Optimized Extraction of Antioxidants From Olive Leaves Using Augmented Simplex Centroid DesignAnalytical Letters

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Authors
Ines Sifaoui, Elsa Mecha, Andreia Silva, Nadia Chammem, Mondher Mejri, Manef Abderabba, Maria Rosario Bronze
Year
2015
DOI
10.1080/00032719.2015.1104320
Subject
Analytical Chemistry / Spectroscopy / Clinical Biochemistry / Electrochemistry / Biochemistry / Biochemistry, medical

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Analytical Letters

ISSN: 0003-2719 (Print) 1532-236X (Online) Journal homepage: http://www.tandfonline.com/loi/lanl20

Optimized Extraction of Antioxidants From Olive

Leaves Using Augmented Simplex Centroid Design

Ines Sifaoui, Elsa Mecha, Andreia Silva, Nadia Chammem, Mondher Mejri,

Manef Abderabba & Maria Rosario Bronze

To cite this article: Ines Sifaoui, Elsa Mecha, Andreia Silva, Nadia Chammem, Mondher Mejri,

Manef Abderabba & Maria Rosario Bronze (2015): Optimized Extraction of Antioxidants

From Olive Leaves Using Augmented Simplex Centroid Design, Analytical Letters, DOI: 10.1080/00032719.2015.1104320

To link to this article: http://dx.doi.org/10.1080/00032719.2015.1104320

Accepted author version posted online: 09

Nov 2015.

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Optimized Extraction of Antioxidants from Olive Leaves

Using Augmented Simplex Centroid Design

Ines Sifaoui

Laboratoire de matériaux- molécules et applications, IPEST, University of Carthage, Tunisia

Elsa Mecha

Analytical Chemistry Laboratory, Instituto de Tecnologia Química e Biológica, Universidade

Nova de Lisboa, Oeiras, Portugal

Andreia Silva

Analytical Chemistry Laboratory, Instituto de Tecnologia Química e Biológica, Universidade

Nova de Lisboa, Oeiras, Portugal

Nadia Chammem

Laboratoire d’Ecologie et de Technologie Microbienne, INSAT, University of Carthage, Tunisia

Mondher Mejri

Laboratoire de matériaux- molécules et applications, IPEST, University of Carthage, Tunisia

Manef Abderabba

Laboratoire de matériaux- molécules et applications, IPEST, University of Carthage, Tunisia

Maria Rosario Bronze

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Analytical Chemistry Laboratory, Instituto de Tecnologia Química e Biológica, Universidade

Nova de Lisboa, Oeiras, Portugal

Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal

Faculdade de Farmácia da Universidade de Lisboa, Lisboa, Portugal

Address correspondence to Ines Sifaoui. E-mail: ines.sifaoui@hotmail.com

Received 03 April 2015; accepted 02 October 2015.

Supertitle: Liquid Chromatography

Abstract

The olive tree historically provided economic benefits to the countries in Mediterranean basin as a source of products contributing to health promotion. Some of the health benefits attributed to olive tree leaves are related to phenolic composition. In this study, a 10-point augmented simplex-centroid design was used to formulate a three-component mixture system using water, ethanol and methanol, adequate for the extraction of phenolics from olive leaves. Phenolic and flavonoid content, antioxidant activity with 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), oleuropein, and luteolin7- O-glucoside concentrations were selected as responses. The optimal extraction mixture was: 12.7% water, 14.8% ethanol, and 72.5% methanol. The yields of total phenolic and flavonoid compounds, oleuropein, and luteolin-7-O-glucoside were 163.69 ± 6.35 mg gallic acid g1, 114.69 ± 3.56 mg rutin g1, 858.29 µg g1, and 21.04 µg g1 dry weight of olive leaves. The antioxidant capacity was 238.71 ± 4.35 mM equivalent Trolox per g1 dry weight of olive leaves.

Keywords: antioxidants, mixture design, olive leaves

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INTRODUCTION

Recently, many studies have correlated the low incidence of coronary heart disease in the

Mediterranean basin to dietary habits from the population. The Mediterranean Diet was nominated as a World’s Intangible Cultural Heritage by the United Nations Educational,

Scientific and Cultural Organization (Cicatelli et al. 2013). This type of diet is characterized by an abundance of foods such as vegetables, fruits, and especially products from olive trees (Olea europeaea, Oleaceae) which are rich in phenolics. This tree is widely cultivated in the

Mediterranean countries and historically provided economic benefits to the countries in this area.

Olive fruits have been extensively used as food and in traditional medicine (Japón-Luján and

Luque de Castro 2006).The olive oil is the principal source of culinary and dressing fat (Kaeidi et al. 2011; Musumeci et al. 2013). Numerous publications reported the health benefits of olive oil, especially to protect against coronary heart disease and to inhibit oxidative stress and its damage on the cells (Venturini et al. 2015). In addition to olive fruit, the leaves of this tree have been used for medicinal purposes, and were introduced recently into the European pharmacopoeia (Scheffler et al. 2008). Phytochemical studies of olive leaf extracts led to the isolation of secoiridoid and triterpene compounds (Sifaoui et al. 2014). Oleuropein and related derivatives are a major class in olive leaf extracts. Several studies have reported antioxidant, hypoglycemic, antihypertensive, antimicrobial, anti-tumoral, anti-atherosclerotic, and antiviral activities, including anti-human immunodeficiency virus properties of olive leaves (El and

Karakaya 2009).

Diverse methods have been used to isolate the bioactive molecules present in the olive products that include solid/liquid extraction with organic solvents, ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, and high-pressure processes

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N ov em be r 2 01 5 4 (Taamalli et al. 2012). Solid/liquid extraction is one of the conventional techniques for plant material. In order to attain optimal yields, the temperature, the type of solvents used, the ratio (solvent: plant material), the particle size of the sample, and the time of extraction must be optimized. Having the goal of reducing the number of experimental trials, Response Surface