Showing structure for 15,16-dihydroxy-4,5,5,9,10,10-hexamethyl-3,8,13-trioxapentacyclo[10.8.0.0²,⁶.0⁷,¹¹.0¹⁴,¹⁹]icosa-1,6,11,14,16,18-hexaen-20-one