Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy
open access to scientific and medical research
Pilot study on the additive effects of berberine
and oral type 2 diabetes agents for patients
This article was published in the following Dove Press journal: Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy16 July 2012Number of times this article has been viewed
Background: Suboptimal glycemic control is a common situation in diabetes, regardless
of the wide range of drugs available to reach glycemic targets. Basic research in diabetes is
endeavoring to identify new actives working as insulin savers, use of which could delay the
introduction of injectable insulin or reduce the insulin dose needed. Commonly available as a
nutraceutical, berberine is a potential candidate. Methods and results: Because its low oral bioavailability can be overcome by P-glycoprotein inhibitors like herbal polyphenols, we have tested the nutraceutical combination of Berberis aristata extract and Silybum marianum extract (Berberol®) in type 2 diabetes in terms of its
additive effect when combined with a conventional oral regimen for patients with suboptimal
glycemic control. After 90 days of treatment, the nutraceutical association had a positive effect on glycemic and lipid parameters, significantly reducing glycosylated hemoglobin, basal insulin, homeostatic model assessment of insulin resistance, total and low-density lipoprotein cholesterol, and triglycerides. A relevant effect was also observed in terms of liver function by measuring aspartate transaminase and alanine transaminase. The product had a good safety profile, with distinctive gastrointestinal side effects likely due to its acarbose-like action. Conclusion: Although further studies should be carried out to confirm our data, Berberol could be considered a good candidate as an adjunctive treatment option in diabetes, especially in patients with suboptimal glycemic control. Keywords: berberine, silymarin, glycosylated hemoglobin, diabetes Introduction Diabetes mellitus is recognized as a group of heterogeneous disorders, with common elements of hyperglycemia and glucose intolerance due to insulin deficiency, impaired effectiveness of insulin action, or both. The prevalence of type 2 diabetes increases with age, is increasing worldwide, and its economic impact currently accounts for a significant portion of health care expenditure.1 Injection of long-acting insulin is a common therapeutic approach for patients with type 2 diabetes that is poorly controlled with multiple oral regimens.2 Unfortunately, although insulin use as the mainstay of treatment for diabetes has resulted in favorable treatment outcomes, poor adherence/ compliance continues to be a problem because of fear of insulin or fear of injection, and
this can be associated with poor glycemic control, clinical complications, psychological
comorbidity, poor general well being and health status, and increased mortality risk
in patients with diabetes.3 Last but not least, use of insulin is very often considered to
be the “point of no return” in medical intervention for diabetes. These observations
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Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy 2012:5 213–217
2012 Di Pierro et al, publisher and licensee Dove Medical Press Ltd. This is an Open Access article
which permits unrestricted noncommercial use, provided the original work is properly cited.
suggest a need for implementation of new therapeutic strate-
effect similar to that of metformin,14 even if it likely acts via
gies to delay the need for insulin as far as possible.
a mechanism different from that of metformin.15
Berberine, an isoquinoline alkaloid of the protoberberine
Berberine regulates glucose metabolism via mul-
type and found in an array of plants, has been used in Indian
tiple mechanisms of action. It enhances glucose uptake
and Chinese medicine for many decades. It is present in
by upmodulation of glucose transporter type 4, activates
Hydrastis canadensis (goldenseal), Coptis chinensis (Coptis
5′-AMP-activated protein kinase as a consequence of inhi-
or goldenthread), Berberis aquifolium (the Oregon grape),
bition of mitochondrial function, suppresses adipogenesis
Berberis vulgaris (barberry), and Berberis aristata (tree
by inhibition of peroxisome proliferator-activated receptor
turmeric). Berberine and extracts of berberine have demon-
gamma and C-enhancer-binding protein alpha function, and
strated significant antimicrobial activity against a variety of
decreases intestinal glucose absorption by inhibition of alpha-
organisms, including bacteria, viruses, fungi, protozoans,
glucosidase.16 However, despite these functions, berberine
helminths, and chlamydia. The predominant clinical uses of
has poor oral bioavailability.17 In humans, this appears to
berberine, at least in the recent past, have included bacterial
be due to a P-glycoprotein-mediated gut extrusion process18
diarrhea and intestinal parasite infections.4
and substantial excretion in bile.19 P-glycoprotein seems to
More recently, clinical research on berberine has revealed
decrease the amount of berberine able to cross enterocytes
novel pharmacological properties and multiple therapeutic
by about 90%,20 suggesting that inhibition of P-glycoprotein
applications, mainly concerning hypercholesterolemia
could potentially improve its oral poor bioavailability.
and diabetes.5 With regard to the lipid profile, berberine
Among the potential P-glycoprotein inhibitors, silymarin
upregulates low-density lipoprotein receptor expression
from Silybum marianum could be a good candidate due to its
independent of sterol regulatory element-binding proteins,
very poor oral bioavailability and its good safety profile.21
but dependent on extracellular signal-regulated kinases and
Therefore, we investigated the activity of a combination
c-Jun N-terminal kinase activation, leading to reductions in
of berberine and silymarin when added to oral hypoglycemic
total cholesterol and low-density lipoprotein cholesterol of
regimens for patients with suboptimal glycemic control. Our
about 30% and 25%, respectively. This upmodulation occurs
aim was to evaluate the impact of this approach on body mass
via a post-transcriptional mechanism that stabilizes mRNA
index, hyperglycemia, hypercholesterolemia, triglyceride
and enables berberine to act as a cholesterol-lowering drug
levels, and liver enzymes in patients with type 2 diabetes.
via a mechanism of action different from that of the statins.6 In addition to its cholesterol-lowering properties, berberine
Materials and methods
reduces triglycerides by about 35%. These effects on the lipid
The study was performed in routine clinical practice in
profile have been observed in both animals and humans.6,7
accordance with international guidelines and in line with
Berberine also has an important additive effect in the pres-
the principles outlined in the Declaration of Helsinki,
ence of statins.8 This is likely due to the ability of berberine to
so approval from the local ethics board was not required.
downmodulate proprotein convertase subtilisin/kexin type 9,
This study was carried out in a single center in Italy
a protein which reduces the cholesterol-lowering properties
where it is not mandatory to obtain ethical approval when
of statins.9 This effect of berberine could be relevant when
p erforming experiments involving nutraceutical products.
treating patients with suboptimal control of hypercholes-
Twenty-six patients diagnosed with type 2 diabetes were
terolemia despite receiving high doses of statins. Due to
enrolled. The patient demographics are shown in Table 1.
this additive effect, it is quite common to find nutritional
Twenty-two of the 26 patients completed the study, with
supplements containing berberine10 along with a natural
four dropouts as a result of gastrointestinal discomfort and/
source of lovastatin (ie, Monascus purpureus).11 However,
these products do not take into consideration the poor stan-dardization of the raw materials12 and the risk to consumers
Table 1 Demographic characteristics of the 22 patients who
due to the possible presence of mycotoxic contaminants
Berberine has also been shown to be effective in the
Males n = 17 Females n = 5
treatment of diabetes, in which it significantly decreases
glycosylated hemoglobin (HbA ), fasting blood glucose, and
postprandial blood glucose. In this respect, berberine has an
Note: All values for ages and weight are expressed as the median ± standard deviation. submit your manuscript |
Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy 2012:5
The main inclusion criteria were stable (for at least
demonstrated to be a valid addon treatment option for
6 months) but suboptimal glycemic control (HbA 7.5%–9.5%),
patients with type 2 diabetes and suboptimal glycemic
body mass index . 22 kg/m2, age 25–75 years, and a negative
control. As shown in Table 2, a significant reduction was
pregnancy test for female patients. All patients had suboptimal
observed in HbA , basal insulin, total cholesterol, low-
glycemic control despite use of the following drugs, unchanged
density lipoprotein cholesterol, triglycerides, HOMA-R
at least in the last 3 months: metformin (n = 20), incretins (n = 4), (homeostatic model assessment for insulin resistance, cal-sulfonylureas (n = 14), glitazones (n = 3), and insulin (n = 5). culated as glucose × insulin/405, where glucose is expressed Twenty patients were also receiving antihypertensive drugs, and
as mg/dL and insulin as µU/mL), and alanine transaminase.
13 were receiving anticoagulant therapy. As regards the lipid pro-
Aspartate transaminase also showed a downwards trend.
file, 12 patients were receiving statins, 1 was receiving a fibrate
There were no significant changes in high-density lipopro-
whereas 5, previously under treatment with statins, had inter-
tein cholesterol, fasting glucose, body mass index, weight,
rupted the therapy due to unwanted effects, mainly myalgia.
Exclusion criteria were moderate to severe liver
dysfunction (serum alanine aminotransferase . 120 IU/L and
Discussion
aspartate aminotransferase . 80 IU/L), abnormal renal func-
Four of the 26 patients diagnosed with type 2 diabetes and
tion (serum creatinine . 115 µmol/L), severe heart failure suboptimal glycemic control who enrolled in this study (New York Heart Association Class III or greater), history of
dropped out, leaving data for the 22 patients who com-
acute diabetic complications, including diabetic ketoacidosis
pleted the study. We investigated the clinical effects of oral
or hyperosmolar hyperglycemic nonketotic coma, psychiatric
treatment using a nutraceutical combination of B. aristata
disease, severe infection, pregnancy or planning for preg-
extract (containing 85% berberine) and S. marianum extract.
nancy, and fasting plasma glucose $ 200 mg/dL.
The latter ingredient is included with the aim of enhancing
All patients received addon nutraceutical therapy, ie,
the oral bioavailability of berberine, mostly by reducing
Berberol® (PharmExtracta, Pontenure, Italy), an oral tablet
P-glycoprotein activity in the gut. To be eligible for entry
containing 588 mg of B. aristata extract titered as 85% ber-
into this study, patients had to have had suboptimal glycemic
berine and 105 mg of S. marianum extract titered as .60%
control (HbA 7.5%–9.5%) unchanged for at least 3 months
flavonolignans. The product, in agreement with the Italian
despite at least 6 months of treatment with a multidrug
legislation (law number 169/2004) had been notified to the
r egimen. According to the international guidelines, HbA
Minister of Health in 2010 (E10 40753Y) and registered
values in this range are linked with an increased risk of
as a food supplement, with both its actives (standardized
developing microvascular and macrovascular complications,
extracts of B. aristata and S. marianum) belonging to the list of botanicals approved as nutraceuticals and its excipients all
Table 2 Effect of adjunctive Berberol therapy after 90 days of
being food grade. The patients took two tablets per day on an
treatment in 22 patients with type 2 diabetes and suboptimal
empty stomach in the late evening for the 90-day duration of
the study. Berberol was manufactured by SIIT (Trezzano S/N,
Parameter P value
Milan, Italy). The two actives, ie, B. aristata extract and S. marianum extract, were provided, respectively, by SIIT and
Indena, both located in Milano, Italy.
The statistical analysis was performed using SPSS 12.0
for Windows (SPSS Inc, Chicago, IL). Statistical differ-
ences between baseline and different time points were
analyzed using the nonparametric paired t-test. The α level HOMA-R
Notes: All values are expressed as the median ± standard deviation at baseline (t = 0) and after 90 days (t = 90) of daily therapy. Δ% corresponds to the difference
(percent) between t = 0 and t = 90. Abbreviations: BI, basal insulin; FG, fasting glucose; HOMA-R, homeostatic model
Berberol containing extracts of B. aristata and S. marianum
assessment of insulin resistance (FG × BI/405); LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; HbA , glycosylated
extract, dosed at two tablets daily for 90 days, was
hemoglobin; ns, not statistically significant; TC, total cholesterol.
Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy 2012:5
submit your manuscript
and all possible medical effort should be made to reduce
Conclusion
HbA below 7%.22 Use of injectable insulin should be
Berberol is a nutraceutical combination of highly standard-
delayed as long as possible using oral insulin-saving drug
ized herbal extracts of B. aristata and S. marianum titered,
cocktails. The basis for using such cocktails, precisely estab-
respectively, as 85% berberine and .60% flavanolignans.
lished on the basis of the metabolic features of a patient, have
Berberol seems to have positive effects in patients with type 2
to be considered carefully, not only because of the very poor
diabetes and suboptimal glycemic control when given orally
patient compliance with insulin injections, but also because
in addition to a conventional regimen (ie, metformin, dipep-
delaying insulin therapy should spare endogenous insulin
tidyl peptidase-4 inhibitors, glitazones, acarbose or insulin,
alone or as multidrug therapy). Berberol seems to improve
In patients with suboptimal glycemic control, we
the cholesterol-lowering properties of statins, and has a posi-
observed an HbA reduction of about 0.85% after
tive effect on liver enzymes. Treatment seems to be safe and
3 months of treatment with Berberol, which was maintained
tolerated at the doses tested, with minimal unwanted effects,
after 6 months of treatment (data not shown). Such a
which resolve on cessation of treatment without any further
percentage reduction is comparable with that normally
consequences. The results of our pilot study performed in
obtained in patients treated with acarbose, dipeptidyl
26 patients need confirmation by larger trials and with better
peptidase-4 inhibitors (sitagliptin, vildagliptin, saxagliptin),
definition of the diabetic patients enrolled. Allowing for these
or glitazones, used alone or adjunctive to metformin, to
limitations, Berberol can still be considered as a potential
oral nutraceutical suitable for use in addition to conventional
We did not modify any drug or treatment protocol estab-
therapy for type 2 diabetes, with the aim of ameliorating
lished before starting treatment with Berberol in any of the
suboptimal glycemic control as a strategy for postponing
22 patients who completed the study. At the same time,
no modifications in terms of food intake or lifestyle were suggested or adopted before or during the trial, and this is
Disclosure
reflected by the minimal changes in body weight and waist
FDP developed and has patented the Berberol used in
A possible mechanism of action of Berberol could be
its ability to increase insulin sensitivity, as shown by the
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Education: Ph.D. Chemistry - Rennselaer Polytechnic Institute, 1967, B. A. Chemistry - Cornell University, 1963 Career Highlights: One of four Hoechst Celanese Research Fellows Led the teams that invented and commercialized high Invented high modulus, low shrinkage polyester tire cord Led the teams that invented Vectra Liquid Crystalline Polyester, played leadership role in product co