, flavor precursors, and detergents. They are either extracted from plant materials or are synthesized by chemical and biocatalytic methods. Up to now, biotechnological production of terpene glycosides is based on reversed hydrolysis performed by glycosidases. However, this method suffers from low yields as a matter of principle. Recently, the first uridine diphosphate-glucose:monoterpenol β-d-glucosyltransferase (GT) genes were cloned and characterized from grapevine (Vitis vinifera) and kiwi (Actinidia deliciosa). Heterologous expression in Escherichia coli yielded promiscuous GT enzymes that efficiently glucosylated primary monoterpenols, simple alcohols, and phenols. The GT enzymes differed in substrate preference and activity toward their terpenoid substrates. Biotransformation experiments confirmed the applicability of the novel GTs in biocatalytic processes for the production of these novel compounds. In the near future, terpene glucosides will become commercially available for food, cosmetic, and pharmaceutical industry due to improved biocatalytic processes involving GT enzymes.
TL;DR: The seed and cone essential oils of both firs exhibited DPPH‐radical‐scavenging properties and low antibacterial activity against the bacterial strains tested, and evoked only low cytotoxicity towards normal fibroblasts and the two cancer cell lines.
Abstract: The chemical composition, including the enantiomeric excess of the main terpenes, the antimicrobial and antiradical activities, as well as the cytotoxicity of Abies alba and A. koreana seed and cone essential oils were investigated. Additionally, their seed hydrolates were characterized. In the examined oils and hydrolates, a total of 174 compounds were identified, which comprised 95.6-99.9% of the volatiles. The essential oils were mainly composed of monoterpene hydrocarbons, whereas the composition of the hydrolates, differing from the seed oils of the corresponding fir species, consisted mainly of oxygenated derivatives of sesquiterpenes. The seed and cone essential oils of both firs exhibited DPPH-radical-scavenging properties and low antibacterial activity against the bacterial strains tested. Moreover, they evoked only low cytotoxicity towards normal fibroblasts and the two cancer cell lines MCF-7 and MDA-MBA-231. At concentrations up to 50 μg/ml, all essential oils were safe in relation to normal fibroblasts. Although they induced cytotoxicity towards the cancer cells at concentrations slightly lower than those required for the inhibition of fibroblast proliferation, their influence on cancer cells was weak, with IC50 values similar to those observed towards normal fibroblasts.
TL;DR: In this article, the authors examined the possible effects of common monoterpenes and higher terpenes on the activity of enzymes crucial in C, N, P, S cycling, i.e. β-glucosidase, chitinase, protease, acid phosphatase and arylsulfatase.
Abstract: Plant secondary compounds, including terpenes, potentially play an important role in controlling the decomposition process in boreal forest soil. However, the role of terpenes is not well understood, and their direct influence on enzyme activity is not well-known. The aim of this study was to examine the possible effects of common monoterpenes and higher terpenes on the activity of enzymes crucial in C, N, P, S cycling, i.e. β-glucosidase, chitinase, protease, acid phosphatase and arylsulfatase. Monoterpenes (α-pinene, carene, myrcene), diterpenes (abietic acid and colophony), and triterpene (β-sitosterol) were used. Studies were done in two environments, in vitro (studies without soil) and in vivo (studies with soil). Soil experiments were conducted using humus layers of two different birch stands, the first N-poor with high organic matter content and the second N-rich with a lower organic matter content. In general, all the terpenes studied showed inhibitory potential against enzymes in in vitro studies. In the soil incubation studies, both of the measured enzymes, chitinase and β-glucosidase, showed some decrease in activity when exposed to different terpenes. Our study suggests that terpenes modify the enzyme machinery in boreal forest soil.
TL;DR: Through these examples, it is shown how modern computational quantum chemistry can be employed as an effective tool for assessing the validity of proposed mechanisms for terpene/terpenoid formation.
Abstract: Computational chemistry approaches for studying the formation of terpenes/terpenoids in wines are presented, using five particular terpenes/terpenoids (1,8-cineole, α-ylangene, botrydial, rotundone, and the wine lactone), volatile compounds (or their precursors) found in wine and/or wine grapes, as representative examples. Through these examples, we show how modern computational quantum chemistry can be employed as an effective tool for assessing the validity of proposed mechanisms for terpene/terpenoid formation.
TL;DR: In this paper, hydrous pyrolysis was used to artificially mature leaves from four plant species, including the deciduous angiosperms Acer rubrum and Platanus occidentalis, Taxodium distichum and the evergreen conifer Pinus sylvestris.
01 Jan 2015
TL;DR: The present review will highlight the chemical constituents and the pharmacological and therapeutic effects of Artemisia campestris.
Abstract: Artemisia campestris contained alkaloids, saponins, terpenes and flavonoids. The hydrodistilled essential oil of fresh aerial parts of Artemisia campestris contained β-myrcene (16.47%), α-pinene (14.18 %), trans-β- ocimene (12.61%), β-cymene (8.15%) and camphor(5.85%). A. campestris, revealed several pharmacological activities such as antimicrobial, antioxidant, cytotoxic, insecticidal, antivenomous and many other pharmacological effects. The present review will highlight the chemical constituents and the pharmacological and therapeutic effects of Artemisia campestris.
Journal Article•
TL;DR: Five main constituents, camphene, iso-artemisia ketone, 1-camphor, β-carophyllene, and β-pinene were identified from the volatile oil of this herb.
Abstract: Six crystalline components were isolated from the lipophilic fraction of Artemisia annua L. They have been identified as four sesquiterpenes, one flavonol and one coumarin. Qinghaosu I and III are new sesquiterpenes. Five main constituents, camphene, iso-artemisia ketone, 1-camphor, β-carophyllene, and β-pinene were identified from the volatile oil of this herb.
TL;DR: In this paper, a high-performance liquid chromatographic (HPLC) method using a post-column reaction to produce chemiluminescence via luminol oxidation was developed to address the need for a species-differentiating method.
Abstract: Limonene and linalool are unsaturated terpenes commonly found as major components in many essential oils, and both are easily oxidized by atmospheric oxygen to form hydroperoxides. The hydroperoxides of both limonene and linalool are known to be sensitizers capable of causing allergic contact dermatitis, but with different potency. In addition, positional isomers of limonene hydroperoxide have been demonstrated to have different allergenic potencies. This creates a need for an analytical method that is capable of differentiating hydroperoxides derived from different terpenes, including the various positional isomers. The standard iodometric titration methods [peroxide value (POV) methods] typically used to measure hydroperoxide levels in essential oils provide only a total level of all oxidizing species, including hydroperoxides. These POV methods are not capable of species differentiation and therefore may not reliably correlate well with the skin sensitizing potency of a particular sample. A high-performance liquid chromatographic (HPLC) method using a post-column reaction to produce chemiluminescence via luminol oxidation was developed to address the need for a species-differentiating method. Copyright © 2015 John Wiley & Sons, Ltd.
TL;DR: The study indicated that these novel derivatives can find useful application in control of food-related pathogenic microbes in foods by being more effective in their antimicrobial action than the corresponding parent compounds.
TL;DR: Several of the new compounds presented better anti-inflammatory effect and lower cytotoxicity than the parent terpenes and showed better effects in the TPA assay, with best activity for 6, 12 and 15.
Abstract: The aim of the study was to assess changes in the activity of anti-inflammatory terpenes from Chilean medicinal plants after the formation of derivatives incorporating synthetic anti-inflammatory agents. Ten new hybrid molecules were synthesized combining terpenes (ferruginol (1), imbricatolic acid (2) and oleanolic acid (3)) with ibuprofen (4) or naproxen (5). The topical anti-inflammatory activity of the compounds was assessed in mice by the arachidonic acid (AA) and 12-O-tetradecanoyl phorbol 13-acetate (TPA) induced ear edema assays. Basal cytotoxicity was determined towards human lung fibroblasts, gastric epithelial cells and hepatocytes. At 1.4 µmol/mouse, a strong anti-inflammatory effect in the TPA assay was observed for oleanoyl ibuprofenate 12 (79.9%) and oleanoyl ibuprofenate methyl ester 15 (80.0%). In the AA assay, the best activity was observed for 12 at 3.2 µmol/mouse, with 56.8% reduction of inflammation, in the same range as nimesulide (48.9%). All the terpenyl-synthetic anti-inflammatory hybrids showed better effects in the TPA assay, with best activity for 6, 12 and 15. The cytotoxicity of the compounds 8 and 10 with a free COOH, was higher than that of 2. The derivatives from 3 were less toxic than the triterpene. Several of the new compounds presented better anti-inflammatory effect and lower cytotoxicity than the parent terpenes.