Showing structure for 3,6-dihydroxy-4,6,7,15,17,18-hexamethyl-8,11,19-trioxapentacyclo[10.7.1.0²,¹⁰.0⁵,⁹.0¹⁶,²⁰]icosa-1(20),2,4,9,12,15-hexaen-14-one