Cyclic and non cyclic aliphatic–aromatic polyesters derived from biomass: Study of structures by MALDI-ToF and NMR

Balancing the transesterification reactivity of isosorbide with diphenyl carbonate: preferential activation of exo-OH

Exo-OH on ISB has long been asserted as a highly reactive moiety compared with endo-OH. Herein, we report that the nucleophilic attack surmounts steric hindrance in rendering endo-OH more reactive than exo-OH in case of transesterification with DPC.

Cellular effect of styrene substituted biscoumarin caused cellular apoptosis and cell cycle arrest in human breast cancer cells

BACKGROUND

Coumarins occurs naturally across plant kingdoms exhibits significant pharmacological properties and pharmacokinetic activity. The conventional, therapeutic agents are often associated with poor stability, absorption and increased side effects. Therefore, identification of a drug that has little or no-side effect on humans is consequential. Here, we investigated the antiproliferative activity of styrene substituted biscoumarin against various human breast cancer cell lines, such as MCF-7, (ER-) MDA-MB-231 and (AR+) MDA-MB-453. Styrene substituted biscoumarin induced cell death by apoptosis in MDA-MB-231 cell line was analyzed.

METHODS

Antiproliferative activity of Styrene substituted biscoumarin was performed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Styrene substituted biscoumarin induced apoptosis was assessed by Hoechst staining, Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) staining and flow cytometric analysis. Migratory and proliferating characteristic of breast cancer cell line MDA-MB-231 was also analyzed by wound healing and colony formation assay. Furthermore, mRNA expression of BAX and BCL-2 were quantified using qRT-PCR and protein expression level analyzed by Western blot.

RESULTS

The inhibition concentration (IC₅₀) of styrene substituted biscoumarin was assayed against three breast cancer cell lines. The inhibition concentration (IC₅₀) value of styrene substituted biscoumarin toward MDA-MB-231, MDA-MB-453 and MCF-7 cell lines was 5.63, 7.30 and 10.84μg/ml respectively. Styrene substituted biscoumarin induced apoptosis was detected by Hoechst staining, DAPI/PI analysis and flow-cytometric analysis. The migration and proliferative efficiency of MDA-MB-231 cells were completely arrested upon styrene substituted biscoumarin treatment. Also, mRNA gene expression and protein expression of pro-apoptotic (BAX) and anti-apoptotic (BCL-2) genes were analyzed by qRT-PCR and western blot analysis upon styrene substituted biscoumarin treatment to MDA-MB-231 cells. Our results showed that styrene substituted biscoumarin downregulated BCL-2 gene expression and upregulated BAX gene expression to trigger apoptotic process.

CONCLUSION

Styrene substituted biscoumarin could induce apoptosis through intrinsic mitochondrial pathway in breast cancer cell lines, particularly in MDA-MB-231. Our data suggest that styrene substituted biscoumarin may act as a potential chemotherapeutic agent against breast cancer.

Determination of molecular size parameters and quantification of polyacrylic acid by high performance size-exclusion chromatography with triple detection

Synthetic polyelectrolytes are a broad class of vaccine adjuvants. Among them, polyacrylic acid (PAA), a polyanionic polymer, is currently evaluated by Sanofi Pasteur. As chain length is considered to be a critical quality attribute for adjuvant properties of PAA, measurement of precise and accurate molecular size parameters is important for these polymers. In the field of synthetic polymer chemistry, methods for determination of molecular size parameters are well defined. Specifically, high performance size-exclusion chromatography (HPSEC) with multi-detection system is a method of choice. This paper describes the development of HPSEC method to well characterize and precisely quantify PAA in different adjuvant formulations. A first set of characterizations were made, with determination of dn/dc coefficient, which enabled the determination of weight- and number-average molecular weight, viscosimetric radius, and intrinsic viscosity. In-depth characterization was also made with branching study through the use of Mark-Houwink parameter determination. The quantification method was also evaluated according to validation method-like criteria: limit of detection and limit of quantification, repeatability, accuracy, and specificity with recombinant surface glycoprotein gB from human cytomegalovirus (CMV-gB) as model antigen.

Biobased polyesters and other polymers from 2,5-furandicarboxylic acid: a tribute to furan excellency

A tribute to 2,5-furandicarboxylic acid excellency and the myriad of novel polyesters, as well as polyamides, among other polycondensates, is comprehensively paid.

Facile Synthesis, Characterization, and In Vitro Antimicrobial and Anticancer Activities of Biscoumarin Copolyester Bearing Pendant 3-(Trifluoromethyl)Styrene

Synthesis of random biscoumarin copolyester bearing pendant 3-(trifluoromethyl)styrene was prepared by the reaction of biscoumarin monomer 3 and hydroquinone 5 with azeloyl chloride. The influence of pendant 3-(trifluoromethyl)styrene unit on the properties of copolyester such as inherent viscosity, solubility, and thermal stability was investigated and compared in detail. The inherent viscosity and polydispersity index of the copolyester were found to be 0.15 dL/g and 1.36, respectively. The chemical structure of the copolyester was investigated by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. The physical properties of copolyester were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and X-ray diffraction (XRD) technique. Agar disc diffusion method was employed to study the antimicrobial activity of the random copolyester. In vitro anticancer activity against lung cancer (Hep-2) cell line was also investigated.

Hyperbranched cyclic and multicyclic poly(etherketone)s by polycondensation of isosorbide and isomannide with 2,6,4′-trifluorobenzophenone and 1,3,5-tris(4-fluorobenzoyl) benzene

1,3,5-Tris(4-fluorobenzoyl)benzene (TFBB) and 2,6,4′-trifluorobenzophenone (TFB) were polycondensed with isosorbide and isomanide. All polycondensations were performed in a mixture of dimethyl sulfoxide and toluene with potassium carbonate as promotor. Optimal concentration to avoid gelation was set at 0.06 mol L−1. The different cyclization tendencies on the basis of monomers conformations are discussed. In the TFB series, the feed ratio isosorbide/TFB was varied from 1.0:1.0 to 1.5:1.0. A majority of linear and hyperbranched species were identified as main reaction products by matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry regardless of the diol with slight cyclization tendency for isomannide. When TFBB was polycondensed with isosorbide, the cyclization tendency was significantly improved. The products obtained at a feed ratio of 1.41/1.0 and 1.51/1.0 were rich in cyclic and multicyclic species. More interesting results were obtained from the polycondensation of TFBB and isomannide, giving rise majoritarily to cyclic, bicyclic, and multicyclic species. Differential scanning calorimetric measurements indicated high glass transition temperature (around 200°C).

RAFT polymerization of bio-based 1-vinyl-4-dianhydrohexitol-1,2,3-triazole stereoisomers obtained via click chemistry

Four 1-vinyl-4-dianhydrohexitol-1,2,3-triazole stereoisomers are prepared from isomannide, isoidide, and isosorbide using an alkylation/CuAAC-ligation/elimination three-step strategy. After characterization of the monomers by NMR, differential scanning calorimetry (DSC), and high-resolution mass spectrometry (HRMS), the corresponding stereocontrolled poly(1-vinyl-4-dianhydrohexitol-1,2,3-triazole)s are obtained by RAFT polymerization using a xanthate chain transfer agent. A systematic investigation of the structure-properties relationship of both the monomers and polymers highlights the significant impact of the dianhydrohexitols stereochemistry on their physical properties (1H and 13C NMR chemical shifts, physical state, Tg, thermal stability and solubility). A particularly original and unexpected behavior is highlighted since the two different isosorbide-based poly(1-vinyl-4-dianhydrohexitol-1,2,3-triazole) stereoisomers exhibit contrasting solubility in water.

1,4:3,6-Dianhydrohexitols: Original platform for the design of biobased polymers using robust, efficient, and orthogonal chemistry

1,4:3,6-Dianhydrohexitols (DAHs) are nontoxic and sustainable diols that have been extensively applied as monomers for the preparation of polymer materials by step-growth polymerization processes. The presence of two reactive alcohol groups was exploited to design a library of symmetric and asymmetric stereocontrolled alkyne- and/or azide-functionalized AA/BB and AB monomers suitable for thermal or copper(I)-catalyzed azide-alkyne cycloaddition (TAAC and CuAAC). Step-growth polymerization of these monomers yielded a series of linear polytriazoles as well as partially biosourced networks using a combination of AB + A2B2 derivatives. Characterization of the resulting materials allowed for the establishment of a thorough structure–property relationship emphasizing the impact of monomer stereochemistry and cycloaddition regioselectivity on materials properties.