Effects of N-acetylcysteine, oral glutathione (GSH) and a novel sublingual form of GSH on oxidative stress markers: A comparative crossover study.

Bernard Schmitt,Morgane Vicenzi,Catherine Garrel,Frédéric M Denis

doi:10.1016/j.redox.2015.07.012

Abstract

Glutathione (GSH) is critical to fight against oxidative stress. Its very low bioavailability limits the interest of a supplementation. The purpose of this study was to compare the bioavailability, the effect on oxidative stress markers and the safety of a new sublingual form of GSH with two commonly used dietary supplements, N-acetylcysteine (NAC) and oral GSH. The study was a three-week randomized crossover trial. 20 Volunteers with metabolic syndrome were enrolled. GSH levels and several oxidative stress markers were determined at different times during each 21-days period. Compared to oral GSH group, an increase of total and reduced GSH levels in plasma and a higher GSH/GSSG ratio (p=0.003) was observed in sublingual GSH group. After 3 weeks of administration, there was a significant increase of vitamin E level in plasma only in sublingual GSH group (0.83µmol/g; p=0.04). Our results demonstrate the superiority of a new sublingual form of GSH over the oral GSH form and NAC in terms of GSH supplementation.

Highlights

Glutathione (GSH) is an ubiquitous water-soluble molecule found in millimolar concentration in many tissues and cells
Our results demonstrate the superiority of a new sublingual form of GSH over the oral GSH form and NAC in terms of GSH supplementation
The comparative analysis of bioavailability between oral GSH and the sublingual form is summarized in Tables 3 and 4

Summary

Introduction

Glutathione (GSH) is an ubiquitous water-soluble molecule found in millimolar concentration in many tissues and cells. It is the most abundant intracellular low molecular weight peptide containing a thiol group. This thiol function is critical for the biological activity of GSH [1]. GSH is made from three amino acids: glycine, cysteine and glutamic acid. This tripeptide exists in reduced (GSH) and oxidized (GSSG) forms. The relative amounts of each form determine the cellular redox status (GSH/GSSG ratio) which is often used as a marker of antioxidative capacity of cells [2]

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