Antitumor agents 201.1 Cytotoxicity of harmine and β-carboline analogs

Twenty-six β-carbolines were evaluated for in vitro cytotoxicity in a human tumor cell line panel. Harmine (3) showed significant activity against several cell lines including three drug-resistant KB sublines with various resistance mechanisms. α-(4-Nitrobenzylidine) harmine (16) had a broad cytotoxicity spectrum (ED50 values from 0.3–1.2 μg/mL against 1A9, KB, SaOS-2, A549, SK-MEL-2, U-87-MG, and MCF-7 cells).