Antioxidant properties of resveratrol on DNA components photooxidation

NEYRA RECKY, JAEL; GASPAR TOSATO, MAIRA; SERRANO, MARIANA PAULA; THOMAS, ANDRÉS H.; DANTOLA, MARIA LAURA; LORENTE, CAROLINA

La Plata

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Biofísica; 2018

Sociedad Argentina de Biofísica

Alarge number of physicochemical changes were described in photodynamicallytreated DNA molecules, including conformational changes and cleavage. Thesechanges are a consequence of the photooxidation of the nucleotides, especiallythose that contain guanine bases.Pterin(Ptr) is a natural compound that under UV-A radiation is photoactive, andphotoinduces the degradation of biomolecules.1 It was previouslydemonstrated that Ptr is able to damage DNA and nucleotides by both type I and typeII mechanisms. Moreover, under UV-A irradiation in the presence of Ptr, a supercoiledpUC18 plasmid suffers a fast relaxation followed by linearization (evidencingbreaks) at longer irradiation times.2Resveratrol(trans-3,5,4′-trihydroxy-stilbene; RSV) is a natural polyphenolic compound3,which can be found in different plant species and it is synthesized in responseto UV radiation, fungal infections, oxidative stress and mechanical damage. Thetherapeutic potential of RSV and their derivatives has been widely studied, dueto their antiviral, cardioprotective, anticancer, antiinflammatory andantioxidant properties. However, not much is known about their antioxidantability in radiation mediated processes. For this reason, the main goal of thiswork is to evaluate if RSV can prevent the photosensitized oxidation of DNA. Tocarry out this study, aqueous solutions of nucleotides and Ptr (pH 6, roomtemperature) were exposed to UV-A radiation (lex=365nm) during different times in presence and absence of RSV. The photochemicalreaction was studied by UV-Vis spectrophotometry, HPLC, fluorescencespectroscopy, mass spectrometry and laser flash photolysis. Resultsindicate that the photoinduced damage of nucleotides is reduced in the presenceof RSV, noticing that, under certain concentrations, the photodamage process isinhibited. The mechanistic study indicates that in our experimental conditions,although RSV is capable to deactivate the triplet excited state of Ptr, the inhibitionof the photosensitized process is due to the deactivation of nucleotide radicals. Aknowledgements: J.R.N.R. thanks ANPCyT for doctoralresearch fellowship. M:G:T thanks CONICET for postdoctoral research fellowship.M:P:S., A.H.T., M:L:D., and C.L. are research members of CONICET. Grants:CONICET-PIP 112-200901-0304, ANPCyT-PICT 2012?0508 and 2015-1988, UNLP-GrantX712. 1. Lorente C., Thomas, A.H., Acc. Chem.Res., 39, 395 (2006)2. Lorente C., et. al., Pteridines, 11, 100 (2000).3. Quideau S., et al, Angew. Chem. Int. Ed. 50, 586 (2011)