Antioxidant action of Resveratrol in the prevention of guanine photosensitized oxidation

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

Viña del Mar

Congreso; XIV Encuentro Latinoamericano de Fotoquimica y Fotobiologia; 2019

Universidad Andres Bello

Resveratrol (3,4´,5,-trihydroxystilbene, RSV) is a naturalpolyphenolic compound naturally present in a variety of plant species,especially in fruits and flowers such as grapevines, nuts, lilly flowers, andit is synthesized in response to stress situations such as infections or UVradiation.1,2 During the last years, the interest in RSV has increased due tothe evidences found of many beneficial properties against aging and for theprevention and/or treatment of various diseases such as cancer, Alzheimer andcardiac dysfunction3-6 It has beenreported that pterin (Ptr), is able to photosensitize the degradation of thepurine nucleotide 2?-deoxyguanosine 5?- monophosphate (dGMP) in aqueoussolution.7,8 In acidic conditions the main mechanism of this process is type Imechanism, and is initiated with an electron transfer from dGMP to tripletexcited state of Ptr (3Ptr*), where theguanine radical cation (dGMP?+) is formed(Scheme).9 This radicalundergoes fast deprotonation to form the neutral radical (dGMP(-H+)?), which as previously described by Cadet et al, is the origin ofoxidative damage on DNA molecules from one-electron oxidation by diversechemical or physical oxidizing agents, and in aqueous media suffersnucleophilic addition or deprotonation reactions yielding several products.10 Kinetic analysis (HPLC-UV, UPLC-MS) during steady-stateirradiation (λIRR = 365 nm))indicates that RSV protects dGMP from oxidation. By fluorescence and laserflash photolysis experiments (LP980, Edinburgh) the bimolecular quenching rateconstants of 1Ptr*, 3Ptr* and dGMP(-H)? with RSV weredetermined (1.1(±0.1)x1010s-1M-1, 4.94x109 M-1s-1 and 1.2x109 M-1s-1, respectively).10 Taking into account the rate constants and the lifetimes values ofthe involved species (1Ptr* (7.8 ns), 3Ptr* (~6 µs), dGMP(-H)? (>100 µs)), at low concentration of RSV, the antioxidant reactssignificantly only with dGMP(-H)?, recovering thenucleotide and preventing its further oxidation. The results presented in thecurrent study clearly demonstrate that RSV is efficient in the protection ofdGMP 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. DrugTargets, 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