Synthesis of naturally-derived macromolecules through simplified electrochemically mediated ATRP

The flavonoid-based macroinitiator was received for the first time by the transesterification reaction of quercetin with 2-bromoisobutyryl bromide. In accordance with the “grafting from” strategy, a naturally-occurring star-like polymer with a polar 3,3',4',5,6-pentahydroxyflavone core and hydrophobic poly(tert-butyl acrylate) (PtBA) side arms was synthesized via a simplified electrochemically mediated ATRP (seATRP), utilizing only 78 ppm by weight (wt) of a catalytic CuII complex. To demonstrate the possibility of temporal control, seATRP was carried out utilizing a multiple-step potential electrolysis. The rate of the polymerizations was well-controlled by applying optimal potential values during preparative electrolysis to prevent the possibility of intermolecular coupling of the growing polymer arms. This appears to be the first report using on-demand seATRP for the synthesis of QC-(PtBA-Br)5 pseudo-star polymers. The naturally-derived macromolecules showed narrow MWDs (Đ = 1.08–1.11). 1H NMR spectral results confirm the formation of quercetin-based polymers. These new flavonoid-based polymer materials may find applications as antifouling coatings and drug delivery systems.

Download Full-text

Metabolites Produced by the Phytopathogenic Fungus Rhizoctonia solani: Isolation, Chemical Structure Determination, Syntheses and Bioactivity

Zeitschrift für Naturforschung C ◽

10.1515/znc-2005-9-1010 ◽

2005 ◽

Vol 60 (9-10) ◽

pp. 717-722 ◽

Cited By ~ 15

Author(s):

M. Soledade C. Pedras ◽

Yang Yu ◽

Jun Liu ◽

Yudelsy A. Tandron-Moya

Keyword(s):

Biological Activity ◽

Rhizoctonia Solani ◽

Structure Determination ◽

Chemical Structure ◽

Phytopathogenic Fungus ◽

H Nmr ◽

Naturally Occurring ◽

Chiral Solvating Agent ◽

First Time ◽

Absolute Stereochemistry

Abstract The isolation, structure determination, syntheses and biological activity of Nb-acetyltryptamine and three proline containing dioxopiperazines, cyclo(S-Pro-S-Leu) (2), cyclo(S-Pro- S-Ile) (3), and cyclo(S-Pro-S-Val) (4), from cultures of Rhizoctonia solani Kuhn are reported here for the first time. Despite the small amounts isolated, the absolute stereochemistry of these naturally occurring dioxopiperazines was established by 1H NMR using for the first time the chiral solvating agent (R)-(D)-2,2,2-trifluoro-1-(9-anthryl)ethanol.

Download Full-text

Flavonoid Glycosides with a Triazole Moiety for Marine Antifouling Applications: Synthesis and Biological Activity Evaluation

Marine Drugs ◽

10.3390/md19010005 ◽

2020 ◽

Vol 19 (1) ◽

pp. 5

Author(s):

Daniela Pereira ◽

Catarina Gonçalves ◽

Beatriz T. Martins ◽

Andreia Palmeira ◽

Vitor Vasconcelos ◽

...

Keyword(s):

Qsar Model ◽

Quantitative Structure Activity Relationship ◽

Artemia Salina ◽

Flavonoid Glycosides ◽

Antifouling Activity ◽

Antifouling Coatings ◽

Marine Industry ◽

Low Toxicity ◽

Polymethoxylated Flavones ◽

First Time

Over the last decades, antifouling coatings containing biocidal compounds as active ingredients were used to prevent biofouling, and eco-friendly alternatives are needed. Previous research from our group showed that polymethoxylated chalcones and glycosylated flavones obtained by synthesis displayed antifouling activity with low toxicity. In this work, ten new polymethoxylated flavones and chalcones were synthesized for the first time, including eight with a triazole moiety. Eight known flavones and chalcones were also synthesized and tested in order to construct a quantitative structure-activity relationship (QSAR) model for these compounds. Three different antifouling profiles were found: three compounds (1b, 11a and 11b) exhibited anti-settlement activity against a macrofouling species (Mytilus galloprovincialis), two compounds (6a and 6b) exhibited inhibitory activity against the biofilm-forming marine bacteria Roseobacter litoralis and one compound (7b) exhibited activity against both mussel larvae and microalgae Navicula sp. Hydrogen bonding acceptor ability of the molecule was the most significant descriptor contributing positively to the mussel larvae anti-settlement activity and, in fact, the triazolyl glycosylated chalcone 7b was the most potent compound against this species. The most promising compounds were not toxic to Artemia salina, highlighting the importance of pursuing the development of new synthetic antifouling agents as an ecofriendly and sustainable alternative for the marine industry.

Download Full-text

Synthesis and characterization of meso-to-meso directly linked porphyrin-diazaporphyrin triads

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424618500633 ◽

2018 ◽

Vol 22 (09n10) ◽

pp. 814-820

Author(s):

Yingying Jia ◽

Ling Xu ◽

Bangshao Yin ◽

Mingbo Zhou ◽

Jianxin Song

Keyword(s):

Nickel Complex ◽

High Resolution Mass Spectrometry ◽

Dihedral Angles ◽

X Ray Diffraction ◽

Extinction Coefficients ◽

X Ray ◽

H Nmr ◽

First Time ◽

Molar Extinction Coefficients

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.

Download Full-text

Microbialite-like structures in Cladophora sp. (Ulvophyceae) mats from a subtropical Andean basin: ecological implications

Revista de Biología Tropical ◽

10.15517/rbt.v67i1.31542 ◽

2019 ◽

Vol 67 (1) ◽

Author(s):

Hugo R. Fernández ◽

Ana Lucia Gonzalez Achem ◽

Marcela Correa ◽

Virginia H. Albarracín

Keyword(s):

Organic Pollution ◽

Biological Factors ◽

X Ray Diffraction ◽

Calcite Precipitation ◽

Annual Cycles ◽

X Ray ◽

Naturally Occurring ◽

Ecological Implications ◽

First Time ◽

Solubility Equilibrium

The solubility equilibrium of calcite is influenced by physicochemical, climatic and biological factors. Annual cycles of exceptionally prolonged drought, in conjunction with naturally occurring diffuse organic pollution, generate the unique conditions for the precipitation of lithified carbonate structures (microbialites). The aim of this article is to analyze the possible implications of calcite precipitation produced in mats of Cladophora sp. in an Andean subtropical basin, considering it is the first time this phenomenon is described for the region. We collected samples from selected sites at the Lules River Basin, in four sampling dates between the years 2003 and 2004, within a monitoring work of 15 years. Samples were analyzed using an electron microscope and X-ray diffraction analysis. We found that Gomphonema sp. attached to Cladophora sp. contributes to precipitation of calcite and formation of microbialite like structures, in the studied area. This work presents an initial discussion of the discovery of microbialites-like structures attached to Cladophora sp. mats in a subtropical Andean stream and the environmental conditions that lead to their production, as well as the possible ecological implications of these microbialites.

Download Full-text

New Method for Nucleophilic Substitution on Hexachlorocyclotriphosphazene by Allylamine Using an Algerian Proton Exchanged Montmorillonite Clay (Maghnite-H+) as a Green Solid Catalyst

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.11.2.541.151-160 ◽

2016 ◽

Vol 11 (2) ◽

pp. 151 ◽

Cited By ~ 6

Author(s):

Lahouaria Medjdoub ◽

Belbachir Mohammed

Keyword(s):

Nucleophilic Substitution ◽

Room Temperature ◽

Montmorillonite Clay ◽

New Method ◽

Solid Catalyst ◽

H Nmr ◽

Flight Mass Spectrometry ◽

Crystalline Product ◽

First Time ◽

C Nmr

Nucleophilic substitution on hexachlorocyclotriphosphazene (HCCTP) with allylamine in order to give hexa(allylamino)cyclotriphosphazene (HACTP) is performed for the first time under mild conditions by using diethylether as solvent to replace benzene which is very toxic. The reaction time is reduced to half and also performed at room temperature but especially in the presence of an eco-catalyst called Maghnite-H+. This catalyst has a significant role in the industrial scale. In fact, the use of Maghnite is preferred for its many advantages: a very low purchase price compared to other catalysts, the easy removal of the reaction mixture. Then, Maghnite-H+ is became an excellent catalyst for many chemical reactions. The structure of HACTP synthesized in the presence of Maghnite-H+ to 5% by weight is confirmed by 1H-NMR, 13C-NMR, 31P-NMR (Nuclear magnetic resonance) and FTIR (Fourier Transform Infrared spectroscopy). MALDI-TOF (Matrix-Assisted Laser Desorption/Ionisation-time-of-flight mass spectrometry) is used to establish the molecular weight of HACTP which is 471 g/mol. DSC (Differential Scanning Calorimetery) and TGA (Thermogravimetric Analysis) show that HACTP is a crystalline product with a melting point of 88 °C. It is reactive after melting but is degraded from 230 °C. Copyright © 2016 BCREC GROUP. All rights reservedReceived: 28th September 2015; Revised: 5th December 2015; Accepted: 4th January 2016How to Cite: Medjdoub, L., Mohammed, B. (2016). New Method for Nucleophilic Substitution on Hexachlorocyclotriphosphazene by Allylamine Using an Algerian Proton Exchanged Montmorillonite Clay (Maghnite-H+) as a Green Solid Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2): 151-160 (doi:10.9767/bcrec.11.2.541.151-160)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.541.151-160

Download Full-text

Pharmacologic Activities¬ of 3’-Hydroxypterostilbene: Cytotoxic, Anti-Oxidant, Anti-Adipogenic, Anti-Inflammatory, Histone Deacetylase and Sirtuin 1 Inhibitory Activity

Journal of Pharmacy & Pharmaceutical Sciences ◽

10.18433/j33w4c ◽

2015 ◽

Vol 18 (4) ◽

pp. 713 ◽

Cited By ~ 7

Author(s):

Jody K Takemoto ◽

Connie M. Remsberg ◽

Neal M. Davies

Keyword(s):

Histone Deacetylase ◽

Inhibitory Activity ◽

Sirtuin 1 ◽

In Vitro Assays ◽

Naturally Occurring ◽

Anti Oxidant ◽

Anti Inflammatory ◽

First Time ◽

Stilbene Compounds

Purpose: Delineate the selected pharmacodynamics of a naturally occurring stilbene 3’-Hydroxypterostilbene. Objective: Characterize for the first time the pharmacodynamics bioactivity in several in-vitro assays with relevant roles in heart disease, inflammation, cancer, and diabetes etiology and pathophysiology. Methods: 3’-Hydroxypterostilbene was studied in in-vitro assays to identify possible bioactivity. Results: 3’-Hydroxypterostilbene demonstrated anti-oxidant, anti-inflammatory, cytotoxic, anti-adipogenic, histone deacetylase, and sirtuin-1 inhibitory activity. Conclusions: The importance of understanding individual stilbene pharmacologic activities were delineated. Small changes in chemical structure of stilbene compounds result in significant pharmacodynamic differences. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Download Full-text

Structural and In Silico Characterization of Small Molecules Isolated from Eichhornia crassipes

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/1375639 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Andrew Mtewa ◽

Duncan C. Sesaazi ◽

Fanuel Lampiao

Keyword(s):

In Silico ◽

Eichhornia Crassipes ◽

Cytochrome P450 Enzymes ◽

Anticancer Activities ◽

H Nmr ◽

Cytotoxic Compounds ◽

In Silico Characterization ◽

First Time ◽

Nonanedioic Acid

Eichhornia crassipes has been reported to have various medicinal properties including anticancer activities. The plant was collected from the Shire river in Malawi, and two cytotoxic compounds, benzene-1,4-diol and nonanedioic acid, were isolated and characterized for the first time in the leaves and roots of the plant. 1H NMR, COSY, HSQC, HMBC, 13-C, and LCMS spectroscopic experimental techniques were used to identify the compounds in their pure forms. In silico experiments showed that both compounds do not have AMES toxicity and do not inhibit cytochrome P450 enzymes, but nonanedioic acid acts as a CYP2D6 substrate. This work showed that Eichhornia crassipes can be considered to have a role as a source of potential hits and leads to drug development that can be rationally optimized for drugs.

Download Full-text

Three new species of Ophryotrocha (Annelida: Dorvilleidae) from a whale-fall in the North-East Atlantic

Zootaxa ◽

10.11646/zootaxa.2228.1.3 ◽

2009 ◽

Vol 2228 (1) ◽

pp. 43-56 ◽

Cited By ~ 45

Author(s):

HELENA WIKLUND ◽

ADRIAN G. GLOVER ◽

THOMAS G. DAHLGREN

Keyword(s):

Phylogenetic Analyses ◽

Nuclear Gene ◽

Close Relative ◽

North East ◽

The North ◽

Organic Carbon Flux ◽

Naturally Occurring ◽

Three New Species ◽

First Time ◽

Complex Organic

Three new Ophryotrocha species are described from sites with high levels of organic carbon flux including a whale-fall at 125 m depth off the Swedish coast and sediment sampled at 104 m depth beneath a fish farm in a Norwegian fjord. Phylogenetic analyses based on the nuclear gene H3 and the mitochondrial genes COI and 16S using MrBayes and Maximum Likelihood analyses show that Ophryotrocha eutrophila sp. nov. is a close relative to Ophryotrocha puerilis, while Ophryotrocha craigsmithi sp. nov. falls together with Palpiphitime lobifera, and Ophryotrocha scutellus sp. nov. occur within the 'hartmanni' clade. The genus Ophryotrocha is in our study monophyletic only if the genera Iphitime and Palpiphitime are included. Two representatives of Ophryotrocha previously described from anthropogenically-enriched sediments are here reported for the first time in very high abundance from a naturally occurring habitat. We suggest that whale falls are important habitats for the evolution of ecosystem services such as the degradation of complex organic compounds.

Download Full-text

Effect of Population Density of Pseudomonas fluorescens on Production of 2,4-Diacetylphloroglucinol in the Rhizosphere of Wheat

Phytopathology ◽

10.1094/phyto.1999.89.6.470 ◽

1999 ◽

Vol 89 (6) ◽

pp. 470-475 ◽

Cited By ~ 152

Author(s):

Jos M. Raaijmakers ◽

Robert F. Bonsall ◽

David M. Weller

Keyword(s):

Biological Control ◽

Population Density ◽

Supporting Evidence ◽

Pseudomonas Spp ◽

Fluorescent Pseudomonas ◽

Naturally Occurring ◽

Rhizosphere Population ◽

First Time ◽

Take All

The role of antibiotics in biological control of soilborne pathogens, and more generally in microbial antagonism in natural disease-suppressive soils, often has been questioned because of the indirect nature of the supporting evidence. In this study, a protocol for high pressure liquid chromatography/mass spectrometry is described that allowed specific identification and quantitation of the antibiotic 2,4-diacetylphloroglucinol (Phl) produced by naturally occurring fluorescent Pseudomonas spp. on roots of wheat grown in a soil suppressive to take-all of wheat. These results provide, for the first time, biochemical support for the conclusion of previous work that Phl-producing fluorescent Pseudomonas spp. are key components of the natural biological control that operates in take-all—suppressive soils in Washington State. This study also demonstrates that the total amount of Phl produced on roots of wheat by P. fluorescens strain Q2-87, at densities ranging from approximately 105 to 107 CFU/g of root, is proportional to its rhizosphere population density and that Phl production per population unit is a constant (0.62 ng/105 CFU). Thus, Phl production in the rhizosphere of wheat is strongly related to the ability of the introduced strain to colonize the roots.

Download Full-text

Comparative Study of Chemical Composition and Biological Activity of Yellow, Green, Brown, and Red Brazilian Propolis

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2016/6057650 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 27

Author(s):

Christiane Schineider Machado ◽

João Benhur Mokochinski ◽

Tatiana Onofre de Lira ◽

Fátima de Cassia Evangelista de Oliveira ◽

Magda Vieira Cardoso ◽

...

Keyword(s):

Biological Activity ◽

Chemical Composition ◽

Quality Standard ◽

Antimicrobial Activities ◽

Mato Grosso ◽

Gram Positive Bacteria ◽

H Nmr ◽

Chemical Profiles ◽

Brazilian Propolis ◽

First Time

The chemical composition and biological activity of a sample of yellow propolis from Mato Grosso do Sul, Brazil (EEP-Y MS), were investigated for the first time and compared with green, brown, and red types of Brazilian propolis and with a sample of yellow propolis from Cuba. Overall, EEP-Y MS had different qualitative chemical profiles, as well as different cytotoxic and antimicrobial activities when compared to the other types of propolis assessed in this study and it is a different chemotype of Brazilian propolis. Absence of phenolic compounds and the presence of mixtures of aliphatic compounds in yellow propolis were determined by analysing1H-NMR spectra and fifteen terpenes were identified by GC-MS. EEP-Y MS showed cytotoxic activity against human tumour strain OVCAR-8 but was not active against Gram-negative or Gram-positive bacteria. Our results confirm the difficulty of establishing a uniform quality standard for propolis from diverse geographical origins. The most appropriate pharmacological applications of yellow types of propolis must be further investigated.

Download Full-text