| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 30918 | Journal of Photochemistry and Photobiology B: Biology | 2011 | 5 Pages |
The photosensitized oxidation of guanine (G) by the triplet state of xanthone (XT) and the repair for photo-damaged G(–H) by ferulic acid (FCA) were investigated using the laser flash photolysis technique. The rate constants of the reaction of triplet state of XT with G and with FCA were determined as 4.5 × 109 and 8.0 × 109 L mol−1 s−1, respectively. Laser exposure was performed on the N2-saturated acetonitrile/water (v/v, 1:1) solution containing G, XT and FCA. The transient absorption spectra indicated that the triplet state of XT first reacted with G predominantly to form the oxidized radical G(–H). The radical G(–H) was rapidly repaired by FCA, and the rate constant for the repair reaction was determined as 1.1 × 109 L mol−1 s−1. These results demonstrated that non-enzymatic repair is a feasible method for repairing photosensitized DNA bases oxidation.
► The triplet state of xanthone (XT) reacted with guanine (G) by hydrogen transfer. ► The triplet state of xanthone (XT) reacted with ferulic acid (FCA) by electron transfer. ► The triplet state of XT first reacted with G to form the oxidized radical G(–H), which were then fast repaired by FCA.
