Influence of Honey on the Suppression of Human Low Density Lipoprotein (LDL) Peroxidation (In vitro)

Ahmed G. Hegazi; Faten K. Abd El-Hady

Disclosures

Evid Based Complement Alternat Med. 2009;6(1):113-121. 

In This Article

Abstract and Introduction

Abstract

The antioxidant activity of four honey samples from different floral sources (Acacia, Coriander, Sider and Palm) were evaluated with three different assays; DPPH free radical scavenging assay, superoxide anion generated in xanthine-xanthine oxidase (XOD) system and low density lipoprotein (LDL) peroxidation assay. The dark Palm and Sider honeys had the highest antioxidant activity in the DPPH assay. But all the honey samples exhibited more or less the same highly significant antioxidant activity within the concentration of 1mg honey/1 ml in XOD system and LDL peroxidation assays. The chemical composition of these samples was investigated by GC/MS and HPLC analysis, 11 compounds being new to honey. The GC/MS revealed the presence of 90 compounds, mainly aliphatic acids (37 compounds), which represent 54.73, 8.72, 22.87 and 64.10% and phenolic acids (15 compound) 2.3, 1.02, 2.07 and 11.68% for Acacia, Coriander, Sider and Palm honeys. In HPLC analysis, 19 flavonoids were identified. Coriander and Sider honeys were characterized by the presence of large amounts of flavonoids.

Introduction

Free radicals and reactive oxygen species (ROS) have been implicated in contributing to aging and many disease states including cancer and atherosclerosis. Antioxidants are compounds that can delay or inhibit the oxidation of lipids or other molecules by inhibiting the initiation or propagation of oxidizing chain reactions.[1] Many synthetic antioxidant components have shown toxic and/or mutagenic effects, which directed most of the attention on the naturally occurring antioxidants. Their use has mainly centered on prevention, and the maintenance of health.[2,3,4,5]

The oxidative modification hypothesis of atherosclerosis predicts that low-density lipoprotein (LDL) oxidation is an early event in atherosclerosis.[6] Therefore, inhibition of LDL oxidation might be an important step in preventing atherogensis.[7,8]

Humans protect themselves from (ROS), in part, by absorbing dietary antioxidants. Thus, increasing the body's antioxidant content may help protect against cellular damage and the development of chronic diseases. Research indicates that honey contains numerous phenolic and non-phenolic antioxidants,[9] the amount and type of which depends largely upon the floral source of the honey. Darker honeys are generally higher in antioxidant content than lighter honeys and have been shown to be similar in antioxidant capacity to many fruits and vegetables on a dry weight basis.[9,10,11,12] Honey has a great potential to serve as a natural food antioxidant. The antioxidant activity of honey, however, varies greatly depending on the honey floral source.[10,13]

A strong correlation between antioxidant activity of honeys and total phenolic content was previously demonstrated.[10] In several studies on European honeys, Ferreres and co-workers have shown that honeys have a rich phenolic profile consisting of benzoic acids and their esters, cinnamic acids and their esters and flavonoid aglycones.[14,15,16,17,18] In general, the antioxidant capacity of honey appeared to be a result of the combined activity of a wide range of compounds including phenolics, peptides, organic acids, enzymes and possibly other minor components. The phenolic compounds contributed significantly to the antioxidant capacity of honey, but were not solely responsible for it.[9] However, little information is available on the phenolic and non-phenolic profiles of honeys from floral sources common in Arabic region. Characterization of the phenolics and other components in honey that might be responsible for its antioxidant effects is essential to improve our knowledge about honey as a source of antioxidants.

The objective of this study was, therefore, to identify and quantify the chemical composition of four honey samples from different floral sources by GC/MS and HPLC and to find out (for the first time) the highly effective antioxidant one which could protect the human LDL against copper-induced oxidation in vitro—a study that provides a primary evidence—for further in vivo studies.

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