Antioxidant activity of mediterranean plant leaves: Occurrence and antioxidative importance of α‐tocopherol

Chevolleau, Sylvie; Mallet, Jeanne; Debal, A.; Ucciani, E.

doi:10.1007/bf02542606

Cited by 35 publications

(17 citation statements)

References 15 publications

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“…Other situations where the knowledge of total antioxidant activity can be useful include the analysis of changes in plasma antioxidant activity related to oxidative stress, or the understanding of structure-activity relationships of pure antioxidant species. Because of its simplicity and the ch eap reagents i t uses, the phosphomlybdenum method is an alternative to t he m ethods a lready available for the evaluation of total antioxidant capacity (6,21). Besides, these methods yield the results of t heir ev aluations as a s emiquantitative antioxidant activity co efficient ( AAC).…”

Section: × 10mentioning

confidence: 99%

Spectrophotometric Quantitation of Antioxidant Capacity through the Formation of a Phosphomolybdenum Complex: Specific Application to the Determination of Vitamin E

Prieto

Pineda

Aguilar

1999

Analytical Biochemistry

4,807

2,517

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A spectrophotometric method has been developed for the quantitative determination of antioxidant capacity. The assay is based on the reduction of Mo(VI)to Mo(V) by the sample analyte and the subsequent formation of a green phosphate/Mo(V) complex atacidic pH. The method has been optimized and characterized with respect to linearity interval, repetitivity and reproducibility, and molar absorption coefficients for the quantitation of several antioxidants, including vitamin E. The phosphomolybdenum method, in combination with hexane monophasic extraction, has also been adapted for the specific determination of vitamin E in seeds. The results obtained with the proposed method were validated by comparison with a standard HPLC method. The phosphomolybdenum method is routinely applied in our laboratory to evaluate the total antioxidant capacity of plant extracts and to determine vitamin E in a variety of grains and seeds, including corn and soybean.There is an increasing interest in the use and measurement of antioxidants in food, pharmaceutical, and cosmetic industries. This interest is rooted in the cumulative evidence that connects oxidative stress with numerous d egenerative d isorders ranging f rom p remature aging, pr ostaglandin-mediated i nflammatory processes, cancer, and a l ong series of diseases i n which free r adicals ar e implicated (1, 2). In addition, many states implement very rigorous regulations on the use of food preservatives, so that they only allow the use of natural antioxidants. Basically, these include vitamin C (ascorbic acid), vitamin E (tocopherols and tocotrienols), and relatively complex extracts from a number of plant species (Rosmarinus officinalis, Nerium oleander, and Myrtus comunis).The e arly works by Ch ipault et a l. (3-5) w ere t he precursors o f m any s tudies o n t he antioxidant capacity of a number of plant extracts with potential applications as preservatives in the food, cosmetics, and p harmaceutical industries (6 -12). The c urrent i nterest of our l aboratory i n t he b iosynthesis o f tocopherols in plants and in the identification of alternative sources of natural antioxidants prompted us to develop a m ethod for t he e valuation o f water-soluble a nd fa t-soluble a ntioxidant capacity. T he phosphomolybdenum method that we propose in this article is now systematically used by us in extensive screenings o f samples o f v ery different origins a nd composition i n our search f or natural sources of vitamin E and other powerful antioxidants. MATERIALS AND METHODSChemicals an d r eagents. Ammonium mo lybdate; ascorbic ac id; r educed g lutathione; b utyl hydroxytoluene (BHT);3 α-, γ-, an d δ-tocopherol; a nd t he internal standard α-tocopherol a cetate were obtained from Sigma (St. Louis, MO). HPLC gr ade methanol, h exane, ethanol, dimethyl sulfoxide, and analytical grade sodium phosphate and sulfuric a cid were from Merck (Darmstadt, Germany). All other chemicals were of analytical grade.Instrumentation. The m olecular a bsorption s pectra and absorbance a t s pecifi...

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Section: × 10mentioning

confidence: 99%

Spectrophotometric Quantitation of Antioxidant Capacity through the Formation of a Phosphomolybdenum Complex: Specific Application to the Determination of Vitamin E

Prieto

Pineda

Aguilar

1999

Analytical Biochemistry

4,807

2,517

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“…In leaves of several oak species relatively high α-tocopherol contents were found. Quercus ilex leaves showed the highest α-tocopherol content among 16 Mediterranean plant species (Chevolleau et al 1993). In winter, the α-tocopherol content of leaves of Qu.…”

Section: Comparison Between Beech and Oakmentioning

confidence: 99%

Variation of pigment composition and antioxidative systems along the canopy light gradient in a mixed beech/oak forest: a comparative study on deciduous tree species differing in shade tolerance

Hansen

Fiedler

Rank

2002

Trees

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The acclimation of leaf pigments and antioxidative systems along the vertical canopy light gradient was determined in mature European beech (Fagus sylvatica L.) and sessile oak [Quercus petraea (Matt.) Liebl.] trees in a mixed beech/oak forest in northwest Germany. The aim of the study was to investigate if the higher shade tolerance of beech, relative to oak, is correlated with characteristics of the leaf pigment composition and antioxidative systems. Both species showed a similar acclimative response to increasing light availability. Compared to shade leaves, leaves of the upper crown layer exhibited higher chlorophyll a to chlorophyll b ratios and higher contents of photoprotective carotenoids, ascorbate and glutathione per unit chlorophyll, and higher mean activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase. The comparison of beech and oak leaves sampled at crown positions with similar light environments revealed "shade-type" pigment characteristics for beech, relative to oak, whereas "sun-type" characteristics were found with respect to antioxidative systems. At a given average light availability level, leaves of F. sylvatica exhibited higher antioxidant contents and higher ascorbate peroxidase activities as compared to those of Qu. petraea. The data suggest that a higher antioxidative capacity is required in leaves of the more shade-tolerant species. The supposed higher production rate of radicals and reactive oxygen species (ROS) in beech can be explained by: (1) the lower energy utilizing capacity, as beech leaves show lower light-saturated rates of photosynthesis than oak leaves, and (2) by specific features of the photosynthetic apparatus as suggested by the pigment data. A higher ROS generation rate in beech versus oak leaves could be seen as a consequence of efficient photosynthesis under low light conditions. Therefore a high capacity of protection against oxidative stress might be a prerequisite of shade tolerance.

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“…Then, the impact of these structural variations on the antioxidant activity was evaluated by using a procedure adapted from the literature. This test was achieved in an oil-in-water (O/W) emulsion made of b-carotene, linoleic acid, H 2 O, and a nonionic surfactant [6]. These conditions could be compared to the physiological environment of the natural antioxidant.…”

mentioning

confidence: 99%

“…We chose to adapt the procedure reported by Chevolleau et al [6] to our molecules. In this test, the b-carotene is co-oxidized by linoleic acid in the presence of a nonionic surfactant such as the tween 40.…”

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confidence: 99%

Synthetic Gallic Acid Derivatives as Models for a Comprehensive Study of Antioxidant Activity

Belin

Barthélémy

Ruiz

et al. 2003

Helvetica Chimica Acta

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The synthesis and antioxidant efficiencies of amphiphilic gallic acid derivatives are reported. To specify the impact of chemical structure on the antioxidant efficiency, several structural modifications of gallic acid were performed. The following structural features were chosen: i) introduction of hydrophobic or hydrophilic residues on the gallic acid and the type of their linkage, ii) the hydrophilic and/or lipophilic character of the whole molecule. The physico-chemical studies of the different series prepared revealed that the antioxidant efficiency of this polyphenol depends clearly on the nature of the linkage with both hydrophilic and hydrophobic parts. A push-pull effect is always necessary, and ester or amide bonds seem well adapted to increase the antioxidant efficiency. Second, under the oxidation conditions applied, it was observed that the hydrophilic and/ or lipophilic character affects drastically the antioxidant activity of gallic acid derivatives. The results obtained are in accordance with the polar paradox, hydrophobic derivatives inhibit oxidation in an aqueous phase, whereas hydrophilic products are not efficient.

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Antioxidant activity of mediterranean plant leaves: Occurrence and antioxidative importance of α‐tocopherol

Cited by 35 publications

References 15 publications

Spectrophotometric Quantitation of Antioxidant Capacity through the Formation of a Phosphomolybdenum Complex: Specific Application to the Determination of Vitamin E

Spectrophotometric Quantitation of Antioxidant Capacity through the Formation of a Phosphomolybdenum Complex: Specific Application to the Determination of Vitamin E

Variation of pigment composition and antioxidative systems along the canopy light gradient in a mixed beech/oak forest: a comparative study on deciduous tree species differing in shade tolerance

Synthetic Gallic Acid Derivatives as Models for a Comprehensive Study of Antioxidant Activity

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