New Findings on antioxidants

1
Taiwan NuSkin presentation Medical
Symposium November 3, 2007
New Findings on antioxidants Super
Antioxidants
Prof. Lester Packer

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US
Western countries
Asian countries
China
Int.J. Cancer (2000) 8560-7
Courtesy Emily Ho
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4
Cross Cultural Study of Heart Disease
Mortality
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Oxidative Stress

• Free radicals cause oxidative stress
• Leads to tissue damage, aging and disease

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Oxidative Stress Damage vs. Repair Adaptive
Signaling
ROS formation Redox Signaling
Apoptotic Signaling
Necrosis
Oxidant induced cell signaling and damage
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Oxidative Stress
An imbalance between oxidants and antioxidants
in favor of the oxidants, leading to a disruption
of redox signaling and control and/or molecular
damage.
Jones, D.P. Redefining oxidative stress.
Antioxid. Redox Signal. 2006, 8 1865-1879.
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Glutathione is the cells major antioxidant
Oxidative Stress can be estimated from the ratio
of reduced to oxidized antioxidants
GSH reduced
GSSG oxidized
Gluthathione Peroxidase
Gluthathione Reductase
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Ratio of GSH/GSSG becomes progressively oxidized
during the life cycle of cells
Redox State -(SH)2-SS-
Proliferation
1001
-
250
-
250
Eh, mV
101
Differentiation
11
-
200
-
200
Apoptosis
110
-
150
-
150
Kirlin WG, Cai J, Thompson SA, Diaz D, Kavanagh
TJ, Jones DP. Glutathione redox potential in
response to differentiation and enzyme
inducers.Free Radic Biol Med. 1999
Dec27(11-12)1208-18.
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Jones D.P., Antioxid Redox Signal. 2006
Sep-Oct8(9-10)1865-79.
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Antioxidants
Redox

• Vitamins C and E
• Polyphenols (Flavonoids)
• Low molecular weight thiols
• Cysteine, Methionine, Glutathione, R-? Lipoic
  Acid,
• Co-enzyme Q
• L-Carnitine

Radical Scavenging

• Carotenoids

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The Antioxidant Network in Membranes
Oxygen Metabolism
Water Soluble
Lipid Free Radicals LOO LO
Fat Soluble
Vit. C cycle
Water Soluble
Metabolism
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Inducers Of Phase 2 enzymes and proteins
The capacity of these compounds to induce the
phase 2 response depends upon their ability or
that of their metabolites to react with thiol
groups, a property shared with all other classes
of phase 2 inducers, which show few other
structural similarities
Dinkova-Kostova, A.T., Holtzclaw, W.D., Cole,
R.N., Itoh, K., Wakabayashi, N., Katoh, Y.,
Yamamoto, M., Talalay, P., PNAS USA,
99(18)11908-13, 2002. Fahey JW, Stephenson KK,
Dinkova-Kostova AT, Egner PA, Kensler TW, Talalay
P. Carcinogenesis 2005 Jul26(7)1247-55
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Inducers of Nrf2 transcription, the phase II
response, all have in common the ability to react
with suphydryl groups
Polyphenols Bioflavanoids Chlorophyll Carotenoids
Heme, H2O2, NO? Carotenoid oxidation products
Chemicals reacting with Sulphydryl groups, e.g.,
Isothioyonates (sulforaphane), Dithiolanes,
1,2-dithiol-3-thiones, a-Lipoic acid
Nrf2-Keap-1system (ARE/EpRE)
Alkyl and Aryl Halides, Metal Ions, e.g., HgCl2,
CdCl2
HO-l
?GCL GSH increases
NAD(P)H-Quinone reductase, Ferritin, Epoxide
hydrolase GSH, Gluconic acid,methyl and other
transferases
Mn Superoxide Dismutase Thioredoxin, Trx
reductase Mitochondrial and other Antioxidant
enzymes
Antioxidant Defense, Detoxification,
Chemoprevention
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Carotenoids in Humans are

• Vitamin A precursors
• cyclic hydrocarbon carotenoids

• Free radical scavengers
• protect against oxidation

• Inducers of enzymes proteins
• needed for antioxidant defense

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Carotenoids in fruits vegetables
Carotenoids in Human Plasma
Lycopene (20-40)
b -carotene (15-30)
a-carotene (5-10)
ß-cryptoxanthin (13-20)
Spinach, Green peas, Green Beans , Lima Beans
Broccoli, Brussel sprouts, Cabbage, kale, Kiwi,
Lettuce Carrots, Pumpkin, Sweet Potatoes,
Apricots, Cantaloupe, Watermelon Tomatoes, Pink
Grapefruit
Lutein (10-20)
Zeaxanthin (1-5)
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Raman ScatteringSir C. V. Raman, Nobel Prize in
Physics 1930
Carotenoids shift blue laser light to green from
473 nm to 510 nm
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Raman scattering studies are used to measure
carotenoids in the Eye and to diagnose
age-related macular degeneration
Lutein Zeoxanthin
Macula
Gellermann W, Ermakov IV, McClane RW, Bernstein
PS. Raman imaging of human macular pigments.
Optics Letters. 200227833
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Lifestyle affects raman scattering intensity
Skin Raman Intensity (2005 US data of 209,628
Non-Supplement Users)
35000
31507
30000
29704
26639
25000
plt0.01
plt0.01
plt0.01
24793
20000
Std. Error 38
Std. Error 61
Std. Error 106
Std. Error 44
15000
Courtesy Stephen Poole, Pharmanex
10000
1 or less
2 to 3
4 to 5
6 or more
Daily servings of fruits and vegetables
Skin Raman Intensity (n 372)
60000
40000
r 0.84 (plt0.0001)
20000
C. Smidt and D.S. Burke, Nutritional Significance
and Measurement of Carotenoids, Current Topics in
Nutraceutical Research 2004, 2, 79-91
0
0
0.5
1
1.5
2
2.5
3
3.5
4
Total Serum Carotenoids (µg/ml)
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Carotenoids in human supplements equivalent
to amounts in food (courtesy KJ Yuem)
4 mg Lycopene
4 mg b-Carotene
4 mg Lutein
1 1/3 medium carrots or ¼ cup pumpkin
1 medium tomato or ¾ Tsp tomato paste
¼ cup of cooked spinach
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Plasma Carotenoid Concentration Is increased
after Supplementation
180
Placebo
Mixed Car
160
Lutein
b-Carotene
140
Lycopene
120
100
Plasma Total Carotenoid (mg/dL)
80
60
40
20
0
D1
D15
D29
D43
D57
Time, Day
Significantly different from baseline plt0.05
Courtesy KJ Yuem, et al.
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Carotenoid Supplementation protects DNA Damage of
human lymphocytes The comet assay
Day 57
Courtesy KJ Yuem, et al.
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Carotenoid Supplementation protects DNA damage
in human lymphocytes
Comet tail factor ratio compared with day 1
Placebo
1.6
1.4
1.2
1.0
0.8
0.6
0.4
(D1/D1)
(D15/D1)
(D29/D1)
(D43/D1)
(D57/D1)
Closed symbols indicate significant differences
from Placebo group (plt0.05)
Courtesy KJ Yuem, et al.
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• Physiological doses of a ß-carotene, lycopene,
  lutein or a mixture of these carotenoids protect
  against endogenous or hydrogen peroxide (H2O2 )
  induced DNA damage in white human blood cell
  lymphocytes

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Genes effected by carotenoids in lung tissue of
cigaraette exposed exposed mice
Nrf2 Transcription
Inflammatory and immune responses
Metabolism and Ion channels
Receptors
Growth factors
Apoptosis
Unknown Genes
Others
Control diet
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Genes Up or down regulated
0
-20
?-carotene
20
0
-20
Lycopene
20
0
-20
Lutein
20
0
-20
Mixed 3-Carotenoids
20
0
-20
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Gene chip studies show carotenoids

• have specific effects on gene expression
• effect expression of genes for transcription
  factors which enhance
  the biosynthesis of antioxidant enzymes and
  proteins
• modify genes affecting xenobiotic metabolism
  and immune system response

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Vitamin A levels are increased in healthy
centenarians compared to younger subjects
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153 Italian centenarians, p lt 0.0001
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4



Vitamin A (µM)
3
2
1
0
Centenarians
60-79 yrs
80-99 yrs
lt 60 yrs
Christina Polidori, Eur J Clin Nutr 2007
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Super Antioxidants

• Substances in plant fruits and vegetables have a
  wide range of different molecular structures.
  Some like bioflavonoids are powerful direct free
  radical scavengers.
• These and other small molecules also can induce
  the biosynthesis of antioxidants.
• These are bifunctional antioxidants or Super
  Antioxidants
• because they
• scavenge free radicals directly and immediately
• but also act indirectly by inducing genes and
  thus have long lasting effects