Antioxidant properties of resveratrol on DNA components photooxidation

NEYRA RECKY, JAEL R.; GASPAR TOSATO, MAIRA; SERRANO, MARIANA P; THOMAS, ANDRÉS HÉCTOR; DANTOLA, MARIA LAURA; LORENTE, CAROLINA

La Plata

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

Sociedad Argentina de Biofísica

A large 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 previously demonstratedthat Ptr is able to damage DNA and nucleotides by both type I and type IImechanisms. Moreover, under UV-A irradiation in the presence of Ptr, asupercoiled pUC18 plasmid suffers a fast relaxation followed by linearization(evidencing breaks) at longer irradiation times.2Resveratrol (RSV) is a natural polyphenolic compound3, which can be found indifferent plant species. The therapeutic potential of RSV has been widely studied,due to its antiviral, cardioprotective, anticancer, antiinflammatory and antioxidantproperties. However, not much is known about its antioxidant ability in radiationmediated processes. The main goal of this work is evaluate if RSV can prevent thephotosensitized oxidation of DNA.Aqueous solutions of nucleotides and Ptr (pH 6, room temperature) were exposedto UV-A radiation (lex=365 nm) during different times in presence and absence ofRSV. The photochemical reaction was studied by UV-Vis spectrophotometry, HPLC,fluorescence spectroscopy, mass spectrometry and laser flash photolysis.Results indicate that the photoinduced damage of nucleotides is reduced in thepresence of RSV, noticing that, under certain concentrations, the photodamageprocess is inhibited. The mechanistic study indicates that, although RSV is capableto deactivate the triplet excited state of Ptr, the inhibition of the photosensitizedprocess is due to the deactivation of nucleotide radicals.References1. 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)AcknowldegmentsJ.R.N.R. thanks ANPCyT for a doctoral research fellowship. M.G.T thanks CONICET for a postdoctoralresearch fellowship. M.P.S., A.H.T., M.L.D., and C.L. are research members of CONICET. Grants: CONICETPIP112-200901-0304, ANPCyT-PICT 2012?0508 and 2015-1988, UNLP-Grant X712.59