Robust natural ultraviolet filters from marine ecosystems for the formulation of environmental friendlier bio-sunscreens.

Ultraviolet radiation (UVR) has detrimental effects on human health. It induces oxidative stress, deregulates signaling mechanisms, and produces DNA mutations, factors that ultimately can lead to the development of skin cancer. Therefore, reducing exposure to UVR is of major importance. Among available measures to diminish exposure is the use of sunscreens. However, recent studies indicate that several of the currently used filters have adverse effects on marine ecosystems and human health. This situation leads to the search for new photoprotective compounds that, apart from offering protection, are environmentally friendly. The answer may lie in the same marine ecosystems since molecules such as mycosporine-like amino acids (MAAs) and scytonemin can serve as the defense system of some marine organisms against UVR. This review will discuss the harmful effects of UVR and the mechanisms that microalgae have developed to cope with it. Then it will focus on the biological distribution, characteristics, extraction, and purification methods of MAAs and scytonemin molecules to finally assess its potential as new filters for sunscreen formulation.

Bioinspired biomolecules: Mycosporine-like amino acids and scytonemin from Lyngbya sp. with UV-protection potentialities.

Since the beginning of life on Earth, cyanobacteria have been exposed to natural ultraviolet-A radiation (UV-A, 315-400 nm) and ultraviolet-B radiation (UV-B, 280-315 nm), affecting their cells' biomolecules. These photoautotrophic organisms have needed to evolve to survive and thus, have developed different mechanisms against ultraviolet radiation. These mechanisms include UVR avoidance, DNA repair, and cell protection by producing photoprotective compounds like Scytonemin, carotenoids, and Mycosporine-like amino acids (MAAs). Lyngbya marine species are commercially important due to their secondary metabolites that show a range of biological activities including antibacterial, insecticidal, anticancer, antifungal, and enzyme inhibitor. The main topic in this review covers the Lyngbya sp., a cyanobacteria genus that presents photoprotection provided by the UV-absorbing/screening compounds such as MAAs and Scytonemin. These compounds have considerable potentialities to be used in the cosmeceutical, pharmaceutical, biotechnological and biomedical sectors and other related manufacturing industries with an additional value of environment friendly in nature. Scytonemin has UV protectant, anti-inflammatory, anti-proliferative, and antioxidant activity. MAAs act as sunscreens, provide additional protection as antioxidants, can be used as UV protectors, activators of cell proliferation, skin-care products, and even as photo-stabilizing additives in paints, plastics, and varnishes. The five MAAs identified so far in Lyngbya sp. are Asterina-330, M-312, Palythine, Porphyra-334, and Shinorine are capable of dissipating absorbed radiation as harmless heat without producing reactive oxygen species.