Introduction to Human Nutrition

222 Introduction to Human Nutrition

Repair

DNA repair enzymes

(Mg, Zn, folate, vitamin B

12

)

riboflavin, niacin and MSR

Amino acid andsugar products

Mitochondrial dysfunction

Mercapturic

acids

Alcohols

GSSG

GSSG

S-AAGSH

GST

Ferritin (Fe)

? FeCu

FeCu

PUFA peroxides

and radicalsPUFA alcohols

Vitamin E

Diet

Vitamin AVitamin ESeZnCuMnFeMgRiboflavinNicotinic acidFolateVitamin B

12

Lutein

Astaxanthin

Other Carotenoids

Phytic acidFlavonoidsIsoflavonoids

Other Phenols

Organo-sulfur compounds

Constituents of herbs and spices

S-AA

Vitamin C*

Vitamin E*

Vitamin C

NO

Energy

GR, glutathione reductase (EC1.6.4.2); GSH, reduced glutathione; GSH-Px glutathione peroxidase (EC1.11.1.9);

GSSG, oxidized glutathione;

GST, glutathione-S-transferase (EC 2.5.1.18); MSR, methionine sulfoxide reductase (EC1.8.4.5); PUFA, polyunsaturated fatty acid

s; S-AA,

sulfur amino acids; SH-proteins, sulfydryl proteins; SOD, superoxide dismutase (EC1.15.1.1); , transition metal-cataly

zed oxidant damage

to biomolecules.? Biological relevance.

ONOO



“Activated”

oxygen

“Activated”carotenoids

H

O 2

2

1 O

2

H^2

O

DienesEpoxides

Carbonyls

?

NADPH

Hexose

monophosphate

shunt(Mg)

Chain-breaking

(Also urate,SH-proteins,

bilirubin)Ubiquinol

α-Lipoic acidEstrogens

Lycopeneβ-carotene

NADP

GSH-Px

(Se)

GR

(riboflavin)

DNA and

protein damage

Preventive

and

scavenging

(also vitamin A)

HaptoglobinHemopexinTransferrin

Caeruloplasmin

(Cu)

Metallothionein

(Zn)SOD

(Cu, Mn)GSH-Px

(Se)

Catalase

(Fe)

Figure 9.8

Antioxidant defense system (from Strain and Benzie, 1999).