PROTECTIVE EFFECT OF AQUEOUS BARK EXTRACT OF TERMINALIA ARJUNA ON CU 2+ - ASCORBATE INDUCED OXIDATIVE STRESS IN VITRO: INVOLVEMENT OF ANTIOXIDANT MECHANISM(S)

Cu2+-ascorbate induced oxidative stress in goat red blood cell- an established model of oxidative stress in vitro was used for the present investigation. Terminalia arjuna (TA) an important medicinal plant has been found to be of therapeutic benefit in the treatment of cardiovascular diseases and reactive oxygen species (ROS) play a critical role in the pathogenesis of various cardiovascular diseases. The cardioprotective effects of TA are thought to be caused by the antioxidant nature of several of the constituents of TA extract. In a preliminary attempt to characterize the antioxidant properties of TA, our present studies indicate that aqueous TA bark extract is capable of protecting against oxidative stress as is evident from its effect on the biomarkers of oxidative stress, the antioxidant enzymes and the ROS scavenging activities. Aqueous TA bark extract decreased the level of lipid peroxidation, increased the reduced glutathione content and decreased the protein carbonyl content in Cu 2+-ascorbate treated RBCs. The activities of antioxidant enzymes, catalase and superoxide dismutase (SOD), were also found to be protected by this aqueous bark extract. Aqueous bark extract of TA was found to scavenge hydroxyl radical in a chemically defined system. It also exhibited superoxide anion radical scavenging activity.