Observation of chemical change of mycosporine-like amino acids (MAAs) by UVA exposure

Abstract

Mycosporine-like amino acids (MAAs) have been posited to play a significant role in the UV protection, antioxidant activity and osmotic function in marine environment. Currently, about 20 different MAAs synthesized by cyanobacteria, fungi and eukaryotic micro- and macroalgae have been identified in aquatic environments. All MAAs have their own maximum absorption wavelength and it might be photodegraded if it is absorbing UV light above their maximum wavelength. Hence, numerous studies in connection with these chemical properties of MAAs have been conducted. In this study shinorine and porphyra-334 extracted from red algae Gloiopeltis furcata were used and it was also produced by phytoplankton Phaeocystis pouchetii and Porosira glacialis, which are the dominant species in Polar Regions. Both MAAs have shown the decrease of absorbance by ultraviolet and solar radiation, which mean that quantitative changes of shinorine and porphyra-334 may result in qualitative change. Also, in order to investigate for the effect of temperature, dark controls were compared and it retained at least 88 and 96% of the initial concentration, respectively. Therefore we concluded that temperature effects to degradation of MAAs were negligible. However the isolation and identification of MAAs such as shinorine and porphyra-334, two highly polar MAAs, still remain a critical challenge due to their extremely low concentration and weak sensitivity to ionization.