Jump to main content
Jump to site search

Issue 36, 2017, Issue in Progress
Previous Article Next Article

Properties of a flavonol-based photoCORM in aqueous buffered solutions: influence of metal ions, surfactants and proteins on visible light-induced CO release

Author affiliations

Abstract

The properties of the extended flavonol 3-hydroxy-2-phenyl-benzo[g]chromen-4-one (2a) in DMSO : aqueous buffer solutions at pH = 7.4, including in the presence of metal ions, surfactants and serum albumin proteins, have been examined. Absorption and emission spectral studies of 2a in 1 : 1 DMSO : PBS buffer (pH = 7.4) indicate that a mixture of neutral and anionic forms of the flavonol are present. Notably, in 1 : 1 DMSO : TRIS buffer (pH = 7.4) only the neutral form of the flavonol is present. These results indicate that the nature of the buffer influences the acid/base equilibrium properties of 2a. Introduction of a Zn(II) complex of 2a to a 1 : 1 DMSO : aqueous buffer (TRIS or PBS, pH = 7.4) solution produces absorption and emission spectral features consistent with the presence of a mixture of neutral 2a along with Zn(II)-coordinated or free 2a. The nature of the anionic species present depends on the buffer composition. PBS buffered solutions (pH = 7.4) containing the surfactants CTAB or SDS enable 2a to be solubilized at a much lower percentage of DMSO (3.3–4.0%). Solutions containing the cationic surfactant CTAB include a mixture of 2a and 2a whereas only the neutral flavonol is present in SDS-containing buffered solution. Compound 2a is also solubilized in TRIS buffer solutions at low cocentrations of DMSO (3.3%, pH = 7.4) in the presence of serum albumin proteins. Stern–Volmer analysis of the quenching of the inherent protein fluorescence indicates static binding of 2a to the proteins. The binding constant for this interaction is lower than that found for naturally-occurring flavonols (quercetin or morin) or 3-hydroxyflavone. Compound 2a binds to Site I of bovine and human serum albumin proteins as indicated by competition studies with warfarin and ibuprofen, as well as by docking investigations. The quantum yield for CO release from 2a (λirr = 419 nm) under aqueous conditions ranges from 0.0006(3) when the compound is bound to bovine serum albumin to 0.017(1) when present as a zinc complex in a 1 : 1 DMSO : H2O solution. Overall, the results of these studies demonstrate that 2a is a predictable visible light-induced CO release compound under a variety of aqueous conditions, including in the presence of proteins.

Graphical abstract: Properties of a flavonol-based photoCORM in aqueous buffered solutions: influence of metal ions, surfactants and proteins on visible light-induced CO release

Back to tab navigation

Supplementary files

Publication details

The article was received on 04 Mar 2017, accepted on 10 Apr 2017 and first published on 19 Apr 2017


Article type: Paper
DOI: 10.1039/C7RA02653F
Citation: RSC Adv., 2017,7, 21997-22007
  • Open access: Creative Commons BY-NC license
  •   Request permissions

    Properties of a flavonol-based photoCORM in aqueous buffered solutions: influence of metal ions, surfactants and proteins on visible light-induced CO release

    M. Popova, T. Soboleva, Atta M. Arif and L. M. Berreau, RSC Adv., 2017, 7, 21997
    DOI: 10.1039/C7RA02653F

    This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material and it is not used for commercial purposes.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements