Fig. (5) Cleavage of supercoiled pBR322 plasmid (300 ng) by the investigated compounds (20 μM) in Tris-HCl (5 mM)/NaCl (50 mM) buffer (pH 7.2) for 1 h at 37°C. Lane 1: DNA (control 1); lane 2: DNA + 1% DMSO (control 2); lane 3: DNA + 1A; lane 4: DNA + 1B; lane 5: DNA + 2A; lane 6: DNA + 2B.