InChI=1S/C22H22O9/c1-31-18-11-14(3-7-16(18)25)5-9-20(28)22(30,21(29)12-23)19(27)8-4-13-2-6-15(24)17(26)10-13/h2-11,21,23-26,29-30H,12H2,1H3/b8-4+,9-5+