Molecules

332 KiB

Open AccessReview

Sonoelectrochemical Synthesis of Nanoparticles

by Veronica Sáez and Timothy J. Mason

Molecules 2009, 14(10), 4284-4299; https://doi.org/10.3390/molecules14104284 - 23 Oct 2009

Cited by 171 | Viewed by 18059

This article reviews the nanomaterials that have been prepared to date by pulsed sonoelectrochemistry. The majority of nanomaterials produced by this method are pure metals such as silver, palladium, platinum, zinc, nickel and gold, but more recently the syntheses have been extended to [...] Read more.

This article reviews the nanomaterials that have been prepared to date by pulsed sonoelectrochemistry. The majority of nanomaterials produced by this method are pure metals such as silver, palladium, platinum, zinc, nickel and gold, but more recently the syntheses have been extended to include the preparation of nanosized metallic alloys and metal oxide semiconductors. A major advantage of this methodology is that the shape andsize of the nanoparticles can be adjusted by varying the operating parameters which include ultrasonic power, current density, deposition potential and the ultrasonic vs electrochemical pulse times. Together with these, it is also possible to adjust the pH, temperature and composition of the electrolyte in the sonoelectrochemistry cell. Full article

(This article belongs to the Special Issue Sonochemistry-organic synthesis)

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Graphical abstract

192 KiB

Open AccessCommunication

Preparation of (S)-1-Halo-2-octanols Using Ionic Liquids and Biocatalysts

by Mireia Oromí-Farrús, Jordi Eras, Núria Sala, Mercè Torres and Ramon Canela

Molecules 2009, 14(10), 4275-4283; https://doi.org/10.3390/molecules14104275 - 23 Oct 2009

Cited by 7 | Viewed by 9538

Abstract

Preparation of (S)-1-chloro-2-octanol and (S)-1-bromo-2-octanol was carried out by the enzymatic hydrolysis of halohydrin palmitates using biocatalysts. Halohydrin palmitates were prepared by various methods from palmitic acid and 1,2-octanediol. A tandem hydrolysis was carried out using lipases from Candida [...] Read more.

Preparation of (S)-1-chloro-2-octanol and (S)-1-bromo-2-octanol was carried out by the enzymatic hydrolysis of halohydrin palmitates using biocatalysts. Halohydrin palmitates were prepared by various methods from palmitic acid and 1,2-octanediol. A tandem hydrolysis was carried out using lipases from Candida antarctica (Novozym^® 435), Rhizomucor miehei (Lipozyme IM), and “resting cells” from a Rhizopus oryzae strain that was not mycotoxigenic. The influence of the enzyme and the reaction medium on the selective hydrolysis of isomeric mixtures of halohydrin esters is described. Novozym^®435 allowed preparation of (S)-1-chloro-2-octanol and (S)-1-bromo-2-octanol after 1–3 h of reaction at 40 °C in [BMIM][PF₆]. Full article

(This article belongs to the Collection Ionic Liquids)

330 KiB

Open AccessArticle

An Unsymmetrical Tetrathiafulvalene with a Fused 1,2,5-Thiadiazole Ring and Methylthio Groups

by Masaaki Tomura and Yoshiro Yamashita

Molecules 2009, 14(10), 4266-4274; https://doi.org/10.3390/molecules14104266 - 23 Oct 2009

Cited by 1 | Viewed by 7718

Abstract

The title compound, 5-(4,5-dimethylthio-1,3-dithiol-2-ylidene)-1,3-diaza-2,4,6-trithiapentalene (4,5-dimethylthio [1,2,5]thiadiazolotetrathiafulvalene, molecular formula C₈H₆N₂S₇) crystallizes in the P2₁/n space group with one molecule in the asymmetric unit. The molecular framework is planar within 0.19 Å. The molecules [...] Read more.

The title compound, 5-(4,5-dimethylthio-1,3-dithiol-2-ylidene)-1,3-diaza-2,4,6-trithiapentalene (4,5-dimethylthio [1,2,5]thiadiazolotetrathiafulvalene, molecular formula C₈H₆N₂S₇) crystallizes in the P2₁/n space group with one molecule in the asymmetric unit. The molecular framework is planar within 0.19 Å. The molecules form a head-to-tail type of π-stacking dimer with an interplanar distance is 3.50(1) Å, where methylthio groups face away from each other. The molecules are also linked by weak intermolecular S···S heteroatom interactions [3.497(1) and 3.572(1) Å] to construct a unique one-dimensional molecular tape structure. Full article

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Graphical abstract

194 KiB

Open AccessArticle

Investigating Biological Activity Spectrum for Novel Styrylquinazoline Analogues

by Josef Jampilek, Robert Musiol, Jacek Finster, Matus Pesko, James Carroll, Katarina Kralova, Marcela Vejsova, Jim O'Mahony, Aidan Coffey, Jiri Dohnal and Jaroslaw Polanski

Molecules 2009, 14(10), 4246-4265; https://doi.org/10.3390/molecules14104246 - 23 Oct 2009

Cited by 60 | Viewed by 12244

Abstract

In this study, series of ring-substituted 2-styrylquinazolin-4(3H)-one and 4-chloro-2-styrylquinazoline derivatives were prepared. The syntheses of the discussed compounds are presented. The compounds were analyzed by RP-HPLC to determine lipophilicity. They were tested for their inhibitory activity on photosynthetic electron transport (PET) [...] Read more.

In this study, series of ring-substituted 2-styrylquinazolin-4(3H)-one and 4-chloro-2-styrylquinazoline derivatives were prepared. The syntheses of the discussed compounds are presented. The compounds were analyzed by RP-HPLC to determine lipophilicity. They were tested for their inhibitory activity on photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial strains and against eight fungal strains. Several compounds showed biological activity comparable with or higher than that of the standard isoniazid. It was found that the electronic properties of the R substituent, and not the total lipophilicity of the compound, were decisive for the photosynthesis-inhibiting activity of tested compounds. Full article

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139 KiB

Open AccessArticle

Soft Alkyl Ether Prodrugs of a Model Phenolic Drug: The Effect of Incorporation of Ethyleneoxy Groups on Transdermal Delivery

by Joshua Denver Thomas, Susruta Majumdar and Kenneth Berry Sloan

Molecules 2009, 14(10), 4231-4245; https://doi.org/10.3390/molecules14104231 - 22 Oct 2009

Cited by 15 | Viewed by 15777

Abstract

Two different types of soft alkyl ether prodrugs incorporating ethyleneoxy groups into the promoiety have been synthesized for a model phenol (acetaminophen, APAP): alkyloxycarbonyloxymethyl type (AOCOM) and N-alkyl-N-alkyloxycarbonyl-aminomethyl type (NANAOCAM). The solubilities in isopropyl myristate, S_IPM, and water, [...] Read more.

Two different types of soft alkyl ether prodrugs incorporating ethyleneoxy groups into the promoiety have been synthesized for a model phenol (acetaminophen, APAP): alkyloxycarbonyloxymethyl type (AOCOM) and N-alkyl-N-alkyloxycarbonyl-aminomethyl type (NANAOCAM). The solubilities in isopropyl myristate, S_IPM, and water, S_AQ, partition coefficients between IPM and pH 4.0 buffer, K_IPM:4.0, and the delivery of total species containing APAP through hairless mouse skin from IPM, J_MMIPM, have been measured for the prodrugs. The J_MMIPM values were accurately predicted by the Roberts-Sloan (RS) equation. Only modest increases in JMMIPM were realized (about 1.4 times) by each type. The only prodrug that was more water soluble and more lipid soluble than APAP did not improve J_MMIPM of APAP. This result may be due to the strong association of water molecules with the ethyleneoxy groups, and especially the triethyleneoxy derivative, which dramatically increases the molecular weight and depresses J_MMIPM. Full article

(This article belongs to the Special Issue Prodrugs)

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481 KiB

Open AccessArticle

Chemical Composition and in Vitro Antimicrobial and Mutagenic Activities of Seven Lamiaceae Essential Oils

by Laura De Martino, Vincenzo De Feo and Filomena Nazzaro

Molecules 2009, 14(10), 4213-4230; https://doi.org/10.3390/molecules14104213 - 20 Oct 2009

Cited by 139 | Viewed by 14763

Abstract

Deeper knowledge of the potentiality of aromatic plants can provide results of economic importance for food and pharmacological industry. The essential oils of seven Lamiaceae species were analyzed by gas chromatography-mass spectrometry and assayed for their antibacterial, antifungal and mutagenic activities. Monoterpenes in [...] Read more.

Deeper knowledge of the potentiality of aromatic plants can provide results of economic importance for food and pharmacological industry. The essential oils of seven Lamiaceae species were analyzed by gas chromatography-mass spectrometry and assayed for their antibacterial, antifungal and mutagenic activities. Monoterpenes in the oils ranged between 82.47% (hyssop oil) and 97.48% (thyme oil), being mainly represented by oxygenated compounds. The antibacterial activity was evaluated against six pathogenic and five non-pathogenic bacterial strains. Oregano and thyme oils showed the strongest antibacterial activity against the pathogenic ones. The antifungal activity was evaluated against six fungal strains of agrifood interest: the oils tested exhibited variable degrees of activity. Two Salmonella typhimurium strains were used to assess the possible mutagenic activity. No oil showed mutagenic activity. Data obtained let us hypothesise that the use of essential oils could be a viable and safe way to decrease the utilisation of synthetic food preservatives. Further research is needed to obtain information regarding the practical effectiveness of essential oils to prevent the growth of food borne and spoiling microbes under specific application conditions. Full article

270 KiB

Open AccessArticle

Rhodanineacetic Acid Derivatives as Potential Drugs: Preparation, Hydrophobic Properties and Antifungal Activity of (5-Arylalkylidene-4-oxo-2-thioxo-1,3-thiazolidin-3-yl)acetic Acids

by Jan Dolezel, Petra Hirsova, Veronika Opletalova, Jiri Dohnal, Vejsova Marcela, Jiri Kunes and Josef Jampilek

Molecules 2009, 14(10), 4197-4212; https://doi.org/10.3390/molecules14104197 - 20 Oct 2009

Cited by 47 | Viewed by 11903

Abstract

Some [(5Z)-(5-arylalkylidene-4-oxo-2-thioxo-1,3-thiazolidin-3-yl)]acetic acids were prepared as potential antifungal compounds. The general synthetic approach to all synthesized compounds is presented. Lipophilicity of all the discussed rhodanine-3-acetic acid derivatives was analyzed using a reversed phase high performance liquid chromatography (RP-HPLC) method. The procedure [...] Read more.

Some [(5Z)-(5-arylalkylidene-4-oxo-2-thioxo-1,3-thiazolidin-3-yl)]acetic acids were prepared as potential antifungal compounds. The general synthetic approach to all synthesized compounds is presented. Lipophilicity of all the discussed rhodanine-3-acetic acid derivatives was analyzed using a reversed phase high performance liquid chromatography (RP-HPLC) method. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using an end-capped non-polar C₁₈ stationary RP column. The RP-HPLC retention parameter log k (the logarithm of the capacity factor k) is compared with log P values calculated in silico. All compounds were evaluated for antifungal effects against selected fungal species. Most compounds exhibited no interesting activity, and only {(5Z)-[4-oxo-5-(pyridin-2- ylmethylidene)-2-thioxo-1,3-thiazolidin-3-yl]}acetic acid strongly inhibited the growth of Candida tropicalis 156, Candida krusei E 28, Candida glabrata 20/I and Trichosporon asahii 1188. Full article

(This article belongs to the Special Issue ECSOC-12)

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178 KiB

Open AccessArticle

New Flavonoid Glycosides from Elsholtzia rugulosa Hemsl.

by Gaimei She, Zhiqin Guo, Haining Lv and Dongmei She

Molecules 2009, 14(10), 4190-4196; https://doi.org/10.3390/molecules14104190 - 20 Oct 2009

Cited by 34 | Viewed by 10654

Abstract

Elsholtzia rugulosa Hemsl. is known in China as a local herbal tea, medicinal herb and honey plant. Chemical examination of E. rugulosa led to the isolation of two new flavonoid glycosides, apigenin 4'-O-α-D-glucopyranoside (1) and 5,7,3',4'-tetrahydroxy-5'-C-prenylflavone-7-O-β [...] Read more.

Elsholtzia rugulosa Hemsl. is known in China as a local herbal tea, medicinal herb and honey plant. Chemical examination of E. rugulosa led to the isolation of two new flavonoid glycosides, apigenin 4'-O-α-D-glucopyranoside (1) and 5,7,3',4'-tetrahydroxy-5'-C-prenylflavone-7-O-β-D-glucopyranoside (2), together with nine known flavonoids. Their structures were elucidated on the basis of spectroscopic evidence. Full article

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458 KiB

Open AccessArticle

Substituted N-Phenylpyrazine-2-carboxamides: Synthesis and Antimycobacterial Evaluation

by Martin Doležal, Jan Zitko, Diana Kešetovičová, Jiří Kuneš and Michaela Svobodová

Molecules 2009, 14(10), 4180-4189; https://doi.org/10.3390/molecules14104180 - 20 Oct 2009

Cited by 28 | Viewed by 9312

Abstract

The condensation of chlorides of substituted pyrazinecarboxylic acids with ringsubstituted anilines yielded twelve substituted pyrazinecarboxylic acid amides. The synthetic approach, analytical, and lipophilicity data of the newly synthesized compounds are presented. Two antituberculosis assays were used. Firstly, the antimycobacterial activity against four different [...] Read more.

The condensation of chlorides of substituted pyrazinecarboxylic acids with ringsubstituted anilines yielded twelve substituted pyrazinecarboxylic acid amides. The synthetic approach, analytical, and lipophilicity data of the newly synthesized compounds are presented. Two antituberculosis assays were used. Firstly, the antimycobacterial activity against four different Mycobacterium strains in a series of pyrazine derivatives was investigated. Secondly, the antimycobacterial evaluation was performed at the Tuberculosis Antimicrobial Acquisition and Coordinating Facility (TAACF) program. Interesting in vitro antimycobacterial activity was found, N-(3-iodo-4-methylphenyl) pyrazine-2-carboxamide (9) was most active derivative compound against M. tuberculosis (MIC < 2.0 μmol/L), while another iodo derivative 5-tert-butyl-6-chloro-N-(3-iodo-4-methyl-phenyl)pyrazine-2-carboxamide (12) was the most active compound in the TAACF antituberculosis screening program (IC₉₀ = 0.819 μg/mL). Full article

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Graphical abstract

381 KiB

Open AccessArticle

Design and Synthesis of Novel 2-Phenylaminopyrimidine (PAP) Derivatives and Their Antiproliferative Effects in Human Chronic Myeloid Leukemia Cells

by Sheng Chang, Shi-Liang Yin, Jian Wang, Yong-Kui Jing and Jin-Hua Dong

Molecules 2009, 14(10), 4166-4179; https://doi.org/10.3390/molecules14104166 - 19 Oct 2009

Cited by 23 | Viewed by 13211

Abstract

A series of novel 2-phenylaminopyrimidine (PAP) derivatives structurally related to STI-571 were designed and synthesized. The abilities of these compounds to inhibit proliferation were tested in human chronic myeloid leukemia K562 cells. (E)-3-(2-bromophenyl)-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)phenyl]acrylamide(12d) was the most effective cell growth [...] Read more.

A series of novel 2-phenylaminopyrimidine (PAP) derivatives structurally related to STI-571 were designed and synthesized. The abilities of these compounds to inhibit proliferation were tested in human chronic myeloid leukemia K562 cells. (E)-3-(2-bromophenyl)-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)phenyl]acrylamide(12d) was the most effective cell growth inhibitor and was 3-fold more potent than STI-571. Full article

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Graphical abstract

118 KiB

Open AccessCommunication

Trametes sp. as a Source of Biopolymer Cross-Linking Agents: Laccase Induced Gelation of Ferulated Arabinoxylans

by Alva Castillo, Agustín Rascón-Chu, Georgina Vargas, Elizabeth Carvajal-Millán, Elisa Valenzuela-Soto, Rogerio R. Sotelo-Mundo and Ana Luisa Martínez

Molecules 2009, 14(10), 4159-4165; https://doi.org/10.3390/molecules14104159 - 16 Oct 2009

Cited by 4 | Viewed by 12524

Abstract

This study examined the feasibility of using Trametes sp. grown under drought conditions to catalyze the covalent cross-linking of ferulated arabinoxylans. The rate of polymerization of ferulated arabinoxylans solutions at 0.5% (w/v) was dose dependent on the laccase concentration in the system. Above [...] Read more.

This study examined the feasibility of using Trametes sp. grown under drought conditions to catalyze the covalent cross-linking of ferulated arabinoxylans. The rate of polymerization of ferulated arabinoxylans solutions at 0.5% (w/v) was dose dependent on the laccase concentration in the system. Above 1.2 nkat laccase/mg ferulated arabinoxylan, the rate of cross-linking reached a plateau, suggesting that the reaction reached saturation. For 2% (w/v) ferulated arabinoxylans treated with laccase (1.6 nkat/mg ferulated arabinoxylan), stable gels were formed after 4 h at 25 °C, with cross-linking contents (diferulic and triferulic acid) contents of 0.03 and 0.015 μg/mg ferulated arabinoxylan, respectively. This study demonstrated that Trametes sp. can be a source of biopolymer cross-linking enzymes like laccase. Full article

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327 KiB

Open AccessArticle

Structural Investigation of Biologically Active Phenolic Compounds Isolated from European Tree Species

by Izabela Redzynia, Natasza E. Ziółkowska, Wiesław R. Majzner, Stefan Willför, Rainer Sjöholm, Patrik Eklund and Grzegorz D. Bujacz

Molecules 2009, 14(10), 4147-4158; https://doi.org/10.3390/molecules14104147 - 16 Oct 2009

Cited by 11 | Viewed by 9843

Abstract

X-ray structures of two compounds isolated from wood knots of coniferous trees, namely dihydrokaempferol (3,5,8,13-tetrahydroxyflavanon) and lariciresinol (3,14-dimetoxy-7,10-epoxylignan-4,15,19-triol), are presented here. Diffraction data for the Dihydrokaempferol crystals were collected on a CAD4 diffractometer and on a synchrotron for the lariciresinol crystal. The investigated [...] Read more.

X-ray structures of two compounds isolated from wood knots of coniferous trees, namely dihydrokaempferol (3,5,8,13-tetrahydroxyflavanon) and lariciresinol (3,14-dimetoxy-7,10-epoxylignan-4,15,19-triol), are presented here. Diffraction data for the Dihydrokaempferol crystals were collected on a CAD4 diffractometer and on a synchrotron for the lariciresinol crystal. The investigated compounds inhibit lipid peroxidation and lariciresinol is additionally a good scavenger of superoxide radicals. The structural data presented in this work provide a useful basis for designing more active compounds with potential use as antioxidants. Full article

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Open AccessArticle

Characterization of Primary Standards for Use in the HPLC Analysis of the Procyanidin Content of Cocoa and Chocolate Containing Products

by William J. Hurst, Bruce Stanley, Jan A. Glinski, Matthew Davey, Mark J. Payne and David A. Stuart

Molecules 2009, 14(10), 4136-4146; https://doi.org/10.3390/molecules14104136 - 15 Oct 2009

Cited by 29 | Viewed by 14867

Abstract

This report describes the characterization of a series of commercially available procyanidin standards ranging from dimers DP = 2 to decamers DP = 10 for the determination of procyanidins from cocoa and chocolate. Using a combination of HPLC with fluorescence detection and MALDI-TOF [...] Read more.

This report describes the characterization of a series of commercially available procyanidin standards ranging from dimers DP = 2 to decamers DP = 10 for the determination of procyanidins from cocoa and chocolate. Using a combination of HPLC with fluorescence detection and MALDI-TOF mass spectrometry, the purity of each standard was determined and these data were used to determine relative response factors. These response factors were compared with other response factors obtained from published methods. Data comparing the procyanidin analysis of a commercially available US dark chocolate calculated using each of the calibration methods indicates divergent results and demonstrate that previous methods may significantly underreport the procyanidins in cocoa-containing products. These results have far reaching implications because the previous calibration methods have been used to develop data for a variety of scientific reports, including food databases and clinical studies. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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147 KiB

Open AccessArticle

New 1-Aryl-3-Substituted Propanol Derivatives as Antimalarial Agents

by Silvia Pérez-Silanes, Luis Berrade, Rory N. García–Sánchez, Adela Mendoza, Silvia Galiano, Berta Martín Pérez-Solórzano, Juan J. Nogal-Ruiz, Antonio R. Martínez-Fernández, Ignacio Aldana and Antonio Monge

Molecules 2009, 14(10), 4120-4135; https://doi.org/10.3390/molecules14104120 - 14 Oct 2009

Cited by 18 | Viewed by 12573

Abstract

This paper describes the synthesis and in vitro antimalarial activity against a P. falciparum 3D7 strain of some new 1-aryl-3-substituted propanol derivatives. Twelve of the tested compounds showed an IC₅₀ lower than 1 μM. These compounds were also tested for cytotoxicity in [...] Read more.

This paper describes the synthesis and in vitro antimalarial activity against a P. falciparum 3D7 strain of some new 1-aryl-3-substituted propanol derivatives. Twelve of the tested compounds showed an IC₅₀ lower than 1 μM. These compounds were also tested for cytotoxicity in murine J774 macrophages. The most active compounds were evaluated for in vivo activity against P. berghei in a 4-day suppressive test. Compound 12 inhibited more than 50% of parasite growth at a dose of 50 mg/kg/day. In addition, an FBIT test was performed to measure the ability to inhibit ferriprotoporphyrin biocrystallization. This data indicates that 1-aryl-3-substituted propanol derivatives hold promise as a new therapeutic option for the treatment of malaria. Full article

(This article belongs to the Special Issue Artemisinin (Qinghaosu): Commemorative Issue in Honor of Professor Youyou Tu on the Occasion of her 80th Anniversary)

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460 KiB

Open AccessReview

Addition and Cycloaddition Reactions of Phosphinyl- and Phosphonyl-2H-Azirines, Nitrosoalkenes and Azoalkenes

by Américo Lemos

Molecules 2009, 14(10), 4098-4119; https://doi.org/10.3390/molecules14104098 - 13 Oct 2009

Cited by 60 | Viewed by 11880

Abstract

An overview of the use of 2H-azirines, conjugated nitrosoalkenes and conjugated azoalkenes bearing phosphorus substituents in addition and cycloaddition reactions is presented, focused on strategies for the synthesis of aminophosphonate and aminophosphine oxide derivatives. Full article

(This article belongs to the Special Issue Alpha- or Beta-aminophosphonates and -phosphinates)

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667 KiB

Open AccessArticle

A New Organofunctional Ethoxysilane Self-Assembly Monolayer for Promoting Adhesion of Rubber to Aluminum

by Fang Wang, Juan Xu, Heyi Luo, Jinggang Wang and Qian Wang

Molecules 2009, 14(10), 4087-4097; https://doi.org/10.3390/molecules14104087 - 12 Oct 2009

Cited by 17 | Viewed by 15082

Abstract

Practical adhesion of rubber to aluminum is measured for various aluminum silanization treatments. In this study, 6-(3-triethoxysilylpropylamino)-1,3,5-triazine-2,4-dithiol (TES) was used as the coupling agent for preparing self-assembly monolayers (SAMs) on an aluminum surface. The structure and chemical composition of the SAMs were analyzed [...] Read more.

Practical adhesion of rubber to aluminum is measured for various aluminum silanization treatments. In this study, 6-(3-triethoxysilylpropylamino)-1,3,5-triazine-2,4-dithiol (TES) was used as the coupling agent for preparing self-assembly monolayers (SAMs) on an aluminum surface. The structure and chemical composition of the SAMs were analyzed using Fourier transform infra-red spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The changes in the surface features of the aluminum surface due to TES treatment were investigated by atomic force microscopy (AFM). The adhesive properties of the silanized aluminum surface and EPDM rubber have been evaluated by a T-peel strength test. The results suggested that the Si-O-Al bonding at aluminum TES interface existed and a TES self-assembly monolayer was formed on the aluminum surface. More than 6.0 KN/m adhesion strength is obtained when the aluminum is silanized with 2.5 mmol/dm³ TES, cured at 160 °C and vulcanized with EPDM rubber at 160 °C for 30 min. It is suggested that the TES self-assembly monolayer is bound to aluminum through its ethoxysilyl functional group, and the thiol function group is strongly crosslinked to EPDM rubber, respectively. Full article

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510 KiB

Open AccessArticle

Application of the Molecular Combing Technique to Starch Granules

by Hua Li, Zhong-Dong Liu, Liu Boxiang, Jian-Hui Chen, You-Ning Sun, Xiao-Ling Lv, Ze-Sheng Zhang, Pin Sun, Pin Zhang and Yang-Li Wang

Molecules 2009, 14(10), 4079-4086; https://doi.org/10.3390/molecules14104079 - 12 Oct 2009

Cited by 2 | Viewed by 11597

Abstract

The molecular combing technique was used to dissociate the nanostructural units of starch granules from the starch fragments after a gelatinization process. With the help of atomic force microscopy (AFM), we observed that some nanostructural chains were just flowing out of the granules. [...] Read more.

The molecular combing technique was used to dissociate the nanostructural units of starch granules from the starch fragments after a gelatinization process. With the help of atomic force microscopy (AFM), we observed that some nanostructural chains were just flowing out of the granules. It proves that there are substantive nanostructural units in the starch granules, a phenomenon not previously observed, so these nanostructural units were defined as suspected intermediates. Furthermore, we conclude that blocklets of starch granules are formed through twisting or distortion of nanochains. Full article

(This article belongs to the Special Issue Microwave Assisted Synthesis)

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357 KiB

Open AccessArticle

Sulphated Zirconia as an Eco-Friendly Catalyst in Acylal Preparation under Solvent-Free Conditions, Acylal Deprotection Assisted by Microwaves, and the Synthesis of Anhydro-Dimers of o-Hydroxybenzaldehydes

by Laura Nadxieli Palacios-Grijalva, Deysi Y. Cruz-González, Leticia Lomas-Romero, Eduardo González-Zamora, Gerardo Ulibarri and Guillermo E. Negrón-Silva

Molecules 2009, 14(10), 4065-4078; https://doi.org/10.3390/molecules14104065 - 12 Oct 2009

Cited by 20 | Viewed by 13068

Abstract

A solvent-free approach is described for the regioselective synthesis of acylals (1,1-diacetates) in shorter reaction times and higher yields, compared to conventional methodology using solvents. In the protection reaction of the o-hydroxybenzaldehyde the formation of acetyl compounds and anhydro-dimers was observed. The [...] Read more.

A solvent-free approach is described for the regioselective synthesis of acylals (1,1-diacetates) in shorter reaction times and higher yields, compared to conventional methodology using solvents. In the protection reaction of the o-hydroxybenzaldehyde the formation of acetyl compounds and anhydro-dimers was observed. The deprotection reaction involves microwave (MW) exposure of diluted reactants in the presence of solid sulphated zirconia (SZ) catalyst that can be easily recovered and reused. The sulphated zirconia was recycled several times without any loss of activity. Full article

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Open AccessArticle

Synthesis of Lipoamino Acids and Their Activity against Cerebral Ischemic Injury

by Li-Yun Yao, Qi Lin, Yin-Yao Niu, Ke-Min Deng, Jian-Hua Zhang and Yang Lu

Molecules 2009, 14(10), 4051-4064; https://doi.org/10.3390/molecules14104051 - 12 Oct 2009

Cited by 30 | Viewed by 10927

Abstract

A series of lipoamino acids were synthesized and their neuroprotective effect against brain ischemia induced by oxygen-glucose deprivation (OGD) on rat cerebral slices was evaluated. Among these compounds, N-stearoyl-L-tyrosine (4), N-stearoyl-L-serine (5) and N-stearoyl-L-threonine (6) exhibited good neuroprotective activity. We [...] Read more.

A series of lipoamino acids were synthesized and their neuroprotective effect against brain ischemia induced by oxygen-glucose deprivation (OGD) on rat cerebral slices was evaluated. Among these compounds, N-stearoyl-L-tyrosine (4), N-stearoyl-L-serine (5) and N-stearoyl-L-threonine (6) exhibited good neuroprotective activity. We found that the neuroprotective activity of lipoamino acids depended on the acyl group, the presence of a free carboxylic function and a free hydroxyl group at the branched chain of the amino acids. The results also showed that 5 was the most active compound, protecting rat brain slices against OGD as well as hydrogen peroxide (H₂O₂) insult at the range of 1–10 M. Full article

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Open AccessReview

Design and Applications of Biodegradable Polyester Tissue Scaffolds Based on Endogenous Monomers Found in Human Metabolism

by Devin G. Barrett and Muhammad N. Yousaf

Molecules 2009, 14(10), 4022-4050; https://doi.org/10.3390/molecules14104022 - 12 Oct 2009

Cited by 87 | Viewed by 17770

Abstract

Synthetic polyesters have deeply impacted various biomedical and engineering fields, such as tissue scaffolding and therapeutic delivery. Currently, many applications involving polyesters are being explored with polymers derived from monomers that are endogenous to the human metabolism. Examples of these monomers include glycerol, [...] Read more.

Synthetic polyesters have deeply impacted various biomedical and engineering fields, such as tissue scaffolding and therapeutic delivery. Currently, many applications involving polyesters are being explored with polymers derived from monomers that are endogenous to the human metabolism. Examples of these monomers include glycerol, xylitol, sorbitol, and lactic, sebacic, citric, succinic, α-ketoglutaric, and fumaric acids. In terms of mechanical versatility, crystallinity, hydrophobicity, and biocompatibility, polyesters synthesized partially or completely from these monomers can display a wide range of properties. The flexibility in these macromolecular properties allows for materials to be tailored according to the needs of a particular application. Along with the presence of natural monomers that allows for a high probability of biocompatibility, there is also an added benefit that this class of polyesters is more environmentally friendly than many other materials used in biomedical engineering. While the selection of monomers may be limited by nature, these polymers have produced or have the potential to produce an enormous number of successes in vitro and in vivo. Full article

(This article belongs to the Special Issue Biodegradation: Organic, Medicinal and Analytical Chemistry)

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Open AccessReview

The Morita-Baylis-Hillman Reaction: Insights into Asymmetry and Reaction Mechanisms by Electrospray Ionization Mass Spectrometry

by Verónica Carrasco-Sanchez, Mario J. Simirgiotis and Leonardo S. Santos

Molecules 2009, 14(10), 3989-4021; https://doi.org/10.3390/molecules14103989 - 12 Oct 2009

Cited by 69 | Viewed by 16302

Abstract

This short review presents new insights on the mechanism and online monitoring using electrospray ionization tandem mass spectrometry (ESI–MS/MS) of Morita–Baylis–Hillman (MBH) reactions. MBH reactions are versatile carbon-carbon organocatalyzed bond forming reactions, making them environmentally friendly due to general organocatalysts employed. The organocatalyst [...] Read more.

This short review presents new insights on the mechanism and online monitoring using electrospray ionization tandem mass spectrometry (ESI–MS/MS) of Morita–Baylis–Hillman (MBH) reactions. MBH reactions are versatile carbon-carbon organocatalyzed bond forming reactions, making them environmentally friendly due to general organocatalysts employed. The organocatalyst behavior, which controls the transition state and thus the enantioselectivities in the obtained products, is very important in the performance of asymmetric MBH transformations. Some recent techniques and advances in asymmetric transformations are reviwed, as well as online reaction monitoring and analysis of the reaction intermediates. The mechanism accepted nowadays is also review through the insights gained from the use of ESI–MS/MS techniques. Full article

(This article belongs to the Special Issue Baylis-Hillman Reaction and Related Processes)

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Open AccessReview

Selenium in Oncology: From Chemistry to Clinics

by Oliver Micke, Lutz Schomburg, Jens Buentzel, Klaus Kisters and Ralph Muecke

Molecules 2009, 14(10), 3975-3988; https://doi.org/10.3390/molecules14103975 - 12 Oct 2009

Cited by 82 | Viewed by 19834

Abstract

The essential trace element selenium, which is a crucial cofactor in the most important endogenous antioxidative systems of the human body, is attracting more and more the attention of both laypersons and expert groups. The interest of oncologists mainly focuses in the following [...] Read more.

The essential trace element selenium, which is a crucial cofactor in the most important endogenous antioxidative systems of the human body, is attracting more and more the attention of both laypersons and expert groups. The interest of oncologists mainly focuses in the following clinical aspects: radioprotection of normal tissues, radiosensitizing in malignant tumors, antiedematous effect, prognostic impact of selenium, and effects in primary and secondary cancer prevention. Selenium is a constituent of the small group of selenocysteine-containing selenoproteins and elicits important structural and enzymatic functions. Selenium deficiency has been linked to increased infection risk and adverse mood states. It has been shown to possess cancer-preventive and cytoprotective activities in both animal models and humans. It is well established that Se has a key role in redox regulation and antioxidant function, and hence in membrane integrity, energy metabolism and protection against DNA damage. Recent clinical trials have shown the importance of selenium in clinical oncology. Our own clinical study involving 48 patients suggest that selenium has a positive effect on radiation-associated secondary lymphedema in patients with limb edemas, as well as in the head and neck region, including endolaryngeal edema. Another randomized phase III study of our group was performed to examine the cytoprotective properties of selenium in radiation oncology. The aim was to evaluate whether sodium selenite is able to compensate a preexisting selenium deficiency and to prevent radiation induced diarrhea in adjuvant radiotherapy for pelvic gynecologic malignancies. Through this study, the significant benefits of sodium selenite supplementation with regards to selenium deficiency and radiotherapy induced diarrhea in patients with cervical and uterine cancer has been shown for the first time in a prospective randomized trial. Survival data imply that supplementation with selenium does not interfere with the positive biological effects of radiation treatment and might constitute a valuable adjuvant therapy option especially in marginally supplied individuals. More recently there were emerging concerns coming up from two large clinical prevention trials (NPC, SELECT), that selenium increases the possible risk of developing diabetes type II. Despite obvious flaws of both studies and good counterarguments, a controversial debate remains on the possible advantage and risks of selenium in cancer prevention. However, in the light of the recent clinical trials the potential benefits of selenium supplementation in tumor patients are undeniable, even if further research is needed. Full article

(This article belongs to the Special Issue Selenium and Tellurium Chemistry)

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Open AccessArticle

Evaluation of Antioxidant and Antibacterial Activities of Aqueous, Methanolic and Alkaloid Extracts from Mitragyna Speciosa (Rubiaceae Family) Leaves

by Suhanya Parthasarathy, Juzaili Bin Azizi, Surash Ramanathan, Sabariah Ismail, Sreenivasan Sasidharan, Mohd I. Mohd. Said and Sharif Mahsufi Mansor

Molecules 2009, 14(10), 3964-3974; https://doi.org/10.3390/molecules14103964 - 9 Oct 2009

Cited by 113 | Viewed by 26252

Abstract

Studies on the antioxidant and antimicrobial activities of Mitragyna speciosa leaf extracts are lacking. In this study the antioxidant properties of water, methanolic and alkaloid M. speciosa leaf extracts were evaluated using the DPPH (2,2-diphenyl-1- picrylhydrazyl) radical scavenging method. The amount of total [...] Read more.

Studies on the antioxidant and antimicrobial activities of Mitragyna speciosa leaf extracts are lacking. In this study the antioxidant properties of water, methanolic and alkaloid M. speciosa leaf extracts were evaluated using the DPPH (2,2-diphenyl-1- picrylhydrazyl) radical scavenging method. The amount of total phenolics and flavanoid contents were also estimated. The DPPH IC₅₀ values of the aqueous, alkaloid and methanolic extracts were 213.4, 104.81 and 37.08 μg/mL, respectively. The total phenolic content of the aqueous, alkaloid and methanolic extracts were 66.0 mg, 88.4, 105.6 mg GAE/g, respectively, while the total flavanoid were 28.2, 20.0 and 91.1 mg CAE/g respectively. The antioxidant activities were correlated with the total phenolic content. This result suggests that the relatively high antioxidant activity of the methanolic extract compared to aqueous and alkaloid extract could be possibly be due to its high phenolic content. The aqueous, alkaloid and methanolic extracts were screened for antimicrobial activity. The extracts showed antimicrobial activity against Salmonella typhi and Bacillus subtilis. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 3.12 to 6.25 mg/mL. The alkaloid extract was found to be most effective against all of the tested organisms. Full article

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Open AccessArticle

An Efficient Method for the N-Bromosuccinimide Catalyzed Synthesis of Indolyl-Nitroalkanes

by Chun-Wei Kuo, Chun-Chao Wang, Hu-Lin Fang, B. Rama Raju, Veerababurao Kavala, Pateliya Mujjamil Habib and Ching-Fa Yao

Molecules 2009, 14(10), 3952-3963; https://doi.org/10.3390/molecules14103952 - 9 Oct 2009

Cited by 23 | Viewed by 12094

Abstract

An efficient and practical method for the synthesis of indolyl-nitroalkane derivatives catalyzed by N-bromosuccinimide is described. The generality of this method was demonstrated by synthesizing an array of diverse 3-substituted indole derivatives by the reaction of different β-nitrostyrenes with various substituted indoles. [...] Read more.

An efficient and practical method for the synthesis of indolyl-nitroalkane derivatives catalyzed by N-bromosuccinimide is described. The generality of this method was demonstrated by synthesizing an array of diverse 3-substituted indole derivatives by the reaction of different β-nitrostyrenes with various substituted indoles. Simple reaction conditions accompanied by good yields of indolyl-nitroalkanes are the merits of this methodology. Full article

(This article belongs to the Special Issue Advances in Heteroaromatic Chemistry)

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Separation, Characterization and Dose-Effect Relationship of the PPARγ-Activating Bio-Active Constituents in the Chinese Herb Formulation ‘San-Ao Decoction’

by Ling Zhou, Yu-Ping Tang, Lu Gao, Xin-Sheng Fan, Chun-Mei Liu and De-Kang Wu

Molecules 2009, 14(10), 3942-3951; https://doi.org/10.3390/molecules14103942 - 9 Oct 2009

Cited by 19 | Viewed by 14438

Abstract

San-ao decoction (SAD), comprising Herba Ephedrae, Radix et Rhizoma Glycyrrhizae and Seneb Armeniacae Amarum, is one of the most popular traditional Chinese medicine (TCM) formulae for asthma. Peroxisome proliferator-activated receptors (PPARs) areey regulators of lipid and glucose metabolism and have become important therapeutic [...] Read more.

San-ao decoction (SAD), comprising Herba Ephedrae, Radix et Rhizoma Glycyrrhizae and Seneb Armeniacae Amarum, is one of the most popular traditional Chinese medicine (TCM) formulae for asthma. Peroxisome proliferator-activated receptors (PPARs) areey regulators of lipid and glucose metabolism and have become important therapeutic targets for various deseases, PPARγ activation might exhibit anti-inflammatory properties in different chronic inflammatory processes. The EtOAc fraction of SAD showed a significant effect on PPARγ activation. A simple and rapid method has been established for separation and characterization of the main compounds in the PPARγ-activating fraction of SAD by ultra-fast HPLC coupled with quadropole time-of-flight mass pectrometry (UPLC-Q-TOF/MS). A total of 10 compounds were identified in the activating fraction of SAD, including amygdalin (1), liquiritin (2), 6′-acetyliquiritin (3), liquiritigenin (4), isoliquiritigenin (5), formononetin (6), licoisoflavanone (7), glycycoumarin (8), glycyrol (9) and uercetin (10). The results also characterized formononetin as a predominant component in this fraction. The dose-effect relationship comparison study of formononetin and the EtOAc fraction of SAD by adding formononetin was performed, the results suggested that formononetin was the major component of the EtOAc fraction of SAD responsible for activating PPARγ, and the method will possibly be applied to study the complex biological active constituents of other TCMs. Full article

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Open AccessReview

Pentacyclic Triterpenoids from the Medicinal Herb, Centella asiatica (L.) Urban

by Jacinda T. James and Ian A. Dubery

Molecules 2009, 14(10), 3922-3941; https://doi.org/10.3390/molecules14103922 - 9 Oct 2009

Cited by 306 | Viewed by 34953

Abstract

Centella asiatica accumulates large quantities of pentacyclic triterpenoid saponins, collectively known as centelloids. These terpenoids include asiaticoside, centelloside, madecassoside, brahmoside, brahminoside, thankuniside, sceffoleoside, centellose, asiatic-, brahmic-, centellic- and madecassic acids. The triterpene saponins are common secondary plant metabolites and are synthesized via the [...] Read more.

Centella asiatica accumulates large quantities of pentacyclic triterpenoid saponins, collectively known as centelloids. These terpenoids include asiaticoside, centelloside, madecassoside, brahmoside, brahminoside, thankuniside, sceffoleoside, centellose, asiatic-, brahmic-, centellic- and madecassic acids. The triterpene saponins are common secondary plant metabolites and are synthesized via the isoprenoid pathway to produce a hydrophobic triterpenoid structure (aglycone) containing a hydrophilic sugar chain (glycone). The biological activity of saponins has been attributed to these characteristics. In planta, the Centella triterpenoids can be regarded as phytoanticipins due to their antimicrobial activities and protective role against attempted pathogen infections. Preparations of C. asiatica are used in traditional and alternative medicine due to the wide spectrum of pharmacological activities associated with these secondary metabolites. Here, the biosynthesis of the centelloid triterpenoids is reviewed; the range of metabolites found in C. asiatica, together with their known biological activities and the chemotype variation in the production of these metabolites due to growth conditions are summarized. These plant-derived pharmacologically active compounds have complex structures, making chemical synthesis an economically uncompetitive option. Production of secondary metabolites by cultured cells provides a particularly important benefit to manipulate and improve the production of desired compounds; thus biotechnological approaches to increase the concentrations of the metabolites are discussed. Full article

(This article belongs to the Special Issue Triterpenes and Triterpenoids 2013)

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Open AccessArticle

Solid-Phase Synthesis of Optically Active Substituted 2 Aminofuranones Using an Activated Carbonate Linker

by Dimitris Matiadis, Kyriakos C. Prousis and Olga Igglessi-Markopoulou

Molecules 2009, 14(10), 3914-3921; https://doi.org/10.3390/molecules14103914 - 30 Sep 2009

Cited by 12 | Viewed by 8770

Abstract

An efficient three-step solid-phase synthesis of diverse 3,5-disubstituted-2-aminofuranones has been developed. α-Hydroxy acids loaded on a nitrophenyl carbonate derivative of Wang resin are used as acylating agents for the C-acylation of active methylene compounds and the resulting intermediates provided, through a cyclative [...] Read more.

An efficient three-step solid-phase synthesis of diverse 3,5-disubstituted-2-aminofuranones has been developed. α-Hydroxy acids loaded on a nitrophenyl carbonate derivative of Wang resin are used as acylating agents for the C-acylation of active methylene compounds and the resulting intermediates provided, through a cyclative cleavage reaction, the desired product. Full article

(This article belongs to the Special Issue Solid Phase Synthesis)

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Inhibitory Effect of Three C-glycosylflavonoids from Cymbopogon citratus (Lemongrass) on Human Low Density Lipoprotein Oxidation

by Roxana Orrego, Elba Leiva and José Cheel

Molecules 2009, 14(10), 3906-3913; https://doi.org/10.3390/molecules14103906 - 30 Sep 2009

Cited by 40 | Viewed by 14764

Abstract

This study assessed the inhibitory effect of three C-glycosylflavonoids from Cymbopogon citratus leaves - isoorientin (1), swertiajaponin (2) and isoorientin 2"-Orhamnoside (3) - on human LDL oxidation. Isolated LDL was incubated with compounds 1-3 and the kinetics of lipid peroxidation were assessed by [...] Read more.

This study assessed the inhibitory effect of three C-glycosylflavonoids from Cymbopogon citratus leaves - isoorientin (1), swertiajaponin (2) and isoorientin 2"-Orhamnoside (3) - on human LDL oxidation. Isolated LDL was incubated with compounds 1-3 and the kinetics of lipid peroxidation were assessed by conjugated diene and malondialdehyde-thiobarbituric acid reactive substances (MDA-TBARS) formation after addition of copper ions. Significant differences (p < 0.05) between the lag time phase of the control and the lag time phase in the presence of the compounds 1 (0.25 µM) and 2 (0.50 µM) were observed. After five hours of incubation all three compounds showed a significant inhibitory effect on MDA-TBARS formation with respect to the control. After six hours of incubation only compound 1 kept a remarkable antioxidant effect. This study demonstrates that isoorientin (1) is an effective inhibitor of in vitro LDL oxidation. As oxidative damage to LDL is a key event in the formation of atherosclerotic lesions, the use of this natural antioxidant may be beneficial to prevent or attenuate atherosclerosis. Full article

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Design of Antimicrobially Active Small Amphiphilic Peptide Dendrimers

by Piotr Polcyn, Margarita Jurczak, Aleksandra Rajnisz, Jolanta Solecka and Zofia Urbanczyk-Lipkowska

Molecules 2009, 14(10), 3881-3905; https://doi.org/10.3390/molecules14103881 - 29 Sep 2009

Cited by 34 | Viewed by 11695

Abstract

Novel polyfunctional small amphiphilic peptide dendrimers characterized by incorporation of a new core compounds – tris-amino acids or tetrakis-amino alcohols that originated from a series of basic amino acids – were efficiently synthesized. These new core elements yielded molecules with multiple [...] Read more.

Novel polyfunctional small amphiphilic peptide dendrimers characterized by incorporation of a new core compounds – tris-amino acids or tetrakis-amino alcohols that originated from a series of basic amino acids – were efficiently synthesized. These new core elements yielded molecules with multiple branching and (+5)/(+6) charge at the 1-st dendrimer generation. Dendrimers exhibited significant antimicrobial potency against Gram(+) and Gram(-) strains involving also multiresistant reference strains (S. aureus ATCC 43300 and E. coli ATCC BAA-198). In addition, high activity against fungi from the Candida genus was detected. More charged and more hydrophobic peptide dendrimers expressed hemolytic properties. Full article

(This article belongs to the Special Issue Dendrimers - from Synthesis to Applications)

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A New Look at the Most Successful Prodrugs for Active Vitamin D (D Hormone): Alfacalcidol and Doxercalciferol

by Noboru Kubodera

Molecules 2009, 14(10), 3869-3880; https://doi.org/10.3390/molecules14103869 - 29 Sep 2009

Cited by 38 | Viewed by 16879

Abstract

Alfacalcidol (1α-hydroxyvitamin D₃) has been widely used since 1981 as a prodrug for calcitriol (1α,25-dihydroxyvitamin D₃) in the treatment of hypocalcemia, chronic renal failure, hypoparathyroidism and osteoporosis. More recently, doxercalciferol (1α-hydroxyvitamin D₂) has been used since 1999 [...] Read more.

Alfacalcidol (1α-hydroxyvitamin D₃) has been widely used since 1981 as a prodrug for calcitriol (1α,25-dihydroxyvitamin D₃) in the treatment of hypocalcemia, chronic renal failure, hypoparathyroidism and osteoporosis. More recently, doxercalciferol (1α-hydroxyvitamin D₂) has been used since 1999 as a prodrug for 1α,25-dihydroxyvitamin D₂ for the treatment of secondary hyperparathyroidism. Currently, six forms of vitamin D are known. They range from vitamin D₂ to vitamin D₇and are distinguished by their differing side chains. Only vitamin D₂ and vitamin D₃ have been found to be biologically active based on the elucidation of activation pathways. Alfacalcidol and osteoporosis/doxercalciferol and secondary hyperparathyroidism are discussed, with a new look at old compounds including their practical syntheses. Full article

(This article belongs to the Special Issue Prodrugs)

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Molecules, Volume 14, Issue 10 (October 2009) – 33 articles , Pages 3844-4299

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