Photochemical & Photobiological Sciences
Communication
coupled to a Czerny–Turner monochromator, under argon, for 30 min. The pro-
gress of the reaction was followed by an ACQUITY UPLC System (Waters Corp.)
connected to a Waters ACQUITY™ XevoQToF Spectrometer via an electrospray
ionization (ESI) interface. The separation was carried out on a C18 column
(50 mm × 2.1 mm i.d., 1.7 μm). The analysis was achieved with gradient elution
using acetonitrile and water as the mobile phase. The ESI source was operated in
+
positive ionization mode with the capillary voltage at 3.0 kV generating [M + H]
ions.
Scheme 1 Mechanism for the oxygen transfer process between donor and
1
2
3
4
5
J. Cadet, S. Mouret, J.-L. Ravanat and T. Douki, Photo-
induced damage to cellular DNA: direct and photosensi-
tized reactions, Photochem. Photobiol., 2012, 88, 1048–1065.
G. P. Pfeifer and A. Besaratinia, UV wavelength-dependent
DNA damage and human non-melanoma and melanoma
skin cancer, Photochem. Photobiol. Sci., 2012, 11, 90–97.
J. Cadet, E. Sage and T. Douki, Ultraviolet radiation-
mediated damage to cellular DNA, Mutat. Res., 2005, 571,
acceptor moieties.
detected by UPLC-MS/MS. Their exact mass was 644.3691 and
6
44.3682 corresponding to the molecular formula C H N O
38 50 3 6
+
(MH ); both of them matched with the incorporation of one
oxygen atom to 1. Control experiments confirmed that the
presence of both 1 and 2 was required for the photochemical
formation of these products, which were not detected in the
dark.
3
–17.
E. Sage, P.-M. Girard and S. Francesconi, Unravelling UVA-
induced mutagenesis, Photochem. Photobiol. Sci., 2012, 11,
To disclose the substructure of 1 responsible for acceptance
3
74–80.
of O( P), several model compounds were used to analyze their
A. Banyasz, I. Vayá, P. Changenet-Barret, T. Gustavsson,
T. Douki and D. Markovitsi, Base pairing enhances fluore-
scence and favors cyclobutane dimer formation induced
upon absorption of UVA radiation by DNA, J. Am. Chem.
Soc., 2011, 133, 5163–5165.
S. Mouret, C. Baudouin, M. Charveron, A. Favier, J. Cadet
and T. Douki, Cyclobutane pyrimidine dimers are predomi-
nant DNA lesions in whole human skin exposed to UVA
radiation, Proc. Natl. Acad. Sci. U. S. A., 2006, 103,
behavior under irradiation in the presence of 2. The selected
fragments were related to the substituents of the heterocyclic
core (methoxybenzene and m-methoxyphenol) as well as to
triazine itself (parent compound and trimethoxy-substituted).
The only oxygenated photoproduct was found for methoxy-
benzene and was identified as o-methoxyphenol.
6
7
8
9
Overall, these findings support photochemical oxygen trans-
fer from a N-oxide to Tinosorb S, confirming the feasibility of
this solar filter to act as an oxygen acceptor. This occurs by
N-oxide photocleavage with generation of atomic oxygen, fol-
lowed by reaction of this species with the solar filter as an
acceptor (Scheme 1), rather than by direct oxygen transfer in the
13765–13770.
E. Venditti, F. Brugè, P. Astolfi, I. Kochevar and E. Damiani,
Nitroxides and a nitroxide-based UV filter have the
potential to photoprotect UVA-irradiated human skin fibro-
blasts against oxidative damage, J. Dermatol. Sci., 2011, 63,
19
excited state. Transient absorption spectroscopy, high-resolu-
tion mass spectrometry and steady-state photolysis with model
compounds strongly support the proposed mechanism.
55–61.
N. Bastien, J.-F. Millau, M. Rouabhia, R. J. H. Davies and
R. Drouin, The sunscreen agent 2-phenylbenzimidazole-
In summary, the triazine-containing UV-filter 1 may act as a
scavenger of ROS, specifically atomic oxygen. As inclusion of
5-sulfonic acid photosensitizes the formation of oxidized
antioxidants in sunscreen compositions is becoming
a
guanines in cellulo after UV-A or UV-B exposure, J. Invest.
Dermatol., 2010, 130, 2463–2471.
O. R. Wauchope, S. Shakya, N. Sawwan, J. F. Liebman and
A. Greer, Photocleavage of plasmid DNA by dibenzothio-
phene S-oxide under anaerobic conditions, J. Sulfur Chem.,
common strategy for preventing/reducing photo-oxidative skin
7
,20
damage,
the preliminary results presented here suggest
that 1 and related filters may play a dual role and can be
useful for improving the efficacy of skin care cosmetic formu-
lations against photo-carcinogenesis and photo-aging.
We thank the Spanish Government (Project CTQ2009-13699
and fellowship to N. D.-G.) for financial support.
2007, 28, 11–16.
10 J. F. Orrego, T. N. Truong and F. Mondragon, A linear
energy relationship between activation energy and absolute
3
hardness: a case study with the O( P) atom-addition reac-
tions to polyaromatic hydrocarbons, J. Phys. Chem. A, 2008,
Notes and references
112, 8205–8207.
1
1 M. Zhang, G. E. Ravilious, L. M. Hicks, J. M. Jez and
R. D. McCulla, Redox switching of adenosine-5′-phospho-
sulfate kinase with photoactivatable atomic oxygen precur-
sors, J. Am. Chem. Soc., 2012, 134, 16979–16982.
†
Laser flash photolysis experiments were carried out using a pulsed Nd:YAG
laser for excitation at 266 nm (single pulse duration ≤10 ns and energy of
1
−
5
−5
0 mJ). Acetonitrile solutions of 2 (4.3 × 10 M) and 3 (2.9 × 10 M) were irra-
diated in the presence of several 1 : 2 or 1 : 3 ratios (0.1–1) under anaerobic
atmosphere. All the compounds were irradiated separately as controls.
For steady-state photolysis, 1 × 10−4 M acetonitrile solutions of 2 in the pres-
12 B. Herzog, M. Wehrle and K. Quass, Photostability of UV
absorber systems in sunscreens, Photochem. Photobiol.,
2009, 85, 869–878.
‡
ence of 1 (1 : 10) or in the presence of model compounds (1 : 1) were subjected to
monochromatic irradiation (266 nm) using a 100 W xenon lamp from PTI,
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