Showing structure for methyl 11,15,16-trihydroxy-9,13-dimethyl-3-[(3-methylbut-2-enoyl)oxy]-4,10-dioxo-5,18-dioxapentacyclo[12.5.0.0¹,⁶.0²,¹⁷.0⁸,¹³]nonadeca-8,11-diene-17-carboxylate