1H-2-benzopyran-1-one, 3-[(E)-2-(3,4-dihydroxyphenyl)ethenyl]-6,8-dihydroxy- 3-[(E)-2-(3,4-dihydroxyphenyl)vinyl]-6,8-dihydroxy-1H-isochromen-1-one InChI=1/C17H12O6/c18-11-6-10-7-12(23-17(22)16(10)15(21)8-11)3-1-9-2-4-13(19)14(20)5-9/h1-8,18-21H/b3-1