Molecules

14 pages, 341 KiB

Open AccessArticle

Evaluation of Silica-H₂SO₄ as an Efficient Heterogeneous Catalyst for the Synthesis of Chalcones

by Aeysha Sultan, Abdul Rauf Raza, Muhammad Abbas, Khalid Mohammed Khan, Muhammad Nawaz Tahir and Nazamid Saari

Molecules 2013, 18(8), 10081-10094; https://doi.org/10.3390/molecules180810081 - 20 Aug 2013

Cited by 28 | Viewed by 8198

Abstract

We report an efficient silica-H₂SO₄ mediated synthesis of a variety of chalcones that afforded the targeted compounds in very good yield compared to base catalyzed solvent free conditions as well as acid or base catalyzed refluxing conditions. Full article

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25 pages, 1475 KiB

Open AccessArticle

Modeling the Interaction of Dodecylphosphocholine Micelles with the Anticoccidial Peptide PW2 Guided by NMR Data

by Francisco Gomes-Neto, Ana Paula Valente and Fabio C. L. Almeida

Molecules 2013, 18(8), 10056-10080; https://doi.org/10.3390/molecules180810056 - 20 Aug 2013

Cited by 9 | Viewed by 6906

Abstract

Antimicrobial peptides are highly dynamic entities that acquire structure upon binding to a membrane interface. To better understand the structure and the mechanism for the molecular recognition of dodecylphosphocholine (DPC) micelles by the anticoccidial peptide PW2, we performed molecular dynamics (MD) simulations guided [...] Read more.

Antimicrobial peptides are highly dynamic entities that acquire structure upon binding to a membrane interface. To better understand the structure and the mechanism for the molecular recognition of dodecylphosphocholine (DPC) micelles by the anticoccidial peptide PW2, we performed molecular dynamics (MD) simulations guided by NMR experimental data, focusing on strategies to explore the transient nature of micelles, which rearrange on a millisecond to second timescale. We simulated the association of PW2 with a pre-built DPC micelle and with free-DPC molecules that spontaneously forms micelles in the presence of the peptide along the simulation. The simulation with spontaneous micelle formation provided the adequate environment which replicated the experimental data. The unrestrained MD simulations reproduced the NMR structure for the entire 100 ns MD simulation time. Hidden discrete conformational states could be described. Coulomb interactions are important for initial approximation and hydrogen bonds for anchoring the aromatic region at the interface, being essential for the stabilization of the interaction. Arg9 is strongly attached with phosphate. We observed a helix elongation process stabilized by the intermolecular peptide-micelle association. Full association that mimics the experimental data only happens after complete micelle re-association. Fast micelle dynamics without dissociation of surfactants leads to only superficial binding. Full article

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14 pages, 317 KiB

Open AccessCommunication

Total Synthesis, Cytotoxic Effects of Damnacanthal, Nordamnacanthal and Related Anthraquinone Analogues

by Muhammad Nadeem Akhtar, Seema Zareen, Swee Keong Yeap, Wan Yong Ho, Kong Mun Lo, Aurangzeb Hasan and Noorjahan Banu Alitheen

Molecules 2013, 18(8), 10042-10055; https://doi.org/10.3390/molecules180810042 - 20 Aug 2013

Cited by 27 | Viewed by 11864

Abstract

Naturally occurring anthraquinones, damnacanthal (1) and nordamnacanthal (2) were synthesized with modified reaction steps and investigated for their cytotoxicity against the MCF-7 and K-562 cancer cell lines, respectively. Intermediate analogues 2-bromomethyl-1,3-dimethoxyanthraquinone (5, IC₅₀ = 5.70 ± [...] Read more.

Naturally occurring anthraquinones, damnacanthal (1) and nordamnacanthal (2) were synthesized with modified reaction steps and investigated for their cytotoxicity against the MCF-7 and K-562 cancer cell lines, respectively. Intermediate analogues 2-bromomethyl-1,3-dimethoxyanthraquinone (5, IC₅₀ = 5.70 ± 0.21 and 8.50 ± 1.18 mg/mL), 2-hydroxymethyl-1,3-dimethoxyanthraquinone (6, IC₅₀ = 12.10 ± 0.14 and 14.00 ± 2.13), 2-formyl-1,3-dimethoxyantharquinone (7, IC₅₀ = 13.10 ± 1.02 and 14.80 ± 0.74), 1,3-dimethoxy-2-methylanthraquinone (4, IC₅₀ = 9.40 ± 3.51 and 28.40 ± 2.33), and 1,3-dihydroxy-2-methylanthraquinone (3, IC₅₀ = 25.60 ± 0.42 and 28.40 ± 0.79) also exhibited moderate cytotoxicity against MCF-7 and K-562 cancer cell lines, respectively. Other structurally related compounds like 1,3-dihydroxyanthraquinone (13a, IC₅₀ = 19.70 ± 0.35 and 14.50 ± 1.28), 1,3-dimethoxyanthraquinone (13b, IC₅₀ = 6.50 ± 0.66 and 5.90 ± 0.95) were also showed good cytotoxicity. The target compound damnacanthal (1) was found to be the most cytotoxic against the MCF-7 and K-562 cancer cell lines, with IC₅₀ values of 3.80 ± 0.57 and 5.50 ± 1.26, respectively. The structures of all compounds were elucidated with the help of detailed spectroscopic techniques. Full article

(This article belongs to the Section Organic Chemistry)

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18 pages, 289 KiB

Open AccessArticle

Volatile Aroma Compounds in Various Brewed Green Teas

by Jeehyun Lee, Delores H. Chambers, Edgar Chambers IV, Koushik Adhikari and Youngmo Yoon

Molecules 2013, 18(8), 10024-10041; https://doi.org/10.3390/molecules180810024 - 20 Aug 2013

Cited by 77 | Viewed by 11830

Abstract

This study identifies and semi-quantifies aroma volatiles in brewed green tea samples. The objectives of this study were to identify using a gas chromatograph-mass spectrometer (GC-MS) paired with a headspace solid-phase micro-extraction (HS-SPME) the common volatile compounds that may be responsible for aroma/flavor [...] Read more.

This study identifies and semi-quantifies aroma volatiles in brewed green tea samples. The objectives of this study were to identify using a gas chromatograph-mass spectrometer (GC-MS) paired with a headspace solid-phase micro-extraction (HS-SPME) the common volatile compounds that may be responsible for aroma/flavor of the brewed liquor of a range of green tea samples from various countries as consumed and to determine if green teas from the same region have similarities in volatile composition when green tea samples are prepared for consumption. Twenty-four green tea samples from eight different countries were brewed as recommended for consumer brewing. The aroma volatiles were extracted by HS-SPME, separated on a gas chromatograph and identified using a mass spectrometer. Thirty-eight compounds were identified and the concentrations were semi-quantified. The concentrations were lower than those reported by other researchers, probably because this research examined headspace volatiles from brewed tea rather than solvent extraction of leaves. No relationship to country of origin was found, which indicates that other factors have a greater influence than country of origin on aroma. Full article

(This article belongs to the Special Issue Flavors and Fragrances)

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10 pages, 258 KiB

Open AccessArticle

Antianxiety-Like Effects of Chimpi (Dried Citrus Peels) in the Elevated Open-Platform Test

by Aya Ito, Noriyuki Shin, Takashi Tsuchida, Toshiki Okubo and Hisayoshi Norimoto

Molecules 2013, 18(8), 10014-10023; https://doi.org/10.3390/molecules180810014 - 20 Aug 2013

Cited by 34 | Viewed by 8358

Abstract

Dried citrus peels (Chimpi) is one of the most common natural medicines with qi (energy flow) rectifying and shi (dampness) drying actions, which originates from Citrus unshiu, and/or C. reticulata according to the definition of the pharmacopoeiae of Japan and China. [...] Read more.

Dried citrus peels (Chimpi) is one of the most common natural medicines with qi (energy flow) rectifying and shi (dampness) drying actions, which originates from Citrus unshiu, and/or C. reticulata according to the definition of the pharmacopoeiae of Japan and China. In this study, the pharmacological effects of their extracts and major chemical constituents hesperidin and its aglycone hesperetin on anxiety were examined with an anxiety model of elevated open-platform test using ICR male mice (6-week-old) and total duration of freezing was decreased in fluoxetine-treated mice, which is a simple and highly sensitive to the effects of serotonergic anxiolytics. Moreover, yokukansankachimpihange (YKH), a combination of yokukansan with Chimpi and Hange (Pinellia) was also examined because Chimpi is considered to play a crucial part in this formula against anxious symptoms in dementia patients. The results showed that Chimpi and YKH possess a significant anxiolytic-like effect similar to that of fluoxetine, suggesting that they might be similar to fluoxetine in their pharmacological actions through the serotonergic neurotransmission pathway. Moreover, it also suggested that the major chemical constituent, hesperidin could be an active principle attributed to the antianxiety-like effects with a direct and indirect role via its aglycone hesperetin. Full article

(This article belongs to the Section Natural Products Chemistry)

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15 pages, 4706 KiB

Open AccessArticle

Combination of Small Molecule Microarray and Confocal Microscopy Techniques for Live Cell Staining Fluorescent Dye Discovery

by Eszter Molnár, Soujanya Kuntam, Pradeep Kumar Reddy Cingaram, Begüm Peksel, Bhavyashree Suresh, Gabriella Fábián, Liliána Z. Fehér, Attila Bokros, Ágnes Medgyesi, Ferhan Ayaydin and László G. Puskás

Molecules 2013, 18(8), 9999-10013; https://doi.org/10.3390/molecules18089999 - 20 Aug 2013

Cited by 10 | Viewed by 9090

Abstract

Discovering new fluorochromes is significantly advanced by high-throughput screening (HTS) methods. In the present study a combination of small molecule microarray (SMM) prescreening and confocal laser scanning microscopy (CLSM) was developed in order to discover novel cell staining fluorescent dyes. Compounds with high [...] Read more.

Discovering new fluorochromes is significantly advanced by high-throughput screening (HTS) methods. In the present study a combination of small molecule microarray (SMM) prescreening and confocal laser scanning microscopy (CLSM) was developed in order to discover novel cell staining fluorescent dyes. Compounds with high native fluorescence were selected from a 14,585-member library and further tested on living cells under the microscope. Eleven compartment-specific, cell-permeable (or plasma membrane-targeted) fluorochromes were identified. Their cytotoxicity was tested and found that between 1–10 micromolar range, they were non-toxic even during long-term incubations. Full article

(This article belongs to the Special Issue Reagents and Methods for Protein Target Identification)

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17 pages, 623 KiB

Open AccessArticle

Enantio- and Periselective Nitroalkene Diels-Alder Reactions Catalyzed by Helical-Chiral Hydrogen Bond Donor Catalysts

by Zhili Peng, Maurice J. Narcis and Norito Takenaka

Molecules 2013, 18(8), 9982-9998; https://doi.org/10.3390/molecules18089982 - 19 Aug 2013

Cited by 6 | Viewed by 7068

Abstract

Helical-chiral double hydrogen bond donor catalysts promote the nitroalkene Diels-Alder reaction in an enantio- and periselective manner. This represents the first asymmetric catalytic nitroalkene Diels-Alder reaction via LUMO-lowering catalysis. To gain an insight into this new process, the substrate scope of our catalyst [...] Read more.

Helical-chiral double hydrogen bond donor catalysts promote the nitroalkene Diels-Alder reaction in an enantio- and periselective manner. This represents the first asymmetric catalytic nitroalkene Diels-Alder reaction via LUMO-lowering catalysis. To gain an insight into this new process, the substrate scope of our catalyst was investigated by exploiting readily available 5-substituted pentamethylcyclopentadienes. The catalyst was found to tolerate dienes with different steric demands as well as dienes substituted with heteroatoms. The synthetic utility of 5-substituted pentamethylcyclopentadienes is rather limited, and thus we have developed a three-step route to 1,4,5,5-tetrasubstituted cyclopentadienes from commercially available ketones. Full article

(This article belongs to the Special Issue Asymmetric Catalysis)

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16 pages, 592 KiB

Open AccessArticle

Anti-Lung Cancer Activity through Enhancement of Immunomodulation and Induction of Cell Apoptosis of Total Triterpenes Extracted from Ganoderma luncidum (Leyss. ex Fr.) Karst.

by Liang Feng, Ling Yuan, Meng Du, Yan Chen, Ming-Hua Zhang, Jun-Fei Gu, Jun-Jie He, Ying Wang and Wei Cao

Molecules 2013, 18(8), 9966-9981; https://doi.org/10.3390/molecules18089966 - 19 Aug 2013

Cited by 39 | Viewed by 7622

Abstract

Ganoderma luncidum (Leyss. ex Fr.) Karst. (GLK) has been used traditionally for the prevention and treatment of cancers or tumors for a long time in Traditional Chinese Medicine. The triterpenes as main effective components of GLK have been found to be beneficial for [...] Read more.

Ganoderma luncidum (Leyss. ex Fr.) Karst. (GLK) has been used traditionally for the prevention and treatment of cancers or tumors for a long time in Traditional Chinese Medicine. The triterpenes as main effective components of GLK have been found to be beneficial for the efficacy. The purpose of this study was to examine the anti-lung cancer activity of triterpenes of GLK in vitro and in vivo and to explore their anti-lung cancer effects and potential mechanisms. A549 cells and Lewis tumor-bearing mice were used to evaluate the inhibition effects of triterpenes on cell proliferation and tumor growth. The IC₅₀ of triterpenes of GLK on A549 cells was 24.63 μg/mL. Triterpenes of GLK could significantly inhibit tumor growth in mice (30, 60 and 120 mg/kg). The immune organs indexes including spleen and thymus were increased remarkedly by the treatment with triterpenes. Moreover, they were able to stimulate the immune response by increasing the expressions of IL-6 and TNF-α. Flow cytometric analysis revealed that cell arrest caused by triterpenes treatment (7.5, 15 and 30 μg/mL) was in the G2/M phase in A549 cells. Triterpenes induced apoptosis by decreasing the expression of the antiapoptotic protein Bcl-2 and pro-caspase 9 and increasing the levels of cleaved-caspase 9. Our findings suggested that the triterpenes of GLK have anti-lung cancer activity in vitro and in vivo via enhancement of immunomodulation and induction of cell apoptosis. The study provides insights into the mechanism of GLK in the prevention and treatment of lung cancer. Full article

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17 pages, 607 KiB

Open AccessArticle

Neuroprotective, Anti-Amyloidogenic and Neurotrophic Effects of Apigenin in an Alzheimer’s Disease Mouse Model

by Le Zhao, Jun-Li Wang, Rui Liu, Xiao-Xu Li, Jian-Fei Li and Lu Zhang

Molecules 2013, 18(8), 9949-9965; https://doi.org/10.3390/molecules18089949 - 19 Aug 2013

Cited by 248 | Viewed by 13035

Abstract

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by extracellular senile plaques and intracellular neurofibrillary tangles in the brain. Amyloid-β peptides (Aβ) are considered to play a critical role in the onset and progression of AD. Apigenin (4',5,7-trihydroxyflavone) is a pharmacologically active agent. [...] Read more.

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by extracellular senile plaques and intracellular neurofibrillary tangles in the brain. Amyloid-β peptides (Aβ) are considered to play a critical role in the onset and progression of AD. Apigenin (4',5,7-trihydroxyflavone) is a pharmacologically active agent. Even though some evidence suggests that it has potential neuroprotective effects, no preexisting study has reported any therapeutic effects of apigenin in AD models. In the present study, we examined the effects of apigenin on cognitive function in APP/PS1 double transgenic AD mice and explored its mechanism(s) of action. Three-month oral treatment with apigenin rescued learning deficits and relieved memory retention in APP/PS1 mice. Apigenin also showed effects affecting APP processing and preventing Aβ burden due to the down-regulation of BACE1 and β-CTF levels, the relief of Aβ deposition, and the decrease of insoluble Aβ levels. Moreover, apigenin exhibited superoxide anion scavenging effects and improved antioxidative enzyme activity of superoxide dismutase and glutathione peroxidase. In addition, apigenin restored neurotrophic ERK/CREB/BDNF pathway in the cerebral cortex. In conclusion, apigenin may ameliorate AD-associated learning and memory impairment through relieving Aβ burden, suppressing amyloidogenic process, inhibiting oxidative stress, and restoring ERK/CREB/BDNF pathway. Therefore, apigenin appears to represent an alternative medication for the prevention and/or therapy of AD. Full article

(This article belongs to the Section Natural Products Chemistry)

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16 pages, 284 KiB

Open AccessArticle

Characterization and Bioactivity of Polysaccharides Obtained from Pine Cones of Pinus koraiensis by Graded Ethanol Precipitation

by Pan Zou, Xin Yang, Wei-Wei Huang, Hai-Tian Zhao, Jing Wang, Ren-Bo Xu, Xing-Long Hu, Si-Yan Shen and Di Qin

Molecules 2013, 18(8), 9933-9948; https://doi.org/10.3390/molecules18089933 - 19 Aug 2013

Cited by 59 | Viewed by 7977

Abstract

Pinus koraiensis polysaccharides (PKP) were extracted by hot water from P. koraiensis pine cones. Five polysaccharide fractions named PKP-A, PKP-B, PKP-C, PKP-D and PKP-E were successfully separated at final ethanol concentrations of 30%, 50%, 60%, 70% and 80%, respectively. HPLC, FT-IR, GC-MS and [...] Read more.

Pinus koraiensis polysaccharides (PKP) were extracted by hot water from P. koraiensis pine cones. Five polysaccharide fractions named PKP-A, PKP-B, PKP-C, PKP-D and PKP-E were successfully separated at final ethanol concentrations of 30%, 50%, 60%, 70% and 80%, respectively. HPLC, FT-IR, GC-MS and automatic amino-acid analysis were applied to investigate their chemical characteristics. Monosaccharide component analysis indicated that the five fractions were all composed of d-ribose, l-rhamnose, l-arabinose, d-xylose, d-mannose, d-glucose and d-galactose, but their molar ratios were quite different. HPLC results revealed that the polysaccharides precipitated by higher concentrations of ethanol solution had lower molecular masses. Moreover, the antioxidant activities of the five fractions were studied on the basis of hydroxyl radical and ABTS radical scavenging tests. The five graded polysaccharide fractions exhibited good inhibitory power, and MTT tests in vitro showed the IC₅₀ of PKP-A and PKP-E were 1,072.5 and 2,070.0 μg·mL⁻¹, respectively. These results demonstrated that the PKP could be a potential source of natural antioxidants or dietary supplements. Full article

(This article belongs to the Section Natural Products Chemistry)

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14 pages, 907 KiB

Open AccessArticle

Chemistry and Antiviral Activity of Arrabidaea pulchra (Bignoniaceae)

by Geraldo Célio Brandão, Erna G. Kroon, Danielle E.R. Souza, José D. Souza Filho and Alaíde Braga Oliveira

Molecules 2013, 18(8), 9919-9932; https://doi.org/10.3390/molecules18089919 - 16 Aug 2013

Cited by 37 | Viewed by 7264

Abstract

The aim of the present work was to carry out a bioguided isolation of antiviral chemical constituents from an ethanol extract of leaves from Arrabidaea pulchra (Cham.) Sandwith (EEAPL) that had shown in vitro activity in a previous screening using DNA and RNA [...] Read more.

The aim of the present work was to carry out a bioguided isolation of antiviral chemical constituents from an ethanol extract of leaves from Arrabidaea pulchra (Cham.) Sandwith (EEAPL) that had shown in vitro activity in a previous screening using DNA and RNA viruses. The activity of EEPAL was evaluated against the DNA viruses Human herpesvirus 1 (HSV-1) and Vaccinia virus Western Reserve (VACV-WR) as well as against the RNA viruses Murine encephalomyocarditis virus (EMCV), and Dengue virus 2 (DENV-2) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. Cytotoxicity was determined in LLCMK₂ and Vero cells and the Selectivity Indexes (SI) were calculated. The most potent effect was observed against DENV-2 (EC₅₀ 46.8 ± 1.6 µg mL⁻¹; SI 2.7). For HSV-1 and VACV-WR EC₅₀ values > 200 µg mL⁻¹ were determined, while no inhibition of the cytopathic effect was observed with EMCV. Bioguided fractionation of EEAPL by partition between immiscible solvents followed by chromatography over a Sephadex LH20 column afforded two arylpropanoid glycosides, verbascoside (AP 1) and caffeoylcalleryanin (AP 2), along with a terpenoid, ursolic acid (AP 3). AP 1 and AP 3 exhibited similar anti-DENV-2 profiles, with SI values of 3.8 and 3.1, respectively, while AP 2 was the most effective anti-DENV-2 constituent, with a SI of 20.0. Our results show that A. pulchra leaves ethanol extract (EEAPL) affords compounds with antiviral activity, mainly against DENV-2. Full article

(This article belongs to the Section Natural Products Chemistry)

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18 pages, 1926 KiB

Open AccessArticle

Kinetics of Nitric Oxide and Oxygen Gases on Porous Y-Stabilized ZrO₂-Based Sensors

by Sajin Killa, Ling Cui, Erica P. Murray and Daniela S. Mainardi

Molecules 2013, 18(8), 9901-9918; https://doi.org/10.3390/molecules18089901 - 16 Aug 2013

Cited by 13 | Viewed by 6049

Abstract

Using impedance spectroscopy the electrical response of sensors with various porous Y-stabilized ZrO₂ (YSZ) microstructures was measured for gas concentrations containing 0–100 ppm NO with 10.5%O₂ at temperatures ranging from 600–700 °C. The impedance response increased substantially as the sensor porosity [...] Read more.

Using impedance spectroscopy the electrical response of sensors with various porous Y-stabilized ZrO₂ (YSZ) microstructures was measured for gas concentrations containing 0–100 ppm NO with 10.5%O₂ at temperatures ranging from 600–700 °C. The impedance response increased substantially as the sensor porosity increased from 46%–50%. Activation energies calculated based on data from the impedance measurements increased in magnitude (97.4–104.9 kJ/mol for 100 ppm NO) with respect to increasing YSZ porosity. Analysis of the oxygen partial pressure dependence of the sensors suggested that dissociative adsorption was the dominant rate limiting. The PWC/DNP theory level was used to investigate the gas-phase energy barrier of the 2NO+O₂→2NO₂ reaction on a 56-atom YSZ/Au model cluster using Density Functional Theory and Linear Synchronous Transit/Quadratic Synchronous Transit calculations. The reaction path shows oxygen surface reactions that begin with NO association with adsorbed O₂ on a Zr surface site, followed by O₂ dissociative adsorption, atomic oxygen diffusion, and further NO₂ formation. The free energy barrier was calculated to be 181.7 kJ/mol at PWC/DNP. A qualitative comparison with the extrapolated data at 62% ± 2% porosity representing the YSZ model cluster indicates that the calculated barriers are in reasonable agreement with experiments, especially when the RPBE functional is used. Full article

(This article belongs to the Special Issue Gas Phase Reactions)

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51 pages, 2445 KiB

Open AccessReview

Breathing Some New Life into an Old Topic: Chalcogen-Nitrogen π-Heterocycles as Electron Acceptors

by Anton V. Lonchakov, Oleg A. Rakitin, Nina P. Gritsan and Andrey V. Zibarev

Molecules 2013, 18(8), 9850-9900; https://doi.org/10.3390/molecules18089850 - 16 Aug 2013

Cited by 91 | Viewed by 9331

Abstract

Recent progress in the design, synthesis and characterization of chalcogen-nitrogen π-heterocycles, mostly 1,2,5-chalcogenadiazoles (chalcogen: S, Se and Te) and their fused derivatives, possessing positive electron affinity is discussed together with their use in preparation of charge-transfer complexes and radical-anion salts—candidate building blocks of [...] Read more.

Recent progress in the design, synthesis and characterization of chalcogen-nitrogen π-heterocycles, mostly 1,2,5-chalcogenadiazoles (chalcogen: S, Se and Te) and their fused derivatives, possessing positive electron affinity is discussed together with their use in preparation of charge-transfer complexes and radical-anion salts—candidate building blocks of molecule-based electrical and magnetic functional materials. Full article

(This article belongs to the Special Issue Chalcogen-Nitrogen Chemistry)

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17 pages, 1150 KiB

Open AccessArticle

ADIBO-Based “Click” Chemistry for Diagnostic Peptide Micro-Array Fabrication: Physicochemical and Assay Characteristics

by Denis Prim, Fabien Rebeaud, Vincent Cosandey, Roger Marti, Philippe Passeraub and Marc E. Pfeifer

Molecules 2013, 18(8), 9833-9849; https://doi.org/10.3390/molecules18089833 - 16 Aug 2013

Cited by 16 | Viewed by 10291

Abstract

Several azide-derivatized and fluorescently-labeled peptides were immobilized on azadibenzocyclooctyne (ADIBO)-activated slide surfaces via a strain-promoted alkyne-azide cycloaddition (SPAAC) reaction revealing excellent immobilization kinetics, good spot homogeneities and reproducible fluorescence signal intensities. A myc-peptide micro-array immunoassay showed an antibody limit-of-detection (LOD) superior to [...] Read more.

Several azide-derivatized and fluorescently-labeled peptides were immobilized on azadibenzocyclooctyne (ADIBO)-activated slide surfaces via a strain-promoted alkyne-azide cycloaddition (SPAAC) reaction revealing excellent immobilization kinetics, good spot homogeneities and reproducible fluorescence signal intensities. A myc-peptide micro-array immunoassay showed an antibody limit-of-detection (LOD) superior to a microtiter plate-based ELISA. Bovine serum albumin (BSA) and dextran covalently attached via “click” chemistry more efficiently reduced non-specific binding (NSB) of fluorescently-labeled IgG to the microarray surface in comparison to immobilized hexanoic acid and various types of polyethylene glycol (PEG) derivatives. Confirmation of these findings via further studies with other proteins and serum components could open up new possibilities for human sample and microarray platform-based molecular diagnostic tests. Full article

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15 pages, 320 KiB

Open AccessArticle

Eco-Friendly Synthesis and Antiproliferative Evaluation of Some Oxygen Substituted Diaryl Ketones

by Paola Arenas, Andrés Peña, David Ríos, Julio Benites, Giulio G. Muccioli, Pedro Buc Calderon and Jaime A. Valderrama

Molecules 2013, 18(8), 9818-9832; https://doi.org/10.3390/molecules18089818 - 16 Aug 2013

Cited by 23 | Viewed by 7161

Abstract

A broad variety of oxygen-substituted diaryl ketones has been synthesized by solar energy-induced Friedel Crafts acylations of 1,4-benzo- and 1,4-naphthoquinones with benzaldehydes. The in vitro antiproliferative properties of the photoproducts were assessed on prostate (DU-145), bladder (T24) and breast (MCF7) human-derived tumor cell [...] Read more.

A broad variety of oxygen-substituted diaryl ketones has been synthesized by solar energy-induced Friedel Crafts acylations of 1,4-benzo- and 1,4-naphthoquinones with benzaldehydes. The in vitro antiproliferative properties of the photoproducts were assessed on prostate (DU-145), bladder (T24) and breast (MCF7) human-derived tumor cell lines and compared to non-tumor mouse fibroblasts (Balb/3T3). Among the tested compounds, it was found that those containing a 3,4,5-trimethoxyphenyl A-ring, such as 12 and 22 are more active on DU-145, with EC₅₀ values of 1.2 and 5.9 μM, respectively. By comparing their effects on the three cancer cell lines, the analogue 22 has the best mean selective index (2.4). Full article

(This article belongs to the Section Organic Chemistry)

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21 pages, 702 KiB

Open AccessReview

Click Chemistry in Peptide-Based Drug Design

by Huiyuan Li, Rachna Aneja and Irwin Chaiken

Molecules 2013, 18(8), 9797-9817; https://doi.org/10.3390/molecules18089797 - 16 Aug 2013

Cited by 175 | Viewed by 20222

Abstract

Click chemistry is an efficient and chemoselective synthetic method for coupling molecular fragments under mild reaction conditions. Since the advent in 2001 of methods to improve stereochemical conservation, the click chemistry approach has been broadly used to construct diverse chemotypes in both chemical [...] Read more.

Click chemistry is an efficient and chemoselective synthetic method for coupling molecular fragments under mild reaction conditions. Since the advent in 2001 of methods to improve stereochemical conservation, the click chemistry approach has been broadly used to construct diverse chemotypes in both chemical and biological fields. In this review, we discuss the application of click chemistry in peptide-based drug design. We highlight how triazoles formed by click reactions have been used for mimicking peptide and disulfide bonds, building secondary structural components of peptides, linking functional groups together, and bioconjugation. The progress made in this field opens the way for synthetic approaches to convert peptides with promising functional leads into structure-minimized and more stable forms. Full article

(This article belongs to the Collection Advances in Click Chemistry)

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12 pages, 223 KiB

Open AccessArticle

Chemical Composition and Biological Activities of Essential Oils of Eremanthus erythropappus (DC) McLeisch (Asteraceae)

by Marcelo S. Silvério, Glauciemar Del-Vechio-Vieira, Míriam A. O. Pinto, Maria S. Alves and Orlando V. Sousa

Molecules 2013, 18(8), 9785-9796; https://doi.org/10.3390/molecules18089785 - 16 Aug 2013

Cited by 42 | Viewed by 7210

Abstract

The chemical composition of the essential oils obtained by hydrodistillation of different parts of Eremanthus erythropappus, including leaves, branches and inflorescences, was investigated by Gas Chromatography and Gas Chromatography/Mass Spectrometry. The antimicrobial activity of the oils was assessed by the disc diffusion [...] Read more.

The chemical composition of the essential oils obtained by hydrodistillation of different parts of Eremanthus erythropappus, including leaves, branches and inflorescences, was investigated by Gas Chromatography and Gas Chromatography/Mass Spectrometry. The antimicrobial activity of the oils was assessed by the disc diffusion and microdilution methods, while the antioxidant activity was evaluated by DPPH and reducing power tests. The main compounds found in the essential oils derived from the inflorescences and leaves were β-caryophyllene, germacrene-D, α-copaene and β-pinene. α-Bisabolol was the major component in the branches. The oils were active against Staphylococcus aureus, Streptococcus pyogenes and fungi, but not Escherichia coli and Pseudomonas aeruginosa. The MIC values ranged from 0.01 to 0.50 mg/mL. Using the DPPH test, the IC₅₀ values ranged from 38.77 ± 0.76 to 102.24 ± 1.96 μg/mL, while the reducing power test produced IC₅₀ values between 109.85 ± 1.68 and 169.53 ± 0.64 μg/mL. The results revealed that the E. erythropappus oils are new promising potential sources of antimicrobial and antioxidant compounds with good future practical applications for human health. Full article

(This article belongs to the Section Natural Products Chemistry)

15 pages, 1758 KiB

Open AccessArticle

Antidiabetic and Antioxidant Properties of Alkaloids from Catharanthus roseus (L.) G. Don

by Soon Huat Tiong, Chung Yeng Looi, Hazrina Hazni, Aditya Arya, Mohammadjavad Paydar, Won Fen Wong, Shiau-Chuen Cheah, Mohd Rais Mustafa and Khalijah Awang

Molecules 2013, 18(8), 9770-9784; https://doi.org/10.3390/molecules18089770 - 15 Aug 2013

Cited by 216 | Viewed by 19508

Abstract

Catharanthus roseus (L.) G. Don is a herbal plant traditionally used by local populations in India, South Africa, China and Malaysia to treat diabetes. The present study reports the in vitro antioxidant and antidiabetic activities of the major alkaloids isolated from Catharanthus roseus [...] Read more.

Catharanthus roseus (L.) G. Don is a herbal plant traditionally used by local populations in India, South Africa, China and Malaysia to treat diabetes. The present study reports the in vitro antioxidant and antidiabetic activities of the major alkaloids isolated from Catharanthus roseus (L.) G. Don leaves extract. Four alkaloids—vindoline I, vindolidine II, vindolicine III and vindolinine IV—were isolated and identified from the dichloromethane extract (DE) of this plant’s leaves. DE and compounds I–III were not cytotoxic towards pancreatic β-TC6 cells at the highest dosage tested (25.0 µg/mL). All four alkaloids induced relatively high glucose uptake in pancreatic β-TC6 or myoblast C2C12 cells, with III showing the highest activity. In addition, compounds II–IV demonstrated good protein tyrosine phosphatase-1B (PTP-1B) inhibition activity, implying their therapeutic potential against type 2 diabetes. III showed the highest antioxidant potential in ORAC and DPPH assays and it also alleviated H₂O₂-induced oxidative damage in β-TC6 cells at 12.5 µg/mL and 25.0 µg/mL. Full article

(This article belongs to the Section Natural Products Chemistry)

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15 pages, 265 KiB

Open AccessArticle

Characterization of Nucleosides and Nucleobases in Natural Cordyceps by HILIC–ESI/TOF/MS and HILIC–ESI/MS

by Heng-Qiang Zhao, Xiao Wang, Hong-Mei Li, Bin Yang, Hong-Jun Yang and Luqi Huang

Molecules 2013, 18(8), 9755-9769; https://doi.org/10.3390/molecules18089755 - 15 Aug 2013

Cited by 45 | Viewed by 8281

Abstract

A method combining hydrophilic interaction chromatography (HILIC) and electrospray ionization mass spectrometry (ESI-MS) was developed for the characterization and determination of natural Cordyceps. Separation was achieved on a Waters Xbridge Amide column with gradient elution. Identification of 15 target nucleosides and nucleobases [...] Read more.

A method combining hydrophilic interaction chromatography (HILIC) and electrospray ionization mass spectrometry (ESI-MS) was developed for the characterization and determination of natural Cordyceps. Separation was achieved on a Waters Xbridge Amide column with gradient elution. Identification of 15 target nucleosides and nucleobases was based on retention time, UV spectra and mass measurements of the protonated molecules ([M+H]⁺) and main fragment ions (ESI-TOF/MS). Eight non-target compounds were tentatively identified by ESI-TOF/MS. The 15 target compounds were quantified by HILIC-ESI-MS/MS using time-programmed selective ion monitoring or multiple reaction monitoring in positive-ion mode under optimized mass conditions. This technique showed good linearity, repeatability and recovery. This approach was also successfully implemented in the analysis of nucleosides and nucleobases in 12 batches of natural Cordyceps samples that were collected from different regions in China. The developed HILIC-ESI-MS method exhibited clear advantages in identifying and determining highly polar bioactive components in Cordyceps, as well as their quality control. Full article

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20 pages, 840 KiB

Open AccessArticle

NMR Study on the Interaction of Trehalose with Lactose and Its Effect on the Hydrogen Bond Interaction in Lactose

by Eric Morssing Vilén and Corine Sandström

Molecules 2013, 18(8), 9735-9754; https://doi.org/10.3390/molecules18089735 - 14 Aug 2013

Cited by 12 | Viewed by 9079

Abstract

Trehalose, a well-known stress-protector of biomolecules, has been investigated for its effect on the mobility, hydration and hydrogen bond interaction of lactose using diffusion-ordered NMR spectroscopy and NMR of hydroxy protons. In ternary mixtures of trehalose, lactose and water, the two sugars have [...] Read more.

Trehalose, a well-known stress-protector of biomolecules, has been investigated for its effect on the mobility, hydration and hydrogen bond interaction of lactose using diffusion-ordered NMR spectroscopy and NMR of hydroxy protons. In ternary mixtures of trehalose, lactose and water, the two sugars have the same rate of diffusion. The chemical shifts, temperature coefficients, vicinal coupling constants and ROE of the hydroxy protons in trehalose, lactose and sucrose were measured for the disaccharides alone in water/acetone-d₆ solutions as well as in mixtures. The data indicated that addition of trehalose did not change significantly the strength of the hydrogen bond interaction between GlcOH3 and GalO5' in lactose. Small upfield shifts were however measured for all hydroxy protons when the sugar concentration was increased. The chemical shift of the GlcOH3 signal in lactose showed less change, attributed to the spatial proximity to GalO5'. Chemical exchange between hydroxy protons of lactose and trehalose was observed in the ROESY NMR spectra. Similar effects were observed with sucrose indicating no specific effect of trehalose at the concentrations investigated (73 to 763 mg/mL) and suggesting that it is the concentration of hydroxy groups more than the type of sugars which is guiding intermolecular interactions. Full article

(This article belongs to the Special Issue NMR of Proteins and Small Biomolecules)

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8 pages, 446 KiB

Open AccessArticle

Uncarilic Acid and Secouncarilic Acid, Two New Triterpenoids from Uucaria sessilifructus

by Mao-Juan Zhang, Bing Liu, Shang-Gao Liao, You-Kai Xu, De-Qiang Feng, Kai-Long Ji and Yan Li

Molecules 2013, 18(8), 9727-9734; https://doi.org/10.3390/molecules18089727 - 14 Aug 2013

Cited by 6 | Viewed by 6141

Abstract

Two new compounds, the 6-oxo oleanane-type triterpenoid uncarilic acid, and its 5,6-secotriterpenoid derivative, secouncarilic acid, were isolated from the hooks and stems of Uucaria sessilifructus together with seven known ursane-type triterpenoids. Uncarilic acid is the second 6-oxo oleanane-type triterpenoid ever reported, while secouncarilic [...] Read more.

Two new compounds, the 6-oxo oleanane-type triterpenoid uncarilic acid, and its 5,6-secotriterpenoid derivative, secouncarilic acid, were isolated from the hooks and stems of Uucaria sessilifructus together with seven known ursane-type triterpenoids. Uncarilic acid is the second 6-oxo oleanane-type triterpenoid ever reported, while secouncarilic acid is the first oleanane-type 5,6-secotriterpenoid. A plausible biosynthetic pathway from uncarilic acid to secouncarilic acid was also postulated. The inhibitory activities of all the nine compounds against LPS-induced nitric oxide production in RAW264.7 macrophages were evaluated. Full article

(This article belongs to the Section Natural Products Chemistry)

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10 pages, 790 KiB

Open AccessArticle

Highly Efficient Biotransformation of Polydatin to Resveratrol by Snailase Hydrolysis Using Response Surface Methodology Optimization

by Zi Wang, Li-Chun Zhao, Wei Li, Lian-Xue Zhang, Jing Zhang and Jian Liang

Molecules 2013, 18(8), 9717-9726; https://doi.org/10.3390/molecules18089717 - 13 Aug 2013

Cited by 22 | Viewed by 7708

Abstract

Resveratrol (RV), a dietary antioxidant polyphenolic compound found in grapes and red wine, exerts a wide variety of pharmacological activities. However, lower content in plants compared with polydatin (PD, the glucoside of RV) limits its application in the food and pharmaceutical industries. In [...] Read more.

Resveratrol (RV), a dietary antioxidant polyphenolic compound found in grapes and red wine, exerts a wide variety of pharmacological activities. However, lower content in plants compared with polydatin (PD, the glucoside of RV) limits its application in the food and pharmaceutical industries. In this paper, we carried out efficient biotransformation of PD to RV with 100% conversion yield by snailase hydrolysis. Moreover, response surface methodology (RSM) was used to optimize the effects of the reaction temperature, enzyme load, and reaction time on the conversion process. Validation of the RSM model was verified by the good agreement between the experimental and the predicted RV yield values. The optimum preparation conditions were as follows: temperature of 62.0 °C, enzyme load of 6.6%, and reaction time of 96 min. The proposed method may be highly applicable for the enzymatic preparation of RV for medicinal purposes. Full article

(This article belongs to the Section Natural Products Chemistry)

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13 pages, 1154 KiB

Open AccessArticle

Enzymatic Synthesis of Extremely Pure Triacylglycerols Enriched in Conjugated Linoleic Acids

by Yu Cao, Weifei Wang, Yang Xu, Bo Yang and Yonghua Wang

Molecules 2013, 18(8), 9704-9716; https://doi.org/10.3390/molecules18089704 - 13 Aug 2013

Cited by 15 | Viewed by 5741

Abstract

This work was objectively targeted to synthesize extremely pure triacylglycerols (TAG) enriched in conjugated linoleic acids (CLAs) for medical and dietetic purposes. Extremely pure CLA-enriched TAG was successfully synthesized by using the multi-step process: TAG was primarily synthesized by lipase-catalyzed esterification of CLA [...] Read more.

This work was objectively targeted to synthesize extremely pure triacylglycerols (TAG) enriched in conjugated linoleic acids (CLAs) for medical and dietetic purposes. Extremely pure CLA-enriched TAG was successfully synthesized by using the multi-step process: TAG was primarily synthesized by lipase-catalyzed esterification of CLA and glycerol and then the lower glycerides [monoacylglycerol (MAG) and diacylglycerol (DAG)] in the esterification mixtures was hydrolyzed to free fatty acids (FFAs) by a mono- and di-acylglycerol lipase (lipase SMG1), finally, the FFAs were further separated from TAG by low temperature (150 °C) molecular distillation. The operation parameters for the lipase SMG1-catalyzed hydrolysis were optimized using response surface methodology based on the central composite rotatable design (CCRD). The operation parameters included water content, pH and reaction temperature and all of these three parameters showed significant effects on the hydrolysis of lower glycerides. The optimal conditions were obtained with a water content of 66.4% (w/w, with respect to oil mass), pH at 5.7 and 1 h of reaction time at 19.6 °C. Under these conditions, the content of lower glycerides in the reaction mixture decreased from 45.2% to 0.3% and the purity of CLA-enriched TAG reached 99.7%. Further purification of TAG was accomplished by molecular distillation and the final CLA-enriched TAG product yielded 99.8% of TAG. These extremely pure CLA-enriched TAG would be used for in vivo studies in animals and humans in order to get speciﬁc information concerning CLA metabolism. Full article

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20 pages, 440 KiB

Open AccessArticle

The Synthesis and the Biological Evaluation of New Thiazolidin-4-one Derivatives Containing a Xanthine Moiety

by Florentina Geanina Lupascu, Oana Maria Dragostin, Liliana Foia, Dan Lupascu and Lenuta Profire

Molecules 2013, 18(8), 9684-9703; https://doi.org/10.3390/molecules18089684 - 13 Aug 2013

Cited by 22 | Viewed by 6442

Abstract

Starting from theophylline (1,3-dimethylxanthine) new thiazolidin-4-one derivatives 7a_1–7, 7b_1–7 have been synthesized as potential antidiabetic drugs. The structure of the new derivatives was confirmed using spectral methods (FT-IR, ¹H-NMR, ¹³C-NMR). The in vitro antioxidant potential of the synthesized [...] Read more.

Starting from theophylline (1,3-dimethylxanthine) new thiazolidin-4-one derivatives 7a_1–7, 7b_1–7 have been synthesized as potential antidiabetic drugs. The structure of the new derivatives was confirmed using spectral methods (FT-IR, ¹H-NMR, ¹³C-NMR). The in vitro antioxidant potential of the synthesized compounds was evaluated according to the ferric reducing power, the total antioxidant activity and the DPPH and ABTS radical scavenging assays. Reactive oxygen species (ROS) and free radicals are considered to be implicated in a variety of pathological events, such as diabetes mellitus and its micro- and macrovascular complications. The results of chemical modulation of the thiazolidin-4-one intermediaries 6a, 6b through condensation with several aromatic aldehydes is the improvement of the antioxidant effect. All benzylidenethiazolidin-4-one derivatives 7a_1–7, 7b_1–7 are more active than their parent thiazolidin-4-ones. The most active compounds are the ones obtained by reaction of condensation with 4-hydroxybenzaldehyde (compounds 7a₅, 7a₆), 4-dimethylaminobenzaldehyde (compounds 7a₆, 7b₆) and 2-nitrobenzaldehyde (compounds 7a₇, 7b₇). Full article

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14 pages, 410 KiB

Open AccessReview

The Emerging Role of Ferumoxytol-Enhanced MRI in the Management of Cerebrovascular Lesions

by Nohra Chalouhi, Pascal Jabbour, Vincent Magnotta and David Hasan

Molecules 2013, 18(8), 9670-9683; https://doi.org/10.3390/molecules18089670 - 13 Aug 2013

Cited by 25 | Viewed by 6727

Abstract

Inflammation is increasingly being understood to be a key component to the pathophysiology of cerebrovascular lesions. Ferumoxytol, an iron oxide nanoparticle coated by a carbohydrate shell, has been used in MRI studies as an inflammatory marker because it is cleared by macrophages. Ferumoxytol-enhanced [...] Read more.

Inflammation is increasingly being understood to be a key component to the pathophysiology of cerebrovascular lesions. Ferumoxytol, an iron oxide nanoparticle coated by a carbohydrate shell, has been used in MRI studies as an inflammatory marker because it is cleared by macrophages. Ferumoxytol-enhanced MRI has emerged as an important tool for noninvasive assessment of the inflammatory status of cerebrovascular lesions, namely aneurysms and arteriovenous malformations. Moreover, preliminary evidence suggests that ferumoxytol-enhanced MRI could be applied as a non-invasive tool to differentiate “unstable” lesions that require early intervention from “stable” lesions in which observation may be safe. Assessment of the effects of anti-inflammatory pharmacological interventions on cerebrovascular lesions is also a potentially crucial application of the technique. Future improvements in technique and MRI signal quantification will certainly pave the way for widespread and efficient use of ferumoxytol-enhanced MRI in clinical practice. In this paper, we review current data regarding ferumoxytol-enhanced MRI and discuss its current/potential applications and future perspectives. Full article

(This article belongs to the Special Issue Contrast Agents)

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7 pages, 205 KiB

Open AccessArticle

Three Novel Xanthones from Garcinia paucinervis and Their Anti-TMV Activity

by Yu-Ping Wu, Wei Zhao, Zhen-Yuan Xia, Guang-Hui Kong, Xiu-Ping Lu, Qiu-Fen Hu and Xue-Mei Gao

Molecules 2013, 18(8), 9663-9669; https://doi.org/10.3390/molecules18089663 - 13 Aug 2013

Cited by 29 | Viewed by 6061

Abstract

Phytochemical investigations of the leaves of Garcinia paucinervis resulted in the isolation of three new xanthones 1–3 and five known analogues 4–8. Structural elucidations of 1–3 were performed by spectral methods such as 1D and 2D [...] Read more.

Phytochemical investigations of the leaves of Garcinia paucinervis resulted in the isolation of three new xanthones 1–3 and five known analogues 4–8. Structural elucidations of 1–3 were performed by spectral methods such as 1D and 2D (HMQC, HMBC, and ROESY) NMR spectroscopy, in addition to high resolution mass spectrometry. Compounds 1–3 showed anti-TMV activities, with inhibition rates above 20%, especially for 1, which had a lower IC₅₀ value of 21.4 µM. Full article

(This article belongs to the Section Natural Products Chemistry)

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13 pages, 612 KiB

Open AccessReview

Ring Expansion of Vinylaziridines through the Strain-Release Pericyclic Reaction: Recent Developments and Applications

by Yu Mi Heo and Seung-Mann Paek

Molecules 2013, 18(8), 9650-9662; https://doi.org/10.3390/molecules18089650 - 12 Aug 2013

Cited by 20 | Viewed by 7442

Abstract

Recent syntheses of azetidines, pyrrolidines, piperidines and azepines through cycloaddition or sigmatropic rearrangements of vinylaziridines are described. Applications to natural product synthesis and mechanistic investigations are also summarized. Full article

(This article belongs to the Special Issue Bioorthogonal Chemistry)

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9 pages, 309 KiB

Open AccessArticle

Phenylpropanoid, Sapnol A, Lignan and Neolignan Sophorosides, Saposides A and B, Isolated from Canadian Sugar Maple Sap

by Kazuko Yoshikawa, Sakiko Tani, Chihiro Baba and Toshihiro Hashimoto

Molecules 2013, 18(8), 9641-9649; https://doi.org/10.3390/molecules18089641 - 12 Aug 2013

Cited by 10 | Viewed by 6747

Abstract

One new phenolic compound, sapnol A (1), and two new aromatic sophorosides, named saposides A (2) and B (3) were isolated from sugar maple sap. In addition, seven known phenolic compounds 4–10 were isolated. These [...] Read more.

One new phenolic compound, sapnol A (1), and two new aromatic sophorosides, named saposides A (2) and B (3) were isolated from sugar maple sap. In addition, seven known phenolic compounds 4–10 were isolated. These structures were determined on the basis of NMR experiments as well as chemical evidence. Furthermore, all the isolated compounds 1–10 were tested for antioxidative activity by the superoxide dismutase (SOD)-like assay. Full article

(This article belongs to the Section Natural Products Chemistry)

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18 pages, 503 KiB

Open AccessArticle

Susceptibility of Staphylococcus aureus Clinical Isolates to Propolis Extract Alone or in Combination with Antimicrobial Drugs

by Robert D. Wojtyczka, Arkadiusz Dziedzic, Danuta Idzik, Małgorzata Kępa, Robert Kubina, Agata Kabała-Dzik, Joanna Smoleń-Dzirba, Jerzy Stojko, Mieczysław Sajewicz and Tomasz J. Wąsik

Molecules 2013, 18(8), 9623-9640; https://doi.org/10.3390/molecules18089623 - 12 Aug 2013

Cited by 81 | Viewed by 10645

Abstract

The objective of this study was to assess in vitro the antimicrobial activity of ethanolic extract of Polish propolis (EEPP) against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates. The combined effect of EEPP and 10 selected antistaphylococcal drugs on [...] Read more.

The objective of this study was to assess in vitro the antimicrobial activity of ethanolic extract of Polish propolis (EEPP) against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates. The combined effect of EEPP and 10 selected antistaphylococcal drugs on S. aureus clinical cultures was also investigated. EEPP composition was analyzed by a High Performance Liquid Chromatography (HPLC) method. The flavonoid compounds identified in Polish Propolis included flavones, flavonones, flavonolols, flavonols and phenolic acids. EEPP displayed varying effectiveness against twelve S. aureus strains, with minimal inhibitory concentration (MIC) within the range from 0.39 to 0.78 mg/mL, determined by broth microdilution method. The average MIC was 0.54 ± 0.22 mg/mL, while calculated MIC₅₀ and MIC₉₀ were 0.39 mg/mL and 0.78 mg/mL, respectively. The minimum bactericidal concentration (MBC) of the EEPP ranged from 0.78 to 3.13 mg/mL. The in vitro combined effect of EEPP and 10 antibacterial drugs was investigated using disk diffusion method-based assay. Addition of EEPP to cefoxitin (FOX), clindamycin (DA), tetracycline (TE), tobramycin (TOB), linezolid (LIN), trimethoprim+sulfamethoxazole (SXT), penicillin (P), erythromycin (E) regimen, yielded stronger, cumulative antimicrobial effect, against all tested S. aureus strains than EEPP and chemotherapeutics alone. In the case of ciprofloxacin (CIP) and chloramphenicol (C) no synergism with EEPP was observed. Full article

(This article belongs to the Section Natural Products Chemistry)

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20 pages, 867 KiB

Open AccessArticle

Synthesis of Photoresponsive Dual NIR Two-Photon Absorptive [60]Fullerene Triads and Tetrads

by Seaho Jeon, Min Wang, Loon-Seng Tan, Thomas Cooper, Michael R. Hamblin and Long Y. Chiang

Molecules 2013, 18(8), 9603-9622; https://doi.org/10.3390/molecules18089603 - 12 Aug 2013

Cited by 4 | Viewed by 6678

Abstract

Broadband nonlinear optical (NLO) organic nanostructures exhibiting both ultrafast photoresponse and a large cross-section of two-photon absorption throughout a wide NIR spectrum may make them suitable for use as nonlinear biophotonic materials. We report here the synthesis and characterization of two C₆₀ [...] Read more.

Broadband nonlinear optical (NLO) organic nanostructures exhibiting both ultrafast photoresponse and a large cross-section of two-photon absorption throughout a wide NIR spectrum may make them suitable for use as nonlinear biophotonic materials. We report here the synthesis and characterization of two C₆₀-(antenna)_x analogous compounds as branched triad C₆₀(>DPAF-C₁₈)(>CPAF-C_2M) and tetrad C₆₀(>DPAF-C₁₈)(>CPAF-C_2M)₂ nanostructures. These compounds showed approximately equal extinction coefficients of optical absorption over 400–550 nm that corresponds to near-IR two-photon based excitation wavelengths at 780–1,100 nm. Accordingly, they may be utilized as potential precursor candidates to the active-core structures of photosensitizing nanodrugs for 2γ-PDT in the biological optical window of 800–1,050 nm. Full article

(This article belongs to the Section Organic Chemistry)

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Molecules, Volume 18, Issue 8 (August 2013) – 86 articles , Pages 8712-10094

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