Jump to main content
Jump to site search

Issue 11, 2010
Previous Article Next Article

Photosensitized cleavage of plasmidic DNA by norharmane, a naturally occurring β-carboline

Author affiliations

Abstract

UV-A radiation (320–400 nm) induces damages to the DNA molecule and its components through photosensitized reactions. β-Carbolines (βCs), heterocyclic compounds widespread in biological systems, participate in several biological processes and are able to act as photosensitizers. The photosensitization of plasmidic DNA by norharmane in aqueous solution under UV-A radiation was studied. The effect of pH was evaluated and the participation of reactive oxygen species (ROS), such as hydroxyl radical (HO˙), superoxide anion (O2˙) and singlet oxygen (1O2) was investigated. A strong dependence of the photosensitized DNA relaxation on the pH was observed. The extent of the reaction was shown to be higher in the experiments performed at pH 4.7 than those performed at pH 10.2. As was expected, an intermediate extent of the reaction was observed at physiological pH (pH 7.4). Kinetic studies using ROS scavengers revealed that the chemical reactions between ROS and DNA are not the main pathways responsible for the damage of DNA. Consequently, the predominant mechanism yielding the DNA strand break takes place most probably via a type I mechanism (electron transfer) from the single excited state (S1) of the protonated form of norharmane (1[nHoH+]*). Additional information about the nature of the norharmane electronic excited states involved in the photocleavage reaction was obtained by using the N-methyl derivative of norharmane (N-methyl-norharmane).

Graphical abstract: Photosensitized cleavage of plasmidic DNA by norharmane, a naturally occurring β-carboline

Back to tab navigation

Supplementary files

Publication details

The article was received on 04 Feb 2010, accepted on 16 Mar 2010 and first published on 09 Apr 2010


Article type: Paper
DOI: 10.1039/C002235G
Org. Biomol. Chem., 2010,8, 2543-2552

  •   Request permissions

    Photosensitized cleavage of plasmidic DNA by norharmane, a naturally occurring β-carboline

    M. M. Gonzalez, M. Pellon-Maison, M. A. Ales-Gandolfo, M. R. Gonzalez-Baró, R. Erra-Balsells and F. M. Cabrerizo, Org. Biomol. Chem., 2010, 8, 2543
    DOI: 10.1039/C002235G

Search articles by author

Spotlight

Advertisements