Antioxidant activities of polyphenols from sage (Salvia officinalis)

The antioxidant activities of the sage polyphenols, consisting of flavone glycosides and a range of rosmarinic acid derivatives, were evaluated for their capacity to scavenge DPPH and superoxide anion radicals and also to reduce Mo(VI) to Mo(V). The rosmarinic acid derivatives all showed potent antioxidant activity in three test systems and their capacity to reduce Mo(VI) to Mo(V) and their superoxide radical scavenging activities, with values ranging from 220 to 300 SOD units/mg, in particular, were 4–6 and 15–20 times greater than trolox, respectively. The high SOD activity of rosmarinic acids could be attributed to the radical-scavenging catechols and the xanthine oxidase-inhibiting caffeic acid moieties contained in them. The antioxidant activity of the flavonoids was variable and those with a catechol B-ring (luteolin glycosides) were more active than those without (apigenin glycosides).