Development of Novel Fluorophores Based on Fluorescent Natural Products

Fluorescent molecules have been widely utilized in scientific researches, medical uses a industrial purposes. To develop fluorophores with useful and unpredictable functions, our group have focused on natural products, and identified fluorescent natural products, Amarastelline A and Nigakinone. For the evaluation of those functions as a fluorophore and the development novel fluorescent sensors, we synthesized various derivatives of these common structures, canthin-5,6-dione and 1,5-naphthyridin-2(1H)-one. Among them, novel polarity-sensitive fluorophore, which showed the shift of fluorescence maximum wavelength by the change of solvent polarity, could be obtained. To apply this function to the study of biomolecule interaction, C5 peptide, which could interact calmodulin, labelled with this fluorophore, was synthesized, and its interaction with calmodulin could be detected by the ratio the fluorescence intensities at two fluorescent maximum wavelengths. Our findings indicated the usefulness of natural products for the development of novel fluorescent molecules, as well as the versatilities of canthin-5,6-dione and 1,5-naphthyridin-2(1H)-one.