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Isolation and evaluation of antioxidants from leaves of a Tunisian cultivar olive tree

Isolation and evaluation of antioxidants from leaves of a Tunisian cultivar olive tree Quantitative and qualitative determinations of phenolic compounds were carried out on Chemlali olive leaves, a by‐product of olive tree pruning. The evolution of the amount of the major phenolic compound was monitored from July 2003 to March 2004. Quantitative analysis was performed by high‐performance liquid chromatography (HPLC), which revealed that oleuropein was always the major compound. Its concentration reached 6.8 g per 100 g of fresh olive leaves, while monomeric phenols were the minor compounds. Beside oleuropein, six flavonoids (luteolin 7‐O‐glucoside, luteolin 7‐O‐rutinoside, apigenin 7‐O‐glucoside, rutin, luteolin and apigenin) were identified. The identification was based on separation by HPLC equipped with a diode array detector, followed by liquid chromatography‐mass spectrometry analysis. A relative high amount of purified hydroxytyrosol (2.3 g per 100 g of fresh olive leaves) was obtained in short time by a simple hydrolysis reaction of Olea europaea leaf extract and by purification using a C‐18 silica gel column. The antioxidant activities of the extracts and the purified compounds were evaluated by measuring the radical‐scavenging effect on 1,1‐diphenyl‐2‐picrylhydrazyl and by using the β‐carotene linoleate model assay. Hydroxytyrosol and hydrolysate products have the highest antioxidant activities. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png European Journal of Lipid Science and Technology Wiley

Isolation and evaluation of antioxidants from leaves of a Tunisian cultivar olive tree

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References (31)

Publisher
Wiley
Copyright
Copyright © 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
ISSN
1438-7697
eISSN
1438-9312
DOI
10.1002/ejlt.200501166
Publisher site
See Article on Publisher Site

Abstract

Quantitative and qualitative determinations of phenolic compounds were carried out on Chemlali olive leaves, a by‐product of olive tree pruning. The evolution of the amount of the major phenolic compound was monitored from July 2003 to March 2004. Quantitative analysis was performed by high‐performance liquid chromatography (HPLC), which revealed that oleuropein was always the major compound. Its concentration reached 6.8 g per 100 g of fresh olive leaves, while monomeric phenols were the minor compounds. Beside oleuropein, six flavonoids (luteolin 7‐O‐glucoside, luteolin 7‐O‐rutinoside, apigenin 7‐O‐glucoside, rutin, luteolin and apigenin) were identified. The identification was based on separation by HPLC equipped with a diode array detector, followed by liquid chromatography‐mass spectrometry analysis. A relative high amount of purified hydroxytyrosol (2.3 g per 100 g of fresh olive leaves) was obtained in short time by a simple hydrolysis reaction of Olea europaea leaf extract and by purification using a C‐18 silica gel column. The antioxidant activities of the extracts and the purified compounds were evaluated by measuring the radical‐scavenging effect on 1,1‐diphenyl‐2‐picrylhydrazyl and by using the β‐carotene linoleate model assay. Hydroxytyrosol and hydrolysate products have the highest antioxidant activities.

Journal

European Journal of Lipid Science and TechnologyWiley

Published: Aug 1, 2005

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