Hemisynthetic Secofriedelane Triterpenes with Inhibitory Activity against the Growth of Human Tumor Cell Lines in Vitro
摘要:
Seco acids 7 and 9 and hydroxylated analogues 5 and 6 derived from friedelane triterpenes were synthesized stereoselectively in high yields. Compounds 5-9 were evaluated for their ability to inhibit in vitro the growth of three human tumor cell lines, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), and SF-268 (CNS cancer). Only compounds 7 and 9 were found to possess significant growth inhibitory effects, exhibiting GI(50) values that range from 24.6 to 32.8 muM and 10.9 to 17.6 muM, respectively.
Base-catalyzed autoxidation of a triterpene ketone, friedelin, in the presence of potassium t-butoxide gave four products, and their structures and formation mechanism were investigated. The common intermediate to these compounds was suggested to be 4-hydroperoxyfriedelan-3-one, not friedelane-2,3-dione. 3-Oxafriedel-1-ene-2-carboxylic acid was a dehydration product of the main product, 2-hydroxy-