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Molecules, Volume 16, Issue 9 (September 2011), Pages 7183-8142

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Open AccessArticle Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media
Molecules 2011, 16(9), 8130-8142; https://doi.org/10.3390/molecules16098130
Received: 28 June 2011 / Revised: 26 August 2011 / Accepted: 26 August 2011 / Published: 22 September 2011
Cited by 23 | PDF Full-text (515 KB)
Abstract
The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in
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The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log Kf of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (Dc and Dc) for formation of (p-isopropyl-calix[6]arene·Cs)+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs)+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents. Full article
Open AccessArticle Antiphytoviral Activity of Sesquiterpene-Rich Essential Oils from Four Croatian Teucrium Species
Molecules 2011, 16(9), 8119-8129; https://doi.org/10.3390/molecules16098119
Received: 25 July 2011 / Revised: 12 September 2011 / Accepted: 14 September 2011 / Published: 21 September 2011
Cited by 17 | PDF Full-text (392 KB)
Abstract
The purpose of this study was to compare the essential oil profiles of four Croatian Teucrium species (Lamiaceae), as determined by GC and GC/MS, with their antiphytoviral efficiency. A phytochemical analysis showed that T. polium, T. flavum, T. montanum and T.
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The purpose of this study was to compare the essential oil profiles of four Croatian Teucrium species (Lamiaceae), as determined by GC and GC/MS, with their antiphytoviral efficiency. A phytochemical analysis showed that T. polium, T. flavum, T. montanum and T. chamaedrys are characterized by similar essential oil compositions. The investigated oils are characterized by a high proportion of the sesquiterpene hydrocarbons β-caryophyllene (7.1–52.0%) and germacrene D (8.7–17.0%). Other important components were β-pinene from T. montanum and α-pinene from T. flavum. The investigated essential oils were proved to reduce lesion number in the local host Chenopodium quinoa Willd. infected with Cucumber Mosaic Virus (CMV), with reductions of 41.4%, 22.9%, 44.3% and 25.7%, respectively. Full article
(This article belongs to the Special Issue Terpenoids)
Open AccessArticle Solid-Phase Synthesis of a New Diphosphate 5-Aminoimidazole-4-carboxamide Riboside (AICAR) Derivative and Studies toward Cyclic AICAR Diphosphate Ribose
Molecules 2011, 16(9), 8110-8118; https://doi.org/10.3390/molecules16098110
Received: 1 August 2011 / Revised: 9 September 2011 / Accepted: 13 September 2011 / Published: 21 September 2011
Cited by 13 | PDF Full-text (444 KB)
Abstract
The solid-phase synthesis of the first example of a new diphosphate AICAR derivative is reported. The new substance is characterized by the presence of a 5'-phosphate group while a second phosphate moiety is installed on a 5-hydroxypentyl chain attached to the 4-N
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The solid-phase synthesis of the first example of a new diphosphate AICAR derivative is reported. The new substance is characterized by the presence of a 5'-phosphate group while a second phosphate moiety is installed on a 5-hydroxypentyl chain attached to the 4-N-position of AICAR. Cyclization of the diphosphate derivative by pyrophosphate bond formation allowed for the formation of a novel AICAR-based cyclic ADP-ribose (cADPR) mimic. Full article
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Open AccessArticle Enzymatic Kinetic Resolution of tert-Butyl 2-(1-Hydroxyethyl)phenylcarbamate, A Key Intermediate to Chiral Organoselenanes and Organotelluranes
Molecules 2011, 16(9), 8098-8109; https://doi.org/10.3390/molecules16098098
Received: 19 August 2011 / Revised: 14 September 2011 / Accepted: 15 September 2011 / Published: 20 September 2011
Cited by 2 | PDF Full-text (552 KB)
Abstract
The enzymatic kinetic resolution of tert-butyl 2-(1-hydroxyethyl) phenylcarbamate via lipase-catalyzed transesterification reaction was studied. We investigated several reaction conditions and the carbamate was resolved by Candida antarctica lipase B (CAL-B), leading to the optically pure (R)- and (S)-enantiomers.
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The enzymatic kinetic resolution of tert-butyl 2-(1-hydroxyethyl) phenylcarbamate via lipase-catalyzed transesterification reaction was studied. We investigated several reaction conditions and the carbamate was resolved by Candida antarctica lipase B (CAL-B), leading to the optically pure (R)- and (S)-enantiomers. The enzymatic process showed excellent enantioselectivity (E > 200). (R)- and (S)-tert-butyl 2-(1-hydroxyethyl)phenylcarbamate were easily transformed into the corresponding (R)- and (S)-1-(2-aminophenyl)ethanols. Full article
(This article belongs to the Special Issue Enzyme-Catalyzed Reactions)
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Open AccessArticle Design and Synthesis of New N-(5-Trifluoromethyl)-1H-1,2,4-triazol-3-yl Benzenesulfonamides as Possible Antimalarial Prototypes
Molecules 2011, 16(9), 8083-8097; https://doi.org/10.3390/molecules16098083
Received: 1 August 2011 / Revised: 9 September 2011 / Accepted: 16 September 2011 / Published: 20 September 2011
Cited by 18 | PDF Full-text (706 KB)
Abstract
A rational approach was used to synthesize a new set of 15 1H-1,2,4-triazol-3-yl benzenesulfonamide derivatives with the aim of developing new antimalarial lead compounds. These derivatives were prepared in yields between 50% and 62%, and their structures were elucidated using IR,
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A rational approach was used to synthesize a new set of 15 1H-1,2,4-triazol-3-yl benzenesulfonamide derivatives with the aim of developing new antimalarial lead compounds. These derivatives were prepared in yields between 50% and 62%, and their structures were elucidated using IR, 1H-, 13C-, 19F-NMR, MS and elemental analysis. A docking study based on sulfonamides previously used against malaria identified trifluoromethyl-substituted derivatives to be the best lead compounds for new antimalarial drug development. Full article
(This article belongs to the Special Issue Fluorine Chemistry 2016)
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Open AccessCommunication Two New Triterpenoids from Lysimachia heterogenea Klatt and Evaluation of Their Cytotoxicity
Molecules 2011, 16(9), 8076-8082; https://doi.org/10.3390/molecules16098076
Received: 15 August 2011 / Revised: 7 September 2011 / Accepted: 8 September 2011 / Published: 20 September 2011
Cited by 8 | PDF Full-text (372 KB)
Abstract
Two new 13,28-epoxy oleanane-type triterpenoids, namely heterogenoside E and F, were isolated from Lysimachia heterogenea Klatt, together with the eight known compounds: palmitic acid, β-stigmasterol, kaempferol, quercetin, hyperin, isorhamnetin, isorhamnetin-3-O-galactopyranoside and anagallisin C. Heterogenoside F possesses acetoxyl groups at the
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Two new 13,28-epoxy oleanane-type triterpenoids, namely heterogenoside E and F, were isolated from Lysimachia heterogenea Klatt, together with the eight known compounds: palmitic acid, β-stigmasterol, kaempferol, quercetin, hyperin, isorhamnetin, isorhamnetin-3-O-galactopyranoside and anagallisin C. Heterogenoside F possesses acetoxyl groups at the unusual C-21 and C-22 positions of its oleanane skeleton. The cytotoxic activities of anagallisin C, heterogenoside E and F were weak. Full article
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Open AccessArticle Effects of St John's Wort (Hypericum perforatum L.) Extracts on Epileptogenesis
Molecules 2011, 16(9), 8062-8075; https://doi.org/10.3390/molecules16098062
Received: 22 August 2011 / Revised: 13 September 2011 / Accepted: 15 September 2011 / Published: 19 September 2011
Cited by 7 | PDF Full-text (439 KB) | Supplementary Files
Abstract
The purpose of this study was to investigate the effects of treatment with water, n-butanol and ether extracts of Hypercom perforatum L. on epileptogenesis in rabbits. Animals from the control group received solvent-ethanol, and the kindling model of epilepsy was used.
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The purpose of this study was to investigate the effects of treatment with water, n-butanol and ether extracts of Hypercom perforatum L. on epileptogenesis in rabbits. Animals from the control group received solvent-ethanol, and the kindling model of epilepsy was used. Epileptic focus was induced in Chinchilla rabbits by stimulation of the hippocampus. The following parameters were determined: the minimum current strength necessary to induce after-discharge (AD) – discharges appearing after cessation of stimulation; AD duration; the number of stimulations necessary to induce spontaneous kindling; and the latency time for the development of full kindling. The results obtained indicate that epileptogenesis is influenced by Hypericum perforatum L. extract treatment. Animals treated with an ether extract of Hypericum perforatum L. required significantly weaker minimum current strengths for the development of epileptogenic focus, and displayed longer AD times, while the number of electro-stimulations necessary for full kindling was less. In contrast, animals treated with water and n-butanol extracts required increased electro-stimulations for the development of epileptic discharge, and displayed shortened AD durations versus controls. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessArticle A Short Synthesis of Bisabolane Sesquiterpenes
Molecules 2011, 16(9), 8053-8061; https://doi.org/10.3390/molecules16098053
Received: 31 August 2011 / Revised: 4 September 2011 / Accepted: 14 September 2011 / Published: 19 September 2011
Cited by 7 | PDF Full-text (436 KB)
Abstract
A facile total synthesis of three members of the bisabolane sesquiterpene family, namely (±)-curcumene, (±)-xanthorrhizol and (±)-curcuhydroquinone had been achieved in high overall yield. The synthesis used bromobenzene derivatives as starting materials. The halogen-lithium exchange followed by addition of isoprenylacetone and reduction of
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A facile total synthesis of three members of the bisabolane sesquiterpene family, namely (±)-curcumene, (±)-xanthorrhizol and (±)-curcuhydroquinone had been achieved in high overall yield. The synthesis used bromobenzene derivatives as starting materials. The halogen-lithium exchange followed by addition of isoprenylacetone and reduction of the obtained carbinols are the key steps of the synthetic pathway. This synthetic approach provides a new route to the bisabolane sesquiterpenes. Full article
(This article belongs to the Special Issue Terpenoids)
Open AccessCommunication Intramolecular C-H···O Hydrogen Bonding in 1,4-Dihydropyridine Derivatives
Molecules 2011, 16(9), 8041-8052; https://doi.org/10.3390/molecules16098041
Received: 26 July 2011 / Revised: 8 September 2011 / Accepted: 9 September 2011 / Published: 19 September 2011
Cited by 15 | PDF Full-text (562 KB) | Supplementary Files
Abstract
The diastereotopy of the methylene protons at positions 2 and 6 in 1,4-dihydropiridine derivatives with various substituents has been investigated. NMR spectroscopy and quantum chemistry calculations show that the CH···O intramolecular hydrogen bond is one of the factors amplifying the chemical shift differences
[...] Read more.
The diastereotopy of the methylene protons at positions 2 and 6 in 1,4-dihydropiridine derivatives with various substituents has been investigated. NMR spectroscopy and quantum chemistry calculations show that the CH···O intramolecular hydrogen bond is one of the factors amplifying the chemical shift differences in the 1H-NMR spectra. Full article
Open AccessCommunication Synthesis and NMR-Study of the 2,3,4,5-Tetraethylsilole Dianion [SiC4Et4]2−•2[Li]+
Molecules 2011, 16(9), 8033-8040; https://doi.org/10.3390/molecules16098033
Received: 31 August 2011 / Revised: 8 September 2011 / Accepted: 14 September 2011 / Published: 16 September 2011
Cited by 4 | PDF Full-text (419 KB)
Abstract
The previously unknown silole dianion [SiC4Et4]2−•2[Li]+ (3) was prepared by the sonication of 1,1-dichloro-2,3,4,5-tetraethyl-1-silacyclopentadiene [Cl2SiC4Et4, 2] with more than four equivalent of lithium in THF. 1H-,
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The previously unknown silole dianion [SiC4Et4]2−•2[Li]+ (3) was prepared by the sonication of 1,1-dichloro-2,3,4,5-tetraethyl-1-silacyclopentadiene [Cl2SiC4Et4, 2] with more than four equivalent of lithium in THF. 1H-, 13C-, and 29Si-NMR data of 3 are compared with those of the reported silole dianion [SiC4Ph4]2−. Trapping of 3 with trimethylchlorosilane gave 1,1-bis(trimethylsilyl)-2,3,4,5-tetraethyl-1-silacyclopentadiene [(Me3Si)2SiC4Et4, 4] in high yield. The silole of 2 was synthesized in high yield in three steps by a modified procedure using Cp2ZrCl2 via Cp2ZrC4Et4 and 1,4-dibromo-1,2,3,4-tetraethyl-1,3-butadiene. Full article
(This article belongs to the Special Issue Organosilicon Chemistry)
Open AccessReview The Potential of Tetrandrine as a Protective Agent for Ischemic Stroke
Molecules 2011, 16(9), 8020-8032; https://doi.org/10.3390/molecules16098020
Received: 25 August 2011 / Revised: 15 September 2011 / Accepted: 15 September 2011 / Published: 16 September 2011
Cited by 14 | PDF Full-text (368 KB)
Abstract
Stroke is one of the leading causes of mortality, with a high incidence of severe morbidity in survivors. The treatment to minimize tissue injury after stroke is still unsatisfactory and it is mandatory to develop effective treatment strategies for stroke. The pathophysiology of
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Stroke is one of the leading causes of mortality, with a high incidence of severe morbidity in survivors. The treatment to minimize tissue injury after stroke is still unsatisfactory and it is mandatory to develop effective treatment strategies for stroke. The pathophysiology of ischemic stroke is complex and involves many processes including energy failure, loss of ion homeostasis, increased intracellular calcium level, platelet aggregation, production of reactive oxygen species, disruption of blood brain barrier, and inflammation and leukocyte infiltration, etc. Tetrandrine, a bisbenzylisoquinoline alkaloid, has many pharmacologic effects including anti-inflammatory and cytoprotective effects. In addition, tetrandrine has been found to protect the liver, heart, small bowel and brain from ischemia/reperfusion injury. It is a calcium channel blocker, and can inhibit lipid peroxidation, reduce generation of reactive oxygen species, suppress the production of cytokines and inflammatory mediators, inhibit neutrophil recruitment and platelet aggregation, which are all devastating factors during ischemia/reperfusion injury of the brain. Because tetrandrine can counteract these important pathophysiological processes of ischemic stroke, it has the potential to be a protective agent for ischemic stroke. Full article
(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)
Open AccessReview Exploiting the Nucleotide Substrate Specificity of Repair DNA Polymerases To Develop Novel Anticancer Agents
Molecules 2011, 16(9), 7994-8019; https://doi.org/10.3390/molecules16097994
Received: 5 July 2011 / Revised: 26 August 2011 / Accepted: 13 September 2011 / Published: 16 September 2011
Cited by 8 | PDF Full-text (522 KB)
Abstract
The genome is constantly exposed to mutations that can originate during replication or as a result of the action of both endogenous and/or exogenous damaging agents [such as reactive oxygen species (ROS), UV light, genotoxic environmental compounds, etc.]. Cells have developed a
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The genome is constantly exposed to mutations that can originate during replication or as a result of the action of both endogenous and/or exogenous damaging agents [such as reactive oxygen species (ROS), UV light, genotoxic environmental compounds, etc.]. Cells have developed a set of specialized mechanisms to counteract this mutational burden. Many cancer cells have defects in one or more DNA repair pathways, hence they rely on a narrower set of specialized DNA repair mechanisms than normal cells. Inhibiting one of these pathways in the context of an already DNA repair-deficient genetic background, will be more toxic to cancer cells than to normal cells, a concept recently exploited in cancer chemotherapy by the synthetic lethality approach. Essential to all DNA repair pathways are the DNA pols. Thus, these enzymes are being regarded as attractive targets for the development of specific inhibitors of DNA repair in cancer cells. In this review we examine the current state-of-the-art in the development of nucleotide analogs as inhibitors of repair DNA polymerases. Full article
(This article belongs to the Special Issue Nucleoside Analogues)
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Open AccessReview Thymidine Analogues for Tracking DNA Synthesis
Molecules 2011, 16(9), 7980-7993; https://doi.org/10.3390/molecules16097980
Received: 31 August 2011 / Accepted: 8 September 2011 / Published: 15 September 2011
Cited by 62 | PDF Full-text (679 KB)
Abstract
Replicating cells undergo DNA synthesis in the highly regulated, S-phase of the cell cycle. Analogues of the pyrimidine deoxynucleoside thymidine may be inserted into replicating DNA, effectively tagging dividing cells allowing their characterisation. Tritiated thymidine, targeted using autoradiography was technically demanding and superseded
[...] Read more.
Replicating cells undergo DNA synthesis in the highly regulated, S-phase of the cell cycle. Analogues of the pyrimidine deoxynucleoside thymidine may be inserted into replicating DNA, effectively tagging dividing cells allowing their characterisation. Tritiated thymidine, targeted using autoradiography was technically demanding and superseded by 5-bromo-2-deoxyuridine (BrdU) and related halogenated analogues, detected using antibodies. Their detection required the denaturation of DNA, often constraining the outcome of investigations. Despite these limitations BrdU alone has been used to target newly synthesised DNA in over 20,000 reviewed biomedical studies. A recent breakthrough in “tagging DNA synthesis” is the thymidine analogue 5-ethynyl-2′-deoxyuridine (EdU). The alkyne group in EdU is readily detected using a fluorescent azide probe and copper catalysis using ‘Huisgen’s reaction’ (1,3-dipolar cycloaddition or ‘click chemistry’). This rapid, two-step biolabelling approach allows the tagging and imaging of DNA within cells whilst preserving the structural and molecular integrity of the cells. The bio-orthogonal detection of EdU allows its application in more experimental assays than previously possible with other “unnatural bases”. These include physiological, anatomical and molecular biological experimentation in multiple fields including, stem cell research, cancer biology, and parasitology. The full potential of EdU and related molecules in biomedical research remains to be explored. Full article
(This article belongs to the Special Issue Nucleoside Analogues)
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Open AccessReview Modulation of Animal and Human Hematopoiesis by β-Glucans: A Review
Molecules 2011, 16(9), 7969-7979; https://doi.org/10.3390/molecules16097969
Received: 15 August 2011 / Revised: 5 September 2011 / Accepted: 9 September 2011 / Published: 15 September 2011
Cited by 16 | PDF Full-text (377 KB)
Abstract
β-Glucans are cell wall constituents of bacteria, yeast, fungi, and plants. They are not expressed in mammalian cells, but they are recognized by mammalian cells as pathogen-associated molecular patterns by pattern recognition receptors and thus act as biological response modifiers. This review summarizes
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β-Glucans are cell wall constituents of bacteria, yeast, fungi, and plants. They are not expressed in mammalian cells, but they are recognized by mammalian cells as pathogen-associated molecular patterns by pattern recognition receptors and thus act as biological response modifiers. This review summarizes data on the hematopoiesis-stimulating effects of β-glucans, as well as on their ability to enhance bone marrow recovery after an injury. β-Glucans have been shown to support murine hematopoiesis suppressed by ionizing radiation or cytotoxic anti-cancer therapy. They also enhance stem cell homing and engraftment. Basically, two forms of β-glucan preparations have been investigated, namely particulate and soluble ones. β-Glucans are generally well tolerated, the particulate forms showing a higher incidence of undesirable side effects. Taken together, the hematopoiesis-stimulating properties of β-glucans predetermine these biological response modifiers to ever increasing use in human medicinal practice. Full article
(This article belongs to the Special Issue Natural Polysaccharides: Chemistry, Bioactivity and Analysis)
Open AccessArticle Allicin Reduces the Production of α-Toxin by Staphylococcus aureus
Molecules 2011, 16(9), 7958-7968; https://doi.org/10.3390/molecules16097958
Received: 20 July 2011 / Revised: 1 September 2011 / Accepted: 7 September 2011 / Published: 15 September 2011
Cited by 18 | PDF Full-text (482 KB)
Abstract
Staphylococcus aureus causes a broad range of life-threatening diseases in humans. The pathogenicity of this micro-organism is largely dependent upon its virulence factors. One of the most extensively studied virulence factors is the extracellular protein α-toxin. In this study, we show that allicin,
[...] Read more.
Staphylococcus aureus causes a broad range of life-threatening diseases in humans. The pathogenicity of this micro-organism is largely dependent upon its virulence factors. One of the most extensively studied virulence factors is the extracellular protein α-toxin. In this study, we show that allicin, an organosulfur compound, was active against S. aureus with MICs ranged from 32 to 64 μg/mL. Haemolysis, Western blot and real-time RT-PCR assays were used to evaluate the effects of allicin on S. aureus α-toxin production and on the levels of gene expression, respectively. The results of our study indicated that sub-inhibitory concentrations of allicin decreased the production of α-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in a dose-dependent manner. Furthermore, the transcriptional levels of agr (accessory gene regulator) in S. aureus were inhibited by allicin. Therefore, allicin may be useful in the treatment of α-toxin-producing S. aureus infections. Full article
Open AccessArticle Isolation and Purification of Oridonin from the Whole Plant of Isodon rubescens by High-Speed Counter-Current Chromatography
Molecules 2011, 16(9), 7949-7957; https://doi.org/10.3390/molecules16097949
Received: 18 July 2011 / Revised: 24 August 2011 / Accepted: 25 August 2011 / Published: 14 September 2011
Cited by 7 | PDF Full-text (645 KB)
Abstract
Semi-preparative high-speed counter-current chromatography (HSCCC) was successfully used for isolation and purification of oridonin from Isodon rubescens by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (2.8:5:2.8:5, v/v/v/v). The targeted compound isolated, collected and purified by HSCCC was analyzed by high performance
[...] Read more.
Semi-preparative high-speed counter-current chromatography (HSCCC) was successfully used for isolation and purification of oridonin from Isodon rubescens by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (2.8:5:2.8:5, v/v/v/v). The targeted compound isolated, collected and purified by HSCCC was analyzed by high performance liquid chromatography (HPLC). A total of 40.6 mg of oridonin with the purity of 73.5% was obtained in less than 100 min from 100 mg of crude Isodon rubescens extract. The chemical structure of the compound was identified by IR, 1H-NMR and 13C-NMR. Full article
(This article belongs to the Section Natural Products Chemistry)
Open AccessArticle Chemical Profile of the Organic Residue from Ancient Amphora Found in the Adriatic Sea Determined by Direct GC and GC-MS Analysis
Molecules 2011, 16(9), 7936-7948; https://doi.org/10.3390/molecules16097936
Received: 18 August 2011 / Revised: 7 September 2011 / Accepted: 7 September 2011 / Published: 14 September 2011
Cited by 9 | PDF Full-text (577 KB)
Abstract
An ancient organic residue was collected from the bottom of a Greco-Italian amphora found in the Adriatic Sea and investigated by direct GC and GC-MS analysis. The headspace composition was determined by HS-SPME using: (1) DVB/CAR/PDMS and (2) PDMS/DVB fibres. Higher percentages of
[...] Read more.
An ancient organic residue was collected from the bottom of a Greco-Italian amphora found in the Adriatic Sea and investigated by direct GC and GC-MS analysis. The headspace composition was determined by HS-SPME using: (1) DVB/CAR/PDMS and (2) PDMS/DVB fibres. Higher percentages of benzene derivatives, monoterpenes and other low-molecular aliphatic compounds were obtained by method (1) in contrast to higher percentage of naphthalene and phenanthrene derivatives found by method (2). In comparison with the composition of pine resin, it is more likely that the found low-molecular aliphatic alcohols, acids, esters and carbonyls with 2-phenylethanol were trapped and preserved within the organic residue from stored wine – the amphora’s originally content. Semi-volatile diterpenes methyl dehydroabietate (33.6%) and retene (24.1%) were dominant in the residue CH2Cl2 solution. Other abundant compounds were 1,4-dimethoxyphenanthrene (6.8%) as well as other naphthalene and/or phenanthrene derivatives [7-(1-methylethyl)-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydronaphthalene, 7-(1-methylethyl)-1,4a-dimethyl-2,3,4,4a,9,10-hexahydrophenanthrene, 7-(1-methylethyl)-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydro-phenanthrene, 3,6-dimethylphenanthrene and 2,3,5-trimethylphenanthrene]. Possible sources and formation pathways of the major compounds in the residue were discussed. Full article
Open AccessReview Pyrene: A Probe to Study Protein Conformation and Conformational Changes
Molecules 2011, 16(9), 7909-7935; https://doi.org/10.3390/molecules16097909
Received: 1 August 2011 / Revised: 4 September 2011 / Accepted: 6 September 2011 / Published: 14 September 2011
Cited by 113 | PDF Full-text (2960 KB)
Abstract
The review focuses on the unique spectral features of pyrene that can be utilized to investigate protein structure and conformation. Pyrene is a fluorescent probe that can be attached covalently to protein side chains, such as sulfhydryl groups. The spectral features of pyrene
[...] Read more.
The review focuses on the unique spectral features of pyrene that can be utilized to investigate protein structure and conformation. Pyrene is a fluorescent probe that can be attached covalently to protein side chains, such as sulfhydryl groups. The spectral features of pyrene are exquisitely sensitive to the microenvironment of the probe: it exhibits an ensemble of monomer fluorescence emission peaks that report on the polarity of the probe microenvironment, and an additional band at longer wavelengths, the appearance of which reflects the presence of another pyrene molecule in spatial proximity (~10 Å). Its high extinction coefficient allows us to study labeled proteins in solution at physiologically relevant concentrations. The environmentally- and spatially-sensitive features of pyrene allow monitoring protein conformation, conformational changes, protein folding and unfolding, protein-protein, protein-lipid and protein-membrane interactions. Full article
Open AccessArticle Studies on Log Po/w of Quinoxaline di-N-Oxides: A Comparison of RP-HPLC Experimental and Predictive Approaches
Molecules 2011, 16(9), 7893-7908; https://doi.org/10.3390/molecules16097893
Received: 30 August 2011 / Revised: 6 September 2011 / Accepted: 7 September 2011 / Published: 13 September 2011
Cited by 4 | PDF Full-text (414 KB) | Supplementary Files
Abstract
As reported in our previous papers, a series of quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives were synthesized and studied as anti-tuberculosis agents. Here, the capability of the shake-flask method was studied and the retention time (expressed as log K) of 20 compounds were
[...] Read more.
As reported in our previous papers, a series of quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives were synthesized and studied as anti-tuberculosis agents. Here, the capability of the shake-flask method was studied and the retention time (expressed as log K) of 20 compounds were determined by RP-HPLC analysis. We found that the prediction of log P by the RP-HPLC analysis can result in a high accuracy and can replace the shake-flask method avoiding the experimental problems presented by quinoxaline di-N-oxides. The studied compounds were subjected to the ALOGPS module with the aim of comparing experimental log Po/w values and predicted data. Moreover, a preliminary in silico screening of the QSAR relationship was made confirming the influence of reduction peak potential, lipophilicity, H-bond donor capacity and molecular dimension descriptors on anti-tuberculosis activity. Full article
Open AccessArticle Formulation and Evaluation of Celastrol-Loaded Liposomes
Molecules 2011, 16(9), 7880-7892; https://doi.org/10.3390/molecules16097880
Received: 21 July 2011 / Revised: 5 September 2011 / Accepted: 5 September 2011 / Published: 13 September 2011
Cited by 27 | PDF Full-text (586 KB)
Abstract
The main purpose of this study was to evaluate the intestinal absorption and the antineoplastic effect of the poorly water-soluble drug celastrol when liposomes were used as oral drug delivery system. Liposomes were prepared by the ethanol-injection method. An optimized liposome formulation composed
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The main purpose of this study was to evaluate the intestinal absorption and the antineoplastic effect of the poorly water-soluble drug celastrol when liposomes were used as oral drug delivery system. Liposomes were prepared by the ethanol-injection method. An optimized liposome formulation composed of phospholipid, cholesterol and Tween-80 resulted in favorable encapsulation efficiency at 98.06 ± 0.94%. Homogeneous and stable particle size of 89.6 ± 7.3 nm and zeta potential of −(87.7 ± 5.8) mV were determined by laser particle size analyzer. Subsequently, the four-site perfusion rat intestinal model revealed that celastrol-loaded liposomes had improved effective permeability compared to the free drug in four intestinal segments (p < 0.05). Moreover, celastrol-loaded liposomes could also inhibit the tumor growth in C57BL/6 mice. These results suggest that liposomes could be a promising perioral carrier for celastrol. Full article
Open AccessArticle Schiff Bases of Indoline-2,3-dione: Potential Novel Inhibitors of Mycobacterium Tuberculosis (Mtb) DNA Gyrase
Molecules 2011, 16(9), 7864-7879; https://doi.org/10.3390/molecules16097864
Received: 27 July 2011 / Revised: 23 August 2011 / Accepted: 7 September 2011 / Published: 13 September 2011
Cited by 28 | PDF Full-text (778 KB)
Abstract
In the present study a series of Schiff bases of indoline-2,3-dione were synthesized and investigated for their Mtb gyrase inhibitory activity. Promising inhibitory activity was demonstrated with some of these derivatives, which exhibited IC50 values ranging from 50–157 mM. The orientation and
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In the present study a series of Schiff bases of indoline-2,3-dione were synthesized and investigated for their Mtb gyrase inhibitory activity. Promising inhibitory activity was demonstrated with some of these derivatives, which exhibited IC50 values ranging from 50–157 mM. The orientation and the ligand-receptor interactions of such molecules within the Mtb DNA gyrase A subunit active site were investigated applying a multi-step docking protocol using Molecular Operating Environment (MOE) and Autodock4 docking software. The results revealed the importance of the isatin moiety and the connecting side chain for strong interactions with the enzyme active site. Among the tested compounds the terminal aromatic ring benzofuran showed the best activity. Promising new leads for developing a novel class of Mtb gyrase inhibitors were obtained from Schiff bases of indoline-2,3-dione. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessReview One Step Formation of Propene from Ethene or Ethanol through Metathesis on Nickel Ion-loaded Silica
Molecules 2011, 16(9), 7844-7863; https://doi.org/10.3390/molecules16097844
Received: 30 June 2011 / Revised: 4 August 2011 / Accepted: 5 September 2011 / Published: 13 September 2011
Cited by 34 | PDF Full-text (1975 KB)
Abstract
Increased propene production is presently one of the most significant objectives in petroleum chemistry. Especially the one-step conversion of ethene to propene (ETP reaction, 3C2H4 ® 2C3H6) is the most desired process. In our efforts, nickel
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Increased propene production is presently one of the most significant objectives in petroleum chemistry. Especially the one-step conversion of ethene to propene (ETP reaction, 3C2H4 ® 2C3H6) is the most desired process. In our efforts, nickel ion-loaded mesoporous silica could turn a new type of ETP reaction into reality. The one-step conversion of ethene was 68% and the propene selectivity was 48% in a continuous gas-flow system at 673 K and atmospheric pressure. The reactivity of lower olefins and the dependences of the ETP reaction on the contact time and the partial pressure of ethene were consistent with a reaction mechanism involving dimerization of ethene to 1-butene, isomerization of 1-butene to 2-butene, and metathesis of 2-butene and ethene to yield propene. The reaction was then expanded to an ethanol-to-propene reaction on the same catalyst, in which two possible reaction routes are suggested to form ethene from ethanol. The catalysts were characterized mainly by EXAFS and TPR techniques. The local structures of the nickel species active for the ETP reaction were very similar to that of layered nickel silicate, while those on the inert catalysts were the same as that of NiO particles. Full article
(This article belongs to the Special Issue Olefin Metathesis and Its Application)
Open AccessReview Gold-Catalyzed Cyclizations of Alkynol-Based Compounds: Synthesis of Natural Products and Derivatives
Molecules 2011, 16(9), 7815-7843; https://doi.org/10.3390/molecules16097815
Received: 15 August 2011 / Revised: 5 September 2011 / Accepted: 8 September 2011 / Published: 13 September 2011
Cited by 41 | PDF Full-text (649 KB)
Abstract
The last decade has witnessed dramatic growth in the number of reactions catalyzed by gold complexes because of their powerful soft Lewis acid nature. In particular, the gold-catalyzed activation of propargylic compounds has progressively emerged in recent years. Some of these gold-catalyzed reactions
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The last decade has witnessed dramatic growth in the number of reactions catalyzed by gold complexes because of their powerful soft Lewis acid nature. In particular, the gold-catalyzed activation of propargylic compounds has progressively emerged in recent years. Some of these gold-catalyzed reactions in alkynes have been optimized and show significant utility in organic synthesis. Thus, apart from significant methodology work, in the meantime gold-catalyzed cyclizations in alkynol derivatives have become an efficient tool in total synthesis. However, there is a lack of specific review articles covering the joined importance of both gold salts and alkynol-based compounds for the synthesis of natural products and derivatives. The aim of this Review is to survey the chemistry of alkynol derivatives under gold-catalyzed cyclization conditions and its utility in total synthesis, concentrating on the advances that have been made in the last decade, and in particular in the last quinquennium. Full article
(This article belongs to the Special Issue Gold Catalysts)
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Open AccessArticle Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine, a Novel Camptothecin Analogue, Induces Apoptosis towards Hepatocellular Carcinoma SMMC-7721 Cells
Molecules 2011, 16(9), 7803-7814; https://doi.org/10.3390/molecules16097803
Received: 28 July 2011 / Revised: 25 August 2011 / Accepted: 6 September 2011 / Published: 13 September 2011
Cited by 8 | PDF Full-text (2229 KB)
Abstract
Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine (B2) is a novel camptothecin analogue. Our previous study had shown that it displayed higher cytoxicity activity towards hepatocellular carcinoma SMMC-7721 cells than camptothecin (CPT) in vitro. In this paper, the underlying mechanism of anti-proliferation of B2
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Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine (B2) is a novel camptothecin analogue. Our previous study had shown that it displayed higher cytoxicity activity towards hepatocellular carcinoma SMMC-7721 cells than camptothecin (CPT) in vitro. In this paper, the underlying mechanism of anti-proliferation of B2 towards SMMC-7721 cells was further examined. Cell growth inhibition of B2 was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; morphological changes were observed under Laser Scanning Confocal Microscope (LSCM); cell cycle distribution, apoptotic population, changes in mitochondrial membrane potential, intracellular calcium concentration and reactive oxygen species (ROS) production were determined by flow cytometry (FCM). Activities of caspase-3 and caspase-9 were measured, and the expression level of Bcl-2 and Bax proteins were analyzed by Western blot. The results suggested that B2 inhibited SMMC-7721 cell growth by causing cell cycle arrest at the S and G2/M phases, and induced apoptosis involving a mitochondrial pathway. B2 appears to cause a high induction of apoptosis on SMMC-7721 cells in vitro, which suggests it might be a potential drug for cancer therapy. Full article
Open AccessArticle Synthesis, Characterization and Fluorescent Property Evaluation of 1,3,5-Triaryl-2-pyrazolines
Molecules 2011, 16(9), 7789-7802; https://doi.org/10.3390/molecules16097789
Received: 12 July 2011 / Revised: 3 August 2011 / Accepted: 10 August 2011 / Published: 13 September 2011
Cited by 41 | PDF Full-text (666 KB)
Abstract
A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the
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A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the reaction mixture onto crushed ice. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The 1,3,5-triaryl-2-pyrazolines bearing homologous alkoxy groups were found to possess fluorescence properties in the blue region of the visible spectrum when irradiated with ultraviolet radiation. The fluorescent behavior of these compounds was studied by UV-Vis and emission spectroscopy, performed at room temperature. Full article
Open AccessArticle Chemical, Antioxidant and Antimicrobial Investigations of Pinus cembra L. Bark and Needles
Molecules 2011, 16(9), 7773-7788; https://doi.org/10.3390/molecules16097773
Received: 4 August 2011 / Revised: 4 September 2011 / Accepted: 8 September 2011 / Published: 13 September 2011
Cited by 33 | PDF Full-text (448 KB)
Abstract
The chemical constituents and biological activity of Pinus cembra L. (Pinaceae), native to the Central European Alps and the Carpathian Mountains, are not well known. The aim of the present work was to examine the phenolic content, antioxidant and antimicrobial effects of hydromethanolic
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The chemical constituents and biological activity of Pinus cembra L. (Pinaceae), native to the Central European Alps and the Carpathian Mountains, are not well known. The aim of the present work was to examine the phenolic content, antioxidant and antimicrobial effects of hydromethanolic extracts of Pinus cembra L. bark and needles. Bark extract had higher concentrations of total phenolics (299.3 vs. 78.22 mg gallic acid equivalents/g extract), flavonoids (125.3 vs. 19.84 mg catechin equivalents/g extract) and proanthocyanidins (74.3 vs. 12.7 mg cyanidin equivalents/g extract) than needle extract and was more active as a free radical scavenger, reducing agent and antimicrobial agent. The EC50 values in the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) and reducing power assays were 71.1, 6.3 and 26 mg/mL for bark extract and 186.1, 24 and 104 mg/mL for needle extract, respectively. In addition, needle extract showed ferrous ions chelating effects (EC50 = 1,755 μg/mL). The antimicrobial effects against Staphylococcus aureus, Sarcina lutea, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans were assessed by the agar diffusion method. Both extracts (4 mg/well) were active against all the microorganisms tested; bark extract showed higher inhibition on all strains. These results indicate that Pinus cembra L. bark and needles are good sources of phytochemicals with antioxidant and antimicrobial activities. Full article
(This article belongs to the Section Natural Products Chemistry)
Open AccessArticle Physicochemical Properties, in Vitro Antioxidant Activities and Inhibitory Potential against α-Glucosidase of Polysaccharides from Ampelopsis grossedentata Leaves and Stems
Molecules 2011, 16(9), 7762-7772; https://doi.org/10.3390/molecules16097762
Received: 1 July 2011 / Revised: 28 August 2011 / Accepted: 8 September 2011 / Published: 9 September 2011
Cited by 11 | PDF Full-text (266 KB)
Abstract
In the present study, polysaccharides named ALPS and ASPS were isolated from Ampelopsis grossedentata leaves and stems, respectively. Physicochemical properties, in vitro antioxidant activities and the inhibitory effects on α-glucosidase of ALPS and ASPS were investigated. It was found that both ALPS and
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In the present study, polysaccharides named ALPS and ASPS were isolated from Ampelopsis grossedentata leaves and stems, respectively. Physicochemical properties, in vitro antioxidant activities and the inhibitory effects on α-glucosidase of ALPS and ASPS were investigated. It was found that both ALPS and ASPS were acid protein-bound heteropolysaccharides, although with considerably different chemical composition and molecular weight distribution. Meanwhile, in comparison with ALPS, ASPS exhibited stronger antioxidant activity and inhibitory potential against α-glucosidase according to the in vitro evaluation. Moreover, our results suggested that protein and uronic acid might, at least partly, contribute positively to the biological behavior of ALPS and ASPS. Full article
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Open AccessArticle Stopped-Flow Spectrophotometric Study of the Kinetics and Mechanism of CO2 Uptake by cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ Cation and the Acid-Catalyzed Decomposition of cis-[Cr(C2O4)(BaraNH2)OCO2] Anion in Aqueous Solution
Molecules 2011, 16(9), 7746-7761; https://doi.org/10.3390/molecules16097746
Received: 1 August 2011 / Revised: 1 September 2011 / Accepted: 6 September 2011 / Published: 9 September 2011
Cited by 4 | PDF Full-text (535 KB)
Abstract
The kinetics of CO2 uptake by the cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ complex cation and the acid hydrolysis of the cis-[Cr(C2O4)(BaraNH2)OCO2] complex anion (where
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The kinetics of CO2 uptake by the cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ complex cation and the acid hydrolysis of the cis-[Cr(C2O4)(BaraNH2)OCO2] complex anion (where BaraNH2 denotes methyl 3-amino-2,3-dideoxy-b-D-arabino-hexopyranoside) were studied using the stopped-flow technique. The reactions under study were investigated in aqueous solution in the 288–308 K temperature range. In the case of the reaction between CO2 and cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ cation variable pH values (6.82–8.91) and the constant ionic strength of solution (H+, Na+, ClO4 = 1.0) were used. Carbon dioxide was generated by the reaction between sodium pyruvate and hydrogen peroxide. The acid hydrolysis of cis-[Cr(C2O4)(BaraNH2)OCO2] was investigated for varying concentrations of H+ ions (0.01–2.7 M). The obtained results enabled the determination of the number of steps of the studied reactions. Based on the kinetic equations, rate constants were determined for each step. Finally, mechanisms for both reactions were proposed and discussed. Based on the obtained results it was concluded that the carboxylation (CO2 uptake) reactions of cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ and the decarboxylation (acid hydrolysis) of the cis-[Cr(C2O4)(BaraNH2)OCO2] are the opposite of each other. Full article
(This article belongs to the Special Issue Flow Chemistry)
Open AccessArticle Synthesis and in Vitro Antimicrobial Activity of Some Pyrazolyl-1-carboxamide Derivatives
Molecules 2011, 16(9), 7736-7745; https://doi.org/10.3390/molecules16097736
Received: 13 August 2011 / Revised: 25 August 2011 / Accepted: 31 August 2011 / Published: 9 September 2011
Cited by 13 | PDF Full-text (430 KB)
Abstract
A series of 3,5-disubstituted pyrazole-1-carboxamides were obtained by treatment of chalcones with semicarbazide hydrochloride in dioxane containing sodium acetate/acetic acid as a buffer solution. N-acetyl derivatives of pyrazole-1-carboxamides were isolated in good yields either by treatment of the carboxamide derivatives with acetic anhydride
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A series of 3,5-disubstituted pyrazole-1-carboxamides were obtained by treatment of chalcones with semicarbazide hydrochloride in dioxane containing sodium acetate/acetic acid as a buffer solution. N-acetyl derivatives of pyrazole-1-carboxamides were isolated in good yields either by treatment of the carboxamide derivatives with acetic anhydride or refluxing chalcones with semicarbazide in ethanol containing few drops of acetic acid to give the corresponding hydrazones. Subsequent treatment of hydrazones with acetic anhydride gave the desired N-acetyl pyrazole-1-carboxamides derivatives. When chalcones were refluxed with dioxane containing few drops of acetic acid, 4,5-dihydropyrazole-1-carboxamides were isolated, which were subsequently oxidized using 5% sodium hypochlorite in dioxane to afford pyrazole-1-carboxamides. The structures of isolated compounds were confirmed by elemental analyses and spectral methods. The isolated compounds were tested for their antimicrobial activities. Full article
(This article belongs to the Special Issue Heterocycles)
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Open AccessArticle Chemical Composition and Possible in Vitro Phytotoxic Activity of Helichrsyum italicum (Roth) Don ssp. italicum
Molecules 2011, 16(9), 7725-7735; https://doi.org/10.3390/molecules16097725
Received: 25 July 2011 / Revised: 30 August 2011 / Accepted: 6 September 2011 / Published: 8 September 2011
Cited by 19 | PDF Full-text (317 KB)
Abstract
The chemical composition of the essential oil of Helichrysum italicum (Roth) Don ssp. italicum, collected in the National Park of Cilento and Diano Valley, Southern Italy, was studied by means of GC and GC/MS. Forty four compounds of 45 constituents were
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The chemical composition of the essential oil of Helichrysum italicum (Roth) Don ssp. italicum, collected in the National Park of Cilento and Diano Valley, Southern Italy, was studied by means of GC and GC/MS. Forty four compounds of 45 constituents were identified in the oil, mainly oxygenated sesquiterpenes. The essential oil was evaluated for its potential in vitro phytotoxic activity against germination and early radicle elongation of radish and garden cress. The radicle elongation of radish was significantly inhibited at the highest doses tested, while germination of both seeds was not affected. Full article
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