The phenolic content and antioxidant activity of infusions from Mediterranean medicinal plants

Industrial Crops and Products

Volume 43, May 2013, Pages 465–471

• Sandra Gonçalves,
• Diogo Gomes,
• Patrícia Costa,
• Anabela Romano^,

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doi:10.1016/j.indcrop.2012.07.066

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Abstract

We prepared cold and hot water infusions from ten Mediterranean medicinal plant species and compared their total phenolic content, capacity to scavenge hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, ability to reduce Fe³⁺ and chelate Fe²⁺, and ability to inhibit Fe²⁺-induced lipid peroxidation in mouse brain homogenates. In all ten species, the phenolic content of hot infusions (from 147.05 ± 2.32 to 1359.10 ± 33.18 μmol_GAE g_dw⁻¹) was significantly greater than that of cold infusions (from 106.11 ± 8.10 to 1006.05 ± 54.43 μmol_GAE g_dw⁻¹) but the difference was greatest in Lavandula viridis. All of the extracts contained antioxidants, but infusions from Myrtus communis, Pistacia lentiscus, L. viridis and Cistus albidus were the most potent and provided evidence that the free radical scavenging and metal-chelating effects of these extracts might contribute to the prevention of Fe²⁺-induced lipid peroxidation. We observed a positive correlation between the total phenolic content and the antioxidant activity as measured using all the methods listed above with the exception of hydroxyl radical scavenging. Our results provide a scientific basis for the use of these plant species in folk medicine as well as additional resources for the discovery of novel antioxidants.

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Highlights

► The phenolic content of hot infusions was greater than that of cold infusions. ► M. communis, P. lentiscus, L. viridis and C. albidus infusions were remarkably potent. ► Fe²⁺-chelating effects contribute to prevent Fe²⁺-induced lipid peroxidation. ► Data provide a scientific basis for the use of the studied plants as folk remedies.

Abbreviations

• DPPH, 2,2-diphenyl-1-picrylhydrazyl;
• F–C reagent, Folin–Ciocalteu reagent;
• GAE, gallic acid equivalents;
• MDA, malondialdehyde;
• ROS, reactive oxygen species;
• TBA, thiobarbituric acid;
• TBARS, thiobarbituric acid reactive substances;
• TCA, trichloroacetic acid;
• TE, trolox equivalents;
• Trolox, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid

Keywords

• DPPH;
• Fe²⁺ chelation;
• Free radicals;
• Lipid peroxidation;
• Phenolics;
• Reducing power

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Copyright © 2012 Elsevier B.V. All rights reserved.