... Several species absorb strongly inthe UV -B range [1,2,4]. Lichens and their metabolites havebeen demonstrated to possess numerous biological activit-ies, including: antiviral, antibacterial, antitumor, ... and can beconsidered to be Schiff bases (enamino ketones), whichpossess a common cyclohexenone ring system linked by anaminoacidoranamino-alcohol[11].Incontrast,MAAsareUV absorbing metabolites ... commercialsunscreens by having a great potential to protect fromUV -B radiation. Collemin A is a new mycosporine, whichincorporates a novel pyrrolidine ring. The UV -B absorb-ance ability of this...