Radical Scavenging Potential of Terminalia Arjuna Bark

The antioxidant potency of methanolic and aqueous extract of Terminalia arjuna bark was investigated employing various established in vitro systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH)/hydroxyl, lipid peroxidation in membrane liposome vesicles, reducing power and metal ion chelation. As free radicals are highly reactive, short-lived, toxic molecules that have one or more unpaired electrons and can damage DNA, proteins, lipids and carbohydrates within the tissue. The main cause of mortality and morbidity in the western world is atherosclerosis, the accumulation of oxysterols, cholesterol and peroxide lipids in arteries, generated by free radicals which lead to heart attack. Hence, there has been an increased interest in the application of antioxidants to medical treatment as information are constantly gathered, linking the development of human diseases to oxidative stress that leads to the generation of free radicals. Understanding the efficacy and mechanism of the biologically important radicals with natural antioxidants is the first step towards the development of future therapeutic agents. One such tree is T. arjuna wherein, the decoction of T. arjuna bark with cane sugar and boiled cow's milk is highly recommended for endocarditis, pericarditis, angina and is extensively used in ayurvedic medicine, particularly as cardiac tonic. However, there is no evidence for the antioxidant or radical scavenging activity of T. arjuna. Among the extracts, the methanolic and aqueous extracts showed high antioxidant activity measured as scavenging of DPPH, hydroxyl radicals and lipid peroxidation. Both the aqueous and methanolic extracts exhibited strong reducing power and metal chelating activity. The antioxidant activity correlates with the phenolic content of the extracts. These results demonstrate the antioxidant potency of the bark extracts which could be the basis for its alleged health promoting potential. T. arjuna could serve as a new source of natural antioxidants or nutraceuticals with potential applications to reducing the level of oxidative stress and related health benefits.