In vitro antioxidant activity of piperine

Oxygen radical injury and lipid peroxidation have been suggested as major c auses of atherosclerosis, cancer liver disease and the aging process. Piper ine, having an antiinflammatory effect, has been demonstrated in in vitro e xperiments to protect against oxidative damage by inhibiting or quenching f ree radicals and reactive oxygen species and hydroxyl radicals. The effect on lipid peroxidation was also examined and IC50 values were calculated. Pi perine was found to act as a hydroxyl radical scavenger at low concentratio ns but at higher concentrations, it activated the fenton reaction resulting in increased generation of hydroxyl radicals. Whereas it acts as a powerfu l superoxide scavenger and IC50 is 1.82 mM, a 52% inhibition of lipid perox idation was observed at a dose of 1400 mu M with an IC50 of 1.23 mM. The re sults depict that piperine possesses direct antioxidant activity against va rious free radicals. This study also opens newer views on the potential eff icacy of piperine in protecting tissues from peroxidative damage. (C) 2000 Prous Science. All rights reserved.