Phenolic compounds of plants fall into several categories; chief among these are the flavonoids which have potent antioxidant activities (Nunes et al., 2012). Flavonoids are naturally occurring in plants and are thought to have positive effects on human health. Phenolic compounds exhibit considerable free-radical scavenging activity, which is determined by their reactivity as hydrogen- or electron- donating agents, their reactivity with other antioxidants and their metal chelating properties, as well as the stability of the resulting antioxidant-derived radicals (Wojdylo et al., 2007).