Electronic structure and cytotoxic activity of "half-mustard type" phenothiazines by MM3 and PM3 methods

Among 54 cancer cell lines, colon-cancer cells were the most sensitive to s ix "half-mustard type" phenothiazines [7-12], followed by leukemia, melanom a, prostate-, CNS-, breast-, lung-, renal and ovarian cancer cells. The dis tribution of electrostatic potential (ESP) of "half-mustard type" phenothia zines [7-12] suggests that the ESP surface of urea site is important for th e interaction between "half-mustard type" phenothiazines [7-12] and target cancer cell structures (or DNA base sequence). Actually, the urea site of " half-mustard type" phenothiazines displayed extensive variability in the en ergy of lone pair orbital and net atomic charges of N1, O and N3 atoms.