Free radicals play an important role in some pathogenesis of various serious diseases, such as neurodegenerative disorders, cancer, liver cirrhosis, cardiovascular diseases, atherosclerosis, cataracts, diabetes and inflammation. One of the methods for measuring antioxidant potential is through determining the free radical inhibitory ability of different antioxidant by using very stable free radicals, such as DPPH in methanol solution. DPPH is a stable nitrogen-centred free radical, and its colour changes from violet to yellow when is reduced by either the process
of hydrogen- or elctron-donation. Substances which are able to perform this reaction can be considered as antioxidants and therefore radical scavengers