Molecules

502 KiB

Open AccessArticle

Synthesis of New Azo Compounds Based on N-(4-Hydroxypheneyl)maleimide and N-(4-Methylpheneyl)maleimide

by Issam Ahmed Mohammed and Asniza Mustapha

Molecules 2010, 15(10), 7498-7508; https://doi.org/10.3390/molecules15107498 - 25 Oct 2010

Cited by 54 | Viewed by 11526

Maleic anhydride was reacted with p-aminophenol and p-toluidine in the presence of di-phosphorus pentoxide (P₂O₅) as a catalyst to produce two compounds: N-(4-hydroxy-phenyl)maleimide (I) and N-(4-methylphenyl)maleimide (II). The new azo compounds [...] Read more.

Maleic anhydride was reacted with p-aminophenol and p-toluidine in the presence of di-phosphorus pentoxide (P₂O₅) as a catalyst to produce two compounds: N-(4-hydroxy-phenyl)maleimide (I) and N-(4-methylphenyl)maleimide (II). The new azo compounds I(a-c) and II(a-c) were prepared by the reaction of I and II with three different aromatic amines, namely aniline, p-aminophenol and p-toluidine. The structures of these compounds were confirmed by CHN, FT-IR, ¹H-NMR, ¹³C-NMR, mass spectrum and UV/Vis spectroscopy. Full article

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224 KiB

Open AccessArticle

Lead Contamination in Selected Foods from Riyadh City Market and Estimation of the Daily Intake

by Zeid A. Al Othman

Molecules 2010, 15(10), 7482-7497; https://doi.org/10.3390/molecules15107482 - 25 Oct 2010

Cited by 39 | Viewed by 9501

Abstract

This study was carried out to determine lead contamination in 104 of the representative food items in the Saudi diet and to estimate the dietary lead intake of Saudi Arabians. Three samples of each selected food items were purchased from the local markets [...] Read more.

This study was carried out to determine lead contamination in 104 of the representative food items in the Saudi diet and to estimate the dietary lead intake of Saudi Arabians. Three samples of each selected food items were purchased from the local markets of Riyadh city, the capital of Saudi Arabia. Each pooled sample was analyzed in triplicate by ICP-AES after thorough homogenization. Sweets (0.011–0.199 μg/g), vegetables (0.002–0.195 μg/g), legumes (0.014–0.094 μg/g), eggs (0.079 μg/g), meat and meat products (0.013–0.068 μg/g) were the richest sources of lead. Considering the amounts of each food consumed, the major food sources of lead intake for Saudi can be arranged as follows: vegetables (25.4%), cereal and cereal products (24.2%), beverages (9.7%) sweets (8.2%), legumes (7.4%), fruits (5.4%) milk and milk products (5.1%). The daily intake of lead was calculated taking into account the concentration of this element in the edible part of the daily consumption data which were derived from two sources, (a) the KSA food sheet provided by the Food and Agriculture Organization (FAO) and (b) from questionnaires distributed among 300 families in Riyadh city. The results showed that the daily intakes of lead according to the two sources are 22.7 and 24.5 μg/person/day respectively, which are lower than that mentioned by The Joint Expert Committee on Food Additives (JECFA), whereas it is comprabale with that of other countries. Full article

117 KiB

Open AccessArticle

Synthesis of Novel 1-[(2,6-Dichloro-4-trifluoromethyl)phenyl]-3-aryl-1H-pyrazole-4-carbaldehydes

by Huanan Hu, Changhua Ge, Lisheng Ding and Anjiang Zhang

Molecules 2010, 15(10), 7472-7481; https://doi.org/10.3390/molecules15107472 - 25 Oct 2010

Cited by 19 | Viewed by 7322

Abstract

A series of novel 1-[(2,6-dichloro-4-trifluoromethyl)phenyl]-3-aryl-1H-pyrazole-4-carbaldehydes 6a-i were synthesized using the Vilsmeier-Haack reagent. The structures of all the title compounds have been confirmed by elemental analysis, ¹H-NMR and ¹³C-NMR and in addition, the structure of intermediate 5b was investigated by X-ray crystallography. Full article

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137 KiB

Open AccessArticle

A New Natural Ceramide from Trollius chinensis Bunge

by Ru-Feng Wang, Rui-Ning Liu, Tong Zhang and Tao Wu

Molecules 2010, 15(10), 7467-7471; https://doi.org/10.3390/molecules15107467 - 25 Oct 2010

Cited by 15 | Viewed by 7853

Abstract

A new natural product named trolliamide was isolated from Trollius chinensis Bunge. Its structure was determined as 2-hydroxy-tetracosanoic acid(2,3-dihydroxy-1-hydroxymethyl-heptadec-7-enyl)-amide by spectroscopic methods, including UV, IR, MS and NMR. This is the first report of a ceramide isolated from Trollius chinensis. Full article

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181 KiB

Open AccessArticle

Creation of a Databank for Content of Antioxidants in Food Products by an Amperometric Method

by Yakov I. Yashin, Boris V. Nemzer, Vadim Yu. Ryzhnev, Alexandr Ya. Yashin, Nina I. Chernousova and Polina A. Fedina

Molecules 2010, 15(10), 7450-7466; https://doi.org/10.3390/molecules15107450 - 22 Oct 2010

Cited by 27 | Viewed by 11273

Abstract

Oxidative stress, i.e. excessive content of reactionary, oxygen, and nitrogen compounds (ROAC), including free radicals, is one of the causes of various dangerous diseases as well as premature aging. The adverse effect of free radicals can be neutralized by antioxidants. In order to [...] Read more.

Oxidative stress, i.e. excessive content of reactionary, oxygen, and nitrogen compounds (ROAC), including free radicals, is one of the causes of various dangerous diseases as well as premature aging. The adverse effect of free radicals can be neutralized by antioxidants. In order to carry out antioxidant therapy, one needs to know the contents of antioxidants in food products. We have created the databank for the contents of antioxidants in 1,140 food products, beverages, etc. Apart from water-soluble antioxidants, fat-soluble antioxidants in dairy and fish products, cacao, chocolate, nuts etc. were determined for the first time using an amperometric method. Full article

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Open AccessArticle

Prenylated Xanthones from the Bark of Garcinia xanthochymus and Their 1,1-Diphenyl-2-picrylhydrazyl (DPPH) Radical Scavenging Activities

by Yu Chen, Hua Fan, Guang-zhong Yang, Yan Jiang, Fang-fang Zhong and Hong-wu He

Molecules 2010, 15(10), 7438-7449; https://doi.org/10.3390/molecules15107438 - 22 Oct 2010

Cited by 27 | Viewed by 10996

Abstract

Garcinia xanthochymus has been widely used in traditional Chinese medicine for expelling worms and removing food toxins. Bioassay-guided fractionation of an EtOAc-soluble extract of G. xanthochymus stem bark led to the isolation of six new xanthones. Their structures were elucidated by spectroscopic methods, [...] Read more.

Garcinia xanthochymus has been widely used in traditional Chinese medicine for expelling worms and removing food toxins. Bioassay-guided fractionation of an EtOAc-soluble extract of G. xanthochymus stem bark led to the isolation of six new xanthones. Their structures were elucidated by spectroscopic methods, especially 2D-NMR techniques. Free-radical-scavenging activities of the isolated compounds were elucidated through DPPH method. Most of the isolated compounds showed considerable free radical scavenging activity on DPPH assay. Compound 1 exhibited effective antioxidant scavenging activity against DPPH radical with an IC₅₀ value of 19.64 μM, and compound 6 showed the lowest activity among all the tested molecules, with an IC₅₀ value of 66.88 μM. These findings support the notion that the plant genus Garcinia is a good source of bioactive compounds. Full article

(This article belongs to the Section Natural Products Chemistry)

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226 KiB

Open AccessArticle

One-Pot Synthesis of 2,3,4-Triarylquinolines via Suzuki-Miyaura Cross-Coupling of 2-Aryl-4-chloro-3-iodoquinolines with Arylboronic Acids

by Malose Jack Mphahlele and Mamasegare Mabel Mphahlele

Molecules 2010, 15(10), 7423-7437; https://doi.org/10.3390/molecules15107423 - 22 Oct 2010

Cited by 10 | Viewed by 6258

Abstract

Palladium–catalyzed Suzuki cross-coupling of 2-aryl-4-chloro-3-iodoquinolines with excess arylboronic acids (2.5 equiv.) in the presence of tricyclohexylphosphine afforded the 2,3,4-triarylquinolines in one-pot operation. The incipient 2,3-diaryl-4-chloroquinolines were also prepared and transformed to the primary 4-amino-2,3-diarylquinolines and 2,3-diarylquinolin-4(1H)-ones. Full article

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Open AccessArticle

Evaluation on Anti-hepatitis Viral Activity of Vitis vinifer L

by Tao Liu, Jun Zhao, Haibo Li and Long Ma

Molecules 2010, 15(10), 7415-7422; https://doi.org/10.3390/molecules15107415 - 22 Oct 2010

Cited by 15 | Viewed by 9210

Abstract

Suosuo grape (Vitis vinifer L) is traditionally used as a therapeutic agent for measles and hepatitis by the ethnic Uighurs. This work aimed to investigate the anti-HBV effect of total triterpene (VTT), total flavonoids (VTF) and total polysaccharides (VTP) from Suosuo grape, [...] Read more.

Suosuo grape (Vitis vinifer L) is traditionally used as a therapeutic agent for measles and hepatitis by the ethnic Uighurs. This work aimed to investigate the anti-HBV effect of total triterpene (VTT), total flavonoids (VTF) and total polysaccharides (VTP) from Suosuo grape, and their synergistic effects were also tested. The viral antigens of cellular secretion, HBsAg and HBeAg, were determined by enzyme linked immunosorbent assay (ELISA).The quantity of HBV-DNA released in the supernatant was assayed by real-time PCR. It was found that it effectively suppressed the secretion of HBsAg and HBeAg from HepG2.2.15 cells in a dose-dependent manner, as well as the HBV DNA. The results of orthogonal design experiment showed that the combination of VTT 20 μg/mL, VTF 50 μg/mL and VTP 50 μg/mL had the best optimistic inhibitory effects on HBeAg secretion. Full article

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Open AccessArticle

The Pharmacological Effects of Morroniside and Loganin Isolated from Liuweidihuang Wan, on MC3T3-E1 Cells

by Manyu Li, Wei Wang, Ping Wang, Kun Yang, Hui Sun and Xijun Wang

Molecules 2010, 15(10), 7403-7414; https://doi.org/10.3390/molecules15107403 - 21 Oct 2010

Cited by 55 | Viewed by 11017

Abstract

Liuweidihuang Wan (LW), initially a well-known formula for curing “wu chi wu ruan”, is commonly used nowadays for clinical treatment of Postmenopausal Osteoporosis (PO), but the identity of the effective substance(s) remains unclear. The present study was designed to evaluate the effects of [...] Read more.

Liuweidihuang Wan (LW), initially a well-known formula for curing “wu chi wu ruan”, is commonly used nowadays for clinical treatment of Postmenopausal Osteoporosis (PO), but the identity of the effective substance(s) remains unclear. The present study was designed to evaluate the effects of morroniside and loganin isolated from LW on the proliferation, differentiation and apoptosis of MC3T3-E1 cells, as well as the possible mechanism of action. Morroniside and loganin had no effects on the proliferation of MC3T3-E1 cells, but both susbtances could improve the activity of alkaline phosphatase (ALP), and increase the contents of collagen type I and osteocalcin. Simultaneously, the mRNA expression of caspase-3, capase-9, RANKL was down-regulated and that of bcl-2 was up-regulated, which partially explains the anti-osteoporosis mechanism in MC3T3-E1 cells. In conclusion, morroniside and loganin may directly promote the differentiation and inhibit the apoptosis of MC3T3-E1 cells, and accordingly indirectly reduce bone resorption, which makes them promising natural drugs leads for treating PO in the near future. Full article

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Open AccessArticle

Antibacterial Activity of Phytochemicals Isolated from Atractylodes japonica against Methicillin-Resistant Staphylococcus aureus

by Seung-Il Jeong, Seon-Young Kim, Sang-Jun Kim, Byung-Soon Hwang, Tae-Ho Kwon, Kang-Yeol Yu, Seung-Ho Hang, Koji Suzuki and Kang-Ju Kim

Molecules 2010, 15(10), 7395-7402; https://doi.org/10.3390/molecules15107395 - 21 Oct 2010

Cited by 36 | Viewed by 10913

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has been emerging worldwide as one of the most important problems in communities and hospitals. Therefore, new agents are needed to treat acute oral infections from MRSA. In this study, antibacterial compounds from the roots of Atractylodes japonica ( [...] Read more.

Methicillin-resistant Staphylococcus aureus (MRSA) has been emerging worldwide as one of the most important problems in communities and hospitals. Therefore, new agents are needed to treat acute oral infections from MRSA. In this study, antibacterial compounds from the roots of Atractylodes japonica (A. japonica) were isolated and characterized. The compounds were isolated from the root extracts using HPLC-piloted activity-guided fractionations. Four A. japonica compounds were isolated and identified as atractylenolide III (1), atractylenolide I (2), diacetylatractylodiol [(6E,12E)-tetradeca-6,12-diene-8,10-diyne-1,3-diol diacetate, TDEYA, 3). and (6E,12E)-tetradecadiene-8,10-diyne-1,3-diol (TDEA, 4), which was obtained by hydrolysis of TDEYA. The minimum inhibitory concentrations (MICs) was determined in the setting of clinical MRSA isolates. Compound 4 showed anti-MRSA activity with a MIC value of 4-32 μg/mL. The overall results provide promising baseline information for the potential use of the extract of A. japonica as well as some of the isolated compounds in the treatment of bacterial infections. Full article

(This article belongs to the Collection Bioactive Compounds)

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212 KiB

Open AccessArticle

Synthesis, Gastroprotective Effect and Cytotoxicity of New Amino Acid Diterpene Monoamides and Diamides

by Guillermo Schmeda-Hirschmann, Mariano Walter Pertino, Jaime A. Rodriguez, Francisco Monsalve, Daniel Droguett and Cristina Theoduloz

Molecules 2010, 15(10), 7378-7394; https://doi.org/10.3390/molecules15107378 - 21 Oct 2010

Cited by 7 | Viewed by 10768

Abstract

Following our studies on the gastroprotective effect and cytotoxicity of terpene derivatives, new amides were prepared from the diterpene 8(17)-labden-15,19-dioic acid (junicedric acid) and its 8(9)-en isomer with C-protected amino acids (amino acid esters). The new compounds were evaluated for their gastroprotective effect [...] Read more.

Following our studies on the gastroprotective effect and cytotoxicity of terpene derivatives, new amides were prepared from the diterpene 8(17)-labden-15,19-dioic acid (junicedric acid) and its 8(9)-en isomer with C-protected amino acids (amino acid esters). The new compounds were evaluated for their gastroprotective effect in the ethanol/HCl-induced gastric lesions model in mice, as well as for cytotoxicity using the following human cell lines: normal lung fibroblasts (MRC-5), gastric adenocarcinoma cells (AGS) and liver hepatocellular carcinoma (Hep G2). A dose-response experiment showed that at 25 mg/kg the C-15 leucyl and C-15,19-dileucylester amides of junicedric acid reduced gastric lesions by about 65.6 and 49.6%, respectively, with an effect comparable to lansoprazole at 20 mg/kg (79.3% lesion reduction). The comparison of the gastroprotective effect of 18 new amino acid ester amides was carried out at a single oral dose of 25 mg/kg. Several compounds presented a strong gastroprotective effect, reducing gastric lesions in the 70.9-87.8% range. The diprolyl derivative of junicedric acid, the most active product of this study (87.8% lesion reduction at 25 mg/kg) presented a cytotoxicity value comparable with that of the reference compound lansoprazole. The structure-activity relationships are discussed. Full article

(This article belongs to the Section Medicinal Chemistry)

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667 KiB

Open AccessArticle

Chemometric Studies on Natural Products as Potential Inhibitors of the NADH Oxidase from Trypanosoma cruzi Using the VolSurf Approach

by Luciana Scotti, Elizabeth Igne Ferreira, Marcelo Sobral da Silva and Marcus Tullius Scotti

Molecules 2010, 15(10), 7363-7377; https://doi.org/10.3390/molecules15107363 - 21 Oct 2010

Cited by 42 | Viewed by 11564

Abstract

Natural products have widespread biological activities, including inhibition of mitochondrial enzyme systems. Some of these activities, for example cytotoxicity, may be the result of alteration of cellular bioenergetics. Based on previous computer-aided drug design (CADD) studies and considering reported data on structure-activity relationships [...] Read more.

Natural products have widespread biological activities, including inhibition of mitochondrial enzyme systems. Some of these activities, for example cytotoxicity, may be the result of alteration of cellular bioenergetics. Based on previous computer-aided drug design (CADD) studies and considering reported data on structure-activity relationships (SAR), an assumption regarding the mechanism of action of natural products against parasitic infections involves the NADH-oxidase inhibition. In this study, chemometric tools, such as: Principal Component Analysis (PCA), Consensus PCA (CPCA), and partial least squares regression (PLS), were applied to a set of forty natural compounds, acting as NADH-oxidase inhibitors. The calculations were performed using the VolSurf+ program. The formalisms employed generated good exploratory and predictive results. The independent variables or descriptors having a hydrophobic profile were strongly correlated to the biological data. Full article

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

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184 KiB

Open AccessArticle

Tetrabutylammonium Bromide Media Aza-Michael Addition of 1,2,3,6-Tetrahydrophthalimide to Symmetrical Fumaric Esters and Acrylic Esters under Solvent-Free Conditions

by Gholamhassan Imanzadeh, Farzaneh Ahmadi, Mohammadreza Zamanloo and Yagoub Mansoori

Molecules 2010, 15(10), 7353-7362; https://doi.org/10.3390/molecules15107353 - 21 Oct 2010

Cited by 19 | Viewed by 11243

Abstract

The aza-Michael addition of 1,2,3,6-tetrahydrophthalimide with symmetrical fumaric esters has been performed efficiently in a solvent-free system at 100 °C and using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a base in the presence of tetrabutylammonium bromide (TBAB). The products were obtained in good to high yields [...] Read more.

The aza-Michael addition of 1,2,3,6-tetrahydrophthalimide with symmetrical fumaric esters has been performed efficiently in a solvent-free system at 100 °C and using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a base in the presence of tetrabutylammonium bromide (TBAB). The products were obtained in good to high yields within 2.5-7.0 h. This reaction worked well on linear alkyl fumarates and was not effective with nonlinear alkyl fumarates. Although the reaction was also applicable to acrylates such as n-butyl acrylate, methacrylates and crotonates were not suitable Michael acceptors for this reaction. Full article

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441 KiB

Open AccessReview

Plant Phenolics: Extraction, Analysis and Their Antioxidant and Anticancer Properties

by Jin Dai and Russell J. Mumper

Molecules 2010, 15(10), 7313-7352; https://doi.org/10.3390/molecules15107313 - 21 Oct 2010

Cited by 3107 | Viewed by 92163

Abstract

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such [...] Read more.

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Antioxidant-Prooxidant Properties of a New Organoselenium Compound Library

by Daniel Plano, Ylenia Baquedano, Elena Ibáñez, Iosu Jiménez, Juan Antonio Palop, Julian E. Spallholz and Carmen Sanmartín

Molecules 2010, 15(10), 7292-7312; https://doi.org/10.3390/molecules15107292 - 21 Oct 2010

Cited by 87 | Viewed by 13644

Abstract

The present study describes the biological evaluation of a library of 59 organo-selenium compounds as superoxide (O₂^─) generators and cytotoxic agents in human prostate cancer cells (PC-3) and in breast adenocarcinoma (MCF-7). In order to corroborate that the biological activity [...] Read more.

The present study describes the biological evaluation of a library of 59 organo-selenium compounds as superoxide (O₂^─) generators and cytotoxic agents in human prostate cancer cells (PC-3) and in breast adenocarcinoma (MCF-7). In order to corroborate that the biological activity for selenium compounds depends on the chemical form, a broad structural variety is presented. These structures include selenocyanates, diselenides, selenoalkyl functional moieties and eight newly synthesized symmetrically substituted dithioselenites and selenylureas. Eleven of the derivatives tested showed high levels of superoxide generation in vitro via oxidation of reduced glutathione (GSH) and nine of them were more catalytic than the reference compound, diselenodipropionic acid. Eighteen of the library compounds inhibited cell growth more than or similar to reference chemotherapeutic drugs in PC-3 and eleven were more potent cytotoxic agents than etoposide in the MCF-7 cell line. Considering both parameters (superoxide generation and cell cytotoxicity) compounds B1, C6 and C9 displayed the best therapeutic profiles. Considering that many diselenide compounds can generate superoxide (O₂^─) in vitro via oxidation of GSH and other thiols, the analogue B1, that contains a diselenide moiety, was selected for a preliminary mechanistic investigation, which . revealed that B1 has apoptogenic effects similar to camptothecin mediated by reactive oxygen species (ROS) in lymphocytic leukemia cells (CCRF-CEM) and affected the MCF-7 cell-cycle in G₂/M and S-phases. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview

The Nrf2 System as a Potential Target for the Development of Indirect Antioxidants

by Kyeong-Ah Jung and Mi-Kyoung Kwak

Molecules 2010, 15(10), 7266-7291; https://doi.org/10.3390/molecules15107266 - 20 Oct 2010

Cited by 396 | Viewed by 24029

Abstract

Oxidative stress causes damage to multiple cellular components such as DNA, proteins, and lipids, and is implicated in various human diseases including cancer, neurodegeneration, inflammatory diseases, and aging. In response to oxidative attack, cells have developed an antioxidant defense system to maintain cellular [...] Read more.

Oxidative stress causes damage to multiple cellular components such as DNA, proteins, and lipids, and is implicated in various human diseases including cancer, neurodegeneration, inflammatory diseases, and aging. In response to oxidative attack, cells have developed an antioxidant defense system to maintain cellular redox homeostasis and to protect cells from damage. The thiol-containing small molecules (e.g. glutathione), reactive oxygen species-inactivating enzymes (e.g. glutathione peroxidase), and phase 2 detoxifying enzymes (e.g. NAD(P)H: quinine oxidoreductase 1 and glutathione-S-transferases) are members of this antioxidant system. NF-E2-related factor 2 (Nrf2) is a CNC-bZIP transcription factor which regulates the basal and inducible expression of a wide array of antioxidant genes. Following dissociation from the cytosolic protein Keap1, a scaffolding protein which binds Nrf2 and Cul3 ubiquitin ligase for proteasome degradation, Nrf2 rapidly accumulates in the nucleus and transactivates the antioxidant response element in the promoter region of many antioxidant genes. The critical role of Nrf2 has been demonstrated by various animal studies showing that mice with a targeted disruption of the nrf2 gene are prone to develop lesions in response to environmental toxicants/carcinogens, drugs, and inflammatory insults. In this review, we discuss the role of the Nrf2 system, with particular focus on Nrf2-controlled target genes and the potential pleiotropic effects of Nrf2 activation of indirect antioxidants. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview

Protecting Groups in Carbohydrate Chemistry: Influence on Stereoselectivity of Glycosylations

by Jian Guo and Xin-Shan Ye

Molecules 2010, 15(10), 7235-7265; https://doi.org/10.3390/molecules15107235 - 20 Oct 2010

Cited by 145 | Viewed by 21585

Abstract

Saccharides are polyhydroxy compounds, and their synthesis requires complex protecting group manipulations. Protecting groups are usually used to temporarily mask a functional group which may interfere with a certain reaction, but protecting groups in carbohydrate chemistry do more than protecting groups usually do. [...] Read more.

Saccharides are polyhydroxy compounds, and their synthesis requires complex protecting group manipulations. Protecting groups are usually used to temporarily mask a functional group which may interfere with a certain reaction, but protecting groups in carbohydrate chemistry do more than protecting groups usually do. Particularly, protecting groups can participate in reactions directly or indirectly, thus affecting the stereochemical outcomes, which is important for synthesis of oligosaccharides. Herein we present an overview of recent advances in protecting groups influencing stereoselectivity in glycosylation reactions, including participating protecting groups, and conformation-constraining protecting groups in general. Full article

(This article belongs to the Special Issue Protecting Group in Organic Synthesis)

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Open AccessCommunication

Efficient Microwave-Assisted Synthesis of 5-Deazaflavine Derivatives

by Jorge Trilleras, Luis Gabriel López, Dency José Pacheco, Jairo Quiroga, Manuel Nogueras, José M. de la Torre and Justo Cobo

Molecules 2010, 15(10), 7227-7234; https://doi.org/10.3390/molecules15107227 - 20 Oct 2010

Cited by 8 | Viewed by 8867

Abstract

A series of pyrimido[4,5-b]quinolines (5-deazaflavines), were synthesized by microwave assisted intramolecular cyclization. The N⁴-substituted-2,4-diamino-6-chloro-pyrimidine-5-carbaldehydes, were prepared by selective monoamination of 2-amino-4,6-dichloropyrimidine-5-carbaldehyde with aliphatic and aromatic amines. Full article

(This article belongs to the Section Organic Chemistry)

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Open AccessArticle

Anthraquinones with Antiplasmodial Activity from the Roots of Rennellia elliptica Korth. (Rubiaceae)

by Che Puteh Osman, Nor Hadiani Ismail, Rohaya Ahmad, Norizan Ahmat, Khalijah Awang and Faridahanim Mohd Jaafar

Molecules 2010, 15(10), 7218-7226; https://doi.org/10.3390/molecules15107218 - 20 Oct 2010

Cited by 49 | Viewed by 10839

Abstract

Dichloromethane root extract of Rennellia elliptica Korth. showed strong inhibition of Plasmodium falciparum growth in vitro with an IC₅₀value of 4.04 µg/mL. A phytochemical study of the dichloromethane root extract has led to the isolation and characterization of a new anthraquinone, [...] Read more.

Dichloromethane root extract of Rennellia elliptica Korth. showed strong inhibition of Plasmodium falciparum growth in vitro with an IC₅₀value of 4.04 µg/mL. A phytochemical study of the dichloromethane root extract has led to the isolation and characterization of a new anthraquinone, 1,2-dimethoxy-6-methyl-9,10-anthraquinone (1), and ten known anthraquinones: 1-hydroxy-2-methoxy-6-methyl-9,10-anthraquinone (2), nordamnacanthal (3), 2-formyl-3-hydroxy-9,10-anthraquinone (4), damnacanthal (5), lucidin-ω-methyl ether (6), 3-hydroxy-2-methyl-9,10-anthraquinone (7), rubiadin (8), 3-hydroxy-2-methoxy-6-methyl-9,10-anthraquinone (9), rubiadin-1-methyl ether (10) and 3-hydroxy-2-hydroxymethyl-9,10-anthraquinone (11). Structural elucidation of all compounds was accomplished by modern spectroscopic methods, notably 1D and 2D NMR, IR, UV and HREIMS. The new anthraquinone 1, 2-formyl-3-hydroxy-9,10-anthraquinone (4) and 3-hydroxy-2-methyl-9,10-anthraquinone (7) possess strong antiplasmodial activity, with IC₅₀ values of 1.10, 0.63 and 0.34 µM, respectively. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

The Beneficial Effect of Vanillic Acid on Ulcerative Colitis

by Su-Jin Kim, Min-Cheol Kim, Jae-Young Um and Seung-Heon Hong

Molecules 2010, 15(10), 7208-7217; https://doi.org/10.3390/molecules15107208 - 19 Oct 2010

Cited by 136 | Viewed by 12922

Abstract

Vanillic acid, an oxidized form of vanillin, is a benzoic acid derivative used as a flavoring agent. The objective of this study was to determine whether vanillic acid has beneficial effects against dextran sulfate sodium (DSS)-induced ulcerative colitis. Our results showed that vanillic [...] Read more.

Vanillic acid, an oxidized form of vanillin, is a benzoic acid derivative used as a flavoring agent. The objective of this study was to determine whether vanillic acid has beneficial effects against dextran sulfate sodium (DSS)-induced ulcerative colitis. Our results showed that vanillic acid reduced the severity of the clinical signs of DSS-induced colitis, including weight loss and shortening of colon length, and the disease activity index. The results of this study showed that vanillic acid significantly suppressed the expression of cyclooxygenase-2 and the activation of transcription nuclear factor-kB p65 in DSS-treated colon tissues. In addition, we observed that the plasma levels of interleukin (IL)-6 were higher in the DSS-treated group than in the control group, but these increased levels were reduced by the administration of vanillic acid. Taken together, these findings suggest that vanillic acid has a beneficial effect on DSS-induced ulcerative colitis, thereby indicating its usefulness in the regulation of chronic intestinal inflammation. Full article

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Open AccessArticle

Small Interfering RNA Effectively Inhibits the Expression of SARS Coronavirus Membrane Gene at Two Novel Targeting Sites

by Ying Wang, Ying-Li Cao, Fan Yang, Yun Zhang, Shu-Hui Wang and Li Liu

Molecules 2010, 15(10), 7197-7207; https://doi.org/10.3390/molecules15107197 - 18 Oct 2010

Cited by 18 | Viewed by 10512

Abstract

Small interfering RNA (siRNA) is a class of duplex RNA molecules of 21-25 nt nucleotides in length functioning post-transcriptionally to downregulate targeted gene expression. The membrane (M) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is highly abundant during viral infections and is [...] Read more.

Small interfering RNA (siRNA) is a class of duplex RNA molecules of 21-25 nt nucleotides in length functioning post-transcriptionally to downregulate targeted gene expression. The membrane (M) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is highly abundant during viral infections and is a critical element for viral assembly. Nucleotide substitution in the viral genome occurs frequently during SARS-CoV infection. In the current study, we analyzed the M gene sequences derived from 15 SARS-CoV isolates and uncovered six nucleotide substitutions among these isolates. Interestingly, these nucleotide substitutions are all located at the 5’ half of the M gene. Based on this information and previous reports, we created two novel siRNAs targeting two unexploited and well conserved regions in the M gene. The effects of these two siRNAs were tested by semi-quantitative RT-PCR and EGFP-M fusion gene expression. The results demonstrated that both siRNAs effectively and specifically blocked the targeted gene expression. Real time quantitative RT-PCR (qRT-PCR) revealed that siRNA targeting the 3’ half of the M gene (si-M2) induced more potent inhibition than that targeting the 5’ half (si-M1). Both si-M1 and si-M2 significantly downregulated M gene mediated upregulation of interferon b expression. Thus, our results indicate that SARS-CoV M gene specific siRNA might function in a sequence-dependent manner. Full article

(This article belongs to the Special Issue Catalytic Nucleic Acids)

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Open AccessArticle

Preparation of a Carbon-Based Solid Acid Catalyst by Sulfonating Activated Carbon in a Chemical Reduction Process

by Xiao-Yan Liu, Miao Huang, Hai-Long Ma, Zeng-Qiang Zhang, Jin-Ming Gao, Yu-Lei Zhu, Xiao-Jin Han and Xiang-Yun Guo

Molecules 2010, 15(10), 7188-7196; https://doi.org/10.3390/molecules15107188 - 18 Oct 2010

Cited by 315 | Viewed by 20109

Abstract

Sulfonated (SO₃H-bearing) activated carbon (AC-SO₃H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO₃H density of 0.64 mmol·g^-1 and a specific surface area of 602 m²·g^-1. [...] Read more.

Sulfonated (SO₃H-bearing) activated carbon (AC-SO₃H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO₃H density of 0.64 mmol·g^-1 and a specific surface area of 602 m²·g^-1. The catalytic properties of AC-SO₃H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with AC-SO₃H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO₃H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g^-1). However, AC-SO₃H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO₃H is the leaching of SO₃H group during the reactions. Full article

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Open AccessReview

Role of Oxidant Scavengers in the Prevention of Ca²⁺ Homeostasis Disorders

by Carmen Galan, Isaac Jardín, Natalia Dionisio, Ginés Salido and Juan A. Rosado

Molecules 2010, 15(10), 7167-7187; https://doi.org/10.3390/molecules15107167 - 15 Oct 2010

Cited by 20 | Viewed by 10668

Abstract

A number of disorders, such as Alzheimer disease and diabetes mellitus, have in common the alteration of the redox balance, resulting in an increase in reactive oxygen species (ROS) generation that might lead to the development of apoptosis and cell death. It has [...] Read more.

A number of disorders, such as Alzheimer disease and diabetes mellitus, have in common the alteration of the redox balance, resulting in an increase in reactive oxygen species (ROS) generation that might lead to the development of apoptosis and cell death. It has long been known that ROS can significantly alter Ca²⁺ mobilization, an intracellular signal that is involved in the regulation of a wide variety of cellular functions. Cells have a limited capability to counteract the effects of oxidative stress, but evidence has been provided supporting the beneficial effects of exogenous ROS scavengers. Here, we review the effects of oxidative stress on intracellular Ca²⁺ homeostasis and the role of antioxidants in the prevention and treatment of disorders associated to abnormal Ca²⁺ mobilization induced by ROS. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Mechanisms of the Gastric Antiulcerogenic Activity of Anacardium humile St. Hil on Ethanol-Induced Acute Gastric Mucosal Injury in Rats

by Anderson Luiz-Ferreira, Ana Cristina Alves de Almeida, Maíra Cola, Victor Barbastefano, Ana Beatriz Albino de Almeida, Leônia Maria Batista, Elisângela Farias-Silva, Cláudia Helena Pellizzon, Clélia Akiko Hiruma-Lima, Lourdes Campaner Santos, Wagner Vilegas and Alba Regina Monteiro Souza Brito

Molecules 2010, 15(10), 7153-7166; https://doi.org/10.3390/molecules15107153 - 15 Oct 2010

Cited by 38 | Viewed by 14808

Abstract

Leaves and bark infusions Anacardium humile St. Hil. (Anacardiaceae), known as in Brazil as “cajuzinho do cerrado”, have been used in folk medicine as an alternative treatment for ulcers and gastritis. This study evaluated the gastroprotective activity of an ethyl acetate extract of [...] Read more.

Leaves and bark infusions Anacardium humile St. Hil. (Anacardiaceae), known as in Brazil as “cajuzinho do cerrado”, have been used in folk medicine as an alternative treatment for ulcers and gastritis. This study evaluated the gastroprotective activity of an ethyl acetate extract of the leaves of A. humile (AcF) and the mechanism involved in this gastroprotection. Pretreatment concentrations (50, 100, 200 mg.kg⁻¹) were administered by gavage. Following a 60 min. period, all the rats were orally administered 1 mL of absolute ethanol. One hour after the administration of ethanol, all groups were sacrificed, and the gastric ulcer index was calculated. Prostaglandin PGE₂ concentration, gastric adherent mucous, and the participation of nitric oxide (NO) and sulfhydryl compounds in the gastroprotection process were also analyzed using the most effective tested dose (50 mg·kg⁻¹). A histological study of the glandular stomach for the evaluation of the epithelial damage and mucus content was also performed. AcF significantly reduced the gastric damage produced by ethanol. This effect was statistically significant for the 50 mg·kg⁻¹ group compared to control. Also, it significantly increased the PGE₂ (by 10-fold) and mucous production, while pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) or N-ethylmaleimide (NEM) completely abolished the gastroprotection. AcF has a protective effect against ethanol, and this effect, might be due to the augmentation of the protective mechanisms of mucosa. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

Anti-Adhesive Activities of Flavan-3-ols and Proanthocyanidins in the Interaction of Group A-Streptococci and Human Epithelial Cells

by Aneta Janecki and Herbert Kolodziej

Molecules 2010, 15(10), 7139-7152; https://doi.org/10.3390/molecules15107139 - 15 Oct 2010

Cited by 33 | Viewed by 11171

Abstract

Bacterial adhesion to epithelial cells is a key step in infections, allowing subsequent colonization, invasion and internalization of pathogens into tissues. Anti-adhesive agents are therefore potential prophylactic tools against bacterial infections. The range of anti-adhesive compounds is largely confined to carbohydrate analogues. Tannins [...] Read more.

Bacterial adhesion to epithelial cells is a key step in infections, allowing subsequent colonization, invasion and internalization of pathogens into tissues. Anti-adhesive agents are therefore potential prophylactic tools against bacterial infections. The range of anti-adhesive compounds is largely confined to carbohydrate analogues. Tannins are generously recognized as potent antimicrobials, but little data exist on their anti-adherence potency. Using a model for mucosal pathogenesis with labeled group A-streptococci (GAS) and human laryngeal HEp-2 cells, a series of flavan-3-ols (epicatechin, epigallocatechin, epigallocatechin-3-O-gallate) and highly purified and chemically characterized proanthocyanidin samples including procyanidins based on epicatechin, catechin or ‘mixed’ constituent flavanyl units, prodelphinidins made up of (epi)gallocatechin monomeric unts as well as oligomers possessing A-type units in their molecules was evaluated for anti-adhesive effects. Reduced microbial adherence was observed exclusively for prodelphinidins, suggesting that pyrogallol-type elements, i.e., (epi)gallocatechin units are important structural features. This is the first report on structure-activity relationships regarding the anti-adhesive potency of proanthocyanidins. In addition, the structures of the first chemically defined proanthocyanidins from Pelargonium sidoides are disclosed. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

Effects of Different Maturity Stages on Antioxidant Content of Ivorian Gnagnan (Solanum indicum L.) Berries

by Denis N’Dri, Luca Calani, Teresa Mazzeo, Francesca Scazzina, Massimiliano Rinaldi, Daniele Del Rio, Nicoletta Pellegrini and Furio Brighenti

Molecules 2010, 15(10), 7125-7138; https://doi.org/10.3390/molecules15107125 - 15 Oct 2010

Cited by 34 | Viewed by 10872

Abstract

Gnagnan (Solanum indicum L.) is a spontaneous plant widely distributed in Ivory Coast. During ripening stages, Solanum indicum L. presents different colours (green, yellow and red) and is reported to contain several albeit poorly characterized antioxidant compounds. This paper describes in detail [...] Read more.

Gnagnan (Solanum indicum L.) is a spontaneous plant widely distributed in Ivory Coast. During ripening stages, Solanum indicum L. presents different colours (green, yellow and red) and is reported to contain several albeit poorly characterized antioxidant compounds. This paper describes in detail the antioxidant profile (ascorbic acid, carotenoids and polyphenols), antioxidant capacity (FRAP test and Folin-Ciocalteau assay) and the colour changes of Gnagnan berries at different ripening levels. Ascorbic acid content was similar in green and yellow berries, but significantly lower in red ones. Red berries showed a higher content of carotenoids compared to green and yellow ones. Regarding polyphenols, several phenolic acids and flavonoids were found in all berries. The content of caffeoylquinic acids, caffeic acid, flavonol glycosides and naringenin was higher in red berries, while the content of p-coumaric acid and feruloylquinic acids was similar among the three colours. The FRAP assay increased with the ripening process, whereas total polyphenols were similar among berries. Significant differences were found for the colorimetric indexes among products of different degrees of ripening. The present results show the important role of the ripening stage in increasing the antioxidant content of Gnagnan berries. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Inhibitory Effects of Resveratrol on the Epstein-Barr Virus Lytic Cycle

by Ching-Yi Yiu, Shih-Ying Chen, Li-Kwan Chang, Ya-Fang Chiu and Tsuey-Pin Lin

Molecules 2010, 15(10), 7115-7124; https://doi.org/10.3390/molecules15107115 - 14 Oct 2010

Cited by 58 | Viewed by 11735

Abstract

Reactivation of Epstein-Barr virus (EBV) from latency to the lytic cycle is required for the production of viral particles. Here, we examine the capacity of resveratrol to inhibit the EBV lytic cycle. Our results show that resveratrol inhibits the transcription of EBV immediate [...] Read more.

Reactivation of Epstein-Barr virus (EBV) from latency to the lytic cycle is required for the production of viral particles. Here, we examine the capacity of resveratrol to inhibit the EBV lytic cycle. Our results show that resveratrol inhibits the transcription of EBV immediate early genes, the expression of EBV lytic proteins, including Rta, Zta, and EA-D and reduces viron production, suggesting that this compound may be useful for preventing the proliferation of the virus. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

A New Xanthone from the Bark Extract of Rheedia acuminata and Antiplasmodial Activity of Its Major Compounds

by Guillaume Marti, Véronique Eparvier, Marc Litaudon, Philippe Grellier and Françoise Guéritte

Molecules 2010, 15(10), 7106-7114; https://doi.org/10.3390/molecules15107106 - 14 Oct 2010

Cited by 18 | Viewed by 8425

Abstract

Bioassay-guided fractionation of the ethyl acetate bark extract of Rheedia acuminata led to the isolation of the new compound 1,5,6-trihydroxy-3-methoxy-7-geranyl-xanthone (1), together with four known compounds 2-5. These compounds were tested in vitro for their antiplasmodial activity on [...] Read more.

Bioassay-guided fractionation of the ethyl acetate bark extract of Rheedia acuminata led to the isolation of the new compound 1,5,6-trihydroxy-3-methoxy-7-geranyl-xanthone (1), together with four known compounds 2-5. These compounds were tested in vitro for their antiplasmodial activity on a chloroquine-resistant strain of Plasmodium falciparum (FcB1) and for their cytotoxicity against the human diploid embryonic lung cell line MRC-5. Full article

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Open AccessReview

Bignoniaceae Metabolites as Semiochemicals

by Lucía Castillo and Carmen Rossini

Molecules 2010, 15(10), 7090-7105; https://doi.org/10.3390/molecules15107090 - 14 Oct 2010

Cited by 20 | Viewed by 10124

Abstract

Members of the family Bignoniaceae are mostly found in tropical and neo-tropical regions in America, Asia and Africa, although some of them are cultivated in other regions as ornamentals. Species belonging to this family have been extensively studied in regard to their pharmacological [...] Read more.

Members of the family Bignoniaceae are mostly found in tropical and neo-tropical regions in America, Asia and Africa, although some of them are cultivated in other regions as ornamentals. Species belonging to this family have been extensively studied in regard to their pharmacological properties (as extracts and isolated compounds). The aim of this review is to summarize the reported scientific evidence about the chemical properties as well as that of the extracts and isolated compounds from species of this family, focusing mainly in insect-plant interactions. As it is known, this family is recognized for the presence of iridoids which are markers of oviposition and feeding preference to species which have became specialist feeders. Some herbivore species have also evolved to the point of been able to sequester iridoids and use them as defenses against their predators. However, iridoids also exhibit anti-insect properties, and therefore they may be good lead molecules to develop botanical pesticides. Other secondary metabolites, such as quinones, and whole extracts have also shown potential as anti-insect agents. Full article

(This article belongs to the Special Issue Phytochemicals with Signaling, Medicinal and Therapeutic Properties)

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Open AccessArticle

Two New Alkaloids from Narcissus serotinus L.

by Natalia B. Pigni, Strahil Berkov, Abdelaziz Elamrani, Mohammed Benaissa, Francesc Viladomat, Carles Codina and Jaume Bastida

Molecules 2010, 15(10), 7083-7089; https://doi.org/10.3390/molecules15107083 - 14 Oct 2010

Cited by 20 | Viewed by 11092

Abstract

The Amaryllidaceae family is well known for the presence of an exclusive group of alkaloids with a wide range of biological activities. Narcissus serotinus L. is a plant belonging to this family and its geographical distribution is mainly located along the Mediterranean coast. [...] Read more.

The Amaryllidaceae family is well known for the presence of an exclusive group of alkaloids with a wide range of biological activities. Narcissus serotinus L. is a plant belonging to this family and its geographical distribution is mainly located along the Mediterranean coast. In the present work, specimens collected near Casablanca (Morocco) were used to study the alkaloid content of this species. Starting with 350 g of the whole plant we used standard extraction and purification procedures to obtain fractions and compounds for GC-MS and NMR analysis. As well as five known alkaloids, we isolated two new compounds: 1-O-(3´-acetoxybutanoyl)lycorine and narseronine. The latter has been previously published, but with an erroneous structure. Full article

(This article belongs to the Section Natural Products Chemistry)

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Molecules, Volume 15, Issue 10 (October 2010) – 57 articles , Pages 6678-7508

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