Two Terpenoid Derivatives with Different 3/5/6/6/ 5‐Fused Pentacyclic Skeletons fromHedyosmum orientale

Comprehensive Summary Chemical investigation ofHedyosmum orientaleled to the identification of two terpenoid derivatives, dyosmunoids A and B (1and2) featuring two different 3/5/6/6/5‐fused pentacyclic ring systems, respectively. Compound1is the second natural product of this C25terpenoid compound class, and compound2is a rare dinor‐C25terpenoid with a peroxide bridge. Their structural elucidation was achieved by the comprehensive analysis of spectroscopic data, single‐crystal X‐ray diffraction, and ECD calculation. Putative biosynthetic pathways for compounds1and2are proposed. Compound2exhibited strong antimalarial activity with an IC50value of 0.42 μmol·L–1.