Effects of hexanic fraction (HEX) and SF5 hexanic subfraction on K562 leukemia cell growth. (A) 30 μg/mL, (B) 50 μg/mL. Cells (2.5 × 105/mL) were cultured for 24, 48 and 72 h either in the absence (control) or presence of HEX, SF5 or methotrexate (MTX, 50 μg/mL). Viable cells were counted by Trypan blue dye exclusion. Results represent the mean ± SD of three independent experiments. ap < 0.05, bp < 0.01 and cp < 0.001, versus control by Student’s t test.