Hindawi Publishing Corporation
Evidence-Based Complementary and Alternative Medicine
Volume 2012, Article ID 363845, 9 pages
BerberineImproves InsulinSensitivity by
InhibitingFat Store andAdjusting AdipokinesProfile in
Jing Yang,1JinhuaYin,1,2Hongfei Gao,1LinxinXu,1,2YanWang,1LuXu,2andMing Li2
1First Affiliated Hospital, Shanxi University of Medical, Taiyuan 030001, China
2Endocrine Key Laboratory of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital,
Chinese Academy of Medical Sciences, 1 Shuaifuyuan, Wangfujing, Beijing 100730, China
Correspondence should be addressed to Ming Li, email@example.com
Received 9 October 2011; Revised 29 December 2011; Accepted 29 December 2011
Academic Editor: Hao Xu
Copyright © 2012 Jing Yang et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Berberine is known to inhibit the differentiation of 3T3-L1 cells in vitro, improve glycemic control, and attenuate dyslipidemia in
clinical study. The aim of this study was to investigate the effects of berberine on preadipocytes isolated from human omental fat
and in metabolic syndrome patients treated with berberine for 3 months. We have shown that treatment with 10μM berberine
resulted in a major inhibition of human preadipocyte differentiation and leptin and adiponectin secretion accompanied by
patients showed decrease in their BMI (31.5 ± 3.6 versus 27.4 ± 2.4kg/m2) and leptin levels (8.01 versus 5.12μg/L), as well as
leptin/adiponectin ratio and HOMA-IR. These results suggest that berberine improves insulin sensitivity by inhibiting fat store
and adjusting adipokine profile in human preadipocytes and metabolic syndrome patients.
The metabolic syndrome is a cluster of multiple metabolic
diseases based on obesity and insulin resistance. Obesity
leads to insulin resistance and a proatherogenic state.
abdominal) obesity, is believed to be the main physiological
force resulting in disorders of glucose and lipid metabolism
in metabolic syndrome . However, because of the effects
of insulin in fat cell differentiation and metabolism of
glucose and lipids, patients who are treated by insulin,
sulphonylureas, and thiazolidinediones may suffer from
varying degrees of weight gain. Effects of metformin on body
weight may be based on calorie intake reduction rather than
energy consumption increased. The statins for regulating
lipid metabolism are generally expensive and some of them
have liver toxic side effects. Therefore, the search for a
cost/effective drug that can not only lower blood glucose
and lipids but also reduce weight for metabolic syndrome
treatment has a significant importance.
Berberine is an isoquinoline derivative alkaloid isolated
from many kinds of medicinal herbs, such as Hydrastis
canadensis (goldenseal), Cortex Phellodendri (Huangbai),
and Rhizoma Coptidis (Huanglian). It is safe and cheap
and has been extensively used as an antibacterial drug
. Berberine has been proven to have many other phar-
macological effects including antimicrobial , antitumor
, anti-inflammation , blood glucose lowering ,
and even inhibiting chronic cocaine-induced sensitization
. In one recent single-blind clinical observation, the
study showed that diet supplementation of some natural
substances including berberine was beneficial for correcting
lipid metabolism disorders and reducing cardiovascular risk
factors . However, the body weight reduction effect is
poorly characterized in clinical study.
Pharmacokinetics of berberine indicates that adipose tis-
sue is its main target . Adipose tissue is a huge energy
reserve organ. The excessive proliferation and differentiation
of fat cells can lead to excessive fat accumulation in adipose
2Evidence-Based Complementary and Alternative Medicine
secrete a variety of hormones, named adipokines, through
endocrine, paracrine, and autocrine mechanisms that affect
energy metabolism of the body . It is assumed that unfa-
vorable changes in the secretion of adipokines, considered
as an early symptom of impaired adipose tissue function,
are the potential link between obesity and insulin resis-
tance, influencing the development of metabolic syndrome
. Leptin and adiponectin are the key biomarkers of
adipose tissue. Hyperleptinemia and hypoadiponectinemia
are common in obesity. They reflect increased adiposity
and may contribute to hypertension, dyslipidemia, impaired
glucose metabolism, and proatherogenic state in obesity
and metabolic syndrome [13, 14]. Many studies have been
published on the mechanism of berberine’s effect on adipose
differentiation of mouse 3T3-L1 preadipocytes into fat
cells . In addition, it has also been shown to reduce
leptin and resist secretion  and increase the mRNA
expression of adiponectin . Members in our research
team, Zhang et al. also found berberine-moderated glucose
and lipid metabolism through a multipathway mechanism
that includes AMP-activated protein kinase- (AMPK-) p38
MAPK-GLUT4, JNK pathway, and PPARα pathway in KKAy
mice . These results showed that berberine may have
excellent potential as an agent to prevent metabolic syn-
drome. However, these studies were performed in rodent
models or murine cell lines. The effects of berberine on
human adipose tissue are rarely reported. Due to lack of
well-established human adipocyte model, human primarily
cultured preadipocytes have been particularly useful for
verifying the results obtained from the preadipocyte cell
lines. Thus, in this paper, we presented evidence obtained
from human primarily cultured omental preadipocytes as
well as from metabolic syndrome patients and demonstrated
that berberine improves insulin sensitivity by inhibiting fat
store and adjusting the profile of adipokines.
2.1. Materials. Berberine used in vitro study was purchased
from Sigma Aldrich Co, St. Luis, MO, USA. Oral medication
berberine used in vivo study has Chinese Drug Approval
Number: H.M.L.N., H11022584.
2.2. Adipose Biopsies. Omental adipose tissue biopsies were
obtained from nine patients (3 females, 6 males, age range
22∼47 years) who underwent elective inguinal hernia repair
surgery. None of these patients suffered from endocrine
malignant or chronic inflammatory diseases or severe sys-
temic illnesses or any recent weight change. None were
taking medications known to affect adipose tissue mass or
metabolism. The study was approved by the local ethical
committee. All patients gave their informed consent. On
the day of surgery, all patients fasted for at least 6h pre-
operatively, and all underwent general anesthesia. Adipose
tissue specimens from the omental adipose tissue regions
were obtained within 30–45min after the onset of surgery.
In general, 10–15g of adipose tissue was obtained and trans-
ported to the laboratory in normal saline (transport time
with 10min). Specimens from three patients were used for
cell proliferation experiments and six for cell differentiation
2.3. Cell Culture. The isolation and culture of preadipocytes
was performed according to the method described elsewhere
1mm pieces with ophthalmic scissors. Collagenase digestion
was performed at 37◦C on a shaking platform (200rpm)
for 1 to 3 hours. Next, digest was transferred to filter by
74μm sieve size filter. This procedure was repeated until
the complete digestion was filtered. The cell suspension was
centrifuged at 480g for 5min, and the preadipocyte fraction
was resuspended in growth medium (PromoCell, Germany).
Then cells were counted and cultured in different mediums
at 37◦C in a humidified 5% CO2atmosphere.
2.4. Analysis of Cell Proliferation. 4 × 103preadipocytes/well
were inoculated into 96-well plates and cultured in growth
medium supplemented with varying concentrations of
berberine (0μM, 0.1μM, 1μM, and 10μM). Proliferation
was determined by MTT assay after 1, 2, and 3 days of
culture. Briefly, after culture medium was removed, MTT
(0.5mg/mL, 50μL/well) was added into the plates and
incubated at 37◦C for 4h, followed by the addition of
DMSO (150μL/well), and incubated at 37◦C for 1 hour. The
proliferation values were obtained from the optical density
(OD) measured at 570nm with 650nm as background. Data
are presented as percentage of the untreated controls (0μM
berberine) at each time point.
2.5. Analysis of Cell Differentiation. 5 × 104cells/well cells
were inoculated in 24-well plates. After 48 hours, cells
were induced to differentiate in differentiation medium
(PromoCell, Germany) containing varying concentrations of
berberine (0μM, 0.1μM, 1μM, and 10μM). After 16 days,
the degree of differentiation was determined by Oil-Red-
O staining performed as previously reported . In brief,
medium was removed and cells were washed with PBS twice,
fixed with 3.7% formalin at room temperature for 30min,
added 60% 2-propanol and incubated for 5min, then moved
out 2-propanol and stained cells with Oil-Red-O solution
(Sigma, USA) at room temperature for 10min. Images were
obtained using an Olympus IX70 inverted phase-contrast
microscopy (Olympus, Japan). After staining, the cells were
washed twice with 70% ethanol and dissolved in 2-propanol
containing 4% Nonidet-P40. OD values were measured at
an absorbance of 490nm using a standard microtiter reader
2.6. RT-PCR Analysis. 5 × 105cells/well cells were seeded in
6-well plates. 8 days after differentiation, 10μM berberine
was added in differentiation medium. Cells were harvested
for 24 hours afterwards and mRNAs were extracted with
Trizol reagent (Invitrogen, USA). RNA recovery and quality
were checked by measuring the 260/280nm optical density
ratio and by electrophoresis on 1.5% agarose gel. 1μg of
total RNA from each sample was used for reverse tran-
scription reaction using the TaqMan reverse transcription
Evidence-Based Complementary and Alternative Medicine3
reagents (Applied Biosystems, USA). The expression levels
of peroxisome proliferator-activated receptor γ2 (PPARγ2),
CCAAT enhancer-binding protein α (C/EBPα), lipoprotein
lipase, leptin, and adiponectin were measured using the
following oligonucleotides (Shanghai Biotechnology Engi-
neering Service Co. Ltd., China): 5?-GTG/GGG/CGC/CCC-
AA/TTC/CTT/C-5?primers for β-actin; 5?-ACC/CTG/T-
T/CCG/ATG/AGG/TGT/CTC-5?primers for leptin; 5?-
CT/AAC/CTC/GT-5?primers for adiponectin; 5?-GCG-
AG/AGG/TGG/AAT/AAT-5?primers for PPARγ2; 5?-GCA-
A/CCA/GTT/CCG/GTA/CCC/GT-5?primers for C/EBPα;
/TCC/TCG/TAA/TGG/GTC/AC-5?primers for lipoprotein
lipase. The basic reaction conditions are as follows: DNA
denaturation at 94◦C for 5min; PCR amplification: 94◦C
denaturation for 50sec, specific annealing temperature for
50sec, 72◦C extension for 1min, and final extension also at
72◦C for 8min. To ensure that amplification of these prod-
ucts was within the exponential range, different numbers
of PCR cycles (25–40 cycles) were run. PCR products were
sent to Shanghai Biotechnology Engineering Service Co. Ltd.
for sequence verification. PCR products were analyzed on a
2% agarose gel, and semiquantitative analysis was performed
(quantification with Bio-1D software, France).
2.7. Effects of Berberine on Secreted Proteins in the Human
Preadipocyte Differentiation Process. 105cells/well cells were
inoculated in 12-well plates. Cells were induced with differ-
entiation medium. Beginning on the third day, supernatants
were collected every 2 days and the final collections were
done after 21 days of differentiation. Leptin and adiponectin
tikine, R&D Systems, Germany). The intra- and interassay
CVs for leptin were <3.3% and <5.4%, respectively; the
intra- and interassay CVs for adiponectin were <5.0% and
2.8. Clinical Intervention Study. 41 patients (age ranged 32∼
in this study. 3 of them were initiative to withdraw from
the study on medication 1, 3, and 6 days, and 1 person
lost contact. In the end, 37 people (17 males/20 females)
finished the clinical trials. Metabolic syndrome was defined
according to Chinese Diabetes Society definition set in
2004 . The study had the approval of the local ethical
committee, and informed consent was obtained from all
patients. Patients were treated with berberine 0.3g three
times a day for 12 weeks, and the following indicators
before and after treatment were measured: height, weight,
waist circumference, fasting plasma glucose, fasting insulin,
hemoglobin A1C (HbA1c), triglyceride, cholesterol, LDL
cholesterol, high-density lipoprotein, adiponectin, and lep-
tin. The following were calculated: BMI, Leptin/Adiponectin
index [HOMA-IR = fasting insulin (mIU/L) × fasting
glucose (mmol/L) /22.5].
2.9. Statistical Analysis. Descriptive statistics and analysis
were performed in SPSS 13.0 for Windows (SPSS Inc.
Chicago, IL). t-tests of two independent samples were done
to determine the mean comparison in cell study (test of
homogeneity of variance, such as P < 0.10, line t-test), and
t-test of paired measurement data was done in clinical study
before and after medication. Data of normal distribution
were expressed as means ± the standard deviation. Data of
nonnormal distribution were expressed as median (M) and
quartile (Q1/4). The α level was set at 0.05.
3.1. Omental Preadipocytes and Induced Mature Adipocytes.
Human omental preadipocytes were isolated and primarily
cultured in growth medium. After 3-4 days, these cells
began to show the typical long spindle shape (Figure 1(a))
and started to proliferate. Preadipocytes were induced to
differentiate, and morphological changes can be observed
after 15 days. When preadipocytes gradually mature, their
cytoplasm was filled with lipid droplets, and small lipid
droplets were integrated into big lipid droplets (Figure 1(b)).
Fat droplets in adipocytes can be observed in the cytoplasm
by Oil-Red-O staining (Figure 1(c)).
3.2. Effect of Berberine on Human Preadipocyte Proliferation.
Primary human omental preadipocytes were treated with
different concentrations of berberine and OD values were
measured at day 1, day 2, or day 3. Results show that the
relative OD values are significantly higher when berberine
was added at 0.1μM, 1μM, and 10μM concentrations
compared with the control group (P < 0.05) (Figure 2).
groups (P > 0.05).
3.3. Effect of Berberine on Human Preadipocyte Differentia-
the cell differentiation process, and cells’ morphological
changes through Oil-Red-O staining were observed at day
16. Cell density was reduced judging by the stained color per
increasing drug concentrations at low magnification field of
differentiation and hypertrophy (Figure 3(a)). The staining
intensity was measured. OD values of the berberine groups
than of the control groups, and the decreases determined
were dose dependent (P < 0.05) (Figure 3(b)).
3.4. Effect of Berberine on PPARγ2, Lipoprotein Lipase,
C/EBPα, Leptin, and Adiponectin mRNA Expression. Pre-
adipocytes were induced to differentiate over 8 days, then
10μM berberine was added and cells were harvested for 24
hours. The expression levels of PPARγ2, lipoprotein lipase,
C/EBPα, leptin, and adiponectin were measured by RT-
PCR. For quality control, the resulting PCR products were
sequenced in duplicate and showed >85% homology with
4Evidence-Based Complementary and Alternative Medicine
Figure 1: Representative phase-contrast images of human omental preadipocytes in primary culture and differentiated preadipocytes.
(a) Human omental preadipocytes in primary culture, (b) mature adipocytes induced from preadipocyte differentiation, and (c) mature
adipocytes stained with Oil-Red-O, ×200.
Relative OD value (control (%))
Figure 2: Effect of berberine on human preadipocyte proliferation.
Cells were cultured in growth medium with different concentra-
tions of berberine for 1, 2, and 3 days. At each culture time point,
proliferation capacity was determined by MTT assay. Values are
expressed as percentage of the untreated controls and represent the
mean ± SEM of the three separate experiments in eight replicates.
∗P < 0.05, compared to control at each time point.
GenBank registration sequences. Comparison of the ratio of
the gray degree between the specific gene band and internal
reference β-actin band showed that 10μM of berberine
inhibits PPARγ2, lipoprotein lipase, C/EBPα, adiponectin,
and leptin mRNA expression (Figures 4(a) and 4(b)).
3.5. Effect of Berberine on Leptin and Adiponectin Secretion
during the Process of Preadipocyte Differentiation. When
preadipocytes were cultured with growth medium, a very
low level of leptin protein was detected. However, the levels
did not change with time. No adiponectin secretion can be
medium, the secretion of leptin increased gradually with
time. It increased much more rapidly after day 9 and reached
the peak at day 17∼19. After that, it maintained a high
level of secretion. The secretion of adiponectin was also
differentiation induced, and at day 7, low levels of secretion
can be detected. This was the time when fat cells containing
lipid droplets can be seen under microscope. After 15∼17
days, adiponectin secretion reached its peak; however, it
began to decrease significantly at day 21 (P < 0.05). For the
10μM berberine-treated differentiation medium group, the
levels of leptin and adiponectin secretion were significantly
reduced starting from day 9 and remained low until day 21
(from mid- to terminal stages of differentiation) (Figure 5).
3.6. Effects of Berberine on the Impact Clinical Markers.
Patients with newly diagnosed metabolic syndrome were
treated with berberine for 12 weeks. Their BMI, waist cir-
cumference, fasting plasma glucose, fasting insulin, HbA1c,
triglyceride, total cholesterol, LDL cholesterol, leptin, the
ratio of leptin and adiponectin, and HOMA-IR were mea-
sured before and after the treatment. All of those indexes
showed a decreasing trend, with a significant statistical dif-
ference (P < 0.05–0.01). However, the levels of adiponectin
did not change significantly (Table 1).
gastrointestinal adverse events was mainly constipation (n =
1; percentage, 5%). The adverse effect disappeared when
berberine dosage was decreased from 0.3g three times a day
to 0.2g three times a day. Liver and kidney functions were
monitored in this study. No significant changes of plasma
of berberine treatment (Table 1). None of the patients were
observed with hypoglycemia.
Proliferation and differentiation are two important aspects
in fat tissue development. In our experiment, we have
preadipocytes, promoting cell proliferation. Our result is
Evidence-Based Complementary and Alternative Medicine5
0 μM 0.1 μM 1 μM 10 μM
Figure 3: Effect of berberine on human preadipocyte differentiation. Cells differentiated in the absence or presence of different
concentrations of berberine over 16 days. The degree of differentiation was determined by Oil-Red-O staining. (a) Photomicrographs
representing cells maintained in different concentrations of berberine: (A) control, (B) 0.1μM berberine, (C) 1μM berberine, (D) 10μM
berberine, ×100. (b) Absorbance value representing the mean ± SEM of the three separate experiments in six replicates.∗P < 0.01,
comparison between berberine-treated groups and control group,†P < 0.05, comparison among berberine-treated groups.
consistent with previous studies showing that berberine can
promote the proliferation of mouse 3T3-L1 preadipocyte
. Adult obesity is mainly due to the increased volume
of fat cells which are abnormally hypertrophic . Our
in vitro experiments showed that berberine significantly
inhibited the omental preadipocytes to become mature
Red-O staining. Therefore, berberine has potential clinical
application in reducing visceral fat and controlling central
obesity. It has been reported that fat tissue composed of
a higher amount of small fat cells is more sensitive to
insulin compared with fat tissue with the same lipid content
composed of a small number of large fat cells, and also
the former has very little inflammatory responses . Our
results showed that berberine can promote human fat cell
proliferation and inhibit fat cell enlargement, indicating
that it may be able to reduce inflammation responses,
improve insulin sensitivity of visceral adipose tissue, and
reduce or eliminate the visceral adipose tissue. Moreover,
our in vivo study also showed that, after taking berberine
for three month, patients with metabolic syndrome were
found to reduce their waist circumferences and BMI to
varying degrees. This positive result therefore seems in good
agreement with the in vitro study.
The nuclear receptor PPARγ and members of the C/EBP
family take important roles in adipogenesis , and the
major players are PPARγ2  and C/EBPα . Many
studies have showed that berberine inhibited the mRNA and
protein levels of adipogenesis-related transcription factors
PPARγ2 and C/EBPα [28, 29]. We studied the effect and
transcriptional impact of berberine on human preadipocyte
differentiation. Our result showed that the berberine can
inhibit PPARγ2 and C/EBPα mRNA expression simul-
taneously during the human preadipocyte differentiation
process. Recently, the transcription factors GATA binding
protein 2 and 3 (GATA-2 and GATA-3) have been shown to
be important gate keepers of the differentiation process [30,
31]. Studies from HU et al. showed that berberine increases
expression of GATA-2 and GATA-3 during inhibition of
adipocyte differentiation in both murine cell lines 3T3-L1
and human white preadipocytes cell line. But contradic-
torily, they also found that the differentiation inhibition
mechanisms of berberine appeared to be independent of
PPARγ2 and C/EBPα in that human white preadipocyte cell
line while being dependent on decreasing of PPARγ2 and
C/EBPα gene expression in 3T3-L1 lines [32, 33]. Those
results also seem to contrast with our findings from human
primarily cultured preadipocytes. Since there is still lack
6Evidence-Based Complementary and Alternative Medicine
Ratio of gray degree (versus β-actin)
Figure 4: Effect of berberine on PPARγ2, lipoprotein lipase, C/EBPα, leptin, and adiponectin mRNA expression in differentiated
preadipocytes analyzed using RT-PCR. (a) Digital photos of PCR products in agarose gel. Lane 1: control group, lane 2: 10μM berberine,
representing the mean ± SEM of the three separate experiments in triplicate.∗P < 0.05, compared to control.
of well-characterized human preadipocyte cell lines, further
studies in human primarily cultures are particularly needed
to clarify the results from those cell lines.
Lipoprotein lipase is a kind of glycoprotein synthe-
sized and secreted by fat cells. Current understandings of
lipoprotein lipase’s physiological functions are to decom-
pose chylomicrons and triglycerides into very low-density
triglyceride phospholipids and apolipoproteins and so forth.
We found that berberine reduced lipoprotein lipase mRNA
expression in human fat cells which is consistent with the
recent study by Choi et al. showing that berberine reduces
mouse 3T3-L1 lipoprotein lipase mRNA expression .
As discussed by Kong et al. , oral administration of
berberine in 32 hypercholesterolemia patients for 3 months
reduced serum cholesterol by 29%, triglycerides by 35%, and
LDL cholesterol by 25%. Our clinical study of the effects
of berberine on total cholesterol, triglycerides, and LDL
cholesterol along with analysis of liver and kidney adverse
reactions also indicates that berberine could be a cheap,
Leptin and adiponectin have been shown to play an im-
portant role in insulin resistance. During the process of
Evidence-Based Complementary and Alternative Medicine7
Table 1: The general information and laboratory data of the new diagnosed metabolic syndrome patients at the baseline and 12 weeks after
41.1 ± 7.3
31.5 ± 3.6
146.1 ± 14.9
95.5 ± 8.7
37.28 ± 4.12
48.71 ± 8.12
87.45 ± 4.71
Body mass index (kg/m2)
Waist circumference (cm)
Systolic pressure (mmHg)
Diastolic pressure (mmHg)
Total cholesterol (mM)
High-density lipoprotein cholesterol (mM)
Low-density lipoprotein cholesterol (mM)
Fasting plasma glucose (mM)
Fasting insulin (mIU/L)
Glutamic-pyruvic transaminase (U/L)
γ-Glutamyl transpeptidase (U/L)
t-test of paired measurement data comparisons between two comparing lines before and after medication. Data of nonnormal distribution were described
using the median (M) and quartile (Q1∼Q4).
Basal medium (leptin)
10 μM berberine (leptin)
Differentiation medium (leptin)
Basal medium (adiponectin)
10 μM berberine (adiponectin)
Differentiation medium (adiponectin)
Adiponectin (ng/mL/48 h)
Leptin (pg/mL/48 h)
Figure 5: Effect of berberine on leptin and adiponectin secretion
the mean values of the three separate experiments in triplicate.
preadipocytes differentiation, secretion of leptin and adi-
ponectin showed different kinetics: in the first phase low
levels of leptin secretion can be detected in fat cells, but no
adiponectin secretion can be detected. The amount of leptin
secretion continued to increase in a synchronized fashion
with the differentiation process, while the secretion of
mature and their cytoplasm began to be filled with lipid
droplets. This result suggests that only mature fat cells can
secrete adiponectin which can be used as a specific marker
to determine the maturity of fat cells. In the midstages of
differentiation, secretion of leptin and adiponectin increased
with an increased number of fat cells; however, the rate of
increase in adiponectin was more obvious. In the late stages
of differentiation (at day 17–21), a morphological change
of the cells showed that the majority of cells differentiated
into fat cells with their cytoplasm filled with large lipid
droplets. Oil-Red-O staining showed that lipid content in
the cytoplasm remained at a steady high level. At this point,
leptin secretion remained at high levels, while adiponectin
secretion was seen to show a clearly downward trend. This
difference suggests that fat cells in different fat-storing states
secrete leptin and adiponectin differently, which may also
reflect on their functional differences. The differentiation
stages of fat cells from clinically obese patients may be differ-
ent from normal people. In obese patients, the fat cells may
our differentiation experiment, berberine not only inhibited
the differentiation and maturation of preadipocytes but also
suppressed leptin and adiponectin secretion. This suggests to
us that, in the visceral adipose tissue accumulation process,
berberine has a role in endocrine function regulation and
can promote the reversion of the initial process of fat storing.
Our clinical observation showed that in patients with newly
diagnosed metabolic syndrome the level of leptin dropped
8 Evidence-Based Complementary and Alternative Medicine
significantly with berberine treatment after 3 months. This is
different from results shown in rat studies and may reflect
species differences. This may suggest that berberine has
the potential for anticentral obesity and regulating obesity-
related endocrine dysfunctions, thus achieving a balance
leptin and adiponectin reflects the body’s insulin resistance
. We have confirmed that berberine reduces HOMA-
IR and the ratio of leptin and adiponectin. As it inhibits
PPARγ2 mRNA expression and has more effects on weight
loss and reducing leptin levels, berberine regulates insulin
sensitivity with a mechanism different from the insulin
sensitizer, thiazolidinediones. Thus, berberine provides an
additional way for clinical treatment of metabolic syndrome
and obesity-related diseases. However, our experiment is
only a preliminary study on the mechanisms of effects of
berberine on serum adipokines. A large-scale clinical study is
ideally required to include different population groups and
more experiments concerning the mechanism details.
In conclusion, in order to explore the mechanism of
berberine’s role in improving insulin sensitivity, we used
human adipose tissue as material, focusing on the prolif-
eration, differentiation, and adipokine secretion of human
preadipocytes. We tried to find clues from the in vitro
experiments and then verified them in clinical trial. Our
clinical study has some limitations relative to the random-
ized, placebo-controlled clinical design. However, our result
is in agreement with the findings from previous large sam-
ple, well-designed clinical studies [23, 34], indicating that
berberine improves glucose and lipid metabolism disorders.
cultured preadipocytes as well as in metabolic syndrome
patients, and this was not well characterized in previous
Conflict of Interests
The authors declare that there is no conflict of interests.
The authors thank all the participants. Grants from Key
Laboratory of Endocrinology Ministry of Health and Peking
Union Medical College Hospital, New Star Project of Beijing
Science and Technology (2004A027), and National Natural
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