Synthesis, antioxidant and antitumoral activities of 5'-arylchalcogeno-3-aminothymidine (ACAT) derivatives

Abstract

This article presents the preparation and in vitro biological activities of new 5'-arylchalcogeno-3-aminothymidine derivatives as antioxidants (inhibition of lipid peroxidation, scavenging of the free radical 2,2-diphenylpicrylhydrazyl and demonstration of a thiol peroxidase-like activity) as well as antitumoral agents against bladder carcinoma 5637. The chalcogeno-aminothymidines presented prominent activity in the tests for both biological properties, showing a direct relation with the chalcogenium atom.

Scheme 1. Synthesis and biological evaluation of the 5′-arylchalcogeno-3-aminothymidine derivatives.

Fig. 1. Synthesis of 5′-arylchalcogeno-3-aminothymidines 3a–m.

Fig. 2. Compound 3j (A) induces higher antiproliferative rates in 5637 cells than commercial AZT (B). Cell proliferation was investigated by the MTT assay. Data are expressed as means ± SEM from three independent experiments. The different uppercase letters (A and B) indicate significant differences between treatment times and the lowercase letters (a–c) indicate significant difference between treatment concentrations. Differences were considered significant at P < 0.05.

Fig. 3. Antiproliferative effect of 5′-arylchalcogeno-3-aminothymidines on 5637 cancer cells in 48 h of treatment. ACATs 3a (A), 3b (B), 3c (C), 3d (D), 3e (E), 3i (F), 3j (G), 3k (H), 3l (I), and 3m (J). Cell proliferation was investigated by the MTT assay. Data are expressed as means ± SEM from three independent experiments.

Fig. 4. Number of 5637 human bladder carcinoma cells in each phase of the cell cycle (Sub G0, G0/G1, S, and G2/M) after 24 hours of treatment with compound 3j. Results are expressed as mean ± SEM of the mean from three independent experiments. Data were analyzed by two-way ANOVA followed by Bonferroni test. ** ≠ G0/G1 control and * ≠ S control (p < 0.05).

Fig. 5. Effect of azidothymidine derivatives (200 μM) on the inhibition of lipid peroxidation induced by iron. Diphenyl diselenide ((PhSe)₂) and α-tocopherol (200 μM) were used as positive controls. a ≠ DMSO; b ≠ (PhSe)₂; and c ≠ α-tocopherol.

Fig. 6. Concentration dependent inhibition of lipid peroxidation by compound 3j, (PhSe)₂ and α-tocopherol. Results are expressed as mean ± S.E.M. of three determinations. * ≠ 0 μM. Data were analyzed by one-way ANOVA followed by Newman–Keuls test (p < 0.05).

Fig. 7. DPPH scavenging activity of azidothymidine derivative compounds (1 mM) after 90 min of incubation. a ≠ DMSO. Butylated hydroxytoluene (BHT, 0.5 mM) was used as a positive control.

Fig. 8. Concentration and time-dependent curves of compound 3j in the DPPH scavenging activity test. Results are expressed as mean ± S.E.M. of three determinations. * ≠ 0 minute. Data were analyzed by one-way ANOVA followed by Newman–Keuls test (p < 0.05).

Fig. 9. Thiol peroxidase-like activity of azidothymidine derivatives (450 μM). Diphenyl diselenide ((PhSe)₂) was used as a positive control. a ≠ DMSO. Results are expressed as mean ± SEM of three determinations. Data were analyzed by the student's t test.

Fig. 10. Concentration curve of compound 3j in the thiol peroxidase-like activity test. Diphenyl diselenide ((PhSe)₂) and ebselen were used as positive controls. * ≠ 0 μM. Results are expressed as mean ± SEM of three determinations. Data were analyzed by one-way ANOVA followed by the Newman–Keuls post hoc test (p < 0.05).

Fig. 11. Cell viability in human leukocytes after treatment with compound 3j. t-Butyl hydroperoxide (1 mM) was used as a positive control. Results are expressed as mean ± SEM of three determinations. * ≠ DMSO. Data were analyzed by one-way ANOVA followed by Newman–Keuls test (p < 0.0001).

Fig. 12. Survival rate after subcutaneous (s.c.) injection of 100 μmol kg^–1 of 3j. Data were analyzed using the log-rank (Mantel–Cox) test.

Fig. 13. Organ-to-body weight ratio of the brain (A), liver (B), kidney (C) and spleen (D) after treatments with 3j (100 μmol kg^–1) or DMSO (control group). Data were analyzed by the unpaired t test. There was no significant difference between the groups.

Fig. 14. (A) Effect of 3j (100 μmol kg^–1, s.c.) on the urea and (B) creatinine levels. Data were analyzed by the unpaired t test. There was no significant difference between the groups.

Fig. 15. (A) Effects of 3j (100 μmol kg^–1, s.c.) on ALT and (B) AST activity. Data were analyzed by the unpaired t test. There was no significant difference between the groups.