Intake of Heated Leaf Extract of Coriandrum sativum Contributes to Resistance to Oxidative Stress via Decreases in Heavy Metal Concentrations in the Kidney

Coriandrum sativum (coriander) is an annual herb of the Apiaceae family and has been used as a traditional remedy. Here we examined whether heated leaf extract of coriander decreases the concentrations of heavy metals in tissues. Male ddY mice were given a drinking water containing 0.25% of heated leaf extract of coriander for 8weeks. Eight weeks after the intake, the concentrations of zinc, iron, copper, arsenic, and cadmium were measured in the liver and kidney. The intake of coriander did not modify the concentrations of all heavy metals tested in the liver, but decreased the concentrations of iron, arsenic, and cadmium in the kidney. Because heavy metals can induce oxidative stress, the effect of coriander intake on hydrogen peroxide-induced oxidative stress was compared between slices from the kidney and liver. The slices were immersed in Ringer solution containing 100M hydrogen peroxide and aminophenyl fluorescein (APF), a probe for detecting reactive oxygen species (ROS). APF fluorescence was markedly increased in the control kidney slices, while the increase was completely blocked in kidney slices from coriander intake group. In contrast, APF fluorescence was also markedly increased in the control liver slices, while the increase was not blocked by coriander intake. The present study indicates that intake of coriander leaf extract contributes to powerful resistance to oxidative stress in the kidney, probably via decreased concentrations in heavy metals. It is likely that decrease in arsenic concentration to the detection limit is a major factor for the resistance.