Define Antioxidant Activity of manganese?

As Mn is a component of mitochondrial Superoxide Dismutase (SOD), it can protect against oxidative damage. In-vitro experiments have indicated that Mn scavenged superoxide radicals at nanomolar concentration whereas hydroxy radicals were scavenged at macromolar concentrations. Thus, Mn deficiency could damage mitochondrial membrane by depressing the activity of SOD. Although, a little work has been done in humans, depressed activity of the enzyme has been reported in animals.