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Molecules, Volume 21, Issue 2 (February 2016) – 117 articles

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628 KiB  
Article
Synthesis of Oxylipin Mimics and Their Antifungal Activity against the Citrus Postharvest Pathogens
by Jimei Ma, Yupeng Li, Hangwei Chen, Zhen Zeng, Zi-Long Li and Hong Jiang
Molecules 2016, 21(2), 254; https://doi.org/10.3390/molecules21020254 - 22 Feb 2016
Cited by 6 | Viewed by 5458
Abstract
Nine oxylipin mimics were designed and synthesized starting from d-mannose. Their antifungal activity against three citrus postharvest pathogens was evaluated by spore germination assay. The results indicated that all the compounds significantly inhibited the growth of Penicillium digitatum, Penicillium italicum and [...] Read more.
Nine oxylipin mimics were designed and synthesized starting from d-mannose. Their antifungal activity against three citrus postharvest pathogens was evaluated by spore germination assay. The results indicated that all the compounds significantly inhibited the growth of Penicillium digitatum, Penicillium italicum and Aspergillus niger. The compound (3Z,6Z,8S,9R,10R)-octadeca-3,6-diene-8,9,10-triol (3) exhibited excellent inhibitory effect on both Penicillium digitatum (IC50 = 34 ppm) and Penicillium italicum (IC50 = 94 ppm). Their in vivo antifungal activities against citrus postharvest blue mold were tested with fruit inoculated with the pathogen Penicillium italicum. The compound (3R,4S)-methyl 3,4-dihydroxy-5-octyltetrahydrofuran-2-carboxylate (9) demonstrated significant efficacy by reducing the disease severity to 60%. The antifungal mechanism of these oxylipin mimics was postulated in which both inhibition of pathogenic mycelium and stimuli of the host oxylipin-mediated defense response played important roles. Full article
(This article belongs to the Section Bioorganic Chemistry)
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3574 KiB  
Article
Phenolics from Garcinia mangostana Inhibit Advanced Glycation Endproducts Formation: Effect on Amadori Products, Cross-Linked Structures and Protein Thiols
by Hossam M. Abdallah, Hany El-Bassossy, Gamal A. Mohamed, Ali M. El-Halawany, Khalid Z. Alshali and Zainy M. Banjar
Molecules 2016, 21(2), 251; https://doi.org/10.3390/molecules21020251 - 22 Feb 2016
Cited by 60 | Viewed by 8123
Abstract
Accumulation of Advanced Glycation Endproducts (AGEs) in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine [...] Read more.
Accumulation of Advanced Glycation Endproducts (AGEs) in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine (AG) as a positive control. Including G. mangostana total methanol extract (GMT) in the reaction mixture of bovine serum albumin (BSA) and glucose or ribose inhibited the fluorescent and non-fluorescent AGEs formation in a dose dependent manner. The bioassay guided fractionation of GMT revealed isolation of four bioactive constituents from the bioactive fraction; which were identified as: garcimangosone D (1), aromadendrin-8-C-glucopyranoside (2), epicatechin (3), and 2,3′,4,5′,6-pentahydroxybenzophenone (4). All the tested compounds significantly inhibited fluorescent and non-fluorescent AGEs formation in a dose dependent manner whereas compound 3 (epicatechin) was found to be the most potent. In search for the level of action, addition of GMT, and compounds 2–4 inhibited fructosamine (Amadori product) and protein aggregation formation in both glucose and ribose. To explore the mechanism of action, it was found that addition of GMT and only compound (3) to reaction mixture increased protein thiol in both glucose and ribose while compounds 1, 2 and 4 only increased thiol in case of ribose. In conclusion, phenolic compounds 1–4 inhibited AGEs formation at the levels of Amadori product and protein aggregation formation through saving protein thiol. Full article
(This article belongs to the Section Natural Products Chemistry)
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1591 KiB  
Article
Multicomponent Synthesis and Evaluation of New 1,2,3-Triazole Derivatives of Dihydropyrimidinones as Acidic Corrosion Inhibitors for Steel
by Rodrigo González-Olvera, Viridiana Román-Rodríguez, Guillermo E. Negrón-Silva, Araceli Espinoza-Vázquez, Francisco Javier Rodríguez-Gómez and Rosa Santillan
Molecules 2016, 21(2), 250; https://doi.org/10.3390/molecules21020250 - 22 Feb 2016
Cited by 42 | Viewed by 8408
Abstract
An efficient one-pot synthesis of 1,2,3-triazole derivatives of dihydropyrimidinones has been developed using two multicomponent reactions. The aldehyde-1,2,3-triazoles were obtained in good yields from in situ-generated organic azides and O-propargylbenzaldehyde. The target heterocycles were synthesized through the Biginelli reaction in which [...] Read more.
An efficient one-pot synthesis of 1,2,3-triazole derivatives of dihydropyrimidinones has been developed using two multicomponent reactions. The aldehyde-1,2,3-triazoles were obtained in good yields from in situ-generated organic azides and O-propargylbenzaldehyde. The target heterocycles were synthesized through the Biginelli reaction in which the aldehyde-1,2,3-triazoles reacted with ethyl acetoacetate and urea in the presence of Ce(OTf)3 as the catalyst. The corrosion inhibition of steel grade API 5 L X52 in 1 M HCl by the synthesized compounds was investigated using the electrochemical impedance spectroscopy technique. The measurements revealed that these heterocycles are promising candidates to inhibit acidic corrosion of steel. Full article
(This article belongs to the Special Issue MCRs and Related One-Pot Organic Synthesis)
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1542 KiB  
Article
Synthesis and Characterization of Some New Coumarins with in Vitro Antitumor and Antioxidant Activity and High Protective Effects against DNA Damage
by Mounir A. I. Salem, Magda I. Marzouk and Azza M. El-Kazak
Molecules 2016, 21(2), 249; https://doi.org/10.3390/molecules21020249 - 22 Feb 2016
Cited by 86 | Viewed by 8640
Abstract
Coumarins are naturally occurring oxygen heterocyclic compounds having multifarious medicinal properties, hence used as lead compounds for designing new potent analogs. The chromene butenoic acid 3 and the benzochromene butenoic acid 4 which are derived from the reaction of glyoxalic acid with 3-acetylcoumarin [...] Read more.
Coumarins are naturally occurring oxygen heterocyclic compounds having multifarious medicinal properties, hence used as lead compounds for designing new potent analogs. The chromene butenoic acid 3 and the benzochromene butenoic acid 4 which are derived from the reaction of glyoxalic acid with 3-acetylcoumarin and 3-acetylbenzocoumarin, respectively, were reacted with different nitrogen and carbon nucleophiles to give new heterocyclic compounds. The structures of the prepared compounds were elucidated by IR, 1H-NMR, and mass spectroscopy. Some of the newly prepared compounds were tested in vitro against a panel of four human tumor cell lines namely; hepatocellular carcinoma (liver) HepG2, colon cancer HCT-116, human prostate cancer PC3, and mammary gland breast MCF-7. Also they were tested as antioxidants. Almost all of the tested compounds showed satisfactory activity. Full article
(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)
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3745 KiB  
Review
Chemistry and Pharmacology of Citrus sinensis
by Juan Manuel J. Favela-Hernández, Omar González-Santiago, Mónica A. Ramírez-Cabrera, Patricia C. Esquivel-Ferriño and María Del Rayo Camacho-Corona
Molecules 2016, 21(2), 247; https://doi.org/10.3390/molecules21020247 - 22 Feb 2016
Cited by 120 | Viewed by 26472
Abstract
Presently the search for new drugs from natural resources is of growing interest to the pharmaceutical industry. Natural products have been the source of new drugs since ancient times. Plants are a good source of secondary metabolites which have been found to have [...] Read more.
Presently the search for new drugs from natural resources is of growing interest to the pharmaceutical industry. Natural products have been the source of new drugs since ancient times. Plants are a good source of secondary metabolites which have been found to have beneficial properties. The present study is a review of the chemistry and pharmacology of Citrus sinensis. This review reveals the therapeutic potential of C. sinensis as a source of natural compounds with important activities that are beneficial for human health that could be used to develop new drugs. Full article
(This article belongs to the Collection Recent Advances in Flavors and Fragrances)
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627 KiB  
Article
Leccinum molle (Bon) Bon and Leccinum vulpinum Watling: The First Study of Their Nutritional and Antioxidant Potential
by Filipa S. Reis, Lillian Barros, Anabela Martins, M. Helena Vasconcelos, Patricia Morales and Isabel C. F. R. Ferreira
Molecules 2016, 21(2), 246; https://doi.org/10.3390/molecules21020246 - 20 Feb 2016
Cited by 6 | Viewed by 5606
Abstract
This work presents the chemical profile of two edible species of mushrooms from the genus Leccinum: Leccinum molle (Bon) Bon and Leccinum vulpinum Watling, both harvested on the outskirts of Bragança (Northeastern Portugal). Both species were prepared and characterized regarding their content in [...] Read more.
This work presents the chemical profile of two edible species of mushrooms from the genus Leccinum: Leccinum molle (Bon) Bon and Leccinum vulpinum Watling, both harvested on the outskirts of Bragança (Northeastern Portugal). Both species were prepared and characterized regarding their content in nutrients (i.e., free sugars, fatty acids and vitamins), non-nutrients (i.e., phenolic and other organic acids) and antioxidant activity. To the best of our knowledge, no previous studies on the chemical characterization and bioactivity of these species have been undertaken. Accordingly, this study intends to increase the available information concerning edible mushroom species, as well as to highlight another important factor regarding the conservation of the mycological resources—their potential as sources of nutraceutical/pharmaceutical compounds. Overall, both species revealed similar nutrient profiles, with low fat levels, fructose, mannitol and trehalose as the foremost free sugars, and high percentages of mono- and polyunsaturated fatty acids. They also revealed the presence of bioactive compounds, namely phenolic (e.g., gallic acid, protocatechuic acid and p-hydroxybenzoic acid) and organic acids (e.g., citric and fumaric acids) and presented antioxidant properties. Full article
(This article belongs to the Section Natural Products Chemistry)
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224 KiB  
Article
Catechin Hydrate Augments the Antibacterial Action of Selected Antibiotics against Staphylococcus aureus Clinical Strains
by Maria Miklasińska, Małgorzata Kępa, Robert D. Wojtyczka, Danuta Idzik, Arkadiusz Dziedzic and Tomasz J. Wąsik
Molecules 2016, 21(2), 244; https://doi.org/10.3390/molecules21020244 - 20 Feb 2016
Cited by 34 | Viewed by 5575
Abstract
Synergistic effects between commonly used antibiotics and natural substances may be an alternative to conventional antibacterial therapies. The objective of the presented study was to assess the in vitro antibacterial activity of catechin hydrate (CH) and evaluate the interactions of CH with selected [...] Read more.
Synergistic effects between commonly used antibiotics and natural substances may be an alternative to conventional antibacterial therapies. The objective of the presented study was to assess the in vitro antibacterial activity of catechin hydrate (CH) and evaluate the interactions of CH with selected antibiotics using Staphylococcus aureus clinical and reference strains. CH displayed diverse activity towards examined S. aureus strains, with minimal inhibitory concentrations (MICs) ranging from 256 to 2048 µg/mL. The interaction between CH and antibiotics was assessed by an E-test. The most significant synergistic effects were noticed for CH in combination with clindamycin and erythromycin. For cefoxitin and vancomycin a decrease of MIC values in the presence of CH was also observed, but it did not reach statistical significance. The obtained results demonstrate that CH shows antimicrobial activity against Staphylococcus aureus clinical strains. What is more, we proved a synergistic effect of CH with erythromycin and clindamycin. Full article
(This article belongs to the Section Medicinal Chemistry)
5674 KiB  
Article
Porphyrin Cobalt(III) “Nitrene Radical” Reactivity; Hydrogen Atom Transfer from Ortho-YH Substituents to the Nitrene Moiety of Cobalt-Bound Aryl Nitrene Intermediates (Y = O, NH)
by Monalisa Goswami, Christophe Rebreyend and Bas De Bruin
Molecules 2016, 21(2), 242; https://doi.org/10.3390/molecules21020242 - 20 Feb 2016
Cited by 21 | Viewed by 10553
Abstract
In the field of cobalt(II) porphyrin-catalyzed metallo-radical reactions, organic azides have emerged as successful nitrene transfer reagents. In the pursuit of employing ortho-YH substituted (Y = O, NH) aryl azides in Co(II) porphyrin-catalyzed nitrene transfer reactions, unexpected hydrogen atom transfer (HAT) from [...] Read more.
In the field of cobalt(II) porphyrin-catalyzed metallo-radical reactions, organic azides have emerged as successful nitrene transfer reagents. In the pursuit of employing ortho-YH substituted (Y = O, NH) aryl azides in Co(II) porphyrin-catalyzed nitrene transfer reactions, unexpected hydrogen atom transfer (HAT) from the OH or NH2 group in the ortho-position to the nitrene moiety of the key radical-intermediate was observed. This leads to formation of reactive ortho-iminoquinonoid (Y = O) and phenylene diimine (Y = NH) species. These intermediates convert to subsequent products in non-catalyzed reactions, as is typical for these free organic compounds. As such, the observed reactions prevent the anticipated cobalt-mediated catalytic radical-type coupling of the nitrene radical intermediates to alkynes or alkenes. Nonetheless, the observed reactions provide valuable insights into the reactivity of transition metal nitrene-radical intermediates, and give access to ortho-iminoquinonoid and phenylene diimine intermediates from ortho-YH substituted aryl azides in a catalytic manner. The latter can be employed as intermediates in one-pot catalytic transformations. From the ortho-hydroxy aryl azide substrates both phenoxizinones and benzoxazines could be synthesized in high yields. From the ortho-amino aryl azide substrates azabenzene compounds were obtained as the main products. Computational studies support these observations, and reveal that HAT from the neighboring OH and NH2 moiety to the nitrene radical moiety has a low energy barrier. Full article
(This article belongs to the Special Issue Organic Azides)
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1242 KiB  
Review
The Impact of Melatonin in Research
by Elena Maria Varoni, Clelia Soru, Roberta Pluchino, Chiara Intra and Marcello Iriti
Molecules 2016, 21(2), 240; https://doi.org/10.3390/molecules21020240 - 20 Feb 2016
Cited by 16 | Viewed by 7823
Abstract
Citation indexes represent helpful tools for evaluating the impact of articles on research. The aim of this study was to obtain the top-100 ranking of the most cited papers on melatonin, a relevant neurohormone mainly involved in phase-adjusting the biological clock and with [...] Read more.
Citation indexes represent helpful tools for evaluating the impact of articles on research. The aim of this study was to obtain the top-100 ranking of the most cited papers on melatonin, a relevant neurohormone mainly involved in phase-adjusting the biological clock and with certain sleep-promoting capability. An article search was carried out on the Institute for Scientific Information (ISI) Web of Science platform. Numbers of citations, names of authors, journals and their 2014-impact factor, year of publication, and experimental designs of studies were recorded. The ranking of the 100-most cited articles on melatonin research (up to February 2016) revealed a citation range from 1623 to 310. Narrative reviews/expert opinions were the most frequently cited articles, while the main research topics were oxidative stress, sleep physiology, reproduction, circadian rhythms and melatonin receptors. This study represents the first detailed analysis of the 100 top-cited articles published in the field of melatonin research, showing its impact and relevance in the biomedical field. Full article
(This article belongs to the Collection Phytochemicals: Biosynthesis, Metabolism and Biological Activities)
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923 KiB  
Article
Discovery of a New Class of Sortase A Transpeptidase Inhibitors to Tackle Gram-Positive Pathogens: 2-(2-Phenylhydrazinylidene)alkanoic Acids and Related Derivatives
by Benedetta Maggio, Demetrio Raffa, Maria Valeria Raimondi, Stella Cascioferro, Fabiana Plescia, Domenico Schillaci, Maria Grazia Cusimano, Ainars Leonchiks, Dmitrijs Zhulenkovs, Livia Basile and Giuseppe Daidone
Molecules 2016, 21(2), 241; https://doi.org/10.3390/molecules21020241 - 19 Feb 2016
Cited by 34 | Viewed by 5792
Abstract
A FRET-based random screening assay was used to generate hit compounds as sortase A inhibitors that allowed us to identify ethyl 3-oxo-2-(2-phenylhydrazinylidene)butanoate as an example of a new class of sortase A inhibitors. Other analogues were generated by changing the ethoxycarbonyl function for [...] Read more.
A FRET-based random screening assay was used to generate hit compounds as sortase A inhibitors that allowed us to identify ethyl 3-oxo-2-(2-phenylhydrazinylidene)butanoate as an example of a new class of sortase A inhibitors. Other analogues were generated by changing the ethoxycarbonyl function for a carboxy, cyano or amide group, or introducing substituents in the phenyl ring of the ester and acid derivatives. The most active derivative found was 3-oxo-2-(2-(3,4dichlorophenyl)hydrazinylidene)butanoic acid (2b), showing an IC50 value of 50 µM. For a preliminary assessment of their antivirulence properties the new derivatives were tested for their antibiofilm activity. The most active compound resulted 2a, which showed inhibition of about 60% against S. aureus ATCC 29213, S. aureus ATCC 25923, S. aureus ATCC 6538 and S. epidermidis RP62A at a screening concentration of 100 µM. Full article
(This article belongs to the Section Medicinal Chemistry)
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3645 KiB  
Article
Synthesis of 2-Alkenyl-2H-indazoles from 2-(2-Carbonylmethyl)-2H-indazoles
by Mei-Huey Lin, Kung-Yu Liang, Chang-Hsien Tsai, Yu-Chun Chen, Hung-Chang Hsiao, Yi-Syuan Li, Chung-Hao Chen and Hau-Chun Wu
Molecules 2016, 21(2), 238; https://doi.org/10.3390/molecules21020238 - 19 Feb 2016
Cited by 2 | Viewed by 5779
Abstract
A procedure has been developed for synthesis of 2-alkenyl-2H-indazoles starting from 2-(2-carbonylmethyl)-2H-indazoles, which are prepared by gallium/aluminium- and aluminium-mediated, direct, regioselective alkylation of indazoles with α-bromocarbonyl compounds. The structure of 3-(2H-indazol-2-yl)-2H-chromen-2-one was proven by X-ray [...] Read more.
A procedure has been developed for synthesis of 2-alkenyl-2H-indazoles starting from 2-(2-carbonylmethyl)-2H-indazoles, which are prepared by gallium/aluminium- and aluminium-mediated, direct, regioselective alkylation of indazoles with α-bromocarbonyl compounds. The structure of 3-(2H-indazol-2-yl)-2H-chromen-2-one was proven by X-ray crystallography. The styrene- and coumarin-2H-indazoles produced by using the new method were found to have interesting fluorescence properties. Full article
(This article belongs to the Section Organic Chemistry)
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Article
Antifungal Activity of Isoliquiritin and Its Inhibitory Effect against Peronophythora litchi Chen through a Membrane Damage Mechanism
by Jianjun Luo, Zhibin Li, Jingjing Wang, Qunfang Weng, Shaohua Chen and Meiying Hu
Molecules 2016, 21(2), 237; https://doi.org/10.3390/molecules21020237 - 19 Feb 2016
Cited by 37 | Viewed by 6870
Abstract
This study investigated the antifungal activity and potential antifungal mechanism(s) of isoliquiritin against P. litchi Chen, one of the main litchi pathogens. The antifungal activity of isoliquiritin against P. litchi Chen had been proven in a dose-dependent manner through in vitro (mycelial growth [...] Read more.
This study investigated the antifungal activity and potential antifungal mechanism(s) of isoliquiritin against P. litchi Chen, one of the main litchi pathogens. The antifungal activity of isoliquiritin against P. litchi Chen had been proven in a dose-dependent manner through in vitro (mycelial growth and sporangia germination) and in vivo (detached leaf) tests. Results revealed that isoliquiritin exhibited significant antifungal activity against the tested pathogens, especially, P. litchi Chen, with a minimum inhibitory concentration of 27.33 mg/L. The morphology of P. litchi Chen was apparently changed by isoliquiritin through cytoplasm leakage and distortion of mycelia. The cell membrane permeability of the P. litchi Chen increased with the increasing concentration of isoliquiritin, as evidenced by a rise in relative electric conductivity and a decrease in reducing sugar contents. These results indicated that the antifungal effects of isoliquiritin could be explained by a membrane lesion mechanism causing damage to the cell membrane integrity leading to the death of mycelial cells. Taken together, isoliquiritin may be used as a natural alternative to commercial fungicides or a lead compound to develop new fungicides for the control of litchi downy blight. Full article
(This article belongs to the Section Natural Products Chemistry)
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2435 KiB  
Review
Molecular Theory of Detonation Initiation: Insight from First Principles Modeling of the Decomposition Mechanisms of Organic Nitro Energetic Materials
by Roman V. Tsyshevsky, Onise Sharia and Maija M. Kuklja
Molecules 2016, 21(2), 236; https://doi.org/10.3390/molecules21020236 - 19 Feb 2016
Cited by 68 | Viewed by 10407
Abstract
This review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation [...] Read more.
This review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation initiation theory in a widely agreed upon form. However, recent advances in experimental and theoretical methods allow for a constructive and rigorous approach to design and test the theory or at least some of its fundamental building blocks. In this review, we analyzed a set of select experimental and theoretical articles, which were augmented by our own first principles modeling and simulations, to reveal new trends in energetic materials and to refine known existing correlations between their structures, properties, and functions. Our consideration is intentionally limited to the processes of thermally stimulated chemical reactions at the earliest stage of decomposition of molecules and materials containing defects. Full article
(This article belongs to the Special Issue 20th Anniversary of Molecules—Recent Advances in Organic Chemistry)
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Article
Characterizing the Solvated Structure of Photoexcited [Os(terpy)2]2+ with X-ray Transient Absorption Spectroscopy and DFT Calculations
by Xiaoyi Zhang, Mátyás Pápai, Klaus B. Møller, Jianxin Zhang and Sophie E. Canton
Molecules 2016, 21(2), 235; https://doi.org/10.3390/molecules21020235 - 19 Feb 2016
Cited by 9 | Viewed by 6440
Abstract
Characterizing the geometric and electronic structures of individual photoexcited dye molecules in solution is an important step towards understanding the interfacial properties of photo-active electrodes. The broad family of “red sensitizers” based on osmium(II) polypyridyl compounds often undergoes small photo-induced structural changes which [...] Read more.
Characterizing the geometric and electronic structures of individual photoexcited dye molecules in solution is an important step towards understanding the interfacial properties of photo-active electrodes. The broad family of “red sensitizers” based on osmium(II) polypyridyl compounds often undergoes small photo-induced structural changes which are challenging to characterize. In this work, X-ray transient absorption spectroscopy with picosecond temporal resolution is employed to determine the geometric and electronic structures of the photoexcited triplet state of [Os(terpy)2]2+ (terpy: 2,2′:6′,2″-terpyridine) solvated in methanol. From the EXAFS analysis, the structural changes can be characterized by a slight overall expansion of the first coordination shell [OsN6]. DFT calculations supports the XTA results. They also provide additional information about the nature of the molecular orbitals that contribute to the optical spectrum (with TD-DFT) and the near-edge region of the X-ray spectra. Full article
(This article belongs to the Special Issue Molecular Engineering for Electrochemical Power Sources)
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Article
Multicomponent Analysis of the Differential Induction of Secondary Metabolite Profiles in Fungal Endophytes
by Víctor González-Menéndez, Mercedes Pérez-Bonilla, Ignacio Pérez-Victoria, Jesús Martín, Francisca Muñoz, Fernando Reyes, José R. Tormo and Olga Genilloud
Molecules 2016, 21(2), 234; https://doi.org/10.3390/molecules21020234 - 18 Feb 2016
Cited by 47 | Viewed by 10029
Abstract
Small molecule histone deacetylase (HDAC) and DNA methyltransferase (DNMT) inhibitors are commonly used to perturb the production of fungal metabolites leading to the induction of the expression of silent biosynthetic pathways. Several reports have described the variable effects observed in natural product profiles [...] Read more.
Small molecule histone deacetylase (HDAC) and DNA methyltransferase (DNMT) inhibitors are commonly used to perturb the production of fungal metabolites leading to the induction of the expression of silent biosynthetic pathways. Several reports have described the variable effects observed in natural product profiles in fungi treated with HDAC and DNMT inhibitors, such as enhanced chemical diversity and/or the induction of new molecules previously unknown to be produced by the strain. Fungal endophytes are known to produce a wide variety of secondary metabolites (SMs) involved in their adaptation and survival within higher plants. The plant-microbe interaction may influence the expression of some biosynthetic pathways, otherwise cryptic in these fungi when grown in vitro. The aim of this study was to setup a systematic approach to evaluate and identify the possible effects of HDAC and DNMT inhibitors on the metabolic profiles of wild type fungal endophytes, including the chemical identification and characterization of the most significant SMs induced by these epigenetic modifiers. Full article
(This article belongs to the Special Issue Applications of Metabolomics within Natural Products Chemistry)
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7542 KiB  
Article
Influence of Thermal Treatment Conditions on the Properties of Dental Silicate Cements
by Georgeta Voicu, Alexandru Mihai Popa, Alina Ioana Badanoiu and Florin Iordache
Molecules 2016, 21(2), 233; https://doi.org/10.3390/molecules21020233 - 18 Feb 2016
Cited by 9 | Viewed by 5627
Abstract
In this study the sol-gel process was used to synthesize a precursor mixture for the preparation of silicate cement, also called mineral trioxide aggregate (MTA) cement. This mixture was thermally treated under two different conditions (1400 °C/2 h and 1450 °C/3 h) followed [...] Read more.
In this study the sol-gel process was used to synthesize a precursor mixture for the preparation of silicate cement, also called mineral trioxide aggregate (MTA) cement. This mixture was thermally treated under two different conditions (1400 °C/2 h and 1450 °C/3 h) followed by rapid cooling in air. The resulted material (clinker) was ground for one hour in a laboratory planetary mill (v = 150 rot/min), in order to obtain the MTA cements. The setting time and mechanical properties, in vitro induction of apatite formation by soaking in simulated body fluid (SBF) and cytocompatibility of the MTA cements were assessed in this study. The hardening processes, nature of the reaction products and the microstructural characteristics were also investigated. The anhydrous and hydrated cements were characterized by different techniques e.g., X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR) and thermal analysis (DTA-DTG-TG). The setting time of the MTA cement obtained by thermal treatment at 1400 °C/2 h (MTA1) was 55 min and 15 min for the MTA cement obtained at 1450 °C/3 h (MTA2). The compressive strength values were 18.5 MPa (MTA1) and 22.9 MPa (MTA2). Both MTA cements showed good bioactivity (assessed by an in vitro test), good cytocompatibility and stimulatory effect on the proliferation of cells. Full article
(This article belongs to the Special Issue Pharmaceutical Nanotechnology: Novel Approaches)
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Article
Bioadhesive Surfactant Systems for Methotrexate Skin Delivery
by Giovana Aparecida de Souza Cintra, Larissa Alvarenga Pinto, Giovana Maria Fioramonti Calixto, Christiane Pienna Soares, Eliete De Souza Von Zuben, Maria Virgínia Scarpa, Maria Palmira Daflon Gremião and Marlus Chorilli
Molecules 2016, 21(2), 231; https://doi.org/10.3390/molecules21020231 - 18 Feb 2016
Cited by 32 | Viewed by 6808
Abstract
Methotrexate (MTX) is an immunosuppressive drug for systemic use in the treatment of skin diseases, however, MTX presents a number of side effects, such as hepatotoxicity. To overcome this limitation, this study developed skin MTX delivery surfactant systems, such as a microemulsion (ME) [...] Read more.
Methotrexate (MTX) is an immunosuppressive drug for systemic use in the treatment of skin diseases, however, MTX presents a number of side effects, such as hepatotoxicity. To overcome this limitation, this study developed skin MTX delivery surfactant systems, such as a microemulsion (ME) and a liquid crystalline system (LCS), consisting of a glycol copolymer-based silicone fluid (SFGC) as oil phase, polyether functional siloxane (PFS) as surfactant, and carbomer homopolymer type A (C971) dispersion at 0.5% (wt/wt) as aqueous phase. Polarized light microscopy and small-angle X-ray scattering evidenced the presence of hexagonal and lamellar LCSs, and also a ME. Texture profile and in vitro bioadhesion assays showed that these formulations are suitable for topical application, showing interesting hardness, adhesiveness and compressibility values. Rheology analysis confirmed the Newtonian behaviour of the ME, whereas lamellar and hexagonal LCSs behave as pseudoplastic and dilatant non-Newtonian fluids, respectively. In vitro release profiles indicated that MTX could be released in a controlled manner from all the systems, and the Weibull model showed the highest adjusted coefficient of determination. Finally, the formulations were not cytotoxic to the immortalized human keratinocyte line HaCaT. Therefore, these bioadhesive surfactant systems established with PFS and C971 have great potential as skin delivery systems. Full article
(This article belongs to the Special Issue Pharmaceutical Nanotechnology: Novel Approaches)
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2422 KiB  
Article
New 3-Cyano-2-Substituted Pyridines Induce Apoptosis in MCF 7 Breast Cancer Cells
by Ahmed Malki, Mona Mohsen, Hassan Aziz, Ola Rizk, Omima Shaban, Mohamed El-Sayed, Zaki A. Sherif and Hayam Ashour
Molecules 2016, 21(2), 230; https://doi.org/10.3390/molecules21020230 - 18 Feb 2016
Cited by 31 | Viewed by 6415
Abstract
The synthesis of new 3-cyano-2-substituted pyridines bearing various pharmacophores and functionalities at position 2 is described. The synthesized compounds were evaluated for their in vitro anti-cancer activities on five cancer cell lines using 5-FU as reference compound. The results revealed that the benzohydrazide [...] Read more.
The synthesis of new 3-cyano-2-substituted pyridines bearing various pharmacophores and functionalities at position 2 is described. The synthesized compounds were evaluated for their in vitro anti-cancer activities on five cancer cell lines using 5-FU as reference compound. The results revealed that the benzohydrazide derivative 9a induced growth inhibition in human breast cancer cell line MCF-7 with an IC50 value of 2 μM and it showed lower cytotoxicity on MCF-12a normal breast epithelial cells. Additionally, 9a induced apoptotic morphological changes and induced apoptosis in MCF-7 in a dose and time-dependent manner according to an enzyme linked immunosorbent apoptosis assay which is further confirmed by a TUNEL assay. Flow cytometric analysis indicated that 9a arrested MCF-7 cells in the G1 phase, which was further confirmed by increased expression of p21 and p27 and reduced expression of CDK2 and CDK4. Western blot data revealed significant upregulation of the expression of p53, Bax, caspase-3 and down-regulation of Bcl-2, Mdm-2 and Akt. Additionally, 9a increased the release of cytochrome c from mitochondria to cytoplasm which provokes the mitochondrial apoptotic pathway while it showed no significant change on the expression of the death receptor proteins procaspase-8, caspase-8 and FAS. Furthermore, 9a reduced the expression of phospho AKT and β-catenin in dose dependent manner while inhibiting the expression of migration-related genes such as matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGF). Our findings suggest that compound 9a could be considered as a lead structure for further development of more potent apoptosis inducing agents with anti-metastatic activities. Full article
(This article belongs to the Section Medicinal Chemistry)
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942 KiB  
Communication
Discovery of Uracil Derivatives as Potent Inhibitors of Fatty Acid Amide Hydrolase
by Yan Qiu, Yang Zhang, Yuhang Li and Jie Ren
Molecules 2016, 21(2), 229; https://doi.org/10.3390/molecules21020229 - 18 Feb 2016
Cited by 6 | Viewed by 5955
Abstract
Fatty Acid Amide Hydrolase (FAAH) is an intracellular serine enzyme involved in the biological degradation of the fatty acid ethanolamide family of signaling lipids, which exerts neuroprotective, anti-inflammatory, and analgesic properties. In the present study, a conjugated 2,4-dioxo-pyrimidine-1-carboxamide scaffold was confirmed as a [...] Read more.
Fatty Acid Amide Hydrolase (FAAH) is an intracellular serine enzyme involved in the biological degradation of the fatty acid ethanolamide family of signaling lipids, which exerts neuroprotective, anti-inflammatory, and analgesic properties. In the present study, a conjugated 2,4-dioxo-pyrimidine-1-carboxamide scaffold was confirmed as a novel template for FAAH inhibitors, based on which, a series of analogues had been prepared for an initial structure-activity relationship (SAR) study. Most of the synthesized compounds displayed moderate to significant FAAH inhibitory potency. Among them, compounds 11 and 14 showed better activity than others, with IC50 values of 21 and 53 nM. SAR analysis indicated that 2,4-dioxopyrimidine-1-carboxamides represented a novel class of potent inhibitors of FAAH, and substitution at the uracil ring or replacement of the N-terminal group might favor the inhibitory potency. Selected compounds of this class may be used as useful parent molecules for further investigation. Full article
(This article belongs to the Section Medicinal Chemistry)
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880 KiB  
Article
Synthesis and Structure-Activity Relationships of Imidazole-Coumarin Conjugates against Hepatitis C Virus
by Shwu-Chen Tsay, Shu-Yu Lin, Wen-Chieh Huang, Ming-Hua Hsu, Kuo Chu Hwang, Chun-Cheng Lin, Jia-Cherng Horng, I-Chia Chen, Jih Ru Hwu, Fa-Kuen Shieh, Pieter Leyssen and Johan Neyts
Molecules 2016, 21(2), 228; https://doi.org/10.3390/molecules21020228 - 18 Feb 2016
Cited by 30 | Viewed by 8571
Abstract
A series of new conjugated compounds with a –SCH2– linkage were synthesized by chemical methods from imidazole and coumarin derivatives. The experimental results indicate that of the twenty newly synthesized imidazole–coumarin conjugates, three of them exhibited appealing EC50 values (5.1–8.4 [...] Read more.
A series of new conjugated compounds with a –SCH2– linkage were synthesized by chemical methods from imidazole and coumarin derivatives. The experimental results indicate that of the twenty newly synthesized imidazole–coumarin conjugates, three of them exhibited appealing EC50 values (5.1–8.4 μM) and selective indices >20 against hepatitis C virus. Their potency and selectivity were increased substantially by modification of their structure with two factors: imidazole nucleus with a hydrogen atom at the N(1) position and coumarin nucleus with a substituent, such as Cl, F, Br, Me, and OMe. These guidelines provide valuable information for further development of conjugated compounds as anti-viral agents. Full article
(This article belongs to the Section Medicinal Chemistry)
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1377 KiB  
Article
Screening and Analysis of the Potential Bioactive Components of Poria cocos (Schw.) Wolf by HPLC and HPLC-MSn with the Aid of Chemometrics
by Ling-Fang Wu, Kun-Feng Wang, Xin Mao, Wen-Yi Liang, Wen-Jing Chen, Shi Li, Qi Qi, Ya-Ping Cui and Lan-Zhen Zhang
Molecules 2016, 21(2), 227; https://doi.org/10.3390/molecules21020227 - 18 Feb 2016
Cited by 40 | Viewed by 6618
Abstract
The aim of the present study was to establish a new method based on Similarity Analysis (SA), Cluster Analysis (CA) and Principal Component Analysis (PCA) to determine the quality of different samples of Poria cocos (Schw.) Wolf obtained from Yunnan, Hubei, Guizhou, Fujian, [...] Read more.
The aim of the present study was to establish a new method based on Similarity Analysis (SA), Cluster Analysis (CA) and Principal Component Analysis (PCA) to determine the quality of different samples of Poria cocos (Schw.) Wolf obtained from Yunnan, Hubei, Guizhou, Fujian, Henan, Guangxi, Anhui and Sichuan in China. For this purpose 15 samples from the different habitats were analyzed by HPLC-PAD and HPLC-MSn. Twenty-three compounds were detected by HPLC-MSn, of which twenty compounds were tentatively identified by comparing their retention times and mass spectrometry data with that of reference compounds and reviewing the literature. The characteristic fragmentations were summarized. 3-epi-Dehydrotumulosic acid (F13), 3-oxo-16α,25-dihydroxylanosta-7,9(11),24(31)-trien-21-oic acid (F4), 3-oxo-6,16α-dihydroxylanosta-7,9(11),24(31)-trien-21-oic acid (F7) and dehydropachymic acid (F15) were deemed to be suitable marker compounds to distinguish between samples of different quality according to CA and PCA. This study provides helpful chemical information for further anti-tumor activity and active mechanism research on P. cocos. The results proved that fingerprint combined with a chemometric approach is a simple, rapid and effective method for the quality discrimination of P. cocos. Full article
(This article belongs to the Section Natural Products Chemistry)
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2160 KiB  
Article
Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from the Osmanthus fragrans Flower
by An-Na Li, Sha Li, Ya Li, Dong-Ping Xu and Hua-Bin Li
Molecules 2016, 21(2), 218; https://doi.org/10.3390/molecules21020218 - 18 Feb 2016
Cited by 20 | Viewed by 5457
Abstract
An ultrasound-assisted extraction (UAE) method was developed to extract natural antioxidants from the Osmanthus fragrans flower. The effect of UAE on antioxidant activity of the extract from the Osmanthus fragrans flower was studied using a Trolox equivalent antioxidant capacity (TEAC) assay. Optimization conditions [...] Read more.
An ultrasound-assisted extraction (UAE) method was developed to extract natural antioxidants from the Osmanthus fragrans flower. The effect of UAE on antioxidant activity of the extract from the Osmanthus fragrans flower was studied using a Trolox equivalent antioxidant capacity (TEAC) assay. Optimization conditions were firstly determined using a single-factor experiment, and response surface methodology was then used to evaluate interaction of several experimental parameters. Analysis of the coefficient of determination showed that second-order polynomial models produced a highly satisfactory fitting of the experimental data with regard to TEAC values (R2 = 0.9829, p < 0.0001). The optimal conditions were 39.1% ethanol, and extraction for 35.2 min at 59.4 °C. Under these conditions, the maximum TEAC value was 584.9 ± 6.0 μmol Trolox/g DW, which was higher than those obtained by the conventional extracting method (486.4 ± 12.6 μmol Trolox/g DW) and the Soxhlet extraction method (339.1 ± 16.2 μmol Trolox/g DW). The crude extract obtained could be used either as a food additive or in pharmaceuticals for the prevention and treatment of diseases caused by oxidative stress. Full article
(This article belongs to the Section Natural Products Chemistry)
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5215 KiB  
Article
Screening of Korean Natural Products for Anti-Adipogenesis Properties and Isolation of Kaempferol-3-O-rutinoside as a Potent Anti-Adipogenetic Compound from Solidago virgaurea
by Young Soo Jang, Zhiqiang Wang, Jeong-Min Lee, Jae-Young Lee and Soon Sung Lim
Molecules 2016, 21(2), 226; https://doi.org/10.3390/molecules21020226 - 17 Feb 2016
Cited by 35 | Viewed by 8767
Abstract
In this study, the anti-adipogenetic activity of 300 plant extracts was investigated using an Oil Red O staining assay in a 3T3-L1 cell line. Our results indicate that three plants, including the stem and leaf of Physalis angulata, the whole grass of [...] Read more.
In this study, the anti-adipogenetic activity of 300 plant extracts was investigated using an Oil Red O staining assay in a 3T3-L1 cell line. Our results indicate that three plants, including the stem and leaf of Physalis angulata, the whole grass of Solidago virgaurea, and the root of Dioscorea nipponica, produced over 90% inhibition of adipogenesis. Kaempferol-3-O-rutinoside, which demonstrated a 48.2% inhibitory effect on adipogenesis without cytotoxicity, was isolated from the butanol layer of a water extract of S. virgaurea guided by the anti-adipogenesis assay in 3T3-L1. PPAR-γ and C/EBPα expression levels were determined using western blot, and our results indicate that kaempferol-3-O-rutinoside has a strong anti-adipogenic effect in 3T3-L1 cells through the suppression of increases in PPAR-γ and C/EBPα expression. Full article
(This article belongs to the Section Natural Products Chemistry)
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7964 KiB  
Article
Antimicrobial Activity and Stability of Short and Long Based Arachnid Synthetic Peptides in the Presence of Commercial Antibiotics
by Ivan Arenas, Elba Villegas, Oliver Walls, Humberto Barrios, Ramon Rodríguez and Gerardo Corzo
Molecules 2016, 21(2), 225; https://doi.org/10.3390/molecules21020225 - 17 Feb 2016
Cited by 32 | Viewed by 6845
Abstract
Four antimicrobial peptides (AMPs) named Pin2[G], Pin2[14], P18K and FA1 were chemically synthesized and purified. The four peptides were evaluated in the presence of eight commercial antibiotics against four microorganisms of medical importance: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and [...] Read more.
Four antimicrobial peptides (AMPs) named Pin2[G], Pin2[14], P18K and FA1 were chemically synthesized and purified. The four peptides were evaluated in the presence of eight commercial antibiotics against four microorganisms of medical importance: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The commercial antibiotics used were amoxicillin, azithromycin, ceftriaxone, gentamicin, levofloxacin, sulfamethoxazole, trimethoprim and vancomycin. The best AMP against P. aeruginosa was the peptide FA1, and the best AMP against S. aureus was Pin2[G]. Both FA1 and Pin2[G] were efficient against E. coli, but they were not effective against K. pneumoniae. As K. pneumoniae was resistant to most of the commercial antibiotics, combinations of the AMPs FA1 and Pin2[G] were prepared with these antibiotics. According to the fractional inhibitory concentration (FIC) index, the best antimicrobial combinations were obtained with concomitant applications of mixtures of FA1 with levofloxacin and sulfamethoxazole. However, combinations of FA1 or Pin2[G] with other antibiotics showed that total inhibitory effect of the combinations were greater than the sum of the individual effects of either the antimicrobial peptide or the antibiotic. We also evaluated the stability of the AMPs. The AMP Pin2[G] manifested the best performance in saline buffer, in supernatants of bacterial growth and in human blood plasma. Nevertheless, all AMPs were cleaved using endoproteolytic enzymes. These data show advantages and disadvantages of AMPs for potential clinical treatments of bacterial infections, using them in conjunction with commercial antibiotics. Full article
(This article belongs to the Collection Antibiotics & Superbugs: New Strategies to Combat Antimicrobial Resistance)
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2349 KiB  
Article
Conjugated Oligo-Aromatic Compounds Bearing a 3,4,5-Trimethoxy Moiety: Investigation of Their Antioxidant Activity Correlated with a DFT Study
by Huda. S. Kareem, Nurdiana Nordin, Thorsten Heidelberg, Azlina Abdul-Aziz and Azhar Ariffin
Molecules 2016, 21(2), 224; https://doi.org/10.3390/molecules21020224 - 17 Feb 2016
Cited by 17 | Viewed by 6932
Abstract
A series of heterocyclic compounds bearing the well-known free radical scavenging 3,4,5-trimethoxybenzyloxy group, was synthesized. The key compound 4-(3,4,5-trimethoxybenzyl-oxy)benzohydrazide was converted into thiosemicarbazide derivatives, which were subsequently cyclized with NaOH to provide 1,2,4-triazole derivatives. Alternative treatment of the acid hydrazide with carbon disulfide [...] Read more.
A series of heterocyclic compounds bearing the well-known free radical scavenging 3,4,5-trimethoxybenzyloxy group, was synthesized. The key compound 4-(3,4,5-trimethoxybenzyl-oxy)benzohydrazide was converted into thiosemicarbazide derivatives, which were subsequently cyclized with NaOH to provide 1,2,4-triazole derivatives. Alternative treatment of the acid hydrazide with carbon disulfide in the presence of KOH led to the corresponding 1,3,4-oxadiazole and various alkylated derivatives. The newly synthesized compounds were purified and the structures of the products were elucidated and confirmed on the basis of their analytical and spectral data. Their antioxidant activities were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and Ferric Reducing Antioxidant Power (FRAP) assays. The thiosemicarbazide derivatives were highly active in both antioxidant assays with the lowest IC50 value for DPPH radical scavenging. Theoretical calculations based on density functional theory (DFT) were performed to understand the relative importance of NH, SH and CH hydrogens on the radical scavenging activities of these compounds. Full article
(This article belongs to the Collection Heterocyclic Compounds)
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1813 KiB  
Article
Novel 2-Phenoxyanilide Congeners Derived from a Hit Structure of the TCAMS: Synthesis and Evaluation of Their in Vitro Activity against Plasmodium falciparum
by Thomas Weidner, Abed Nasereddin, Lutz Preu, Johann Grünefeld, Ron Dzikowski and Conrad Kunick
Molecules 2016, 21(2), 223; https://doi.org/10.3390/molecules21020223 - 17 Feb 2016
Cited by 2 | Viewed by 4986
Abstract
The Tres Cantos Antimalarial Compound Set (TCAMS) is a publicly available compound library which contains 13533 hit structures with confirmed activity against Plasmodium falciparum, the infective agent responsible for malaria tropica. The TCAMS provides a variety of starting points for the investigation [...] Read more.
The Tres Cantos Antimalarial Compound Set (TCAMS) is a publicly available compound library which contains 13533 hit structures with confirmed activity against Plasmodium falciparum, the infective agent responsible for malaria tropica. The TCAMS provides a variety of starting points for the investigation of new antiplasmodial drug leads. One of the promising compounds is TCMDC-137332, which seemed to be a good starting point due to its antiplasmodial potency and its predicted physicochemical properties. Several new analogues based on a 2-phenoxyanilide scaffold were synthesized by standard amide coupling reactions and were fully characterized regarding their identity and purity by spectroscopic and chromatographic methods. Furthermore, the results of the biological evaluation of all congeners against Plasmodium falciparum NF54 strains are presented. The findings of our in vitro screening could not confirm the presumed nanomolar antiplasmodial activity of TCMDC-137332 and its derivatives. Full article
(This article belongs to the Section Medicinal Chemistry)
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6830 KiB  
Article
Antimicrobial Activity of Some Novel Armed Thiophene Derivatives and Petra/Osiris/Molinspiration (POM) Analyses
by Yahia Nasser Mabkhot, Fatima Alatibi, Nahed Nasser E. El-Sayed, Salim Al-Showiman, Nabila Abdelshafy Kheder, Abdul Wadood, Abdur Rauf, Saud Bawazeer and Taibi Ben Hadda
Molecules 2016, 21(2), 222; https://doi.org/10.3390/molecules21020222 - 17 Feb 2016
Cited by 100 | Viewed by 10367
Abstract
Tetrasubstituted 2-acetylthiophene derivative 5 was synthesized and then condensed with various nitrogen nucleophiles such as 5-amino-1,2,4-triazole, 2-aminobenzimidazole, aniline or p-chloroaniline to afford the corresponding iminothiophene derivatives 6–8a,b. Condensation of thiophene 5 with malononitrile as carbon nucleophile afforded compound 9, which underwent nucleophilic [...] Read more.
Tetrasubstituted 2-acetylthiophene derivative 5 was synthesized and then condensed with various nitrogen nucleophiles such as 5-amino-1,2,4-triazole, 2-aminobenzimidazole, aniline or p-chloroaniline to afford the corresponding iminothiophene derivatives 6–8a,b. Condensation of thiophene 5 with malononitrile as carbon nucleophile afforded compound 9, which underwent nucleophilic addition with DMF-DMA to afford compound 10. The newly synthesized products were characterized by elemental analysis, IR, MS, 1H-13C-NMR and CHN analysis and then evaluated for their antimicrobial activity. Results of the in vitro antibacterial activity showed that thiophene derivative 7 was found to be more potent than the standard drug gentamicin against Pseudomonas aeruginosa. Some of these compounds showed potential antimicrobial activities. Molecular docking and Osiris/Molinspiration analyses show the crucial role and impact of substituents on bioactivity and indicate the unfavorable structural parameters in actual drug design: more substitution with electronic donor group doesn’t guarantee more effective bioactivity. This study should greatly help in an intelligent and a controlled pharmacomodulation of antibiotics. Full article
(This article belongs to the Section Bioorganic Chemistry)
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4301 KiB  
Article
DNA Scaffolded Silver Clusters: A Critical Study
by Bidisha Sengupta, Christa Corley, Keith Cobb, Anthony Saracino and Steffen Jockusch
Molecules 2016, 21(2), 216; https://doi.org/10.3390/molecules21020216 - 17 Feb 2016
Cited by 14 | Viewed by 5786
Abstract
Fluorescent silver nanoclusters (Ag-NCs) are in prominence as novel sensing materials due to their biocompatibility, photostability, and molecule-like optical properties. The present work is carried out on an array (17 sequences) of 16 bases long cytosine rich, single stranded DNA templates 5′-C3 [...] Read more.
Fluorescent silver nanoclusters (Ag-NCs) are in prominence as novel sensing materials due to their biocompatibility, photostability, and molecule-like optical properties. The present work is carried out on an array (17 sequences) of 16 bases long cytosine rich, single stranded DNA templates 5′-C3XiC3XiiC3XiiiC3Xiv-3′ where i, ii, iii, iv correspond to T/G/C deoxynucleobases (with default base A). Among all the oligonucleotides, a sequence C3AC3AC3TC3G (3T4G) has been identified, which grows three different near-infrared-emitting NC species with absorption/emission maxima at ~620/700 (species I), 730/800 (species II), and 830 (Species III) nm, respectively. The nature of the spectral profiles, along with relevant parameters namely absorption maximum (\(\lambda_{abs}^{max}\)), emission maximum (\(\lambda_{em}^{max}\)), anisotropy (r), lifetime (\(\tau\)), circular dichroism spectral data are used to understand the microenvironments of the fluorescent NC species I, II, and III. DNA:Ag stiochiometric, pH and solvent dependent studies proved that i-motif scaffolds with different folding topologies are associated with the growth of these three species and a certain concentration of silver and H+ favor the growth of species III. Size exclusion chromatographic measurements provided similar indications that a folded, more compact, classic i-motif template is associated with the formation of the longer NIR (~830 nm) absorbing species. This study provides a more definitive approach to design and obtain a targeted DNA templated Ag-NC with required emission properties for biophysical and cellular applications. Full article
(This article belongs to the Special Issue Frontiers in Nucleic Acid Chemistry)
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981 KiB  
Review
Molecular Mechanisms of Inhibition of Streptococcus Species by Phytochemicals
by Soheila Abachi, Song Lee and H. P. Vasantha Rupasinghe
Molecules 2016, 21(2), 215; https://doi.org/10.3390/molecules21020215 - 17 Feb 2016
Cited by 56 | Viewed by 13861
Abstract
This review paper summarizes the antibacterial effects of phytochemicals of various medicinal plants against pathogenic and cariogenic streptococcal species. The information suggests that these phytochemicals have potential as alternatives to the classical antibiotics currently used for the treatment of streptococcal infections. The phytochemicals [...] Read more.
This review paper summarizes the antibacterial effects of phytochemicals of various medicinal plants against pathogenic and cariogenic streptococcal species. The information suggests that these phytochemicals have potential as alternatives to the classical antibiotics currently used for the treatment of streptococcal infections. The phytochemicals demonstrate direct bactericidal or bacteriostatic effects, such as: (i) prevention of bacterial adherence to mucosal surfaces of the pharynx, skin, and teeth surface; (ii) inhibition of glycolytic enzymes and pH drop; (iii) reduction of biofilm and plaque formation; and (iv) cell surface hydrophobicity. Collectively, findings from numerous studies suggest that phytochemicals could be used as drugs for elimination of infections with minimal side effects. Full article
(This article belongs to the Special Issue 20th Anniversary of Molecules—Recent Advances in Natural Products)
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2211 KiB  
Review
Focus on Chirality of HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors
by Valeria Famiglini and Romano Silvestri
Molecules 2016, 21(2), 221; https://doi.org/10.3390/molecules21020221 - 16 Feb 2016
Cited by 22 | Viewed by 8141
Abstract
Chiral HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) are of great interest since one enantiomer is often more potent than the corresponding counterpart against the HIV-1 wild type (WT) and the HIV-1 drug resistant mutant strains. This review exemplifies the various studies made to [...] Read more.
Chiral HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) are of great interest since one enantiomer is often more potent than the corresponding counterpart against the HIV-1 wild type (WT) and the HIV-1 drug resistant mutant strains. This review exemplifies the various studies made to investigate the effect of chirality on the antiretroviral activity of top HIV-1 NNRTI compounds, such as nevirapine (NVP), efavirenz (EFV), alkynyl- and alkenylquinazolinone DuPont compounds (DPC), diarylpyrimidine (DAPY), dihydroalkyloxybenzyloxopyrimidine (DABO), phenethylthiazolylthiourea (PETT), indolylarylsulfone (IAS), arylphosphoindole (API) and trifluoromethylated indole (TFMI) The chiral separation, the enantiosynthesis, along with the biological properties of these HIV-1 NNRTIs, are discussed. Full article
(This article belongs to the Special Issue Chiral Drugs)
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