Terpenes

Terpenes and sterols are complex molecules synthesized by equally complex biosynthetic pathways. Recent progress in using the tools of genetics, molecular genetics and genetic engineering to dissect triterpene metabolism in the cytosol, and terpene metabolism in the ...

The chromatographic separation of a methylene chloride extract of Artemisia rubripes led to the isolation of a new sesquiterpene lactone (3), together with four known compounds, a coumarin (2) and three terpenes (1, 4, and 5). Their structures were characterized to be 1beta,6alpha-dihydroxy-4(15)-eudesmene (1), scopoletin (2), 1alpha,4beta-dihydroxy-8alpha-acetoxy-guaia-2,10(14), 11(13)-triene-6,12-olide (3), 1alpha,4beta-dihydroxy-8alpha-acetoxy-guaia-2,9,11(13)-triene-6,12-olide (4), and beta-sitosterol-3-O-beta-D-glycoside (5) by spectroscopic means.

Osteoarthritis is a progressive joint disease and a major cause of disability for which no curative therapies are yet available. To identify compounds with potential anti-osteoarthritic properties, in this study, we screened one sesquiterpene, E-caryophyllene, and two monoterpene, myrcene and limonene, hydrocarbon compounds for anti-inflammatory, anti-catabolic and pro-anabolic activities in human chondrocytes. At non-cytotoxic concentrations, myrcene and limonene inhibited IL-1β-induced nitric oxide production (IC50=37.3μg/ml and 85.3µg/ml, respectively), but E-caryophyllene was inactive. Myrcene, and limonene to a lesser extent, also decreased IL-1β-induced NF-κB, JNK and p38 activation and the expression of inflammatory (iNOS) and catabolic (MMP-1 and MMP-13) genes, while increasing the expression of anti-catabolic genes (TIMP-1 and -3 by myrcene and TIMP-1 by limonene). Limonene increased ERK1/2 activation by 30%, while myrcene decreased it by 26%, relative to IL-1β-treated cell...

The oral availability of many drugs metabolised by the enzyme cytochrome P(450) 3A4 (CYP3A4) is increased if co-administered with grapefruit juice. Extracts from grapefruit peel have also demonstrated inhibitory activity and, during commercial manufacturing of grapefruit juice, inhibitory components might be squeezed into the juice from the peel. Thus, the aim of this in vitro study was to identify CYP3A4 inhibitors in grapefruit peel. Grapefruit peel was extracted with diethyl ether, and the extract was further fractionated by normal-phase chromatography. Fractions demonstrating significant CYP3A4 inhibitory activity, as measured by the relative reduction in N-demethylation of diltiazem in transfected human liver epithelial cells, were subsequently separated by preparative thin-layer chromatography. Constituents of the fractions and isolated compounds were identified by nuclear magnetic resonance spectroscopy. Analysis of diltiazem and N-demethyl-diltiazem was performed using high-...

Five new meroterpenoids, purpurogenolides A-E (1-5), and four known metabolites (6-9) were isolated from the solid substrate fermentation cultures of the fungus Penicillium purpurogenum MHz 111. The structures of the new meroterpenoids were elucidated by analysis of spectroscopic and spectrometric data (1D and 2D NMR, IR, and HRESIMS). The absolute configurations of 1 and 5 were determined by single-crystal X-ray crystallographic analysis, and those of 2-4 were elucidated on the basis of experimental and calculated electronic circular dichroism spectra. Compounds 2-4 and 6 showed inhibition of nitric oxide production in lipopolysaccharide-activated BV-2 microglial cells with IC50 values of 0.8-30.0 μM.

Fungi (Ascomycota and Basidiomycota) are prolific producers of structurally diverse terpenoid compounds.
Classes of terpenoids identified in fungi include the sesqui-, di- and triterpenoids. Biosynthetic pathways and
enzymes to terpenoids from each of these classes have been described. These typically involve the scaffold
generating terpene synthases and cyclases, and scaffold tailoring enzymes such as e.g. cytochrome P450
monoxygenases, NAD(P)+ and flavin dependent oxidoreductases, and various group transferases that generate
the final bioactive structures. The biosynthesis of several sesquiterpenoid mycotoxins and bioactive diterpenoids
has been well-studied in Ascomycota (e.g. filamentous fungi). Little is known about the terpenoid biosynthetic
pathways in Basidiomycota (e.g. mushroom forming fungi), although they produce a huge diversity of
terpenoid natural products. Specifically, many trans-humulyl cation derived sesquiterpenoid natural products
with potent bioactivities have been isolated. Biosynthetic gene clusters responsible for the production of transhumulyl
cation derived protoilludanes, and other sesquiterpenoids, can be rapidly identified by genome
sequencing and bioinformatic methods. Genome mining combined with heterologous biosynthetic pathway
refactoring has the potential to facilitate discovery and production of pharmaceutically relevant fungal terpenoids.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Thermal effects occurring in ultrahigh-pressure liquid chromatography
(UHPLC) and low-density supercritical fluid chromatography (SFC) have
a negative impact on chromatographic performance, because peaks
broaden and get distorted. A solution to this problem is to thermally
insulate the chromatographic column. A strict adiabatic environment can
be achieved by embedding the whole chromatographic column in a large
vacuum chamber, itself connected to a turbomolecular pump that delivers
a high vacuum. From a practical viewpoint, this prototype research
apparatus is costly, its assembly is time-consuming, and it is complex.
Consequently, it is not adapted to routine analyses in standard analytical
laboratories. Therefore, a new approach, using vacuum-jacketed column
technology, has been developed to cope with these practical limitations.
The applications and advantages of this new technology relative to
standard columns are presented and discussed for both UHPLC and SFC
separations operated under extreme conditions.

ABSTRACTThis study examined the effect of subinhibitoryMelaleuca alternifolia(tea tree) essential oil on the development of antibiotic resistance inStaphylococcus aureusandEscherichia coli. Frequencies of single-step antibiotic-resistant mutants were determined by inoculating bacteria cultured with or without subinhibitory tea tree oil onto agar containing 2 to 8 times the MIC of each antibiotic and with or without tea tree oil. Whereas most differences in resistance frequencies were relatively minor, the combination of kanamycin and tea tree oil yielded approximately 10-fold fewer resistantE. colimutants than kanamycin alone. The development of multistep antibiotic resistance in the presence of tea tree oil or terpinen-4-ol was examined by culturingS. aureusandE. coliisolates daily with antibiotic alone, antibiotic with tea tree oil, and antibiotic with terpinen-4-ol for 6 days. Median MICs for each antibiotic alone increased 4- to 16-fold by day 6. Subinhibitory tea tree oil or te...

Eleven essential oils (EOs) were evaluated for their antibacterial properties, against Vancomycin-Resistant Enterococci (VRE) and E. coli O157:H7. EOs were introduced into Brain Heart Infusion agar (BHI) (15ml) at a concentration of 0.25 to 2% (vol/vol) to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for each pathogen evaluated. Results showed that the most active essential oils against bacteria tested were thyme oil, with MIC90 and MBC90 for the VRA strains of 0.25% and 0.5%, respectively. Eucalyptus, juniper and clove oils were the least potent agent, with MIC90 and MBC90 of 2%. Furthermore, the inhibitory effect of these EO were evaluated against VRE and E. coli O157:H7, experimentally inoculated (103 cfu/g) in Feta soft cheese and minced beef meat, which was mixed with different concentrations (0.1%, 0.5% and 1%) of the EO and stored at 7 ºC for 14 days. Out of eucalyptus, juniper, mint, rosemary, sage, clove and thyme oils tested against target bacteria sage and thyme showed the best results. Clove and mint did not show any effect on VRE and E. coli O157:H7 in both kinds of studied foods. The addition of thyme oil at concentrations of 0.5 and 1% caused best significant reduction in the growth rate of VRE and E. coli O157:H7 in cheese and meat at 7 ºC. It is concluded that selected plant EOs can act as potent inhibitors of both microorganisms in a food product. The results revealed the potential of thyme oil as a natural preservative in feta soft cheese and minced beef meat against VRE and E. coli O157:H7 contamination.

The biological activity of essential oils and their major components is well documented. Essential oils such as oregano and cinnamon are known for their effect against bacteria, fungi, and even viruses. The mechanism of action is proposed to be related to membrane and external cell structures, including cell walls. This study aimed to evaluate the biological activity of seven essential oils and eight of their major components against Gram-negative and Gram-positive bacteria, filamentous fungi, and protozoans. The antimicrobial activity was evaluated by determination of the Minimal Inhibitory Concentration for Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella Typhimurium, Shigella sonnei, Aspergillus niger, Aspergillus ochraceus, Alternaria alternata, and Fusarium oxysporium, the half-maximal inhibitory concentration (IC50) for Trypanosoma cruzi and Leishmania mexicana, and the median lethal dose (LD50) for Giardia lamblia. Results showed that oregano essential oil showed the best antibacterial activity (66-100 µg/mL), while cinnamon essential oil had the best fungicidal activity (66-116 µg/mL), and both showed excellent antiprotozoal activity (22-108 µg/mL). Regarding the major components, thymol and carvacrol were also good antimicrobials (23-200 µg/mL), and cinnamaldehyde was an antifungal compound (41-75 µg/mL). The major components were grouped according to their chemical structure as phenylpropanoids, terpenoids, and terpinenes. The statistical analysis of the grouped data demonstrated that protozoans were more susceptible to the essential oils, followed by fungi, Grampositive bacteria, and Gram-negative bacteria. The analysis for the major components showed that the most resistant microbial group was fungi, which was followed by bacteria, and protozoans were also more susceptible. Principal Component Analysis for the essential oils demonstrated the relationship between the biological activity and the microbial group tested, with the first three components explaining 94.3% of the data variability. The chemical structure of the major components was also related to the biological activity presented against the microbial groups tested, where the three first principal components accounted for 91.9% of the variability. The external structures and the characteristics of the cell membranes in the different microbial groups are determinant for their susceptibility to essential oils and their major components.

Hotrienol (3, 7-dimethyl-1, 5, 7-octatrien-3-ol, II) is the principal aroma component detected by headspace analysis in leatherwood (Eucryphia lucida) honey. It arises from the dehydration of 2, 6-dimethyl-3, 7-octadiene-2, 6-diol (I), the principal terpene in methylated and unmethylated ether extracts of leatherwood honey. The diol I was detected in leatherwood plant extracts. Methylated ether extracts of the honey also contained methyl 2-hydroxy-2-(4-methoxyphenyl) acetate (III), which has not been previously reported in honey, in addition to many other aromatic substances. Compound III was a major component of the acidic fraction of the plant extract. A methylated extract of unripe leatherwood honey collected after 1 week in the hive was found to contain methyl 2-hydroxy-3-phenylpropionate (IV) and an unidentified compound [m/z 91 (100), 180] as the principal components. The unidentified compound found in immature honey was not detected in the plant extracts.

Recent achievements have been made in the metabolic engineering of plant secondary metabolism. Various pathways have been altered using genes encoding biosynthetic enzymes or genes encoding regulatory proteins. In addition, antisense genes have been used to block competitive pathways, thereby increasing the flux towards the desired secondary metabolites.

This essay is  a comprehensive review on recent studies that related directly with cannabis essential oils. Five journal articles with various of application fields, different locations, in-dept analysis of cannabis chemical compounds, and comparison between hemp and marijuana are compared, and critically analyzed. Each individual journal article was summarized and evaluated to identify strength, weakness, and opportunity for further study. The results show that the trend of cannabis research is not only targeted to medical or few compounds like CBD or THC anymore, but rather than broader range of applications and more focused on terpenes and terpenoids that give different effects to multiple applications. This results study will lead new researchers to the current trend and perhaps, breakthrough of new utilization of cannabis plants.

For several decades, there has been interest in using the skin as a port of entry into the body for the systemic delivery of therapeutic agents. However, the upper layer of the skin, the stratum corneum, poses a barrier to the entry of many therapeutic entities. Given a compound, passive delivery rate is often dependent on two major physicochemical properties: the partition coefficient and solubility. The use of chemical enhancers and modifications of the thermodynamic activity of the applied drug are two frequently employed strategies to improve transdermal permeation. Chemical enhancers are known to enhance drug permeation by several mechanisms which include disrupting the organized intercellular lipid structure of the stratum corneum [1], ‘fluidizing’ the stratum corneum lipids [2], altering cellular proteins, and in some cases, extracting intercellular lipids [3]. However, the resulting increase in drug permeation using these techniques is rather modest especially for hydrophilic drugs. A number of other physical approaches such as iontophoresis, sonophoresis, ultrasound and the use of microneedles are now being studied to improve permeation of hydrophilic as well as lipophilic drugs. This article presents an overview of the use of iontophoresis alone and in conjunction with other approaches such as chemical enhancement, electroporation, sonophoresis, and use of microneedles and ion-exchange materials.