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Shanghai Clinical Center for Endocrine and Metabolic Diseases and Division of Endocrine and Metabolic Diseases (Y.Z., X.L., N.Z., L.H., J.H., G.N.), E-Institutes, Shanghai Universities, Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People’s Republic of China; Department of Endocrinology (D.Z., M.W.), Chang-Hai Hospital, the Second Military Medical University, Shanghai 200433, People’s Republic of China; Department of Endocrinology (W.L., P.W.), Ren-Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, People’s Republic of China; and Department of Endocrinology (J.Y., G.R.), Min-Hang Hospital, Shanghai 201100, People’s Republic of China
Address all correspondence and requests for reprints to: Guang Ning, M.D., Ph.D., Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrinology and Metabolism, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 RuiJin 2nd Road, Shanghai 200025, People’s Republic of China. E-mail: guangning{at}medmail.com.cn.
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Abstract |
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 Top Abstract IntroductionPatients and MethodsResultsDiscussionAppendixReferences |
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Objective: The objective of the study was to evaluate the efficacy and safety of berberine in the treatment of type 2 diabetic patients with dyslipidemia.
Design: One hundred sixteen patients with type 2 diabetes and dyslipidemia were randomly allocated to receive berberine (1.0 g daily) and the placebo for 3 months. The primary outcomes were changes in plasma glucose and serum lipid concentrations. Glucose disposal rate (GDR) was measured using a hyperinsulinemic euglycemic clamp to assess insulin sensitivity.
Results: In the berberine group, fasting and postload plasma glucose decreased from 7.0 ± 0.8 to 5.6 ± 0.9 and from 12.0 ± 2.7 to 8.9 ± 2.8 mM/liter, HbA1c from 7.5 ± 1.0% to 6.6 ± 0.7%, triglyceride from 2.51 ± 2.04 to 1.61 ± 1.10 mM/liter, total cholesterol from 5.31 ± 0.98 to 4.35 ± 0.96 mM/liter, and low-density lipoprotein-cholesterol from 3.23 ± 0.81 to 2.55 ± 0.77 mM/liter, with all parameters differing from placebo significantly (P < 0.0001, P < 0.0001, P < 0.0001, P = 0.001, P < 0.0001, and P <0.0001, respectively). The glucose disposal rate was increased after berberine treatment (P = 0.037), although no significant change was found between berberine and placebo groups (P = 0.063). Mild to moderate constipation was observed in five participants in the berberine group.
Conclusions: Berberine is effective and safe in the treatment of type 2 diabetes and dyslipidemia.
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Introduction |
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Berberine, a natural plant alkaloid (Fig. 1
) isolated from the Chinese herb, Coptis chinensis (Huanglian), is commonly used for diarrhea, and a potential glucose-lowering effect has been noted (4). In vitro and in vivo studies subsequently showed that berberine has potentially beneficial effects in the treatment of diabetes and obesity. Berberine can reduce body weight and cause a significant improvement in glucose tolerance in db/db mice and high-fat-fed Wistar rats (5). Berberine may increase glucose-stimulated insulin secretion and proliferation in Min6 cells (6) and inhibit 
-glucosidase activities and reduce glucose absorption in Caco-2 cell (7). Berberine promoted glucose uptake in HepG2 and 3T3-L1 cells independent of insulin action (8, 9) and improved glucose metabolism via glycolysis (10). Berberine also facilitated insulin secretion in HIT-T15 cells and murine pancreatic islets in vitro and in BALB/C mice (11).
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All these clinical studies were open and nonplacebo-controlled. Insulin sensitivity changes have still not been carefully investigated. Therefore, in the present study, we performed a randomized, double-blind, placebo-controlled trial in four centers to evaluate the efficacy and safety of berberine in the treatment of diabetes and dyslipidemia.
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Patients and Methods |
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The study was a randomized, double-blind, placebo-controlled and multiple-center trial consisting of a screening visit, a 2-wk run-in, and a 3-month treatment period. The study was approved by the Institutional Review Board of Ruijin Hospital, Shanghai Jiao-Tong University School of Medicine, and written informed consent was obtained from each patient. The study was conducted in accordance with the principles of the Declaration of Helsinki. The registration number is NCT00462046 (clinicaltrials.gov).
We recruited study participants between May 2005 and May 2006 from the Rui-Jin Hospital, Ren-Ji Hospital, and Min-Hang Hospital of Shanghai Jiao-Tong University School of Medicine and the Changhai Hospital of the Second Military Medical University in Shanghai. Initial screening included a medical history, physical examination, renal and hepatic function, serum lipid concentrations, serum electrolytes, blood counts and urinary analysis, and a 75-g oral glucose tolerance test (OGTT). During the 2-wk run-in period, 152 recently diagnosed type 2 diabetic patients who had not received previous pharmacological treatment were instructed in diet and exercise. Thirty-six patients were excluded because of plasma glucose concentrations 8 mmol/liter or greater and/or a 2-h OGTT plasma glucose concentration 
17 mmol/liter. The remaining 116 patients were randomly assigned to receive double-blind berberine or placebo (Fig. 2). Randomization was performed centrally and was concealed and stratified in blocks of four. In 116 patients, six were lost after randomization without any visits and four dropped out with one or two visits, including one patient completing the first visit from placebo and two and one completing the second visits from the placebo and berberine groups, respectively. A total of 110 patients (94.8%), including those four who dropped out were analyzed for the intention-to-treat efficacy.
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Eligibility criteria were: 1) age of 25–70 yr; 2) newly diagnosed type 2 diabetes according to the 1999 World Health Organization criteria: fasting plasma glucose 7 mmol/liter or greater and/or 2-h OGTT 11.1 mmol/liter or greater (14) and fasting plasma glucose less than 8 mmol/liter; 3) dyslipidemia with triglycerides greater than 150 mg/dl (1.70 mmol/liter), total cholesterol greater than 200 mg/dl (5.16 mmol/liter), and/or low-density lipoprotein (LDL)-cholesterol (c) greater than 100 mg/dl (2.58 mmol/liter) according to the National Cholesterol Education Program’s Adult Treatment Panel III (15) without previous treatment; and 4) body mass index (BMI) 19–40 kg/m2. The exclusion criteria were: 1) moderate or severe liver dysfunction, including serum alanine aminotransferase greater than 120 IU/liter, aspartate aminotransaminase greater than 80 IU/liter, and abnormal renal function (serum creatinine greater than 115 µmol/liter); 2) severe dysfunction of the heart, New York Heart Association class phase III or greater; 3) histories of acute diabetic complications including diabetic ketoacidosis or hyperosmolar hyperglycemic nonketotic coma; 4) psychiatric disease or severe infection; 5) pregnancy or planned pregnancy; 6) present or previous use of drugs for treatment of diabetes or dyslipidemia; and 7) fasting plasma glucose 8 mmol/liter or greater and/or postload plasma glucose concentration 17 mmol/liter or greater after a 2-wk run-in.
Treatment
Patients were randomized to receive berberine (0.5 g, twice daily) or placebo prepared in indistinguishable tablets. A dose reduction to 0.25 g twice daily was suggested whenever the constipation occurred and lasted more than 2 wk. The berberine and placebo tablets were provided by Huashi Pharmaceutical Inc. (Shanghai, China). The berberine is extracted from rhizomes of Coptis chinensis Franch with acidic water (0.3% H2SO4) soaking and chromatographic purification and had a purity 97% or greater.
Clinical and biochemical measurements
Patients visits were studied between 0700 to 0800 h after an overnight fast of 10–12 h. Date of birth, smoking, alcohol consumption, and past medical history were assessed. Height and weight (light clothes and without shoes), waist and hip circumference, and seated blood pressure (measured on the patient’s nondominant arm supported at heart level) were determined by a senior physician (16). Biochemical measurements of serum lipids, glycated hemoglobin (HbA1c), and insulin were performed in a central laboratory (Shanghai Institute of Endocrinology and Metabolism, Shanghai, China). All patients were required to refrain from alcohol, cigarettes, and heavy physical exercise for at least 1 wk before obtaining blood samples for biochemical measurement and performing the 75-g OGTT. Women were studied in the follicular phase of the menstrual cycle. Glucose was measured immediately using an enzymatic method (CX-7 biochemical autoanalyzer; Beckman Brea, CA). Serum insulin was measured using a double-antibody RIA (Diagnostic Systems Laboratories, Webster, TX). Serum total cholesterol and triglycerides were measured by enzymatic methods (Beckman Coulter Inc., Fullerton, CA). High-density lipoprotein (HDL)-c and LDL-c were determined by immunoinhibition methods (HDL-c, LDL-c Direct; Wake Pure Chemical Industries Ltd. GmbH, Neuss, Germany). HbA1c was measured by HPLC using a variant hemoglobin HbA1c assay (Bio-Rad Laboratories, Hercules, CA). Serum IL-6 was measured using ELISA kits (R&D Systems, Minneapolis, MN) and high-sensitivity C-reactive protein (CRP) using ELISA kits (Biocheck Inc., Foster, CA).
Hyperinsulinemic euglycemic clamp
The hyperinsulinemic euglycemic clamp studies were performed in one center (Rui-Jin Hospital), and the participants randomly selected from four centers were all invited to receive clamp examination in Rui-Jin Hospital. A total of 54 patients were randomly selected for clamp assessment of insulin sensitivity, performed 6–8 d after OGTT as described previously (17, 18, 19). A small polyethylene catheter was placed in an antecubital vein for blood sampling. A second catheter was placed in a vein in the contralateral forearm for infusion of insulin and 20% dextrose solution. After a 30- to 45-min stabilization period, a 10-min priming insulin infusion was administered, followed by a constant infusion of 60 mU/m2 surface area per minute over 140 min. Twenty percent glucose was infused at a variable rate beginning 4 min after initiation of the insulin infusion to maintain blood glucose concentrations at 5.0–5.5 mmol/liter. During the clamp, blood glucose levels were repeatedly measured with a glucose analyzer (Biosen 5130; Neckar Healthcare Co. Ltd., Magdeburg, Germany). Blood samples for insulin measurement were collected at 10-min intervals. The glucose disposal rate (GDR; milligrams per kilogram per minute), defined as the amount of glucose required to maintain stable blood glucose concentrations during the last 30 min of the clamping, was used to evaluate insulin resistance.
Evaluation and outcomes
Study assessments were performed at 0, 1, 2, and 3 months. Fasting plasma glucose was checked at each visit and serum total cholesterol, triglycerides, HDL-c, and LDL-c were checked at 0, 1, and 3 months. OGTT, HbA1c measurement, and hyperinsulinemic euglycemic clamp were performed at 0 and 3 months.
The primary efficacy outcome was the change in fasting glucose and 2-h OGTT plasma glucose, total cholesterol, triglycerides, HDL-c LDL-c, HbA1c levels, and GDR. Secondary efficacy outcome was the change in BMI and blood pressures.
Statistical analysis
This study was designed in accordance with a predetermined statistical analysis plan. A sample size of 60 patients in each of the two study groups, with a dropout rate up to 10%, was planned to provide a 90% power to detect a 20% or greater (with 95% confidence intervals, = 0.05, β = 0.1) reduction in fasting plasma glucose concentrations (the primary end point variable) in the berberine group, compared with the placebo group after 3 months at the end of the study.
Statistical analysis was performed using the SPSS 10.0 system (SPSS Inc., Chicago, IL), and data are presented as mean ± SD. Logarithmic transformation was used for IL-6 and CRP because of the high degree of skewing. Within-group comparisons were performed with paired-sample t tests to evaluate differences from baseline in each group. Independent-sample t test and the analysis of covariance (ANCOVA) analysis with a model that included the baseline value of the dependent variable as a covariate were also used for comparison between groups.
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Results |
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Patients were middle-aged Chinese living in the Shanghai region. Of 116 randomized patients, 106 completed the study, four dropped out with one or two visits, and six were lost without any visits. The data of 110 participants including those four who dropped out were analyzed as shown in Table 1. The baseline variables are not significantly different between the berberine and placebo groups.
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As compared with subjects who received placebo, those receiving berberine had a significant improvement in fasting plasma glucose and 2-h OGTT plasma glucose, HbA1c, triglyceride, total cholesterol, and LDL-c. Fasting plasma glucose decreased from 7.0 ± 0.8 to 5.6 ± 0.9 mM/liter with berberine and decreased from 6.8 ± 0.9 to 6.4 ± 1.6 mM/liter with placebo (Fig. 3B), with corresponding falls in 2-h glucose from 12.0 ± 2.7 to 8.9 ± 2.8 vs. 12.2 ± 2.4 to 11.0 ± 2.8 and in HbA1c from 7.5 ± 1.0 to 6.6 ± 0.7% vs. from 7.6 ± 1.2 to 7.3 ± 1.1%, with all parameters differing significantly (Table 1
).
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The ANCOVA analysis showed that serum total cholesterol, triglycerides, and LDL-c concentrations in berberine group were significantly reduced as compared with the changes in placebo group (P < 0.0001, P = 0.001, P < 0.0001, respectively). Serum total cholesterol, triglycerides, and LDL-c concentrations were reduced from 1 month (P < 0.0001) as compared with the baseline, whereas no change was found in placebo group at 1 and 3 months (Fig. 3, C–E).
Fifty-four patients, of whom 28 were from the berberine group and 26 from the placebo group, received hyperinsulinemic euglycemic clamp tests at baseline. Forty-eight patients were available for repeat clamp tests at 3 months, of whom 27 (15 males, 12 females) were from the berberine group and 21 (11 males, 10 females) from the placebo group. Serum insulin levels during the fasting condition and hyperinsulinemic phase (120–150 min) of the clamp tests were 7.93 ± 6.57 and 113.38 ± 55.15 µIU/ml, respectively, at baseline and 9.08 ± 5.95 and 103.32 ± 52.77 µIU/ml, respectively, at the end of the study in the berberine group and 10.52 ± 7.41 and 107.90 ± 43.92 µIU/ml, respectively, at baseline and 10.55 ± 5.66 and 108.85 ± 47.01 µIU/ml, respectively, at the end of the study in the placebo group. No significant difference was found between these two groups. After treatment, the GDR was significantly increased in the berberine group (6.56 ± 2.42 vs. 7.42 ± 2.37 mg/kg·min, P = 0.037), whereas no change was found in the placebo group (5.98 ± 2.46 vs. 6.06 ± 2.21 mg/kg·min, P = 0.86) (Fig. 4). Similar changes were found in the homeostasis model assessment for insulin resistance (HOMA-IR) values (Table 1). With adjustment of body weight change by ANCOVA analysis, HOMA-IR was still reduced in the berberine-treated group (P = 0.025), whereas no significant change was found in the placebo group (P = 0.936), which implied that the change of HOMA-IR values in the berberine group were not caused by the change of body weight. However, ANCOVA analysis showed that the GDR at 3 months was not significantly different between the berberine and placebo groups (P = 0.063).
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Body weight decreased from 68.7 ± 11.3 to 66.4 ± 11.8 kg with berberine, a significantly greater fall than that from 71.8 ± 11.2 to 70.5 ± 11.0 kg in the placebo group (Fig. 3A). A greater reduction of BMI was also found at 3 months in the berberine group than in the placebo group (P = 0.021) (Table 1).
Systolic and diastolic blood pressure decreased from 124 ± 14 to 117 ± 15 and from 81 ± 9 to 77 ± 11 mm Hg in those treated with berberine, exceeding the fall from 126 ± 15 to 123 ± 14 and from 83 ± 8 to 80 ± 9 mm Hg with placebo (Table 1).
IL-6 concentrations were significantly reduced at 3 months in the berberine group either as compared with baseline (P = 0.030) or placebo (P = 0.010). CRP concentrations at 3 months did not differ between the berberine and placebo groups (P = 0.256) (Table 1).
Safety
During the period of study, safety parameters including renal and hepatic function, serum electrolytes, blood counts, and urinary analysis were assessed. Any side effects were obtained and recorded in case report form from each patient. No serious adverse events occurred. Mild to moderate constipation occurred in five participants receiving berberine and one participant in the placebo group. However, the frequency of constipation was not significantly different between the berberine and placebo groups (P = 0.207). Among them, three participants in the berberine group and one in the placebo group relieved without dose reduction, and two patients with mild constipation received a reduction of dose of berberine to 0.25 g twice daily. No episode of hypoglycemia was reported.
Serum alanine aminotransferase, aspartate aminotransaminase, and 
-glutamyl transpeptidase were significantly reduced in the berberine group at 3 month as compared with baseline (30 ± 21 vs. 22 ± 14 IU/liter, P = 0.001; 26 ± 12 vs. 22 ± 7 IU/liter, P = 0.006; 34 ± 20 vs. 30 ± 24 IU/liter, P = 0.053, respectively).
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Discussion |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendixReferences |
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Based on these previous in vitro and in vivo studies, we performed a randomized, double-blind, and placebo-controlled trial to investigate the efficacy and safety of berberine in treatment of persons with diabetes and dyslipidemia, major components of the metabolic syndrome. Berberine had a robust glucose-lowering effect by significantly reducing fasting and postprandial plasma glucose by 1.4 and 3.1 mmol/liter, respectively, at 3 months and HbA1c by 0.9% from the initial levels of 7.5%. The decline in HbA1c achieved with berberine is fully comparable with that with existing pharmacologic products used in treatment of type 2 diabetes (21).
However, the GDR, HOMA values, and serum fasting and postprandial insulin concentrations were not significantly different between the berberine and placebo groups at 3 months, which indicates that insulin sensitivity was only partially improved by berberine due to a trend identified (P = 0.063 for GDR). Furthermore, the GDR increase was observed in berberine group at 3 month as compared with baseline (P = 0.037).
An 18% reduction of serum cholesterol, 35.9% of triglycerides and 21% of LDL-c were achieved in type 2 diabetic patients after a 3-month treatment, which is in accordance with the report of Kong et al. (20) in an open clinical trial. They found berberine up-regulated LDL receptor expression independent of sterol regulatory element binding protein but dependent on ERK activation in human hepatoma cells, whereas our current findings indicate that berberine is more effective in reducing serum triglycerides than cholesterol concentrations, which is similar to fibrates (22). In addition, we also observed that systolic and diastolic blood pressures were significantly reduced with berberine by 7 and 5 mm Hg, respectively (P = 0.001 and P = 0.005, respectively). Modest weight loss was demonstrated, unlikely in itself sufficient to explain the metabolic benefits of the agent, although a clinically favorable finding.
The precise mechanism of berberine in glucose-lowering action has not been fully understood. Lee et al. (5) reported that berberine improved insulin resistance in db/db mice and high fat-fed rats. Berberine can activate AMP-activated protein kinase in 3T3-L1 adipocytes and L6 myotubes and facilitate GLUT4 translocation in L6 myotubes in a phosphatidylinositol 3-kinase-independent manner. Yin et al. (8) and Zhou et al. (9) reported that berberine promoted glucose uptake in HepG2 and 3T3-L1 cells independent of insulin action. In addition, berberine can effectively inhibit sucrase and maltase activities to the same extent as acarbose does in Caco-2 intestinal cells and possibly inhibit -glucosidase activities to reduce glucose absorption (7). In the present study, we also found a significant reduction of serum IL-6 in the berberine group as compared with the control. It indicates that a reduction of inflammation could also be involved in insulin sensitivity improvement in the berberine-treated patients (2, 23, 24).
Berberine cannot provide adequate single drug therapy for all diabetic patients because the patients in the present study had relatively mild diabetes; however, it may be at least useful as an adjuvant to standard therapy.
With regard to the safety, berberine does not have any toxicity at present doses in clinical use. The major side effects can result from overdose, including mild gastrointestinal discomfort in rare cases (20). The pharmacokinetics of berberine was studied in rats (25). Berberine reached the peak concentrations at 2 h after oral administration, declined within 12 h, and then maintained at a very low concentration for 48 h. However, the area under curve and the peak concentrations of its metabolites were much higher. It suggests that blood clearance of berberine is very quick and that its biotransformation in the liver is rapid and substantial, allowing for immediate circulation of its metabolites in the body. In our present study, we found that serum berberine concentrations were 6.1 ± 4.9 ng/ml in the berberine group at the end of the study. It suggests that berberine is rapidly metabolized or/and poorly absorbed in the gastrointestinal tract. So the regulation of gut microflora could be a novel mechanism for berberine to act in antihyperglycemia and antidyslipidemia.
Given the benefits of berberine in lowering blood glucose, lipids, body weight, and blood pressures, we speculate that berberine may be used for patients with type 2 diabetes and metabolic syndrome. Long-term study with a larger sample size is needed to confirm these findings.
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Appendix |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendixReferences |
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Acknowledgments |
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Footnotes |
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Disclosure Statement: The authors have no conflicts of interests.
First Published Online April 8, 2008
1 Y.Z. and X.L. contributed equally to this work. 
Abbreviations: ANCOVA, Analysis of covariance; BMI, body mass index; c, cholesterol; CRP, C-reactive protein; HbA1c, glycated hemoglobin; HDL, high-density lipoprotein; HOMA-IR, homeostasis model assessment for insulin resistance; LDL, low-density lipoprotein; OGTT, oral glucose tolerance test.
Received October 29, 2007.
Accepted April 1, 2008.
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References |
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, reasons for early stop in placebo group: one had higher fasting plasma glucose concentrations (14.5 mmol/liter), two moved during the follow-up, and five had personal conflicts.
) and placebo (
). Data displayed as means ± SE. *, P < 0.0001 after 1, 2, or 3 months treatment vs. before treatment within each group.
, P value refers to comparison between before vs. after treatment within each group.