Fast repair of dAMP hydroxyl radical adduct by verbascoside via electron transfer

DNA damaged by oxygen radicals has been implicated as a causative event in a number of degenerative diseases, including cancer and aging. So it is ver y impotent to look for ways in which either oxygen radicals are scavenged p rior to DNA damage or damaged DNA is repaired to supplement the cells' inad equate repair capacity. The repair activity and its mechanism of verbascosi de, isolated from Pedicularis species, towards dAMP-OH . was studied with p ulse radiolytic technique. On pulse irradiation of nitrous oxide saturated 2 mmol/L dAMP aqueous solution containing verbascoside, the transient absor ption spectrum of the hydroxyl adduct of dAMP decayed with the formation of that of the phenoxyl radical of verbascoside well under 100 microseconds a fter electron pulse irradiation. The result indicated that dAMP hydroxyl ad ducts can be repaired by verbascoside. The rate constants of the repair rea ction was deduced to be 5.9 x 10(8) dm(3).mol(-1).s(-1). A deeper understan ding of this new repair mechanism will undoubtedly help researchers explore new prevent and/or intervening medicine.