Thymoquinone Cytotoxicity in Dictyostelium

Dictyostelium AX4 (axenic) amoebae were grown at 22°C on a rotary shaker (180 rpm) in HL5 media containing 100 mg/mL of streptavidin and 100 units/mL penicillin. Initially, the IC50 for thymoquinone was determined by seeding amoebae at 5x 10⁴ cells/ml with 0.25, 0.5, 1, 2.5, 5.0, 7.5, and 10 μM) for 0, 24, 48, and 72 hours to determine working concentrations of thymoquinone. Viability of amoeba was determined by Trypan blue stating of the amoeba for all time points. For subsequent proliferation studies, thymoquinone was prepared in HL5 and added to 5x 10⁴ cells/mL at 0, 2.5, 5, and 7.5μM. Cell counts and trypan blue staining for viability was obtained by hemocytometer at 24, 48, and 72hr in accordance with previously published studies [10 (link)].