Structural requirements for tumor inhibitory activity among benzylisoquinoline alkaloids and related synthetic compounds

Article abstract of DOI:10.1021/jm00266a010

The results of a study directed toward determination of the structural requirements for tumor inhibitory activity among benzylisoquinoline alkaloids and related synthetic compounds are reported. Monomeric benzylisoquinolines and aporphines appear to have no inhibitory activity against the W 256 tumor system. In contrast, significant inhibitory activity is manifested by a wide range of bis(benzylisoquinoline) derivatives. The comparable activity of dl O methyldauricine and of bis(tetrahydroisoquinoline) with those of tetrandrine and thalidasine indicates that a macrocyclic ring is not required. Methylation of the nitrogen atoms does not appear to be necessary, for bis(benzyldihydroisoquinoline), bis(benzyltetrahydroisoquinolone), and bis(benzyl 3,4 dihydroisoquinoline) each show inhibitory activity. The significant activity of bis(benzyldihydroisoquinoline) and bis(benzyl 3,4 dihydroisoquinoline) indicates the apparent absence of stereospecficity requirements for biological activity in the series. One possible rationalization, that bis(benzylisoquinolines) may exert their tumor inhibitory activity by a mechanism involving initial metabolic dehydrogenation to bis(dihydroisoquinolinium) derivatives, is rendered unlikely by the observed inactivity of dimethiodide and the significant activity of bis(benzyltetrahydroisoquinoline).