The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform

Laszlo Biczok - One of the best experts on this subject based on the ideXlab platform.

  • inclusion complex formation of ionic liquids with 4 sulfonatocalixarenes studied by competitive binding of Berberine Alkaloid fluorescent probe
    Chemical Physics Letters, 2009
    Co-Authors: Zsombor Miskolczy, Laszlo Biczok
    Abstract:

    Abstract A clinically important natural isoquinoline Alkaloid, Berberine, was used as a fluorescent probe to study the encapsulation of 1-alkyl-3-methylimidazolium (CnMIm+) type ionic liquids in 4-sulfonato-substituted calix[4]arene (SCX4) and calix[6]arene (SCX6) at pH 2. Addition of ionic liquids to the aqueous solution of Berberine−SCXn inclusion complexes brought about considerable fluorescence intensity diminution due to the extrusion of Berberine from the macrocycle into the aqueous phase by the competitive inclusion of CnMIm+ cation. The lengthening of the aliphatic side chain of the imidazolium moiety diminished the equilibrium constant of complexation with SCX4, but enhanced the stability of SCX6 complexes. Larger binding strength was found for SCX4.

  • highly sensitive fluorescence response to inclusion complex formation of Berberine Alkaloid with cucurbit 7 uril
    Journal of Physical Chemistry C, 2008
    Co-Authors: Monika Megyesi, Laszlo Biczok, Istvan Jablonkai
    Abstract:

    The effect of inclusion complex formation on the fluorescence properties of Berberine, a clinically important natural Alkaloid, was studied using cucurbit[7]uril as macrocyclic host compound. The formation of a very stable 1:1 inclusion complex led to about 500-fold fluorescence intensity enhancement, which facilitated the detection of Berberine even below nanomolar concentration. Addition of NaCl caused a significant change in the association constant and the fluorescence characteristics of the complex, whereas the variation of the anion had a small effect. 1-Alkyl-3-methylimidazolium type ionic liquids altered the fluorescent properties of the Berberine−cucurbit[7]uril complex much more efficiently than did NaCl. Time-resolved fluorescence studies showed ternary complex formation. Because Berberine fluorescence is insensitive to pH and increases substantially upon inclusion in cucurbit[7]uril, the reversible self-assembly of this host−guest pair may find analytical application in enzyme assays.

  • Berberine Alkaloid as a sensitive fluorescent probe for bile salt aggregates
    Journal of Physical Chemistry B, 2007
    Co-Authors: Monika Megyesi, Laszlo Biczok
    Abstract:

    Effect of sodium cholate (NaC) bile salt on the absorption and fluorescence properties of Berberine cation was studied in aqueous solution and water-cosolvent mixtures. The alteration of the fluorescent behavior with increasing NaC concentration showed an entirely different trend from that found previously in the presence of sodium dodecylsulfate. Binding to bile salt agglomerates led to significant fluorescence intensity enhancement, and the fluorescence lifetime of Berberine proved to be highly sensitive to the structure and size of the aggregates. The dual exponential decay kinetics above 10 mM NaC concentration showed that the probe resided in two totally different binding sites. At 2-10 mM NaC concentrations, only primary aggregates were detected. The aggregate disrupting power of cosolvents decreased in the series of dimethylformamide, acetonitrile, formamide, and methanol. These compounds enhanced the water accessibility of Berberine bound to aggregates and diminished the number of secondary aggregates.

Monika Megyesi - One of the best experts on this subject based on the ideXlab platform.

  • highly sensitive fluorescence response to inclusion complex formation of Berberine Alkaloid with cucurbit 7 uril
    Journal of Physical Chemistry C, 2008
    Co-Authors: Monika Megyesi, Laszlo Biczok, Istvan Jablonkai
    Abstract:

    The effect of inclusion complex formation on the fluorescence properties of Berberine, a clinically important natural Alkaloid, was studied using cucurbit[7]uril as macrocyclic host compound. The formation of a very stable 1:1 inclusion complex led to about 500-fold fluorescence intensity enhancement, which facilitated the detection of Berberine even below nanomolar concentration. Addition of NaCl caused a significant change in the association constant and the fluorescence characteristics of the complex, whereas the variation of the anion had a small effect. 1-Alkyl-3-methylimidazolium type ionic liquids altered the fluorescent properties of the Berberine−cucurbit[7]uril complex much more efficiently than did NaCl. Time-resolved fluorescence studies showed ternary complex formation. Because Berberine fluorescence is insensitive to pH and increases substantially upon inclusion in cucurbit[7]uril, the reversible self-assembly of this host−guest pair may find analytical application in enzyme assays.

  • Berberine Alkaloid as a sensitive fluorescent probe for bile salt aggregates
    Journal of Physical Chemistry B, 2007
    Co-Authors: Monika Megyesi, Laszlo Biczok
    Abstract:

    Effect of sodium cholate (NaC) bile salt on the absorption and fluorescence properties of Berberine cation was studied in aqueous solution and water-cosolvent mixtures. The alteration of the fluorescent behavior with increasing NaC concentration showed an entirely different trend from that found previously in the presence of sodium dodecylsulfate. Binding to bile salt agglomerates led to significant fluorescence intensity enhancement, and the fluorescence lifetime of Berberine proved to be highly sensitive to the structure and size of the aggregates. The dual exponential decay kinetics above 10 mM NaC concentration showed that the probe resided in two totally different binding sites. At 2-10 mM NaC concentrations, only primary aggregates were detected. The aggregate disrupting power of cosolvents decreased in the series of dimethylformamide, acetonitrile, formamide, and methanol. These compounds enhanced the water accessibility of Berberine bound to aggregates and diminished the number of secondary aggregates.

Istvan Jablonkai - One of the best experts on this subject based on the ideXlab platform.

  • highly sensitive fluorescence response to inclusion complex formation of Berberine Alkaloid with cucurbit 7 uril
    Journal of Physical Chemistry C, 2008
    Co-Authors: Monika Megyesi, Laszlo Biczok, Istvan Jablonkai
    Abstract:

    The effect of inclusion complex formation on the fluorescence properties of Berberine, a clinically important natural Alkaloid, was studied using cucurbit[7]uril as macrocyclic host compound. The formation of a very stable 1:1 inclusion complex led to about 500-fold fluorescence intensity enhancement, which facilitated the detection of Berberine even below nanomolar concentration. Addition of NaCl caused a significant change in the association constant and the fluorescence characteristics of the complex, whereas the variation of the anion had a small effect. 1-Alkyl-3-methylimidazolium type ionic liquids altered the fluorescent properties of the Berberine−cucurbit[7]uril complex much more efficiently than did NaCl. Time-resolved fluorescence studies showed ternary complex formation. Because Berberine fluorescence is insensitive to pH and increases substantially upon inclusion in cucurbit[7]uril, the reversible self-assembly of this host−guest pair may find analytical application in enzyme assays.

Nilmoni Sarkar - One of the best experts on this subject based on the ideXlab platform.

  • unveiling the mode of interaction of Berberine Alkaloid in different supramolecular confined environments interplay of surface charge between nano confined charged layer and dna
    Journal of Physical Chemistry B, 2016
    Co-Authors: Niloy Kundu, Arpita Roy, Debasis Banik, Nilmoni Sarkar
    Abstract:

    In this Article, we demonstrate a detailed characterization of binding interaction of Berberine chloride (BBCl) with calf-thymus DNA (CT-DNA) in buffer solution as well as in two differently charged reverse micelles (RMs). The photophyscial properties of this Alkaloid have been modulated within these microheterogeneous bioassemblies. The mode of binding of this Alkaloid with DNA is of debate to date. However, fluorescence spectroscopic measurements, circular dichroism (CD) measurement, and temperature-dependent study unambiguously establish that BBCl partially intercalates into the DNA base pairs. The nonplanarity imposed by partial saturation in their structure causes the nonclassical types of intercalation into DNA. Besides the intercalation, electrostatic interactions also play a significant role in the binding between BBCl and DNA. DNA structure turns into a condensed form after encapsulation into RMs, which is followed by the CD spectra and microscopy study. The probe location and dynamics in the nan...

Zsombor Miskolczy - One of the best experts on this subject based on the ideXlab platform.

  • inclusion complex formation of ionic liquids with 4 sulfonatocalixarenes studied by competitive binding of Berberine Alkaloid fluorescent probe
    Chemical Physics Letters, 2009
    Co-Authors: Zsombor Miskolczy, Laszlo Biczok
    Abstract:

    Abstract A clinically important natural isoquinoline Alkaloid, Berberine, was used as a fluorescent probe to study the encapsulation of 1-alkyl-3-methylimidazolium (CnMIm+) type ionic liquids in 4-sulfonato-substituted calix[4]arene (SCX4) and calix[6]arene (SCX6) at pH 2. Addition of ionic liquids to the aqueous solution of Berberine−SCXn inclusion complexes brought about considerable fluorescence intensity diminution due to the extrusion of Berberine from the macrocycle into the aqueous phase by the competitive inclusion of CnMIm+ cation. The lengthening of the aliphatic side chain of the imidazolium moiety diminished the equilibrium constant of complexation with SCX4, but enhanced the stability of SCX6 complexes. Larger binding strength was found for SCX4.