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

Abstract

Extracts from three Origanum species, including Origanum microphyllum, Origanum dictamnus and Origanum vulgare subsp. hirtum, native to the island of Crete (southern Greece), were partly fractionated through successive partition with ethyl acetate and n-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 (A_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 O. dictamnus, which also possessed the richest polyphenolic composition.

Keywords::

• antioxidants
• liquid chromatography-diode array-mass spectrometry
• flavonoids
• Origanum
• polyphenols

Acknowledgements

This work is supported by the project ‘SysTerp – A systems approach into the production of plant and algal diterpenes with high industrial and pharmaceutical value’, which is implemented under the ‘COOPERATION 2009’ Action of the Operational Programme ‘COMPETITIVENESS AND ENTREPRENEURSHIP’ and is co-funded by the European Social Fund (ESF) and National Resources.