Naphthazarin derivatives (VII): antitumor action against ICR mice bearing ascitic S-180 cells

Cytotoxicity of Synthesized 1,4-Naphthoquinone Oxime Derivatives on Selected Human Cancer Cell Lines

In an effort to develop potent and selective antitumor agents, a series of 1,4-naphthoquinone oxime derivatives were designed and synthesized. The cytotoxicity of these compounds were evaluated against five human cancer cell lines (colorectal cancer cell: HCT-15, breast cancer cell: MDA-MB-231, liver cancer cell: BEL-7402, colorectal cancer cell: HCT-116 and ovarian cancer cell: A2780) in vitro. Among them, compound 14 was found to be the most potent cytotoxic compound against three cell lines (MDA-MB-231, BEL-7402 and A2780) with IC₅₀ values of 0.66±0.05, 5.11±0.12 and 8.26±0.22 µM, respectively. Additionally, the length of the side chains and the position of the substituent may also affect the cytotoxic activity of the naphthoquinone oxime derivatives. In general, compound 14 effectively inhibited breast cancer cell proliferation and may become a promising anticancer agent.

A Convenient and Efficient Synthesis of 2-Acetyl-5,8-Dimethoxy-1,4-Naphthoquinone

A convenient and efficient synthesis of the important naphthazarin derivative 2-acetyl-5,8-dimethoxy-1,4-naphthoquinone is introduced in this paper. The key steps of the synthetic strategy involve the selective demethylation of 2-acetyl-1,4,5,8-tetramethoxynaphthalene with anhydrous aluminum chloride and subsequent oxidation of the demethylated product by cerium ammonium (IV) nitrate. Compared with the reported routes, the overall yield is much higher and the work-up of each step is simpler. Moreover, the reaction conditions are milder and all the reactions involved in the method are more suitable for large-scale preparations.

Synthesis and evaluation of antitumor activity of novel 1,4-Naphthoquinone derivatives (IV)

1,4-Naphthoquinones are widely distributed in nature and many clinically important antitumor drugs containing a quinone moiety, such as anthracyclines, mitoxantrones and saintopin, show excellent anticancer activity. In this study, 2- or 6-substituted 5,8-dimethoxy-1,4-naphthoquinone (DMNQ) and 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) derivatives were synthesized, and their cytotoxic activity against L1210 and P388 cancer cells was examined. Their antitumor activity was also assessed in mice bearing S-180 cells in the peritoneal cavity. In comparison with the DMNQ derivatives, the DHNQ derivatives exhibited more potent bioactivities than the DMNQ derivatives against both L1210 and P388 cells in vitro and S-180 cells in vivo. The ED50 values of the DHNQ derivatives against P388 cells were in the range of 0.18-1.81 microg/mL whereas those of the DMNQ derivatives were in the range of 0.26-40.41 microg/mL. The T/C (%) values of the DHNQ derivatives, 8, 17, 18, 19, and 20, were found to be comparable to or even better than that of adriamycin. It was also observed that the 2-substituted derivatives (8, 19, 20) showed better antitumor activity than the 6-substituted derivatives (7, 17, 18) in the mice bearing S-180 cells in the peritoneal cavity.

Synthesis and evaluation of antitumor activity of 2- and 6-[(1,3-benzothiazol-2-yl)aminomethyl]-5,8-dimethoxy-1,4-naphthoquinone derivatives

2- or 6-substituted BZT-N derivatives were synthesized, and their cytotoxic activity against cancer L1210 and SNU-1 cells was examined. The antitumor action was also assessed in mice bearing S-180 cells in peritoneal cavity. In a comparison, it was found that 6-substituted BZT-N derivatives exhibited higher potencies in both bioactivities than 2-substituted BZT-N derivatives against L1210 cells in in vitro and S-180 in vitro tests exception of compound 36. Interestingly, it was observed that 2-substituted compound 36, which has methyl group at R1 position, exhibited a better antitumor activity than 6-substituted compounds against L1210 and SNU-1 in vitro. The ED50 value of 2-substituted compound 36 against L1210 was found to be comparable to the ED50 value of adriamycin and was even better against the solid cancer cell line SNU-1. It was also observed that 2-substituted compound 36 showed better antitumor activity in mice bearing S-180 cells in the peritoneal cavity. The T/C (%) value of 2-substituted compound 36 was similar to that of adriamycin. Quantitative structure-activity relationship (QSAR) tests reveal that the experimental ED50 values against SNU-1 closely correlate with both the calculated HOMO energies (E(HOMO)) and the measured 1H-NMR chemical shift of 3-H (deltaH). The results suggests that a compound having higher E(HOMO) and deltaH values usually should have a lower ED50 (SNU-1) value.