Identification and Antioxidant Potential of Flavonoids and Low Molecular Weight Phenols in Olive Cultivar Chemlali Growing in Tunisia

• Published in: Journal of agricultural and food chemistry 2005-01, Vol.53 (2), p.236-241
• Main Authors: Bouaziz, Mohamed, Grayer, Renee J, Simmonds, Monique S. J, Damak, Mohamed, Sayadi, Sami
• Format: Article
• Language: English
• Subjects: antioxidant activity; antioxidants; Antioxidants - analysis; Antioxidants - pharmacology; beta Carotene; Biological and medical sciences; Biphenyl Compounds; Chromatography, High Pressure Liquid; cultivars; Feeding. Feeding behavior; flavonoids; Flavonoids - analysis; Flavonoids - pharmacology; Fruit - chemistry; fruit composition; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Iridoids; Molecular Weight; Olea - chemistry; Olea - growth & development; Olea europaea; oleuropein; olives; phenolic compounds; Phenols - analysis; Phenols - chemistry; Phenols - pharmacology; Picrates - chemistry; Pyrans - analysis; Tunisia; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf048859d

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 β-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. Keywords: Chemlali olive; phenolics; flavonoids; acid hydrolysis; antioxidant