ABTS trapping

ABTS trapping capacity. 2,2 -Azinobis-3-ethyl-thiazoline-6-sulfonate. Useful under hydrophilic and lipophilic conditions ... 

Rhemrev et al. (RIM) measured TAC of human seminal plasma by ABTS + decoloration at 37°C and distinguished fast TRAP (decolorization measured 10 sec after addition of the sample) and slow TRAP (decolorization measured between 10 and 300 sec after addition of the sample). One of the compounds contributing to the slow TRAP is tyrosine, present in seminal plasma at high concentrations (Table 5). Another contributor to the slow TRAP is hypotaurine, but the contribution of tyrosine is more important due to its higher concentration in seminal plasma (2.12 mM vs. 36 /rM) (R14, V8). 

EDTA, Ethylenediaminetetraacetic acid TAS, total antioxidant status TRAP, total peroxyl-radical-trapping antioxidant capability of plasma ABAP, 2,2 -azobis(2-amidopropane) FRAP, ferric-reducing activity of plasma H2-DCF-DA, 2, 7 -dichlorofluorescein diacetate ORAC, oxygen-radical-absorbing capacity ABTS, 2,2 -azinobis(3-ethylbenzthiazoline-6-sulfonic acid). 

Kinetics of the reactions were followed by the use of the sodium salt of 2,2 -azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) as an easily oxidizable trap for the reactive higher valent iron-porphyrin intermediates and any radical products derived from YOOH (Y = alkyl or H). The one electron oxidation of ABTS provides ABTS-+ (Xmax = 660 nm). Regardless of whether YO-OH bond scission is homolytic (eqla) or heterolytic (eq2a), a... 

The products of the reaction of (l)Fe (X)2 with r-BuOOH in the absence of the trapping agent ABTS are (CH3)2C=0 (90%), CH3OH (90%), and r-BuOH (15%). Thus, 90% of t-BuOOH is converted to t-BuO-, which fragments to provide (CHs)2C=0 and CHs The rate constant for fragmentation of r-BuO radicals is appreciable in water ( = 1.4 X 10 s"l). With increasing [ABTS], the yields of (CH3)2C=0 and r-BuOH approach 15% and 84%, respectively. Thus, -75% of the t-BuO- intermediate cannot be trapped by ABTS, regardless of ABTS concentration. Moreover, the product yields are insensitive to... 

Scheme V) provides (CH3)2C=0 in 100% yield. Thus, only a mechanism involving homolytic 0-0 scission can explain the yields of products in the reaction of (1)F X)2 with t-BuOOH. Scheme VI accommodates these findings for the reactions of (l)Feni(X)2 and (2)Feni(X)2 with t-BuOOH. The fragmentation of r-BuO within the intimate pair for [(l)Feni(X)2t-BuO ] is proposed to account for the 15% of t-BuO- that cannot be trapped by ABTS. 

Com oil phenols have been studied with respect to their potential to scavenge the free radicals, the peroxyl radicals, the superoxide radicals, etc. The free radical scavenging activity of the phenolic acids using model free radicals such as l,7-diphenyl-2-picrylhydrazyl radical (DPPH ), or ABTS (2,2 -azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt cation radical) is often measured. TEAC (Trolox equivalent antioxidant capacity), FRAP (Ferric-reducing antioxidant capacity) and TRAP (total-radical-trapping antioxidant parameter) of the com oil are also used in order to obtain additional information, necessary to investigate the relation between the antioxidant intake and the oxidative stress related diseases (Stratil et al., 2008 Ceto et al., 2014 Apak et al., 2007). 

---