Objective To observe the effects of anthocyanin-rich extract from black rice on reactive oxygen species (ROS) and mitochondrial membrane potential of leukemia HL-60 cells and human lymphocytes. Methods Using a ROS probe (2

7-dichloro fluorescein diactate

DCFH-DA) and rhodamine-123

the levels of ROS and mitochondrial membrane potential of HL-60 cells and human lymphocytes were determined by flow cytometry and laser confocal scanning microscopy. Results The extract had no significant effects on ROS level of human lymphocytes after 2-hour and 24-hour treatment

while it significantly increased ROS level of HL-60 cells after 2-hour treatment (P0.01)

then gradually decreased ROS level

which was significantly lower than the level of lymphocytes after 12hour treatment(P0.01). After 24-hour treatment

the extract had no significant effect on mitochondrial membrane potential of human lymphocytes

while significantly decreased that of HL-60 cells. Conclusion Anthocyanin-rich extract from black rice can significantly influence ROS level of HL-60 cells and decrease mitochondrial membrane potential of HL-60 cells

but it has no significant effects on human lymphocytes.