1,2-bis(5-hydroxy-1H-indol-3-yl)ethane-1,2-dione 1,2-ethanedione, 1,2-bis(5-hydroxy-1H-indol-3-yl)- InChI=1/C18H12N2O4/c21-9-1-3-15-11(5-9)13(7-19-15)17(23)18(24)14-8-20-16-4-2-10(22)6-12(14)16/h1-8,19-22