Synthesis and anti-hyperglycemic activity of hesperidin derivatives

Article abstract of DOI:10.1016/j.bmcl.2012.09.049

A series of hesperidin derivatives were prepared and identified by IR, ¹H NMR, and MS spectra. These compounds were evaluated in vitro and in vivo based on α-glucosidase inhibition, glucose consumption of HepG2 cells, and blood glucose level in streptozotocin-induced diabetic mice. The results revealed that all the compounds exhibited anti-hyperglycemic activities. The inhibition at 10^-3 M of compounds 3 and 7a on α-glucosidase were 55.02% and 53.34%, respectively, as compared to 54.80% by acarbose. Treated by compound 3 and the reference drug metformin, glucose consumption of HepG2 cell were 1.78 and 2.11 mM, respectively. After the streptozotocin-induced diabetic mice were oral administrated with compound 3 at 100 mg kg^-1 d^-1 for 10 days, the blood glucose level of 3 treated mice (13.23 mM, P <0.05) showed significant difference when compared to model control (23.03 mM). Thus, compound 3 exhibited promising anti-hyperglycemic activity.

Full text of DOI:10.1016/j.bmcl.2012.09.049

Bioorganic & Medicinal Chemistry Letters 22 (2012) 7194–7197
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and anti-hyperglycemic activity of hesperidin derivatives
Baoshun Zhang a, Tingting Chen a, Zhu Chen b, Mingxue Wang a, Dengyu Zheng a, Jinfeng Wu a,
Xiaofei Jiang a, Xuegang Li a,
⇑
a College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, PR China
b Department of Pharmacy, Chongqing Medical and Pharmaceutical College, Chongqing 400030, PR China
a r t i c l e i n f o
a b s t r a c t
A series of hesperidin derivatives were prepared and identified by IR, 1H NMR, and MS spectra. These
compounds were evaluated in vitro and in vivo based on a-glucosidase inhibition, glucose consumption
Article history:
Received 21 July 2012
Revised 13 September 2012
Accepted 17 September 2012
Available online 23 September 2012
of HepG2 cells, and blood glucose level in streptozotocin-induced diabetic mice. The results revealed that
all the compounds exhibited anti-hyperglycemic activities. The inhibition at 10ꢀ3 M of compounds 3 and
7a on a-glucosidase were 55.02% and 53.34%, respectively, as compared to 54.80% by acarbose. Treated
by compound 3 and the reference drug metformin, glucose consumption of HepG2 cell were 1.78 and
2.11 mM, respectively. After the streptozotocin-induced diabetic mice were oral administrated with
compound 3 at 100 mg kgꢀ1 dꢀ1 for 10 days, the blood glucose level of 3 treated mice (13.23 mM,
P <0.05) showed significant difference when compared to model control (23.03 mM). Thus, compound
3 exhibited promising anti-hyperglycemic activity.
Keywords:
Hesperidin derivatives
Anti-hyperglycemic activity
Diabetic mice
a-Glucosidase inhibition
Ó 2012 Elsevier Ltd. All rights reserved.
Diabetes mellitus is a common chronic disease characterized by
Flavonoids, which are based on 2-phenylchromone or 2-phenyl
benzopyrone (Fig. 1), have a C6–C3–C6 carbon skeleton where two
benzene rings (A- and B-ring) are linked through a heterocyclic
pyran or pyrone ring (C-ring) in the middle. The B-ring is located
at the 2-position and the C-ring contains a C2–C3 double bond.
Flavonoids have shown beneficial effects in the treatment of hyper-
glycemic disease probably resulting from changes in the activity of
intracellular enzymes, such as glucosidase enzyme.10 The glucosi-
dase enzymes are located in the brush border of the small intestine
and are required for the breakdown of carbohydrates before mono-
saccharide absorption. Baicalein (5,6,7-trihydroxyflavone) and its
40-hydroxyl substituted derivative (Fig. 1) exhibit promising inhib-
high level of blood glucose, insulin resistance and abnormal insulin
secretion.1 It is associated with the complications such as obesity,
hypertension, and hyperlipidemia leading to cardiovascular risks.2
According to the World Health Organization, the incidence of dia-
betes mellitus was 210 million people worldwide in 2010 and the
number is expected to increase to 330 million by 2025.3 Treatment
of hyperglycemia in diabetes involves diet control, exercise, and
the use of hypoglycemic drugs.4 Caloric restriction and exercise
were adopted by only a small part of patients. Current therapy is
mostly dependent on the hypoglycemic agents. For example,
acarbose,5 an alpha-glucosidase inhibitor, can delay the digestion
and absorption of dietary carbohydrates. Metformin acts by
decreasing hepatic glucose output and increasing peripheral glu-
cose utilization.6 Sulfonylureas lower the blood level by blocking
ATP-dependent potassium channels in pancreatic beta cells to
stimulate insulin secretion.7 Thiazolidinedione acts by activating
peroxisome proliferator-activated receptors (PPARs) that combat
insulin resistance and increase insulin sensitivity.8 Although these
oral therapeutic agents have already been used in clinical situa-
tions, it’s difficult to inhibit their adverse effects, such as hepato-
toxicity, weight gain, and edema.9 Therefore, it’s crucial to search
for new compounds of different chemical classes with better treat-
ment outcomes and less side effects.
itory activity against the
delay the absorption of ingested carbohydrates, reducing the post-
prandial glycemia and insulin peaks. The inhibition on -glucose-
a-glucosidase enzyme and apparently
a
dase by this kind of compounds maybe due to the 6-hydroxyl
group at A-ring and 40-hydroxyl substitution at B-ring.11 Nomura
et al12 assessed the effects of different classes of flavonoids on
insulin-stimulated 2-deoxy-D-[1-3H] glucose uptake by mouse
MC3T3-G2/PA6 cells and found that the key structural features of
flavonoids for inhibition of insulin-stimulated glucose uptake were
OCH3
B
HO
HO
O
O
O
C
rha-glu
O
O
O
OH
A
O
OH
OH
⇑
Corresponding author. Tel.: +86 23 68250728; fax: +86 23 68251046.
E-mail addresses: zbs360@163.com (B. Zhang), xuegangli2000@yahoo.com.cn
2-Phenylchromone
Baicalein
Hesperidin
(X. Li).
Figure 1. Structures of some flavonoids.
0960-894X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2012.09.049

B. Zhang et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7194–7197
7195
the B-ring 40- or 30, 40-OH group, the C-ring C2–C3 double bond of
the flavones, and the A-ring 5-OH of isoflavones. Rawat et al
throughout the useful pH range and provided DHC sweeteners
with improved taste-timing characteristics.
13
evaluated the anti-hyperglycemic activities of various phenolic
C-glycosides on glucose uptake by rat muscle cell lines (L-6) and
low dosed-streptozotocin-induced diabetic rats, the structure–
activity profile revealed that flavonoids with hydroxyl group at po-
sition 3 and 40, and the absence of double bond in C-ring showed an
appreciable increase in activities.
Based on the above findings, many new hesperidin derivatives
and their bioactivities were investigated. However, no previous
studies have been reported on the synthesis and pharmacological
evaluation of hesperetin ethers and esters with anti- hyperglyce-
mic activities. The aim of the present study is to synthesize these
compounds and examine their effects on a-glucosidase inhibition,
Hesperidin is a flavanone glycoside, consisting of an aglycone
and an attached disaccharide (Fig. 1). It is present in a large num-
ber of fruits and vegetables. Until now, no signs of toxicity have
been observed with normal intake. Hesperidin and its derivatives
have been found to possess a wide range of pharmacological prop-
erties, including anti-hyperglycemic,14 antihypercholesterolae-
mic,15 anti-inflammatory16 and antihypertensive17 activities.
Jeong et al15 have synthesized some hesperidin derivatives with
a long alkoxy chain at the 7 position and examined their hypocho-
lesterolemic activities in high cholesterol-fed mice. The 7-O-lauryl
and 7-O-oleyl substitution exhibited strong cholesterol-lowering
effects. DuBois et al18 have prepared sulfonated hesperetin dihydr-
ochalcone (DHC) derivatives that had high water solubility
glucose consumption of HepG2 cells, and blood glucose level in
streptozotocin-induced diabetic mice.
The synthetic pathways adopted for the preparation of novel
hesperidin derivatives are illustrated in Scheme 1. Hydrolysis of
compound 1 and 5 was done in the presence of H2SO4/CH3OH to
give the corresponding 2 and 6. The ether derivatives of the title
compounds were prepared by further reacting with different
substituted aryl and alkyl halides to obtain 3, 7a–c. The ester deriv-
atives 4a–c and 8 were afforded by treatment with acyl halides in
refluxing acetone with triethylamine as base.
All the synthetic compounds were screened in vitro for inhibit-
ing
a-glucosidase activities by a modified method of Chapdelaine
and Rao.19 Acarbose was used as a positive control. The inhibition
OCH
OH
OCH
OCH
3
3
O
O
O
O
O
O
(CH ) SO
3 2
rha-glu
rha-glu
4
3
NaOH
OH
OH
5
1
H SO
H SO
2
4
2
4
MeOH
MeOH
OCH
3
HO
O
1
OR
OH
O
2, 6
(CH CH ) N, Acetone
3
2 3
K CO , Acetone
2
3
O
3
3
2
R
X
R X
OCH
OCH
3
3
O
2
O
O
O
R O
1
1
R
O
OR
OR
OH
O
OH
3, 7a-c
4a-c, 8
X = Cl, Br
Entry
2
3
R1
H
H
H
H
H
CH3
CH3
CH3
CH3
CH3
R2
-
R3
-
-
C6H5CH2
4a
4b
4c
6
7a
7b
7c
8
-
-
-
-
CH3
CH3CH2
C6H5
-
-
-
-
C6H5CH2
CH3(CH2)3
BrCH2(CH2)3
-
CH3CH2
Scheme 1. Synthesis of hesperidin derivatives.

7196
B. Zhang et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7194–7197
Figure 2. Inhibitory effects of compounds (at 10ꢀ3 M) on
a a-glucosidase inhibitory activities (n = 3). Bars with
-glucosidase activities.a-d Values are the means SD of
different letters indicate statistically significant differences among groups at P <0.05.
Figure 3. Influence of compounds (at 10ꢀ4 M) on glucose consumption of HepG2 cells.a-c Values are the means SD of glucose consumption (mM, n = 3). Bars with different
letters indicate statistically significant differences among groups at P <0.05.
Table 1
ꢀ
Effect of compound 3 and metformin on the blood glucose levels (mM) of the streptozotocin-induced diabetic mice at various doses and time intervals (x ꢁ s; n = 6)
Group
Dose/mgꢂkgꢀ1
1 d
3 d
7 d
10 d
Control
Model
Metformin
3
0
0
100
50
6.12 0.68
6.56 0.31
6.40 0.94
7.02 0.57
19.93 6.36
16.98 6.87
17.50 5.30
16.78 6.24
23.97 3.79
20.72 8.23
21.25 4.78
20.12 8.74
23.60 4.25
14.47 3.23*
19.35 4.80
19.18 7.38
23.03 3.94
10.00 3.09**
20.10 9.59
13.23 3.88*
100
*
P <0.05 vs model group.
P <0.01 vs model group.
**
against
a
-glucosidase was calculated following the formula of the
compared to acarbose (54.8%) at the concentration of 10ꢀ3 M. They
had the highest inhibition among the ten compounds. The reason
was most likely that the introduction of a benzyl group at the hy-
droxyl oxygen in C-7 position could increase the selectivity of the
biotransformation. The benzyl group may act as an excellent affin-
ity group, leading to the enhancement of selective interaction of
the substrate with the active site of the enzyme.21
These compounds were tested for their effects on glucose
consumption in HepG2 cell by the method of He.22 Metformin
was taken as the reference drug. The data are depicted in Figure
3. Treated by compound 3 and metformin at 10ꢀ4 M, glucose con-
sumption of HepG2 cell were 1.78 and 2.11 mM, respectively.
Compound 3 had the highest glucose consumption among these
inhibitory ratio. The results are shown in Figure 2.
Comparing the inhibitory ratio of compounds 2–6, as well as
compounds 4b–8, it indicated that when the B ring 30-OH was re-
placed by methoxy group, the inhibition on a-glucosidase became
lower; when the hydroxyl group at C-7 position in A ring was
substituted by short alkyl ether or ester, the inhibitory activities
were also lower. These results are in good agreement with the pre-
vious report by Nomura.12 7b and 7c showed no difference in
inhibiting
the inductive effect of bromo atom decreases as its distance
increasing from the oxygen atom at C-7 position.20 The
-glucosi-
dase inhibition of 3 and 7a were 55.0% and 53.3%, respectively, as
a-glucosidase activity, this may result from the fact that
a

B. Zhang et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7194–7197
7197
synthetic compounds. However, 7a was less effective than 3, which
References and notes
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All the compounds 2–8 were evaluated for their in vivo anti-
hyperglycemic activity on blood glucose level in streptozotocin-in-
duced diabetic mice.23 Metformin was also chosen as the positive
control. The results are shown in Table 1.
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The results indicated that compound 3 has apparent effects on
blood glucose levels in streptozotocin-induced diabetic mice just
as the metformin. After respectively, oral administration of com-
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3 exhibited promising anti-hyperglycemic
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We would like to thank Professor Erkang Fan and Dr. Zhongshen
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technical assistance; we also thank the Fundamental Research
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Scientific Research Foundation for Ph. D of Southwest University
of China (SWU111072, 111064) and Medical & Scientific Research
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Supplementary data
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Supplementary data (General procedures and spectral data)
associated with this article can be found, in the online version, at
http://dx.doi.org/10.1016/j.bmcl.2012.09.049.