Activity of artichoke leaf extract on reactive oxygen species in human leukocytes.

Artichoke leaf extract was studied in human leukocytes for activity against oxidative stress using flow cytometry and dichlorofluorescin diacetate as a fluorescence probe. It produces a concentration-dependent inhibition of oxidative stress when cells are stimulated with agents that generate reactive oxygen species (ROS): hydrogen peroxide, phorbol-12-myristate-13-acetate (PMA), and N-formyl-methionyl-leucyl-phenylalanine (FMLP). Cynarin, caffeic acid, chlorogenic acid, and luteolin, constituents of artichoke leaf extract, also show a concentration-dependent inhibitory activity in the above models, contributing to the antioxidant activity of the extract in human neutrophils.