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Molecules, Volume 16, Issue 4 (April 2011), Pages 2743-3455

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Open AccessArticle Antioxidant Compounds from Propolis Collected in Anhui, China
Molecules 2011, 16(4), 3444-3455; https://doi.org/10.3390/molecules16043444
Received: 23 March 2011 / Revised: 12 April 2011 / Accepted: 12 April 2011 / Published: 21 April 2011
Cited by 45 | PDF Full-text (204 KB)
Abstract
The antioxidant activities of the chloroform, ethyl acetate and n-butanol extract fractions from propolis collected in Anhui, China were evaluated in this study. The ethyl acetate fraction contained the highest amount of total phenolics and total flavonoids, and showed the greatest 1,1-diphenyl-2-picrylhydrazyl
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The antioxidant activities of the chloroform, ethyl acetate and n-butanol extract fractions from propolis collected in Anhui, China were evaluated in this study. The ethyl acetate fraction contained the highest amount of total phenolics and total flavonoids, and showed the greatest 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging capacities and Ferric Reducing/Antioxidant Power (FRAP). The antioxidant activity of twenty-two compounds isolated from the ethyl acetate fraction was also evaluated using the above-mentioned three assays. The results indicated that phenolics contributed to the antioxidant activity of propolis collected in Anhui, China. Therefore, propolis collected in Anhui, China and its phenolics might be used as a natural antioxidant. Full article
Open AccessArticle Antioxidant, Total Phenolic Content and Cytotoxicity Evaluation of Selected Malaysian Plants
Molecules 2011, 16(4), 3433-3443; https://doi.org/10.3390/molecules16043433
Received: 28 February 2011 / Revised: 2 April 2011 / Accepted: 8 April 2011 / Published: 21 April 2011
Cited by 68 | PDF Full-text (100 KB) | Supplementary Files
Abstract
Aqueous and ethanol extracts of different traditional Malaysian plants (Polygonum minus, Andrographis paniculata, Curcuma xanthorrhiza, Momordica charantia and Strobilanthes crispus) were evaluated for their antioxidant properties, total phenolic content and cytotoxic activity. Antioxidant activity was evaluated by using 1,1-diphenyl-1-picrylhydrazyl (DPPH)
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Aqueous and ethanol extracts of different traditional Malaysian plants (Polygonum minus, Andrographis paniculata, Curcuma xanthorrhiza, Momordica charantia and Strobilanthes crispus) were evaluated for their antioxidant properties, total phenolic content and cytotoxic activity. Antioxidant activity was evaluated by using 1,1-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The results showed that ethanol extracts contain high antioxidant activities compared to aqueous extracts. The findings exhibited a strong correlation between antioxidant activity and the total phenol contents. In addition, all the plant extracts showed non-toxic effects against a normal human lung fibroblast cell line (Hs888Lu). Although traditionally aqueous extracts are used, we determined that ethanol extracts usually achieved better activity in the assays. Full article
(This article belongs to the Section Natural Products Chemistry)
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Open AccessArticle Proline-Catalysed Amination Reactions in Cyclic Carbonate Solvents
Molecules 2011, 16(4), 3420-3432; https://doi.org/10.3390/molecules16043420
Received: 6 April 2011 / Revised: 19 April 2011 / Accepted: 20 April 2011 / Published: 21 April 2011
Cited by 38 | PDF Full-text (214 KB)
Abstract
Propylene carbonate is shown to be an environmentally friendly and sustainable replacement for dichloromethane and acetonitrile in proline-catalysed a-hydrazinations of aldehydes and ketones. Enantioselectivities comparable to those obtained in conventional solvents or ionic liquids can be obtained, even when using a lower catalyst
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Propylene carbonate is shown to be an environmentally friendly and sustainable replacement for dichloromethane and acetonitrile in proline-catalysed a-hydrazinations of aldehydes and ketones. Enantioselectivities comparable to those obtained in conventional solvents or ionic liquids can be obtained, even when using a lower catalyst loading. Full article
(This article belongs to the Special Issue Catalytic Asymmetric Synthesis)
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Open AccessArticle Synthesis and Anticancer Activity of Some Novel Tetralin-6-yl-pyrazoline, 2-Thioxopyrimidine, 2-Oxopyridine, 2-Thioxo-pyridine and 2-Iminopyridine Derivatives
Molecules 2011, 16(4), 3410-3419; https://doi.org/10.3390/molecules16043410
Received: 7 March 2011 / Revised: 29 March 2011 / Accepted: 8 April 2011 / Published: 20 April 2011
Cited by 24 | PDF Full-text (177 KB)
Abstract
The title compounds were prepared by reaction of 6-acetyltetralin (1) with different aromatic aldehydes 2a-c, namely 2,6-dichlorobenzaldehyde, 2,6-diflouro-benzaldehyde, and 3-ethoxy-4-hydroxybenzaldehyde, to yield the corresponding a,b-unsaturated ketones 3a-c. Compound 3b was reacted with hydrazine hydrate to yield the corresponding 2-pyrazoline 4
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The title compounds were prepared by reaction of 6-acetyltetralin (1) with different aromatic aldehydes 2a-c, namely 2,6-dichlorobenzaldehyde, 2,6-diflouro-benzaldehyde, and 3-ethoxy-4-hydroxybenzaldehyde, to yield the corresponding a,b-unsaturated ketones 3a-c. Compound 3b was reacted with hydrazine hydrate to yield the corresponding 2-pyrazoline 4, while compounds 3a,b reacted with thiourea to afford the 2-thioxopyrimidine derivatives 5a,b, respectively. The reaction of 1, and the aromatic aldehydes 2a-c with ethyl cyanoacetate, 2-cyano-thioacetamide or malononitrile in the presence of ammonium acetate yielded the corresponding 2-oxopyridines 6a,b, 2-thioxopyridines 7a-c or 2-iminopyridines 8a,b, respectively. The newly prepared compounds were evaluated for anticancer activity against two human tumor cell lines. Compound 3a showed the highest potency with IC50 = 3.5 and 4.5 μg/mL against a cervix carcinoma cell line (Hela) and breast carcinoma cell line (MCF7), respectively. Full article
Open AccessArticle N-Cyanomethylnorboldine: A New Aporphine Isolated from Alseodaphne perakensis (Lauraceae)
Molecules 2011, 16(4), 3402-3409; https://doi.org/10.3390/molecules16043402
Received: 2 March 2011 / Revised: 12 April 2011 / Accepted: 18 April 2011 / Published: 20 April 2011
Cited by 7 | PDF Full-text (433 KB)
Abstract
A phytochemical study of the bark of Alseodaphne perakensis has yielded three aporphine alkaloids: the new compound N-cyanomethylnorboldine (1), and the two known alkaloids N-methyllaurotetanine (2) and norboldine (3). The isolation was achieved by
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A phytochemical study of the bark of Alseodaphne perakensis has yielded three aporphine alkaloids: the new compound N-cyanomethylnorboldine (1), and the two known alkaloids N-methyllaurotetanine (2) and norboldine (3). The isolation was achieved by chromatographic techniques and the structural elucidation was performed via spectral methods, notably 1D- and 2D-NMR, UV, IR, and HRFABMS. The vasorelaxation activity of compound 1 has been studied. Full article
Open AccessArticle Seasonal Variation of Bioactive Alkaloid Contents in Macleaya microcarpa (Maxim.) Fedde
Molecules 2011, 16(4), 3391-3401; https://doi.org/10.3390/molecules16043391
Received: 25 March 2011 / Revised: 18 April 2011 / Accepted: 18 April 2011 / Published: 20 April 2011
Cited by 17 | PDF Full-text (281 KB)
Abstract
Macleaya microcarpa (Maxim.) Fedde belongs to the genus Macleaya, family Papaveraceae. Together with the better known and more frequently studied species M. cordata (Willd.) R. Br. it is a main source of quaternary benzo[c]phenanthridine alkaloids. Using HPLC we determined the content
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Macleaya microcarpa (Maxim.) Fedde belongs to the genus Macleaya, family Papaveraceae. Together with the better known and more frequently studied species M. cordata (Willd.) R. Br. it is a main source of quaternary benzo[c]phenanthridine alkaloids. Using HPLC we determined the content of eight isoquinoline alkaloids in the aerial and underground parts of 1-, 2-, 12- and 13-year old plants and followed their changes during the vegetative period. The dominant alkaloid of all samples collected in the end of this period was allocryptopine (3.8–13.6 mg/g for aerial parts, 24.2–48.9 mg/g for underground parts). Chelerythrine, sanguinarine and protopine were also present in both parts of the plant. Additionally, measurable concentrations of chelilutine (CL), chelirubine (CR), macarpine (MA) and sanguirubine (SR) were detected in underground parts. The most important finding was that contents of CR, CL, SR and MA in the 12- and 13-year old plant roots were significantly higher (approximately 3-fold for CR, 6-fold for CL, 5-fold for SR, and at least 14-fold for MA) than in 1- or 2-year old plants. The proportion of individual alkaloids in aerial and underground parts thus changed significantly during the vegetative period. Full article
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Open AccessArticle Simple and Efficient Synthesis of Racemic 2-(tert-Butoxycarbon-ylamino)-2-methyl-3-(1H-1,2,4-triazol-1-yl)propanoic Acid, a New Derivative of β-(1,2,4-Triazol-1-yl)alanine
Molecules 2011, 16(4), 3380-3390; https://doi.org/10.3390/molecules16043380
Received: 15 March 2011 / Revised: 7 April 2011 / Accepted: 11 April 2011 / Published: 19 April 2011
Cited by 1 | PDF Full-text (390 KB)
Abstract
A simple synthetic approach to racemic N-tert-butyloxycarbonyl-2-methyl-3-(1H-1,2,4-triazol-1-yl)alanine (5) in four steps and 68% overall yield starting from oxazoline derivative 1 is reported. This synthesis involves the alkylation of 1H-1,2,4-triazole with an O-tosyloxazoline derivative,
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A simple synthetic approach to racemic N-tert-butyloxycarbonyl-2-methyl-3-(1H-1,2,4-triazol-1-yl)alanine (5) in four steps and 68% overall yield starting from oxazoline derivative 1 is reported. This synthesis involves the alkylation of 1H-1,2,4-triazole with an O-tosyloxazoline derivative, followed by an oxazoline ring-opening reaction and oxidation of the N-protected β‑aminoalcohol by potassium permanganate. Full article
(This article belongs to the Section Organic Chemistry)
Open AccessArticle Salidroside Attenuates Hydrogen Peroxide-Induced Cell Damage Through a cAMP-Dependent Pathway
Molecules 2011, 16(4), 3371-3379; https://doi.org/10.3390/molecules16043371
Received: 25 March 2011 / Revised: 8 April 2011 / Accepted: 8 April 2011 / Published: 19 April 2011
Cited by 10 | PDF Full-text (290 KB)
Abstract
Salidroside, a major component of Rhodiola rosea L., has shown various pharmacological functions, including antioxidant effects, but the signal transduction pathway of its antioxidant effects is not very clear. In this study, we found that salidroside could attenuate hydrogen peroxide (H
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Salidroside, a major component of Rhodiola rosea L., has shown various pharmacological functions, including antioxidant effects, but the signal transduction pathway of its antioxidant effects is not very clear. In this study, we found that salidroside could attenuate hydrogen peroxide (H2O2)-induced HL-7702 cell damage, inhibit H2O2-induced cytosolic free Ca2+ ([Ca2+]i) elevation, scavenge reactive oxygen species (ROS) and increase 3’-5’-cyclic adenosine monophosphate (cAMP) level in a dose-dependent manner, but it couldn’t influence 3’-5’-cyclic guanosine monophosphate (cGMP) levels. Therefore, these results indicated that the antioxidant effects of salidroside were associated with down-regulation of [Ca2+]i, ROS occur via a cAMP-dependent pathway. Full article
Open AccessArticle Antitussive Activity of Pseudostellaria heterophylla (Miq.) Pax Extracts and Improvement in Lung Function via Adjustment of Multi-Cytokine Levels
Molecules 2011, 16(4), 3360-3370; https://doi.org/10.3390/molecules16043360
Received: 7 February 2011 / Revised: 28 March 2011 / Accepted: 31 March 2011 / Published: 19 April 2011
Cited by 20 | PDF Full-text (195 KB)
Abstract
Pseudostellaria heterophylla (Miq.) Pax is one of the most widespread herbal and healthcare products in China. Extensive clinical use has shown that it has functions which “strengthens qi and generates saliva, moistens the lung and relieves cough”. The ethyl acetate fraction extracted from
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Pseudostellaria heterophylla (Miq.) Pax is one of the most widespread herbal and healthcare products in China. Extensive clinical use has shown that it has functions which “strengthens qi and generates saliva, moistens the lung and relieves cough”. The ethyl acetate fraction extracted from the roots of the plant Pseudostellaria heterophylla exhibited a dose-dependent antitussive effect between 100 to 500 mg/kg. At a dose of 400 mg/kg, the ethyl acetate fraction treatment markedly prolonged the cough latent period and reduced the number of coughs in a guinea pig model induced by citric acid. Fall lung airway resistance, rise in dynamic lung compliance, decreased serum levels of IL-8, GM-CSF, TNF-α, and ET-1 in rat model of stable phase chronic obstructive pulmonary disease induced by cigarette smoke exposure were also observed. These results suggest that ethyl acetate fraction has antitussive activity related to its improvement in lung function via attenuation of airway inflammation by adjustment of multi-cytokine levels. Full article
(This article belongs to the Section Natural Products Chemistry)
Open AccessArticle Three New Oblongolides from Phomopsis sp. XZ-01, an Endophytic Fungus from Camptotheca acuminate
Molecules 2011, 16(4), 3351-3359; https://doi.org/10.3390/molecules16043351
Received: 17 March 2011 / Revised: 1 April 2011 / Accepted: 2 April 2011 / Published: 19 April 2011
Cited by 7 | PDF Full-text (277 KB)
Abstract
Four new metabolites, including three new oblongolides named C1, P1, and X1 (1-3) and 6-hydroxyphomodiol (10), along with eight known compounds – oblongolides B (4), C (5), D (6), O (
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Four new metabolites, including three new oblongolides named C1, P1, and X1 (1-3) and 6-hydroxyphomodiol (10), along with eight known compounds – oblongolides B (4), C (5), D (6), O (7), P (8) and U (9), (3R,4aR,5S,6R)-6-hydroxy-5-methylramulosin (11), and (3R)-5-methylmellein (12) – were isolated from the endophytic fungal strain Phomopsis sp. XZ-01 of Camptotheca acuminate. Their structures were elucidated by spectroscopic analyses, including 1H- and 13C-NMR, 2D NMR (HSQC, HMBC, 1H-1H COSY and NOESY) and HR-FT-MS. Cytotoxic activities of these compounds were evaluated. Some of them showed weak selective activities. Full article
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Open AccessArticle Identification of Diterpenoid Alkaloids from the Roots of Aconitum kusnezoffii Reihcb.
Molecules 2011, 16(4), 3345-3350; https://doi.org/10.3390/molecules16043345
Received: 22 February 2011 / Revised: 26 March 2011 / Accepted: 30 March 2011 / Published: 19 April 2011
Cited by 10 | PDF Full-text (140 KB) | Supplementary Files
Abstract
Three diterpenoid alkaloids, including an unreported compound, were isolated from the roots of Aconitum kusnezoffii Reichb. On the basis of spectral analysis, these three compounds were determined to be 1,15-dimethoxy-3-hydroxy-14-benzoyl-16-ketoneoline, benzoylaconine and aconitine. Full article
(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)
Open AccessArticle Kaempferol and Kaempferol Rhamnosides with Depigmenting and Anti-Inflammatory Properties
Molecules 2011, 16(4), 3338-3344; https://doi.org/10.3390/molecules16043338
Received: 24 March 2011 / Revised: 14 April 2011 / Accepted: 15 April 2011 / Published: 18 April 2011
Cited by 30 | PDF Full-text (444 KB)
Abstract
The objective of this study was to examine the biological activity of kaempferol and its rhamnosides. We isolated kaempferol (1), a-rhamnoisorobin (2), afzelin (3), and kaempferitrin (4) as pure compounds by far-infrared (FIR) irradiation of
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The objective of this study was to examine the biological activity of kaempferol and its rhamnosides. We isolated kaempferol (1), a-rhamnoisorobin (2), afzelin (3), and kaempferitrin (4) as pure compounds by far-infrared (FIR) irradiation of kenaf (Hibiscus cannabinus L.) leaves. The depigmenting and anti-inflammatory activity of the compounds was evaluated by analyzing their structure-activity relationships. The order of the inhibitory activity with regard to depigmentation and nitric oxide (NO) production was kaempferol (1) > a-rhamnoisorobin (2) > afzelin (3) > kaempferitrin (4). However, a-rhamnoisorobin (2) was more potent than kaempferol (1) in NF-kB-mediated luciferase assays. From these results, we conclude that the 3-hydroxyl group of kaempferol is an important pharmacophore and that additional rhamnose moieties affect the biological activity negatively. Full article
Open AccessReview Two-Photon Polarization Dependent Spectroscopy in Chirality: A Novel Experimental-Theoretical Approach to Study Optically Active Systems
Molecules 2011, 16(4), 3315-3337; https://doi.org/10.3390/molecules16043315
Received: 2 March 2011 / Revised: 7 April 2011 / Accepted: 12 April 2011 / Published: 18 April 2011
Cited by 16 | PDF Full-text (1267 KB)
Abstract
Many phenomena, including life itself and its biochemical foundations are fundamentally rooted in chirality. Combinatorial methodologies for catalyst discovery and optimization remain an invaluable tool for gaining access to enantiomerically pure compounds in the development of pharmaceuticals, agrochemicals, and flavors. Some exotic metamaterials
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Many phenomena, including life itself and its biochemical foundations are fundamentally rooted in chirality. Combinatorial methodologies for catalyst discovery and optimization remain an invaluable tool for gaining access to enantiomerically pure compounds in the development of pharmaceuticals, agrochemicals, and flavors. Some exotic metamaterials exhibiting negative refractive index at optical frequencies are based on chiral structures. Chiroptical activity is commonly quantified in terms of circular dichroism (CD) and optical rotatory dispersion (ORD). However, the linear nature of these effects limits their application in the far and near-UV region in highly absorbing and scattering biological systems. In order to surmount this barrier, in recent years we made important advancements on a novel non linear, low-scatter, long-wavelength CD approach called two-photon absorption circular dichroism (TPACD). Herein we present a descriptive analysis of the optics principles behind the experimental measurement of TPACD, i.e., the double L-scan technique, and its significance using pulsed lasers. We also make an instructive examination and discuss the reliability of our theoretical-computational approach, which uses modern analytical response theory, within a Time-Dependent Density Functional Theory (TD-DFT) approach. In order to illustrate the potential of this novel spectroscopic tool, we first present the experimental and theoretical results obtained in C2-symmetric, axially chiral R-(+)-1,1'-bi(2-naphthol), R-BINOL, a molecule studied at the beginning of our investigation in this field. Next, we reveal some preliminary results obtained for (R)-3,3′-diphenyl-2,2′-bi-1-naphthol, R-VANOL, and (R)-2,2′-diphenyl-3,3′-(4-biphenanthrol), R-VAPOL. This family of optically active compounds has been proven to be a suitable model for the structure-property relationship study of TPACD, because its members are highly conjugated yet photo-stable, and easily derivatized at the 5- and 6-positions. With the publication of these outcomes we hope to motivate more members of the scientist community to engage in state-of-the-art TPACD spectroscopy. Full article
(This article belongs to the Special Issue Chiroptical Techniques)
Open AccessReview From Polymer to Small Organic Molecules: A Tight Relationship between Radical Chemistry and Solid-Phase Organic Synthesis
Molecules 2011, 16(4), 3252-3314; https://doi.org/10.3390/molecules16043252
Received: 8 March 2011 / Revised: 28 March 2011 / Accepted: 11 April 2011 / Published: 18 April 2011
Cited by 7 | PDF Full-text (688 KB)
Abstract
Since Gomberg’s discovery of radicals as chemical entities, the interest around them has increased through the years. Nowadays, radical chemistry is used in the synthesis of 75% of all polymers, inevitably establishing a close relationship with Solid-Phase Organic Synthesis. More recently, the interest
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Since Gomberg’s discovery of radicals as chemical entities, the interest around them has increased through the years. Nowadays, radical chemistry is used in the synthesis of 75% of all polymers, inevitably establishing a close relationship with Solid-Phase Organic Synthesis. More recently, the interest of organic chemists has shifted towards the application of usual “in-solution” radical chemistry to the solid-phase, ranging from the use of supported reagents for radical reactions, to the development of methodologies for the synthesis of small molecules or potential libraries. The aim of this review is to put in perspective radical chemistry, moving it away from its origin as a synthetic means for solid supports, to becoming a useful tool for the synthesis of small molecules. Full article
(This article belongs to the Special Issue Diversity Oriented Synthesis)
Open AccessReview Selenol Protecting Groups in Organic Chemistry: Special Emphasis on Selenocysteine Se-Protection in Solid Phase Peptide Synthesis
Molecules 2011, 16(4), 3232-3251; https://doi.org/10.3390/molecules16043232
Received: 1 March 2011 / Revised: 3 April 2011 / Accepted: 12 April 2011 / Published: 18 April 2011
Cited by 12 | PDF Full-text (308 KB)
Abstract
The appearance of selenium in organic synthesis is relatively rare, and thus examples in the literature pertaining to the masking of its considerable reactivity are similarly uncommon. Greene's Protecting Groups in Organic Synthesis, the standard reference for the state of the art in
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The appearance of selenium in organic synthesis is relatively rare, and thus examples in the literature pertaining to the masking of its considerable reactivity are similarly uncommon. Greene's Protecting Groups in Organic Synthesis, the standard reference for the state of the art in this arena, offers no entries for selenium protective methodology, in stark comparison to its mention of the great variety of protecting groups germane to its chalcogen cousin sulfur. This scarcity of Se-protection methods makes it no less interesting and pertinent toward the construction of selenium-containing organic systems which do indeed require the iterative blocking and de-blocking of selenol functionalities. A selenium-containing system which is especially relevant is selenocysteine, as its use in Solid Phase Peptide Synthesis requires extensive protection of its selenol side chain. This review will attempt to summarize the current state of understanding with regard to selenium protection protocol in organic synthesis. Moreover, it will provide a special emphasis on selenocysteine side chain protection, comprising both the breadth of functionality used for this purpose as well as methods of deprotection. Full article
(This article belongs to the Special Issue Protecting Group in Organic Synthesis)
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