Download Miura, et al., 2001

TANNINS AND HUMAN HEALTH:
Nutraceuticals effect of Tannin and its
Monomers.
MAYANK TANDON & DR. S.N. RAI
Animal Nutrition Division,
National Dairy Research Institute,
e-mail: [email protected]
TANNINS
• Plant Tannins: distinctive group of polyphenolic
polymers of relatively high molecular weight
(M.W = 1000 to 20,000)
• Further categorized as: HYDROLYSABLE
tannins (HTs) or CONDENSED tannins (CTs or
Proanthocyandins) on the basis of their
structure and reactivity.
• HTs are of low M.W (500-3000) and are
polyesters of Gallic acid (gallo tannins) and
hexahydroxy-diphenic acid (ellagitannins)
with a central polyols such as sugars/glucose
and phenolic such as catechin.
• CTs, M.W (1900-28000) have no
carbohydrate core and comprise a group of
polyhydroxy-flavan-3-ol oligomers and
polymers linked by carbon-carbon bonds
between flavanol subunits.
TANNINS (Basic structure)
Hydrolysable Tannins
Condensed Tannins
Glucose
o
o
o
oH
o
oH oH
oH
oH
oH
oH
oH
oH
oo
o
o
oH
o
OH
Glucose
oH
oH
oH
OH
OH
Gallotannins
Ellagitannins
Catechin
• Cardiovascular disease, principally heart disease
and stroke, are the leading cause of mortality in
both men and women in all racial and ethnic
groups.
• The risk of atherosclerosis is increased by high
blood pressure, hypertension, kidney disorders,
obesity, diabetes, smoking, excessive alcohol
consumption, stress, thyroid and adrenal gland
problems, and lipid disorders
(Crespy and Williamson 2004)
• Tea contains many compounds, especially polyphenols and epidemiologically studies show that
polyphenolic compounds present in tea reduces
the risk of a variety of diseases.
• Catechins are the main compounds in green tea;
they consist of (-)-epicatechin, (-)-epicatechin-3gallate (ECg), (-)-epigallocatechin, (-)epigallocatechin-3-gallate (EGCg) etc.
(Graham, 1992)
• Monomers (catechin, epicatechin, gallic and
ellagic acid) of Tannin present in red wine/ green
tea improve the antioxidative / immune status of
the animals/ human.
(Percival et al., 2002)
• Epidemiological studies shows that poly-phenolic
compounds present in the Tea reduce the risk of
a variety of diseases.
THERAPEUTIC VALUES OF TANNIN METABOLITES
• Mice consumed wine rich in phenolic components
as catechin, epicatechin, gallic acid, ellagic acid
showed increased antioxidant activity.
• Gallic acid (GA) also showed strong antioxidant
activity by preventing lipid per-oxidation.
• GA is a strong antioxidant that possesses
antimutagenic and anticarcinogenic activities
(Shahrzad et. al., 2001)
• Green tea contains:
(+) – gallocatechin (GC),
(-)– epicatechin (EC),
(-)– epigallocatechin (EGC),
(-)– epicatechingallate (ECG),
(-)– epigallocatechingallate (EGCG)
which shows numerous biological activities
including antibacterial, antioxidant, anti-tumor and
cancer preventive activities.
• Catechin serve as powerful antioxidant against
lipid per oxidation when phospholipid bi-layers are
exposed to aqueous oxygen radicals.
• (+)Catechin prevents cancer (liver, lung,
breast and colon cancer) in at least one of
three ways:
First, they can prevent the formation of
carcinogens,
Second, they tone up the body's natural
detoxification defenses, and
Finally, they suppress cancer promotion.
• (+)Catechin has other promising qualities:
antibacterial and antiviral agent, regulating
cholesterol and blood pressure, and reducing
blood clotting tendencies that may cause
heart attacks or strokes
NEUTRACEUTICAL EFFECTS OF CATECHIN AND
EPICATECHIN
• Powerful Antioxidant effect – prevent lipid peroxidation
(Terao et al., 1994).
•
Antioxidant activity
Scavenge free radicals and reduce oxidative stress.
•
Enzyme induction and enhancing detoxification
glutathione peroxidase
catalase
superoxide dismutase
• Catechin and epicatechin have Super Oxide Dismutase
(SOD) like activity.
(Kim et al., 1995)
Cont…
• Prevent free radical induced RBC hemolysis.
(Zhang et al.,
1997)
• Prevent coronary artery disease.
(Ishikawa et al., 1997)
•
Inhibit the oxidation of LDL cholesterol, reduced
body fat and thereby decrease incidence of heart
disease.
• Catechins may stimulate the secretion of Bile
salts and the fecal excretion of cholesterol.
• EGCG inhibit phospholipid hydro peroxidation in
plasma.
• Catechin have an anti-hyperglycemic action
(Liu et al., 2005)
• Lowering blood glucose and normalizing insulin
release.
• Prevent cancer (Valcic et al, 1996) – prevent
formation of carcinogen, increase the body’s
detoxification
mechanism
against
tumor
inducing agents.
• Inhibition of Onco-gene expression
(Liu, 2004)
• Gallic acid occurs as a free molecule or as part of
a tannin molecule.
• GA is a strong antioxidant that possesses
antimutagenic and anticarcinogenic activities
(Shahrzad et. al., 2001)
Weight gain, food intake and liver weight of the rates
on control and powered green tea (PGT) treatments.
(Zhang, et al., 2002)
Measurement
No. of rats
Control
PGT (2 % in DM)
10
10
Initial body weight, g
166.9
167.0
Body wt. gain, g /d
68.6
79.0
Food intake, g /d
14.78
15.69
9.9
10.2
Liver weight, g /rat
6
5
5
4
4
control
3
PGT
2
1
mmol/ l
serum cholesterol level
mmol /l
Effect of dietary powered Green tea on serum cholesterol
level and Atherogenic Index (A) and on serum triglyceride
and lipid peroxide level (B). (Zhang, et al., 2002)
3
control
2
PGT
1
0
0
1
2
3
4
A
1. Total cholesterol m mol / l
2. HDL - Ch
3. VLDL + LDL - Ch
4. Atherogenic index
1
B
1. Serum triglyceride
2. Serum lipid peroxide
2
Plasma cholesterol, TG and oxidative state of plasma
lipoprotein in mice fed on atherogenic diet with and without
tea extract. (Miura, et al., 2001)
Particular
No of mice
Body weight, g
Plasma cholesterol,
m mol/ l
Plasma triglyceride,
m mol /l
Plasma lipid
peroxidase,
µmol MDA /l
Time
Control
Tea group
(3.2 mg /d)
0, wks
14
16
25.1
23.4
17
25.9
26.5
0, wks
14
0
14.6
83.2
0.89
14.6
75
0.86
14
0
8
0.49
6.48
30.3
0.85
8.63
20.0
Atheromatous area, aortic weights and aortic lipid contents in
mice fed an atherogenic diet with and without tea extract.
(Miura, et al., 2001)
Particulars
Control
Tea group % Reduction
Atheromatous area, %
36.1
27.7
23
Aorta, mg
14.3
11.0
23
Cholesterol, µmol / aorta
0.830
0.610
27
Triglycerides , µmol / aorta
0.137
0.068
50
Composition of Phenolic Compounds in Tea extract
(Miura, et al., 2001)
Catechins
Mg/ g
(-)Epigallocatechin-gallate (EGCg)
584
(-) Epigallocatechin (EGC)
117
(-) Epicatechin (EC)
66
(-)Gallocatechingallate (GCg)
16
(-)Epicatechin-gallate (ECg)
5
Caffeine.
4
Varying level of Potency among Catechins.
• A in vivo experiment indicated that the
components of tea catechins possess varying
inhibitory effects on Cu2+ - mediated oxidation of
LDL in the following order:
EGCg > ECg > EC > C > EGC
(Miura, et al., 1994 & 2001)
Catalase protein expression in rats at 16 wks of age that
consumed water (control), Black tea polyphenols, Green tea
polyphenols for 3 wks (Negishi, et al., 2004)
% intensity of catalase
expression
catalase
160
140
120
100
80
60
40
20
0
catalase
1
Control
2
BTP
3
GTP
Extract was having tea Polyphenols 5 g /l of water.
And water consumption was 30 ml /d
Catechin feeding effects on plasma TAS in rats
(pietta, et al., 1998)
Treatment
TAS (total antioxidant
status), m moles/ l
Control
1.5 ± 0.3
Catechin (2.1 g /l) 3.5 ± 0.3
Cu-Zn SOD (unites/ g)
Colon Cu-Zn SOD in rats given catechin
(pietta, et al., 1998)
3000
2500
2000
Control
1500
Catechin
1000
500
0
1
Composition of Phenolic Compounds in Muscadine
Wine
Mg/Liter
(Percival et al.,2002)
Muscadine Wine
Total Phenols
834
Gallic acid
14
Ellagic acid
8
Catechin
5
Epicatechin
22
B3 procyanidin
0.3
Total antioxidant capacity of plasma of mice
Absorbance at 405 nm
consuming red muscadine wine or ethanol
0.4
0.3
0.2
0.1
0
1
1 : Muscadine wine
2 : Ethanol
2
(Percival et al.,2002)
• Catechins hypothesized to help protect against
various diseases by contributing, along with
antioxidant vitamins (i.e. Vit. C & E) and enzymes
(i.e. SOD and Catalase)
• In vivo studies show that green tea catechins
increase total plasma antioxidant activity.
• Intake of Green tea extract also increases the
activity of SOD in serum and the expression of
catalase in the aorta.
• Malondialdehyde, marker of oxidative stress,
decreases after Green tea intake
• Catechins have a direct (antioxidant) or indirect
(increase of activity or expression) effect.
• Because catechins can act as antioxidant in vitro,
they might prevent the oxidation of other
antioxidants, such as vitamin E.
• In some cases ingestion of green tea catechins
does not modify the plasma status of vitamin E
and C in vivo
• Catechins increase vitamin E concentration in LDL
and in this way could protect LDL against
peroxidation.
Glucose concentration affected by Tannic acid
(Liu et al., 2005)
• In an oral Glucose tolerance test in rats, tea
catechins decreased plasma insulin levels but did
not affect plasma glucose levels.
• In type 2 diabetes, lipid metabolism is modified:
Plasma and Liver triglyceride levels and
plasma cholesterol levels are elevated, GTE intake
reduced these values in rats fed a sucrose-rich
diet.
• Catechins also reduced plasma TG levels.
• Tannic acid (TA) induces glucose transport
through activation of the Insulin-mediated
signaling pathways in adipocytes.
• TA inhibited the expression of key genes for
adipogenesis, and has an insulin-like glucose
transport stimulatory activity in adipocytes.
• Epigallocatechin gallate (EGCG) enhances oral
glucose tolerance in severely diabetic mice and
in moderately diabetic rats.
CONCLUSION
• Tannins & its monomers have profound effects
on health.
• Not advisable to take a large quantity of
tannins, as they may be toxic.
• It is important to determine the correct dosage
of tannins for promoting optimal health.