Chemistry Reference
In-Depth Information
Table 10.1 The one electron reduction potential (E
0
) of the radical form of reactive
oxygen species, phenolic antioxidants, carotenoids, and flavonoids
E
0
(mV) Ref. Compounds
E
0
(mV) Ref.
Compounds
H
2
O
2310
1
Uric acid
590
9
CH
3
CH
3
1900
1
pyrogallol
575
10
ROH (aliphatic alkoxyl
radical)
Catechin
570
7
1800
1
3,4-dihydroxyphenylalanine
(DOPA)
H
2
O
2
(HOO
·
, H
+
)
1060
1
570
7
-carotene in TX-100
1060
2
EC
570
9
Canthaxanthin in TX-100
1041
2
Gallic acid
560
11
Zeaxanthin in TX-100
1031
2
Methyl gallate
560
11
Astaxanthin in TX-100
1030
2
Sinapic acid
556
8
-carotene in TX-405/
TX-100
Chlorogenic acid
550
8
1028
2
ECG
550
9
ROOH (alkyl peroxyl
radical)
3,4-dihydroxylcinnamic acid
540
10
1000
1
Theaflavin digallate
540
12
Lycopene in TX-405/
TX-100
Caffeic acid
534
8
980
2
Catechol
530
1
Astaxanthin
970
3
4-Methylcatechin
520
6
Canthaxanthin
950
3
4-methylcatehol
520
11
H
2
O
2
(O
2
·ÿ
, 2H
+
)
940
1
Theaflavin
510
12
Glutathione
920
4
Taxifolin
500
5
Zeaxanthin
850
3
-tocopherol
500
1
-carotene
840
3
Trolox
480
1
Resorcinol
810
10
EGC
430
6
Kaempferol
750
5
EGCG
430
11
Hesperidin
720
6
Myricetin
360
5
Galangin
620
5
Fisetin
330
10
3,4-dihydroxylbenzoic acid
600
7
Quercetagetin
330
5
Luteolin
600
5
Quercetin
330
6
Morin
600
5
Ascorbic acid
282
1
PUFA (bis-allylic-H)
600
1
Fe(II) EDTA
120
1
Rutin
600
7
Fe(II) (aqueous)
110
1
o-Coumaric acid
596
8
Fe(II) citrate
100
1
Ferulic acid
595
8
Ubiquinone
ÿ36
1
b-coumaric acid
590
8
Dehydroascorbic acid
ÿ174
1
p-Coumaric acid
590
8
1. Buettner, 1993; 2. Burke et al., 2001; 3. Han et al., 2010; 4. Sharma and Buettner, 1993; 5.
Jovanovic and Simic, 2000; 6. Jovanovic et al., 1996; 7. Jovanovic et al., 1994; 8. Foley et al., 1999;
9. Luczaj and Skrzydlewska, 2005; 10. Rice-Evans and Packer, 2003; 11. Jovanovic et al., 1995; 12.
Jovanovic et al., 1997).
therefore do not efficiently abstract a hydrogen from unsaturated fatty acids
(Table 10.1, 2). Effective FRS also have FRS
·
that do not readily reactive with
triplet oxygen to form hydroperoxides. If a FRS forms a hydroperoxide, it could
decompose into higher energy free radicals species that could oxidize
unsaturated fatty acids (Liebler, 1993a).
Another way to look at the potential activity of antioxidants is through their
bond dissociation enthalpy, also called bond dissociation energy (BDE). BDE is
the standard enthalpy change when a chemical bond is broken by homolytic or
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