Synthesis and Antitumor activity of Cysteinyl-3,4-dihydroxyphenylalanines and Related Compounds

Article abstract of DOI:10.1021/jm00138a006

The natural catecholic amino acid 5-S-cysteinyl-3,4-dihydroxyphenylalanine (1) was selectively toxic to a variety of human tumor cell lines in culture and exhibited antitumor activity against L1210 leukemia and B-16 melanoma in mice at doses which were not toxic to the host.Structural analogues of 5-S-cysteinyl-3,4-dihydroxyphenylalanine, including several new compounds, were synthesized and tested for growth inhibition of cultured cells of human neuroblastoma YT-nu and Chinese hamster fibroblast Don-6.Some were also examined for antitumor activity against L1210 and B-16 in vivo. 4-S-Cysteinylcatechols and 2- and 4-S-cysteinylphenols, which cannot be prepared by conventional methods, were synthesized by the reaction of catechols and phenols with cystine in boiling aqueous HBr. 5-S-Cysteinyl and 2-S-cysteinyl-3,4-dihydroxyphenylalanine (1 and 2), L-3,4-dihydroxyphenylalanine (L-Dopa), and 2- and 4-S-cysteinylphenol (14 and 15) were toxic to the YT-nu cell line only, while 4-S-cysteinylcatechol (6), 3-S-cysteinyl-5-methylcatechol (8), 5-S-cysteaminyldopamine (9), and 4-methylcatechol were strongly toxic to both cell lines.Compounds 1 (1000 mg/kg), 6 (500 mg/kg), and 8 (400 mg/kg) increased the life span of L1210-bearing mice by 50, 50, and 43percent, respectively, and compounds 1 and 8 were marginally effective against B-16 melanoma as well.Compound 9 was too toxic to show any activity.There was good correlation between the cytotoxicity and the in vivo activity.