Antioxidant action of Resveratrol in the prevention of guanine photosensitized oxidation

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

Viña del Mar

Congreso; 14th Encuentro Latinoamericano de Fotoquímica y Fotobiología, XIV ELAFOT; 2019

Universidad Andrés Bello, Pontificia Universidad Católica de Chile, Universidad de Santiago de Chile, Universidad de Chile

Resveratrol (3,4´,5,-trihydroxystilbene, RSV) is a natural polyphenolic compound naturally presentin a variety of plant species, especially in fruits and flowers such as grapevines, nuts, lilly flowers,and it is synthesized in response to stress situations such as infections or UV radiation.1,2 During thelast years, the interest in RSV has increased due tothe evidences found of many beneficial propertiesagainst aging and for the prevention and/or treatmentof various diseases such as cancer, Alzheimer andcardiac dysfunction3-6It has been reported that pterin(Ptr), is able to photosensitize the degradation of thepurine nucleotide 2?-deoxyguanosine 5?-monophosphate (dGMP) in aqueous solution.7,8 Inacidic conditions the main mechanism of this processis type I mechanism, and is initiated with an electrontransfer from dGMP to triplet excited state of Ptr (3Ptr*), where the guanine radical cation(dGMP?+) is formed (Scheme).9 This radical undergoes fast deprotonation to form the neutralradical (dGMP(-H+)?), which as previously described by Cadet et al, is the origin of oxidativedamage on DNA molecules from one-electron oxidation by diverse chemical or physical oxidizingagents, and in aqueous media suffers nucleophilic addition or deprotonation reactions yieldingseveral products.10Kinetic analysis (HPLC-UV, UPLC-MS) during steady-state irradiation (λIRR = 365 nm)) indicatesthat RSV protects dGMP from oxidation. By fluorescence and laser flash photolysis experiments(LP980, Edinburgh) the bimolecular quenching rate constants of 1Ptr*, 3Ptr* and dGMP(-H+)? withRSV were determined (1.1(±0.1)x1010s-1M-1, 4.94x109 M-1s-1 and 1.2x109 M-1s-1, respectively).10Taking into account the rate constants and the lifetimes values of the involved species (1Ptr* (7.8ns), 3Ptr* (~6 µs), dGMP(-H)? (>100 µs)), at low concentration of RSV, the antioxidant reactssignificantly only with dGMP(-H)?, recovering the nucleotide and preventing its further oxidation.The results presented in the current study clearly demonstrate that RSV is efficient in the protectionof dGMP from one-electron oxidation.References:1- P. Langcake and R. J. Pryce, Phytochemistry, 1977, 16, 11932- Md. M. Hasan and H. Bae, Molecules, 2017, 22, 293- D. Delmas, A. Lancon, D. Colin, B. Jannin and N. Latruffe, Curr. Drug Targets, 2006, 7, 4234- V. Vingtdeux, et al., BMC Neuroscience, 2008, 9(Suppl 2):S65- S. Shigematsu, et al., Free Rad. Biol. Med., 2003, 34, 8106- A. Carrizzo, et al., Food Chem. Toxicol.,2013, 61, 2157- G. Petroselli, et al., J. Am. Chem. Soc., 2008, 130, 30018- M. P. Serrano, et al., New J. Chem., 2017, 41, 72739- J. Cadet, T. Douki and J.-L. Ravanat, Acc. Chem. Res., 2008, 41, 107510- J. R. Neyra Recky, Phys.Chem.Chem.Phys., 2019, 21, 16190