Effect in sickle-cell anemia was determined by counting the sickle-shaped cells in a blood sample taken from a sickle-cell patient. Upon exposure of the cells to 2, 4, 8 and 10 mg/ml of the extract, five readings were taken every 30 min. Para-hydroxybenzoic acid (5 mg/ml) was used as positive control, whereas the negative control was 0.9 % ....