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Molecules, Volume 12, Issue 8 (August 2007), Pages 1548-2088

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Editorial

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Open AccessEditorial Full Open Access Publishing Policy Imposed in 2007: Molecules Publishes Many More Papers This Year – More than 2000 Pages Published up to Issue 8
Molecules 2007, 12(8), 2001-2002; doi:10.3390/12082001
Received: 20 August 2007 / Published: 22 August 2007
Cited by 5 | PDF Full-text (20 KB) | HTML Full-text | XML Full-text

Research

Jump to: Editorial, Review

Open AccessArticle Leishmanicidal and Cholinesterase Inhibiting Activities of Phenolic Compounds from Allanblackia monticola and Symphonia globulifera
Molecules 2007, 12(8), 1548-1557; doi:10.3390/12081548
Received: 15 May 2007 / Revised: 8 July 2007 / Accepted: 9 July 2007 / Published: 20 July 2007
Cited by 42 | PDF Full-text (68 KB) | HTML Full-text | XML Full-text
Abstract
In a preliminary antiprotozoal screening of several Clusiaceae species, the methanolic extracts of Allanblackia monticola and Symphonia globulifera showed high in vitro leishmanicidal activity. Further bioguided phytochemical investigation led to the isolation of four benzophenones: guttiferone A (1), garcinol (2), cambogin (3) [...] Read more.
In a preliminary antiprotozoal screening of several Clusiaceae species, the methanolic extracts of Allanblackia monticola and Symphonia globulifera showed high in vitro leishmanicidal activity. Further bioguided phytochemical investigation led to the isolation of four benzophenones: guttiferone A (1), garcinol (2), cambogin (3) and guttiferone F (4), along with three xanthones: allanxanthone A (5), xanthone V1 (6) and globulixanthone C (7) as active constituents. Compounds 1 and 6 were isolated from S. globulifera leaves, while compounds 2-5 were obtained from A. monticola fruits. Guttiferone A (1) and F (4) showed particulary strong leishmanicidal activity in vitro, with IC50 values (0.2 μM and 0.16 μM, respectively) comparable to that of the reference compound, miltefosine (0.46 μM). Although the leishmanicidal activity is promising, the cytotoxicity profile of these compounds prevent at this state further in vivo biological evaluation. In addition, all the isolated compounds were tested in vitro for their anticholinesterase properties. The four benzophenones showed potent anticholinesterase properties towards acetylcholinesterase (AChE) and butylcholinesterase (AChE). For AChE, the IC50 value (0.66 μM) of garcinol (2) was almost equal to that of the reference compound galanthamine (0.50 μM). Furthermore, guttiferone A (1) and guttiferone F (4) (IC50 = 2.77 and 3.50 μM, respectively) were more active than galanthamine (IC50 = 8.5) against BChE. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Heterocycles [h]Fused onto 4-Oxoquinoline-3-Carboxylic Acid, Part IV. Convenient Synthesis of Substituted Hexahydro [1,4]Thiazepino[2,3-h]quinoline-9-carboxylic Acid and Its Tetrahydroquino[7,8-b]benzothiazepine Homolog
Molecules 2007, 12(8), 1558-1568; doi:10.3390/12081558
Received: 4 June 2007 / Revised: 19 July 2007 / Accepted: 19 July 2007 / Published: 27 July 2007
Cited by 9 | PDF Full-text (90 KB) | HTML Full-text | XML Full-text
Abstract
Substituted [1,4]thiazepino[2,3-h]quinolinecarboxylic acid 3 is prepared by PPA-catalyzed thermal lactamization of the respective 8-amino-7-[(2-carboxyethyl)thio]- 1,4-dihydroquinoline-3-carboxylic acid 9. The latter synthon is obtained by reduction of the 8-nitro-1,4-dihydroquinoline precursor 8 which, in turn, is made accessible via interaction of 3-mercaptopropionic acid [...] Read more.
Substituted [1,4]thiazepino[2,3-h]quinolinecarboxylic acid 3 is prepared by PPA-catalyzed thermal lactamization of the respective 8-amino-7-[(2-carboxyethyl)thio]- 1,4-dihydroquinoline-3-carboxylic acid 9. The latter synthon is obtained by reduction of the 8-nitro-1,4-dihydroquinoline precursor 8 which, in turn, is made accessible via interaction of 3-mercaptopropionic acid with 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-1,4- dihydroquinoline-3-carboxylic acid 7 in the presence of triethylamine. A benzo-homolog of 3, namely tetrahydroquino[7,8-b]benzothiazepine-3-carboxylic acid 6, is analogously prepared via the raction of 2-mercaptobenzoic acid with 7, followed by reduction of the resulting 7-[(2-carboxyphenyl)thio]-8-nitro product 10 into the corresponding 8-amino derivative 11, and subsequent lactamization. The structures assigned to 3, 6 and 8-11 are based on microanalytical and spectral (IR, MS, NMR) data. Full article
Open AccessArticle Synthesis and Biological Activity of Some Novel Derivatives of 4-Amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole
Molecules 2007, 12(8), 1596-1605; doi:10.3390/12081596
Received: 30 May 2007 / Revised: 25 July 2007 / Accepted: 25 July 2007 / Published: 27 July 2007
Cited by 21 | PDF Full-text (111 KB) | HTML Full-text | XML Full-text
Abstract
To discover new 1,2,4-triazole derivatives which may possess significant biological activities, we synthesized a series of novel 6-aryl-3-(D-galactopentitol-1-yl)- 7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galactopentitol- 1-yl)-3-mercapto-4H-1,2,4-triazoles from 4-amino-3-(D-galactopentitol-1-yl)-5- mercapto-1,2,4-triazole. All the title compounds were characterized by elemental analysis, IR, 1 [...] Read more.
To discover new 1,2,4-triazole derivatives which may possess significant biological activities, we synthesized a series of novel 6-aryl-3-(D-galactopentitol-1-yl)- 7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galactopentitol- 1-yl)-3-mercapto-4H-1,2,4-triazoles from 4-amino-3-(D-galactopentitol-1-yl)-5- mercapto-1,2,4-triazole. All the title compounds were characterized by elemental analysis, IR, 1H- and 13C-NMR. Plant growth-regulating activity tests showed that these compounds have remarkable effects on the growth of radish and wheat. Full article
Open AccessArticle Antibacterial Thymol Derivatives Isolated from Centipeda minima
Molecules 2007, 12(8), 1606-1613; doi:10.3390/12081606
Received: 19 June 2007 / Revised: 3 July 2007 / Accepted: 3 July 2007 / Published: 27 July 2007
Cited by 22 | PDF Full-text (89 KB) | HTML Full-text | XML Full-text
Abstract
Two new monoterpenoids, 8,10-dihydroxy-9(2)-methylbutyryloxythymol (1) and 10-hydroxy-8,9-dioxyisopropylidene-thymol (2), together with five known thymol derivatives: 8,9,10-trihydroxythymol (3), thymol-β-glucopyranoside (4), 9-hydroxythymol (5), 8,10-dihydroxy-9-isobutyryloxythymol (6), and 8-hydroxy-9,10-diisobutyryloxythymol (7), were isolated from Centipeda minima. Their structures were identified by means of spectroscopic analyses. [...] Read more.
Two new monoterpenoids, 8,10-dihydroxy-9(2)-methylbutyryloxythymol (1) and 10-hydroxy-8,9-dioxyisopropylidene-thymol (2), together with five known thymol derivatives: 8,9,10-trihydroxythymol (3), thymol-β-glucopyranoside (4), 9-hydroxythymol (5), 8,10-dihydroxy-9-isobutyryloxythymol (6), and 8-hydroxy-9,10-diisobutyryloxythymol (7), were isolated from Centipeda minima. Their structures were identified by means of spectroscopic analyses. Interestingly, compound 2 is not an extraction artifact according to a close HPLC examination of material after extraction by analytical MeOH at ambient temperature. The antibacterial activities of compounds 1-7 were evaluated against eight microbial strains by the agar dilution method. Full article
Open AccessArticle Characterization of Phenolic Compounds in Pinus laricio Needles and Their Responses to Prescribed Burnings
Molecules 2007, 12(8), 1614-1622; doi:10.3390/12081614
Received: 30 May 2007 / Revised: 19 July 2007 / Accepted: 19 July 2007 / Published: 30 July 2007
Cited by 19 | PDF Full-text (54 KB) | HTML Full-text | XML Full-text
Abstract
Fire is a dominant ecological factor in Mediterranean-type ecosystems. Management strategies include prescribed (controlled) burning, which has been used in the management of several species, such as Pinus nigra ssp laricio var. Corsicana, a pine endemic to Corsica of great ecological [...] Read more.
Fire is a dominant ecological factor in Mediterranean-type ecosystems. Management strategies include prescribed (controlled) burning, which has been used in the management of several species, such as Pinus nigra ssp laricio var. Corsicana, a pine endemic to Corsica of great ecological and economic importance. The effects of prescribed burning on Pinus laricio have been little studied. The first aim of this study was to characterize total and simple phenolic compounds in Pinus laricio. The second aim was to understand: i) the short term (one to three months) and medium term (three years) effects of prescribed burning, and ii) the effects of periodic prescribed burning on the production of phenolic compounds in Pinus laricio. The first result of this study is the presence of total and simple phenolic compounds in the needles of Pinus laricio. 3-Vanillyl propanol is the major compound. After a prescribed burning, the synthesis of total phenolic compounds increases in Pinus laricio for a period of three months. Total phenolic compounds could be used as bioindicators for the short-term response of Pinus laricio needles to prescribed burning. Simple phenolic compounds do not seem to be good indicators of the impact of prescribed burning because prescribed burnings are low in intensity. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle o-Quinonoid Heterocycles: Synthesis and Crystal Structure of 2,3-Dicyano-5,7-bismethylthieno[3,4-b]pyrazine
Molecules 2007, 12(8), 1623-1631; doi:10.3390/12081623
Received: 1 June 2007 / Revised: 20 July 2007 / Accepted: 20 July 2007 / Published: 30 July 2007
Cited by 2 | PDF Full-text (203 KB) | HTML Full-text | XML Full-text
Abstract
2,3-Dicyano-5,7-bismethylthieno[3,4-b]pyrazine (5), has been obtained as a minor product from reactions of S-nucleophiles with 5,6-di(1-bromoethyl)pyrazine-2,3- dicarbonitrile (3), or from a condensation of 4-hydroxy-2,5-dimethyl-2,3-dihydrothiophen- 3-one (4) with diaminomaleonitrile. The molecular structure of compound 5 has been confirmed by X-ray diffraction. A partial [...] Read more.
2,3-Dicyano-5,7-bismethylthieno[3,4-b]pyrazine (5), has been obtained as a minor product from reactions of S-nucleophiles with 5,6-di(1-bromoethyl)pyrazine-2,3- dicarbonitrile (3), or from a condensation of 4-hydroxy-2,5-dimethyl-2,3-dihydrothiophen- 3-one (4) with diaminomaleonitrile. The molecular structure of compound 5 has been confirmed by X-ray diffraction. A partial separation of charge causes a donor-acceptor type arrangement of the planar molecules in uniform parallel stacks with an interplanar spacing of 3.334(2) Å at 100 K. Full article
(This article belongs to the Special Issue Heterocycles)
Open AccessArticle Novel and Efficient Synthesis of N,N-Dialkylaminoand O-alkylphenyl-2-(1-alkyl/phenyl-2-oxopropylidene) Phosphonohydrazido Oximes - Potential Marine Fish Toxin Analogues. Part 2
Molecules 2007, 12(8), 1632-1640; doi:10.3390/12081632
Received: 6 July 2007 / Revised: 26 July 2007 / Accepted: 26 July 2007 / Published: 2 August 2007
Cited by 1 | PDF Full-text (67 KB) | HTML Full-text | XML Full-text
Abstract
A novel and efficient method for the synthesis of N,N-dialkylamino/O-alkyl phenyl-2-(1-alkyl/phenyl-2-oxopropylidene) phosphonohydrazido oximes 4 using activated silica has been developed. The reaction involves the condensation of substituted α- ketooxime and N,N-dialkylaminophenylphosphonohydrazides or O-alkylphenylphosphonohydrazides and gave the corresponding [...] Read more.
A novel and efficient method for the synthesis of N,N-dialkylamino/O-alkyl phenyl-2-(1-alkyl/phenyl-2-oxopropylidene) phosphonohydrazido oximes 4 using activated silica has been developed. The reaction involves the condensation of substituted α- ketooxime and N,N-dialkylaminophenylphosphonohydrazides or O-alkylphenylphosphonohydrazides and gave the corresponding phosphonohydrazido oximes in excellent yields under mild conditions. Full article
Open AccessCommunication Aqueous Ti(IV)-Catalyzed Diels-Alder Reaction
Molecules 2007, 12(8), 1674-1678; doi:10.3390/12081674
Received: 23 July 2007 / Revised: 2 August 2007 / Accepted: 3 August 2007 / Published: 4 August 2007
Cited by 4 | PDF Full-text (35 KB) | HTML Full-text | XML Full-text
Abstract
The aqueous Diels-Alder reaction of 1,3-cyclohexadiene with 1,4-benzoquinone was compared and contrasted to the same reaction catalyzed with Flextyl P™, a novel Ti(IV) performance catalyst. The catalyst improved conversion by 22% versus the uncatalyzed reaction and represents a rare example of a [...] Read more.
The aqueous Diels-Alder reaction of 1,3-cyclohexadiene with 1,4-benzoquinone was compared and contrasted to the same reaction catalyzed with Flextyl P™, a novel Ti(IV) performance catalyst. The catalyst improved conversion by 22% versus the uncatalyzed reaction and represents a rare example of a Ti(IV) catalyzed Diels-Alder reaction in water. Full article
Open AccessArticle Synthesis, Antibacterial, Antifungal and Antiviral Activity Evaluation of Some New bis-Schiff Bases of Isatin and Their Derivatives
Molecules 2007, 12(8), 1720-1730; doi:10.3390/12081720
Received: 11 April 2007 / Revised: 13 May 2007 / Accepted: 15 May 2007 / Published: 7 August 2007
Cited by 101 | PDF Full-text (84 KB) | HTML Full-text | XML Full-text
Abstract
Twelve new bis-Schiff bases of isatin, benzylisatin and 5-fluoroisatin 3a-3l were prepared by condensation of isatin, benzylisatin and 5-fluoroisatin with primary aromatic amines. The chemical structures of the products were confirmed by 1H- and 13CNMR, IR and mass spectral data. [...] Read more.
Twelve new bis-Schiff bases of isatin, benzylisatin and 5-fluoroisatin 3a-3l were prepared by condensation of isatin, benzylisatin and 5-fluoroisatin with primary aromatic amines. The chemical structures of the products were confirmed by 1H- and 13CNMR, IR and mass spectral data. The compounds were screened for antiviral activity against a panel of DNA and RNA viruses. Minimum cytotoxic and minimum virusinhibitory concentrations of these compounds were determined. Compounds 3c and 3i were the most cytotoxic in HEL cells. These newly synthesized bis-Schiff bases were also tested for their antibacterial and antifungal activities. They did not display activity against S. cerevisiae (ATCC 28383) or C. albicans (CIP 1180-79). Full article
Open AccessCommunication Two Step Synthesis of a Non-symmetric Acetylcholinesterase Reactivator
Molecules 2007, 12(8), 1755-1761; doi:10.3390/12081755
Received: 25 June 2007 / Revised: 1 August 2007 / Accepted: 6 August 2007 / Published: 7 August 2007
Cited by 5 | PDF Full-text (58 KB) | HTML Full-text | XML Full-text
Abstract
The newly developed and very promising acetylcholinesterase reactivator (E)-1- (2-hydroxyiminomethylpyridinium)-4-(4-hydroxyiminomethylpyridinium)-but-2-ene dibromide was prepared using two different pathways via a two-step synthesis involving the appropriate (E)-1-(4-bromobut-2-enyl)-2- or 4-hydroxyiminomethyl-pyridinium bromides. Afterwards, purities and yields of the desired product prepared by [...] Read more.
The newly developed and very promising acetylcholinesterase reactivator (E)-1- (2-hydroxyiminomethylpyridinium)-4-(4-hydroxyiminomethylpyridinium)-but-2-ene dibromide was prepared using two different pathways via a two-step synthesis involving the appropriate (E)-1-(4-bromobut-2-enyl)-2- or 4-hydroxyiminomethyl-pyridinium bromides. Afterwards, purities and yields of the desired product prepared by both routes were compared. Finally, its potency to reactivate several nerve agent-inhibited acetylcholinesterases was tested. Full article
Open AccessArticle High-Yielding Synthesis of Methyl Orthoformate-Protected Hydroxytyrosol and Its Use in Preparation of Hydroxytyrosyl Acetate
Molecules 2007, 12(8), 1762-1770; doi:10.3390/12081762
Received: 30 May 2007 / Revised: 31 July 2006 / Accepted: 1 August 2007 / Published: 8 August 2007
Cited by 6 | PDF Full-text (96 KB) | HTML Full-text | XML Full-text
Abstract
The new methyl orthoformate of the powerful antioxidant hydroxytyrosol (or 2- (3,4-dihydroxyphenyl)ethanol) has been synthesized by a two-step high yielding procedure. The protection stabilizes hydroxytyrosol against fast oxidation and allows both easy chromatographic purification and long term storage. The protective group is [...] Read more.
The new methyl orthoformate of the powerful antioxidant hydroxytyrosol (or 2- (3,4-dihydroxyphenyl)ethanol) has been synthesized by a two-step high yielding procedure. The protection stabilizes hydroxytyrosol against fast oxidation and allows both easy chromatographic purification and long term storage. The protective group is hydrolyzed over pH = 10 and below pH = 5, thus allowing the release of the active principle under physiological conditions. The use of the methyl orthoformate-protected hydroxytyrosol allows the preparation of protected hydroxytyrosyl esters, like the acetate herein reported, by selective esterification of the alcoholic function. The subsequent quantitative deprotection under non-aqueous and mild conditions affords the hydroxytyrosyl acetate in high yields. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Synthesis of Some New Anils: Part 1. Reaction of 2-Hydroxy-benzaldehyde and 2-Hydroxynaphthaldehyde with 2-Aminopyridene and 2-Aminopyrazine
Molecules 2007, 12(8), 1796-1804; doi:10.3390/12081796
Received: 24 May 2007 / Revised: 19 July 2007 / Accepted: 19 July 2007 / Published: 13 August 2007
Cited by 21 | PDF Full-text (75 KB) | HTML Full-text | XML Full-text
Abstract
New Schiff bases derived from 2-aminopyridene and 2-aminopyrazine have been synthesized. The UV-Visible spectra of the compounds have been investigated in acetonitrile and toluene. The compounds were in tautomeric equilibrium (enol-imine O– H···N, keto-amine O···H–N forms) in polar and nonpolar solvents. For [...] Read more.
New Schiff bases derived from 2-aminopyridene and 2-aminopyrazine have been synthesized. The UV-Visible spectra of the compounds have been investigated in acetonitrile and toluene. The compounds were in tautomeric equilibrium (enol-imine O– H···N, keto-amine O···H–N forms) in polar and nonpolar solvents. For some derivatives the keto-amine form was observed in both toluene and acetonitrile. 1H-NMR and IR results showed that all Schiff bases studied favor the enol-imine form over the keto form in a weakly polar solvent such as deuterochloroform. Full article
Open AccessArticle A Study on 4-Acylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones
Molecules 2007, 12(8), 1805-1816; doi:10.3390/12081805
Received: 28 May 2007 / Revised: 2 August 2007 / Accepted: 2 August 2007 / Published: 13 August 2007
Cited by 13 | PDF Full-text (149 KB) | HTML Full-text | XML Full-text
Abstract
Five novel 3-alkyl-4-phenylacetylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with phenylacetyl chloride and characterized by elemental analyses and IR, 1HNMR, 13C-NMR and UV spectral data. The newly synthesized compounds 2 were titrated potentiometrically [...] Read more.
Five novel 3-alkyl-4-phenylacetylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with phenylacetyl chloride and characterized by elemental analyses and IR, 1HNMR, 13C-NMR and UV spectral data. The newly synthesized compounds 2 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide, and the half-neutralization potential values and the corresponding pKa values were determined for all cases. In addition, these new compounds and five recently reported 3-alkyl-4-(pmethoxybenzoylamino)- 4,5-dihydro-1H-1,2,4-triazol-5-ones (3) were screened for their antioxidant activities. Full article
Open AccessArticle Synthesis of Novel Benzimidazolyl-substituted Acrylonitriles and Amidino-substituted Benzimidazo[1,2-a]Quinolines
Molecules 2007, 12(8), 1817-1828; doi:10.3390/12081817
Received: 28 June 2007 / Revised: 20 July 2007 / Accepted: 20 July 2007 / Published: 13 August 2007
Cited by 15 | PDF Full-text (105 KB) | HTML Full-text | XML Full-text
Abstract
A series of novel benzimidazole derivatives 3-10 were synthesized. Benzimidazolyl-substituted acrylonitriles 3 and 4 underwent a photochemical dehydrocyclization reaction to give the corresponding mono- and dicyano-substituted benzimidazo[1,2-a] quinolines 5 and 6. Pinner reaction of these compounds did not give the [...] Read more.
A series of novel benzimidazole derivatives 3-10 were synthesized. Benzimidazolyl-substituted acrylonitriles 3 and 4 underwent a photochemical dehydrocyclization reaction to give the corresponding mono- and dicyano-substituted benzimidazo[1,2-a] quinolines 5 and 6. Pinner reaction of these compounds did not give the expected mono- and diamidines, but rather only compounds 7-10, with amido groups at 6-position were isolated. A mechanism for the reaction is proposed. Acyclic compounds 3 and 4, as well as cyclic benzimidazo[1,2-a]quinolines 5-8, exhibit interesting spectroscopic properties and are potential biologically active compounds. Full article
Open AccessCommunication Effect of Cooking Processes on the Contents of Two Bioactive Carotenoids in Solanum lycopersicum Tomatoes and Physalis ixocarpa and Physalis philadelphica Tomatillos
Molecules 2007, 12(8), 1829-1835; doi:10.3390/12081829
Received: 21 March 2007 / Revised: 31 July 2007 / Accepted: 31 July 2007 / Published: 13 August 2007
Cited by 9 | PDF Full-text (74 KB) | HTML Full-text | XML Full-text
Abstract
Calculation of the HPLC chromatographic retention times of different carotenoids supported our improved chromatographic separation of β-carotene and lutein in four tomatoes and two tomatillo varieties in fresh form and after three different cooking procedures: pot boiling, cooking in a pressure cooker [...] Read more.
Calculation of the HPLC chromatographic retention times of different carotenoids supported our improved chromatographic separation of β-carotene and lutein in four tomatoes and two tomatillo varieties in fresh form and after three different cooking procedures: pot boiling, cooking in a pressure cooker and microwaving. A good separation was achieved experimentally using an Ultrasphere ODS column and gradient elution with an acetonitrile-tetrahydrofuran-water mobile phase. It was shown that diverse tomato species contained different amounts of β-carotene (6-400 μg/100 mg) and lutein (2-30 μg/100 mg). The concentration in fresh samples was higher than in cooked tomatoes. The β–carotene content in fresh tomatillo varied between 2 and 20 μg/100 mg. Microwaving caused partial destruction of the β-carotene and lutein in tomatillos. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Radical-scavenging Activity of the Reaction Products of Isoeugenol with Thiol, Thiophenol, Mercaptothiazoline or Mercaptomethylimidazole Using the Induction Period Method
Molecules 2007, 12(8), 1836-1844; doi:10.3390/12081836
Received: 13 July 2007 / Revised: 9 August 2007 / Accepted: 9 August 2007 / Published: 13 August 2007
Cited by 5 | PDF Full-text (92 KB) | HTML Full-text | XML Full-text
Abstract
The reaction products in the presence of Lewis acid of isoeugenol (1) with ethanethiol, thiophenol, 2-mercaptothiazoline or 2-mercapto-1-methylimidazole (ISO-S1 – ISO-S-4) were obtained. The radical-scavenging activity of these compounds was investigated using the induction period method for polymerization of methyl methacrylate (MMA) [...] Read more.
The reaction products in the presence of Lewis acid of isoeugenol (1) with ethanethiol, thiophenol, 2-mercaptothiazoline or 2-mercapto-1-methylimidazole (ISO-S1 – ISO-S-4) were obtained. The radical-scavenging activity of these compounds was investigated using the induction period method for polymerization of methyl methacrylate (MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO) and monitored by differential scanning calorimetry (DSC). For BPO, the stoichiometric factor (number of free radicals trapped by one mole of antioxidant moiety, n) declined in the order isoeugenol (1.8) > ISO-S-1 (1.6) > ISO-S-2 (1.2 ) > ISOS- 3 (0.9) > ISO-S-4 (0.3), whereas for AIBN, their n values were about 1, except for ISOS- 3 (0.6). The ratio of the rate constant of inhibition to that of propagation (kinh/kp) for BPO declined in the order ISO-S-4 (56) > ISO-S-3 (15) > ISO-S-2 (11) >ISO-S-1 (9) > isoeugenol (8). Similarly, for AIBN the kinh/kp of the reaction products (33-57) was greater than that of isoeugenol (31). The reaction products of isoeugenol with a SH group showed greater inhibition rate constants (kinh) than the parent compound isoeugenol. Full article
Open AccessArticle (-)-Epicatechin-3-gallate, a Green Tea Polyphenol Is a Potent Agent Against UVB-induced Damage in HaCaT Keratinocytes
Molecules 2007, 12(8), 1845-1858; doi:10.3390/12081845
Received: 25 May 2007 / Revised: 10 August 2007 / Accepted: 10 August 2007 / Published: 14 August 2007
Cited by 30 | PDF Full-text (386 KB) | HTML Full-text | XML Full-text
Abstract
(-)-Epicatechin-3-gallate (ECG) is a polyphenolic compound similar to (-)-epigallocatechin-3-gallate (EGCG) which is abundant in green tea. Numerous workers have proposed that EGCG protects epidermal cells against UVB-induced damage. However, little has been known about whether ECG protects keratinocytes against UVB-induced damage. We [...] Read more.
(-)-Epicatechin-3-gallate (ECG) is a polyphenolic compound similar to (-)-epigallocatechin-3-gallate (EGCG) which is abundant in green tea. Numerous workers have proposed that EGCG protects epidermal cells against UVB-induced damage. However, little has been known about whether ECG protects keratinocytes against UVB-induced damage. We decided to investigate the protective effects and underlying mechanisms of ECG on UVB-induced damage. Cell viability was determined by the MTT assay. Activation of ERK1/2, p38 and JNK was analyzed by Western blotting. Intracellular H2O2 production and DNA content was analyzed by flow cytometry. Lipid peroxidation was assayed by colorimetry. In our study, we found that ECG dose-dependently attenuated UVB-induced keratinocyte death. Moreover, ECG markedly inhibited UVB-induced cell membrane lipid peroxidation and H2O2 generation in keratinocytes, suggesting that ECG can act as a free radical scavenger when keratinocytes were photodamaged. In parallel, H2O2-induced the activation of ERK1/2, p38 and JNK in keratinocytes could be inhibited by ECG. UVB-induced pre-G1 arrest leading to apoptotic changes of keratinocytes were blocked by ECG. Taken together, we provide here evidence that ECG protects keratinocytes from UVB-induced photodamage and H2O2-induced oxidative stress, possibly through inhibition of the activation of ERK1/2, p38 and JNK and/or scavenging of free radicals. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Synthesis of Novel Steroid-Peptoid Hybrid Macrocycles by Multiple Multicomponent Macrocyclizations Including Bifunctional Building Blocks (MiBs)
Molecules 2007, 12(8), 1890-1899; doi:10.3390/12081890
Received: 24 May 2007 / Accepted: 15 August 2006 / Published: 17 August 2007
Cited by 24 | PDF Full-text (127 KB) | HTML Full-text | XML Full-text
Abstract
Two new groups of cholane-peptoid hybrid macrocycles were produced by implementing novel combinations of the MiB methodology. Steroid-based hybrid macrolactams including heterocycle and aryl moieties were obtained by utilizing cholanic dicarboxylic acids and diamines in a bidirectional double Ugi-Four-Component (Ugi-4CR) based macrocyclization [...] Read more.
Two new groups of cholane-peptoid hybrid macrocycles were produced by implementing novel combinations of the MiB methodology. Steroid-based hybrid macrolactams including heterocycle and aryl moieties were obtained by utilizing cholanic dicarboxylic acids and diamines in a bidirectional double Ugi-Four-Component (Ugi-4CR) based macrocyclization protocol. Alternatively, N-substituted cyclocholamides were produced from a cholanic pseudo-amino acid by an Ugi-4CR-based cyclooligomerization approach. Both types of macrocycles are steroid-peptoid hybrid macrocycles containing exocyclic peptidic chains. These novel frameworks are a result of the use of bile acids bifunctionalized with carboxylic and amino functionalities as bifunctional building blocks of the Ugi-MiB approach. Full article
(This article belongs to the Special Issue Bile Acids)
Open AccessArticle Synthesis and In-vitro Antitumor Activity of 1-[3-(Indol-1-yl)prop-1-yn-1-yl]phthalazines and Related Compounds
Molecules 2007, 12(8), 1900-1909; doi:10.3390/12081900
Received: 2 August 2007 / Revised: 14 August 2007 / Accepted: 14 August 2007 / Published: 17 August 2007
Cited by 14 | PDF Full-text (85 KB) | HTML Full-text | XML Full-text
Abstract A series of novel 3-(indol-1-yl)prop-1-yn-1-yl-substituted phthalazines and related azines was prepared via a concise pathway by palladium-catalyzed cross-coupling of appropriate halo-azines and N-propargylindoles. Some of the compounds exhibited significant antitumor activity in an in-vitro assay. Full article
Open AccessArticle Palladate Salts from Chiral Pyridinium Ionic Liquids: Synthesis and Crystal Structures
Molecules 2007, 12(8), 1940-1949; doi:10.3390/12081940
Received: 23 May 2007 / Revised: 19 July 2007 / Accepted: 19 July 2007 / Published: 20 August 2007
Cited by 8 | PDF Full-text (154 KB) | HTML Full-text | XML Full-text
Abstract This paper reports the preparation, characterization and the crystal X-ray structures of metal-containing ionic liquid complexes based on chiral pyridinium cations and tetrachloropalladate (II) [PdCl4]2-. Full article
(This article belongs to the Special Issue Heterocycles)
Open AccessArticle Antioxidant Capacity and In Vitro Prevention of Dental Plaque Formation by Extracts and Condensed Tannins of Paullinia cupana
Molecules 2007, 12(8), 1950-1963; doi:10.3390/12081950
Received: 28 May 2007 / Revised: 1 August 2007 / Accepted: 1 August 2007 / Published: 20 August 2007
Cited by 39 | PDF Full-text (116 KB) | HTML Full-text | XML Full-text
Abstract
Chemical evaluation of the semi-purified fraction from the seeds of guaraná, Paullinia cupana H.B.K. var. sorbilis (Mart.) Ducke, yielded the following compounds: caffeine, catechin, epicatechin, ent-epicatechin, and procyanidins B1, B2, B3, B4, A2 [...] Read more.
Chemical evaluation of the semi-purified fraction from the seeds of guaraná, Paullinia cupana H.B.K. var. sorbilis (Mart.) Ducke, yielded the following compounds: caffeine, catechin, epicatechin, ent-epicatechin, and procyanidins B1, B2, B3, B4, A2, and C1. Measurement of the antioxidant activity by reduction of the DPPH radical confirmed the anti-radical properties of the aqueous (AqE) and crude (EBPC) extracts and semi-purified (EPA and EPB) fractions. The EPA fraction showed radical-scavenging activity (RSA) and protected DPPH from discoloration at 5.23±0.08 (RSD%=1.49) μg/mL, and for the phosphomolybdenum complex showed a higher Relative Antioxidant Capacity (RAC) at 0.75±0.01 (1.75). The EPA fraction had a total polyphenolics content of 65.80%±0.62 (RSD%=0.93). The plant drug showed 5.47% ± 0.19 (RSD%=3.51) and 6.19% ± 0.08 (RSD%=1.29) for total polyphenolics and methylxanthines, respectively. In vitro assessment of the antibacterial potential of the Paullinia cupana extracts against Streptococcus mutans showed that these could be used in the prevention of bacterial dental plaque. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessCommunication Targeted Synthesis of 1-(4-Hydroxyiminomethylpyridinium)-3-pyridiniumpropane Dibromide – A New Nerve Agent Reactivator
Molecules 2007, 12(8), 1964-1972; doi:10.3390/12081964
Received: 31 July 2007 / Revised: 14 August 2007 / Accepted: 14 August 2007 / Published: 20 August 2007
Cited by 14 | PDF Full-text (64 KB) | HTML Full-text | XML Full-text
Abstract
Preparation of 1-(4-hydroxy-iminomethylpyridinium)-3-pyridiniumpropane dibromide is described. This compound represents a new acetylcholinesterase (AChE) reactivator, which has no substituents on the second pyridinium ring as found in other commonly used AChE reactivators. The reactivation ability of this reactivator was tested on tabun- and [...] Read more.
Preparation of 1-(4-hydroxy-iminomethylpyridinium)-3-pyridiniumpropane dibromide is described. This compound represents a new acetylcholinesterase (AChE) reactivator, which has no substituents on the second pyridinium ring as found in other commonly used AChE reactivators. The reactivation ability of this reactivator was tested on tabun- and cyclosarin-inhibited AChE. According to the results obtained, the new compound (without substitution and with decreased molecule size) showed increased reactivation potency in case of cyclosarin inhibited AChE. A potent oxime for treatment of tabun and cyclosarin-caused intoxications was thus obtained via slight modification of the reactivator structure (compared to trimedoxime and K027). Full article
Open AccessArticle Synthesis of Novel Derivatives of 4-Amino-3-(2-Furyl)-5-Mercapto-1,2,4-Triazole as Potential HIV-1 NNRTIs
Molecules 2007, 12(8), 2003-2016; doi:10.3390/12082003
Received: 21 July 2007 / Revised: 17 August 2007 / Accepted: 20 August 2007 / Published: 22 August 2007
Cited by 30 | PDF Full-text (104 KB) | HTML Full-text | XML Full-text
Abstract
A series of 5-alkylthio (2a-d), 4-arylideneamino (3a-d) and 4-arylideneamino- 5-alkylthio derivatives (4a-f) of 4-amino-3-(2-furyl)-5-mercapto-1,2,4-triazole (1) were synthesized by alkylation of the parent compound with alkyl halides and condensation with aldehydes, respectively. Sulfanyl dimers 5a-d and 4-iminomethyl dimer 6 were correspondingly prepared by [...] Read more.
A series of 5-alkylthio (2a-d), 4-arylideneamino (3a-d) and 4-arylideneamino- 5-alkylthio derivatives (4a-f) of 4-amino-3-(2-furyl)-5-mercapto-1,2,4-triazole (1) were synthesized by alkylation of the parent compound with alkyl halides and condensation with aldehydes, respectively. Sulfanyl dimers 5a-d and 4-iminomethyl dimer 6 were correspondingly prepared by reaction with alkane dibromides and 1,4-diformylbenzene. Mannich base 7 was also synthesized by aminomethylation of the 3-sulfanyltriazole 1 at the N1 position. The newly designed and synthesized substituted s-triazole derivatives were assayed for anti-HIV-1 activity by examination of their inhibition of HIV-1-induced cytopathogenicity in MT-4 cells and by determination of their inhibitory effect on HIV-1 reverse transcriptase. Compound 4e was found to be the most active inhibitor against HIV- 1 replication in cell culture (EC50 = 12 μM) and against HIV-1 reverse transcriptase (IC50 = 43.5 μM), which provided a good lead for further optimization. Full article
Open AccessArticle An Improved Synthesis of 4-Chlorocoumarin-3-sulfonyl Chloride and Its Reactions with Different Bidentate Nucleophiles to Give Pyrido[1',2':2,3]- and Thiazino[3',2':2,3]-1,2,4-Thiadiazino[6,5-c]Benzopyran-6-one 7,7-Dioxides
Molecules 2007, 12(8), 2017-2028; doi:10.3390/12082017
Received: 3 June 2007 / Revised: 8 August 2007 / Accepted: 8 August 2007 / Published: 22 August 2007
Cited by 4 | PDF Full-text (86 KB) | HTML Full-text | XML Full-text
Abstract
An improved synthetic method affording 4-chlorocoumarin-3-sulfonyl chloride (4) in very good yield (ca. 85 %) is reported. This compound was reacted with various bidentate nucleophiles such as 2-aminopyridines and 2-aminothiazoles in order to obtain substituted pyrido- and thiazino-1,2,4-thiadiazino-benzopyranone dioxides (potential anticancer and [...] Read more.
An improved synthetic method affording 4-chlorocoumarin-3-sulfonyl chloride (4) in very good yield (ca. 85 %) is reported. This compound was reacted with various bidentate nucleophiles such as 2-aminopyridines and 2-aminothiazoles in order to obtain substituted pyrido- and thiazino-1,2,4-thiadiazino-benzopyranone dioxides (potential anticancer and anti-HIV agents). These reactions occurred rapidly at room temperature giving yellowish precipitates, which are insoluble in common organic solvents, making the purification process challenging. Further investigation has shown that these fused heterocycles are not stable and decompose with opening of the 1,2,4-thiadiazine ring. Full article
Open AccessArticle New Polyhydroxylated Furostanol Saponins with Inhibitory Action against NO Production from Tupistra chinensis Rhizomes
Molecules 2007, 12(8), 2029-2037; doi:10.3390/12082029
Received: 8 June 2007 / Revised: 11 July 2007 / Accepted: 12 July 2007 / Published: 23 August 2007
Cited by 15 | PDF Full-text (145 KB) | HTML Full-text | XML Full-text
Abstract
Two furostanol saponins were obtained from the rhizomes of Tupistra chinensis Bak. Their structures were determined as 5β-furost-δ25(27)-en-1β,2β,3β,4β,5β,7α,22ξ,26- octaol-6-one-26-O-β-D-glucopyranoside (1) and 5β-furost-δ25(27)-en-1β,2β,3β,4β,5β,6β, 7α,22ξ,26-nonaol-26-O-β-D-glucopyranoside (2), on the basis of chemical and spectroscopic evidence. Both compounds displayed marked inhibitory action [...] Read more.
Two furostanol saponins were obtained from the rhizomes of Tupistra chinensis Bak. Their structures were determined as 5β-furost-δ25(27)-en-1β,2β,3β,4β,5β,7α,22ξ,26- octaol-6-one-26-O-β-D-glucopyranoside (1) and 5β-furost-δ25(27)-en-1β,2β,3β,4β,5β,6β, 7α,22ξ,26-nonaol-26-O-β-D-glucopyranoside (2), on the basis of chemical and spectroscopic evidence. Both compounds displayed marked inhibitory action against NO production in rat abdomen macrophages induced by lipopolysaccharide (LPS) at 40 μg/mL. Full article
Open AccessArticle Two Novel Lanostane Triterpenoids from Ganoderma Sinense
Molecules 2007, 12(8), 2038-2046; doi:10.3390/12082038
Received: 17 May 2007 / Revised: 20 August 2007 / Accepted: 20 August 2007 / Published: 23 August 2007
Cited by 20 | PDF Full-text (142 KB) | HTML Full-text | XML Full-text
Abstract
Two novel lanostane-type triterpenes, Ganolactone B and Ganoderiol A triacetate, were isolated from the fruiting bodies of G. sinense, together with six known compounds. The structures of the two new triterpenes were determined as 3β,7β- dihydroxy-11,15-dioxo-lanosta-8-en-24→20 lactone [...] Read more.
Two novel lanostane-type triterpenes, Ganolactone B and Ganoderiol A triacetate, were isolated from the fruiting bodies of G. sinense, together with six known compounds. The structures of the two new triterpenes were determined as 3β,7β- dihydroxy-11,15-dioxo-lanosta-8-en-24→20 lactone (1) and 3β,24,26-triacetoxy-5α-lanosta-7,9(11)-dien-25-ol (2), respectively, by chemical and spectroscopic means. Full article
Open AccessArticle Antibacterial Effect of Five Zingiberaceae Essential Oils
Molecules 2007, 12(8), 2047-2060; doi:10.3390/12082047
Received: 1 August 2007 / Revised: 20 August 2007 / Accepted: 22 August 2006 / Published: 23 August 2007
Cited by 33 | PDF Full-text (256 KB) | HTML Full-text | XML Full-textRetraction
Abstract
Essential oil obtained by hydrodistillation and two different solvent extractions (petroleum ether and ethanol) from five Zingiberaceae species: ginger (Zingiber officinale Roscoe.), galanga (Alpinia galanga Sw.), turmeric (Curcuma longa L.), kaempferia (Boesenbergia pandurata Holtt.) and bastard cardamom ( [...] Read more.
Essential oil obtained by hydrodistillation and two different solvent extractions (petroleum ether and ethanol) from five Zingiberaceae species: ginger (Zingiber officinale Roscoe.), galanga (Alpinia galanga Sw.), turmeric (Curcuma longa L.), kaempferia (Boesenbergia pandurata Holtt.) and bastard cardamom (Amomum xanthioides Wall.) was characterized. Volatile components of all extracts were analyzed by gas chromatographymass spectrometry (GC-MS). The major components of ginger, turmeric, galangal, bastard cardamom and kaempferia were zingiberene, turmerone, methyl chavicol, and γ-terpinene, respectively. Their antibacterial effects towards Escherichia coli, Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes were tested by a disc diffusion assay. Essential oil of kaempferia and bastard cardamom obtained by hydrodistillation extraction could inhibit growth of all tested bacteria. Essential oil of ginger extracted by hydrodistillation had the highest efficiency against three positive strains of bacteria (S. aureus, B. cereus and L. monocytogenes), with a minimum concentration to inhibit B. cereus and L. monocytogenes of 6.25 mg/mL. Full article
Open AccessArticle Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate
Molecules 2007, 12(8), 2061-2079; doi:10.3390/12082061
Received: 16 February 2007 / Revised: 26 May 2007 / Accepted: 1 June 2007 / Published: 24 August 2007
Cited by 20 | PDF Full-text (135 KB) | HTML Full-text | XML Full-text
Abstract
The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA) afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo [...] Read more.
The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA) afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction of 6a,b,d-f,h with glycine and hippuric acid in acetic anhydride afforded pyridazinone derivatives 17a-f. Synthesis of pyridazine carboxylic acid derivatives 22a,b from the reaction of 6b,e with dimethyl acetylenedicarboxylate (DMAD) in the presence of triphenylphosphine at room temperature is also reported. Most of these reactions were conducted under irradiation in a microwave oven in the absence of solvent in an attempt to improve the product yields and to reduce the reaction times. Full article
Open AccessArticle Ultrasound Assisted Synthesis of 5,9-Dimethylpentadecane and 5,9-Dimethylhexadecane – the Sex Pheromones of Leucoptera coffeella
Molecules 2007, 12(8), 2080-2088; doi:10.3390/12082080
Received: 8 August 2007 / Revised: 23 August 2007 / Accepted: 23 August 2007 / Published: 28 August 2007
Cited by 8 | PDF Full-text (70 KB) | HTML Full-text | XML Full-text
Abstract
Racemic 5,9-dimethylpentadecane and 5,9-dimethylhexadecane, the major and minor constituents, respectively, of the sex pheromone of Leucoptera coffeella, have been synthesized from citronellol in 56-58% overall yield through six steps. Ultrasound irradiation efficiently supported tosylation of alcohols (two steps) as well as [...] Read more.
Racemic 5,9-dimethylpentadecane and 5,9-dimethylhexadecane, the major and minor constituents, respectively, of the sex pheromone of Leucoptera coffeella, have been synthesized from citronellol in 56-58% overall yield through six steps. Ultrasound irradiation efficiently supported tosylation of alcohols (two steps) as well as the subsequent cross coupling reactions with the pertinent Grignard reagents (also two steps). Full article

Review

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Open AccessReview Functional Analysis of Polyphenol Oxidases by Antisense/Sense Technology
Molecules 2007, 12(8), 1569-1595; doi:10.3390/12081569
Received: 30 May 2007 / Revised: 19 July 2007 / Accepted: 19 July 2007 / Published: 27 July 2007
Cited by 61 | PDF Full-text (391 KB) | HTML Full-text | XML Full-text
Abstract
Polyphenol oxidases (PPOs) catalyze the oxidation of phenolics to quinones, the secondary reactions of which lead to oxidative browning and postharvest losses of many fruits and vegetables. PPOs are ubiquitous in angiosperms, are inducible by both biotic and abiotic stresses, and have [...] Read more.
Polyphenol oxidases (PPOs) catalyze the oxidation of phenolics to quinones, the secondary reactions of which lead to oxidative browning and postharvest losses of many fruits and vegetables. PPOs are ubiquitous in angiosperms, are inducible by both biotic and abiotic stresses, and have been implicated in several physiological processes including plant defense against pathogens and insects, the Mehler reaction, photoreduction of molecular oxygen by PSI, regulation of plastidic oxygen levels, aurone biosynthesis and the phenylpropanoid pathway. Here we review experiments in which the roles of PPO in disease and insect resistance as well as in the Mehler reaction were investigated using transgenic tomato (Lycopersicon esculentum) plants with modified PPO expression levels (suppressed PPO and overexpressing PPO). These transgenic plants showed normal growth, development and reproduction under laboratory, growth chamber and greenhouse conditions. Antisense PPO expression dramatically increased susceptibility while PPO overexpression increased resistance of tomato plants to Pseudomonas syringae. Similarly, PPO-overexpressing transgenic plants showed an increase in resistance to various insects, including common cutworm (Spodoptera litura (F.)), cotton bollworm (Helicoverpa armigera (Hübner)) and beet army worm (Spodoptera exigua (Hübner)), whereas larvae feeding on plants with suppressed PPO activity had higher larval growth rates and consumed more foliage. Similar increases in weight gain, foliage consumption, and survival were also observed with Colorado potato beetles (Leptinotarsa decemlineata (Say)) feeding on antisense PPO transgenic tomatoes. The putative defensive mechanisms conferred by PPO and its interaction with other defense proteins are discussed. In addition, transgenic plants with suppressed PPO exhibited more favorable water relations and decreased photoinhibition compared to nontransformed controls and transgenic plants overexpressing PPO, suggesting that PPO may have a role in the development of plant water stress and potential for photoinhibition and photooxidative damage that may be unrelated to any effects on the Mehler reaction. These results substantiate the defensive role of PPO and suggest that manipulation of PPO activity in specific tissues has the potential to provide broad-spectrum resistance simultaneously to both disease and insect pests, however, effects of PPO on postharvest quality as well as water stress physiology should also be considered. In addition to the functional analysis of tomato PPO, the application of antisense/sense technology to decipher the functions of PPO in other plant species as well as for commercial uses are discussed. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessReview Flavonoid Composition of Citrus Juices
Molecules 2007, 12(8), 1641-1673; doi:10.3390/12081641
Received: 22 June 2007 / Revised: 30 July 2006 / Accepted: 31 July 2007 / Published: 3 August 2007
Cited by 183 | PDF Full-text (369 KB) | HTML Full-text | XML Full-text
Abstract
In the early nineties the presence of flavonoids in Citrus juices began to attract the attention of a number of researchers, as a result of their biological and physiological importance. This short review will explore two different aspects. The first part will [...] Read more.
In the early nineties the presence of flavonoids in Citrus juices began to attract the attention of a number of researchers, as a result of their biological and physiological importance. This short review will explore two different aspects. The first part will focus on analytical techniques for the characterization of juices from different Citrus fruits regarding their flavonoid content (even if present in only trace amounts), concentrating on the most widely used methods (LC-MS and LC-MS-MS). The second part analyzes data reported in the literature regarding the composition of Citrus juices. The main components that have been detected so far are flavanone-O-glycosides and flavone-O- or -C-glycosides. The presence of such derivatives in various hand-squeezed and industrial juices is discussed, with special emphasis on their correlation to different species. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessReview Phenolic Molecules in Virgin Olive Oils: a Survey of Their Sensory Properties, Health Effects, Antioxidant Activity and Analytical Methods. An Overview of the Last Decade Alessandra
Molecules 2007, 12(8), 1679-1719; doi:10.3390/12081679
Received: 9 June 2007 / Revised: 2 August 2007 / Accepted: 2 August 2006 / Published: 6 August 2007
Cited by 320 | PDF Full-text (262 KB) | HTML Full-text | XML Full-text
Abstract
Among vegetable oils, virgin olive oil (VOO) has nutritional and sensory characteristics that to make it unique and a basic component of the Mediterranean diet. The importance of VOO is mainly attributed both to its high content of oleic acid a balanced [...] Read more.
Among vegetable oils, virgin olive oil (VOO) has nutritional and sensory characteristics that to make it unique and a basic component of the Mediterranean diet. The importance of VOO is mainly attributed both to its high content of oleic acid a balanced contribution quantity of polyunsaturated fatty acids and its richness in phenolic compounds, which act as natural antioxidants and may contribute to the prevention of several human diseases. The polar phenolic compounds of VOO belong to different classes: phenolic acids, phenyl ethyl alcohols, hydroxy-isochromans, flavonoids, lignans and secoiridoids. This latter family of compounds is characteristic of Oleaceae plants and secoiridoids are the main compounds of the phenolic fraction. Many agronomical and technological factors can affect the presence of phenols in VOO. Its shelf life is higher than other vegetable oils, mainly due to the presence of phenolic molecules having a catechol group, such as hydroxytyrosol and its secoiridoid derivatives. Several assays have been used to establish the antioxidant activity of these isolated phenolic compounds. Typical sensory gustative properties of VOO, such as bitterness and pungency, have been attributed to secoiridoid molecules. Considering the importance of the phenolic fraction of VOO, high performance analytical methods have been developed to characterize its complex phenolic pattern. The aim of this review is to realize a survey on phenolic compounds of virgin olive oils bearing in mind their chemical-analytical, healthy and sensory aspects. In particular, starting from the basic studies, the results of researches developed in the last ten years will be focused. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessReview Supra-molecular Association and Polymorphic Behaviour In Systems Containing Bile Acid Salts
Molecules 2007, 12(8), 1731-1754; doi:10.3390/12081731
Received: 9 May 2007 / Revised: 12 July 2007 / Accepted: 12 July 2007 / Published: 7 August 2007
Cited by 42 | PDF Full-text (467 KB) | HTML Full-text | XML Full-text
Abstract
A wide number of supra-molecular association modes are observed in mixtures containing water and bile salts, BS, (with, eventually, other components). Molecular or micellar solutions transform into hydrated solids, fibres, lyotropic liquid crystals and/or gels by raising the concentration, the temperature, adding [...] Read more.
A wide number of supra-molecular association modes are observed in mixtures containing water and bile salts, BS, (with, eventually, other components). Molecular or micellar solutions transform into hydrated solids, fibres, lyotropic liquid crystals and/or gels by raising the concentration, the temperature, adding electrolytes, surfactants, lipids and proteins. Amorphous or ordered phases may be formed accordingly. The forces responsible for this very rich polymorphism presumably arise from the unusual combination of electrostatic, hydrophobic and hydrogen-bond contributions to the system stability, with subsequent control of the supra-molecular organisation modes. The stabilising effect due to hydrogen bonds does not occur in almost all surfactants or lipids and is peculiar to bile acids and salts. Some supra-molecular organisation modes, supposed to be related to malfunctions and dis-metabolic diseases in vivo, are briefly reported and discussed. Full article
(This article belongs to the Special Issue Bile Acids)
Open AccessReview Synthetic Approaches to Heterocyclic Ligands for Gd-Based MRI Contrast Agents
Molecules 2007, 12(8), 1771-1795; doi:10.3390/12081771
Received: 29 May 2007 / Revised: 3 August 2007 / Accepted: 3 August 2007 / Published: 9 August 2007
Cited by 5 | PDF Full-text (184 KB) | HTML Full-text | XML Full-text
Abstract
Magnetic Resonance Imaging (MRI) methods are currently used in the clinic for the non invasive detection and characterization of a wide variety of pathologies. Increases in the diagnostic efficiency of MRI have been helped by both the design of dedicated MR sequences [...] Read more.
Magnetic Resonance Imaging (MRI) methods are currently used in the clinic for the non invasive detection and characterization of a wide variety of pathologies. Increases in the diagnostic efficiency of MRI have been helped by both the design of dedicated MR sequences revealing specific aspects of the pathology and by the development of more sensitive and selective Contrast Agents (CAs), capable of more precisely delineating the borderline regions. In the present review we focus on the synthetic strategies used to obtain MRI CAs containing heterocyclic rings. Full article
Open AccessReview Exploitation of Bile Acid Transport Systems in Prodrug Design
Molecules 2007, 12(8), 1859-1889; doi:10.3390/12081859
Received: 6 June 2007 / Revised: 13 August 2007 / Accepted: 14 August 2007 / Published: 16 August 2007
Cited by 62 | PDF Full-text (168 KB) | HTML Full-text | XML Full-text
Abstract
The enterohepatic circulation of bile acids is one of the most efficient recycling routes in the human body. It is a complex process involving numerous transport proteins, which serve to transport bile acids from the small intestine into portal circulation, from the [...] Read more.
The enterohepatic circulation of bile acids is one of the most efficient recycling routes in the human body. It is a complex process involving numerous transport proteins, which serve to transport bile acids from the small intestine into portal circulation, from the portal circulation into the hepatocyte, from the hepatocyte into the bile, and from the gall bladder to the small intestine. The tremendous transport capacity and organ specificity of enterohepatic circulation combined with versatile derivatization possibilities, rigid steroidal backbone, enantiomeric purity, availability, and low cost have made bile acids attractive tools in designing pharmacological hybrid molecules and prodrugs with the view of improving intestinal absorption, increasing the metabolic stability of pharmaceuticals, specifically targeting drugs to organs involved in enterohepatic circulation, as well as sustaining therapeutically reasonable systemic concentrations of active agents. This article briefly describes bile acid transport proteins involved in enterohepatic circulation, summarizes the key factors affecting on the transport by these proteins, and reviews the use of bile acids and their derivatives in designing prodrugs capable of exploiting the bile acid transport system. Full article
(This article belongs to the Special Issue Bile Acids)
Open AccessReview Biological Activities of Hydrazone Derivatives
Molecules 2007, 12(8), 1910-1939; doi:10.3390/12081910
Received: 13 March 2007 / Revised: 11 August 2007 / Accepted: 16 August 2007 / Published: 17 August 2007
Cited by 409 | PDF Full-text (194 KB) | HTML Full-text | XML Full-text
Abstract
There has been considerable interest in the development of novel compounds with anticonvulsant, antidepressant, analgesic, antiinflammatory, antiplatelet, antimalarial, antimicrobial, antimycobacterial, antitumoral, vasodilator, antiviral and antischistosomiasis activities. Hydrazones possessing an azometine -NHN=CH- proton constitute an important class of compounds for new drug development. [...] Read more.
There has been considerable interest in the development of novel compounds with anticonvulsant, antidepressant, analgesic, antiinflammatory, antiplatelet, antimalarial, antimicrobial, antimycobacterial, antitumoral, vasodilator, antiviral and antischistosomiasis activities. Hydrazones possessing an azometine -NHN=CH- proton constitute an important class of compounds for new drug development. Therefore, many researchers have synthesized these compounds as target structures and evaluated their biological activities. These observations have been guiding for the development of new hydrazones that possess varied biological activities. Full article
Open AccessReview Supramolecular Chirality in Crystalline Assemblies of Bile Acids and Their Derivatives; Three-Axial, Tilt, Helical, and Bundle Chirality
Molecules 2007, 12(8), 1973-2000; doi:10.3390/12081973
Received: 30 June 2007 / Revised: 20 August 2007 / Accepted: 20 August 2007 / Published: 22 August 2007
Cited by 27 | PDF Full-text (1189 KB) | HTML Full-text | XML Full-text
Abstract
Steroidal bile acids and their derivatives exhibit characteristic inclusion behaviors in the crystalline state. Their crystals present varied assemblies due to asymmetric molecular structures, which relate to supramolecular properties through cooperative weak interactions. An overview indicates that the steroidal assemblies lie in [...] Read more.
Steroidal bile acids and their derivatives exhibit characteristic inclusion behaviors in the crystalline state. Their crystals present varied assemblies due to asymmetric molecular structures, which relate to supramolecular properties through cooperative weak interactions. An overview indicates that the steroidal assemblies lie in an intermediate position among various molecules and have hierarchical structures such as primary, secondary, tertiary, and host-guest assemblies like proteins. Such an interpretation brought about the idea that the assemblies with dimensionality present supramolecular chirality such as three-axial, tilt, helical, bundle, and complementary chirality. This concept of the supramolecular chirality enables us to understand formation of chiral crystals starting from the molecular chirality of the steroidal molecules. Full article
(This article belongs to the Special Issue Bile Acids)

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