Studies On Diterpenes From The Seeds Of Croton Tiglium L. And Their Preliminary Evalution Of Antitumor Activity

This dissertation focused on the systematic investigation of the characteristic diterpens from Croton tiglium L., belonging to the genus Croton L. of the Euphorbiaceae family, through the technological methods common in modern natural products chemistry.From an acetone extract of the seeds of Croton tiglium L., a total of20phorbol esters (10new and10known) were isolated through column chromatrographies over silica gel, Sephadex LH-20and MCI, preparative TLC, preparative HPLC, etc. Through extensive analyses of the spectroscopic data including IR,1H-NMR,13C-NMR, HMBC, HSQC, ROESY, LR-ESI-MS and HR-ESI-MS spectrum, their structures were identified as7-Keto-12-O-tiglylphorbol-13-acetate (1),7-Keto-phorbol-12-tiglate (2),7-Keto-phorbol-12-(2-methyl)butyrate (3),7-Keto-phorbol-13-acetate (4),7-Keto-phorbol-13-decanoate (5),20-Formyl-phorbol-12-tiglate (6),20-Formyl-phorbol-13-dodecanoate (7),20-Formyl-phorbol-13-decanoate (8), Phorbol-13-dodecanoate (9), Phorbol-12-isobutyrate (10),12-O-Tiglylphorbol-13-acetate (11),12-O-(2-Methy l)-butyrylphorbol-13-acetate (12),12-O-Tiglylphorbol-13-isobutyrate (13), Phorbol-12-tigliate (14), Phorbol-12-(2-methyl)butyrate (15), Phorbol-12-tetradecanoate (16), Phorbol-13-acetate (17), Phorbol-13-decanoate (18),4-Deoxy-4a-phorbol-13-acetate (19), and4-Deoxy-4a-phorbol-12-tigliate (20). The structures of the new compounds1-10and the known ones11-20were shown as following.The isolates1,4,9,11,12,13,14,16,17,18, and19, together with the petroleum ether extract (BD-PE) and the acetone extract (BD-A) of the seeds, were applied for the preliminary evaluation of their inhibitory activities against human tumor cell line HL-60and lung carcinoma A549by MTT and SRB assaies, respectively. The results were shown as following:Compounds12and13showed strong inhibition activities against HL-60cells with IC50values below0.01μM while compounds11and18exhibited cytotoxicity against HL-60cells with IC50values in the range of0.01to0.1μM.Compound13showed strong inhibition activity against A-549cells with IC50value below0.01μM while comounds11and12exhibited cytotoxicity against A-549cells with IC50values ranging from0.01to0.1μM.In summary, through a systematic investigation on the chemical constitutes of the seeds of Croton tiglium L.,20characteristic phorbol esters including10new diterpens were isolated and structurally elucidated. The preliminary evalution showed that some isolates, the PE extract and the actone extract exhibited inhibitory activities against human tumor cell line HL-60and lung carcinoma A549. Our finding enlarged the knowledge of the chemical base of this herb and provided more scientific evidence to depict its medicinal usage research.