Biomolecules Responsible for the Total Antioxidant Capacity (TAC) of Human Plasma in Healthy and Cardiopathic Individuals: A Chemical Speciation Model.

Enrico Prenesti,Giorgio Bellomo,Marco Bagnati,Fabio Gosmaro,Silvia Berto

doi:10.3390/antiox10050656

Abstract

(1) Background: Much effort has been expended to investigate the antioxidant capacity of human plasma, attempting to clarify the roles of both metabolic and food substances in determining defenses against oxidative stress. The relationship between the total antioxidant capacity (TAC) and the concentrations of redox-active biomolecules in the human plasma of healthy and cardiopathic individuals was investigated in the present study to develop a chemical speciation model. (2) Methods: Plasma was collected from 85 blood donors and from 25 cardiovascular surgery patients. The TAC was measured using the CUPRAC-BCS (CUPric Reducing Antioxidant Capacity — Bathocuproinedisulfonic acid) method. Biomolecule concentrations were determined via visible spectrophotometry or HPLC/RP techniques. The relationship between the TAC and the concentrations was defined by applying a multiple regression analysis. The significance of the variables was first tested, and chemical models were proposed for the two datasets. The model equation is , where βi and [Ai] are the electronic exchange and the molar concentrations of the ith antioxidant component, respectively. (3) Results: The major contributions to the TAC, ~80%, come from endogenous compounds in both healthy and cardiopathic individuals, whereas the contributions from exogenous compounds were different between the two datasets. In particular, γ-tocopherol showed a different role in the chemical models developed for the two groups.

Highlights

As reported by recent reviews [1,2], much effort has been expended by scientists to investigate the antioxidant capacity of human plasma in the past two decades, in attempts to clarify the roles of both metabolic and food substances in determining defenses against oxidative stress
The dataset of healthy individuals was subjected to a statistical treatment to investigate the relationship between the total antioxidant capacity (TAC) quantity and the concentration of antioxidants
This investigation was preliminary to the assessment for the speciation model and aimed to identify those molecules that significantly contributed to the TAC definition

Summary

Introduction

As reported by recent reviews [1,2], much effort has been expended by scientists to investigate the antioxidant capacity of human plasma in the past two decades, in attempts to clarify the roles of both metabolic and food substances in determining defenses against oxidative stress. Oxidative stress is an undesirable condition caused by an imbalance between free radicals, commonly produced by aerobic metabolism, and scavenger biomolecules. Antioxidant Capacity (TAC) appears in the specialized literature and was previously widely discussed by the authors ([3] and references therein). TAC is conceived as a methoddependent quantity that provides information on the redox status of a fluid according to a simple measurement principles associated with a particular measuring apparatus. TAC has been measured in food, beverages, and body fluids according to various test protocols. Some papers [4,5,6] have shown an inverse correlation between

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