Vitamin C preserves the cardio-protective paraoxonase activity of high-density lipoprotein during oxidant stress.

HDL-associated paraoxonase (PON) antioxidant enzyme activity is cardio-protective. We investigated whether vitamin C prevented loss of PON activity from HDL during oxidant stress. HDL was incubated with either hydrophilic or lipophilic peroxyl radical initiators in the absence (control) or presence of vitamin C (50 and 100 micromol/L).