Identification and antioxidant potential of flavonoids and low molecular weight phenols in olive cultivar chemlali growing in tunisia.

Auteur(s) :
Bouaziz M., Grayer RJ., Simmonds MS., Damak M., Sayadi S.
Date :
Jan, 2005
Source(s) :
Journal of agricultural and food chemistry. #53:2 p236-41
Adresse :
Laboratoire des Bio-procedes, Centre de Biotechnologie de Sfax, B.P. K, 3038 Sfax, Tunisia.

Sommaire de l'article

Increasing interest in phenolic compounds in olives is due to their antioxidant and health-enhancing properties. In this study the phenolics in fruits of the Tunisian olive cultivar Chemlali were extracted by methanol-water and fractionated using Sephadex LH-20 column chromatography. The identification of phenolic monomers and flavonoids was based on separation by high-performance liquid chromatography equipped with a diode array detector followed by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry analysis. Oleuropein, a secoiridoid glycoside esterified with a phenolic acid, was the major compound. Eight phenolic monomers and 12 flavonoids were also identified in Chemlali olives. Five flavonoids were isolated and purified using Sephadex LH-20 column chromatography and preparative paper chromatography. The antioxidant activity of the extract and the purified compounds was evaluated by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl and by using the beta-carotene-linoleate model assay. Acid hydrolysis of the extract enhanced its antioxidant activity. Hydroxytyrosol and quercetin showed antioxidant activities similar to that of 2,6-di-tert-butyl-4-methylphenol. A hydroxyl group at the ortho position at 3′ on the B ring of the flavonoid nucleus could contribute to the antioxidant activity of the flavonoids.

Source : Pubmed