What Determines Total Antioxidant Capacity

Comparison of TAC of a biological material with the composition of antioxidants of this material and the reactivities of these antioxidants allows for estimation of the contribution of individual antioxidant species to the measured value of TAC. One should take into account that TEAC values of individual compounds may vary greatly depending on the method and conditions of the assay (Table 5). 

The most frequently studied clinically relevant material has been blood plasma. Although the estimated contributions of the main antioxidants obtained by different authors for various methods of assay differ to some extent, it is clear uric acid is the main determinant of TAC of human blood plasma (Table 6), the next being plasma protein (mainly thiol groups of the proteins). In deproteinized plasma, TAC showed a 99% correlation with urate (M14). It has been reported that about 30% of 

Relative Antioxidant Activities of Various Compounds with Respect to That of Trolox 

Compound Relative activity with respect to Trolox Method of measurement Ref. 

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