From marine molecules to the ideal sunscreen: what do the photophysicochemical studies tell?

CHURIO, MARIA SANDRA

Villa Carlos Paz

Encuentro; XIII Encuentro Latinoamericano de Fotoquímica y Fotobiología; 2017

It is well recognized that skin cancer can be prevented by reducing intentional exposure to UV radiation and improving photoprotection strategies. Topical application of sunscreens is the most widespread protective practice. Sunblock lotions typically contain a mixture of different types of organic and inorganic UV filters to ensure effective protection throughout the UVA and UVB spectra. However most commercial options have limited efficiency, they are not stable, or produce harmful reactive intermediates during energy dissipation pathways and thus pose risks to the environment and human health [1]. Hence, a novel kind of shields against sun rays based on natural sunscreens is emerging, that could protect not only people, but also textiles and outdoor materials [2]. Marine metabolites such as mycosporine-like amino acids (MAAs) have attracted great interes in relation to their photoprotective potential. High photostability in aqueous solution and efficient dissipation of the absorbed radiation energy as heat have been verified for MAAs isolated from algae. On the other hand, structurally and biosynthetically related to MAAs, there is gadusol, a metabolite that can be extracted from fishery debris. In addition to the intense absorbance in the UVB and the high photostability in water, gadusol efficiently deactivates radicals and electronicallyexcited species (photosensitizers, singlet oxygen) and exhibits redox properties similar to those of ascorbic acid [3].Appropriate solubilization and vehiculization of the active molecules is expected to be required in any innovative development based on these natural resources. This usually may convolve microheterogeneous systems where still the problematic of the safety of complex ingredien mixtures remains and the risks of phototoxic responses should be evaluated [2,4]. Thus, detailed descriptions of the physicochemical, photophysical and photochemical properties of MAAs and gadusol in more complex environments than aqueous solution are needed.We have carried out a series of photophysical and photochemical experimental studies in the last years with the goal of exploring the influence of different micellar and polymeric environments, as well as structural modifications on the MAAs shinorine and porphyra-334 and gadusol. This report will focus the effects on the protective ability against UV of the marine molecules and the factors that may contribute to improve the performance of novel sunscreen systems.Acknowledgments: Financial supports from Universidad Nacional de Mar del Plata (EXA 759/16- 15/E710) and CONICET (PIP 2014-0804) are greatly acknowledged.[1] C. Stiefel and W. Schwack, Int. J. Cosmet. Sci. 2014, 1.[2] K. Morabito, N. C. Shapley, K. G. Steeley, A. Tripathi, Int. J. Cosmet. Sci. 2011, 33, 385; S.C.M. Fernandes, A. Alonso-Varona, T. Palomares, V. Zubillaga, J. Labidi and V. Bulone, Appl. Mater. Interfaces, 2015, 7, 16558.[3] R. Losantos, D. Sampedro Ruiz, M. S. Churio, Pure Appl. Chem. 2015, 87, 979.[4] H. Nishida, M. Hirota,Y. Seto, G. Suzuki, M. Kato, M. Kitagaki, M. Sugiyama, H. Kouzuki and S. Onoue, Regul. Toxicol. Pharmacol. 2015, 72, 578