The molecule is a phenolate anion that is the conjugate base of protoaphin aglucone, obtained by deprotonation of the phenolic hydroxy group at position 7'; major species at pH 7.3. It is a conjugate base of a protoaphin aglucone.
(1R,3R,4S)-4,7,9-trihydroxy-1,3-dimethyl-5-[(1R,3R,4S)-4,7,9-trihydroxy-1,3-dimethyl-5,10-dioxo-3,4-dihydro-1H-benzo[g]isochromen-6-yl]-3,4-dihydro-1H-benzo[g]isochromen-10-olate