Chemical structure determination of DNA bases modified by active metabolites of lucidin-3-O-primeveroside.

Lucidin-3-O- primeveroside (LuP) is one of the components of madder root (Rubia tinctorum L.; MR) which is reported to be carcinogenic in the kidney and liver of rats. Since metabolism of LuP generates genotoxic compounds such as lucidin (Luc) and rubiadin (Rub), it is likely that LuP plays a key role in MR carcinogenesis. In the present study, the chemical structures of Luc-specific 2′-deoxyguanosine (dG) and 2′-deoxyadenosine (dA) adducts following the reactions of dG and dA with a Luc carbocation or quinone methide intermediate derived from Acetoxy-Luc were determined by liquid chromatography with photodiode array and electron spray ionizaion−mass spectrometry (LC-PDA-ESI/MS). The identification of the two measurable adducts as Luc-N2-dG and Luc-N6-dA was confirmed by NMR analysis. Subsequently, using a newly developed quantitative analytical method using LC-ESI/MS, the formation of Luc-N2-dG and Luc-N6-dA from the reaction of calf thymus DNA with Luc in the presence of S9 mixture was observed. The fac...