Crokonoids A-C, A Highly Rearranged and Dual-Bridged Spiro Diterpenoid and Two Other Diterpenoids from Croton kongensis

摘要

Crokonoid A (1), a highly rearranged diterpenoid featuring a dual-bridged tricyclo[4.4.1.1(1,4)]dodecane-2,11-dione ring system and its two possible ent-kaurene diterpenoid precursors (2 and 3), was isolated and structurally characterized by solid data from Croton kongensis. Compound 1 exhibited significant cytotoxicity against HL-60 and A-549 cell lines with IC50 values of 1.24 +/- 0.56 and 1.92 +/- 0.60 mu M, respectively.