Antitumor agents. Part 209: Pheophorbide-a derivatives as photo-Independent cytotoxic agents
摘要:
A methanotic crude extract of the plant Garuga pinnata Roxb. (Burseraceae) showed promising cytotoxic activity against a panel of human tumor cell lines in vitro. including KB and its drug-resistant sublines (Ferguson et al. Cancer Res. 1988, 48, 5956). Pheophorbide-a and-h methyl esters (3.4) were isolated as active principles with broad photo-dependent cytotoxic activities in the micromolar range. These findings prompted SAR studies of known and novel pheophorbide-a derivatives as photo-dependent and hoto-independent cytotoxic agents. The results showed that zinc-protoporphyrin IX (10). zinc 13(2)(R)-hydroxypheophorbide-a methyl ester (22), and zinc chlorin-e6 trimethyl ester (13) possessed photo-independent cytotoxic activity. Compounds 13 and 22 were the most active cytotoxic agents of the series (mean ED50 4.6 +/- 1.0 muM and 5.7 +/- 0.7 muM, respectively) against KB cells incubated in the dark. (C) 2002 Elsevier Science Ltd. All rights reserved.
Transesterification of the α-keto ester in methyl pheophorbide-a
作者:Satoshi Shinoda、Atsuhiro Osuka
DOI:10.1016/0040-4039(96)01075-1
日期:1996.7
Transesterification of the α-keto methylester in methyl pheophorbide-a proceeds smoothly under neutral conditions, allowing the preparation of a variety of models such as steroid-pheophorbide, pyromellitimide-pheophorbide, thymidine-pheophorbide, pheophorbide dimer, and porphyrin-pheophorbide.