Showing structure for [13,17,18,21-tetrahydroxy-7-(hydroxymethyl)-2,10,14-trioxo-5-(3,4,5-trihydroxybenzoyloxy)-3,6,9,15-tetraoxatetracyclo[10.7.1.1⁴,⁸.0¹⁶,²⁰]henicosa-1(19),16(20),17-trien-11-yl]acetic acid