Ultraviolet photoprotective compounds from cyanobacteria in biomedical applications

Cyanobacteria are among the few groups of microorganisms for which a full array of evolutionary adaptations to photoprotection have been studied. Among these, the synthesis of dedicated secondary metabolites to function as sunscreens and antioxidants has high potential for application in the biomedical industry. This chapter reviews these photoprotective compounds in the light of their biology and compares them with current, synthetic alternatives, so as to establish their potential that includes industrial practices and standards. Scytonemin is an attractive natural product that has antiproliferative properties. The broad spectrum ultraviolet radiation (UVR) filter Tinosorb can increase the ultraviolet protection factor (UPF) of cotton T-shirts to 30, and remains stable through multiple washings. An approach to overcoming obstacles to mass sunscreen production would be to exert transcriptional control over sunscreen biosynthesis, regardless of the UVR input or the amount of sunscreen already accumulated.