Unravelling the Photoprotection Capacity of Resveratrol on Histidine Oxidation

Jael R Neyra Recky,M Laura Dántola,Carolina Lorente

doi:10.3390/photochem1020012

Abstract

Exposure to sun radiation causes great oxidative stress and activates a numerous of defense mechanisms in living systems, such as the synthesis of antioxidants. Resveratrol (RSV), a naturally occurring stilbene molecule, has antioxidant properties and is synthesized in large amounts when plants are under high oxidative stress. Likewise, under UV and visible radiation, biomolecules are oxidized, losing their physiological properties and, therefore, avoiding the harmful effects of solar radiation is crucial in order to preserve the functionality of cellular components. In proteins, one essential component that is often susceptible to degradation is the amino acid histidine (His), which can be modified via several oxidizing mechanisms. In this article, we evaluate the photoprotection capacity of RSV in photosensitized oxidation of His, which is initiated with a one-electron transfer reaction, yielding the His radical cation (His•+). The photoprotective properties of RSV are evaluated using kinetics analysis during steady-state irradiation and laser flash photolysis experiments. The experimental results reveal that the presence of RSV in the solution causes an evident decrease of the His consumption initial rates as a result of a reaction between His•+ and RSV that recovers the amino acid. In addition, we conclude that during its antioxidant action, RSV is consumed being a sacrificial antioxidant.

Highlights

Interest in resveratrol (RSV) has grown steadily for about five decades, since it was discovered that it is synthesized in some plants in response to oxidative stress
RSV was classified as a phytoalexin, as it was evident that it is synthesized in response to stressful situations
The experiments were performed in air-equilibrated aqueous solutions at pH 4.5 and concentrations of His and Ptr were determined by High-Performance Liquid Chromatography (HPLC) at each irradiation time

Summary

Introduction

Interest in resveratrol (RSV) has grown steadily for about five decades, since it was discovered that it is synthesized in some plants in response to oxidative stress. RSV was classified as a phytoalexin, as it was evident that it is synthesized in response to stressful situations. Phytoalexins are a family of chemically unrelated molecules, which are found in plants and involved in their defense reactions during a variety of injuries [2]. When classifying this family of compounds according to their chemical structure, a subgroup of stilbenes was included, having a common structure of two aromatic rings joined by a methylene bridge. RSV has been found in more than 70 plant species, including edible fruits and vegetables (grapes, cranberries, peanuts, cocoa) [3]

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Conclusion