2H-1-benzopyran-2-one, 4-(3,4-dihydroxyphenyl)-7-hydroxy-5-methoxy- 4-(3,4-dihydroxyphenyl)-7-hydroxy-5-methoxy-2H-chromen-2-one InChI=1/C16H12O6/c1-21-13-5-9(17)6-14-16(13)10(7-15(20)22-14)8-2-3-11(18)12(19)4-8/h2-7,17-19H,1H