Corymbinols A and B: Bis-β-triketone Conjugates of Sesquiterpene and Chalcone from the Fruit of Corymbia citriodora.

Corymbinols A (1) and B (2a/2b), unprecedented bis-β-triketone-sesquiterpene and -chalcone hybrids, together with their biogenic precursors corymbinol C (3) and rhodomyrtosone E (4) were isolated from the untapped fruit of Corymbia citriodora. The absolute configurations of these compounds were determined by NMR spectroscopy, electronic circular dichroism (ECD) calculations, and X-ray crystallography. Compound 1 exhibited moderate inhibitory activity against cuproptosis in HepG2 cells by 31% at a nontoxic concentration of 20 μM.