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White Tea extract induces lipolytic activity and inhibits adipogenesis in human subcutaneous (pre)-adipocytes

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The dramatic increase in obesity-related diseases emphasizes the need to elucidate the cellular and molecular mechanisms underlying fat metabolism. To investigate how natural substances influence lipolysis and adipogenesis, we determined the effects of White Tea extract on cultured human subcutaneous preadipocytes and adipocytes. For our in vitro studies we used a White Tea extract solution that contained polyphenols and methylxanthines. Utilizing cultured human preadipocytes we investigated White Tea extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. In vitro studies on human adipocytes were performed aiming to elucidate the efficacy of White Tea extract solution to stimulate lipolytic activity. To characterize White Tea extract solution-mediated effects on a molecular level, we analyzed gene expression of essential adipogenesis-related transcription factors by qRT-PCR and determined the expression of the transcription factor ADD1/SREBP-1c on the protein level utilizing immunofluorescence analysis. Our data show that incubation of preadipocytes with White Tea extract solution significantly decreased triglyceride incorporation during adipogenesis in a dose-dependent manner (n = 10) without affecting cell viability (n = 10). These effects were, at least in part, mediated by EGCG (n = 10, 50 μM). In addition, White Tea extract solution also stimulated lipolytic activity in adipocytes (n = 7). Differentiating preadipocytes cultivated in the presence of 0.5% White Tea extract solution showed a decrease in PPARγ, ADD1/SREBP-1c, C/EBPα and C/EBPδ mRNA levels. Moreover, the expression of the transcription factor ADD1/SREBP-1c was not only decreased on the mRNA but also on the protein level. White Tea extract is a natural source that effectively inhibits adipogenesis and stimulates lipolysis-activity. Therefore, it can be utilized to modulate different levels of the adipocyte life cycle.
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Nutrition & Metabolism
Open Access
Research
White Tea extract induces lipolytic activity and inhibits
adipogenesis in human subcutaneous (pre)-adipocytes
Jörn Söhle, Anja Knott, Ursula Holtzmann, Ralf Siegner, Elke Grönniger,
Andreas Schepky, Stefan Gallinat, Horst Wenck, Franz Stäb and
Marc Winnefeld*
Address: Research & Development, Research Special Skincare, Beiersdorf AG, Unnastrasse 48, 20245 Hamburg, Germany
Email: Jörn Söhle - Joern.Soehle@Beiersdorf.com; Anja Knott - Anja.Knott@Beiersdorf.com;
Ursula Holtzmann - Ursula.Holtzmann@Beiersdorf.com; Ralf Siegner - Ralf.Siegner@Beiersdorf.com;
Elke Grönniger - Elke.Groenniger@Beiersdorf.com; Andreas Schepky - Andreas.Schepky@Beiersdorf.com;
Stefan Gallinat - Stefan.Gallinat@Beiersdorf.com; Horst Wenck - Horst.Wenck@Beiersdorf.com; Franz Stäb - Franz.Staeb@Beiersdorf.com;
Marc Winnefeld* - Marc.Winnefeld@Beiersdorf.com
* Corresponding author
Abstract
Background: The dramatic increase in obesity-related diseases emphasizes the need to elucidate the
cellular and molecular mechanisms underlying fat metabolism. To investigate how natural substances
influence lipolysis and adipogenesis, we determined the effects of White Tea extract on cultured human
subcutaneous preadipocytes and adipocytes.
Methods: For our in vitro studies we used a White Tea extract solution that contained polyphenols and
methylxanthines. Utilizing cultured human preadipocytes we investigated White Tea extract solution-
induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. In
vitro studies on human adipocytes were performed aiming to elucidate the efficacy of White Tea extract
solution to stimulate lipolytic activity. To characterize White Tea extract solution-mediated effects on a
molecular level, we analyzed gene expression of essential adipogenesis-related transcription factors by
qRT-PCR and determined the expression of the transcription factor ADD1/SREBP-1c on the protein level
utilizing immunofluorescence analysis.
Results: Our data show that incubation of preadipocytes with White Tea extract solution significantly
decreased triglyceride incorporation during adipogenesis in a dose-dependent manner (n = 10) without
affecting cell viability (n = 10). These effects were, at least in part, mediated by EGCG (n = 10, 50 μM). In
addition, White Tea extract solution also stimulated lipolytic activity in adipocytes (n = 7). Differentiating
preadipocytes cultivated in the presence of 0.5% White Tea extract solution showed a decrease in PPARγ,
ADD1/SREBP-1c, C/EBPα and C/EBPδ mRNA levels. Moreover, the expression of the transcription factor
ADD1/SREBP-1c was not only decreased on the mRNA but also on the protein level.
Conclusion: White Tea extract is a natural source that effectively inhibits adipogenesis and stimulates
lipolysis-activity. Therefore, it can be utilized to modulate different levels of the adipocyte life cycle.
Published: 1 May 2009
Nutrition & Metabolism 2009, 6:20 doi:10.1186/1743-7075-6-20
Received: 3 November 2008
Accepted: 1 May 2009
This article is available from: http://www.nutritionandmetabolism.com/content/6/1/20
© 2009 Söhle et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Background
In the industrialized countries, the rising incidence of
obesity-associated disorders including cardiovascular dis-
eases and diabetes constitutes a growing problem. Due to
this increase in obesity-related diseases, cellular and
molecular processes underlying fat metabolism have been
studied extensively in recent years [1,2].
Adipose tissue represents a dynamic endocrine organ that
is present throughout the body forming different contigu-
ous or non-contiguous depots [1,3]. It serves as the body's
main energy reserve in periods of energy excess and ena-
bles fat mobilization during phases of food deprivation.
Apart from the regulation of the body's energy balance,
factors secreted from adipose tissue play key roles in the
modulation of metabolic processes, insulin sensitivity
and immunological responses [1].
An increase in adipose tissue mainly involves two proc-
esses: an increase in fat cell size (adipocyte hypertrophy)
as well as an increase in fat cell number (adipocyte hyper-
plasia). The formation of mature adipocytes from precur-
sor fat cells designated as preadipocytes is termed the
adipocyte life cycle [4-6]. It includes proliferation of
preadipocytes, fat cell differentiation (adipogenesis), lipo-
lytic-activity as well as apoptosis of preadipocytes or
mature adipocytes.
The complex sequence of preadipocyte differentiation is
initially triggered by transcription factor-activated signal-
ling pathways [7]. Three classes of transcription factors are
directly involved in adipogenesis: the peroxisome prolif-
erator-activated receptor γ (PPARγ), the CCAAT/enhancer
binding proteins (C/EBPα, C/EBPβ and C/EBPδ) and the
adipocyte determination and differentiation factor 1
(ADD1/SREBP-1c) [2]. PPARγ is a member of the PPAR
subfamily of nuclear hormone receptors. Like all mem-
bers of the PPAR family, PPARγ functions as an obligate
heterodimer with RXR. PPARγ is the most adipose specific
of the PPARs and its expression has been shown to be suf-
ficient to induce adipogenesis. In fact, PPARγ is the dom-
inant or 'master' regulator of adipogenesis [7,8]. The
second class of transcription factors critically involved in
adipocyte differentiation, the C/EBPs, are members of the
basic region leucine zipper transcription factor family.
Finally, ADD1/SREBP-1c is a member of the basic helix-
loop-helix family of transcription factors [9]. In addition
to its role in adipogenesis ADD1/SREBP-1c has been asso-
ciated with the regulation of genes linked to the choles-
terol metabolism. In this context, ADD1/SREBP-1c has
been termed sterol regulatory element binding protein 1c
(SREBP-1c) [10].
In the scientific literature, it is a subject of ongoing debate
whether polyphenols and/or xanthines can be utilized to
modulate different levels of the adipocyte life cycle [6]. A
combination of these different bioactive compounds is
naturally present in White Tea extract. In contrast to
Green- and Black Tea, White Tea is manufactured only
from the buds or first leaves of Camellia Sinensis that are
plucked and dried with minimal processing. Therefore,
the concentrations of epigallocatechin-3-gallate (EGCG)
and also methylxanthines (like caffeine) are enriched in
White Tea compared to Green- or Black Tea [11]. These
ingredients are known to exert biological effects on adi-
pocytes [12-19].
To investigate to what extent this natural plant extract
influences adipocyte hypertrophy and adipocyte differen-
tiation, we determined the effects of White Tea extract
solution on human preadipocytes and adipocytes. Our
data demonstrate the efficacy of this extract on different
levels of the cell metabolism that involve modulation of
adipogenesis-associated transcription factors.
Methods
White Tea extract solution
For our studies, a liquid leaf extract of Camellia Sinensis
(Actipone® White Tea GW; Lot 11; Symrise, Holzminden,
Germany) was used. This extract represents an aqueous
solution containing approximately 3% White Tea and
comprises high levels of EGCG (0.17%) and several other
polyphenols such as epigallocatechin and epicatechin as
well as the methylxanthines theobromine and caffeine.
For experiments, the extract was diluted in the respective
medium (see below) to a final concentration of 0.1%,
0.25%, 0.5%, 0.75% or 2% (v/v). To control for possible
glycerol effects, a respective glycerol solution in water was
used as control.
Differentiation of preadipocytes into adipocytes
Subcutaneous human preadipocytes isolated from but-
tocks, thighs or waists of different healthy subjects were
obtained from Cambrex (Verviers, Belgium) or Zenbio
Inc. (Research Triangle Park, NC). Cells were cultured
according to the manufacturer's instructions. Briefly, cells
were incubated in basal growth medium (Cambrex, Verv-
iers, Belgium) containing 10% fetal calf serum, 2 mM L-
glutamine, 100 U/ml penicillin and 100 μg/ml streptomy-
cin (Cambrex, Verviers, Belgium) for five (or seven) days
at 37°C and 5% (or 7.5%) CO2. Cells were seeded into
96-well plates (1 × 104 per well) or 6-well plates (3 × 105
per well) and after incubation overnight the differentia-
tion into adipocytes was initiated by addition of 10 μg/ml
insulin, 1 μM dexamethasone, 200 μM indomethacin and
500 μM isobutylmethylxanthine (Cambrex, Verviers, Bel-
gium) to the medium. Culture medium containing these
ingredients is designated as 'differentiation medium'.
Determination of cell viability
A viability assay determining the endogenous esterase
activity was used to evaluate possible cytotoxic effects of
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White Tea extract solution and EGCG. Briefly, preadi-
pocytes were cultured for seven days in the presence of
0.1%, 0.25%, 0.5% or 0.75% White Tea extract solution
or 50 μM EGCG dissolved in dimethylsulfoxide (DMSO),
respectively. Preadipocytes cultured in 'differentiation
medium' containing the respective control solution (glyc-
erol or DMSO) served as controls. Subsequently, cells
were washed with 1× Dulbecco's Phosphate Buffered
Saline (DPBS) (Cambrex, Verviers, Belgium) and incu-
bated for 20 min in 100 μl fluorescein diacetate (FDA)
(Sigma, Taufkirchen, Germany) solution (15 μg/ml FDA
in 1× DPBS). Fluorescence was then determined at 517
nm in the 96-well plate reader Safire 1 (Tecan, Crailsheim,
Germany).
Determination of triglyceride accumulation
For these experiments, cells were cultivated for seven days
in 'differentiation medium' supplemented with 0.1%,
0.25%, 0.5% or 0.75% White Tea extract solution, 50 μM
EGCG or the respective control solution.
The accumulation of triglycerides during differentiation
was determined on day seven by an AdipoRed Assay
(Cambrex, Verviers, Belgium) according to the manufac-
turer's instructions. Fluorescence was detected at 572 nm
and quantified in a 96-well plate reader Safire 1 (Tecan,
Crailsheim, Germany).
For additional microscopic analysis, cells were incubated
with AdipoRed reagent for 10 min at room temperature.
Samples were analyzed by fluorescence microscopy and
by phase contrast microscopy using an Olympus IX71
microscope (Hamburg, Germany).
Determination of glycerol release
Subcutaneous human preadipocytes were cultured
according to the manufacturer's instructions as described
above. Differentiation to adipocytes was achieved after
two weeks of culture in 'differentiation medium'. Prior to
incubation with test substances the differentiated cells (1
× 104 per 96-well) were cultured for one week in Dul-
becco's modified Eagle Medium low Glucose (Cambrex,
Verviers, Belgium) supplemented with 1% Bovine Albu-
min Fraction V, 100 U/ml penicillin, 100 μg/ml strepto-
mycin and 1× Glutamax (all obtained from Gibco/BRL,
Eggenstein, Germany). Culture medium containing these
ingredients is designated as 'maintenance medium'.
For experiments, cells were incubated in 150 μl 'mainte-
nance medium' containing either 2% White Tea extract
solution or control solution for 24 hrs at 37°C and 7.5%
CO2. The medium was removed and cells were washed
twice with phosphate buffered saline (PBS). Cells were
incubated for another five days in 'maintenance medium'
prior to quantification of glycerol release. For every donor,
seven samples were prepared both for control and White
Tea incubation.
Free glycerol reagent and standard solution (Sigma,
Taufkirchen, Germany, standard dilution: 125 to 1.95 μg/
ml (1:1 steps)) were used according to the manufacturer's
instructions. For measurement either 120 μl supernatant
or standard solution were used for each sample and mixed
with 100 μl of free glycerol reagent in a 96-well. After 15
min incubation at room temperature in the dark, absorp-
tion was measured in a 96-well plate reader Spectra MAX
Plus (Molecular Devices, Union City, California, USA) at
540 nm.
Gene expression of adipogenesis-associated transcription
factors
Subcutaneous human preadipocytes were cultured as
described above. For experiments, cells were cultivated for
five days in 'differentiation medium' with or without
0.5% White Tea extract solution. Cells were harvested on
day five after induction of differentiation and homoge-
nized in TRIzol® (Invitrogen, Karlsruhe, Germany) follow-
ing the manufacturer's protocol. After reverse
transcription, samples were analyzed for the following
transcription factors PPARγ, ADD1/SREBP-1c, C/EBPα, C/
EBPβ and C/EBPδ by Real-Time TaqMan®-PCR using the
7900 HT Fast-Real-Time PCR System (Applied Biosys-
tems, Darmstadt, Germany).
FAM labelled primers for the qRT-PCR (Applied Biosys-
tems, Forster City, California, USA) were as follows:
Inventoried TaqMan Assays for the internal control glycer-
aldehyde-3-phosphate dehydrogenase (GAPDH; Hs99
999905_m1), for the target RNA PPARγ (Hs00 234592
_m1), ADD1/SREBP-1c (Hs01088691_m1), C/EBPα
(Hs00269972_s1), C/EBPβ (Hs00270923_s1) and C/
EBPδ (Hs00270931_s1). PCR conditions were as follows:
50°C for 2 min, 94.5°C for 10 min followed by 40 cycles
at 97°C for 30 sec and 59.7°C for 1 min. Real-time PCR
data were analyzed using the Sequence detector version
2.3 software supplied with the 7900 HT Fast-Real-Time
PCR System (Applied Biosystems, Darmstadt, Germany).
Quantification was achieved using the 2-ΔΔCt method
which calculates the relative changes in gene expression of
the target normalized to an endogenous reference
(GAPDH) and relative to a calibrator that serves as the
control group.
Immunofluorescence microscopic analysis
For immunofluorescence analysis, preadipocyte popula-
tions were incubated in 'differentiation medium' with or
without 0.5% White Tea extract solution for 10 days as
described above. Cells were grown on coverslips and for
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Incell-Western analysis in 96-well plates. In the following,
cells were fixed with 4% formaldehyde solution for 30
min at room temperature, washed with PBS and permea-
bilized with 0.2% Triton X-100. After successive washing
with PBS, fixed cells were pre-treated with PBS containing
10% donkey-serum for 30 min. Cells were then incubated
for 1 h with primary antibodies directed against ADD1/
SREBP-1c (sc 8984; Santa Cruz, Heidelberg, Germany)
and GAPDH (sc-47724; Santa Cruz, Heidelberg, Ger-
many). Coverslips and 96-well plates were successively
rinsed three times with PBS, and then incubated for 1 h
with secondary antibodies labelled with Cy3 (microscopic
analysis), IRDye680 or IRDye-800 (Incell-Western analy-
sis). Results were determined using the Fluorescence
microscope IX71 in combination with the software cell^F
v. 2.4 (Olympus, Hamburg, Germany). Incell-Western
analyses were carried out using the Odyssey Infrared
Imager (Li-Cor Biosciences, Bad Homburg, Germany).
Determination of Sirt1 gene expression
Human preadipocytes were cultured in 'differentiation
medium' in the absence or presence of 0.5% White Tea
extract solution as described above. Cells were harvested
on day five after induction of differentiation and homog-
enized in TRIzol® (Invitrogen, Karlsruhe, Germany) fol-
lowing the manufacturer's protocol. After reverse
transcription, samples were analyzed for Sirt1 by Real-
Time TaqMan®-PCR using the 7900 HT Fast-Real-Time
PCR System (Applied Biosystems, Darmstadt, Germany).
FAM labelled primers for the qRT-PCR (Applied Biosys-
tems, Forster City, CA) were as follows: Inventoried Taq-
Man Assays for the internal control GAPDH
(Hs99999905_m1) and for the target RNA Sirt1
(Hs01009006_m1). PCR conditions were as follows:
50°C for 2 min, 94.5°C for 10 min followed by 40 cycles
at 97°C for 30 sec and 59.7°C for 1 min. Real-time PCR
data were analyzed using the Sequence detector version
2.3 software supplied with the 7900 HT Fast-Real-Time
PCR System (Applied Biosystems, Darmstadt, Germany).
Quantification was achieved using the 2-ΔΔCt method
which calculates the relative changes in gene expression of
the target normalized to an endogenous reference
(GAPDH) and relative to a calibrator that serves as the
control group.
Statistical analysis
A significance level of 0.05 (alpha) was chosen for statis-
tical analysis, based on two-sided hypothesis testing. For
the analysis SAS software package for Windows V9.1.3
was used.
Depending on the parameter investigated the following
analyses were conducted:
Determination of triglyceride accumulation, ADD1/SREBP-1c protein
expression and cell viability
• Test of normality using Shapiro-Wilk's test
• If rejection of the normality hypothesis: analysis of the
Blom-transformed ranks of the original data, otherwise
analysis of original data
• Comparison versus control via repeated measures anal-
ysis of variance with qualitative factor treatment
Determination of glycerol release
• Comparison versus control by means of Wilcoxon
signed rank test
Results
White Tea extract solution decreases triglyceride
accumulation without affecting cell viability
To investigate effects of White Tea extract on triglyceride
accumulation during human preadipocyte/adipocyte dif-
ferentiation in vitro, cells were cultured in 'differentiation
medium' for seven days (n = 10) in the absence or pres-
ence of 0.1%, 0.25%, 0.5% or 0.75% White Tea extract
solution. The total amount of lipid accumulation was
determined (Figure 1A). Cells treated with White Tea
extract solution dose-dependently exhibited significantly
decreased triglyceride levels (p < 0.0001). Compared to
control cells (set as 100%), White Tea extract solution
reduced triglyceride accumulation up to 70%.
As illustrated in Figure 1B, the majority of control cells
accumulated triglycerides (yellow staining) in the lipid
droplets. These cells are characterized by lipid droplets
filling almost the entire cell while the cytoplasm is being
shifted to the periphery. In contrast, cells incubated with
0.5% White Tea extract solution did not accumulate lipid
droplets as indicated by the absence of yellow staining.
The few vesicles that could be detected were smaller in size
compared to the respective control.
In addition, a viability assay was used to determine any
possible adverse effects of White Tea extract solution (n =
10). Control cells (set as 100%) and preadipocytes culti-
vated in 'differentiation medium' with 0.1%, 0.25%, 0.5%
or 0.75% White Tea extract solution displayed a compara-
ble esterase activity indicating that the viability of cultured
cells was not affected by incubation with White Tea extract
solution (Figure 1C). These results are in good agreement
with observations from phase contrast microscopy shown
in Figure 1D. Cell populations cultivated in 'differentia-
tion medium' in the presence (0.5%) or absence of White
Tea extract solution grew to comparable cell densities.
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White Tea extract solution increases glycerol release
To address the question whether White Tea extract solu-
tion also stimulates lipolysis-activity in differentiated adi-
pocytes, we determined if incubation of these cells (n = 7)
with White Tea extract solution influences the degrada-
tion of triglycerides. As our studies show, treatment of adi-
pocytes with 2% White Tea extract solution significantly
(p = 0.016) increased the content of free glycerol to 32 (±
18) μg/ml as compared to control cells at 20 (± 18) μg/ml
(Figure 2).
Effect of White Tea extract solution on ADD1/SREBP-1c
protein expression
Since our results (Figure 1A–D) indicated a White Tea-
mediated reduction of triglyceride accumulation during
adipogenesis we investigated the underlying mechanism
of action in more detail. Therefore, we determined the
protein level of an essential adipogenic transcription fac-
tor – ADD1/SREBP-1c – by immunofluorescence analysis.
Interestingly, stimulation with White Tea extract solution
substantially down-regulated ADD1/SREBP-1c protein
expression during adipogenesis compared to control cells
(Figure 3A and 3B). Moreover, Incell-Western analyses
were performed to quantify ADD1/SREBP-1c expression.
Effects of White Tea extract solution on triglyceride accumu-lation during preadipocyte/adipocyte differentiationFigure 1
Effects of White Tea extract solution on triglyceride
accumulation during preadipocyte/adipocyte differ-
entiation. (A) Triglyceride accumulation and (C) cell viabil-
ity of maturing preadipocytes incubated with different
amounts of White Tea extract solutions (0.1%, 0.25%, 0.5%
and 0.75%) is shown relative to untreated control cells set as
100%. For experiments, ten independent cell cultures were
prepared both for control and White Tea extract solution
incubation (n = 10). Results are depicted as mean ± SD. Sig-
nificant differences are marked with an asterisk (* for p <
0.0001). (B) Images after triglyceride staining (yellow) from
cell populations incubated with and without 0.5% White Tea
extract solution. Scale bar: 200 μm. (D) Displayed are phase
contrast images from cell populations cultivated in the
absence or presence of 0.5% White Tea extract solution.
Scale bar: 50 μm. For our studies we used cells up to the
third passage.
control
control 0.5% White Tea extract
solution
D
B
A
C
0
20
40
60
80
100
120
relative change in tri-
glyceride accumulation [%]
White Tea extract solution
control 0.1% 0.25% 0.5% 0.75%
****
0.5% White Tea extract
solution
0
20
40
60
80
100
120
control 0.1% 0.25% 0.5% 0.75%
cell viability [%]
White Tea extract solution
Determination of glycerol release in differentiated adipocytes after incubation with White Tea extract solutionFigure 2
Determination of glycerol release in differentiated
adipocytes after incubation with White Tea extract
solution. Glycerol content is given in μg/ml. For experi-
ments, seven independent cell cultures were prepared both
for control and White Tea extract solution incubation (n =
7). Results are depicted as mean ± SD. Significant differences
are marked with an asterisk (* for p 0.05). For our studies
we used cells up to the third passage.
ȝ
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Compared to controls (set as 100%), cells incubated in
the presence of 0.5% White Tea extract solution showed a
significantly (p < 0.0001) decreased ADD1/SREBP-1c
expression to 44 (± 6)% (Figure 3C, E) whereas GAPDH
expression was not affected (Figure 3D).
Effects of White Tea extract solution on the gene
expression of adipogenesis-associated transcription
factors
To gain insight into the molecular events associated with
the above described inhibition of adipocyte differentia-
tion, cells were cultivated in the presence or absence of
0.5% White Tea extract solution for five days after initia-
tion of differentiation and gene expression of the tran-
scription factors PPARγ, ADD1/SREBP-1c, C/EBPα, C/
EBPβ and C/EBPδ was determined relative to control cells
by quantitative RT-PCR (Figure 4; n = 3). Compared to
control cells (set as 100%), cells incubated with White Tea
extract solution display a decrease in mRNA levels of
PPARγ (19% ± 6%), ADD1/SREBP-1c (64% ± 5%), C/
EBPα (5% ± 2%) and C/EBPδ (58% ± 25%). The expres-
sion of C/EBPβ mRNA, however, was not affected (95% ±
26%).
White Tea extract solution decreases Sirt1 gene expression
The enzyme Sirt1 has been implicated in the process of
adipogenesis [20]. Accordingly, we investigated whether
the effects of White Tea extract solution on adipogenesis
are paralleled by an altered Sirt1 gene expression. Com-
pared to the untreated controls (set as 100%), cells incu-
bated with 0.5% White Tea extract solution (n = 3)
displayed a decrease in Sirt1 mRNA levels to 64 (± 28)%
(Figure 5).
Effects of EGCG on triglyceride accumulation and cell
viability
The White Tea extract solution used in our studies con-
tained as a main component EGCG. In order to investi-
gate the possibility that EGCG is responsible for the
reduced adipocyte differentiation observed in cell popula-
tions cultivated in the presence of White Tea extract solu-
tion, we analyzed EGCG effects. As shown in Figure 6A,
cells cultured for seven days (n = 10) in 'differentiation
medium' containing 50 μM EGCG displayed reduced trig-
lyceride levels (p < 0.0001) of 33 (± 10)% compared to
control cells (set as 100%).
Effect of White Tea extract solution on ADD1/SREBP-1c expression during adipogenesisFigure 3
Effect of White Tea extract solution on ADD1/
SREBP-1c expression during adipogenesis. Preadi-
pocyte populations (0 d) were incubated with differentiation
medium without (A) and with (B) 0.5% White Tea extract
solution for 10 days. A and B: ADD1/SREBP-1c was detected
by immunofluorescence microscopic analysis. Scale bar: 200
μm. C-E: Quantitative analyses were performed using the
Odyssey Infrared Imager. 1 and 3: Cells incubated in control
solution. 2 and 4: Cells incubated in the presence of White
Tea extract solution. For experiments, 17 independent cell
cultures were prepared both for control and White Tea
extract solution incubation (n = 17). Results are depicted as
mean ± SD. Significant differences are marked with an aster-
isk (* for p < 0.0001).
ADD1/SREBP-1c expression
GAPDH exp ression
D
CE
B
A
control 0.5% Whit e Tea extract solut ion
0
20
40
60
80
100
120
control 0.5% Whit e Tea
extract solution
ADD1/SREBP-1c protei n expression [%]
*
B
A
1
2
3
4
1
2
3
4
Effects of White Tea extract solution on gene expression of adipogenesis-associated transcription factorsFigure 4
Effects of White Tea extract solution on gene
expression of adipogenesis-associated transcription
factors. Gene expression of PPARγ, ADD1/SREBP-1c, C/
EBPα, C/EBPβ and C/EBPδ in differentiating preadipocytes
after incubation with White Tea extract solution compared
to control cells set as 100%. Expression of each gene is nor-
malized to GAPDH. Three independent experiments were
prepared both for control and White Tea extract solution
incubation (n = 3). Results are depicted as mean ± SD. For
our studies we used cells up to the third passage.
0
20
40
60
80
100
120
mRNA expression [%]
ADD1/
SREBP-1c
control PPARȖC/EBPĮC/EBPß C/EBPį
0.5% White Tea extract
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In contrast to cell populations incubated with White Tea
extract solution, maturing preadipocytes (n = 10) cultured
in the presence of 50 μM EGCG showed an esterase activ-
ity of 78 (± 6)% compared to control cells (set as 100%)
indicating that EGCG slightly impairs cell viability during
adipogenesis (Figure 6B)(p < 0.0001).
Discussion
In the human body, adipose tissue is present as both vis-
ceral and subcutaneous fat. Apart from other functions, its
main role is associated with the storage of energy. In peri-
ods of food overabundance, human adult adipose tissue
maintains its ability to increase the number of adipocytes
suggesting that differentiation of preadipocytes can occur
at any time in response to nutritional or hormonal stimu-
lants [3].
A large body of evidence indicates that certain plant
extracts and their respective bioactive components might
have direct effects on adipose tissue [6]. Based on these
data, the overall objective of our studies was to investigate
the effects of a particular White Tea extract solution on fat
accumulation and the expression of adipocyte-specific
genes in primary human preadipocyte and adipocyte cul-
ture.
In previous studies polyphenols as well as various natural
extracts were shown to induce apoptosis, decrease lipid
accumulation and stimulate lipolysis in preadipocytes
and adipocytes [6,13,17]. These results, however, were
mainly obtained studying 3T3-L1 cells. Although this
mouse cell line represents a well-established model sys-
White Tea extract solution decreases Sirt1 gene expressionFigure 5
White Tea extract solution decreases Sirt1 gene
expression. Sirt1 gene expression in differentiating preadi-
pocytes after incubation with 0.5% White Tea extract solu-
tion is shown relative to untreated control cells set as 100%.
Gene expression is normalized to GAPDH. Three independ-
ent experiments were prepared both for control and White
Tea extract solution incubation (n = 3). Results are depicted
as mean ± SD. For our studies we used cells up to the third
passage.
0
20
40
60
80
100
120
Sirt1 mRNA expression [%]
control 0.5% White Tea
extract solution
Decrease in triglyceride concentration and cell viability in dif-ferentiating preadipocytes after stimulation with EGCGFigure 6
Decrease in triglyceride concentration and cell viabil-
ity in differentiating preadipocytes after stimulation
with EGCG. (A) Triglyceride content in differentiating
preadipocytes after stimulation with 50 μM EGCG is shown
relative to untreated control cells set as 100%. For experi-
ments, ten independent cell cultures were prepared both for
control and EGCG incubation (n = 10). Results are depicted
as mean ± SD. Significant differences are marked with an
asterisk (* for p < 0.0001). (B) Decreased viability in differen-
tiating preadipocytes after stimulation with 50 μM EGCG
compared to control cells. Cell viability is shown relative to
untreated control cells set as 100%. For experiments, ten
independent cell cultures were prepared both for control
and EGCG incubation (n = 10). Results are depicted as mean
± SD. Significant differences are marked with an asterisk (*
for p < 0.0001). For our studies we used cells up to the third
passage.
ȝ
ȝ
Nutrition & Metabolism 2009, 6:20 http://www.nutritionandmetabolism.com/content/6/1/20
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tem to study fat metabolism [21], 3T3-L1 cells differ in
various aspects from primary cells isolated from fat tissue.
Furthermore, it has been widely accepted that significant
differences in adipose tissue biology exist between species.
To account for these known differences, we exclusively
utilized primary cultured human cells for our experi-
ments. Compared to murine 3T3-L1 cells, human preadi-
pocytes and adipocytes should better reflect the human
lipid metabolism and, hence, the human in vivo situa-
tion.
Natural White Tea represents the least processed form of
tea and comprises high levels of EGCG and several other
polyphenols such as epigallocatechin and epicatechin as
well as the methylxanthines theobromine and caffeine.
As our data show, incubation with White Tea extract solu-
tion decreases triglyceride incorporation in human pread-
ipocytes during adipogenesis (Figure 1A, B). Importantly,
this significant reduction in triglyceride accumulation is
not due to toxic side effects (Figure 1C, D).
One possible explanation for the observed attenuation in
triglyceride incorporation during adipogenesis could be
the ability of White Tea extract solution to stimulate lipo-
lytic activity as evidenced by an increased conversion of
triglyceride to fatty acids and glycerol. Interestingly
indeed, by measuring glycerol release we were able to
demonstrate that White Tea extract solution augments
lipolysis-activity in differentiated adipocytes (Figure 2).
However, the degree of lipolysis-activity induced by White
Tea extract solution is not sufficient enough to fully
explain the observed reduction in triglyceride incorpora-
tion. In addition to this effect one could hypothesize that
White Tea extract solution also inhibits adipogenesis on a
molecular level. Accordingly, we investigated the effects of
White Tea extract solution on the expression pattern of
ADD1/SREBP-1c an essential adipogenesis-related tran-
scription factor. ADD1/SREBP-1c is highly expressed in
the liver and in adipose tissue and plays an important role
in adipocyte differentiation [9]. ADD1/SREBP-1c mRNA
levels are increased in determined preadipocytes and to a
greater extend augmented during the differentiation proc-
ess [22]. Interestingly, ADD1/SREBP-1c has been shown
to promote PPARγ expression [1,2] further stressing its
physiological relevance.
To study ADD1/SREBP-1c regulation in more detail, we
investigated its protein expression following treatment
with White Tea extract solution. Compared to differenti-
ated adipocytes, that display an augmented ADD1/
SREBP-1c expression (control, Figure 3A), cells incubated
in the presence of White Tea extract solution show only a
weak ADD1/SREBP-1c signal (Figure 3B). This observa-
tion together with quantitative analysis (Figure 3C–E)
clearly shows that White Tea extract solution influences
adipocyte differentiation.
Beside ADD1/SREBP-1c, several transcription factors are
involved in orchestrating adipocyte differentiation [2,3].
Briefly, adipogenesis is initiated by the transient expres-
sion of C/EBPβ and C/EBPδ. In response to adipogenic
signals, these transcription factors lead to the activation of
PPARγ which in turn stimulates the expression of C/EBPα.
C/EBPα again exerts positive feedback on PPARγ to main-
tain the differentiation process [8].
To gain more mechanistic insights into the signalling cas-
cade that is stimulated by White Tea extract solution, we
investigated the expression of the essential transcription
factors PPARγ, ADD1/SREBP-1c, C/EBPα, C/EBPβ and C/
EBPδ. Interestingly, our results illustrate that cells incu-
bated with White Tea extract solution display a decrease in
PPARγ, ADD1/SREBP-1c, C/EBPα and C/EBPδ mRNA lev-
els during adipogenesis while the expression of C/EBPβ
mRNA was not affected (Figure 4). Overall, the observed
reduction of adipogenesis-related transcription factors
supports the notion that White Tea extract solution acts
on two different levels, by increasing lipolysis and by
inhibiting adipogenesis.
However, it should be noted that the results presented
here were achieved using subcutaneous human (pre)-adi-
pocytes. When using visceral human (pre)-adipocytes,
neither White Tea extract solution nor EGCG significantly
reduced triglyceride accumulation (data not shown). One
explanation for this phenomenon could be that PPARγ
activity is considerably lower in primary human visceral
adipocytes [23] compared to subcutaneous adipocytes.
Since our results show that White Tea extract solution acts
by decreasing PPARγ mRNA expression in subcutaneous
(pre)-adipocytes these data might explain the different
actions observed in subcutaneous and visceral cells.
Another interesting facet that is a matter of intense
research is the role of sirtuins in fat metabolism. Sirtuins
belong to a family of enzymes implicated in apoptosis
and fatty acid metabolism, to name two physiological
functions. Mammalian sirtuins comprises of the seven
members, Sirt1 – Sirt7 [24]. Sirt1 regulates adipogenesis
by inhibiting the expression of genes that control adi-
pocyte differentiation and also triglyceride accumulation
in 3T3-L1 cells. Sirt1 over-expression results in a reduction
of PPARγ, C/EBPα and C/EBPδ but not C/EBPβ mRNA
indicating that Sirt1 functions as a repressor of genes that
control adipocyte differentiation [20].
Along these lines it is interesting to note that the estab-
lished Sirt1 activator resveratrol, a polyphenol, inhibits
adipogenesis in maturing 3T3-L1 preadipocytes [25].
Nutrition & Metabolism 2009, 6:20 http://www.nutritionandmetabolism.com/content/6/1/20
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Accordingly, it appears plausible that polyphenols present
in White Tea extract solution could reduce adipogenesis
by means of an increased Sirt1 enzyme expression.
To tackle this question we determined Sirt1 mRNA expres-
sion after stimulation with White Tea extract solution.
Interestingly, our data showed a slight reduction in Sirt1
gene expression suggesting that the polyphenols present
in White Tea extract solution do not reduce adipogenesis
via modulation of Sirt1 levels (Figure 5). The observed
decrease in Sirt1 mRNA levels could be explained by the
fact that Sirt1 expression is per se increased during fat cell
differentiation [20]. Therefore, a decrease in adipogenesis
induced by White Tea extract solution could indirectly
affect Sirt1 mRNA expression.
Moreover, no increase in Sirt1-activity was detected in the
presence of 0.5% White Tea extract solution using a cell
free Sirt1 activity assay (unpublished data). However, fur-
ther studies need to be conducted in the future to eluci-
date the exact mechanism in more detail and to
corroborate this finding.
Our results discussed above show that treatment of pri-
mary human (pre)-adipocytes with White Tea extract
solution modulates both adipogenesis and lipolysis.
These White Tea extract solution-induced effects are asso-
ciated with a decrease in the expression of adipogenesis-
associated transcription factors as well as a diminished
gene expression of Sirt1. One possible explanation to
account for these rather complex effects could be the fact
that White Tea extract solution is composed of several
active ingredients, among them polyphenols and methyl-
xanthines.
To elucidate the possible effects of polyphenols in more
detail, we investigated the influence of EGCG on triglycer-
ide accumulation during differentiation in human pre-
adipoyctes. EGCG represents the most abundant catechin
present in White Tea extract solution. In that context it is
important to remark that conflicting data have been pub-
lished with respect to the effects of EGCG on (pre-)adi-
pocytes. While EGCG inhibits adipogenesis in 3T3-L1
cells [15] it did not affect the conversion of preadipocytes
to adipocytes in human AML-1 cells [16]. Our results
using human primary preadipocytes show that EGCG
reduces triglyceride incorporation during adipogenesis
(Figure 6). Considering our hypothesis the EGCG-medi-
ated decrease in triglyceride accumulation might be due to
an EGCG-induced inhibition of adipogenesis.
Previous studies also showed that EGCG did not promote
lipolysis in both 3T3-L1 [13] and C3H10T1/2 cells [14].
These observations indicate that the stimulated lipolytic
activity induced by White Tea extract solution might not
be mediated by EGCG.
On the other hand, methylxanthines have been reported
to stimulate triglyceride conversion by inhibiting phos-
phodiesterase 3B activity and subsequently increasing
cAMP levels [18,19]. Unpublished data from our lab show
that caffeine (5 mM) increases lipolysis-activity in human
adipocytes. Therefore, the observed White Tea-mediated
increase in lipolysis-activity might, at least in part, be
caused by methylxanthines.
Adding more to the complexity, EGCG not only influ-
ences triglyceride accumulation during adipogenesis but
also the process of apoptosis. In both 3T3-L1 and AML-1
cells stimulation with EGCG induced apoptotic cell death
[15,16]. Our observation that the viability of primary
human preadipocytes is reduced in the presence of EGCG
appears to be in line with these studies. However, treat-
ment with White Tea extract solution did not impair cell
viability. Although we did not specifically study apopto-
sis, it can be speculated that other natural substances
present in White Tea extract solution might counteract the
EGCG-mediated reduction of cell viability.
Conclusion
The increase of obesity-related diseases highlights the
need to further investigate the cellular and molecular
mechanisms underlying fat metabolism. In this context,
we determined the effects of a particular White Tea extract
solution on fat accumulation and the expression of adi-
pocyte-specific genes in primary human preadipocyte and
adipocyte cultures.
Overall, our data demonstrate that White Tea extract solu-
tion effectively inhibits adipogenesis and stimulates lipol-
ysis-activity. This plant extract is, therefore, an ideal
natural source to modulate the adipocyte life cycle at dif-
ferent stages and to induce anti-obesity effects.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
JS performed the experiments concerning adipogenic
transcription factors. Moreover, he assisted with interpre-
tation of the results and helped draft the manuscript. AK
analyzed the lipolytic activity of differentiated adipocytes.
RS and UH analyzed the triglyceride accumulation during
adipocyte differentiation. EG performed (in cooperation
with JS) LDA-analysis (adipogenic transcription factors).
AS, SG, HW, FS assisted with interpretation of the results.
MW supervised the analyses and helped to draft the man-
uscript. All authors read and approved the final manu-
script.
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Nutrition & Metabolism 2009, 6:20 http://www.nutritionandmetabolism.com/content/6/1/20
Page 10 of 10
(page number not for citation purposes)
Acknowledgements
We kindly thank Mrs. Leneveu-Duchemin (Biometrics, Beiersdorf AG) for
conducting expert statistical analysis.
References
1. Gregoire FM: Adipocyte differentiation: From fibroblast to
endocrine cell. Exp Biol Med (Maywood). 2001, 226(11):997-1002.
2. Rosen ED, Walkey CJ, Puigserver P, Spiegelman BM: Transcrip-
tional regulation of adipogenesis. Genes De 2000,
14(11):1293-1307.
3. Avram MM, Sharpe Avram A, James WJ: Subcutaneous fat in nor-
mal and diseased states 3. Adipogenesis: From stem cell to
fat cell. J Am Acad Dermatol 2007, 56(3):472-492.
4. Hirsch J, Batchelor B: Adipose tissue cellularity in human obes-
ity. Clin Endocrinol Metab 1976, 5(2):299-311.
5. Rodeheffer MS, Birsoy K, Friedman JM: Identification of white adi-
pocyte progenitor cells in vivo. Cell 2008, 135(2):240-249.
6. Rayalam S, Della-Fera MA, Baile CA: Phytochemicals and regula-
tion of the adipocyte life cycle. J Nutr Biochem 2008,
19(11):717-726.
7. Gregoire FM, Smas CM, Sul HS: Understanding adipocyte differ-
entiation. Physiol Rev 1998, 78(3):783-809.
8. Tontonoz P, Spiegelman BM: Fat and beyond: the diverse biology
of PPARgamma. Annu Rev Biochem 2008, 77:289-312.
9. Kim JB, Spiegelman BM: ADD1/SREBP1 promotes adipocyte dif-
ferentiation and gene expression linked to fatty acid metab-
olism. Genes Dev 1996, 10:1096-1107.
10. Yokoyama C, Wang X, Briggs MR, Admon A, Wu J, Hua X, Goldstein
JL, Brown MS: SREBP-1, a basic-helixloop-helix-leucine zipper
protein that controls transcription of the low density lipo-
protein receptor gene. Cell 1993, 75:187-197.
11. Hilal Y, Engelhardt U: Characterisation of white tea – Compar-
ison to green and black tea. J Verbr Lebensm 2007, 2:414-421.
12. Moon H-S, Lee H-G, Choi Y-J, Kim T-G, Cho C-S: Proposed mech-
anism of (-)-epigallocatechin-3-gallate for anti-obesity. Chem
Biol Interact 2007, 167:85-98.
13. Moon H-S, Chung C-S, Lee H-G, Kim T-G, Choi Y-J, Cho C-S: Inhib-
itory effect of (-)-epigallocatechin-3-gallate on lipid accumu-
lation of 3T3-L1 cells. Obesity (Silver Spring) 2007,
15(11):2571-2582.
14. Wolfram S, Wang Y, Thielecke F: Anti-obesity effects of green
tea: from bedside to bench. Mol Nutr Food Res 2006,
50(2):176-187.
15. Lin J, Della-Fera MA, Baile CA: Green tea polyphenol epigallo-
catechin gallate inhibits adipogenesis and induces apoptosis
in 3T3-L1 adipocytes. Obes Res 2005, 13(6):982-990.
16. Morikawa K, Ikeda C, Nonaka M, Pei S, Mochizuki M, Mori A, Yamada
S: Epigallocatechin gallate-induced apoptosis does not affect
adipocyte conversion of preadipocytes. Cell Biol Int 2007,
31(11):1379-1387.
17. Furuyashiki T, Nagayasu H, Aoki Y, Bessho H, Hashimoto T,
Kanazawa K, Ashida H: Tea catechin suppresses adipocyte dif-
ferentiation accompanied by down-regulation of PPARγ2
and C/EBPα in 3T3-L1 cells. Biosci Biotechnol Biochem 2004,
68(11):2353-2359.
18. Peers DG, Davies JI: Significance of the caffeine-like effect of
various purines, pyrimidines and derivatives on adipose-tis-
sue phosphodiesterase. Biochem J 1971, 124(2):8P-9P.
19. Duncan RE, Ahmadian M, Jaworski K, Sarkadi-Nagy E, Sul HS: Regu-
lation of lipolysis in adipocytes. Annu Rev Nutr 2007, 27:79-101.
20. Picard F, Kurtev M, Chung N, Topark-Ngarm A, Senawong T, Mach-
ado de Oliveira R, Leid M, McBurney MW, Guarente L: Sirt1 pro-
motes fat mobilization in white adipocytes by repressing
PPAR-γ. Nature 2004, 429:771-776.
21. Green H, Kehinde O: Sublines of mouse 3T3 cells that accumu-
late lipid. Cell 1974, 1:113-116.
22. Tontonoz P, Kim JB, Graves RA, Spiegelman BM: ADD1: A novel
helix-loop-helix transcription factor associated with adi-
pocyte determination and differentiation. Mol Cell Biol 1993,
13:4753-4759.
23. Sauma L, Franck N, Paulsson JF, Westermark GT, Kjølhede P, Strål-
fors P, Söderström M, Nystrom FH: Peroxisome proliferator
activated receptor gamma activity is low in mature primary
human visceral adipocytes. Diabetologia 2007, 50(1):195-201.
24. Michan S, Sinclair D: Sirtuins in mammals: insights into their
biological function. Biochem J 2007, 404(1):1-13.
25. Rayalam S, Yang JY, Ambati S, Della-Fera MA, Baile CA: Resveratrol
induces apoptosis and inhibits adipogenesis in 3T3-L1 adi-
pocytes. Phytother Res 2008, 22(10):1367-1371.
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Ethnopharmacological relevance Diabetic kidney damage (DKD) is one of the most common complications of diabetes, which is known as a chronic inflammatory kidney disease caused by persistent hyperglycemia. White tea was originally used as a folk medicine to treat measles in ancient China. What arouses our interest is that there is a traditional method to treat diabetes with white tea taken from over 30-year-old tree of Camellia sinensis L. However, there are few reports on the renal protection of white tea. Aim of the study: This present study was designed to study the potential protective effects of white tea (WT) and old tree white tea (OTWT) on high-fat-diet (HFD) combined with streptozotocin (STZ)-induced type 2 diabetic mice to explore the possible mechanism of WT/OTWT against DKD. Materials and methods C57BL/6 mice were randomly divided into four groups: NC, T2D, WT (400 mg/kg·b.w, p.o.), OTWT (400 mg/kg·b.w, p.o.). Diabetes was established in all groups except NC group, by six weeks of HFD feeding combined with STZ (50 mg/kg, i.p.) for 3 times, treatments were administered for six weeks and then all the animals were decapitated; kidney tissues and blood samples were collected for the further analysis, including: levels of insulin, lipid metabolism (TG, TC, HDL, LDL, FFA), antioxidative enzymes (catalase (CAT), super oxide dismutase (SOD), glutathione peroxidase (GPx)), blood urea nitrogen (BUN) and creatine, inflammatory cytokines (TNF-α, IL-1β, COX-2, iNOS, MCP-1), advanced glycation end products (AGE), receptor of AGE (RAGE), Nrf2, AMPK, SIRT1, and PGC-1α. H&E, PAS and Masson staining were performed to examine the histopathological alterations of the kidneys. Results Our data showed that WT and OTWT reversed the abnormal serum lipids (TG, TC, HDL, LDL, FFA) in T2D mice, upregulated antioxidative enzymes levels (CAT, SOD, GPx) and inhibit the excessive production of proinflammatory mediators (including MCP-1, TNF-α, IL1β, COX-2 and iNOS) by varying degrees, and OTWT was more effective. In histopathology, OTWT could significantly alleviate the accumulation of renal AGE in T2D mice, thereby improving the structural changes of the kidneys, such as glomerular hypertrophy, glomerular basement membrane thickening and kidney FIbrosis. Conclusions Both WT and OTWT could alleviate the diabetic changes in T2D mice via hypoglycemic, hypolipidemic, anti-oxidative and anti-inflammatory effects, while OTWT was more evident. OTWT could prominently alleviate the accumulation of AGE in the kidneys of T2D mice, thereby ameliorating the renal oxidative stress and inflammatory damage, which was associated with the activation of SIRT1/AMPK pathway.
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Plant-based beverages to interfere with the onset of diabetes may be a promising approach towards type 2 diabetes mellitus (T2DM). The present study investigated the antidiabetic effects of oral consumption of white tea and G. pentaphyllum (Jiaogulan), especially their combination on HFD/STZ-induced T2DM in C57BL/6 mice. White tea and Jiaogulan administration could mitigate glycolipid metabolic disorders in the diabetic mice by different degrees. White tea administration markedly reduced the blood glucose and ameliorated the glucose intolerance compared to the T2DM mice. Moreover, white tea consumption could protect the islet β-cells against oxidative and inflammatory damage, related to Nrf-2 signaling pathway. Jiaogulan prominently attenuated liver lipid accumulation by downregulation SREBPs levels. However, interestingly, when white tea was used in combination with Jiaogulan, these effects were enhanced to a certain extent. In particular, the combination significantly suppressed the hepatic G6Pase expressions by activating AMPK pathway, thus inhibiting gluconeogenesis and improving insulin resistance. On the other hand, the combined formula could regulate the PPARs expressions and ameliorate the hepatic inflammation, further activate the IRS/PI3K/AKT pathway and exert antidiabetic potential. Therefore, it was speculated that the antidiabetic effect of this combination may be associated with the AMPK/PI3K pathways. Our findings might give a sight into the combined use of white tea with Jiaogulan tea as a potential functional beverage or food for preventing T2DM.
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با پیشرفت جامعه و ماشینی شدن زندگی، فعالیت بدنی افراد کمتر شده است و همین عامل سبب می شود با بیماری به نام چاقی دست و پنجه نرم کنند. چاقی اغلب در اثر مصرف غذای زیاد و فعالیت کم به وجود می آید و خطراتی همچون، بیماری های قلبی عروقی، دیابت نوع 2، مشکلات گوارشی، سرطان و ... را به همراه دارد. استفاده از مکمل های چربی سوز با یا بدون ورزش یکی از روش های مرسوم برای مقابله با چاقی می باشد. یکی از این مکمل های پر طرفدار چای ها می باشد. برخی شواهد نشان می دهد مصرف چای قبل از ورزش موجب افزایش چربی سوزی در ورزش می شود. اثرات مصرف آن در طولانی مدت نیز بر کاهش وزن در برخی تحقیقات نشان داده شده است. در این مقاله سعی شده است تا به بررسی اثرات کوتاه مدت و بلند مدت چای (سیاه، اولانگ، سبز و سفید) بر شاخص های چربی سوزی و ترکیب بدن در کنار تمرینات ورزشی طولانی مدت، فعالیت ورزشی کوتاه مدت بر پایه مرور پژوهش‌های صورت گرفته در این زمینه، بپردازیم. مقالات به صورت انگلیسی و فارسی از پایگاه های Science Direct، PubMed، Scopus، Web of Science، Springer، Google Scholar، SID و در دامنه ای از سال ها (1992 تا 2019) مورد بررسی قرار گرفته جمع آوری شده است.
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An overview is given on the manufacture of the different types of tea along with the most important phenolics present in tea and methods of analysis. Compositional data are presented for green, white and black teas. A differentiation of green and black tea by using the ratio between total phenolics and sum of the major catechins seems to be feasible. For white tea there is no general accepted definition. Possible approaches are geographic origin, the botanical variety and the manufacture or the appearance. The differentiation between green and white teas by the ratio mentioned above is not possible. Eswird eine Übersicht über die Teemanufaktur und die resultierenden Arten von Tee gegeben, begleitet von einer Übersicht über einige wichtige Inhaltsstoffe (Flavanole, Zusammenstellung analytischer Methoden zur Bestimmung von (Poly)-phenolen und Daten über grüne, schwarze undweiße Tees). Derzeit scheint eine Differenzierung von grünem und schwarzem Tee über das Flavanol:Gesamtphenolverhältnis möglich. Für weißen Tee gibt es derzeit keine allgemein akzeptierte Definition. Mögliche Ansätze für diese sind die geographische Herkunft, die botanische Varietät oder die Art der Herstellung. Eine Differenzierung durch das Flavanol:Gesamtphenolverhältnis von grünem und weißen Tee ist nicht realistisch.
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Gregoire, Francine M., Cynthia M. Smas, and Hei Sook Sul. Understanding Adipocyte Differentiation. Physiol. Rev. 78: 783–809, 1998. — The adipocyte plays a critical role in energy balance. Adipose tissue growth involves an increase in adipocyte size and the formation of new adipocytes from precursor cells. For the last 20 years, the cellular and molecular mechanisms of adipocyte differentiation have been extensively studied using preadipocyte culture systems. Committed preadipocytes undergo growth arrest and subsequent terminal differentiation into adipocytes. This is accompanied by a dramatic increase in expression of adipocyte genes including adipocyte fatty acid binding protein and lipid-metabolizing enzymes. Characterization of regulatory regions of adipose-specific genes has led to the identification of the transcription factors peroxisome proliferator-activated receptor-γ (PPAR-γ) and CCAAT/enhancer binding protein (C/EBP), which play a key role in the complex transcriptional cascade during adipocyte differentiation. Growth and differentiation of preadipocytes is controlled by communication between individual cells or between cells and the extracellular environment. Various hormones and growth factors that affect adipocyte differentiation in a positive or negative manner have been identified. In addition, components involved in cell-cell or cell-matrix interactions such as preadipocyte factor-1 and extracellular matrix proteins are also pivotal in regulating the differentiation process. Identification of these molecules has yielded clues to the biochemical pathways that ultimately result in transcriptional activation via PPAR-γ and C/EBP. Studies on the regulation of the these transcription factors and the mode of action of various agents that influence adipocyte differentiation will reveal the physiological and pathophysiological mechanisms underlying adipose tissue development.
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Recent advances regarding the biology of adipose tissue have demonstrated that white adipose tissue (WAT) plays a central role in the regulation of energy balance and acts as a secretory/endocrine organ that mediates numerous physiological and pathological processes. Dysregulation of WAT mass causes obesity or lipoatrophy, two disorders associated with life-threatening pathologies, including cardiovascular diseases and diabetes. Alterations in WAT mass result from changes in adipocyte size and/or number. Change in adipocyte number is achieved through a complex interplay between proliferation and differentiation of preadipocytes. Adipocyte differentiation or adipogenesis is a highly controlled process that has been extensively studied for the last 25 years. In vitro preadipocyte culture systems that recapitulate most of the critical aspects of fat cell formation in vivo have allowed a meticulous dissection of the cellular and molecular events involved In the adipogenesis process. The adipogenic transcription factors peroxisome proliferator-activated receptor-gamma and CCAAT/enhancer binding protein-alpha play a key role in the complex transcriptional cascade that occurs during adipogenesis. Hormonal and nutritional signaling affects adipocyte differentiation in a positive or negative manner, and components involved in cell-cell or cell-matrix interactions are also pivotal in regulating the differentiation process. This knowledge provides a basis for understanding the physiological and pathophysiological mechanisms that underlie adipose tissue formation and for the development of novel and sound therapeutic approaches to treat obesity and its related diseases.
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From the established mouse fibroblast line 3T3, we have isolated two clonal sublines that accumulate large amounts of triglyceride fat when the cells are in the resting state. The accumulation is reduced by lipolytic agents. Unless lipid accumulation is allowed to proceed too far, the fatty cells begin to grow again when they are transferred and in this way eliminate most of their lipid.
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The nuclear receptor PPARgamma is a ligand-activated transcription factor that plays an important role in the control of gene expression linked to a variety of physiological processes. PPARgamma was initially characterized as the master regulator for the development of adipose cells. Ligands for PPARgamma include naturally occurring fatty acids and the thiazolidinedione (TZD) class of antidiabetic drugs. Activation of PPARgamma improves insulin sensitivity in rodents and humans through a combination of metabolic actions, including partitioning of lipid stores and the regulation of metabolic and inflammatory mediators termed adipokines. PPARgamma signaling has also been implicated in the control of cell proliferation, atherosclerosis, macrophage function, and immunity. Here, we review recent advances in our understanding of the diverse biological actions of PPARgamma with an eye toward the expanding therapeutic potential of PPARgamma agonist drugs.
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During the last decade, the traditional notion that green tea consumption benefits health has received significant scientific attention and, particularly, the areas of cardiovascular disease and cancer were subject to numerous studies. Due to the ever-growing obesity pandemic, the anti-obesity effects of green tea are being increasingly investigated in cell, animal, and human studies. Green tea, green tea catechins, and epigallocatechin gallate (EGCG) have been demonstrated in cell culture and animal models of obesity to reduce adipocyte differentiation and proliferation, lipogenesis, fat mass, body weight, fat absorption, plasma levels of triglycerides, free fatty acids, cholesterol, glucose, insulin and leptin, as well as to increase beta-oxidation and thermogenesis. Adipose tissue, liver, intestine, and skeletal muscle are target organs of green tea, mediating its anti-obesity effects. Studies conducted with human subjects report reduced body weight and body fat, as well as increased fat oxidation and thermogenesis and thereby confirm findings in cell culture systems and animal models of obesity. There is still a need for well-designed and controlled clinical studies to validate the existing and encouraging human studies. Since EGCG is regarded as the most active component of green tea, its specific effects on obesity should also be investigated in human trials.
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The increased white adipose tissue (WAT) mass associated with obesity is the result of both hyperplasia and hypertrophy of adipocytes. However, the mechanisms controlling adipocyte number are unknown in part because the identity of the physiological adipocyte progenitor cells has not been defined in vivo. In this report, we employ a variety of approaches, including a noninvasive assay for following fat mass reconstitution in vivo, to identify a subpopulation of early adipocyte progenitor cells (Lin(-):CD29(+):CD34(+):Sca-1(+):CD24(+)) resident in adult WAT. When injected into the residual fat pads of A-Zip lipodystrophic mice, these cells reconstitute a normal WAT depot and rescue the diabetic phenotype that develops in these animals. This report provides the identification of an undifferentiated adipocyte precursor subpopulation resident within the adipose tissue stroma that is capable of proliferating and differentiating into an adipose depot in vivo.