Fast repair of hydroxy radical purine deoxynucleotide adducts by phenylpropanoid glycosides and their derivatives from Chinese herbs.
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 very significant to look for ways in which either oxygen radicals are scavenged prior to DNA damage or damaged DNA is repaired to supplement the cells' inadequate repair capacity. The repair activities and reaction mechanism of phenylpropanoid glycosides (PPGs) and their derivatives, isolated from Chinese folk medicinal herbs, towards both dGMP-OH* adducts and dAMP-OH* adducts were studied with the pulse radiolytic technique. On pulse irradiation of nitrous oxide saturated 2 mM dGMP or dAMP aqueous solution containing one of the PPGs or their derivatives, the transient absorption spectra of the hydroxyl adduct of dGMP or dAMP decayed with the formation of that of phenoxyl radicals of PPGs or their derivatives within several decades of microseconds after electron pulse irradiation. The result indicated that dGMP or dAMP hydroxyl adducts can be repaired by PPGs or their derivatives. The rate constants of the repair reactions were deduced to be 0.641-1.28 x 10(9) M(-1) s(-1) for dGMP-OH* and 0.2-0.491 x 10(9) M(-1) s(-1) for dAMP-OH*, which positively correlated to the number of phenolic hydroxyl groups in the glycoside structure. A deeper understanding of this new repair mechanism may help researchers to design strategies to prevent and/or intervene more effectively in free radical related diseases.
Shi
Y
Y
Department of Biology, Lanzhou University, PR China.
Lin
W
W
Fan
B
B
Jia
Z
Z
Yao
S
S
Kang
J
J
Wang
W
W
Zheng
R
R
D018736:DNA Adducts; D004260:DNA Repair; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D006027:Glycosides / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000378:metabolism*; D010636:Phenols / Q000494:pharmacology; D010666:Phenylpropionates / Q000494:pharmacology*
D018736:DNA Adducts; D004365:Drugs, Chinese Herbal; D006027:Glycosides; D010636:Phenols; D010666:Phenylpropionates; D017665:Hydroxyl Radical