Antioxidant activities of aqueous extracts of purslane (Portulaca oleracea subsp sativa L.)

Abstract

The antioxidant activities of the infusion and aqueous extracts of purslane (Portulaca oleracea subsp. sativa L.) were investigated. Different antioxidant tests were employed, namely reducing power, total antioxidant activity, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, hydroxyl radical scavenging, metal chelating activities and P-carotene bleaching effect. In addition, the results were compared with natural and synthetic antioxidants, e.g. alpha-tocopherol, butylated hydroxytoluene and butylated hydroxyanisole. The levels of anthocyanins, total flavonoids and total phenolics of the extracts were also determined. Total phenolic and total flavonoid contents of the infusion were found to be higher than those of the aqueous extract. Infusion of purslane exhibited a strong Fe2+ chelating effect, free radical scavenging activity, hydrogen peroxide scavenging ability, and hydroxyl radical scavenging activity. Antioxidant activity of the aqueous extract increased with increased concentrations, in the range of 20-100 mu g/ mL. The aqueous extract also exhibited a strong superoxide radical scavenging activity. This study showed that purslane extracts exhibited antioxidant activity in all tests and the extracts could be considered as a source of natural antioxidants.