Thesis (M.Sc.)--Chulalongkorn University, 2000

In the course of the investigation for chemical constituents of the stem bark of Croton roxburghii N.P.Balakr., two new clerodane-type diterpenoids, 3[alpha], 4[beta]-dihydroxy-5[alpha], 10[beta]-trans-17[alpha], 20[alpha]-cleroda-13 (14)-en-15, 16-olide and 11-acetoxy-3[alpha], 4[beta]-dihydroxy-5[alpha], 10[beta]-trans-17[alpha], 20[alpha]-cleroda-13 (14)-en-15, 16-olide have been isolated from crude ethyl acetate extract. The structures of these compounds were established by analysis of their spectroscopic data (UV, IR, MS, 1-D NMR, 2-D NMR, and X-ray diffraction analysis) as well as comparision with previously reported values. Each compound was tested for cytotoxicity against various human tumor cell lines: BT 474 (breast cancer), HEP-G2 (hepatoma), SW 620 (colon cancer), CHAGO (lung cancer), and KATO-3 (gastric cancer). Both compounds showed no cytotoxic activity against all tested cancer cell lines.