Fe(III) reductive and free radical-scavenging properties of summer savory (Satureja hortensis L.) extract and subfractions

Satureja hortensis L. (summer savory) is an annual herb belonging to the family Lamiaceae. It is used as a condiment and as a plant in traditional folk medicine to treat infectious diseases and disorders. A number of studies have suggested that the activity of Satureja hortensis may relate to the antioxidant properties of its secondary metabolites. Therefore, this study attempts to characterise the antioxidant properties of an acidified aqueous methanol extract from commercially available material using Fe(III) reductive and DPPH., ABTS(.+) and hydroxyl free radical-scavenging assays. The crude extract demonstrated promising in vitro activity and thus was further fractionated, by liquid-liquid partitioning against water, to determine which fraction possessed the most potent activity. The ethyl acetate-soluble fraction was the most effective fraction, with reductive activity of 2648 +/- 41.4 mumol ascorbic acid/g extract, and DPPH- and hydroxyl radical-scavenging IC50 concentrations of 138 +/- 6.0 and 45.0 +/- 7.0 mug/ml, respectively. The TEAC value for this fraction was 2.59 +/- 0.06 mM Trolox. The experimental results are discussed and potential applications are explored. (C) 2004 Elsevier Ltd. All rights reserved.