Mycosporine-like amino acids (MAAs) are natural ultraviolet (UV)-
absorbing compounds that are attracting attention in the industrial field including
cosmetics and pharmaceuticals. This book provides a wide range of descriptions of
MAAs, from fundamentals to applications. In order to discuss the properties of MAAs,
an understanding of their chemical structures would be required. The purpose of this
chapter is to understand the basic molecular structure of MAAs. In general, MAAs
have structures in which amino acids are bound to the core structures of cyclohexenone
or cyclohexenimine. In addition to the basic structure, the resonance hybrid structures
of MAAs are also described here. Delocalization of electrons is considered to affect the
stability and the absorption maximum wavelength of MAA molecules. We will also
discuss the environmental factors that can affect the structure of MAAs. Finally,
databases of molecular structure information of MAAs will be described.
Keywords: Cyclohexenimine, Cyclohexenone, Environmental factors, Maximum absorption wavelength, Molar absorption coefficient, Molecular structure, Mycosporine-like amino acid, Resonance hybrid structure, Ultraviolet.
