Background: 9-anilinoacridines are acting as DNA-intercalating agents which plays an important
role as antitumor drugs, due to their anti-proliferative properties. Some anticancer agents contain 9-
anilinoacridines such as amsacrine (m-AMSA), and nitracrine (Ledakrine) have been already developed.
Methods: In this study, novel 9-anilinoacridines substituted with thiazines 4a-r were designed, synthesized,
characterized by physical and spectral data and their cytotoxic activities against DLA cell lines were evaluated.
Results: Among those compounds, 4b, c, e, g, i, j, k, m, o, p, q, r exhibited significant short term in vitro cytotoxic
activity against Daltons lymphoma ascites (DLA) cells with CTC50 value of 0.18 to 0.31μM. The compounds
4b, c, e, g, i, j, k, m, o, p, q, r are also exhibited significant long term in vitro anti-tumour activity
against human tumor cell lines, HEp-2 (laryngeal epithelial carcinoma) by Sulforhodamine B assay with CTC50
value of 0.20 to 0.39μM. The compounds 4b, i, j exhibited significant in vivo antitumor activity with % Increase
in Life Span (ILS) 48-82%.
Conclusion: Results obtained in this study clearly demonstrated that many of the thiazine substituted 9-
anilinoacridines exert interesting anti-tumour activity. The compounds 4b, i, j have significant anti-tumour
activity and useful drugs after further refinement. The above derivatives will encourage to design future antitumor
agents with high therapeutic potentials.