Cytotoxicity to cancer cell lines of diterpenoid compounds from stem bark of Croton oblongifolius Roxb. from Chachoengsao Province

Abstract

Extraction of the stem barks of Croton oblongifolius Roxb. from Chachoengsao province with hexane and ethyl acetate gave a mixture of steroids and six compounds. The structures of these substances were established on the basis of physical properties and spectroscopic data. They were a mixture of stigmasterol, β-sitosterol and campesterol (5), two clerodane diterpenoids; (-)-hardwickiic acid (2) and (-)-20-benzyloxyhardwickiic acid (7) and four labdane diterpenoids; labda-7,12 (E),14-triene-17-oic acid (1), 2-acetoxy-labda-8(17),12(E),14-triene-3-ol (3), 3-acetoxy-labda-8(17),12(E),14-triene-2-ol (4) and labda-8(17),12(E),14-triene-2,3-diol (6). They were tested for their cytotoxicity against human tumor cell lines; Hep-G2 (hepatoma), SW 620 (colon), Chago (lung), Kato-3 (gastric) and BT 474 (breast). Compound 3 and 6 showed significant cytotoxicity against all cell lines. Compound 4 exhibited moderate cytotoxicity against Hep-G2 and Kato-3. Moreover, this is the first report of cytotoxicity test of (-)-hardwickiic acid (2).