fulltext.study @t Gmail

Probing solute–solvent hydrogen bonding with fluorescent water-soluble curcuminoids

Paper ID Volume ID Publish Year Pages File Format Full-Text
27034 43996 2010 10 PDF Available
Title
Probing solute–solvent hydrogen bonding with fluorescent water-soluble curcuminoids
Abstract

Glycosylated water-soluble curcuminoids (C1–C3, first scheme of this article) differing in the 3,3′-ring substituents (–OH, –OCH3 and H) equilibrate between the di-keto and the keto–enol forms. The former are well observable in the absorption spectra in water, but their emissions are always negligible. The keto–enol forms of C1–C3 exhibit a broad range of fluorescence quantum yields in different solvents, organic and water: formation of solute–solvent hydrogen bonds through the 3,3′-ring substituents may change the radiationless S1-state decay constant by up to a factor 200. Such a fluorescence quenching mechanism is extremely efficient in water and, for C1, in accepting organic media. On the contrary, no effects traceable to intermolecular hydrogen bonds involving the central β-dicarbonyl moiety have been observed. So, fluorescence of these curcuminoids may probe the hydrogen bonding ability, particularly as acceptor, of their microenvironments, including hydrophilic/hydrophobic domains in complex biological systems. Interaction of C1 and C2 with bovine serum albumin results in emission enhancements inverse to the quantum yields of the curcuminoids in water. The observations support the idea that, although the curcuminoid microenvironment within its complex with the protein is less polar and hydrogen bonding than water itself, residual water/ligand hydrogen bonds are active in enhancing radiationless transitions. Finally, fluorescence confocal images of HCT116 cells treated with C1–C3 suggest the apparently small structural differences to affect, besides their fluorescence behaviour, their interactions and fate within living cells.

Keywords
31.50.Df (excited states atomic and molecular); 33.50.Dq (fluorescence of molecules); 33.15.Fm (hydrogen bonding in molecules); 31.70.Dk (solvent effects in atomic and molecular interactions)Curcuminoid; Photophysics; Solvent effects; Hydrogen bonding; Ra
First Page Preview
Probing solute–solvent hydrogen bonding with fluorescent water-soluble curcuminoids
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 210, Issues 2–3, 25 February 2010, Pages 115–124
Authors
, , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us