Positive Effects of Green Tea on Hepatic functional, Histological
and Ultrastructural Changes of Hepatocyte Induced by High
Sucrose Diet in Albino Rats.
Abeer A. Shoman , Noha I. Hussien and Ayman M. Mousa*
Departments of Physiology and Histology*
Faculty of Medicine, Benha University, Egypt.
Abstract
Introduction: High sucrose diet has various effects on hepatic function. In addition the
obese persons are susceptible to develop fatty liver disease (FLD). Green tea contains
powerful antioxidants, polyphenols, which help to remove free radicals from your body's
cells. There is a little information about the effects of green tea extract on liver function
and histolological changes in the liver of obese rats.
Aim of the study: The objective of this study was to assess the effects of high sucrose diet
on body mass index, serum lipid profile, blood glucose, aspartate aminotransferase (AST),
alanine aminotransferase (ALT) level and liver histology (light microscope using H&E;
toluidine blue& transmission electron microscope) in rats and the role of green tea extract
in minimizing these changes.
Materials and Methods: The rats included in this study were classified into 4 main groups;
group I: control group received standard diet, group II: rats received standard diet and
green tea, group III: High Sucrose rats, group IV: high Sucrose group received green tea
extract.
Results: High sucrose diet group caused significant changes in the histology of liver where
fatty infiltration is prominent in most hepatocytes while the remaining cells exhibited
vacuolated cytoplasm with pyknotic nuclei. Ultra structurally, the most characteristic
features observed in most hepatocytes were accumulation of fat droplets and the
degenerative changes especially in mitochondria. Biochemically there was a significant
increase in serum triglycerides, total cholesterol ,LDL.C, blood glucose, aspartate
aminotransferase (AST) and alanine aminotransferase (ALT) as well as a significant decrease
in serum HDL.C. All these histological & biochemical effects were improved by green tea.
Conclusion: From this study we can conclude that, high sucrose diet caused significant
changes in histological structure of the liver with a significant increase in body mass index,
serum triglycerides, total cholesterol, LDL, blood glucose, aspartate aminotransferase (AST)
and alanine aminotransferase (ALT) as well as a significant decrease in serum HDL. All these
effects were counteracted by green tea consumption.
Key Words: obesity, green tea, hepatocyte, albino rats.
 www.bu.edu.eg.
1
Introduction
Nonalcoholic fatty liver disease (NAFLD) covers a spectrum of liver disease ranging from
simple hepatic steatosis (accumulation of triglyceride inside hepatocytes) to nonalcoholic
steatohepatitis (necrosis and inflammation), with some people ultimately progressing to liver
cirrhosis and failure. The prevalence of nonalcoholic fatty liver disease (NAFLD) is high and
linked to obesity, diabetes mellitus, and hypertriglyceridemia (1).
High-fat and high-sucrose (HS) intakes were shown to contribute to syndromes such as
hyperlipidemia, glucose intolerance, hypertension, and atherosclerosis (2, 3).
Green tea is a rich source of polyphenol catechins. Epigallocatechin gallate (EGCG) is the
most active form of the catechins responsible for green tea’s antioxidant, anti-inflammatory,
and metabolic effects. Green tea also contains caffeine, which appears to act synergistically
with EGCG to assist metabolism (4).
Some studies show that substances in green tea may offer several weight-loss-promoting
effects, such as speeding up your metabolism and suppressing your appetite (5).
Consumption of green tea may enhance health because it reduces the incidence of cancer in
various experimental models, is a potent antioxidant, and modulates serum cholesterol
concentrations (6). Long-term consumption of green tea may decrease the incidence of
obesity and, perhaps, green tea components such as EGCG may be useful for treating obesity
(7). Dietary green tea extracts alleviated body weight gain and insulin resistance in diabetic
and high-fat mice, thus ameliorating glucose intolerance (8).
Green tea may help your liver -- or it may not, depending on how you consume it and in
what quantities. While drinking a moderate amount of green tea may reduce the risk of liver
cancer and other liver disorders, taking large amounts of green tea supplements could have
toxic effects on your liver (9). Hepatoprotective effects of green tea against carbon
tetrachloride, cholestasis and alcohol induced liver fibrosis were reported in many studies.
Green tea may protect liver cells and reduce the deposition of collagen fibers in the liver.
Green tea provides a safe and effective strategy for improving hepatic fibrosis (10).
The use of green tea extract appeared to be beneficial to rats in reducing lipid peroxidation
products. These results support and substantiate traditional consumption of green tea as
protection against lipid peroxidation in the liver, blood serum, and central nervous tissue
(11).
Green tea, is a known cancer fighter, but it also has liver-protective properties. The catechins
in green tea are powerful antioxidants that seem to protect against the damage that toxins
wreak upon cells. Various animal studies indicate that green tea is helpful in the treatment
of viral hepatitis and liver cancer. It has been found to reduce and prevent the growth of
abnormal liver tissue in rodents (12).
Besides an obesogenic environment and reduced energy expenditure during work and less
activities, one of the primary causes of the current epidemic of obesity and related
metabolic disorders is related to the western-style diet, which includes excessive intake of
high-fat and high-sucrose foods. Several studies have assessed the long-term (over
2
10 weeks ~ 2 years) effects of high-fat and/or high-sucrose diets on metabolic risk factors
(13). The rapid onset of hepatosteatosis, adipose tissue hypertrophy and hyperinsulinemia
by ingestion of a diet high in fat and sucrose may possibly be due to the rapid response of
lipogenic, insulin signalling and inflammatory genes (14).
The aim of our study is to investigate the effect of high sucrose diet in deterioration of liver
structure and function and the role of green tea in these changes in male albino rats.
Material and methods
Animals
This study was carried in department of physiology, Benha faculty of medicine, where the
animals were housed for the entire experimental period. Eight-week-old male rat were
housed in a room at average temperature with a normal light–dark cycle.
Diets:
Standard chow diet: In this type of diet
- The fat represented 3.73% of the total caloric requirement.
- The carbohydrates represented 43.88% carbohydrate (40.75% starch and 3.13% sucrose)
of the total caloric requirement.
- The protein represented 23.54% of the total caloric requirement (15).
High sucrose diet:
The fat represented 6.40% of the total caloric requirement.
- The carbohydrates 49.85% (4.5% starch and 47.35% sucrose) of the total caloric
requirement.
- The protein represented 23.60% of the total caloric requirement.
- The fibers represent 9.15% of the total caloric requirement.
- The high-sucrose diet was obtained mixing 600 g sucrose and 60 g of soy oil to 1000 g of a
previously triturated standard chow for four weeks. Casein was added to achieve the same
protein content as the standard chow (16).
Green Tea Extract Administration:
Rats received 300 mg/kg bwt. green tea extract (GTE) [Multi –treat Arab Co. for
Pharmaceutical & Medicinal plants (MEPACO- MEDIFOOD) Enahas El Rami- Sharkeya- Egypt,
each tablet contains 300 mg green tea dry extract, (30% polyphenols)] in 1 ml distilled
water/ rat by gavages daily for 14 weeks. In our present study we chose to use a moderate
dose of green tea extract (GTE) to avoid adverse effects of GTE on many body organs, as
there were evidence of deleterious effects of high doses of GTE including treatment-related
mortality occurred in male and female mice receiving1000 mg/kgbwt. Treatment dose which
was likely related to liver necrosis, while using doses not exceeding 500 mg/kgbwt.showed
no adverse effects in males and females of both species sexes (17). Humane care for rats was
provided according to the guidelines of the National Institutes of Health (NIH) of animal Care
and the local committee approved this study. All animals survived till the end of the
experiment.
3
Experimental protocol
The animals had free access to water and standard mouse chow for an acclimatization
period of 1 week. Thereafter, animals weighing 200-225 g were randomly assigned to four
groups for the feeding experiment. The control Group I: (n = 10) was fed standard mouse
chow, the green tea Group II: (n = 10) was fed standard mouse chow with green tea by
gavages', group III the HS Group (n = 10) was fed the diet which was high in sucrose and
Group IV: (n = 10) was fed the diet which was high in sucrose and received green tea by
gavages'. Body weight and food intake were monitored throughout the study. At the end of
the experiment, all rats were anesthetized using diethyl ether inhalation, the body weight
and body length were used to confirm the obesity through the obesity parameters body
mass index (body weight g/ length cm2).
Blood samples were collected by intracardiac suction for biochemical analysis, Whole blood
was collected into tubes, and serum was obtained by centrifugation at 3000 rpm for 15 min at
4 °C and stored at −80 °C until biochemical analysis. The determination of the activity of
hepatic transaminases AST and ALT, glucose, triglyceride, total cholesterol, LDL, HDL and
albumin were determined enzymatically using commercially available reagent kits in benha
biochemistry analysis unit.
A histological study was performed following a midline laparotomy to remove the liver. The
liver was dissected and fixed in 10% formalin solution at room temperature. An experienced
pathologist evaluated all samples Liver portions were fixed in 10% formalin for histological
examination.
Statistical Analysis
All data were expressed as mean  S.D; data were evaluated by the one way analysis of
variance. The calculations were performed by SPSS program version 17. Difference between
groups were compared by Student's t-test with P  0.05 selected as the level of statistical
significance.
Results
Body weight index (BWI)
Mice in the HS diet group gained weight rapidly. As shown in table (1) and Fig.1 the HS diet in
group II (Hs) increased the body weight (P < 0.01), compared with the control group fed
standard chow diet. Green tea administration had no significant decrease in body weight
index in group II (standard diet & green tea)=Gt while, it significantly decreased BWI in
group IV (high sucrose diet & green tea )=Hs Gt.
Table (1)
Group
BWI (g/cm2)
Control
0.527+0.030
Gt
HS
0.545+0.03
0.818+0.05*
Hs Gt
0.61+0.015#
*Significant changes compared with the control group
# Significant changes compared with the Hs group
Plasma lipids profile and blood glucose
As shown in table (2), the HS diet increased total cholesterol, LDL–C, triglyceride
(P < 0.001)& HDL–C was decreased (P < 0.01) as compared with the control group.
Green tea consumption decreased total cholesterol, LDL–C, triglycerides (P < 0.01).
HDL–C was increased (P < 0.01) as compared with (HS group).
4
Table (2): Lipid profile (Triglycerides, Total cholesterol, and HDL.C and LDL.C
mg/dl). Results are expressed as the Mean ± SE.
Control
Gt
HS
HS Gt
*
Trigylc. (mg/dl)
86+2.5-64
92+1.73
144+2.04
87.8+0.86#
T. choles.(mg/dl) 8 89+ 1.59
80+1.78
151+0.97*
92+1.34 #
LDL(mg/dl)
18+ 1.69
17+1.63
19+0.56 *
41+1.377#
HDL (mg/dl)
55 +1.32
56+1.72
35+1.426*
58.8+0.71#
*Significant changes compared with the control group
#
Significant changes compared with the Hs group
Plasma glucose, ALT and AST levels
As shown in table (3), The HS diet significantly increased blood glucose, ALT and AST
level (P<0.01) in group (III). Green tea consumption in group (IV) caused significant
decrease of blood glucose, ALT and AST (P<0.01), as compared with the Hs group.
Table (3): Serum glucose, ALT, AST. Results are expressed as the Mean ± SE.
Control gp.
Glucose (mg/dl) 101+1.52
AST(u/l)
156.25+1.26
ALT(u/l)
43.75+1.12
Gt gp.
108+1.43
149.28+1.55
47.24+0.69
HS gp.
160+2.23*
254.29+5.05*
65+0.57*
HS Gt gp.
110+0.701#
152.78+2.16#
39.85+1.23#
*Significant changes compared with the control group
#
Significant changes compared with the Hs group
Histopathological study
Group 1 (control group):
The histological appearance of the liver in the control group was normal. Light microscopic
examination of the liver of control rat group stained by H&E showed the normal
characteristic hepatic architecture. The hexagonal hepatic lobules were formed of
hepatocytes arranged in cords radiating from the central veins. The hepatocytes appeared
polyhydral in shape with large rounded or oval nuclei and sometime it contained two nuclei.
The hepatic sinusoids were seen as narrow spaces in-between the hepatic cords (Fig. 1).
The hepatocytes stained by toluidine blue appeared polyhydral in shape with large rounded
or oval nuclei and enclosed thin walled blood sinusoids (Fig. 2).Ultrastructural examination
of the liver specimen sections of this group showed normal polygonal hepatocytes with
rounded or oval nuclei that had regular nuclear membrane, prominent nucleolus and clumps
of chromatin(Fig.3). The cytoplasm showed different cell organelles. The mitochondria
appeared rounded or elongated and had a homogenous matrix of moderate electron
density. The rough endoplasmic reticulum appeared in the form of a group of flattened
cisternae and commonly located in the perinuclear regions. Lysosomes appeared as
heterogeneous organelles with extremely electron- dense matrix (Fig. 3).
5
Fig (1) A photomicrograph of a section in the liver of an adult rat from G1 (control group) Showing a central
vein (V) with radially arranged hepatocytes (H) & blood sinusoids (S) in between them. The hepatocytes
appears polyhydral in shape with large rounded or oval nuclei and acidophilic cytoplasm. (H&E X 630).
Fig (2) A photomicrograph of a semithin section in the liver of an adult rat from G1 (control group) showing a
group of hepatocytes arranged in cords radiating from a central vein (cv). The hepatocytes appeared polyhydral
in shape with large rounded or oval nuclei (n) and sometime it contained two nuclei(2 n).The hepatic blood
sinusoids (s) were seen as narrow spaces inbetween the hepatic cords. (Toluidine Blue X l000).
Fig (3) An electron micrograph of ultrathin section in the liver of an adult rat from G1 (control group) showing a
part of normal hepatocyte with oval nucleus that has regular nuclear membrane, prominent nucleolus (N) and
clumps of chromatin. The mitochondria (M) appears rounded or elongated with a homogenous matrix of
moderate electron density while many free scattered glycogen particles (G) are seen inside the cytoplasm . The
rough endoplasmic reticulum (rER) appears as a groups of flattened cisternae near the perinuclear regions and
lysosomes have a heterogeneous electron- dense matrix (Ly). (Uranyl acetate and lead citrate X 6000).
6
Group 2( non obese green tea received group):
Light microscopic examination of the liver in group 2,stained by H&E showed the normal
characteristic hepatic architecture. The hexagonal hepatic lobules were formed of
hepatocytes arranged in cords radiating from the central veins (Fig.4).
Fig. (4): a section in the liver of an adult rat from G2 (non obese green tea receiving rats) Showing a central vein
with radially arranged hepatocytes & blood sinusoids inbetween them. The hepatocytes appear polyhydral in
shape with large rounded or oval nuclei and acidophilic cytoplasm.
Group 3 (obese high sucrose diet group):
Examination of the liver sections of group (3) stained with H&E by the light microscope
revealed a congested central vein & hepatic sinusoids by the blood elements surrounded by
affected hepatocytes with multiple changes in their shapes. Many hepatocytes appeared
polyhydral with large oval nuclei that showed a signet ring appearance and cytoplasmic lipid
infiltration. Some hepatocytes had vacuolated cytoplasm and deeply stained nuclei. (Fig. 5)
Many hepatocytes stained with toluidine blue appeared polyhydral in shape with large oval
nuclei that showed a signet ring appearance and infiltration by many cytoplasmic lipid
droplets allover the cytoplasm (Fig.6).
Electron microscopic examination of group 2 showed hepatocytes with many vacuoles and
multiple small lipid droplets that appeared as electron-lucent areas allover the cytoplasm.
Some mitochondria appeared normal while others were degenerated. The indentation in the
nuclear envelop was demonstrated with heterogeneous distribution of the nucleoplasm . the
cytoplasm also includes some lysosomes and small amount of rough endoplasmic reticulum
(Fig 7).
7
Fig (5) A photomicrograph of a section in the liver of an adult rat group 3 showing a central vein (CV)
surrounded by affected hepatocytes with multiple changes in their shape. There are areas of lipid infiltration
(L) and a signet ring appearance in the cytoplasm of hepatocytes while some hepatocytes have vacuolated
cytoplasm (V) due to massive areas of degeneration with deeply stained nuclei. Moreover some areas revealed
loss of hepatic architecture with dilatation and congestion of the blood sinusoids (s). (H&E X 630).
Fig (6) A photomicrograph of a semithin section in the liver of an adult rat group 3 showing many polyhydral
hepatocytes with large oval nuclei that showes a signet ring appearance and infiltration by multiple small lipid
droplets (L) allover the cytoplasm. A group of irregular hepatocytes appears with oval nuclei (N) and many
vacuoles (v) in their cytoplasm. The blood sinusoids (s) have blood elements.(Toluidine Blue X l000).
Fig (7) An electron micrograph of a hepatocyte of an adult rat group 3 showing a multiple small lipid droplets
(L) all over the cytoplasm, polymorphic degenerated mitochondria (M) , some lysosomes and little rough
endoplasmic reticulum (rER). The nucleus (N) has an irregular indented envelop by three lipid droplets (Uranyl
acetate and lead citrate X 6000)
8
Group 4 ( High sucrose, green tea received group) :
Light microscopic examination of a section in the liver of the adult rat group 4 stained by
H&E clarified that, the liver tissue appeared more or less similar to the control group. The
central vein was surrounded by cords of relatively normal hepatocytes and mild congestion
of the hepatic blood sinusoids. Some hepatocytes were binucleated while others still had a
vacuolated foamy cytoplasm with small dark nuclei, (Fig.8).The semithin section in the liver
of the adult rat group 3 stained by toluidine blue showed a group of polyhedral hepatocytes
with rounded nuclei (N). Their cytoplasm had some lipid droplets(L) and the blood sinusoids
(s) appeared slightly congested with blood elements (Fig.9).Ultrstructural examination of
this group showed a relative improvement, where some hepatocytes had euchromatic nuclei
and a prominent nucleoli. Their cytoplasm contained a mitochondria,rough endoplasmic
reticulum, numerous glycogen granules and few vacuolization. binucleated hepatocyte with
euchromatic nuclei (mitotic figures) could also be observed (Fig. 10).
Fig (8) A photomicrograph of a section in the liver of an adult rat group 4 Showing a central vein (CV) with
radially arranged relatively normal hepatocytes (H) and foamy appearance of some hepatocytes (L). Some
hepatocytes have vacuolated cytoplasm(V) and small dark nuclei and mild congestion of the hepatic blood
sinusoids (S) in between them. (H&E X 400).
Fig (9) A photomicrograph of a semithin section in the liver of an adult rat group 4 showing a group of
polyhedral hepatocytes with rounded nuclei (N), the cytoplasm contains numerous glycogen granules(G) and
some lipid droplets (L) .The blood sinusoids (S) appears slightly congested with blood elements. (Toludine Blue
X l 000).
9
Fig (10): An electron micrograph of ultrathin section in a hepatocyte of an adult rat group 4 showing a rounded
nucleus with nucleolus (Nu) , heterochromatin and euchromatin . The cytoplasm has mitochondria (M), rough
endoplasmic reticulum (rER) , lysosomes with heterogeneous electron- dense matrix (Ly), some lipid droplets
(L), and free scattered glycogen granules (G). (Uranyl acetate and lead citrate X 6000).
Discussion
In our study, we demonstrated that feeding of the HS diet caused gains in body weight and
hepatic steatosis after 4 weeks. Thus, rapid onset of visceral obesity and fatty liver may occur
with intake of a high-calorie diet that is high in fat and sucrose. These results were in agreement
with (18) as they found that dietary fructose, but not glucose, increased de novo lipogenesis and
promoted dyslipidemia, decreased insulin sensitivity, and increased visceral adiposity in
overweight/obese adults .In addition Nagata R and colleagues revealed that adult male SpragueDawley rats fed a sucrose-rich diet (70% sucrose) for 2–3 wk that developed fatty livers and
became obese. In addition they suggested that fructose, not glucose, is the primary cause of
hepatic changes after chronic ingestion of a high-sucrose diet; diets enriched with a comparable
amount of glucose, instead of sucrose or fructose, do not produce any overt hepatic
abnormality. This finding may be mainly attributable to the unique metabolic properties of
fructose, i.e. its rapid uptake by the liver and its entry into the glycolysis pathway after
bypassing the phosphofructokinase regulatory step (19).
Our study revealed that green tea leads to significant decrease in the body weight index of rats.
As well as significant decrease in the serum levels of glucose, ALT, AST, triglycerides, total
cholesterol and LDL.C. With significant increase in serum level of HDL.C. These results were in
agreement with (20) as they suggested that Green tea significantly decreased the BWI in high
sucrose obese rats as green tea extract may boost metabolism and help burn fat.
Diet-induced obesity is largely caused by disorders of fat metabolism, resulting in a massive
accumulation of fat in various tissues. Lipid and energy metabolism are regulated by a complex
network of signaling processes, and therefore investigated mRNA expression of key genes
regulating lipid metabolism, The HF–HS diet upregulated liver LPL mRNA expression. The lipolytic
enzyme LPL mediates uptake of circulating lipid into peripheral organs, and it is the primary
enzyme responsible for chylomicron- and very low–density lipoprotein–triglyceride lipolysis (21).
Bioactive ingredients of green tea extract caused in the liver an increase in the activity of
glutathione peroxidase and glutathione reductase and in the content of reduced glutathione as
well as marked decrease in lipid hydroperoxides (LOOH), 4-hydroksynonenal (4-HNE) and
malondialdehyde (MDA).The use of green tea extract appeared to be beneficial to rats in
reducing lipid peroxidation products. These results support and substantiate traditional
10
consumption of green tea as protection against lipid peroxidation in the liver, blood serum, and
central nervous tissue (22).
In our results there was histological and ultastructural changes in obese high sucrose rat liver
include degeneration and disruption of the hepatocytes, degeneration of the cells lining the bile
ducts and occlusion of the central portal vein. Green tea consumption had greatly improved the
hepatic structure and function. The liver dysfunction in obese rats where the serum liver
enzymes (ALT &AST) increased was greatly normalized after green tea administration. In
addition; there was a biochemical change as increased plasma triglycerides, total cholesterol, and
LDL level and blood glucose in obese group and these changes became normal in green tea
received obese rats. These results were in agreement with (23) as they showed that, the
triglyceride content in the liver as well as the cholesterol content in the heart of rats fed sucroserich diet were elevated and were normalized by all types of tea drink tested. Although green and
oolong tea extracts contained similar composition of catechin, their findings suggest green tea
exerted greater antihyperlipidemic effect than oolong tea. Apparent fat absorption may be one
of the mechanisms by which green tea reduced hyperlipidemia as well as fat storage in the liver
and heart of rats consumed sucrose-rich diet.
Green tea contained very large amounts of catechins (173.1 mg/dl), including epigallocatechin
gallate (61.8 mg/dl), which have potent antioxidant effects, in addition; Green tea contains 2% to
4% caffeine, and Unlike black tea, green tea also contained ascorbic acid (3.0 mg/dl) and may
reduce the risk of liver cancer (24).
Eight studies showed a significant protective role of green tea against various liver diseases four
studies showed a positive correlation between green tea intake and attenuation of liver disease.
Moreover, the other two studies also presented the protective tendency of green tea against
liver disease (25). Research shows that green tea lowers total cholesterol and raises HDL ("good")
cholesterol in both animals and people. One population-based clinical study found that men who
drink green tea are more likely to have lower total cholesterol than those who do not drink green
tea. Green tea also seems to protect the liver from the damaging effects of toxic substances such
as alcohol. Animal studies have shown that green tea helps protect against liver tumors in mice
(12).
From our current study we concluded that, high sucrose induced obesity resulted in structural
and functional liver disturbance in adult rats, Green tea had a protective effect against these
dysfunction. In addition; green tea had a weight lowering and anti lipidemic effect and could
improve the fatty changes of the liver.
References
1-Choudhury J, Sanyal AJ(2004): Insulin resistance and the pathogenesis of nonalcoholic fatty
liver disease. Clin Liver Dis 8: 575–894.
2-Dobrian AD, Davies MJ, Prewitt RL, Lauterio TJ(2000):. Development of hypertension in a rat
model of diet-induced obesity. Hypertension.;35:1009–15.
3-Fried SK, Rao SP.( 2003): Sugar, hypertriglyceridemia, and cardiovascular disease. Am J Clin
Nutr.;78:873S–80.
11
4-Chen N, Bezzina R, Hinch E, Lewandowski PA, Cameron-Smith D, Mathai ML, Jois
M, Sinclair AJ, Begg DP, Wark JD, Weisinger HS, Weisinger RS.(2009): Green tea,
black tea, and epigallocatechin modify body composition, improve glucose tolerance, and
differentially alter metabolic gene expression in rats fed a high-fat diet; Nov;29(11):784-93.
doi: 10.1016/j.nutres.2009.10.003.
5-Westerterp-Plantenga MS. (2010): Green tea catechins, caffeine and body-weight regulation."
Physiol Behav. 26; 100(1):42-6.
6-Mitscher LA, Jung M, Shankel D, Dou JK, Steele L, Pillai SP. (1997):Chemoprevention: a review
of the potential therapeutic antioxidant properties of green tea, Med Res Rev; 17:327–65.
7-Yung-hsi Kao, Richard A Hiipakka, and Shutsung Liao;Modulation of obesity by a green tea
catechin, (2000) American Society for Clinical Nutrition; November 2000, vol. 72 no. 5 12321233.
8-Jae-Hyung Park and his colleagues (2013): from the Keimyung University School of Medicine in
the Republic of Korea conducted a study, now published in the Springer journal Naunyn-Apr. 29,
2013, Will Green Tea Help You Lose Weight?
9-Thomson Healthcare Inc. Green tea. (2007): In, PDR for Herbal Medicines. Compilation of short
monographs on herbal medications and dietary supplements 2007: pp. 414-22. 4th ed. Montvale,
New Jersey.
10-Kim et al.(2009): Ant fibrotic effects of green tea on in vitro and in vivo models of liver
fibrosis. World Journal of Gastroenterology,; 15 (41): 5200 DOI: 10.3748/wjg.15.5200
11-Skrzydlewska E, Ostrowska J, Farbiszewski R, Michalak K.,(2002):Protective effect of green
tea against lipid peroxidation in the rat liver, blood serum and the brain.;9(3):232-8.
12- Khan N, Adhami VM, Mukhtar H.(2009): Green tea polyphenols in chemoprevention of
prostate cancer: preclinical and clinical studies. ; 61(6):836-41. doi: 10.1080.
13-Roberts CK, Vaziri ND, Liang KH, Barnard RJ (2001): Reversibility of chronic experimental
syndrome X by diet modification. Hypertension, 37:1323-1328.
14-Zhi-Hong Yang*, Hiroko Miyahara, Jiro Takeo and Masashi Katayama (2012):Diet high in fat
and sucrose induces rapid onset of obesity-related metabolic syndrome partly through rapid
response of genes involved in lipogenesis, insulin signalling and inflammation in mice, 4:32.
15-Gisele A. Souza,1 Geovana X. Ebaid,2 Fábio R. F. Seiva,2 Katiucha H. R. Rocha,1 etal.(2011): NAcetylcysteine an Allium Plant Compound Improves High-Sucrose Diet-Induced Obesity and
Related Effects. Ecam/nen070. 10.1093-1100.
16-Yoshihisa Takahashi, Yurie Soejima, Toshio Fukusato(2012): Animal models of nonalcoholic
fatty liver disease/ nonalcoholic steatohepatitis .World J Gastroenterol 21; 18(19): 2300-2308.
17-Chan, P.C., Y. Ramot, D.E. Malarkey, P. Blackshear, G.E. Kissling, G. Travlos and A. Nyska,
(2010): Fourteen-week toxicity study of green tea extract in rats and mice. Toxicologic Pathology,
1070- :1084- (7) 38.
12
18-Stanhope KL, Schwarz JM, Keim NL, Griffen SC, Bremer AA, Graham JL, Hatcher B, Cox CL,
Dyachenko A, Zhang W, McGahan JP, Siebert A, Krauss RM et al. (2009): Consuming fructosesweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and
decreases insulin sensitivity in overweight/obese humans. J Clin Invest. Doi:10.1172/JCI37385.
19-Nagata R, Nishio Y, Sekine O, Nagai Y, Maeno Y, Ugi S, Maegawa H, Kashiwagi A(2004):
Single nucleotide polymorphism (-468 Gly to Ala) at the promoter region of sterol regulatory
element-binding protein-1c associates with genetic defect of fructose-induced hepatic
lipogenesis. J Biol Chem.; 279:29031–42.
02-Belza A, Toubro S, Astrup A.( 2007): The effect of caffeine, green tea and tyrosine on
thermogenesis and energy intake. Eur J Clin Nutr.; [Epub ahead of print].
21-Mead JR, Irvine SA, Ramji DP(2002): Lipoprotein lipase: structure, function, regulation, and
role in disease. J Mol Med, 80:753-769
20-Skrzydlewska E, Ostrowska J, Farbiszewski R, Michalak K (2002).;Protective effect of green
tea against lipid peroxidation in the rat liver, blood serum and the brain, 2002 Apr;9(3):232-8.
23-Yang M, Wang C, Chen H., (2001): Green, oolong and black tea extracts modulate lipid
metabolism in hyperlipidemia rats fed high-sucrose diet.;12(1):14-20.
24-N Nagaya, H Yamamoto, M Uematsu, T Itoh,K Nakagawa, T Miyazawa, K Kangawa, and K
Miyatake,(2004): Green tea reverses endothelial dysfunction in healthy smokers;; 90(12): 1485–
1486.
25-Jin X, Zheng RH, Li YM.; (2008): Green tea consumption and liver disease: a systematic
review, 2008 Aug;28(7):990-6. doi: 10.1111/j.1478-3231.2008.01776.x. Epub.
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