Elucidation of Coloring Molecule Using a Simple Identification Method with a Color Reaction for <i>Omphalotus japonicus</i>

For Omphalotus japonicus, the coloring molecule was found and characterized using a simple method of identification with a color reaction. The compound that chang color under basic conditions was isolated from a methanolic extract of O. japonicus by liquid-liquid extraction. That compound was identified as thelephoric acid by various spectrum analyses. Color reaction by a beam reagent (5 w/v% potassium hydroxide ethanolic solution) and UV-Vis absorption of an ethanolic solution of thelephoric acid coincided with those of an ethanolic extract of O. japonicus. We conducted LC-MS/MS analyses of all four mushroom species (O. japonicus, Sarcomyxa serotina, Pleurotus ostreatus, and Lentinula edodes). Results demonstrated that thelephoric acid was detected only in O. japonicus. These findings indicate thelephoric acid as a coloring molecule for the identification method described above. This method is useful for distinguishing O. japonicus among other edible mushrooms having similar appearance.