Methoxy- and acetoxy-8-oxoberbines--synthesis, antitumor activity, and interaction with DNA

Most of the methoxy-8H-dibenzo[a,g]isoquinolin-8-ones 3a-h and their acetoxy derivatives 6a-e were synthesized by condensation of 1-oxo-1,2,3,4-tetrahydroisoquinolines 4a-c and homophthalic acid anhydrides 5a and b, ether cleavage and acetylation. These protoberberinones were tested for cytostatic activity in vitro using MDA-MB-231 mammary tumor cells and for interaction with native calf thymus DNA. Tetramethoxy-8-oxoberbine 3f shows an inhibition of cell proliferation of 87% at a concentration of 10(-5) mole; its cytostatic effect does not depend on intercalation into DNA.