Who is the king? The alpha-hydroxy-beta-oxo-alpha,beta-enone moiety or the catechol B ring: relationship between the structure of quercetin derivatives and their pro-oxidative abilities.
Quercetin and other flavonoids have been reported to exhibit both antioxidant and pro-oxidant properties. Most studies about the pro-oxidative ability were conducted in the presence of metal ions, and the essential functional moiety of quercetin responsible for the pro-oxidative effect is still unclear. In this study, we evaluated the pro-oxidative abilities in the absence of metal ions of two quercetin derivatives, i.e., quercetin-3'-O-beta-D-glucoside (1) and quercetin-3-O-beta-D-glucoside (2), by assessing DNA cleavage and HO(*)-radical production. The binding mode between these compounds and DNA was studied by fluorescence and viscometric titrations. The results showed that 1 can efficiently induce oxidative damage to plasmid DNA, while 2 shows poor activity. Both 1 and 2 bind to DNA via groove-binding. These results proved that the alpha-hydroxy-beta-oxo-alpha,beta-enone moiety contributes to the pro-oxidative activity of quercetin.
Liu
Pei-Yan
PY
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P R China.
Li
Kun
K
Zhang
Ji
J
Zhang
Da-Wei
DW
Lin
Hong-Hui
HH
Yu
Xiao-Qi
XQ
D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D002396:Catechols / Q000737:chemistry*; D053837:DNA Cleavage / Q000187:drug effects; D017665:Hydroxyl Radical / Q000378:metabolism; D008670:Metals / Q000737:chemistry; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D013050:Spectrometry, Fluorescence
D000975:Antioxidants; D002396:Catechols; D008670:Metals; C016527:isoquercitrin; D017665:Hydroxyl Radical; D011794:Quercetin; C034221:catechol