Dietary Phytochemicals Promote Health by Enhancing Antioxidant Defence in a Pig Model.

Sophie N B Selby-Pham,Jeremy J Cottrell,Ken Ng,Frank R Dunshea,Louise E Bennett,Kate S Howell

doi:10.3390/nu9070758

Abstract

Phytochemical-rich diets are protective against chronic diseases and mediate their protective effect by regulation of oxidative stress (OS). However, it is proposed that under some circumstances, phytochemicals can promote production of reactive oxygen species (ROS) in vitro, which might drive OS-mediated signalling. Here, we investigated the effects of administering single doses of extracts of red cabbage and grape skin to pigs. Blood samples taken at baseline and 30 min intervals for 4 hours following intake were analyzed by measures of antioxidant status in plasma, including Trolox equivalent antioxidant capacity (TEAC) and glutathione peroxidase (GPx) activity. In addition, dose-dependent production of hydrogen peroxide (H2O2) by the same extracts was measured in untreated commercial pig plasma in vitro. Plasma from treated pigs showed extract dose-dependent increases in non-enzymatic (plasma TEAC) and enzymatic (GPx) antioxidant capacities. Similarly, extract dose-dependent increases in H2O2 were observed in commercial pig plasma in vitro. The antioxidant responses to extracts by treated pigs were highly correlated with their respective yields of H2O2 production in vitro. These results support that dietary phytochemicals regulate OS via direct and indirect antioxidant mechanisms. The latter may be attributed to the ability to produce H2O2 and to thereby stimulate cellular antioxidant defence systems.

Highlights

A phytochemical-rich diet is strongly associated with reducing the risk of chronic diseases including cancer [1], cardiovascular [2], and neurodegenerative diseases [3]
All chemicals including gallic acid, Folin-Ciocalteu reagent, sodium carbonate (Na2 CO3 ), hydrogen peroxide (H2 O2 ), sulfuric acid (H2 SO4 ), xylenol orange, Iron(II) sulphate (FeSO4 ), butylated hydroxytoluene (BHT), tris(hydroxymethyl)aminomethane (Tris), glycine, citrate, urea, hydrochloric acid (HCl), Trolox, bathocuproinedisulfonic acid sodium salt (BCS), copper(II) chloride (CuCl2 ), methanol, formic acid, acetonitrile, L-histidine, (S)-dihydroorotate, shikimate, 4-pyridoxate, 3-hydroxybenzyl alcohol, 2,5-dihydroxybenzoate, 3-hydroxybenzaldehyde, trans-cinnamate, estradiol-17α, deoxycholate, retinoate, oleic acid, and heptadecanoate were of analytical grade and from Sigma-Aldrich
Predicted absorption as ‘functional fingerprints’ of red cabbage and grape skin extracts were analysed by our liquid chromatography mass spectrometry (LC-MS) method with the application of the phytochemical absorption prediction (PCAP) model

Summary

Introduction

A phytochemical-rich diet is strongly associated with reducing the risk of chronic diseases including cancer [1], cardiovascular [2], and neurodegenerative diseases [3]. The health benefits of dietary phytochemicals have been attributed to their ability to mitigate oxidative stress and inflammation (OSI), which is associated with normal metabolism [4,5] but is involved in the onset of chronic diseases [6]. ROS can lead to OSI and unregulated OSI can result in molecular and cellular damage which in turn leads to an increased risk of chronic diseases [8]. Transient peaks or optimal steady state levels of ROS in the body are likely involved in maintaining good health and reducing the risk of disease [10]

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