FIG. 4.

Measurement of reactive oxygen species (ROS) in L5178Y cells treated with Ginkgo biloba leaf extract (A), quercetin (B), and kaempferol (C). L5178Y cells were treated with different concentrations of G. biloba leaf extract (0.2—1.2 mg/ml), quercetin (10–100μM), and kaempferol (10–200μM). The ROS values were measured at 10 min, 0.5–6 h, and 24 h after adding the chemicals. Data are presented as mean ± 1 standard deviation measured from at least three independent experiments with four parallel samples per concentration in each experiment.