<i>Origanum</i> species native to the island of Crete: <i>in vitro</i> antioxidant characteristics and liquid chromatography–mass spectrometry identification of major polyphenolic components

<div><p>Extracts from three <i>Origanum</i> species, including <i>Origanum microphyllum</i>, <i>Origanum dictamnus</i> and <i>Origanum vulgare</i> subsp. <i>hirtum</i>, native to the island of Crete (southern Greece), were partly fractionated through successive partition with ethyl acetate and <i>n</i>-butanol. All the fractions obtained were profiled with regard to their major polyphenolic constituents, using liquid chromatography-diode array-mass spectrometry. Furthermore, the antioxidant potency of each fraction was assessed by estimating the antiradical activity (<i>A</i>_AR) and the hydroxyl free radical scavenging activity (SA_HFR). The chromatographic analyses revealed a rich profile mainly for the ethyl acetate fractions, composed principally by flavones, which were accompanied by a limited number of phenylpropanoids, flavanones and dihydroflavonols. The highest values of antioxidant activity were displayed by the ethyl acetate extract of <i>O. dictamnus</i>, which also possessed the richest polyphenolic composition.</p></div