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Molecules, Volume 18, Issue 4 (April 2013), Pages 3641-4843

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Research

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Open AccessArticle Antibacterial Activity of Salicylanilide 4-(Trifluoromethyl)-benzoates
Molecules 2013, 18(4), 3674-3688; doi:10.3390/molecules18043674
Received: 1 February 2013 / Revised: 18 March 2013 / Accepted: 18 March 2013 / Published: 25 March 2013
Cited by 10 | PDF Full-text (281 KB) | HTML Full-text | XML Full-text
Abstract
The development of novel antimicrobial agents represents a timely research topic. Eighteen salicylanilide 4-(trifluoromethyl)benzoates were evaluated against Mycobacterium tuberculosis, M. avium and M. kansasii, eight bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) and for the inhibition of mycobacterial isocitrate lyase. Some
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The development of novel antimicrobial agents represents a timely research topic. Eighteen salicylanilide 4-(trifluoromethyl)benzoates were evaluated against Mycobacterium tuberculosis, M. avium and M. kansasii, eight bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) and for the inhibition of mycobacterial isocitrate lyase. Some compounds were further screened against drug-resistant M. tuberculosis and for their cytotoxicity. Minimum inhibitory concentrations (MICs) for all mycobacterial strains were within 0.5–32 μmol/L, with 4-chloro-2-[4-(trifluoromethyl)phenylcarbamoyl]phenyl 4-(trifluoromethyl)benzoate superiority. Gram-positive bacteria including MRSA were inhibited with MICs ³ 0.49 μmol/L, while Gram-negative ones were much less susceptible. Salicylanilide 4-(trifluoromethyl)benzoates showed significant antibacterial properties, for many strains being comparable to standard drugs (isoniazid, benzylpenicillin) with no cross-resistance. All esters showed mild inhibition of mycobacterial isocitrate lyase and four compounds were comparable to 3-nitropropionic acid without a direct correlation between in vitro MICs and enzyme inhibition. Full article
Open AccessArticle Synthesis of Esters of Ginsenoside Metabolite M1 and Their Cytotoxicity on MGC80-3 Cells
Molecules 2013, 18(4), 3689-3702; doi:10.3390/molecules18043689
Received: 20 December 2012 / Revised: 10 March 2013 / Accepted: 11 March 2013 / Published: 25 March 2013
Cited by 2 | PDF Full-text (393 KB) | HTML Full-text | XML Full-text
Abstract
Monoesters of ginsenoside metabolite M1 at the 3-OH, 4-OH and 6-OH positions of the glucose moiety at M1 were synthesized via the reaction of M1 with acyl chloride, or acid-N,N'-diisopropylcarbodiimide in the presence of DMAP. Their structures were fully characterized by
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Monoesters of ginsenoside metabolite M1 at the 3-OH, 4-OH and 6-OH positions of the glucose moiety at M1 were synthesized via the reaction of M1 with acyl chloride, or acid-N,N'-diisopropylcarbodiimide in the presence of DMAP. Their structures were fully characterized by spectral methods. The cytotoxicity of these compounds against then MGC80-3 human gastric cancer cell line was also assessed. High inhibitory effects were found at a concentration of 100 μg/mL. Full article
(This article belongs to the Section Organic Synthesis)
Open AccessArticle Probing Ionic Liquid Aqueous Solutions Using Temperature of Maximum Density Isotope Effects
Molecules 2013, 18(4), 3703-3711; doi:10.3390/molecules18043703
Received: 29 January 2013 / Revised: 6 March 2013 / Accepted: 15 March 2013 / Published: 25 March 2013
Cited by 2 | PDF Full-text (546 KB) | HTML Full-text | XML Full-text
Abstract
This work is a new development of an extensive research program that is investigating for the first time shifts in the temperature of maximum density (TMD) of aqueous solutions caused by ionic liquid solutes. In the present case we have compared the shifts
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This work is a new development of an extensive research program that is investigating for the first time shifts in the temperature of maximum density (TMD) of aqueous solutions caused by ionic liquid solutes. In the present case we have compared the shifts caused by three ionic liquid solutes with a common cation—1-ethyl-3-methylimidazolium coupled with acetate, ethylsulfate and tetracyanoborate anions—in normal and deuterated water solutions. The observed differences are discussed in terms of the nature of the corresponding anion-water interactions. Full article
(This article belongs to the Special Issue Isotope Effects)
Open AccessArticle Microwave Assisted Suzuki-Miyaura and Ullmann Type Homocoupling Reactions of 2- and 3-Halopyridines Using a Pd(OAc)2/Benzimidazolium Salt and Base Catalyst System
Molecules 2013, 18(4), 3712-3724; doi:10.3390/molecules18043712
Received: 1 March 2013 / Revised: 15 March 2013 / Accepted: 15 March 2013 / Published: 25 March 2013
Cited by 6 | PDF Full-text (256 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A number of novel benzimidazole derivatives 14 were synthesized and the catalytic activity of these compounds in a catalytic system consisting of a benzimidazolium salt/Pd(OAc)2/K2CO3 were investigated in the Suzuki-Miyaura and Ullmann type homocoupling reactions under
[...] Read more.
A number of novel benzimidazole derivatives 14 were synthesized and the catalytic activity of these compounds in a catalytic system consisting of a benzimidazolium salt/Pd(OAc)2/K2CO3 were investigated in the Suzuki-Miyaura and Ullmann type homocoupling reactions under microwave irradiation. We obtained both cross coupling and homocoupling products of pyridine and some side products such as dimethylaminopyridine and unsubstituted pyridine. Full article
(This article belongs to the Section Organic Synthesis)
Open AccessCommunication Anti-Inflammatory Cycloartane-Type Saponins of Astragalus membranaceus
Molecules 2013, 18(4), 3725-3732; doi:10.3390/molecules18043725
Received: 1 February 2013 / Revised: 19 March 2013 / Accepted: 20 March 2013 / Published: 25 March 2013
Cited by 14 | PDF Full-text (297 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A new cycloartane-type triterpene glycoside, agroastragaloside V (1) was isolated from the roots of Astragalus membranaceus. The structure was identified as 3-O-β-(2'-O-acetyl)-D-xylopyranosyl-6-O-β-D-glucopyranosyl-(24S)-3β,6α,24α,25-tetrahydroxy-
[...] Read more.
A new cycloartane-type triterpene glycoside, agroastragaloside V (1) was isolated from the roots of Astragalus membranaceus. The structure was identified as 3-O-β-(2'-O-acetyl)-D-xylopyranosyl-6-O-β-D-glucopyranosyl-(24S)-3β,6α,24α,25-tetrahydroxy- 9,19-cyclolanostane, by means of spectroscopic methods, including HR-FAB/MS, 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. Four known cycloartane glycosides, namely, agroastragaloside I (2), agroastragaloside II (3), isoastragaloside II (4) and astragaloside IV (5) were also isolated. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids)
Open AccessArticle Synthesis of Structured Lipids by Lipase-Catalyzed Interesterification of Triacetin with Camellia Oil Methyl Esters and Preliminary Evaluation of their Plasma Lipid-Lowering Effect in Mice
Molecules 2013, 18(4), 3733-3744; doi:10.3390/molecules18043733
Received: 17 December 2012 / Revised: 15 March 2013 / Accepted: 15 March 2013 / Published: 25 March 2013
Cited by 3 | PDF Full-text (249 KB) | HTML Full-text | XML Full-text
Abstract
Structured lipids (SLCTs triacylglycerols with short- and long-chain acyl residues) were synthesized by interesterification of triacetin and fatty acid methyl esters (FAMEs) from camellia oil, followed by molecular distillation for purification. Different commercial immobilized lipases (Lipozyme RM IM and Novozyme 435), the substrate
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Structured lipids (SLCTs triacylglycerols with short- and long-chain acyl residues) were synthesized by interesterification of triacetin and fatty acid methyl esters (FAMEs) from camellia oil, followed by molecular distillation for purification. Different commercial immobilized lipases (Lipozyme RM IM and Novozyme 435), the substrate molar ratios of FAMEs to triacetin, the reaction temperatures and the lipase amounts were studied for their efficiency in producing SLCTs. Results showed that Novozyme 435 was more suitable for this reaction system. Moreover, the optimal reaction conditions for the highest conversion of FAMEs and the highest LLS-TAGs (triacylglycerols with one short- and two long-chain acyl residues) yields were achieved at a molar ratio of FAMEs to triacetin of 3:1, 50 °C of reaction temperature and a lipase amount of 4% (w/v). Scale-up was conducted based on the optimized reaction conditions. Results showed that after 24 h of reaction , the conversion rate of FAMEs was 82.4% and the rate of disubstituted triacetin was 52.4 mol%. The final product yield rate was 94.6%. The effects of the synthesized SLCTs on the plasma lipid level of fasting mice were also studied. The SLCTs could effectively lessen the total triacylglycerol levels in plasma compared to the triacylglycerol group in fasting NIH mice. It suggested that this type of structured lipid might be beneficial for human health, especially for the prevention of obesity. Full article
Open AccessArticle In Situ Formation of Steroidal Supramolecular Gels Designed for Drug Release
Molecules 2013, 18(4), 3745-3759; doi:10.3390/molecules18043745
Received: 25 February 2013 / Revised: 19 March 2013 / Accepted: 21 March 2013 / Published: 25 March 2013
Cited by 7 | PDF Full-text (452 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In this work, a steroidal gelator containing an imine bond was synthesized, and its gelation behavior as well as a sensitivity of its gels towards acids was investigated. It was shown that the gels were acid-responsive, and that the gelator molecules could be
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In this work, a steroidal gelator containing an imine bond was synthesized, and its gelation behavior as well as a sensitivity of its gels towards acids was investigated. It was shown that the gels were acid-responsive, and that the gelator molecules could be prepared either by a conventional synthesis or directly in situ during the gel forming process. The gels prepared by both methods were studied and it was found that they had very similar macro- and microscopic properties. Furthermore, the possibility to use the gels as carriers for aromatic drugs such as 5-chloro-8-hydroxyquinoline, pyrazinecarboxamide, and antipyrine was investigated and the prepared two-component gels were studied with regard to their potential applications in drug delivery, particularly in a pH-controlled drug release. Full article
(This article belongs to the Special Issue Steroids)
Open AccessArticle Comparing the Suitability of Autodock, Gold and Glide for the Docking and Predicting the Possible Targets of Ru(II)-Based Complexes as Anticancer Agents
Molecules 2013, 18(4), 3760-3778; doi:10.3390/molecules18043760
Received: 19 February 2013 / Revised: 7 March 2013 / Accepted: 18 March 2013 / Published: 25 March 2013
Cited by 7 | PDF Full-text (614 KB) | HTML Full-text | XML Full-text
Abstract
In cancer chemotherapy, metal-based complexes have been recognized as the most promising means of inhibiting cancer growth due to the successful application of cis-platin and its derivatives above many of the existing organic anticancer agents. The limitations in their rational design can
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In cancer chemotherapy, metal-based complexes have been recognized as the most promising means of inhibiting cancer growth due to the successful application of cis-platin and its derivatives above many of the existing organic anticancer agents. The limitations in their rational design can be traced to the complexity of the mechanism of their operations, lack of proper knowledge of their targets and lack of force fields in docking packages to appropriately define the metal centre of the organometallic complexes. In this paper, some of the promising anticancer complexes of Ru(II) such as the rapta-based complexes formulated as [Ru(η6-p-cymene)L2(pta)] and those with unusual ligands are considered. CatB and kinases which have been experimentally confirmed as possible targets of the complexes are also predicted by the three methods as one of the most targeted receptors while TopII and HDAC7 are predicted by two and one of the methods as best targets. The interesting features of the binding of the complexes show that some of the complexes preferentially target specific macromolecules than the others, which is an indication of their specificity and possibility of their therapeutic combination without severe side effects that may come from competition for the same target. Also, introduction of unusual ligands is found to significantly improve the activities of most of the complexes studied. Strong correlations are observed for the predicted binding sites and the orientation of the complexes within the binding site by the three methods of docking. However there are disparities in the ranking of the complexes by the three method of docking, especially that of Glide. Full article
Open AccessArticle Cholinesterase Enzymes Inhibitors from the Leaves of Rauvolfia Reflexa and Their Molecular Docking Study
Molecules 2013, 18(4), 3779-3788; doi:10.3390/molecules18043779
Received: 19 February 2013 / Revised: 19 March 2013 / Accepted: 20 March 2013 / Published: 25 March 2013
Cited by 6 | PDF Full-text (373 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Plants of the Apocynaceae family have been traditionally used in the treatment of age-related brain disorders. Rauvolfia reflexa, a member of the family, has been used as an antidote for poisons and to treat malaria. The dichloromethane, ethanol and methanol extracts from
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Plants of the Apocynaceae family have been traditionally used in the treatment of age-related brain disorders. Rauvolfia reflexa, a member of the family, has been used as an antidote for poisons and to treat malaria. The dichloromethane, ethanol and methanol extracts from the leaves of Rauvolfia reflexa showed potential acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities, with IC50 values in the 8.49 to 52.23 g/mL range. Further cholinesterase inhibitory-guided isolation of these extracts afforded four bioactive compounds, namely: (E)-3-(3,4,5-trimethoxyphenyl)acrylic acid (1), (E)-methyl 3-(4-hydroxy-3,5-dimethoxyphenyl) acrylate (2), 17-methoxycarbonyl-14-heptadecaenyl-4-hydroxy-3-methoxycinnamate (3) and 1,2,3,4-tetrahydro-1-oxo-β-carboline (4). The isolated compounds showed moderate cholinesterase inhibitory activity compared to the reference standard, physostigmine. Compounds 1 and 2 showed the highest inhibitory activity against AChE (IC50 = 60.17 µM) and BChE (IC50 = 61.72 µM), respectively. Despite having similar molecular weight, compounds 1 and 2 were structurally different according to their chemical substitution patterns, leading to their different enzyme inhibition selectivity. Compound 2 was more selective against BChE, whereas compound 1 was a selective inhibitor of AChE. Molecular docking revealed that both compounds 1 and 2 were inserted, but not deeply into the active site of the cholinesterase enzymes. Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessArticle Synthesis and Anti-Influenza Virus Activities of a Novel Class of Gastrodin Derivatives
Molecules 2013, 18(4), 3789-3805; doi:10.3390/molecules18043789
Received: 16 February 2013 / Revised: 19 March 2013 / Accepted: 20 March 2013 / Published: 26 March 2013
Cited by 4 | PDF Full-text (413 KB) | HTML Full-text | XML Full-text
Abstract
A series of substituted aryl glycoside analogues of gastrodin have been identified as potential anti-influenza agents. The most potent inhibitor 1a exhibited moderate inhibitory activity against the A/Hanfang/359/95(H3N2) and A/FM/1/47(H1N1) strains of the influenza A virus (IC50 values of 44.40 and 34.45
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A series of substituted aryl glycoside analogues of gastrodin have been identified as potential anti-influenza agents. The most potent inhibitor 1a exhibited moderate inhibitory activity against the A/Hanfang/359/95(H3N2) and A/FM/1/47(H1N1) strains of the influenza A virus (IC50 values of 44.40 and 34.45 μM, respectively) and the oseltamivir-null B/Jifang/13/97 strain of influenza B (IC50 value of 33.01 μM). In this article, multiple doses of compound 1a (80 mg/kg/day, oral administration) were used for the treatment of mice infected with influenza A/FM/1/47-MA (H1N1), and surprisingly we found that compound 1a significantly increased the number of survivors and prolonged the mean survival time. The preliminary studies on the mechanism of antiviral activity showed no interaction between compound 1a and the neuraminidase or the M2 protein. The novel target to overcome drug resistance combined with its good in vivo profile support compound 1a to be a new lead for further development of antiviral agents. Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessArticle First-Principles Elucidation of the Surface Chemistry of the C2Hx (x = 0–6) Adsorbate Series on Fe(100)
Molecules 2013, 18(4), 3806-3824; doi:10.3390/molecules18043806
Received: 20 February 2013 / Revised: 18 March 2013 / Accepted: 21 March 2013 / Published: 26 March 2013
Cited by 9 | PDF Full-text (1365 KB) | HTML Full-text | XML Full-text
Abstract
Ab initio total-energy calculations of the elementary reaction steps leading to acetylene, ethylene and ethane formation and their decomposition on Fe(100) are described. Alongside the endothermicity of all the formation reactions, the crucial role played by adsorbed ethyl as main precursor towards both
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Ab initio total-energy calculations of the elementary reaction steps leading to acetylene, ethylene and ethane formation and their decomposition on Fe(100) are described. Alongside the endothermicity of all the formation reactions, the crucial role played by adsorbed ethyl as main precursor towards both ethylene and ethane formation, characterises Fe(100) surface reactivity towards C2Hx (x = 0–6) hydrocarbon formation in the low coverage limit. A comprehensive scheme based on three viable mechanisms towards ethyl formation on Fe(100), including methyl/methylene coupling, methyl/methylidyne coupling followed by one hydrogenation and methyl/carbon coupling followed by two hydrogenations, is the main result of this article. Full article
(This article belongs to the Special Issue Computational Chemistry)
Open AccessArticle Effects of Freshwater Clam Extract Supplementation on Time to Exhaustion, Muscle Damage, Pro/Anti-Inflammatory Cytokines, and Liver Injury in Rats after Exhaustive Exercise
Molecules 2013, 18(4), 3825-3838; doi:10.3390/molecules18043825
Received: 5 February 2013 / Revised: 22 March 2013 / Accepted: 22 March 2013 / Published: 26 March 2013
Cited by 5 | PDF Full-text (546 KB) | HTML Full-text | XML Full-text
Abstract
The potent anti-inflammatory activities and tissue-protective effects of freshwater clams (Corbicula fluminea) have been well reported. The aim of this study was to determine the effects of freshwater clam extract (FCE) supplementation on time to exhaustion, muscle damage, pro- and anti-inflammatory
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The potent anti-inflammatory activities and tissue-protective effects of freshwater clams (Corbicula fluminea) have been well reported. The aim of this study was to determine the effects of freshwater clam extract (FCE) supplementation on time to exhaustion, muscle damage, pro- and anti-inflammatory cytokines, and liver injury in rats after exhaustive exercise. Thirty-two rats were divided into four groups: sedentary control (SC); SC group with FCE supplementation (SC+FCE); exhaustive exercise (E); and E group with FCE supplementation (E+FCE). The SC+FCE and E+FCE groups were treated with gavage administration of 20 mg/kg for seven consecutive days. Blood samples were collected for the evaluation of biochemical parameters. The cytokine levels of TNF-α and IL-10 were also examined. Twenty-four hours after exhaustive exercise, the rat livers were removed for H & E staining. The FCE supplementation could extend the time to exhaustion in exercised rats. The levels of CPK, LDH, AST, ALT, lactate, TNF-α and H & E stains of the liver injury were significantly decreased in the E+FCE group, but the blood glucose and IL-10 were significantly higher in comparison with the E group. This study suggests that FCE supplementation may improve endurance performance and reduce exercise-induced muscle damage, inflammatory stress and liver injury. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Phenylmethimazole Suppresses dsRNA-Induced Cytotoxicity and Inflammatory Cytokines in Murine Pancreatic Beta Cells and Blocks Viral Acceleration of Type 1 Diabetes in NOD Mice
Molecules 2013, 18(4), 3841-3858; doi:10.3390/molecules18043841
Received: 16 February 2013 / Revised: 28 February 2013 / Accepted: 22 March 2013 / Published: 27 March 2013
Cited by 7 | PDF Full-text (520 KB) | HTML Full-text | XML Full-text
Abstract
Accumulating evidence supports a role for viruses in the pathogenesis of type 1 diabetes mellitus (T1DM). Activation of dsRNA-sensing pathways by viral dsRNA induces the production of inflammatory cytokines and chemokines that trigger beta cell apoptosis, insulitis, and autoimmune-mediated beta cell destruction. This
[...] Read more.
Accumulating evidence supports a role for viruses in the pathogenesis of type 1 diabetes mellitus (T1DM). Activation of dsRNA-sensing pathways by viral dsRNA induces the production of inflammatory cytokines and chemokines that trigger beta cell apoptosis, insulitis, and autoimmune-mediated beta cell destruction. This study was designed to evaluate and describe potential protective effects of phenylmethimazole (C10), a small molecule which blocks dsRNA-mediated signaling, on preventing dsRNA activation of beta cell apoptosis and the inflammatory pathways important in the pathogenesis of T1DM. We first investigated the biological effects of C10, on dsRNA-treated pancreatic beta cells in culture. Cell viability assays, quantitative real-time PCR, and ELISAs were utilized to evaluate the effects of C10 on dsRNA-induced beta cell cytotoxicity and cytokine/chemokine production in murine pancreatic beta cells in culture. We found that C10 significantly impairs dsRNA-induced beta cell cytotoxicity and up-regulation of cytokines and chemokines involved in the pathogenesis of T1DM, which prompted us to evaluate C10 effects on viral acceleration of T1DM in NOD mice. C10 significantly inhibited viral acceleration of T1DM in NOD mice. These findings demonstrate that C10 (1) possesses novel beta cell protective activity which may have potential clinical relevance in T1DM and (2) may be a useful tool in achieving a better understanding of the role that dsRNA-mediated responses play in the pathogenesis of T1DM. Full article
Open AccessArticle HPLC-DAD-ESI/MS Identification and Quantification of Phenolic Compounds in Ilex paraguariensis Beverages and On-Line Evaluation of Individual Antioxidant Activity
Molecules 2013, 18(4), 3859-3871; doi:10.3390/molecules18043859
Received: 27 December 2012 / Revised: 19 March 2013 / Accepted: 20 March 2013 / Published: 28 March 2013
Cited by 15 | PDF Full-text (318 KB) | HTML Full-text | XML Full-text
Abstract
“Chimarrão” and “tererê” are maté (dried, toasted and milled Ilex paraguariensis leaves and stemlets) beverages widely consumed in South America. This paper describes the application of HPLC-DAD-ESI/MS method for the identification and quantification of caffeoylquinic acids (CQA), flavonol glycosides and purine alkaloids in
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“Chimarrão” and “tererê” are maté (dried, toasted and milled Ilex paraguariensis leaves and stemlets) beverages widely consumed in South America. This paper describes the application of HPLC-DAD-ESI/MS method for the identification and quantification of caffeoylquinic acids (CQA), flavonol glycosides and purine alkaloids in these beverages. The beverage samples were prepared from commercial lots of maté from Southern Brazil. The caffeoylquinic acids, 4,5-diCQA, 3-CQA, 5-CQA, and 4-CQA were the major compounds, having 238–289, 153–242, 183–263, and 123–188 μg/mL, respectively, for chimarrão and 206–265, 122–218, 164–209, 103–169 μg/mL, respectively, for tererê. Caffeine also had high amounts while glycosides of quercetin and kaempferol were found at much lower levels. The individual antioxidant activity was also determined by an on-line system that measured their ABTS•+ radical scavenging activity, showing that the antioxidant capacity was not proportional to the concentrations of the phenolic compounds. 3-CQA, quercetina-3-O-ramnosylglucoside, and quercetina-3-O-glucoside were the major contributors to the antioxidant capacity, although the quercetin glycosides had concentrations less than 10 times that of 3-CQA. Full article
(This article belongs to the Special Issue Methods in Polyphenol Analysis)
Open AccessArticle Synthesis, in Vitro Antimycobacterial and Antibacterial Evaluation of IMB-070593 Derivatives Containing a Substituted Benzyloxime Moiety
Molecules 2013, 18(4), 3872-3893; doi:10.3390/molecules18043872
Received: 20 February 2013 / Revised: 21 March 2013 / Accepted: 22 March 2013 / Published: 28 March 2013
Cited by 2 | PDF Full-text (306 KB) | HTML Full-text | XML Full-text
Abstract
A series of novel IMB-070593 derivatives containing a substituted benzyloxime moiety and displaying a remarkable improvement in lipophilicity were synthesized and evaluated for their in vitro antimycobacterial and antibacterial activity. Our results reveal that the target compounds 19am have considerable Gram-positive
[...] Read more.
A series of novel IMB-070593 derivatives containing a substituted benzyloxime moiety and displaying a remarkable improvement in lipophilicity were synthesized and evaluated for their in vitro antimycobacterial and antibacterial activity. Our results reveal that the target compounds 19am have considerable Gram-positive activity (MIC: <0.008–32 µg/mL), although they are generally less active than the reference drugs against the Gram-negative strains. In particular, compounds 19h, 19j, 19k and 19m show good activity (MICs: <0.008–4 µg/mL) against all of the tested Gram-positive strains, including ciprofloxacin (CPFX)- and/or levofloxacin (LVFX)-resistant MSSA, MRSA and MSSE. Moreover, compound 19l (MIC: 0.125 µg/mL) is found to be 2–4 fold more active than the parent IMB070593, CPFX and LVFX against M. tuberculosis H37Rv ATCC 27294. Full article
Open AccessArticle Lanthanide-Mediated Dephosphorylation Used for Peptide Cleavage during Solid Phase Peptide Synthesis
Molecules 2013, 18(4), 3894-3905; doi:10.3390/molecules18043894
Received: 28 January 2013 / Revised: 27 February 2013 / Accepted: 27 March 2013 / Published: 2 April 2013
Cited by 1 | PDF Full-text (303 KB) | HTML Full-text | XML Full-text
Abstract
Lanthanide(III) ions can accelerate the hydrolysis of phosphomonoesters and phosphodiesters in neutral aqueous solution. In this paper, lanthanide-mediated dephosphorylation has been applied in aqueous media as an orthogonal cleavage condition that can be employed in conventional solid phase peptide synthesis (SPPS). A phosphorylated
[...] Read more.
Lanthanide(III) ions can accelerate the hydrolysis of phosphomonoesters and phosphodiesters in neutral aqueous solution. In this paper, lanthanide-mediated dephosphorylation has been applied in aqueous media as an orthogonal cleavage condition that can be employed in conventional solid phase peptide synthesis (SPPS). A phosphorylated polymeric support for SPPS was developed using Boc chemistry. The cleavage of resin-bound phosphates was investigated with the addition of Eu(III), Yb(III), acid or base, a mixture of solvents or different temperatures. To demonstrate the utility of this approach for SPPS, a peptide sequence was synthesized on a phosphorylated polymeric support and quantitatively cleaved with lanthanide ions in neutral aqueous media. The protecting groups for side chains were retained during peptide cleavage using lanthanide ions. This new methodology provides a mild orthogonal cleavage condition of phosphoester as a linker during SPPS. Full article
(This article belongs to the Special Issue Chemical Protein and Peptide Synthesis)
Open AccessArticle Synthesis of a Pseudodisaccharide α-C-Glycosidically Linked to an 8-Alkylated Guanine
Molecules 2013, 18(4), 3906-3916; doi:10.3390/molecules18043906
Received: 25 February 2013 / Revised: 21 March 2013 / Accepted: 21 March 2013 / Published: 2 April 2013
PDF Full-text (324 KB) | HTML Full-text | XML Full-text
Abstract
The synthesis of stable guanofosfocin analogues has attracted considerable attention in the past 15 years. Several guanofosfocin analogues mimicking the three constitutional elements of mannose, ribose, and guanine were designed and synthesized. Interest in ether-linked pseudodisaccharides and 8-alkylated guanines is increasing, due to
[...] Read more.
The synthesis of stable guanofosfocin analogues has attracted considerable attention in the past 15 years. Several guanofosfocin analogues mimicking the three constitutional elements of mannose, ribose, and guanine were designed and synthesized. Interest in ether-linked pseudodisaccharides and 8-alkylated guanines is increasing, due to their potential applications in life science. In this article, a novel guanofosfocin analogue 6, an ether-linked pseudodisaccharide connected α-C-glycosidically to an 8-alkylated guanine, was synthesized in a 10-longest linear step sequence from known diol 13, resulting in an overall yield of 26%. The key steps involve the ring-opening of cyclic sulfate 8 by alkoxide generated from 7 and a reductive cyclization of 4-N-acyl-2,4-diamino-5-nitrosopyrimidine 19 to form compound 6. Full article
(This article belongs to the Section Organic Synthesis)
Open AccessArticle Bisucaberin B, a Linear Hydroxamate Class Siderophore from the Marine Bacterium Tenacibaculum mesophilum
Molecules 2013, 18(4), 3917-3926; doi:10.3390/molecules18043917
Received: 16 February 2013 / Revised: 11 March 2013 / Accepted: 22 March 2013 / Published: 2 April 2013
Cited by 7 | PDF Full-text (342 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A siderophore, named bisucaberin B, was isolated from Tenacibaculum mesophilum bacteria separated from a marine sponge collected in the Republic of Palau. Using spectroscopic and chemical methods, the structure of bisucaberin B (1) was clearly determined to be a linear dimeric
[...] Read more.
A siderophore, named bisucaberin B, was isolated from Tenacibaculum mesophilum bacteria separated from a marine sponge collected in the Republic of Palau. Using spectroscopic and chemical methods, the structure of bisucaberin B (1) was clearly determined to be a linear dimeric hydroxamate class siderophore. Although compound 1 is an open form of the known macrocyclic dimer bisucaberin (2), and was previously described as a bacterial degradation product of desferrioxamine B (4), the present report is the first description of the de novo biosynthesis of 1. To the best of our knowledge, compound 1 is the first chemically characterized siderophore isolated from a bacterium belonging to the phylum Bacteroidetes. Full article
(This article belongs to the Section Natural Products)
Figures

Open AccessArticle Volatile and Amino Acid Profiling of Dry Cured Hams from Different Swine Breeds and Processing Methods
Molecules 2013, 18(4), 3927-3947; doi:10.3390/molecules18043927
Received: 27 February 2013 / Revised: 28 March 2013 / Accepted: 28 March 2013 / Published: 3 April 2013
Cited by 2 | PDF Full-text (511 KB) | HTML Full-text | XML Full-text
Abstract
The flavor of dry cured ham explains the high appreciation of this product and it determines consumer acceptance. Volatile compounds provide valuable information about the odor and sensory quality of dry cured hams. Since amino acids are the origin of some volatile compounds
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The flavor of dry cured ham explains the high appreciation of this product and it determines consumer acceptance. Volatile compounds provide valuable information about the odor and sensory quality of dry cured hams. Since amino acids are the origin of some volatile compounds of dry cured ham, the volatile and amino acid compositions of forty-one dry cured hams from Spain and France were determined to establish associations between them. The samples included different pig breeds (non Iberian vs. Iberian), which were additionally affected by different maturation times and feeding types (acorn vs. fodder). Results showed that 20 volatile compounds were able to distinguish Iberian and non Iberian hams, and 16 of those had relevant sensory impact according to their odor activity values. 3-Methylbutanol, 2-heptanol and hexanal were among the most concentrated volatile compounds. In the case of non-volatile compounds, the concentrations of amino acids were generally higher in Iberian hams, and all the amino acids were able to distinguish Iberian from non Iberian hams with the exception of tryptophan and asparagine. A strong correlation of some amino acids with volatile compounds was found in the particular case of alcohols and aldehydes when only Iberian hams were considered. The high correlation values found in some cases proved that proteolysis plays an important role in aroma generation. Full article
(This article belongs to the Special Issue Flavors and Fragrances)
Open AccessArticle Synthesis and Biological Evaluation of Unsymmetrical Curcumin Analogues as Tyrosinase Inhibitors
Molecules 2013, 18(4), 3948-3961; doi:10.3390/molecules18043948
Received: 31 January 2013 / Revised: 14 March 2013 / Accepted: 22 March 2013 / Published: 3 April 2013
Cited by 8 | PDF Full-text (378 KB) | HTML Full-text | XML Full-text
Abstract
Synthesis and biological evaluation of unsymmetrical curcumin analogues (UCAs) have been achieved. Tyrosinase inhibitory activities were found for most of the prepared synthetic UCAs. Among them, compounds containing 4-hydroxyl-substituted phenolic rings with C-2/C-4- or C-3/C-4-dihydroxyl-substituted diphenolic rings
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Synthesis and biological evaluation of unsymmetrical curcumin analogues (UCAs) have been achieved. Tyrosinase inhibitory activities were found for most of the prepared synthetic UCAs. Among them, compounds containing 4-hydroxyl-substituted phenolic rings with C-2/C-4- or C-3/C-4-dihydroxyl-substituted diphenolic rings were more active (IC50 = 1.74~16.74 μM) than 4-butylresorcinol and kojic acid, which suggested that the 4-hydroxyl groups in UCAs play a crucial role in tyrosinase inhibitory activities. The inhibition kinetics analyzed by Lineweaver-Burk plots revealed compounds 3c and 3i containing catecholic rings were mixed-competitive inhibitors, whereas compounds 3d and 3j containing resorcinolic rings were competitive inhibitors. The preliminary evaluation results of acute toxicity showed the representative 3d and 3j were non-toxic in mice dosed at 1,200 mg/kg. This research suggests that, with the advantage of being readily prepared small molecules, polyphenolic UCAs have the potential to develop into pharmacological inhibitors of tyrosinase. Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessCommunication Macrocyclic Spermidine Alkaloids from Androya decaryi L. Perrier
Molecules 2013, 18(4), 3962-3971; doi:10.3390/molecules18043962
Received: 18 February 2013 / Revised: 28 March 2013 / Accepted: 29 March 2013 / Published: 4 April 2013
Cited by 1 | PDF Full-text (275 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Three new spermidine alkaloids and two known compounds were isolated from the leaves of Androya decaryi. Their structures were elucidated on the basis of their spectroscopic data (NMR and mass spectrometry), by X-Ray diffraction and by comparison with literature values. Evaluation of
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Three new spermidine alkaloids and two known compounds were isolated from the leaves of Androya decaryi. Their structures were elucidated on the basis of their spectroscopic data (NMR and mass spectrometry), by X-Ray diffraction and by comparison with literature values. Evaluation of the in vitro antiplamosdial properties of the isolated compounds revealed they did not possess any significant activity. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Design, Synthesis, Binding and Docking-Based 3D-QSAR Studies of 2-Pyridylbenzimidazoles—A New Family of High Affinity CB1 Cannabinoid Ligands
Molecules 2013, 18(4), 3972-4001; doi:10.3390/molecules18043972
Received: 26 February 2013 / Revised: 24 March 2013 / Accepted: 1 April 2013 / Published: 4 April 2013
Cited by 7 | PDF Full-text (729 KB) | HTML Full-text | XML Full-text
Abstract
A series of novel 2-pyridylbenzimidazole derivatives was rationally designed and synthesized based on our previous studies on benzimidazole 14, a CB1 agonist used as a template for optimization. In the present series, 21 compounds displayed high affinities with Ki values in
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A series of novel 2-pyridylbenzimidazole derivatives was rationally designed and synthesized based on our previous studies on benzimidazole 14, a CB1 agonist used as a template for optimization. In the present series, 21 compounds displayed high affinities with Ki values in the nanomolar range. JM-39 (compound 39) was the most active of the series (KiCB1 = 0.53 nM), while compounds 31 and 44 exhibited similar affinities to WIN 55212-2. CoMFA analysis was performed based on the biological data obtained and resulted in a statistically significant CoMFA model with high predictive value (q2 = 0.710, r2 = 0.998, r2pred = 0.823). Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessArticle Effect of a Combination of Low Level Ozone and Metal Ions on Reducing Escherichia coli O157:H7 and Listeria monocytogenes
Molecules 2013, 18(4), 4018-4025; doi:10.3390/molecules18044018
Received: 16 February 2013 / Revised: 1 April 2013 / Accepted: 1 April 2013 / Published: 4 April 2013
PDF Full-text (177 KB) | HTML Full-text | XML Full-text
Abstract
Ozonated water has been used as a strong antimicrobial agent against foodborne pathogens. In this study, the combined effect of low level ozonated water and different added components, including 0.2% starch and metal ions (1 mM CuCl2·2H2O and 0.1
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Ozonated water has been used as a strong antimicrobial agent against foodborne pathogens. In this study, the combined effect of low level ozonated water and different added components, including 0.2% starch and metal ions (1 mM CuCl2·2H2O and 0.1 mM AgNO3), on inactivation of Escherichia coli O157:H7 and Listeria monocytogenes was investigated. Treatment with 0.4 ppm ozonated water for 30 min resulted in a maximum log reduction in E. coli O157:H7 and L. monocytogenes compared to initial bacterial counts. The log reductions of bacteria in a starch solution containing ozonated water were slightly higher than those in ozonated water alone. Furthermore, the log reductions of E. coli O157:H7 (2.59 and 4.71 log cfu/mL) and L. monocytogenes (2.53 and 4.28 log cfu/mL) in a metal ion solution containing 0.2 and 0.4 ppm ozone for 30 min were significantly higher than those of the water and starch added groups (p < 0.05). These results indicate that a combination of ozonated water and metal ions may be useful as a antimicrobial agent. Full article
Open AccessArticle A Selenium-Based Ionic Liquid as a Recyclable Solvent for the Catalyst-Free Synthesis of 3-Selenylindoles
Molecules 2013, 18(4), 4081-4090; doi:10.3390/molecules18044081
Received: 18 February 2013 / Revised: 28 March 2013 / Accepted: 2 April 2013 / Published: 5 April 2013
Cited by 8 | PDF Full-text (214 KB) | HTML Full-text | XML Full-text
Abstract
The ionic liquid 1-butyl-3-methylimidazolium methylselenite, [bmim][SeO2(OCH3)], was successfully used as solvent in the catalyst-free preparation of 3-arylselenylindoles by the reaction of indole with ArSeCl at room temperature. The products were obtained selectively in good yields without the need of
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The ionic liquid 1-butyl-3-methylimidazolium methylselenite, [bmim][SeO2(OCH3)], was successfully used as solvent in the catalyst-free preparation of 3-arylselenylindoles by the reaction of indole with ArSeCl at room temperature. The products were obtained selectively in good yields without the need of any additive and the solvent was easily reused for several cycles with good results. Full article
(This article belongs to the Special Issue Selenium and Tellurium Chemistry)
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Open AccessArticle Combinatorial Techniques to Efficiently Investigate and Optimize Organic Thin Film Processing and Properties
Molecules 2013, 18(4), 4120-4139; doi:10.3390/molecules18044120
Received: 9 January 2013 / Revised: 2 April 2013 / Accepted: 3 April 2013 / Published: 8 April 2013
PDF Full-text (1441 KB) | HTML Full-text | XML Full-text
Abstract
In this article we present several developed and improved combinatorial techniques to optimize processing conditions and material properties of organic thin films. The combinatorial approach allows investigations of multi-variable dependencies and is the perfect tool to investigate organic thin films regarding their high
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In this article we present several developed and improved combinatorial techniques to optimize processing conditions and material properties of organic thin films. The combinatorial approach allows investigations of multi-variable dependencies and is the perfect tool to investigate organic thin films regarding their high performance purposes. In this context we develop and establish the reliable preparation of gradients of material composition, temperature, exposure, and immersion time. Furthermore we demonstrate the smart application of combinations of composition and processing gradients to create combinatorial libraries. First a binary combinatorial library is created by applying two gradients perpendicular to each other. A third gradient is carried out in very small areas and arranged matrix-like over the entire binary combinatorial library resulting in a ternary combinatorial library. Ternary combinatorial libraries allow identifying precise trends for the optimization of multi-variable dependent processes which is demonstrated on the lithographic patterning process. Here we verify conclusively the strong interaction and thus the interdependency of variables in the preparation and properties of complex organic thin film systems. The established gradient preparation techniques are not limited to lithographic patterning. It is possible to utilize and transfer the reported combinatorial techniques to other multi-variable dependent processes and to investigate and optimize thin film layers and devices for optical, electro-optical, and electronic applications. Full article
(This article belongs to the Special Issue Combinatorial Synthesis)
Open AccessArticle Synthesis and Biological Evaluation of New 2-Azetidinones with Sulfonamide Structures
Molecules 2013, 18(4), 4140-4157; doi:10.3390/molecules18044140
Received: 26 February 2013 / Revised: 26 March 2013 / Accepted: 3 April 2013 / Published: 8 April 2013
Cited by 9 | PDF Full-text (222 KB) | HTML Full-text | XML Full-text
Abstract
New series of N-(arylidene)hydrazinoacetyl sulfonamides 4a16, 4b16 and N-(4-aryl-3-chloro-2-oxoazetidin-1-yl)aminoacetyl sulfonamides 5a16, 5b16 were synthesized. The structures of the new derivatives was confirmed using spectral methods (FT-IR, 1
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New series of N-(arylidene)hydrazinoacetyl sulfonamides 4a16, 4b16 and N-(4-aryl-3-chloro-2-oxoazetidin-1-yl)aminoacetyl sulfonamides 5a16, 5b16 were synthesized. The structures of the new derivatives was confirmed using spectral methods (FT-IR, 1H-NMR, 13C-NMR). The antibacterial activities of these compounds against Gram positive (Staphyloccoccus aureus ATCC 6583, Staphyloccoccus epidermidis ATCC 12228, Enterococcus faecalis ATCC 25912) and Gram negative (Klebsiella pneumoniae CIP 53153, Proteus vulgaris CIP 104989, Citrobacter freundii CIP 5732, Enterobacter cloacae CIP 103475, Escherichia coli ATCC 25922, Pseudomonas aeruginosa CIP 82118) bacterial strains were evaluated using the broth micro-dilution method. Compound 4a2 displayed the highest antibacterial activity, especially against Staphyloccoccus epidermidis, Enterococcus faecalis and Pseudomonas aeruginosa. The antioxidant potential of the synthesized compounds was also investigated according to ferric reducing power, total antioxidant activity and DPPH radical scavenging assays. All tested compounds showed excellent antioxidant activity in comparison with sulfadiazine and sulfisoxazole which were used as parent sulfonamides. Moreover, some of them showed an antioxidant activity comparable with that of ascorbic acid. In general, the compounds designed based on a sulfadiazine skeleton (compounds 4a1–6, 5a1–6) are more active than those obtained from sulfisoxazole (compounds 4b1–6, 5b1–6), and the N-(arylidene)hydrazinoacetyl sulfonamide derivatives 4a16, 4b16 are more active than their azetidionone analogues 5a16, 5b16. Full article
Open AccessArticle Design, Synthesis and Antitumor Activity of Novel 4-Methyl-(3'S,4'S)-cis-khellactone Derivatives
Molecules 2013, 18(4), 4158-4169; doi:10.3390/molecules18044158
Received: 16 February 2013 / Revised: 27 March 2013 / Accepted: 2 April 2013 / Published: 8 April 2013
Cited by 3 | PDF Full-text (210 KB) | HTML Full-text | XML Full-text
Abstract
An asymmetric synthesis of a series of novel 4-methyl-(3'S,4'S)-cis-khellactone derivatives 3ao is reported for the first time. Their structures were confirmed by 1H-NMR, 13C-NMR and MS. Their cytotoxic activity was evaluated by the
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An asymmetric synthesis of a series of novel 4-methyl-(3'S,4'S)-cis-khellactone derivatives 3ao is reported for the first time. Their structures were confirmed by 1H-NMR, 13C-NMR and MS. Their cytotoxic activity was evaluated by the MTT assay against three selected human cancer cell lines: HEPG-2 (human liver carcinoma), SGC-7901 (human gastric carcinoma), LS174T (human colon carcinoma). Some compounds showed high inhibitory activity against these human cancer cell lines. Among them, compound 3a exhibited strong cytotoxicity, with IC50 values ranging from 8.51 to 29.65 μM. The results showed that 4-methyl-cis-khellactone derivatives with S,S configuration could be a potential antitumor agents. Full article
Open AccessArticle Chemical Composition and Nematicidal Activity of Essential Oil of Agastache rugosa against Meloidogyne incognita
Molecules 2013, 18(4), 4170-4180; doi:10.3390/molecules18044170
Received: 26 February 2013 / Revised: 2 April 2013 / Accepted: 3 April 2013 / Published: 9 April 2013
Cited by 13 | PDF Full-text (173 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this research was to determine the chemical composition and nematicidal activity of essential oil of Agastache rugosa flowering aerial parts against the root knot nematode, Meloidogyne incognita, and to isolate and identify any nematicidal constituents from the essential oil.
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The aim of this research was to determine the chemical composition and nematicidal activity of essential oil of Agastache rugosa flowering aerial parts against the root knot nematode, Meloidogyne incognita, and to isolate and identify any nematicidal constituents from the essential oil. The essential oil of A. rugosa aerial parts was obtained by hydrodistillation and analyzed by GC-FID and GC-MS. A total of 37 components of the essential oil were identified, with the principal compounds being methyleugenol (50.51%), estragole (8.55%), and eugenol (7.54%), followed by thymol (3.62%), pulegone (2.56%), limonene (2.49%) and caryophyllene (2.38%). Based on bioactivity-guided fractionation, the three active constituents were isolated from the essential oil and identified as methyleugenol, estragole and eugenol. The essential oil of A. rugosa exhibited strong nematicidal activity against M. incognita, with a LC50 value of 47.3 μg/mL. The components eugenol (LC50 = 66.6 μg/mL) and methyleugenol (LC50 = 89.4 μg/mL) exhibited stronger nematicidal activity against M. incognita (LC50 = 185.9 μg/mL). The results indicate that the essential oil of A. rugosa aerial parts and its constituent compounds have potential for development into natural nematicides for control of the root knot nematode. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Yellow Pigments, Fomitellanols A and B, and Drimane Sesquiterpenoids, Cryptoporic Acids P and Q, from Fomitella fraxinea and Their Inhibitory Activity against COX and 5-LO
Molecules 2013, 18(4), 4181-4191; doi:10.3390/molecules18044181
Received: 25 February 2013 / Revised: 28 March 2013 / Accepted: 4 April 2013 / Published: 9 April 2013
Cited by 3 | PDF Full-text (276 KB) | Supplementary Files
Abstract
Yellow pigments, fomitellanols A (1a) and B (2a), and drimane-type sesquiterpenoid ethers of isocitric acid, cryptoporic acids P (3) and Q (4), have been isolated from the fruiting bodies of Fomitella fraxinea (Polyporaceae). Their structures
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Yellow pigments, fomitellanols A (1a) and B (2a), and drimane-type sesquiterpenoid ethers of isocitric acid, cryptoporic acids P (3) and Q (4), have been isolated from the fruiting bodies of Fomitella fraxinea (Polyporaceae). Their structures were established by a combination of extensive NMR spectroscopy and/or X-ray crystallographic analyses, and their biological activity against COX-1, COX-2, and 5-LO was investigated. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Comparative Study on the Larvicidal Activity of Drimane Sesquiterpenes and Nordrimane Compounds against Drosophila melanogaster til-til
Molecules 2013, 18(4), 4192-4208; doi:10.3390/molecules18044192
Received: 16 February 2013 / Revised: 7 March 2013 / Accepted: 1 April 2013 / Published: 10 April 2013
Cited by 6 | PDF Full-text (287 KB) | HTML Full-text | XML Full-text
Abstract
Natural compounds from Drimys winteri Forst and derivatives exhibited larvicidal effects against Drosophila melanogaster til-til. The most active compound was isodrimenin (4). The highest lethal concentration to the larvae of D. melanogaster was 4.5 ± 0.8 mg/L. At very low
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Natural compounds from Drimys winteri Forst and derivatives exhibited larvicidal effects against Drosophila melanogaster til-til. The most active compound was isodrimenin (4). The highest lethal concentration to the larvae of D. melanogaster was 4.5 ± 0.8 mg/L. At very low concentrations drimenol (1), confertifolin (3), and drimanol (5) displayed antifeedant and larvae growth regulatory activity. The antifeedant results of nordrimanic and drimanic compounds were better in first instar larvae. The EC50 value of polygodial (2) was 60.0 ± 4.2 mg/L; of diol 15 45.0 ± 2.8 mg/L, and of diol 17 36.9 ± 3.7 mg/L, while the new nordrimane compound 12 presented a value of 83.2 ± 3.5 mg/L. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Peripheral Antinociception of a Chalcone, Flavokawin B and Possible Involvement of the Nitric Oxide/Cyclic Guanosine Monophosphate/Potassium Channels Pathway
Molecules 2013, 18(4), 4209-4220; doi:10.3390/molecules18044209
Received: 28 January 2013 / Revised: 28 March 2013 / Accepted: 28 March 2013 / Published: 10 April 2013
Cited by 2 | PDF Full-text (123 KB) | HTML Full-text | XML Full-text
Abstract
Previous studies have shown that systemic administration of 6'-hydroxy-2',4'-dimethoxychalcone (flavokawin B, FKB) exerts significant peripheral and central antinociceptive effects in laboratory animals. However, the mechanisms underlying these peripheral and central antinociceptive effects have yet to be elucidated. Therefore, the objective of the present
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Previous studies have shown that systemic administration of 6'-hydroxy-2',4'-dimethoxychalcone (flavokawin B, FKB) exerts significant peripheral and central antinociceptive effects in laboratory animals. However, the mechanisms underlying these peripheral and central antinociceptive effects have yet to be elucidated. Therefore, the objective of the present study was to evaluate the participation of nitric oxide (NO)/cyclic guanosine monophosphate (cGMP)/potassium (K+) channels pathway in the peripheral antinociception induced by FKB. It was demonstrated that intraplantar (i.pl.) administration of FKB (150, 250, 375 and 500 µg/paw) resulted in dose-dependent peripheral antinociception against mechanical hyperalgesia in carrageenan-induced hyperalgesia test model in rats. The possibility of FKB having either a central or a systemic effect was excluded since administration of FKB into the right paw did not elicit antinociception in the contralateral paw. Furthermore, peripheral antinociception induced by FKB (500 µg/paw) was significantly reduced when L-arginine (25 µg/paw, i.pl.), Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 50 µg/paw, i.pl.), glibenclamide (300 µg/paw, i.pl.), tetraethylammonium (300 µg/paw, i.pl.) and charybdotoxin (3 µg/paw, i.pl.) were injected before treatment. Taken together, our present data suggest that FKB elicits peripheral antinociception when assessed in the mechanical hyperalgesia induced by carrageenan. In addition, it was also demonstrated that this effect was mediated through interaction of the NO/cGMP/K+ channels signaling pathway. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle α-Glucosidase Inhibitory Effect and Simultaneous Quantification of Three Major Flavonoid Glycosides in Microctis folium
Molecules 2013, 18(4), 4221-4232; doi:10.3390/molecules18044221
Received: 13 March 2013 / Revised: 27 March 2013 / Accepted: 8 April 2013 / Published: 10 April 2013
Cited by 18 | PDF Full-text (619 KB) | HTML Full-text | XML Full-text
Abstract
Microctis Folium, the leaves of Microcos paniculata L., is a commonly used herbal tea material. The methanol extract of Microctis Folium and its principle compounds vitexin (1), isovitexin (2) and isorhamnetin 3-O-β-D-rutinoside (3
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Microctis Folium, the leaves of Microcos paniculata L., is a commonly used herbal tea material. The methanol extract of Microctis Folium and its principle compounds vitexin (1), isovitexin (2) and isorhamnetin 3-O-β-D-rutinoside (3) were investigated for their α-glucosidase inhibitory effects. The extract showed strong α-glucosidase inhibitory effect (IC50 = 61.30 μg/mL) and the three flavonoid glycosides 13 exerted satisfactory α-glucosidase inhibitory effects, with IC50 values of 244.0 μM, 266.2 μM and 275.4 μM, respectively. A simple and reliable HPLC-DAD method was developed for the quantification of the three flavonoid glycosides in Microctis Folium and applied successfully to determine contents of these components in samples collected from different locations. This study suggested that Microctis Folium may be a promising candidate for development of herbal antidiabetes drugs, and vitexin, isovitexin and isorhamnetin 3-O-β-D-rutinoside can be the biomarkers and chemical markers for this plant substance. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Effect of Erica sp. Honey against Microorganisms of Clinical Importance: Study of the Factors Underlying this Biological Activity
Molecules 2013, 18(4), 4233-4246; doi:10.3390/molecules18044233
Received: 18 February 2013 / Revised: 18 March 2013 / Accepted: 1 April 2013 / Published: 11 April 2013
Cited by 5 | PDF Full-text (221 KB) | HTML Full-text | XML Full-text
Abstract
This study aimed to determine the factors (phenolic compounds, flavonoids, sugars or H2O2) that contribute the most to the antimicrobial activity of heather honey samples against four yeasts and four bacteria with medical importance. To discard the effect of
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This study aimed to determine the factors (phenolic compounds, flavonoids, sugars or H2O2) that contribute the most to the antimicrobial activity of heather honey samples against four yeasts and four bacteria with medical importance. To discard the effect of H2O2 in the antimicrobial activity, catalase was added. To evaluate the osmotic pressure’s effect, artificial honey was also used. Phenolic compounds and flavonoids were determined and Pearson’s correlation analysis was performed to assess whether these correlated with antimicrobial activity. The amount of phenolic compounds ranged from 630.89 ± 5.21 GAE kg−1 to 718.92 ± 4.41 GAE kg−1, while the flavonoids varied between 450.72 ± 5.67 CAE kg−1 and 673.98 ± 4.33 CAE kg−1. For the bacteria, the minimum inhibitory concentration (MIC) of the honey without catalase ranged from 1.01 ± 0.50% to 10.00 ± 4.72% and was between 2.00 ± 0.94% and 13.27 ± 5.23% for honey with catalase. Concerning the yeasts, the MICs was between 13.16 ± 4.08% and 20.00 ± 5.09% for honey without catalase and between 14.95 ± 4.16% and 25.67 ± 5.50% for honey with catalase. The elucidation of the antimicrobial factors and action mechanisms is essential for the correct use of honey in therapeutic applications. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Triterpene Esters: Natural Products from Dorstenia arifolia (Moraceae)
Molecules 2013, 18(4), 4247-4256; doi:10.3390/molecules18044247
Received: 4 February 2013 / Revised: 7 April 2013 / Accepted: 8 April 2013 / Published: 11 April 2013
Cited by 11 | PDF Full-text (225 KB) | HTML Full-text | XML Full-text
Abstract
The phytochemical study of Dorstenia arifolia Lam. (Moraceae) has led to the identification of 18 triterpenes esterified by fatty acids, five triterpenes without esterification, 12 triterpenes esterified by acetic acid, together with a known furanocoumarin: α-amyrin (1), β-amyrin (2)
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The phytochemical study of Dorstenia arifolia Lam. (Moraceae) has led to the identification of 18 triterpenes esterified by fatty acids, five triterpenes without esterification, 12 triterpenes esterified by acetic acid, together with a known furanocoumarin: α-amyrin (1), β-amyrin (2) α-amyrin acetate (3) β-amyrin acetate (4), α-amyrin octanoate (5), β-amyrin octanoate (6), α-amyrin decanoate (7), β-amyrin decanoate (8), α-amyrin dodecanoate (9), β-amyrin dodecanoate (10), α-amyrin tetradecanoate (11), β-amyrin tetradecanoate (12), α-amyrin hexadecanoate (13), β-amyrin hexadecanoate (14), glutinol (15), glutinyl acetate (16), 11-oxo-α-amyrin (17), 11-oxo-β-amyrin (18), 11-oxo-α-amyrin acetate (19), 11-oxo-β-amyrin acetate (20) 11-oxo-α-amyrin octanoate (21) 11-oxo-β-amyrin octanoate (22), 11-oxo-α-amyrin decanoate (23), 11-oxo-β-amyrin decanoate (24) 11-oxo-α-amyrin dodecanoate (25) 11-oxo-β-amyrin dodecanoate (26), ursa-9(11),12-dien-3-yl acetate (27), oleana-9(11),12-dien-3-yl acetate (28), ursa-9(11),12-dien-3-yl decanoate (29), oleana-9(11),12-dien-3-yl decanoate (30), 12,13-epoxyolean-3-yl acetate (31), 12,13-epoxyolean-9(11)en-3-yl acetate (32), taraxeryl acetate (33), lupenyl acetate (34), lanosta-8,24-dien-3-yl acetate (35) and psoralen (36). The identification of the triterpene compounds isolated as isomeric mixtures obtained from the hexane extract was based mainly in mass spectra and 13C-NMR data. The long-chain alkanoic acid esters of the triterpenes α- and β-amyrin; 11-oxo-α- and 11-oxo-β-amyrin; ursa- and olean-9(11),12-dien-3-yl; have not been reported before in the literature as constituents of the Dorstenia genus. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids)
Open AccessArticle Two New Monoterpene Glycosides from Qing Shan Lu Shui Tea with Inhibitory Effects on Leukocyte-Type 12-Lipoxygenase Activity
Molecules 2013, 18(4), 4257-4266; doi:10.3390/molecules18044257
Received: 18 February 2013 / Revised: 7 April 2013 / Accepted: 8 April 2013 / Published: 11 April 2013
Cited by 1 | PDF Full-text (397 KB) | HTML Full-text | XML Full-text
Abstract
We evaluated the inhibitory effect of 12 Chinese teas on leukocyte-type 12-lipoxygenase (LOX) activity. Tea catechins such as epigallocatechin gallate have been known to exhibit leukocyte-type 12-LOX inhibition. Qing Shan Lu Shui, which contains lower catechin levels than the other tested teas, suppressed
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We evaluated the inhibitory effect of 12 Chinese teas on leukocyte-type 12-lipoxygenase (LOX) activity. Tea catechins such as epigallocatechin gallate have been known to exhibit leukocyte-type 12-LOX inhibition. Qing Shan Lu Shui, which contains lower catechin levels than the other tested teas, suppressed leukocyte-type 12-LOX activity. To characterize the bioactive components of Qing Shan Lu Shui, leukocyte-type 12-LOX inhibitory activity–guided fractionation of the aqueous ethanol extract of the tea was performed, resulting in the isolation of two new monoterpene glycosides: liguroside A (1) and B (2). The structures of compounds 1 and 2 were characterized as (2E,5E)-7-hydroperoxy-3,7-dimethyl-2,5-octadienyl-O-(α-L-rhamnopyranosyl)-(1″→3′)-(4′″-O-trans-p-coumaroyl)-β-D-glucopyranoside and (2E,5E)-7-hydroperoxy-3,7-dimethyl-2,5-octa-dienyl- O-(α-L-rhamnopyranosyl)-(1″→3′)-(4′″-O-cis-p-coumaroyl)-β-D-glucopyranoside, respectively, based on spectral and chemical evidence. Ligurosides A (1) and B (2) showed inhibitory effects on leukocyte-type 12-LOX activity, with IC50 values of 1.7 and 0.7 μM, respectively. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Metabolomic Analysis of Methyl Jasmonate-Induced Triterpenoid Production in the Medicinal Herb Centella asiatica (L.) Urban
Molecules 2013, 18(4), 4267-4281; doi:10.3390/molecules18044267
Received: 31 January 2013 / Revised: 3 April 2013 / Accepted: 3 April 2013 / Published: 11 April 2013
Cited by 12 | PDF Full-text (245 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Centella asiatica is an important source of biologically active pentacyclic triterpenoids. The enhancement of the biosynthesis of the centellosides by manipulation of associated metabolic pathways is receiving much attention. Jasmonates play critical roles in plant metabolism by up-regulating the expression of genes related
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Centella asiatica is an important source of biologically active pentacyclic triterpenoids. The enhancement of the biosynthesis of the centellosides by manipulation of associated metabolic pathways is receiving much attention. Jasmonates play critical roles in plant metabolism by up-regulating the expression of genes related to secondary metabolites. Here, we investigated the effect of methyl jasmonate (MeJa) in C. asiatica through targeted metabolomic profiling of asiaticoside and madecassoside as well as their aglycones, asiatic acid and madecassic acid. Cell suspensions were treated with 0.2 mM MeJa for 2, 4 and 6 days. Liquid chromatography coupled to mass spectrometry (LC-MS) was used to explore induced changes in metabolite profiles, both qualitatively and quantitatively. Principal component analysis (PCA)-derived scores plots revealed clusters of sample replicates for control and treated samples at 2, 4 and 6 days while loading plots aided in identifying signatory biomarkers (asiatic acid and madecassic acid, as well as asiaticoside and madecassoside) that clearly demonstrate the variability between samples. In addition to increased biosynthesis of the targeted centelloids, other differential changes in the intracellular metabolite profiles reflected the response of the C. asiatica cells to the MeJa-treatment as a reprogramming of the metabolome. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids)
Open AccessArticle Antioxidant Activity and Proanthocyanidin Profile of Selliguea feei Rhizomes
Molecules 2013, 18(4), 4282-4292; doi:10.3390/molecules18044282
Received: 20 March 2013 / Revised: 4 April 2013 / Accepted: 8 April 2013 / Published: 11 April 2013
Cited by 6 | PDF Full-text (339 KB) | HTML Full-text | XML Full-text
Abstract
Proanthocyanidins from the rhizomes of Selliguea feei (PSFs) were solvent-extracted and fractionated by Sephadex LH-20 column chromatography to give a 2.42% isolated yield (dry matter basis). 1H-NMR spectroscopy revealed the mean degree of polymerization (mDP) to be 2.6. 13C-NMR analysis showed
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Proanthocyanidins from the rhizomes of Selliguea feei (PSFs) were solvent-extracted and fractionated by Sephadex LH-20 column chromatography to give a 2.42% isolated yield (dry matter basis). 1H-NMR spectroscopy revealed the mean degree of polymerization (mDP) to be 2.6. 13C-NMR analysis showed typical signals for afzelechin/epiafzelechin units. Clear peaks at 76 ppm and 84 ppm indicated that both stereoisomers (afzelechin/epiafzelechin) are present. In agreement with the NMR spectra, the ESI-MS spectrum indicated that PSFs are mainly monomers to trimers consisting of afzelechin/epiafzelechin units with A-type and B-type interflavanyl linkages. A trimer was purified and identified as demethylated selligueain B. Thiolysis confirmed the structure and the thiolytic products, methyl 2-[(2R, 3R, 4S)-3,5,7-trihydroxy-2-(4-hydroxyphenyl)chroman-4-yl]acetate (1) and 4β-(carboxymethyl)sulphanylepiafzelechin-(2β→O→7,4β→8)-epiafzelechin methyl ester (2), were purified and characterized. Selligueain A, demethylated selligueain B, compounds 1 and 2 possess high antioxidant capacity at 1.18 × 104, 1.16 × 104, 0.95 × 104 and 1.29 × 104 µmol TE/g, respectively. Full article
Open AccessCommunication Manganese(III) Acetate-mediated Oxidative Cyclization of a-Methylstyrene and trans-Stilbene with b-Ketosulfones
Molecules 2013, 18(4), 4293-4307; doi:10.3390/molecules18044293
Received: 27 February 2013 / Revised: 3 April 2013 / Accepted: 4 April 2013 / Published: 11 April 2013
Cited by 10 | PDF Full-text (369 KB) | HTML Full-text | XML Full-text
Abstract
A convenient microwave irradiation protocol was utilized for the synthesis of b-ketosulfones 15 in good yields. These sulfones reacted with alkenes through a radical oxidative cyclization mediated by Mn(OAc)3. Dihydrofurans 610 were obtained in moderate to good
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A convenient microwave irradiation protocol was utilized for the synthesis of b-ketosulfones 15 in good yields. These sulfones reacted with alkenes through a radical oxidative cyclization mediated by Mn(OAc)3. Dihydrofurans 610 were obtained in moderate to good yields starting from 1,1-disubstituted alkenes. Dihydrofurans 1115 were synthesized in moderate yields and unexpected cyclopropanes 1619 were obtained in low yields starting from 1,2-disubstituted alkenes. This protocol offers access to various dihydrofurans which could be tested for their antiparasitic potential. Full article
(This article belongs to the Section Organic Synthesis)
Open AccessArticle Chemical Composition, Antifungal and Insecticidal Activities of Hedychium Essential Oils
Molecules 2013, 18(4), 4308-4327; doi:10.3390/molecules18044308
Received: 17 February 2013 / Revised: 29 March 2013 / Accepted: 29 March 2013 / Published: 11 April 2013
Cited by 13 | PDF Full-text (173 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The antimicrobial properties of essential oils have been documented, and their use as “biocides” is gaining popularity. The aims of this study were to analyze the chemical composition and assess the biological activities of Hedychium essential oils. Oils from 19 Hedychium species and
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The antimicrobial properties of essential oils have been documented, and their use as “biocides” is gaining popularity. The aims of this study were to analyze the chemical composition and assess the biological activities of Hedychium essential oils. Oils from 19 Hedychium species and cultivars were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques. The antifungal and insecticidal activities of these oils were tested against Colletotrichum acutatum, C. fragariae, and C. gloeosporioides, and three insects, the azalea lace bug (Stephanitis pyrioides), the yellow fever mosquito (Aedes aegypti), and the red imported fire ant (Solenopsis invicta). Hedychium oils were rich in monoterpenes and sesquiterpenes, especially 1,8-cineole (0.1%–42%), linalool (<0.1%–56%), a-pinene (3%–17%), b-pinene (4%–31%), and (E)-nerolidol (0.1%–20%). Hedychium oils had no antifungal effect on C. gloeosporioides, C. fragariae, and C. acutatum, but most Hedychium oils effectively killed azalea lace bugs. The oils also show promise as an adult mosquito repellent, but they would make rather poor larvicides or adulticides for mosquito control. Hedychium oils acted either as a fire ant repellent or attractant, depending on plant genotype and oil concentration. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Evaluation of the Interaction between Long Telomeric DNA and Macrocyclic Hexaoxazole (6OTD) Dimer of a G-quadruplex Ligand
Molecules 2013, 18(4), 4328-4341; doi:10.3390/molecules18044328
Received: 12 March 2013 / Revised: 2 April 2013 / Accepted: 9 April 2013 / Published: 12 April 2013
Cited by 11 | PDF Full-text (504 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Macrocyclic hexaoxazole dimer of L2H2-6OTD-dimer (3) was newly synthesized as a telomeric G-quadruplex (G4) ligand, and interaction with long telomeric DNAs telo48, 72, and 96 was evaluated by means of electrophoresis mobility shift assay, CD spectra analysis, and CD melting experiments.
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Macrocyclic hexaoxazole dimer of L2H2-6OTD-dimer (3) was newly synthesized as a telomeric G-quadruplex (G4) ligand, and interaction with long telomeric DNAs telo48, 72, and 96 was evaluated by means of electrophoresis mobility shift assay, CD spectra analysis, and CD melting experiments. The L2H2-6OTD-dimer (3) interacted with the long telomeric DNAs by inducing anti-parallel type G4 structure of each unit of 24 bases, i.e., (TTAGGG)4 sequences. Dimer 3 stabilizes long telomeric DNAs more efficiently than the corresponding monomer of L2H2-6OTD (2). It showed potent inhibitory activity against telomerase, with an IC50 value of 7.5 nm. Full article
(This article belongs to the Special Issue Macrocyclic Chemistry)
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Open AccessArticle Anxiolytic Effects of Herbal Ethanol Extract from Gynostemma pentaphyllum in Mice after Exposure to Chronic Stress
Molecules 2013, 18(4), 4342-4356; doi:10.3390/molecules18044342
Received: 21 February 2013 / Revised: 7 April 2013 / Accepted: 8 April 2013 / Published: 12 April 2013
Cited by 11 | PDF Full-text (231 KB) | HTML Full-text | XML Full-text
Abstract
In this study, the effects of herbal ethanol extracts of Gynostemma pentaphyllum (GP-EX), on chronic electric footshock (EF) stress-induced anxiety disorders were investigated in mice, which were orally treated with GP-EX (30 mg/kg and 50 mg/kg) once a day for 14 days, followed
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In this study, the effects of herbal ethanol extracts of Gynostemma pentaphyllum (GP-EX), on chronic electric footshock (EF) stress-induced anxiety disorders were investigated in mice, which were orally treated with GP-EX (30 mg/kg and 50 mg/kg) once a day for 14 days, followed by exposure to EF stress (2 mA, with an interval and duration of 10 s for 3 min). After the final exposure to EF stress, the elevated plus-maze and marble burying tests were performed, and the levels of dopamine and serotonin in the brain, the serum levels of corticosterone, and the expression of c-Fos in the paraventricular nuclei (PVN) were determined. Treatment with GP-EX (30 mg/kg and 50 mg/kg) significantly recovered the number of entries into open arms and time spent on open arms, which was reduced by chronic EF stress. GP-EX (30 mg/kg and 50 mg/kg) also reduced the number of marbles buried, which was increased by chronic EF stress. In addition, electric EF stress significantly decreased the levels of dopamine and serotonin in the brain, which was recovered by treatment with GP-EX (30 mg/kg and 50 mg/kg). The serum levels of corticosterone, which were markedly increased by chronic EF stress, were reduced by treatment with GP-EX (30 mg/kg and 50 mg/kg). Chronic EF stress-induced increases in c-Fos expression were also markedly reduced by GP-EX (30 mg/kg and 50 mg/kg) in the PVN. These results suggest that GP-EX shows anxiolytic functions, determined by the elevated plus-maze and marble burying tests, which are mediated by modulating the activity of dopamine and serotonin neurons as well as the expression of c-Fos in the brain, and the serum levels of corticosterone. Clinical trials of herbal GP-EX and its bioactive components need further investigation. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Application Scope and Limitations of TADDOL-Derived Chiral Ammonium Salt Phase-Transfer Catalysts
Molecules 2013, 18(4), 4357-4372; doi:10.3390/molecules18044357
Received: 25 March 2013 / Revised: 8 April 2013 / Accepted: 11 April 2013 / Published: 12 April 2013
Cited by 6 | PDF Full-text (448 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We have recently introduced a new class of chiral ammonium salt catalysts derived from easily available TADDOLs. To get a full picture of the scope of application and limitations of our catalysts we tested them in a variety of different important transformations. We
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We have recently introduced a new class of chiral ammonium salt catalysts derived from easily available TADDOLs. To get a full picture of the scope of application and limitations of our catalysts we tested them in a variety of different important transformations. We found that, although these compounds have recently shown their good potential in the asymmetric α-alkylation of glycine Schiff bases, they clearly failed when we attempted to control more reactive nucleophiles like b-keto esters. On the other hand, when using them to catalyse the addition of glycine Schiff bases to different Michael acceptors it was found necessary to carefully optimize the reaction conditions for every single substrate class, as seemingly small structural changes sometimes required the use of totally different reaction conditions. Under carefully optimized conditions enantiomeric ratios up to 91:9 could be achieved in the addition of glycine Schiff bases to acrylates, whereas acrylamides and methyl vinyl ketone gave slightly lower selectivities (up to e.r. 77:23 in these cases). Thus, together with additional studies towards the syntheses of these catalysts we have now a very detailed understanding about the scope and limitations of the synthesis sequence to access our PTCs and about the application scope of these catalysts in asymmetric transformations. Full article
(This article belongs to the Special Issue Asymmetric Catalysis)
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Open AccessArticle Preparation, Purification and Regioselective Functionalization of Protoescigenin—The Main Aglycone of Escin Complex
Molecules 2013, 18(4), 4389-4402; doi:10.3390/molecules18044389
Received: 8 February 2013 / Revised: 1 April 2013 / Accepted: 9 April 2013 / Published: 15 April 2013
Cited by 7 | PDF Full-text (984 KB) | HTML Full-text | XML Full-text
Abstract
A two-step chemical process for controlled degradation of escin, affording a mixture of olean-12-ene sapogenins, was elaborated and scaled up. The main component of the mixture—protoescigenin—was isolated and purified, in the form of its corresponding monohydrate, without resource to chromatographic methods. This material
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A two-step chemical process for controlled degradation of escin, affording a mixture of olean-12-ene sapogenins, was elaborated and scaled up. The main component of the mixture—protoescigenin—was isolated and purified, in the form of its corresponding monohydrate, without resource to chromatographic methods. This material was further converted into the high purity 3,24;16,22-di-O,O-isopropylidene derivative in a validated large scale laboratory process. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids)
Open AccessArticle Palladium(II)-Catalyzed othro-C–H-Benzoxylation of 2-Arylpyridines by Oxidative Coupling with Aryl Acylperoxides
Molecules 2013, 18(4), 4403-4418; doi:10.3390/molecules18044403
Received: 5 March 2013 / Revised: 21 March 2013 / Accepted: 21 March 2013 / Published: 15 April 2013
Cited by 12 | PDF Full-text (254 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract A palladium(II)-catalyzed ortho-benzoxylation of 2-arylpyridines with aryl acylperoxides was developed. With pyridyl as directing group, the benzoxylation reaction exhibits remarkable regioselectivity and excellent functional group tolerance, providing the products in up to 87% yield. Full article
Open AccessArticle Evaluation of the Biological Activity of Naturally Occurring 5,8-Dihydroxycoumarin
Molecules 2013, 18(4), 4419-4436; doi:10.3390/molecules18044419
Received: 19 February 2013 / Revised: 21 March 2013 / Accepted: 9 April 2013 / Published: 15 April 2013
Cited by 4 | PDF Full-text (468 KB) | HTML Full-text | XML Full-text
Abstract
5,8-Dihydroxycoumarin (5,8-DHC) was isolated from aerial parts of sweet grass (Hierochloë odorata L.) and screened for antioxidant and genotoxic activities. A clear linear dependency of radical scavenging capacity in DPPH and ABTS•+ assays was determined. 5,8-DHC was very efficient in
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5,8-Dihydroxycoumarin (5,8-DHC) was isolated from aerial parts of sweet grass (Hierochloë odorata L.) and screened for antioxidant and genotoxic activities. A clear linear dependency of radical scavenging capacity in DPPH and ABTS•+ assays was determined. 5,8-DHC was very efficient in retarding rapeseed oil oxidation (Oxipress test). TPC (total phenols content) and FRAP (the ability to reduce ferric ion to ferrous ion) assays revealed a somewhat lower antioxidant capacity of 5,8-DHC as compared with gallic acid. Genotoxic activity was tested using different genetic end-points: chromosome aberrations (CAs) and micronuclei (MN) in Wistar rat bone marrow in vivo, CAs and sister chromatid exchanges (SCEs) in human lymphocytes in vitro, and somatic mutations and recombination in Drosophila melanogaster wing cells in vivo. 5,8-DHC did not increase frequency of CAs in rat bone marrow cells, but induced a significant increase of MN. It was slightly mutagenic in the Drosophila melanogaster assay after 120 h of treatment, but not after 48 h of treatment. 5,8-DHC induced both CAs and SCEs in vitro in human lymphocytes in a clear dose-dependent manner. Thus, 5,8-DHC may be classified as weakly genotoxic both in vivo and in vitro. Full article
(This article belongs to the Special Issue Phytochemicals: Analytical and Medicinal Chemistry)
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Open AccessArticle Hydrophobic Effect of Amphiphilic Derivatives of Chitosan on the Antifungal Activity against Aspergillus flavus and Aspergillus parasiticus
Molecules 2013, 18(4), 4437-4450; doi:10.3390/molecules18044437
Received: 19 February 2013 / Revised: 20 March 2013 / Accepted: 9 April 2013 / Published: 15 April 2013
Cited by 5 | PDF Full-text (528 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Low molecular weight amphiphilic derivatives of chitosan were synthesized, characterized and their antifungal activities against Aspergillus flavus and Aspergillus parasiticus were tested. The derivatives were synthesized using as starting material a deacetylated chitosan sample in a two step process: the reaction with propyltrimethyl-ammonium
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Low molecular weight amphiphilic derivatives of chitosan were synthesized, characterized and their antifungal activities against Aspergillus flavus and Aspergillus parasiticus were tested. The derivatives were synthesized using as starting material a deacetylated chitosan sample in a two step process: the reaction with propyltrimethyl-ammonium bromide (Pr), followed by reductive amination with dodecyl aldehyde. Aiming to evaluate the effect of the hydrophobic modification of the derivatives on the antifungal activity against the pathogens, the degree of substitution (DS1) by Pr groups was kept constant and the proportion of dodecyl (Dod) groups was varied from 7 to 29% (DS2). The derivatives were characterized by 1H-NMR and FTIR and their antifungal activities against the pathogens were tested by the radial growth of the colony and minimum inhibitory concentration (MIC) methods. The derivatives substituted with only Pr groups exhibited modest inhibition against A. flavus and A. parasiticus, like that obtained with deacetylated chitosan. Results revealed that the amphiphilic derivatives grafted with Dod groups exhibited increasing inhibition indexes, depending on polymer concentration and hydrophobic content. At 0.6 g/L, all amphiphilic derivatives having from 7.0 to 29% of Dod groups completely inhibited fungal growth and the MIC values were found to decrease from 4.0 g/L for deacetylated chitosan to 0.25–0.50 g/L for the derivatives. These new derivatives open up the possibility of new applications and avenues to develop effective biofungicides based on chitosan. Full article
(This article belongs to the Special Issue Chitins and Chitosans)
Open AccessArticle Phosphorus Dendrimers as Carriers of siRNA—Characterisation of Dendriplexes
Molecules 2013, 18(4), 4451-4466; doi:10.3390/molecules18044451
Received: 18 March 2013 / Revised: 3 April 2013 / Accepted: 11 April 2013 / Published: 15 April 2013
Cited by 11 | PDF Full-text (545 KB) | HTML Full-text | XML Full-text
Abstract
There are many types of dendrimers used as nanomolecules for gene delivery but there is still an ongoing search for ones that are able to effectively deliver drugs to cells. The possibility of gene silencing using siRNA gives hope for effective treatment of
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There are many types of dendrimers used as nanomolecules for gene delivery but there is still an ongoing search for ones that are able to effectively deliver drugs to cells. The possibility of gene silencing using siRNA gives hope for effective treatment of numerous diseases. The aim of this work was to investigate in vitro biophysical properties of dendriplexes formed by siRNA and cationic phosphorus dendrimers of 3rd and 4th generation. First, using the ethidium bromide intercalation method, it was examined whether dendrimers have an ability to form complexes with siRNA. Next, the characterisation of dendriplexes formed at different molar ratios was carried out using biophysical methods. The effects of zeta potential, size and changes of siRNA conformation on the complexation with dendrimers were examined. It was found that both phosphorus dendrimers interacted with siRNA. The zeta potential values of dendriplexes ranged from negative to positive and the hydrodynamic diameter depended on the number of dendrimer molecules in the complex. Furthermore, using circular dichroism spectroscopy it was found that cationic phosphorus dendrimers changed only slightly the shape of siRNA CD spectra, thus they did not induce significant changes in the nucleic acid secondary structure during complex formation. Full article
(This article belongs to the Special Issue Dendrimers in Medicine and Biotechnology)
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Open AccessArticle Chemical Constituents from the Leaves of Annona reticulata and Their Inhibitory Effects on NO Production
Molecules 2013, 18(4), 4477-4486; doi:10.3390/molecules18044477
Received: 24 January 2013 / Revised: 3 April 2013 / Accepted: 12 April 2013 / Published: 16 April 2013
Cited by 6 | PDF Full-text (231 KB) | HTML Full-text | XML Full-text
Abstract
In the present study, the chemical investigation of the leaves of Annona reticulata has resulted in the identification of nine compounds, including annonaretin A, (1), a new triterpenoid. The purified compounds were subjected to the examination of their effects on NO
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In the present study, the chemical investigation of the leaves of Annona reticulata has resulted in the identification of nine compounds, including annonaretin A, (1), a new triterpenoid. The purified compounds were subjected to the examination of their effects on NO inhibition in LPS-activated mouse peritoneal macrophages and most of them exhibited significant NO inhibition, with IC50 values in the range of 48.6 ± 1.2 and 99.8 ± 0.4 μM. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Synthesis and Biological Evaluation of Thieno[3,2-d]- pyrimidinones, Thieno[3,2-d]pyrimidines and Quinazolinones: Conformationally Restricted 17b-Hydroxysteroid Dehydrogenase Type 2 (17b-HSD2) Inhibitors
Molecules 2013, 18(4), 4487-4509; doi:10.3390/molecules18044487
Received: 22 March 2013 / Revised: 8 April 2013 / Accepted: 10 April 2013 / Published: 16 April 2013
Cited by 2 | PDF Full-text (418 KB) | HTML Full-text | XML Full-text
Abstract
In this study, a series of conformationally restricted thieno[3,2-d]pyrimidinones, thieno[3,2-d]pyrimidines and quinazolinones was designed and synthesized with the goal of improving the biological activity as 17b-hydroxysteroid dehydrogenase type 2 inhibitors of the corresponding amidothiophene derivatives. Two moderately active compounds
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In this study, a series of conformationally restricted thieno[3,2-d]pyrimidinones, thieno[3,2-d]pyrimidines and quinazolinones was designed and synthesized with the goal of improving the biological activity as 17b-hydroxysteroid dehydrogenase type 2 inhibitors of the corresponding amidothiophene derivatives. Two moderately active compounds were discovered and this allowed the identification of the biologically active open conformer as well as the extension of the enzyme binding site characterisation. Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessArticle The Use of Bio-Guided Fractionation to Explore the Use of Leftover Biomass in Dutch Flower Bulb Production as Allelochemicals against Weeds
Molecules 2013, 18(4), 4510-4525; doi:10.3390/molecules18044510
Received: 28 February 2013 / Revised: 28 March 2013 / Accepted: 12 April 2013 / Published: 17 April 2013
PDF Full-text (649 KB) | HTML Full-text | XML Full-text
Abstract
A major problem in flower bulb cultivation is weed control. Synthetic herbicides are mainly used, although they cause a range of problems, and integrated weed control through application of naturally occurring allelochemicals would be highly desirable. Flower bulb production creates large amounts of
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A major problem in flower bulb cultivation is weed control. Synthetic herbicides are mainly used, although they cause a range of problems, and integrated weed control through application of naturally occurring allelochemicals would be highly desirable. Flower bulb production creates large amounts of leftover biomass. Utilizing this source for weed control may provide new applications of the bulb crops. We therefore screened 33 flower bulb extracts for allelochemical activity against weeds. Several methanol and chloroform extracts were observed to inhibit germination and growth of Senecio vulgaris L. and Lolium perenne L., as representatives of di- and mono-cotyledonous weeds, respectively. Narciclasine was identified as the bioactive compound in Narcissus. The extract of Amaryllis belladonna L. was equally active, but did not contain any narciclasine. Bioassay-guided fractionation of the A. belladonna extract resulted in the identification of lycorine as the bio-active compound. The IC50 measured for radicle growth inhibition was 0.10 µM for narciclasine and 0.93 µM for lycorine, compared to 0.11 mM of chlorpropham, a synthetic herbicide. Therefore, the leftover biomass from the spring bulb industry represents an interesting potential source for promising allelochemicals for further studies on weed growth inhibition. Full article
(This article belongs to the Special Issue Bioassay-Guided Isolation of Natural Products)
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Open AccessArticle Synthesis, Structure and Cytotoxic Activity of New Acetylenic Derivatives of Betulin
Molecules 2013, 18(4), 4526-4543; doi:10.3390/molecules18044526
Received: 21 March 2013 / Revised: 8 April 2013 / Accepted: 11 April 2013 / Published: 17 April 2013
Cited by 13 | PDF Full-text (393 KB) | HTML Full-text | XML Full-text
Abstract
A new series of betulin derivatives containing one or two pharmacophores bearing an acetylenic and carbonyl function at the C-3 and/or C-28 positions has been synthesized and characterized by 1H- and 13C-NMR, IR, MS and elemental analyses. The crystal structure of
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A new series of betulin derivatives containing one or two pharmacophores bearing an acetylenic and carbonyl function at the C-3 and/or C-28 positions has been synthesized and characterized by 1H- and 13C-NMR, IR, MS and elemental analyses. The crystal structure of 28-O-propynoylbetulin was determined by X-ray structural analysis. All new compounds, as well as betulin, were tested in vitro for their antiproliferative activity against human SW707 colorectal, CCRF/CEM leukemia, T47D breast cancer, and against murine P388 leukemia and Balb3T3 normal fibroblasts cell lines. Most of the compounds showed better cytotoxicity than betulin and cisplatin used as reference agent. 28-O-Propynoylbetulin was the most potent derivative, being over 500 times more potent than betulin and about 100 times more cytotoxic than cisplatin against the human leukemia (CCRF/CEM) cell line, with an ID50 value of 0.02 μg/mL. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessArticle Deuterium Isotope Effects on 13C-NMR Chemical Shifts of 10-Hydroxybenzo[h]quinolines
Molecules 2013, 18(4), 4544-4560; doi:10.3390/molecules18044544
Received: 1 March 2013 / Revised: 9 April 2013 / Accepted: 15 April 2013 / Published: 17 April 2013
Cited by 6 | PDF Full-text (304 KB) | HTML Full-text | XML Full-text
Abstract
Deuterium isotope effects on 13C-NMR chemical shifts are investigated in a series of 10-hydroxybenzo[h]quinolines (HBQ’s) The OH proton is deuteriated. The isotope effects on 13C chemical shifts in these hydrogen bonded systems are rather unusual. The formal four-bond effects
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Deuterium isotope effects on 13C-NMR chemical shifts are investigated in a series of 10-hydroxybenzo[h]quinolines (HBQ’s) The OH proton is deuteriated. The isotope effects on 13C chemical shifts in these hydrogen bonded systems are rather unusual. The formal four-bond effects are found to be negative, indicating transmission via the hydrogen bond. In addition unusual long-range effects are seen. Structures, NMR chemical shifts and changes in nuclear shieldings upon deuteriation are calculated using DFT methods. Two-bond deuterium isotope effects on 13C chemical shifts are correlated with calculated OH stretching frequencies. Isotope effects on chemical shifts are calculated for systems with OH exchanged by OD. Hydrogen bond potentials are discussed. New and more soluble nitro derivatives are synthesized. Full article
(This article belongs to the Special Issue Isotope Effects)
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Open AccessArticle Synthesis, Biological Evaluation, and Pharmacokinetic Study of Novel Liguzinediol Prodrugs
Molecules 2013, 18(4), 4561-4572; doi:10.3390/molecules18044561
Received: 15 March 2013 / Revised: 8 April 2013 / Accepted: 11 April 2013 / Published: 18 April 2013
Cited by 4 | PDF Full-text (275 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Liguzinediol (LZDO) ester prodrugs 35 were synthesized and evaluated in vitro and in vivo for their potential use in prolonging the half-life of the parent drug LZDO (1a) in vivo. Prodrugs 35 were found to display
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Liguzinediol (LZDO) ester prodrugs 35 were synthesized and evaluated in vitro and in vivo for their potential use in prolonging the half-life of the parent drug LZDO (1a) in vivo. Prodrugs 35 were found to display a potent positive inotropic effect on the myocardium, without the risk of arrhythmia. Prodrugs 35 rapidly underwent enzymatic hydrolysis to release the parent compound LZDO in 1–3 h in rat liver microsomes and rat plasma. The half-life of the parent compound was prolonged after intragastric administration of prodrug 3, which was found to be a superior prodrug candidate for increasing myocardial contractility. Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessArticle Triacylglyceride, Antioxidant and Antimicrobial Features of Virgin Camellia oleifera, C. reticulata and C. sasanqua Oils
Molecules 2013, 18(4), 4573-4587; doi:10.3390/molecules18044573
Received: 13 March 2013 / Revised: 9 April 2013 / Accepted: 15 April 2013 / Published: 18 April 2013
Cited by 6 | PDF Full-text (317 KB) | HTML Full-text | XML Full-text
Abstract
Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata (CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition, antioxidant and antimicrobial activities. Levels of fatty acids determined by 1H-nuclear magnetic resonance analysis were similar to those reported for
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Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata (CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition, antioxidant and antimicrobial activities. Levels of fatty acids determined by 1H-nuclear magnetic resonance analysis were similar to those reported for olive oils (82.30%–84.47%; 5.69%–7.78%; 0.26%–0.41% and 8.04%–11.2%, for oleic, linoleic, linolenic and saturated acids, respectively). The CR oil showed the best antioxidant potential in the three in vitro models tested. With regard to EC50 values (µg/mL), the order in DPPH radical-scavenging was CR (33.48) < CO (35.20) < CS (54.87). Effectiveness in reducing power was CR (2.81) < CO (3.09) < CS (5.32). IC50 for LPO inhibition were 0.37, 0.52 and 0.75 µg/mL for CR, CO and CS, respectively. All the oils showed antimicrobial activity, and exhibited different selectivity and MICs for each microorganism tested (E. coli, B. cereus and C. albicans). B. cereus was the less sensitive species (MIC: 52.083 ± 18.042 for CO; 41.667 ± 18.042 for CR; 104.167 ± 36.084 for CS mg/mL) and the E. coli was the most sensitive to camellia oil’s effect. The standard gentamicin presented higher MIC for E. coli (4.2) than the CR (MIC= 2.6) and CO (MIC = 3.9) oils. Full article
Open AccessArticle Chemical Composition, Cytotoxic and Antimicrobial Activity of Essential Oils from Cassia bakeriana Craib. against Aerobic and Anaerobic Oral Pathogens
Molecules 2013, 18(4), 4588-4598; doi:10.3390/molecules18044588
Received: 21 March 2013 / Revised: 16 April 2013 / Accepted: 16 April 2013 / Published: 18 April 2013
Cited by 5 | PDF Full-text (217 KB) | HTML Full-text | XML Full-text
Abstract
The chemical composition of the essential oils from leaves, bark and wood of Cassia bakeriana Craib. was determined by gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). Alcohols, aldehydes and fatty acids were the major components in leaf and bark oil, while wood
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The chemical composition of the essential oils from leaves, bark and wood of Cassia bakeriana Craib. was determined by gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). Alcohols, aldehydes and fatty acids were the major components in leaf and bark oil, while wood essential oil was rich in fatty acids. Terpenes such as linalool, (E)-nerolidol and phytol were present in low concentrations. The antimicrobial activity against aerobic and anaerobic oral bacteria was evaluated using the microdilution method, as was the cell viability test carried out with Vero cells. The oils from leaves and bark showed high antimicrobial activity, with minimum inhibitory concentrations between 62.5 and 125 µg·mL−1 for most of the tested bacteria, including Streptococcus mutans, the main etiological agent of dental caries. Leaves oil displayed the lowest cytotoxic effect (EC50 of 153 µg·mL−1), while wood oil exhibited the highest toxicity to Vero cells. C. bakeriana oils are thus a source of biologically active compounds against aerobic and anaerobic oral microorganisms. This study is the first report on the chemical composition, antimicrobial activity and cytotoxicity of C. bakeriana. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Functionalization of Multi-Walled Carbon Nanotubes with Thermo-Responsive Azide-Terminated Poly(N-isopropylacrylamide) via Click Reactions
Molecules 2013, 18(4), 4599-4612; doi:10.3390/molecules18044599
Received: 24 January 2013 / Revised: 10 April 2013 / Accepted: 15 April 2013 / Published: 18 April 2013
Cited by 6 | PDF Full-text (404 KB) | HTML Full-text | XML Full-text
Abstract
Covalently functionalized multi-walled carbon nanotubes (MWNTs) were prepared by grafting well-defined thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) via click reactions. First, azide-terminated poly(N-isopropylacrylamide) (N3-PNIPAM) was synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization, and then the N3-PNIPAM moiety
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Covalently functionalized multi-walled carbon nanotubes (MWNTs) were prepared by grafting well-defined thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) via click reactions. First, azide-terminated poly(N-isopropylacrylamide) (N3-PNIPAM) was synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization, and then the N3-PNIPAM moiety was connected onto MWNTs by click chemistry. The products were characterized by means of FT-IR, TGA and TEM. The results show that the modification of MWNTs is very successful and MWNTs functionalized by N3-PNIPAM (MWNTs-PNIPAM) have good solubility and stability in water. TEM images show the functionalized MWNTs are dispersed individually, indicating that the bundles of original MWNTs are separated into individual tubes by surface modification with polymer chains. These MWNTs modified with PNIPAM represent a potential nano-material for preparation of hydrophilic composite materials. Full article
Open AccessArticle Synthesis of New 1,2,3-Triazole Derivatives of Uracil and Thymine with Potential Inhibitory Activity against Acidic Corrosion of Steels
Molecules 2013, 18(4), 4613-4627; doi:10.3390/molecules18044613
Received: 26 January 2013 / Revised: 11 April 2013 / Accepted: 16 April 2013 / Published: 18 April 2013
Cited by 12 | PDF Full-text (298 KB) | HTML Full-text | XML Full-text
Abstract
Ten 1,4-disubstituted 1,2,3-triazoles were synthesized from one of 1-(azido-methyl)benzene, 1-(azidomethyl)-4-fluorobenzene, 1-(azidomethyl)-4-chlorobenzene, 1-(azidomethyl)-4-bromobenzene or 1-(azidomethyl)-4-iodobenzene, generated in situ from sodium azide and the corresponding benzyl halide, and dipropargyl uracil or dipropargyl thymine. Optimal experimental conditions were established for the conventional click chemistry. The corrosion
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Ten 1,4-disubstituted 1,2,3-triazoles were synthesized from one of 1-(azido-methyl)benzene, 1-(azidomethyl)-4-fluorobenzene, 1-(azidomethyl)-4-chlorobenzene, 1-(azidomethyl)-4-bromobenzene or 1-(azidomethyl)-4-iodobenzene, generated in situ from sodium azide and the corresponding benzyl halide, and dipropargyl uracil or dipropargyl thymine. Optimal experimental conditions were established for the conventional click chemistry. The corrosion inhibiting properties of some of these compounds, which were determined by means of an electrochemical technique, are also presented. Full article
(This article belongs to the Section Organic Synthesis)
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Open AccessCommunication A Series of Asymmetrical Phthalocyanines: Synthesis and Near Infrared Properties
Molecules 2013, 18(4), 4628-4639; doi:10.3390/molecules18044628
Received: 30 January 2013 / Revised: 7 April 2013 / Accepted: 8 April 2013 / Published: 19 April 2013
Cited by 3 | PDF Full-text (390 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We report here the preparation of asymmetrical phthalocyanine dimers 1a3a, which are endowed with novel charge transfer bands at 1,151–1,154 nm and strong NIR luminescences at 840–860 nm and 1,600–1,650 nm. Through H-bonding interaction, 1a3a are inclined to
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We report here the preparation of asymmetrical phthalocyanine dimers 1a3a, which are endowed with novel charge transfer bands at 1,151–1,154 nm and strong NIR luminescences at 840–860 nm and 1,600–1,650 nm. Through H-bonding interaction, 1a3a are inclined to self-assemble into hexrod nanotubes at the interface of CHCl3 and CH3OH. Our results provide further insights into the interaction in molecular dimers, and suggest that 1a3a have potential application in magnets and supramolecular architectures. Full article
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Open AccessCommunication Arabinoxylan Microspheres: Structural and Textural Characteristics
Molecules 2013, 18(4), 4640-4650; doi:10.3390/molecules18044640
Received: 8 February 2013 / Revised: 7 April 2013 / Accepted: 8 April 2013 / Published: 19 April 2013
Cited by 5 | PDF Full-text (586 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this research was to study the structural and textural characteristics of maize bran arabinoxylan (MBAX) microspheres. The laccase-induced cross-linking process was monitored by storage (G') and loss (G'') moduli changes in a 4% (w/v) MBAX solution. The G' and G''
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The aim of this research was to study the structural and textural characteristics of maize bran arabinoxylan (MBAX) microspheres. The laccase-induced cross-linking process was monitored by storage (G') and loss (G'') moduli changes in a 4% (w/v) MBAX solution. The G' and G'' values at the plateau region were 215 and 4 Pa, respectively. After gelation, the content of ferulic acid dimers decreased from 0.135 to 0.03 µg/mg MBAX, suggesting the formation of ferulated structures unreleased by mild alkaline hydrolysis. MBAX microspheres presented an average diameter of 531 µm and a swelling ratio value (q) of 18 g water/g MBAX. The structural parameters of MBAX microspheres were calculated from equilibrium swelling experiments, presenting an average mesh size of 52 nm. Microstructure and textural properties of dried MBAX microspheres were studied by scanning electron microscopy and nitrogen adsorption/desorption isotherms, respectively, showing a heterogeneous mesoporous and macroporous structure throughout the network. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Evaluation of Biological Value and Appraisal of Polyphenols and Glucosinolates from Organic Baby-Leaf Salads as Antioxidants and Antimicrobials against Important Human Pathogenic Bacteria
Molecules 2013, 18(4), 4651-4668; doi:10.3390/molecules18044651
Received: 14 March 2013 / Revised: 12 April 2013 / Accepted: 17 April 2013 / Published: 19 April 2013
Cited by 2 | PDF Full-text (340 KB) | HTML Full-text | XML Full-text
Abstract
The present investigation has been carried out to investigate the biological role of four different types of baby-leaf salads and to study their potential as natural sources of antioxidants and antimicrobials against several isolates from important human pathogenic bacteria. Four single types of
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The present investigation has been carried out to investigate the biological role of four different types of baby-leaf salads and to study their potential as natural sources of antioxidants and antimicrobials against several isolates from important human pathogenic bacteria. Four single types of salads (green lettuce, red lettuce, rucola and watercress) and two mixtures [(1) red lettuce+green lettuce; (2) green lettuce + red lettuce + watercress + rucola] were assayed. The HPLC analysis revealed interesting levels of polyphenols and glucosinolates. The results showed a significant variation (p < 0.05) of polyphenols and glucosinolates with plant material. Nine different types of polyphenols grouped in three major classes were found: gallic acid, chlorogenic acid, caffeic acid and dicaffeoyltartaric acid (phenolic acids); quercitin-3-O-rutinoside, quercitin-3-O-rhamnoside, luteolin-7-O-glucoside and isorhamnetin (flavonoids); and cyanidin-3-glucoside (anthocyanins). Only three different glucosinolates were found: glucoraphanin; gluconasturtiin and 4-methoxy-glucobrassicin. A positive correlation was detected between polyphenol contents and antioxidant activity. Red lettuce and mixture 1 were the baby-leaf salads with the highest antioxidant potential. As for the antimicrobial activity, the results showed a selective effect of chemicals against Gram-positive and Gram-negative bacteria and Enterococcus faecalis and Staphylococcus aureus were the bacteria most affected by the phytochemicals. Based on the results achieved baby-leaf salads represent an important source of natural antioxidants and antimicrobial substances. Full article
Open AccessArticle Synthesis and Antimicrobial Activity of Some New Thieno[2,3-b]thiophene Derivatives
Molecules 2013, 18(4), 4669-4678; doi:10.3390/molecules18044669
Received: 28 March 2013 / Revised: 10 April 2013 / Accepted: 16 April 2013 / Published: 19 April 2013
Cited by 7 | PDF Full-text (305 KB) | HTML Full-text | XML Full-text
Abstract
A series of thieno[2,3-b]thiophene moiety-containing bis-cyanopyrazoles 5ac, bis-aminopyrazole 9 and bis-pyridazine derivatives 11 were synthesized and evaluated in vitro for their antimicrobial potential. The antimicrobial activity of some selected products was evaluated and showed good
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A series of thieno[2,3-b]thiophene moiety-containing bis-cyanopyrazoles 5ac, bis-aminopyrazole 9 and bis-pyridazine derivatives 11 were synthesized and evaluated in vitro for their antimicrobial potential. The antimicrobial activity of some selected products was evaluated and showed good results. 5,5'-(3,4-Dimethylthieno[2,3-b]thiophene-2,5-diyl)bis(3-acetyl-1-(4-chlorophenyl)-1H-pyrazole-4-carbonitrile) (5d) was found to be more potent than the standard drug amphotericin B against Geotricum candidum and equipotent to amphotericin B against Syncephalastrum racemosum. In addition, it was found to be equipotent to the standard drug Penicillin G against Staphylococcus aureus. Moreover, it was more potent than the standard drug streptomycin against Pseudomonas aeruginosa and Escherichia coli. Full article
(This article belongs to the Section Organic Synthesis)
Open AccessArticle Microwave-Assisted Synthesis of New Selenazole Derivatives with Antiproliferative Activity
Molecules 2013, 18(4), 4679-4688; doi:10.3390/molecules18044679
Received: 11 March 2013 / Revised: 12 April 2013 / Accepted: 17 April 2013 / Published: 19 April 2013
Cited by 11 | PDF Full-text (212 KB) | HTML Full-text | XML Full-text
Abstract
New aryl-hydrazinyl-1,3-selenazole and aroyl-hydrazonyl-1,3-selenazoles were synthesized via Hantzsch type condensation reactions of selenosemicarbazides with α-halogenocarbonyl derivatives, under classical versus microwave heating conditions. Excellent yields and shorter reaction times were obtained under irradiation conditions. The structures of the synthesized compounds were assigned based on
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New aryl-hydrazinyl-1,3-selenazole and aroyl-hydrazonyl-1,3-selenazoles were synthesized via Hantzsch type condensation reactions of selenosemicarbazides with α-halogenocarbonyl derivatives, under classical versus microwave heating conditions. Excellent yields and shorter reaction times were obtained under irradiation conditions. The structures of the synthesized compounds were assigned based on spectroscopic data (FT-IR, 1H-NMR), MS and elemental analysis. Selenazole derivatives were screened for their anti-proliferative effects against two leukemia cell lines (CCRF-CEM and HL60) and three carcinoma cell lines (MDA-MB231, HCT116 and U87MG). Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessArticle Resveratrol Protects against Physical Fatigue and Improves Exercise Performance in Mice
Molecules 2013, 18(4), 4689-4702; doi:10.3390/molecules18044689
Received: 4 February 2013 / Revised: 17 April 2013 / Accepted: 18 April 2013 / Published: 19 April 2013
Cited by 28 | PDF Full-text (2944 KB) | HTML Full-text | XML Full-text
Abstract
Resveratrol (RES) is a well-known phytocompound and food component which has antioxidative and multifunctional bioactivities. However, there is limited evidence for the effects of RES on physical fatigue and exercise performance. The purpose of this study was to evaluate the potential beneficial effects
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Resveratrol (RES) is a well-known phytocompound and food component which has antioxidative and multifunctional bioactivities. However, there is limited evidence for the effects of RES on physical fatigue and exercise performance. The purpose of this study was to evaluate the potential beneficial effects of trans-RES on fatigue and ergogenic functions following physiological challenge. Male ICR mice from four groups (n = 8 per group) were orally administered RES for 21 days at 0, 25, 50, and 125 mg/kg/day, which were respectively designated the vehicle, RES-25, RES-50, and RES-125 groups. The anti-fatigue activity and exercise performance were evaluated using forelimb grip strength, exhaustive swimming time, and levels of serum lactate, ammonia, glucose, and creatine kinase (CK) after a 15-min swimming exercise. The exhaustive swimming time of the RES-25 group (24.72 ± 7.35 min) was significantly (p = 0.0179) longer than that of vehicle group (10.83 ± 1.15 min). A trend analysis revealed that RES treatments increased the grip strength. RES supplementation also produced dose-dependent decreases in serum lactate and ammonia levels and CK activity and also an increase in glucose levels in dose-dependent manners after the 15-min swimming test. The mechanism was related to the increased energy utilization (as blood glucose), and decreased serum levels of lactate, ammonia, and CK. Therefore, RES could be a potential agent with an anti-fatigue pharmacological effect. Full article
(This article belongs to the Section Natural Products)
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Open AccessArticle New Amide Derivatives of Quinoxaline 1,4-di-N-Oxide with Leishmanicidal and Antiplasmodial Activities
Molecules 2013, 18(4), 4718-4727; doi:10.3390/molecules18044718
Received: 26 March 2013 / Revised: 11 April 2013 / Accepted: 18 April 2013 / Published: 22 April 2013
Cited by 16 | PDF Full-text (192 KB) | HTML Full-text | XML Full-text
Abstract
Malaria and leishmaniasis are two of the World’s most important tropical parasitic diseases. Continuing with our efforts to identify new compounds active against malaria and leishmaniasis, twelve new 1,4-di-N-oxide quinoxaline derivatives were synthesized and evaluated for their in vitro antimalarial and
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Malaria and leishmaniasis are two of the World’s most important tropical parasitic diseases. Continuing with our efforts to identify new compounds active against malaria and leishmaniasis, twelve new 1,4-di-N-oxide quinoxaline derivatives were synthesized and evaluated for their in vitro antimalarial and antileishmanial activity against Plasmodium falciparum FCR-3 strain, Leishmania infantum and Leishmania amazonensis. Their toxicity against VERO cells (normal monkey kidney cells) was also assessed. The results obtained indicate that a cyclopentyl derivative had the best antiplasmodial activity (2.9 µM), while a cyclohexyl derivative (2.5 µM) showed the best activity against L. amazonensis, and a 3-chloropropyl derivative (0.7 µM) showed the best results against L. infantum. All these compounds also have a Cl substituent in the R7 position. Full article
Open AccessArticle A New Vanadium (III) Complex of 2,6-Bis(3,5-diphenylpyrazol-1-ylmethyl)pyridine as a Catalyst for Ethylene Polymerization
Molecules 2013, 18(4), 4728-4738; doi:10.3390/molecules18044728
Received: 11 March 2013 / Revised: 17 April 2013 / Accepted: 18 April 2013 / Published: 22 April 2013
Cited by 8 | PDF Full-text (326 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The tridentate ligand 2,6-bis(3,5-diphenylpyrazol-1-ylmethyl)pyridine, abbreviated as 2,6-[(3,5-ph2pz-CH2)2-py], a new pyridine-pyrazole derivative, was prepared from 2,6-bis(bromomethyl)pyridine and 3,5-diphenylpyrazole. The ligand was characterized by means of elemental analyses, ATR-IR, 1H- and 13C-NMR spectroscopy and single crystal X-ray
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The tridentate ligand 2,6-bis(3,5-diphenylpyrazol-1-ylmethyl)pyridine, abbreviated as 2,6-[(3,5-ph2pz-CH2)2-py], a new pyridine-pyrazole derivative, was prepared from 2,6-bis(bromomethyl)pyridine and 3,5-diphenylpyrazole. The ligand was characterized by means of elemental analyses, ATR-IR, 1H- and 13C-NMR spectroscopy and single crystal X-ray crystallography. Using this ligand, a new mononuclear vanadium (III) complex, {2,6-[(3,5-ph2pz)CH2]2py}VCl3 was prepared and characterized by elemental analysis, ATR-IR and HR-MS. The complex was investigated as a catalyst for ethylene polymerization and compared with 2,6-[(3,5-Me2pz)CH2]2py}VCl3 to explore the effect of the substituent on the pyrazolyl rings on ethylene polymerization. High catalytic activity was observed at ambient temperature. After treatment with AlEtCl2, these complexes showed high activity for ethylene polymerization converting ethylene to highly linear polyethylene and affording high molecular weight polymers (up to 1.0 × 106 g/mol) with unimodal molecular weight distributions. Full article
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Open AccessArticle Chemical Constituents of the Root of Jasminum giraldii
Molecules 2013, 18(4), 4766-4775; doi:10.3390/molecules18044766
Received: 1 February 2013 / Revised: 26 March 2013 / Accepted: 12 April 2013 / Published: 22 April 2013
Cited by 7 | PDF Full-text (264 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Two new compounds, ethylconiferin (1) and (−)-lariciresinol 4-(6'''-O-cinnamyl-β-d-glucopyranoside) (2), along with the three known compounds (+)-pinoresinol (3), (+)-cycloolivil (4), nobiletin (5), were isolated from the root of Jasminum girialdii
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Two new compounds, ethylconiferin (1) and (−)-lariciresinol 4-(6'''-O-cinnamyl-β-d-glucopyranoside) (2), along with the three known compounds (+)-pinoresinol (3), (+)-cycloolivil (4), nobiletin (5), were isolated from the root of Jasminum girialdii. All these compounds were isolated for the first time from this source. Their structures were elucidated on the basis of extensive spectroscopic analysis and chemical methods. In addition, the in vitro cytotoxic activity of these compounds was evaluated. The results showed that none of the compounds had any significant inhibitory activities on the proliferation of HCT-116 and SW-620 cells. Full article
(This article belongs to the Section Natural Products)
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Open AccessArticle Computational Modeling of the Size Effects on the Optical Vibrational Modes of H-Terminated Ge Nanostructures
Molecules 2013, 18(4), 4776-4785; doi:10.3390/molecules18044776
Received: 16 January 2013 / Revised: 16 April 2013 / Accepted: 18 April 2013 / Published: 22 April 2013
Cited by 5 | PDF Full-text (974 KB) | HTML Full-text | XML Full-text
Abstract
The vibrational dispersion relations of porous germanium (pGe) and germanium nanowires (GeNWs) were calculated using the ab initio density functional perturbation theory with a generalized gradient approximation with norm-conserving pseudopotentials. Both pores and nanowires were modeled using the supercell technique. All of the
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The vibrational dispersion relations of porous germanium (pGe) and germanium nanowires (GeNWs) were calculated using the ab initio density functional perturbation theory with a generalized gradient approximation with norm-conserving pseudopotentials. Both pores and nanowires were modeled using the supercell technique. All of the surface dangling bonds were saturated with hydrogen atoms. To address the difference in the confinement between the pores and the nanowires, we calculated the vibrational density of states of the two materials. The results indicate that there is a slight shift in the highest optical mode of the Ge-Ge vibration interval in all of the nanostructures due to the phonon confinement effects. The GeNWs exhibit a reduced phonon confinement compared with the porous Ge due to the mixed Ge-dihydride vibrational modes around the maximum bulk Ge optical mode of approximately 300 cm−1; however, the general effects of such confinements could still be noticed, such as the shift to lower frequencies of the highest optical mode belonging to the Ge vibrations. Full article
(This article belongs to the Special Issue Computational Chemistry)
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Open AccessArticle 1H-MAS-NMR Chemical Shifts in Hydrogen-Bonded Complexes of Chlorophenols (Pentachlorophenol, 2,4,6-Trichlorophenol, 2,6-Dichlorophenol, 3,5-Dichlorophenol, and p-Chlorophenol) and Amine, and H/D Isotope Effects on 1H-MAS-NMR Spectra
Molecules 2013, 18(4), 4786-4802; doi:10.3390/molecules18044786
Received: 1 March 2013 / Revised: 12 April 2013 / Accepted: 18 April 2013 / Published: 22 April 2013
Cited by 2 | PDF Full-text (564 KB) | HTML Full-text | XML Full-text
Abstract
Chemical shifts (CS) of the 1H nucleus in N···H···O type hydrogen bonds (H-bond) were observed in some complexes between chlorophenols [pentachlorophenol (PCP), 2,4,6-tricholorophenol (TCP), 2,6-dichlorophenol (26DCP), 3,5-dichlorophenol (35DCP), and p-chlorophenol (pCP)] and nitrogen-base (N-Base) by solid-state high-resolution 1H-NMR
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Chemical shifts (CS) of the 1H nucleus in N···H···O type hydrogen bonds (H-bond) were observed in some complexes between chlorophenols [pentachlorophenol (PCP), 2,4,6-tricholorophenol (TCP), 2,6-dichlorophenol (26DCP), 3,5-dichlorophenol (35DCP), and p-chlorophenol (pCP)] and nitrogen-base (N-Base) by solid-state high-resolution 1H-NMR with the magic-angle-spinning (MAS) method. Employing N-Bases with a wide range of pKa values (0.65–10.75), 1H-MAS-NMR CS values of bridging H atoms in H-bonds were obtained as a function of the N-Base’s pKa. The result showed that the CS values were increased with increasing pKa values in a range of DpKa < 0 [DpKa = pKa(N-Base) - pKa(chlorophenols)] and decreased when DpKa > 2: The maximum CS values was recorded in the PCP (pKa = 5.26)–4-methylpyridine (6.03), TCP (6.59)–imidazole (6.99), 26DCP (7.02)–2-amino-4-methylpyridine (7.38), 35DCP (8.04)–4-dimethylaminopyridine (9.61), and pCP (9.47)–4-dimethylaminopyridine (9.61) complexes. The largest CS value of 18.6 ppm was recorded in TCP–imidazole crystals. In addition, H/D isotope effects on 1H-MAS-NMR spectra were observed in PCP–2-amino-3-methylpyridine. Based on the results of CS simulation using a B3LYP/6-311+G** function, it can be explained that a little changes of the N–H length in H-bond contribute to the H/D isotope shift of the 1H-MAS-NMR peaks. Full article
(This article belongs to the Special Issue Isotope Effects)
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Open AccessArticle Intravenous and Subcutaneous Toxicity and Absorption Kinetics in Mice and Dogs of the Antileishmanial Triterpene Saponin PX-6518
Molecules 2013, 18(4), 4803-4815; doi:10.3390/molecules18044803
Received: 16 February 2013 / Revised: 7 April 2013 / Accepted: 19 April 2013 / Published: 22 April 2013
PDF Full-text (939 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The intravenous (IV) and subcutaneous (SC) toxicity and absorption kinetics of the antileishmanial triterpene saponin PX-6518 and its active constituents maesabalide-III and -IV were studied in mice and dogs. A high-dose wash-out study of PX-6518 at 20 mg/kg SC for 5 days and
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The intravenous (IV) and subcutaneous (SC) toxicity and absorption kinetics of the antileishmanial triterpene saponin PX-6518 and its active constituents maesabalide-III and -IV were studied in mice and dogs. A high-dose wash-out study of PX-6518 at 20 mg/kg SC for 5 days and a single low-dose wash-out study at 1, 2.5 or 5 mg/kg SC and IV with follow-up until day 35 after treatment were performed in mice. Beagle dogs received three escalating doses of maesabalide-III and -IV at weekly intervals (0.01, 0.1 and 0.5 mg/kg IV and maesabalide-III was also dosed SC at 0.1, 0.2 and 0.4 mg/kg). Endpoint measurements included clinical, hematological and serum biochemical parameters. Pathology and toxicokinetic studies were performed on the dogs. Whereas the neutrophils and aspartate aminotransferase and alanine aminotransferase levels were increased in the high-dose wash-out mouse study, these parameters did not change in the low-dose wash-out study. The dogs were far more susceptible than mice to liver toxicity (hepatocellular necrosis and elevated liver enzymes) and developed a painful inflammatory reaction at the SC injection site. Toxicokinetic analysis revealed a non dose-linear systemic availability with plasma concentrations above the antileishmanial IC50 after only a single dose at 0.01 mg/kg IV or 0.1 mg/kg SC. Related to the long half-life (T1/2 71–91 h after SC dosing), repeated dosing at weekly intervals may result in drug accumulation and enhanced toxicity. It was decided not to pursue further drug development for PX-6518 because of the hepatotoxic risk. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids)
Open AccessArticle Theoretical Analysis on the Kinetic Isotope Effects of Bimolecular Nucleophilic Substitution (SN2) Reactions and Their Temperature Dependence
Molecules 2013, 18(4), 4816-4843; doi:10.3390/molecules18044816
Received: 13 March 2013 / Revised: 3 April 2013 / Accepted: 18 April 2013 / Published: 23 April 2013
Cited by 5 | PDF Full-text (458 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Factors affecting the kinetic isotope effects (KIEs) of the gas-phase SN2 reactions and their temperature dependence have been analyzed using the ion-molecule collision theory and the transition state theory (TST). The quantum-mechanical tunneling effects were also considered using the canonical variational
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Factors affecting the kinetic isotope effects (KIEs) of the gas-phase SN2 reactions and their temperature dependence have been analyzed using the ion-molecule collision theory and the transition state theory (TST). The quantum-mechanical tunneling effects were also considered using the canonical variational theory with small curvature tunneling (CVT/SCT). We have benchmarked a few ab initio and density functional theory (DFT) methods for their performance in predicting the deuterium KIEs against eleven experimental values. The results showed that the MP2/aug-cc-pVDZ method gave the most accurate prediction overall. The slight inverse deuterium KIEs usually observed for the gas-phase SN2 reactions at room temperature were due to the balance of the normal rotational contribution and the significant inverse vibrational contribution. Since the vibrational contribution is a sensitive function of temperature while the rotation contribution is temperature independent, the KIEs are thus also temperature dependent. For SN2 reactions with appreciable barrier heights, the tunneling effects were predicted to contribute significantly both to the rate constants and to the carbon-13, and carbon-14 KIEs, which suggested important carbon atom tunneling at and below room temperature. Full article
(This article belongs to the Special Issue Isotope Effects)
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Open AccessReview A Survey of Marine Natural Compounds and Their Derivatives with Anti-Cancer Activity Reported in 2011
Molecules 2013, 18(4), 3641-3673; doi:10.3390/molecules18043641
Received: 14 February 2013 / Revised: 7 March 2013 / Accepted: 11 March 2013 / Published: 25 March 2013
Cited by 35 | PDF Full-text (409 KB) | HTML Full-text | XML Full-text
Abstract
Cancer continues to be a major public health problem despite the efforts that have been made in the search for novel drugs and treatments. The current sources sought for the discovery of new molecules are plants, animals and minerals. During the past decade,
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Cancer continues to be a major public health problem despite the efforts that have been made in the search for novel drugs and treatments. The current sources sought for the discovery of new molecules are plants, animals and minerals. During the past decade, the search for anticancer agents of marine origin to fight chemo-resistance has increased greatly. Each year, several novel anticancer molecules are isolated from marine organisms and represent a renewed hope for cancer therapy. The study of structure-function relationships has allowed synthesis of analogues with increased efficacy and less toxicity. In this report, we aim to review 42 compounds of marine origin and their derivatives that were published in 2011 as promising anticancer compounds. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessReview Steroidal Triterpenes of Cholesterol Synthesis
Molecules 2013, 18(4), 4002-4017; doi:10.3390/molecules18044002
Received: 18 February 2013 / Revised: 19 March 2013 / Accepted: 27 March 2013 / Published: 4 April 2013
Cited by 17 | PDF Full-text (275 KB) | HTML Full-text | XML Full-text
Abstract
Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts
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Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts by conversion of acyclic squalene into lanosterol, the first sterol intermediate of the pathway, followed by production of 20 structurally very similar steroidal triterpene molecules in over 11 complex enzyme reactions. Due to the structural similarities of sterol intermediates and the broad substrate specificity of the enzymes involved (especially sterol-Δ24-reductase; DHCR24) the exact sequence of the reactions between lanosterol and cholesterol remains undefined. This article reviews all hitherto known structures of post-squalene steroidal triterpenes of cholesterol synthesis, their biological roles and the enzymes responsible for their synthesis. Furthermore, it summarises kinetic parameters of enzymes (Vmax and Km) and sterol intermediate concentrations from various tissues. Due to the complexity of the post-squalene cholesterol synthesis pathway, future studies will require a comprehensive meta-analysis of the pathway to elucidate the exact reaction sequence in different tissues, physiological or disease conditions. A major reason for the standstill of detailed late cholesterol synthesis research was the lack of several steroidal triterpene standards. We aid to this efforts by summarizing commercial and laboratory standards, referring also to chemical syntheses of meiosis-activating sterols. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids)
Open AccessReview The Third Dimension of Reading the Sugar Code by Lectins: Design of Glycoclusters with Cyclic Scaffolds as Tools with the Aim to Define Correlations between Spatial Presentation and Activity
Molecules 2013, 18(4), 4026-4053; doi:10.3390/molecules18044026
Received: 11 March 2013 / Revised: 22 March 2013 / Accepted: 1 April 2013 / Published: 4 April 2013
Cited by 37 | PDF Full-text (847 KB) | HTML Full-text | XML Full-text
Abstract
Coding of biological information is not confined to nucleic acids and proteins. Endowed with the highest level of structural versatility among biomolecules, the glycan chains of cellular glycoconjugates are well-suited to generate molecular messages/signals in a minimum of space. The sequence and shape
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Coding of biological information is not confined to nucleic acids and proteins. Endowed with the highest level of structural versatility among biomolecules, the glycan chains of cellular glycoconjugates are well-suited to generate molecular messages/signals in a minimum of space. The sequence and shape of oligosaccharides as well as spatial aspects of multivalent presentation are assumed to underlie the natural specificity/selectivity that cellular glycans have for endogenous lectins. In order to eventually unravel structure-activity profiles cyclic scaffolds have been used as platforms to produce glycoclusters and afford valuable tools. Using adhesion/growth-regulatory galectins and the pan-galectin ligand lactose as a model, emerging insights into the potential of cyclodextrins, cyclic peptides, calixarenes and glycophanes for this purpose are presented herein. The systematic testing of lectin panels with spatially defined ligand presentations can be considered as a biomimetic means to help clarify the mechanisms, which lead to the exquisite accuracy at which endogenous lectins select their physiological counterreceptors from the complexity of the cellular glycome. Full article
(This article belongs to the Special Issue Calixarenes and Resorcinarenes)
Open AccessReview Protostane and Fusidane Triterpenes: A Mini-Review
Molecules 2013, 18(4), 4054-4080; doi:10.3390/molecules18044054
Received: 6 March 2013 / Revised: 29 March 2013 / Accepted: 1 April 2013 / Published: 5 April 2013
Cited by 14 | PDF Full-text (409 KB) | HTML Full-text | XML Full-text
Abstract
Protostane triterpenes belong to a group of tetracyclic triterpene that exhibit unique structural characteristics. Their natural distribution is primarily limited to the genus Alisma of the Alismataceae family, but they have also been occasionally found in other plant genera such as Lobelia,
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Protostane triterpenes belong to a group of tetracyclic triterpene that exhibit unique structural characteristics. Their natural distribution is primarily limited to the genus Alisma of the Alismataceae family, but they have also been occasionally found in other plant genera such as Lobelia, Garcinia, and Leucas. To date, there are 59 known protostane structures. Many of them have been reported to possess biological properties such as improving lipotropism, hepatoprotection, anti-viral activity against hepatitis B and HIV-I virus, anti-cancer activity, as well as reversal of multidrug resistance in cancer cells. On the other hand, fusidanes are fungal products characterized by 29-nor protostane structures. They possess antibiotic properties against staphylococci, including the methicillin-resistant Staphylococcus aureus (MRSA). Fusidic acid is a representative member which has found clinical applications. This review covers plant sources of the protostanes, their structure elucidation, characteristic structural and spectral properties, as well as biological activities. The fungal sources, structural features, biological activities of fusidanes are also covered in this review. Additionally, the biogenesis of these two types of triterpenes is discussed and a refined pathway is proposed. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids)
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Open AccessReview Coordination Programming of Photofunctional Molecules
Molecules 2013, 18(4), 4091-4119; doi:10.3390/molecules18044091
Received: 23 January 2013 / Revised: 15 March 2013 / Accepted: 27 March 2013 / Published: 5 April 2013
Cited by 13 | PDF Full-text (1893 KB) | HTML Full-text | XML Full-text
Abstract
Our recent achievements relating to photofunctional molecules are addressed. Section 1 discloses a new concept of photoisomerization. Pyridylpyrimidine-copper complexes undergo a ring inversion that can be modulated by the redox state of the copper center. In combination with an intermolecular photoelectron transfer (PET)
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Our recent achievements relating to photofunctional molecules are addressed. Section 1 discloses a new concept of photoisomerization. Pyridylpyrimidine-copper complexes undergo a ring inversion that can be modulated by the redox state of the copper center. In combination with an intermolecular photoelectron transfer (PET) initiated by the metal-to-ligand charge transfer (MLCT) transition of the Cu(I) state, we realize photonic regulation of the ring inversion. Section 2 reports on the first examples of heteroleptic bis(dipyrrinato)zinc(II) complexes. Conventional homoleptic bis(dipyrrinato)zinc(II) complexes suffered from low fluorescence quantum yields, whereas the heteroleptic ones feature bright fluorescence even in polar solvents. Section 3 describes our new findings on Pechmann dye, which was first synthesized in 1882. New synthetic procedures for Pechmann dye using dimethyl bis(arylethynyl)fumarate as a starting material gives rise to its new structural isomer. We also demonstrate potentiality of a donor-acceptor-donor type of Pechmann dye in organic electronics. Full article
(This article belongs to the Special Issue New Trends in Photochemistry)
Open AccessReview Chemical Methods for Peptide and Protein Production
Molecules 2013, 18(4), 4373-4388; doi:10.3390/molecules18044373
Received: 12 March 2013 / Revised: 28 March 2013 / Accepted: 9 April 2013 / Published: 12 April 2013
Cited by 33 | PDF Full-text (408 KB) | HTML Full-text | XML Full-text
Abstract
Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling
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Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported a-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry. Full article
(This article belongs to the Special Issue Chemical Protein and Peptide Synthesis)
Open AccessReview H/D Isotope Effects in Hydrogen Bonded Systems
Molecules 2013, 18(4), 4467-4476; doi:10.3390/molecules18044467
Received: 26 February 2013 / Revised: 18 March 2013 / Accepted: 5 April 2013 / Published: 16 April 2013
Cited by 22 | PDF Full-text (562 KB) | HTML Full-text | XML Full-text
Abstract
An extremely strong H/D isotope effect observed in hydrogen bonded A-HB systems is connected with a reach diversity of the potential shape for the proton/deuteron motion. It is connected with the anharmonicity of the proton/deuteron vibrations and of the tunneling effect,
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An extremely strong H/D isotope effect observed in hydrogen bonded A-HB systems is connected with a reach diversity of the potential shape for the proton/deuteron motion. It is connected with the anharmonicity of the proton/deuteron vibrations and of the tunneling effect, particularly in cases of short bridges with low barrier for protonic and deuteronic jumping. Six extreme shapes of the proton motion are presented starting from the state without possibility of the proton transfer up to the state with a full ionization. The manifestations of the H/D isotope effect are best reflected in the infra-red absorption spectra. A most characteristic is the run of the relationship between the isotopic ratio nH/nD and position of the absorption band shown by using the example of NHN hydrogen bonds. One can distinguish a critical range of correlation when the isotopic ratio reaches the value of ca. 1 and then increases up to unusual values higher than . The critical range of the isotope effect is also visible in NQR and NMR spectra. In the critical region one observes a stepwise change of the NQR frequency reaching 1.1 MHz. In the case of NMR, the maximal isotope effect is reflected on the curve presenting the dependence of Δd (1H,2H) on d (1H). This effect corresponds to the range of maximum on the correlation curve between dH and ΔpKa that is observed in various systems. There is a lack in the literature of quantitative information about the influence of isotopic substitution on the dielectric properties of hydrogen bond except the isotope effect on the ferroelectric phase transition in some hydrogen bonded crystals. Full article
(This article belongs to the Special Issue Isotope Effects)
Open AccessReview Applications of Biomaterials to Liquid Crystals
Molecules 2013, 18(4), 4703-4717; doi:10.3390/molecules18044703
Received: 17 January 2013 / Revised: 10 April 2013 / Accepted: 17 April 2013 / Published: 19 April 2013
Cited by 12 | PDF Full-text (369 KB) | HTML Full-text | XML Full-text
Abstract
Nowadays, chemically synthesized proteins and peptides are attractive building blocks and have potential in many important applications as biomaterials. In this review, applications of biomaterials to thermotropic liquid crystals are discussed. The review covers the improvement of the performance of liquid crystal displays
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Nowadays, chemically synthesized proteins and peptides are attractive building blocks and have potential in many important applications as biomaterials. In this review, applications of biomaterials to thermotropic liquid crystals are discussed. The review covers the improvement of the performance of liquid crystal displays using liquid crystal physical gels consisting of a liquid crystal and amino acid-based gelators, and also new functionalization of liquid crystals. Moreover, the influence of DNA, which is one of the more attractive biomaterials, dispersed in thermotropic liquid crystals and its potential use in the liquid crystal industry is described. In addition, we found interesting results during electrooptical measurements of liquid crystals doped with DNA, and explain them from the point of view of biological applications. These recent approaches suggest that these biomaterials may be applicable in the electronic device industry and should be considered as an interesting material with their physical properties having the potential to create or refine an industrial product. Full article
(This article belongs to the Special Issue Chemical Protein and Peptide Synthesis)
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Open AccessReview Application of the Suzuki-Miyaura Reaction in the Synthesis of Flavonoids
Molecules 2013, 18(4), 4739-4765; doi:10.3390/molecules18044739
Received: 19 March 2013 / Revised: 10 April 2013 / Accepted: 19 April 2013 / Published: 22 April 2013
Cited by 18 | PDF Full-text (350 KB) | HTML Full-text | XML Full-text
Abstract
The application of the Suzuki-Miyaura reaction in the synthesis of flavonoids, an important class of natural products, is reviewed. This reaction has not only been employed to provide access to flavonoid nuclei, but has also been applied to the synthesis of dimeric flavonoids
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The application of the Suzuki-Miyaura reaction in the synthesis of flavonoids, an important class of natural products, is reviewed. This reaction has not only been employed to provide access to flavonoid nuclei, but has also been applied to the synthesis of dimeric flavonoids and in the synthesis of libraries of flavonoid derivatives for biological activity studies. The classes of flavonoids that are discussed are the chalcones, flavones, isoflavones, neoflavones, biflavones and derivatives of flavonoids obtained by C-C bond formation via the Suzuki-Miyaura reaction. Full article
(This article belongs to the Special Issue Suzuki Reaction)

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Open AccessRetraction Retraction: Sasidharan et al. Evaluation of the Hepatoprotective Effects of Lantadene A, a Pentacyclic Triterpenoid of Lantana Plants against Acetaminophen-induced Liver Damage. Molecules 2012, 17, 13937-13947
Molecules 2013, 18(4), 3839-3840; doi:10.3390/molecules18043839
Received: 17 March 2013 / Revised: 18 March 2013 / Accepted: 18 March 2013 / Published: 27 March 2013
PDF Full-text (107 KB) | HTML Full-text | XML Full-text
Abstract
A recent Comment by M. Sharma published in the journal Molecules [1] raises issues with our previously published paper [2]. After reviewing its content, and although we respectfully stand by our experimental description whereby we were able to prepare stock and working solutions
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A recent Comment by M. Sharma published in the journal Molecules [1] raises issues with our previously published paper [2]. After reviewing its content, and although we respectfully stand by our experimental description whereby we were able to prepare stock and working solutions of the substance being tested, the arguments presented do raise concerns about the true identity of the compound actually used and hence the results and conclusions of our paper. Full article

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