Quinoline alkaloids, important class of N-based heterocyclic aromatic compounds, have attracted tremendous attention from researchers worldwide, because of their wide-ranging biological activities and their varied applications. In the present work, the cytotoxic activities of dubamine and its 15 derivatives against HBL-100 and CCRF-СЕМ cancer cells and healthy blood mononuclear cells were studied. Among the tested dubamine derivatives, four compounds showed cytotoxic activity. The LD50 values of the substances was determined.