Oxidative stress which is increased in obesity plays an important role in the development of diabetes and cardiovascular diseases in people. The objective was to explore possible mechanism of antioxidant activity of medicinal plants with a long history of safety is rich in polyphenolic components that have been shown to improve the action of insulin in-vitro, in animal studies and to possess in vitro antioxidant activity. Recently, free radical induced lipid peroxidation has gained much importance because of its involvement in several pathologies such as ageing, wound healing, oxygen toxicity, liver disorders, inflammation etc. Many plants are known to have beneficial therapeutic effects as noted in the traditional Indian system of medicine 'Ayurveda'.