Cytotoxicity of chemical constituents of the stem barks of Croton oblongifolius Roxb. from Muang, Prachuap Khan Province

Abstract

The stem barks of Croton oblongifolius Roxb. were extracted with hexane, ethyl acetate and methanol, respectively. The extracts were separated by column chromatography on silica gel. Six compounds were isolated and identified, namely, Trachyloban-19-oic-acid (1) (trachylobane diterpenoid), Poilaneic acid (2) (cembrane diterpenoid), 12(E),14-labdadiene-7,8-diol (4), 6-acetoxy-12(E),14-labdadiene-7,8-diol (5), 12(E),14-labdadiene-6,7,8-triol (6) (labdane diteipenoid) and a mixed steroid of Stigmasterol and β -sitosterol(3). Moreover, this is the first report of compound 1, 5 and 6 from this plant. Compound 4a was obtained from the acetylation of compound 4, which was assigned as 7-acetoxy-12,14-labdadiene-8-ol. Their physical properties and spectroscopic data identified the structures of the isolate compounds. The compounds were tested for cytotoxicity against cancer cell lines: Hep-G2 (hepatoma), SW 620 (colon), Chago (lung), Kato-3 (gastric) and BT 474 (breast). Compound 4 and compound 6 showed strong activity against all cancer cell lines. Compound 5 and compound 4a showed moderate activity against Hep-G2, SW 620, Chago and Kato-3. However, compound 1 and compound 2 showed only weak activity against Hep-G2 and SW 620.