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Molecules, Volume 14, Issue 6 (June 2009) – 31 articles , Pages 1966-2305

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605 KiB  
Review
Ionic Liquids in Tribology
by Ichiro Minami
Molecules 2009, 14(6), 2286-2305; https://doi.org/10.3390/molecules14062286 - 24 Jun 2009
Cited by 624 | Viewed by 24952
Abstract
Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research [...] Read more.
Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided. Full article
(This article belongs to the Collection Ionic Liquids)
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979 KiB  
Article
Synthesis of Symmetrical and Non-symmetrical Diimines from Dimedone
by Bahjat A. Saeed and Ibrahim A. Musad
Molecules 2009, 14(6), 2278-2285; https://doi.org/10.3390/molecules14062278 - 24 Jun 2009
Cited by 4 | Viewed by 10253
Abstract
Symmetrical and non-symmetrical diimines derived from dimedone were synthesized by the reaction of their corresponding enaminothiones with primary amines. The synthesized compounds were characterized using micro analytical data and NMR spectroscopy. Theoretical calculations by B3LYP/6-31G(d,p) level of theory show that the enolic form [...] Read more.
Symmetrical and non-symmetrical diimines derived from dimedone were synthesized by the reaction of their corresponding enaminothiones with primary amines. The synthesized compounds were characterized using micro analytical data and NMR spectroscopy. Theoretical calculations by B3LYP/6-31G(d,p) level of theory show that the enolic form is the most stable within the possible tautomeric forms of the compounds. Full article
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149 KiB  
Article
A New Cadinane Sesquiterpene from the Marine Brown Alga Dictyopteris divaricata
by Wei Wen, Fang Li, Nai-Yun Ji, Xiao-Ming Li, Chuan-Ming Cui, Xiao-Dong Li, Li-Na Zhang, Qin-Zhao Xue and Bin-Gui Wang
Molecules 2009, 14(6), 2273-2277; https://doi.org/10.3390/molecules14062273 - 24 Jun 2009
Cited by 14 | Viewed by 10668
Abstract
A sample of the marine brown alga D. divaricata collected off the coast of Yantai (P.R. China) was dried, powdered, and extracted with the mixture of CHCl3 and MeOH (1:1, v/v). By a combination of silica gel and Sephadex LH-20 column chromatography [...] Read more.
A sample of the marine brown alga D. divaricata collected off the coast of Yantai (P.R. China) was dried, powdered, and extracted with the mixture of CHCl3 and MeOH (1:1, v/v). By a combination of silica gel and Sephadex LH-20 column chromatography and preparative TLC, a new cadinane sesquiterpene 1,4-epoxymuurolan-5β-ol (1) was isolated from this species. Its structure was established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data. Full article
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149 KiB  
Article
Heterocyclic-2-carboxylic Acid (3-Cyano-1,4-di-N-oxidequinoxalin-2-yl)amide Derivatives as Hits for the Development of Neglected Disease Drugs
by Saioa Ancizu, Elsa Moreno, Enrique Torres, Asunción Burguete, Silvia Pérez-Silanes, Diego Benítez, Raquel Villar, Beatriz Solano, Adoración Marín, Ignacio Aldana, Hugo Cerecetto, Mercedes González and Antonio Monge
Molecules 2009, 14(6), 2256-2272; https://doi.org/10.3390/molecules14062256 - 22 Jun 2009
Cited by 52 | Viewed by 15126
Abstract
Neglected diseases represent a major health problem. It is estimated that one third of the world population is infected with tuberculosis (TB). Besides TB, Chagas disease, affects approximately 20 million people. Quinoxalines display great activities against TB and Chagas. Forty new quinoxaline 1,4-di- [...] Read more.
Neglected diseases represent a major health problem. It is estimated that one third of the world population is infected with tuberculosis (TB). Besides TB, Chagas disease, affects approximately 20 million people. Quinoxalines display great activities against TB and Chagas. Forty new quinoxaline 1,4-di-N-oxide derivatives have been prepared and tested against M. tuberculosis and T. cruzi. Carboxylic acid quinoxaline 1,4-di-N-oxides (CAQDOs) 5 and 17 showed MIC values on the same order as the reference antituberculosis drug, rifampicin. Meanwhile, CAQDOs 12 and 22 presented IC50 values in the same order as the anti-chagasic drug, nifurtimox. Full article
(This article belongs to the Special Issue Neglected Diseases: Medicinal Chemistry and Natural Product Chemistry)
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23 KiB  
Editorial
Full Open Access Journals Have Increased Impact Factors
by Shu-Kun Lin
Molecules 2009, 14(6), 2254-2255; https://doi.org/10.3390/molecules14062254 - 22 Jun 2009
Cited by 10 | Viewed by 38602
Abstract
We are pleased to report the increase of the impact factors of MDPI journals during 2007 and 2008. In 2005 and part of 2006, the use of a two tier publication system, whereby we offered full Open Access publication to those authors willing [...] Read more.
We are pleased to report the increase of the impact factors of MDPI journals during 2007 and 2008. In 2005 and part of 2006, the use of a two tier publication system, whereby we offered full Open Access publication to those authors willing to contribute financially to support this option, while providing the alternative choice of free publication without Open Access for those authors who preferred not to pay, resulted in the obviously decreased impact factors seen in 2006 [...] Full article
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212 KiB  
Article
Two New Steroidal Saponins from Allium macrostemon Bunge and Their Cytotoxity on Different Cancer Cell Lines
by Hai-Feng Chen, Guang-Hui Wang, Qiang Luo, Nai-Li Wang and Xin-Sheng Yao
Molecules 2009, 14(6), 2246-2253; https://doi.org/10.3390/molecules14062246 - 19 Jun 2009
Cited by 41 | Viewed by 10798
Abstract
Two new steroidal saponins (1 and 2) were isolated from the dried bulbs of Allium macrostemon Bunge. Their structures were elucidated by the spectral data as 26-O-β-D-glucopyranosyl-5α-furost-25 (27)-ene-3β, 12β, 22, 26-tetraol-3-O- [...] Read more.
Two new steroidal saponins (1 and 2) were isolated from the dried bulbs of Allium macrostemon Bunge. Their structures were elucidated by the spectral data as 26-O-β-D-glucopyranosyl-5α-furost-25 (27)-ene-3β, 12β, 22, 26-tetraol-3-O-β-D-glucopyranosyl (1→2) [β-D-glucopyranosyl (1→3)]-β-D-glucopyranosyl (1→4)-β-D-galactopyranoside (1) and 26-O-β-D-glucopyranosyl-5β-furost-20 (22)-25 (27)-dien-3β, 12β, 26-triol-3-O-β-D-glucopyranosyl (1→2)-β-D-galactopyranoside (2), respectively. Their cytotoxic activities on several cancer cell lines (MCF-7, NCI-H460, SF-268 and HepG2) were tested. 1 showed special cytotoxity on SF-268, while 2 showed cytotoxity on NCI-H460 and SF-268 cell lines, respectively. Full article
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206 KiB  
Article
A Facile Route to C2-Substituted Imidazolium Ionic Liquids
by Elliot Ennis and Scott T. Handy
Molecules 2009, 14(6), 2235-2245; https://doi.org/10.3390/molecules14062235 - 19 Jun 2009
Cited by 22 | Viewed by 12562
Abstract
A convenient route for the preparation of C2-substituted imidazolium ionic liquids is reported. This method involves the alkylation of N-heterocyclic carbenes, which are readily generated from the C2-unsubstituted imidazolium ionic liquids. It works well for non-functionalized alkyl chlorides, and less well for [...] Read more.
A convenient route for the preparation of C2-substituted imidazolium ionic liquids is reported. This method involves the alkylation of N-heterocyclic carbenes, which are readily generated from the C2-unsubstituted imidazolium ionic liquids. It works well for non-functionalized alkyl chlorides, and less well for alkyl bromides and iodides, likely due to competing elimination reactions. The resulting C2-substituted salts can be transformed into ionic liquids via standard anion metathesis reactions. Full article
(This article belongs to the Collection Ionic Liquids)
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252 KiB  
Article
Synthesis and Characterization of Photo-Responsive Carbosilane Dendrimers
by Tetsuo Koyama, Ken Hatano, Koji Matsuoka, Yasuaki Esumi and Daiyo Terunuma
Molecules 2009, 14(6), 2226-2234; https://doi.org/10.3390/molecules14062226 - 18 Jun 2009
Cited by 8 | Viewed by 7417
Abstract
Preparation of photo-responsive carbosilane dendrimers bearing 4-phenylazo-benzonitrile units on their molecular surface has been accomplished, and their both photo and thermal behaviors have also been characterized. These functional dendrimers suggest that the apparent molecular sizes of the cis-isomers are smaller than those [...] Read more.
Preparation of photo-responsive carbosilane dendrimers bearing 4-phenylazo-benzonitrile units on their molecular surface has been accomplished, and their both photo and thermal behaviors have also been characterized. These functional dendrimers suggest that the apparent molecular sizes of the cis-isomers are smaller than those of the corresponding trans-isomers, since the molecular diameter of these dendrimers would be shorter on the basis of trans→cis photo-isomerization of azobenzene. Full article
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252 KiB  
Article
Examination of Imprinting Process with Molsidomine as a Template
by Piotr Luliński and Dorota Maciejewska
Molecules 2009, 14(6), 2212-2225; https://doi.org/10.3390/molecules14062212 - 17 Jun 2009
Cited by 13 | Viewed by 8802
Abstract
Eight different functional monomers were used with ethylene glycol dimethacrylate as a cross-linker and molsidomine as a template to obtain molecularly imprinted polymers (MIPs). Non-covalent interactions between molsidomine and each functional monomer in DMSO prior to thermal bulk polymerization were utilized. On the [...] Read more.
Eight different functional monomers were used with ethylene glycol dimethacrylate as a cross-linker and molsidomine as a template to obtain molecularly imprinted polymers (MIPs). Non-covalent interactions between molsidomine and each functional monomer in DMSO prior to thermal bulk polymerization were utilized. On the basis of calculated imprinting factors, MIP prepared with N,N’-diallyltartaramide was chosen for further investigations. Examination of interactions in the prepolymerization complex between molsidomine and N,N’-diallyltartaramide was performed using the Job method. The absorbance of isomolar solutions reaching a maximum for the molar ratio of template to monomer equal to 1:4. Scatchard analysis was used for estimation of the dissociation constants and the maximum amounts of binding sites. The polymer based on N,N’-diallyltartaramide has two classes of heterogeneous binding sites characterized by two values of Kd and two Bmax: Kd(1) = 1.17 mM-1 and Bmax(1) = 0.8 μmol/mg for the higher affinity binding sites, and Kd(2) = 200 μM-1 and Bmax(2) = 2.05 μmol/mg for the lower affinity binding sites. Furthermore, effects of pH and organic solvent on binding properties of MIP and NIP were investigated, together with release of molsidomine from both MIP and NIP. Full article
(This article belongs to the Special Issue ECSOC-12)
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288 KiB  
Editorial
Phenolics: From Chemistry to Biology
by David M. Pereira, Patrícia Valentão, José A. Pereira and Paula B. Andrade
Molecules 2009, 14(6), 2202-2211; https://doi.org/10.3390/molecules14062202 - 17 Jun 2009
Cited by 528 | Viewed by 29195
Abstract
In recent years, few classes of natural products have received as much attention as phenolics and polyphenols. This special issue of Molecules, “Phenolics and Polyphenolics”, is a remarkable confirmation of this trend. Several aspects related to phenolics chemistry, comprising the several classes, [...] Read more.
In recent years, few classes of natural products have received as much attention as phenolics and polyphenols. This special issue of Molecules, “Phenolics and Polyphenolics”, is a remarkable confirmation of this trend. Several aspects related to phenolics chemistry, comprising the several classes, will be discussed. In addition, the increasing interest in phenolics’ biological activities is covered, and several works addressing this matter are referred. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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235 KiB  
Communication
Determination of the Volatile Composition of Rhodobryum giganteum (Schwaegr.) Par. (Bryaceae) Using Solid-phase Microextraction and Gas Chromatography/Mass Spectrometry (GC/MS)
by Lin Li and Jiancheng Zhao
Molecules 2009, 14(6), 2195-2201; https://doi.org/10.3390/molecules14062195 - 17 Jun 2009
Cited by 24 | Viewed by 10558
Abstract
A total of 38 volatile components were identified in Rhodobryum giganteum (Schwaegr.) Par. collected from two different geographic regions by headspace solid-phase microextraction (HS-SPME), combined with gas chromatography/mass spectrometry (GC/MS). The volatile components included some aliphatic and aromatic aldehydes, monoterpene hydrocarbons and a [...] Read more.
A total of 38 volatile components were identified in Rhodobryum giganteum (Schwaegr.) Par. collected from two different geographic regions by headspace solid-phase microextraction (HS-SPME), combined with gas chromatography/mass spectrometry (GC/MS). The volatile components included some aliphatic and aromatic aldehydes, monoterpene hydrocarbons and a sesquiterpene (α-farnesene), with 1-methoxy-2-propyl acetate and n-hexanal being found to be the most abundant volatile components. Analysis of the chemical constituents in the volatile oil of the two samples showed that ten compounds were shared. Full article
494 KiB  
Article
Synthesis of Two New Hemisynthetic Diterpenylhydroquinones from Natural Ent-Labdanes
by Luis Espinoza Catalán, Karen Catalán Marín, Alejandro Madrid Villegas, Héctor Carrasco Altamirano, Joan Villena García and Mauricio Cuellar Fritis
Molecules 2009, 14(6), 2181-2194; https://doi.org/10.3390/molecules14062181 - 17 Jun 2009
Cited by 5 | Viewed by 10150
Abstract
The synthesis and structural determination of two new diterpenylhydroquinones: 2β-acetoxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-diene(1) and 2β-hydroxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-dieneis reported (2). These compounds were obtained by coupling via Electrophilic Aromatic Substitution (EAS) of 1,4-hydroquinone with primary or tertiary allyl alcohol [...] Read more.
The synthesis and structural determination of two new diterpenylhydroquinones: 2β-acetoxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-diene(1) and 2β-hydroxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-dieneis reported (2). These compounds were obtained by coupling via Electrophilic Aromatic Substitution (EAS) of 1,4-hydroquinone with primary or tertiary allyl alcohol derivatives of the natural ent-labdanes 3 and 4. With this new method, the best results were observed when mixtures of the primary alcohol derivatives 5-6 (26% yield of compound 1) and diol derivatives 9-10 (28% yield of compound 2) were used. Full article
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157 KiB  
Article
Effect of Extraction Solvent/Technique on the Antioxidant Activity of Selected Medicinal Plant Extracts
by Bushra Sultana, Farooq Anwar and Muhammad Ashraf
Molecules 2009, 14(6), 2167-2180; https://doi.org/10.3390/molecules14062167 - 15 Jun 2009
Cited by 861 | Viewed by 51024
Abstract
Theeffects of four extracting solvents [absolute ethanol, absolute methanol, aqueous ethanol (ethanol: water, 80:20 v/v) and aqueous methanol (methanol: water, 80:20 v/v)] and two extraction techniques (shaking and reflux) on the antioxidant activity of extracts of barks of Azadirachta indica, Acacia nilotica, [...] Read more.
Theeffects of four extracting solvents [absolute ethanol, absolute methanol, aqueous ethanol (ethanol: water, 80:20 v/v) and aqueous methanol (methanol: water, 80:20 v/v)] and two extraction techniques (shaking and reflux) on the antioxidant activity of extracts of barks of Azadirachta indica, Acacia nilotica, Eugenia jambolana, Terminalia arjuna, leaves and roots of Moringa oleifera, fruit of Ficus religiosa,and leaves of Aloe barbadensis were investigated. The tested plant materials contained appreciable amounts of total phenolic contents (0.31-16.5 g GAE /100g DW), total flavonoid (2.63-8.66 g CE/100g DW); reducing power at 10 mg/mL extract concentration (1.36-2.91), DPPH. scavenging capacity (37.2-86.6%), and percent inhibition of linoleic acid (66.0-90.6%). Generally higher extract yields, phenolic contents and plant material antioxidant activity were obtained using aqueous organic solvents, as compared to the respective absolute organic solvents. Although higher extract yields were obtained by the refluxing extraction technique, in general higher amounts of total phenolic contents and better antioxidant activity were found in the extracts prepared using a shaker. Full article
224 KiB  
Article
Extraction with SPME and Synthesis of 2-Methyl-6-vinylpyrazine by a ‘One Pot’ Reaction Using Microwaves
by Norma Robledo, Jaime Escalante and René Arzuffi
Molecules 2009, 14(6), 2160-2166; https://doi.org/10.3390/molecules14062160 - 15 Jun 2009
Cited by 3 | Viewed by 10776
Abstract
A synthesis of 2-methyl-6-vinylpyrazine was carried out by way of a ‘one pot’ reaction. In order to establish the efficiency of this synthesis the extraction of the volatiles released by male papaya fruit flies was performed by SPME (solid phase micro-extraction). The compound [...] Read more.
A synthesis of 2-methyl-6-vinylpyrazine was carried out by way of a ‘one pot’ reaction. In order to establish the efficiency of this synthesis the extraction of the volatiles released by male papaya fruit flies was performed by SPME (solid phase micro-extraction). The compound was separated and identified using GC/MSD (gas chromatography/mass spectrometry detector). Full article
(This article belongs to the Special Issue Microwave Assisted Synthesis)
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166 KiB  
Article
Cyclization of Hydrazones of 2-Acetyl-1-naphthol and 1-Acetyl-2-naphthol with Triphosgene. Synthesis of Spiro Naphthoxazine Dimers
by Abdullah Saad Al-Bogami, Abdullah Mohammed Al-Majid, Mohammed Ali Al-Saad, Ahmed Amine Mousa, Sara Abdullah Al-Mazroa and Hamad Zaid Alkhathlan
Molecules 2009, 14(6), 2147-2159; https://doi.org/10.3390/molecules14062147 - 12 Jun 2009
Cited by 17 | Viewed by 13588
Abstract
Cyclization of hydrazones derived from 2-acetyl-1-naphthol and 1-acetyl-2-naphthol with triphosgene gave naphtho[1,2-e]-1,3-oxazines, naphtho[2,1-e]-1,3-oxazines or their spiro dimers depending on the molar ratio of triphosgene used for the cyclization. Full article
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447 KiB  
Article
2β-(Isobutyryloxy)florilenalin, a Sesquiterpene Lactone Isolated from the Medicinal Plant Centipeda minima, Induces Apoptosis in Human Nasopharyngeal Carcinoma CNE Cells
by Miaoxian Su, Yaolan Li, Hau Yin Chung and Wencai Ye
Molecules 2009, 14(6), 2135-2146; https://doi.org/10.3390/molecules14062135 - 12 Jun 2009
Cited by 38 | Viewed by 13840
Abstract
Centipeda minima is a medicinal plant reputed in China as a remedy for nasopharyngeal carcinoma (NPC). In this study, bioactivity-guided fractionation of the anti-NPC compound(s) from C. minima led to the isolation of 2β-(isobutyryloxy)florilenalin (IF), a sesquiterpene lactone. IF showed significant dose- and [...] Read more.
Centipeda minima is a medicinal plant reputed in China as a remedy for nasopharyngeal carcinoma (NPC). In this study, bioactivity-guided fractionation of the anti-NPC compound(s) from C. minima led to the isolation of 2β-(isobutyryloxy)florilenalin (IF), a sesquiterpene lactone. IF showed significant dose- and time- dependent inhibition on the growth of the human nasopharyngeal carcinoma epithelia cells (CNE). It induced apoptosis in CNE cells, as shown by the accumulation of sub-G1 cell population, DNA fragmentation and nuclear condensation, caspase-3 activation and PARP cleavage. Such induction was associated with the depletion of mitochondrial membrane potential (ΔΨm) and the release of cytochrome c to cytosol to regulate the expression of Bcl-2 family proteins. These activities led to the cleavage of caspases and the trigger of cell death process. Overall, IF in C. minima showed potent antiproliferative effect of C. minima on NPC cells, suggesting that the plant deserves more extensive investigation for its potential medicinal application. Full article
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Article
Effect of Ionic Liquids as the Mobile Phase Additives on the HPLC Resolution of Four Active Compounds from Sophora flavescens Ait
by Minglei Tian, Junyu Liu and Kyung Ho Row
Molecules 2009, 14(6), 2127-2134; https://doi.org/10.3390/molecules14062127 - 11 Jun 2009
Cited by 17 | Viewed by 10304
Abstract
The retention behaviour of four active compounds from Sophora Flavescens Ait using three ionic liquids as mobile phase modifiers was examined. The effect of the pH and the amount of ionic liquid modifier on the retention of these compounds was determined in methanol/water [...] Read more.
The retention behaviour of four active compounds from Sophora Flavescens Ait using three ionic liquids as mobile phase modifiers was examined. The effect of the pH and the amount of ionic liquid modifier on the retention of these compounds was determined in methanol/water (v/v) as the mobile phase containing different ionic liquids ranging in concentration from 0.1 mmol/L to 3.0 mmol/L. The ionic liquids showed promise as additives in high-performance liquid chromatography. Full article
(This article belongs to the Collection Ionic Liquids)
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281 KiB  
Article
Highly Efficient Esterification of Ferulic Acid Under Microwave Irradiation
by Nian-Guang Li, Zhi-Hao Shi, Yu-Ping Tang, Bao-Quan Li and Jin-Ao Duan
Molecules 2009, 14(6), 2118-2126; https://doi.org/10.3390/molecules14062118 - 10 Jun 2009
Cited by 39 | Viewed by 12243
Abstract
A highly efficient synthesis of alkyl ferulates under microwave irradiation is described. The time of these reactions ranged from 3 to 5 minutes, which was much shorter than the traditional synthetic methods, and the alkyl ferulates were obtained in higher yields. Full article
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Article
Synthesis of a Diamino Substituted Terphenyldivinyl Chromophore
by Zhen-Ting Du, Ru Liu, Jun-Ru Wang and An-Pai Li
Molecules 2009, 14(6), 2111-2117; https://doi.org/10.3390/molecules14062111 - 10 Jun 2009
Cited by 3 | Viewed by 12012
Abstract
(E,E)-1,4-bis(4'-aminostyryl)-2,5-bis(octyloxy)-benzene (6) and its derivative (E,E)-1,4-bis(4'-acetamidostyryl)-2,5-bis(octyloxy)-benzene (7) were synthesized and characterized after alkylation, bromomethylation, Horner-Emmons reaction and reduction from hydroquinone. In order to gain more molecular electronic data, HOMO and LUMO of compound 6 have been calculated by Gaussian 03 W. Full article
(This article belongs to the Special Issue Macromolecules: Chemistry, Medicinal and Functional Materials)
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1889 KiB  
Review
Sonochemical Preparation of Polymer Nanocomposites
by Ke Zhang, Bong-Jun Park, Fei-Fei Fang and Hyoung Jin Choi
Molecules 2009, 14(6), 2095-2110; https://doi.org/10.3390/molecules140602095 - 10 Jun 2009
Cited by 78 | Viewed by 16293
Abstract
Thisreview covers sonochemical fabrication of polymer nanocomposites. In addition to its application to the synthesis of various polymeric systems, due to its powerful efficiency, sonochemistry has been widely used not only as the assistant of dispersion for nanomaterials such as carbon nanotubes (CNT) [...] Read more.
Thisreview covers sonochemical fabrication of polymer nanocomposites. In addition to its application to the synthesis of various polymeric systems, due to its powerful efficiency, sonochemistry has been widely used not only as the assistant of dispersion for nanomaterials such as carbon nanotubes (CNT) and organophillic clay, but also as a special initiator to enhance polymerization for fabrication of polymer nanocomposites with CNT and metallic nanoparticles. Recent developments in the preparation of multi-walled carbon nanotube/polymer nanocomposites with polystyrene and PMMA, magnetic particle/CNT composites and polymer/clay nanocomposites along with their physical characteristics and potential engineering applications will be introduced. Physical characterizations include morphological, thermal, and rheological properties under either an applied electric or magnetic field. Full article
(This article belongs to the Special Issue Sonochemistry-organic synthesis)
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168 KiB  
Article
Dammarane-type Triterpene Saponins from the Flowers of Panax notoginseng
by Jing-Rong Wang, Yuko Yamasaki, Takashi Tanaka, Isao Kouno and Zhi-Hong Jiang
Molecules 2009, 14(6), 2087-2094; https://doi.org/10.3390/molecules14062087 - 10 Jun 2009
Cited by 43 | Viewed by 11655
Abstract
Four new dammarane-type triterpene saponins named floranotoginsenosides A (1), B (2), C (3) and D (4), together with five known triterpene saponins, were isolated from the flowers of Panax notoginseng. Their structures were elucidated on the basis of spectral and chemical evidence. Full article
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437 KiB  
Article
Chemical Composition of the Essential Oils of the Flowers, Leaves and Stems of Two Senecio polyanthemoides Sch. Bip. Samples from South Africa
by Lawal A. Oladipupo and Oyedeji O. Adebola
Molecules 2009, 14(6), 2077-2086; https://doi.org/10.3390/molecules14062077 - 9 Jun 2009
Cited by 28 | Viewed by 10205
Abstract
The essential oils of the flowers, leaves and stems of Senecio polyanthemoides Sch. Bip. Samples collected from two different localities within the city of uMhlathuze, KwaZulu-Natal Province (South Africa) were isolated by hydrodistillation and analyzed using GC and GC/MS. Twenty-six constituents were identified, [...] Read more.
The essential oils of the flowers, leaves and stems of Senecio polyanthemoides Sch. Bip. Samples collected from two different localities within the city of uMhlathuze, KwaZulu-Natal Province (South Africa) were isolated by hydrodistillation and analyzed using GC and GC/MS. Twenty-six constituents were identified, representing an average of 86.0 - 99.6% of the total oil composition. The chemical profile reveals the dominance of monoterpenoid compounds, although some quantitative variance was noticed. The main constituents of the oils were limonene (3.1 – 43.0%), p-cymene (4.9-36.3%), β-selinene (1.3-32.7%), α-pinene (1.8-21.4%), β-pinene (7.6-16.5%) and 1,8-cineole (9.3-11.4%), caryophyllene oxide (4.1-13.4%) and humulene epoxide II (8.6-10.3%). Full article
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Article
Quantitative Structure ‒ Antiprotozoal Activity Relationships of Sesquiterpene Lactones
by Thomas J. Schmidt, Amal M. M. Nour, Sami A. Khalid, Marcel Kaiser and Reto Brun
Molecules 2009, 14(6), 2062-2076; https://doi.org/10.3390/molecules14062062 - 8 Jun 2009
Cited by 109 | Viewed by 19369
Abstract
Prompted by results of our previous studies where we found high activity of some sesquiterpene lactones (STLs) against Trypanosoma brucei rhodesiense (which causes East African sleeping sickness), we have now conducted a structure-(in-vitro)-activity study on a set of 40 STLs against [...] Read more.
Prompted by results of our previous studies where we found high activity of some sesquiterpene lactones (STLs) against Trypanosoma brucei rhodesiense (which causes East African sleeping sickness), we have now conducted a structure-(in-vitro)-activity study on a set of 40 STLs against T. brucei rhodesiense, T. cruzi, Leishmania donovani and Plasmodium falciparum. Furthermore, cytotoxic activity against L6 rat skeletal myoblast cells was assessed. Some of the compounds possess high activity, especially against T. brucei (e.g. helenalin and some of its esters with IC50-values of 0.05-0.1 µM, which is about 10 times lower than their cytotoxic activity). It was found that all investigated antiprotozoal activities are significantly correlated with cytotoxicity and the major determinants for activity are a,b-unsaturated structural elements, also known to be essential for other biological activities of STLs. It was observed, however, that certain compounds are considerably more toxic against protozoa than against mammalian cells while others are more cytotoxic than active against the protozoa. A comparative QSAR analysis was therefore undertaken, in order to discern the antiparasitic activity of STLs against T. brucei and cytotoxicity. Both activities were found to depend to a large extent on the same structural elements and molecular properties. The observed variance in the biological data can be explained in terms of subtle variations in the relative influences of various molecular descriptors. Full article
(This article belongs to the Special Issue Neglected Diseases: Medicinal Chemistry and Natural Product Chemistry)
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358 KiB  
Article
Inhibitory Effects of Morinda officinalis Extract on Bone Loss in Ovariectomized Rats
by Nan Li, Lu-Ping Qin, Ting Han, Yan-Bin Wu, Qiao-Yan Zhang and Hong Zhang
Molecules 2009, 14(6), 2049-2061; https://doi.org/10.3390/molecules14062049 - 8 Jun 2009
Cited by 46 | Viewed by 16344
Abstract
The present study was undertaken to investigate the protective effects of ethanol extract from the root of Morinda Officinalis (RMO) on ovariectomy-induced bone loss. Administration of RMO extract increased trabecular bone mineral content and bone mineral density of tibia, improved the levels of [...] Read more.
The present study was undertaken to investigate the protective effects of ethanol extract from the root of Morinda Officinalis (RMO) on ovariectomy-induced bone loss. Administration of RMO extract increased trabecular bone mineral content and bone mineral density of tibia, improved the levels of phosphorus (P), calcium (Ca) and OPG, decreased the levels of DPD/Cr, TRAP, ACTH and corticosterone, but did not reverse the levels of ALP, TNF-α and IL-6 in serum of ovariectomized rats. These findings demonstrated that RMO extract reduced bone loss in ovariectomized rats, probably via the inhibition of bone resorption, but was not involved with bone formation. Anthraquinones and polysaccharides from Morinda officinals could be responsible for their antiosteoporotic activity, and the action mechanism of these constituents needs to be further studied. Therefore, RMO has the potential to develop a clinically useful antiosteoporotic agent. Full article
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282 KiB  
Communication
Biotransformation of Ginsenoside Rf to Rh1 by Recombinant β-Glucosidase
by Chang-Chun Ruan, Hao Zhang, Lian-Xue Zhang, Zhi Liu, Guang-Zhi Sun, Jun Lei, Yu-Xia Qin, Yi-Nan Zheng, Xiang Li and Hong-Yu Pan
Molecules 2009, 14(6), 2043-2048; https://doi.org/10.3390/molecules14062043 - 8 Jun 2009
Cited by 39 | Viewed by 13872
Abstract
An Aspergillus niger strain was isolated from the soil around ginseng fruit. In vitro enzyme assays showed that this strain had the ability to transform total ginsenosides (TGS) into several new products. In a further biochemical study, a β-glucosidase gene isolated from this [...] Read more.
An Aspergillus niger strain was isolated from the soil around ginseng fruit. In vitro enzyme assays showed that this strain had the ability to transform total ginsenosides (TGS) into several new products. In a further biochemical study, a β-glucosidase gene isolated from this strain, bgl1, was expressed in Saccharomyces cerevisiae. His-tagged BGL1 protein (~170 kD) showed the ability to transform ginsenoside Rf into Rh1. Full article
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202 KiB  
Article
The Synthesis of Some Perhydrobenzimidazolinium Salts and Their Application in Pd-Carbene Catalyzed Heck and Suzuki Reactions
by Murat Yiğit
Molecules 2009, 14(6), 2032-2042; https://doi.org/10.3390/molecules14062032 - 5 Jun 2009
Cited by 15 | Viewed by 8162
Abstract
Novel 1,3-dialkylperhydrobenzimidazolinium chloride salts were prepared as precursors of N-heterocyclic carbenes 3a-e by reacting N,N’-dialkylcyclohexandiamine, triethyl orthoformate and ammonium chloride. The salts were characterized spectroscopically and the complexes formed in situ from Pd(OAc)2 and 3 have been tested as catalysts [...] Read more.
Novel 1,3-dialkylperhydrobenzimidazolinium chloride salts were prepared as precursors of N-heterocyclic carbenes 3a-e by reacting N,N’-dialkylcyclohexandiamine, triethyl orthoformate and ammonium chloride. The salts were characterized spectroscopically and the complexes formed in situ from Pd(OAc)2 and 3 have been tested as catalysts in homogenous Heck and Suzuki reactions. Full article
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414 KiB  
Article
Pentacyclic Triterpene Distribution in Various Plants – Rich Sources for a New Group of Multi-Potent Plant Extracts
by Sebastian Jäger, Holger Trojan, Thomas Kopp, Melanie N. Laszczyk and Armin Scheffler
Molecules 2009, 14(6), 2016-2031; https://doi.org/10.3390/molecules14062016 - 4 Jun 2009
Cited by 519 | Viewed by 31572
Abstract
Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark. In particular the lupane-, oleanane-, and ursane triterpenes display various pharmacological effects while being devoid of prominent toxicity. Therefore, these triterpenes are promising leading compounds for the development of [...] Read more.
Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark. In particular the lupane-, oleanane-, and ursane triterpenes display various pharmacological effects while being devoid of prominent toxicity. Therefore, these triterpenes are promising leading compounds for the development of new multi-targeting bioactive agents. Screening of 39 plant materials identified triterpene rich (> 0.1% dry matter) plant parts. Plant materials with high triterpene concentrations were then used to obtain dry extracts by accelerated solvent extraction resulting in a triterpene content of 50 - 90%. Depending on the plant material, betulin (birch bark), betulinic acid (plane bark), oleanolic acid (olive leaves, olive pomace, mistletoe sprouts, clove flowers), ursolic acid (apple pomace) or an equal mixture of the three triterpene acids (rosemary leaves) are the main components of these dry extracts. They are quantitatively characterised plant extracts supplying a high concentration of actives and therefore can be used for development of phytopharmaceutical formulations. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids 2013)
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188 KiB  
Article
Application of Thermally Responsive Elastin-like Polypeptide Fused to a Lactoferrin-derived Peptide for Treatment of Pancreatic Cancer
by Iqbal Massodi, Emily Thomas and Drazen Raucher
Molecules 2009, 14(6), 1999-2015; https://doi.org/10.3390/molecules14061999 - 4 Jun 2009
Cited by 65 | Viewed by 13734
Abstract
A well characterized, peptide derivative of bovine lactoferrin, L12, has been shown to possess anticancer properties in multiple cell lines. However, adverse side effects in normal tissues and poor plasma kinetics that hinder the clinical effectiveness of current chemotherapeutics also deter the potential [...] Read more.
A well characterized, peptide derivative of bovine lactoferrin, L12, has been shown to possess anticancer properties in multiple cell lines. However, adverse side effects in normal tissues and poor plasma kinetics that hinder the clinical effectiveness of current chemotherapeutics also deter the potential for effective delivery of this L12 peptide. To overcome these limitations, we have developed an Elastin-like polypeptide (ELP) carrier that has the potential to thermally target therapeutic peptides and chemotherapeutics to a tumor site. The coding sequence of ELP was modified with the L12 peptide at the C-terminus and a membrane transduction domain derived from the HIV-1 Tat protein at the N-terminus (Tat-ELP-L12). The thermally responsive Tat-ELP1-L12 is soluble in aqueous solutions at 37°C but aggregates near 41°C, which makes Tat-ELP1-L12 ideal for targeting to solid tumors on application of focused hyperthermia. We observed that under hyperthermia conditions at 42°C, Tat-ELP1-L12 mediated cytotoxicity in MIA PaCa-2 pancreatic adenocarcinoma cells was enhanced by nearly thirty-fold. We investigated the mechanisms of cell death and found evidence of mitochondrial membrane depolarization and caspase activation, which are characteristic of apoptosis, as well as, increased membrane permeability, as shown by LDH release. These results suggest that Tat-ELP1-L12 possesses cytotoxic properties to cancer cells in vitro and may have the potential to provide an effective vehicle to thermally target solid tumors. Full article
(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutics)
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212 KiB  
Article
Chemical Composition and Antibacterial Activity of the Essential Oils of Callistemon citrinus and Callistemon viminalis from South Africa
by Opeoluwa O. Oyedeji, Oladipupo. A. Lawal, Francis. O. Shode and Adebola. O. Oyedeji
Molecules 2009, 14(6), 1990-1998; https://doi.org/10.3390/molecules14061990 - 2 Jun 2009
Cited by 106 | Viewed by 15701
Abstract
The chemical composition and the antibacterial activity of the essential oils obtained by hydrodistillation from the leaves of Callistemon citrinus and Callistemon viminalis were analyzed by GC and GC/MS. Twenty-four and twelve components were identified for C. citrinus and C. viminalis, representing [...] Read more.
The chemical composition and the antibacterial activity of the essential oils obtained by hydrodistillation from the leaves of Callistemon citrinus and Callistemon viminalis were analyzed by GC and GC/MS. Twenty-four and twelve components were identified for C. citrinus and C. viminalis, representing 92.0% and 98.3% of the total oils. The major components of C. citrinus and C. viminalis were 1,8-cineole (61.2% and 83.2%) and α-pinene (13.4% and 6.4%), respectively. The in vitro antibacterial activity of the essential oils was studied against 12 bacteria strains using disc diffusion and broth microdilution methods. The oils exhibited strong zone of inhibitions against some bacteria such as S. faecalis (20.3-24.0 mm), both strains of S. aureus (23.0-26.3 mm), B. cereus (17.3-19.0 mm) and S. macrcesens (11.3-23.7 mm) when compared to standard antibiotics gentamycin and tetracycline used as controls. Expect for P. aeruginosa and S. macrcescens, the MIC values of both essential oils ranged from 0.31-2.50 mg/mL. Full article
108 KiB  
Communication
Chemical Analysis of the Resinous Exudate Isolated from Heliotropium taltalense and Evaluation of the Antioxidant Activity of the Phenolics Components and the Resin in Homogeneous and Heterogeneous Systems
by Brenda Modak, Macarena Rojas and René Torres
Molecules 2009, 14(6), 1980-1989; https://doi.org/10.3390/molecules14061980 - 2 Jun 2009
Cited by 31 | Viewed by 10882
Abstract
H. taltalense (Phil.) Johnst. (Heliotropiaceae) is an endemic species of the northern coast of Chile that produces a resinous exudate that covers its foliar surface and stems. Its chemical composition was analyzed for the first time, and two aromatic geranyl derivatives: filifolinol and [...] Read more.
H. taltalense (Phil.) Johnst. (Heliotropiaceae) is an endemic species of the northern coast of Chile that produces a resinous exudate that covers its foliar surface and stems. Its chemical composition was analyzed for the first time, and two aromatic geranyl derivatives: filifolinol and filifolinyl senecionate and three flavonoids – naringenin, 3-O-methylgalangin and 7-O-methyleriodictiol – were isolated. The antioxidant activity of the flavonoids and the resinous exudates was carried out by measuring the 1,1-diphenyl-2-picrylhydrazyl (DPPH) bleaching effect in ethanolic solution and in sodium dodecyl sulfate (SDS) micelles. The influence of the reaction medium was analyzed. The initial velocity reactions for the pure compounds and for the extract were higher in SDS media than in ethanolic solution. The velocity of reaction observed was interpreted in terms of the reaction medium environment in the micelle. Full article
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