Diterpenoids from the Roots of Croton oblongifolius

Two new clerodane diterpenes, methyl 15,16-epoxy-3,13(16),14- ENT-clerodatrien-18,19-olide-17-carboxylate ( 1) and dimethyl 15,16-epoxy-12-oxo-3,13(16),14- ENT-clerodatriene-17,18-dicarboxylate ( 2), together with seven known compounds ( 3 - 9), were isolated from the roots of Croton oblongifolius. The isolated compounds showed only mild cytotoxic activity against HuCCA-1, KB, HeLa, MDA-MB231, and T47D cell lines with IC (50) values ranging from 10 to 50 microg/mL.