Germacrone Dominates the Leaf Oil of Siparuna Grandiflora from Monteverde, Costa Rica

The leaf oil of Siparuna grandiflora (Monimiaceae) has been obtained by hydrodistillation and analyzed by GC-MS. The major components were germacrone (66.9%), germacrene B (8.2%), δ-cadinene (2.5%), trans-β-elemenone (2.2%), and β-elemene (2.1%). The leaf oil exhibited notable in-vitro cytotoxic activity on MCF-7 cells, brine shrimp lethality, and limited antimicrobial activity. DFT calculations (B3LYP/6-31G*) indicate that germacrone is slightly more stable than its Cope rearrangement product trans-β-elemenone.