Synthesis, anti-hyperglycaemic activity, and in-silico studies of N-substituted 5-(furan-2-ylmethylene)thiazolidine-2,4-dione derivatives

Article abstract of DOI:10.1007/s11164-016-2592-x

Thiazolidinedione derivatives have been used as anti-hyperglycemic agents in diabetic patients since last decade. In the present study, a series of N-substituted-5-(furan-2-ylmethylene)thiazolidine-2,4-dione derivatives were synthesized and characterized by ¹H-NMR, ¹³C-NMR and mass spectra. The introduction of the alkyl/haloalkyl moiety onto the amidic nitrogen of the thiazolidine-2,4-dione ring was intended to enhance the anti-hyperglycaemic activity, which was further tested in vivo by using alloxan-induced diabetic laca mice. Molecular docking simulation studies further helped in understanding the nature of the interactions and the binding mode of ligands inside the active site of the protein tyrosine phosphatase 1B enzyme, which negatively regulates the insulin signaling pathway. The compounds were screened for in-vivo anti-hyperglycaemic activity in which compounds 9 and 10 have exhibited significant decreases in blood glucose level comparable to that of pioglitazone.

Full text of DOI:10.1007/s11164-016-2592-x

Res Chem Intermed
DOI 10.1007/s11164-016-2592-x
Synthesis, anti-hyperglycaemic activity, and in-silico
studies of N-substituted 5-(furan-2-ylmethylene)
thiazolidine-2,4-dione derivatives
Manoj Kumar Mahapatra1 Rajnish Saini1
•
•
Manoj Kumar1
Received: 11 March 2016 / Accepted: 23 May 2016
Ó Springer Science+Business Media Dordrecht 2016
Abstract Thiazolidinedione derivatives have been used as anti-hyperglycemic
agents in diabetic patients since last decade. In the present study, a series of N-
substituted-5-(furan-2-ylmethylene)thiazolidine-2,4-dione derivatives were synthe-
sized and characterized by 1H-NMR, 13C-NMR and mass spectra. The introduction
of the alkyl/haloalkyl moiety onto the amidic nitrogen of the thiazolidine-2,4-dione
ring was intended to enhance the anti-hyperglycaemic activity, which was further
tested in vivo by using alloxan-induced diabetic laca mice. Molecular docking
simulation studies further helped in understanding the nature of the interactions and
the binding mode of ligands inside the active site of the protein tyrosine phosphatase
1B enzyme, which negatively regulates the insulin signaling pathway. The com-
pounds were screened for in-vivo anti-hyperglycaemic activity in which compounds
9 and 10 have exhibited significant decreases in blood glucose level comparable to
that of pioglitazone.
Keywords Diabetes Á N-substituted thiazolidine-2,4-dione Á Anti-hyperglycaemic
activity Á Docking
Introduction
Diabetes mellitus has emerged as a major health care problem worldwide due to
sedentary lifestyle, abrupt changes in human environment, culture, and rapid
urbanization. Diabetes mellitus is a complex metabolic syndrome characterized by
hyperglycemia and its severity often leads to poor wound healing, nephropathy,
blurred vision, neuropathy, cardiovascular diseases, and premature death [1].
Diabetes Atlas 2015, a recent study by the International Diabetes Federation (IDF),
&
Manoj Kumar
manoj_uips@pu.ac.in
1
University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014, India
123

M. K. Mahapatra et al.
has estimated the global occurrence of diabetes to be 415 million cases with another
318 million individuals suffering from impaired glucose tolerance, placing them at
high risk of developing diabetes in the near future [2]. Diabetes is quickly gaining
the status of a potential epidemic in the world, as its prevalence is predicted to
double globally from 171 million in 2000 to 366 million in 2030, with a maximum
increase in India [3, 4].
Glitazones, having a common structural framework with 2,4-thiazolidinediones
(TZD), were approved as anti-hyperglycemic drugs in the last decade. This TZD
moiety having sulphur atom in a five-membered ring has shown anti-hypergly-
caemic activity and has also been reported as an insulin sensitizer, peroxisome
proliferator-activator receptor c (PPARc) agonist, PTP1B inhibitor, and aldose
reductase inhibitor. Thus, TZDs decrease the blood glucose concentration by
ameliorating insulin resistance, promote glucose utilization in peripheral tissue, and
thereby normalize elevated blood glucose levels [5]. Following the initial report of a
novel antidiabetic agent called ciglitazone (benzylthiazolidinedione) from Takeda
laboratories, TZD analogues have emerged as a new class of antidiabetic agents.
Various substituted TZD analogues such as troglitazone, englitazone, rosiglitazone,
and pioglitazone have been developed and used clinically for the treatment of type 2
diabetes (Fig. 1). However, except for pioglitazone, all others were withdrawn from
clinical use due to serious side effects [6]. The side effects associated with TZD
derivatives may have emerged due to the acidic amidic proton of the TZD nucleus,
which imitates the carboxylate anion of the natural fatty acid ligands, enabling its
binding to the peroxisome proliferator-activator receptor (PPAR) belonging to the
steroid/thyroid/retinoid receptor super family of ligand-activated transcription
factors. Hence, N-substituted TZD derivatives were expected to have lesser side
effects as compared to the current glitazones [7, 8]. Bhattarai et al. [9, 10] have
Fig. 1 Reported anti-hyperglycaemic agents having a TZD scaffold
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Synthesis, anti-hyperglycaemic activity, and in-silico…
reported significant PTP1B inhibitory and anti-hyperglycaemic activity of various
TZD derivatives. Lakshminarayana et al. [11] have reported various furan
carboxylic acids as potential antidiabetic agents. Therefore, it was envisaged to
design a series of small molecule inhibitors by connecting both the furan and TZD
nucleus by a vinylic linkage, and the amidic nitrogen of TZD was substituted by
alkyl/haloalkyl groups. In the present investigation synthesis, characterization and
in-vivo anti-hyperglycaemic activity of N-substituted 5-(furan-2-ylmethylene)thia-
zolidine-2,4-dione derivatives are herein reported. Docking studies were also
carried out for supplementing the in-vivo results.
Experimental
Chemistry
All reagents were obtained commercially and were of the highest quality and used
without further purification. Solvents were freshly distilled and used. Melting points
1
were recorded on a Veego-540 melting-point apparatus and were uncorrected. H-
NMR and 13C-NMR were recorded on a Bruker AC-400F, 400 MHz spectrometer
for solutions in deuteriochloroform (CDCl3), deuterated dimethylsulfoxide (DMSO-
d6), and were reported in parts per million (ppm), downfield from tetramethylsilane
(TMS) as an internal standard. Splitting patterns were designated as singlet (s),
doublet (d), triplet (t), or multiplet (m). Chemical shift values are presented in parts
per million (ppm). Mass spectroscopy (MS) was conducted using a Micromass LCT
system. All reactions were monitored by TLC (silica gel-coated aluminum sheets).
The N-substituted derivatives of thiazolidinedione have been synthesized as
outlined in (Scheme 1).
Scheme 1 Synthesis of N-substituted 5-(furan-2-ylmethylene)thiazolidine-2,4-diones
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M. K. Mahapatra et al.
Synthesis of thiazolidine-2,4-dione (1)
A mixture of chloroacetic acid (56.7 g, 0.6 mol) and thiourea (45.6 g, 0.6 mol) was
dissolved in water (125.0 ml) and stirred for 15 min. Hydrochloric acid (conc.,
60.0 ml) was added dropwise to this solution. The reaction mixture was refluxed for
12 h and then cooled in an ice bath. The product separated as white needles, was
filtered, washed repeatedly with water to remove traces of hydrochloric acid, dried,
and then recrystallised from methanol to yield 2,4-thiazolidinedione [12].
White solid (Yield: 62.58 g, 88.2 %; m. p. 123–125 °C); Rf: 0.49 (Chloroform :
1
Methanol :: 10 : 1); IR (KBr): 3132, 1739, 1662, 615 cm-1; H NMR (DMSO-d6,
ppm): d 11.98 (s, 1H, NH), d 4.09 ppm (s, 2H, CH2); 13C NMR (DMSO-d6, ppm): d
173.54 (CO), d 172.79 (CO), d 35.65 (Aromatic C).
Synthesis of (Z)-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (2)
A mixture of thiazolidine-2,4-dione (2.92 g, 25 mmol) and anhydrous sodium
acetate (2.05 g, 25 mmol) in glacial acetic acid was refluxed at 110–120 °C for
20 min. Furfuraldehyde (2.07 ml, 25 mmol) was added into the mixture and
refluxed for 36 h using a Dean–Stark apparatus to remove water from the reaction.
The solvent was evaporated and the residue was added into crushed ice with stirring.
The separated product was filtered, washed with water, and dried. It was crystallised
from acetone to yield (Z)-5-(furan-2-ylmethylene)thiazolidine-2,4-dione.
Dark brown solid (Yield: 1 g, 20.5 %); m. p.: 230–232 °C); Rf: 0.57 (hexane :
ethylacetate :: 2:1); IR (KBr): 3143, 3030, 1725,1684 cm-1; 1H NMR (DMSO-d6):
d 6.6 (q, 1H, Ar–H), 7.01 (d, 1H, Ar–H), 7.58 (s, 1H, =CH), 7.95 (d, 1H, Ar–H) and
12.39 (br s, 1H, NH) ppm; 13C NMR (DMSO-d6): d 113.21 (Aromatic-C), 118.09
(Aromatic-C), 118.32 ([C=, TZD), 120.46 (=CH), 146.99 (Aromatic-C), 149.22
(Aromatic-C), 166.93 (CO, TZD) and 168.46 (CO, TZD) ppm.
General procedure for synthesis of compounds 3–10
A mixture of (Z)-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (1.36 g, 7 mmol)
and anh. potassium carbonate (2 g, 14 mmol) in acetone was refluxed for 20 min.
Suitable alkyl/haloalkyl derivatives (10.5 mmol) were added to the mixture and
refluxed for 24 h. The solvent was evaporated under reduced pressure to obtain a
solid residue. The solid residue was mixed with crushed ice with stirring for 30 min.
The product obtained was filtered, washed with water to remove traces of inorganic
salt, and dried. It was recrystallized from acetone to afford the final compounds.
(Z)-3-ethyl-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (3)
Light brown solid (Yield: 0.750 g, 48 %; m. p.: 119–121 °C); Rf: 0.62 (hex-
1
ane:ethylacetate 2:1); IR (KBr): 3039, 2981, 1730, 1668, 1614, 1436 cm-1; H
NMR (CDCl3): d 1.25 (t, 3H, CH3), 3.79 (q, 2H, CH2 –N\), 6.5 (q, 1H, Ar–H), 6.78
(d, 1H, Ar–H), 7.63 (s, 1H, =CH) and 7.67 (d, 1H, Ar–H) ppm; 13C NMR (CDCl3):
d 13.15 (CH3), 36.91 (CH2–N\), 113.13 (Aromatic-C), 117.63 (-Aromatic-C),
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Synthesis, anti-hyperglycaemic activity, and in-silico…
119.41 ([C=, TZD), 119.45 (=CH), 146.37 (Aromatic-C), 149.8 (Aromatic-C),
166.03 (CO, TZD) and 168.65 (CO, TZD) ppm; Mass (EI): m/z 223.04 [M]?
(Z)-3-(3-chloropropyl)-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (4)
Light brown solid (Yield: 0.7 g, 37 %; m. p.: 116–118 °C); Rf: 0.59 (hexane:ethy-
lacetate 2:1); IR (KBr): 3034, 2954, 1730, 1671, 1614, 1439 cm-1 1H NMR
;
(CDCl3): d 2.15 (quint, 2H, CH2), 3.56 (t, 2H, CH2–Cl), 3.89 (t, 2H, CH2–N\), 6.58
(q, 1H, Ar–H), 6.8 (d, 1H, Ar–H), 7.64 (s, 1H, =CH) and 7.67 (d, 1H, Ar–H) ppm;
13C NMR (CDCl3): d 30.69 (CH2), 39.48 (CH2–Cl), 41.85 (CH2–N\), 113.21
(Aromatic-C), 117.97 (Aromatic-C), 118.49 ([C=, TZD), 119.86 (=CH), 146.54
(=CH–O–), 149.73 (Aromatic-C), 166.08 (CO, TZD) and 168.78 (CO, TZD) ppm;
Mass (EI) : m/z 271 [M]?, 273.02[M?2]?.
(Z)-3-(2-bromoethyl)-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (5)
Brown solid (Yield: 0.64 g, 30 %; m. p.: 120–122 °C); Rf: 0.55 (hexane:ethylac-
etate 2:1); IR (KBr): 3042, 2959, 1736, 1672, 1613, 1429 cm-1; 1H NMR (CDCl3):
d 3.51 (t, 2H, CH2–Br), 4.07 (t, 2H, CH2–N\), 6.52 (q, 1H, Ar–H), 6.74 (d, 1H, Ar–
H), 7.56 (s, 1H, =CH) and 7.61 (d, 1H, Ar–H) ppm; 13C NMR (CDCl3): d 26.93
(CH2–Br), 42.52 (CH2–N\), 113.27, 118.21 (Aromatic-C), 118.56 ([C=, TZD),
120.22 (=CH), 146.68, 149.67 (Aromatic-C), 165.72 (CO, TZD) and 168.56 (CO,
TZD) ppm; Mass (ESI) : m/z 302.78 [M]?, 304.78[M?2]?.
(Z)-5-(furan-2-ylmethylene)-3-propylthiazolidine-2,4-dione (6)
Brown solid (Yield: 0.80 g, 51 %; m. p.: 110–112 °C); Rf: 0.49 (hexane :
ethylacetate :: 2:1); IR (KBr): 3038, 2955, 1727, 1674, 1610, 1432 cm-1 1H
;
NMR (CDCl3): d 0.87 (t, 3H, CH3), 1.60 (m, 2H, CH2), 3.62 (t, 2H, CH2–N\),
6.49 (q, 1H, Ar–H), 6.70 (d, 1H, Ar–H), 7.56 (s, 1H, =CH) and 7.59 (d, 1H, Ar–H)
ppm; 13C NMR (CDCl3): d 11.17 (CH3), 21.16 (CH2), 43.39 (CH2–N\), 113.11,
117.59 (Aromatic-C), 119.37 ([C=, TZD), 119.46 (=CH), 146.35, 149.85
(Aromatic-C), 166.27 (CO, TZD) and 168.83 (CO, TZD) ppm; Mass (EI): m/z
238.56[M?1]?.
(Z)-3-butyl-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (7)
Light yellow solid (Yield: 1.50 g, 85 %; m. p.: 95–97 °C); Rf: 0.64 (hexane :
1
ethylacetate :: 2:1); IR (KBr): 3042, 2958, 1734,1667,1615,1430 cm-1; H NMR
(CDCl3): d 0.95 (t, 3H, CH3), 1.35 (m, 2H, CH2), 1.63 (quint, 2H, CH2), 3.72 (t, 2H,
CH2–N\), 6.56 (q, 1H, Ar–H), 6.77 (d, 1H, Ar–H), 7.63 (s, 1H, =CH) and 7.66
(d,1H, Ar–H) ppm; 13C NMR (CDCl3): d 13.61 (CH3), 19.97 (CH2), 29.83 (CH2),
41.67 (CH2–N\), 113.11, 117.57 (Aromatic-C), 119.38 ([C=, TZD), 119.42 (=CH),
146.34, 149.84 (Aromatic-C), 166.22 (CO, TZD) and 168.76 (CO, TZD) ppm; Mass
(ESI): m/z 251.53 [M]?.
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M. K. Mahapatra et al.
(Z)-5-(furan-2-ylmethylene)-3-methylthiazolidine-2,4-dione (8)
Brown solid (Yield: 0.96 g, 65.6 %; m. p.: 129–131 °C); Rf: 0.60 (hexane :
1
ethylacetate :: 2:1); IR (KBr): 3043, 2956, 1729, 1671, 1614,1421 cm-1; H NMR
(CDCl3): d 3.22 (s, 3H, CH3), 6.57 (q, 1H, Ar–H), 6.78 (d, 1H, Ar–H), 7.64 (s, 1H,
=CH–),7.67 (d, 1H, Ar–H) ppm; 13C NMR (CDCl3): d 27.78 (CH3), 113.15, 117.80
(Aromatic-C), 119.19 ([C=, TZD), 119.59 (=CH), 146.44, 149.73 (Aromatic-C),
166.28 (CO, TZD), 168.88 (CO, TZD) ppm; Mass (ESI): m/z 210.46 [M?1]?.
(Z)-3-(2-chloroethyl)-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (9)
Brown solid (Yield: 0.70 g, 38 %; m. p.: 87–89 °C); Rf: 0.57 (hexane : ethylacetate
:: 2:1); IR (KBr): 3039, 1737, 1677, 1617, 1424 cm-1; 1H NMR (CDCl3): d 3.75 (t,
2H, CH2–Cl), 4.08 (t, 2H, CH2–N\), 6.58 (q, 1H, –Ar–H), 6.81 (d, 1H, Ar–H), 7.66
(s, 1H, =CH–),7.68 (d, 1H, Ar–H) ppm; 13C NMR (CDCl3): d 39.87 (CH2–Cl),
42.66 (CH2–N\), 113.27, 118.22 (Aromatic-C), 118.55 ([C=, TZD), 120.19 (=CH),
146.68, 149.66 (Aromatic-C), 165.84 (CO, TZD), 168.68 (CO, TZD) ppm; Mass
(EI): m/z 257.73 [M]?, 258.67 [M?1]1.
(Z)-5-(furan-2-ylmethylene)-3-pentylthiazolidine-2,4-dione (10)
Light brown solid (Yield: 0.99 g, 54 %; m.p.: 62–64 °C); Rf: 0.56 (hexane:ethy-
1
lacetate 2:1); IR (KBr): 3042, 2929, 1735, 1669, 1430 cm-1; H NMR (CDCl3): d
0.89 (t, 3H, CH3), 1.32 (m, 4H, CH2–CH2), 1.65 (quint, 2H, CH2), 3.72 (t, 2H, CH2–
N\), 6.57 (q, 1H, Ar–H), 6.77 (d, 1H, Ar–H), 7.63 (s, 1H, =CH), 7.66 (d, 1H, Ar–H)
ppm; 13C NMR (CDCl3): d 13.92 (CH3), 22.24 (CH2), 27.48 (CH2), 28.81 (CH2),
41.90 (CH2–N\), 113.12, 117.61 (Aromatic-C), 119.37 ([C=, TZD), 120.19 (=CH),
146.36, 149.84 (Aromatic-C), 165.24 (CO, TZD), 168.80 (CO, TZD) ppm; Mass
(EI): m/z 265.12 [M]?.
In-vivo anti-hyperglycaemic activity
Albino mice (Laca strain) of either sex, bred in the Central Animal House Facility of
Panjab University, were used in the present antidiabetic screening. Animals were
housed in polypropylene cages. They were housed (six mice per cage) under
standard (25 2 °C, 60–70 % humidity) laboratory conditions, maintained on a
12-h natural day-night cycle, with free access to standard food and water. Animals
were acclimatized to laboratory conditions for 1 week before the experiment. The
experimental protocol was approved by the Institutional Animal Ethics Committee
(PU/IAEC/S/14/105) and conducted according to the CPCSEA guidelines.
Diabetes was induced in overnight-fasted mice by a single i.p. injection of
Alloxan (150 mg/kg) dissolved in normal physiological saline. Animals were fed
with 5 % glucose solution for the first 12 h to prevent hypoglycemia. A blood
glucose monitoring system (eBsensor blood glucose meter, Visgeneer Inc. Taiwan)
was used for measurement of blood glucose concentration. The elevated blood
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Synthesis, anti-hyperglycaemic activity, and in-silico…
glucose levels determined at 72 h confirmed hyperglycemia. Animals with blood
glucose concentrations greater than 250 mg/dl were selected for the study [11, 13].
Acute study
In the acute study, animals were fasted overnight and the fasting blood glucose level
at 0 h was calculated. All the test compounds (homogenized suspension in 0.5 %
CMC and a permissible amount of Tween 80) and the standard drug pioglitazone
were administered orally at a fixed dose of 30 mg/kg body weight. Animals of the
vehicle-treated group were given an equal amount of 0.5 % CMC and those of the
control group were kept as such. Using the tail prick method, the blood glucose level
was monitored at 2, 4, 6, and 24 h after administration of test compounds. The %
reduction in blood glucose level was calculated with respect to the control group. A
10 % reduction in serum glucose level versus control group levels was considered
as a positive screening result.
Subacute study
In the subacute study, the test compounds (homogenized suspension in 0.5 %
CMC and a permissible amount of Tween 80) and the standard drug pioglitazone
were administered once daily by oral gavage at a fixed dose of 30 mg/kg body
weight for 7 days at a fixed time. After 7 days, blood samples were taken from
animals and percentage change in blood sugar level was determined. The data
obtained were analyzed by one-way analysis of variance (ANOVA) followed by
Dunnett’s test. The results were expressed as mean standard error of mean
(SEM) for each group. Statistical significance of differences between groups was
determined by one-way ANOVA followed by Dunnett’s test. A probability
(P) value of less than 0.05 indicated statistically significant difference between the
treatment groups.
Molecular docking study
Protein tyrosine phosphatase 1B enzyme has emerged as a therapeutic target for the
management of type 2 diabetes, as it negatively regulated the insulin signaling
pathway. A number of TZD derivatives have been reported as PTP1B inhibitors that
control hyperglycemia [7, 9, 10]. Therefore, a 3D structure of the PTP1B enzyme
was used as the receptor for the docking studies. The crystal structure of protein
tyrosine phosphatase 1B (PDB ID: 2NT7) was downloaded from the protein data
bank. Another 3D structure of the enzyme peroxisome proliferator-activated
receptor gamma (PPARc) was also downloaded from the PDB (2XKW) for carrying
out additional docking studies with this receptor. Using a protein preparation
wizard, bond orders were assigned, hydrogens were added, bonds to metals were
deleted, the formal charges on the metal and the neighboring atoms were adjusted,
˚
and finally, waters that were more than 5 A in distance were deleted. The receptor
structure was refined by using restrained minimization. The receptor grid was set up
and the co-crystallized ligand was excluded for defining the receptor structure. The
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M. K. Mahapatra et al.
grids were defined by keeping the co-crystallized ligand as a center and using the
default box size. The XP (extra precision) docking mode of Glide 5.8 (Schrodinger
LLC., New York) was utilized for the molecular docking of low-energy conformers
into the binding pocket of PTP1B [14–16]. Receptor structure was kept rigid,
whereas the ligands were kept flexible during the docking. The final evaluation was
done with a glide docking score, and a single best pose was generated for each
ligand.
Ligand-receptor binding energy study
The binding free energy of the ligand-receptor complex was determined by using
the MM/GBSA (molecular mechanics/generalized born model and solvent acces-
sibility) module of Prime 3.1 (Schrodinger LLC., New York) [17–19].
DGbind ¼ Gcomplex À Greceptor À Gligand
DGbind = Ligand-receptor binding free energy change; Gcomplex = Free energy of
ligand-receptor complex; Greceptor = Free energy of receptor; Gligand = Free energy
of ligand.
ADME prediction study
Qikprop 3.5 (Schrodinger LLC., New York) module was utilized for the prediction
of physico-chemical descriptors and pharmacokinetically important properties of
the synthesized compounds [20].
Results and discussion
The designed compounds were synthesized by using known synthetic approaches.
Thiazolidine-2,4-dione (1) was synthesized by condensing chloroacetic acid and
thiourea in the presence of conc. HCl. Knoevenagel condensation of thiazolidine-
2,4-dione and furan-2-carboxaldehyde was carried out to afford (Z)-5-(furan-2-
ylmethylene)thiazolidine-2,4-dione (2). Compound 2 was subjected to N-alkylation
under basic conditions to give the final compounds (3–10). The synthesized
compounds were characterized by 1H-NMR, 13C-NMR, and mass spectroscopy. The
exocyclic double bond was Z-configuration in all the synthesized compounds, which
were also supported by the NMR data [21, 22]. The vinylic proton appeared within
1
7.56–7.64 ppm in H-NMR, which confirmed the synthesis of Z-isomers. Disap-
1
pearance of the NH peak in H-NMR and appearance of aliphatic alkyl protons
confirmed the synthesis of the final compounds.
In-vivo anti-hyperglycemic activity of the synthesized compounds was carried
out using an alloxan-induced diabetic mice model taking pioglitazone as a positive
control. The % reduction in blood sugar level of the test compound-treated groups
showed similar profile types (Table 1) as that of pioglitazone. The blood sugar level
was decreased from 2 up to 4 h and then again gradually increased up to 24 h. The
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Synthesis, anti-hyperglycaemic activity, and in-silico…
Table 1 In-vivo anti-hyperglycaemic activity of synthesized compounds
Compounds Effect of compound 3–10 (30 mg/kg) on alloxan-induced diabetic mice
2 h
4 h
6 h
24 h
7th day
Control
1.16 0.70
1.35 0.47
2.31 0.42
6.76 1.52
8.02 0.70
Pioglitazone -36.02 0.87 -44.78 1.66 -40.27 1.49 -34.93 0.79 -34.87 2.15
3
-17.21 1.66 -25.75 1.63 -20.40 2.23 -11.55 0.88 -12.48 1.69
-31.83 1.82 -36.38 2.08 -33.12 1.25 -29.58 1.04 -28.82 1.54
4
5
-14.61 0.98 -23.79 1.15 -16.67 1.49
-8.24 2.00
-9.89 1.50
-8.93 1.53
6
-11.9 1.46 -17.73 1.47 -14.74 1.83 -10.80 2.07
7
-21.88 1.49 -28.30 1.73 -27.21 1.30 -20.21 1.47 -17.62 1.88
-12.13 1.14 -18.54 1.53 -19.86 1.60 -9.10 2.27 -9.95 1.41
8
9
-35.51 1.47 -43.72 2.08 -39.43 0.94 -30.06 1.35 -34.92 1.15
-37.89 1.13 -43.11 1.56 -39.39 1.74 -31.83 1.62 -32.97 1.52
10
most pronounced effect was obtained after 4 h of treatment with the test
compounds. After 7 days of treatment, the % reduction in blood sugar level ranged
from 8.93 to 34.97 as compared to 34.87 for pioglitazone. Compounds 9 and 10
were observed to lower the blood sugar level by 32.85 and 34.97 %, respectively,
and are comparable to the in-vivo activity of standard drug pioglitazone. The in-
vivo data was depicted in (Fig. 2). At 4 h, the decrease in sugar level was the same
for compound 10 and pioglitazone. A probability (P) value of less than 0.05
indicated a statistically significant difference between the treatment groups.
The probable binding conformation of the active compounds (9 and 10) in the
binding pocket of PTP1B was studied by docking. A common binding orientation of
all the ligands was observed inside the PTP1B active site. Both compounds 9 and 10
have shown H-bonding interaction with the catalytic active site residue Gly220. The
top-ranked binding pose of the active compounds and docking interactions of
20
10
Control
Pioglitazone
3
0
4
2 hr
4 hr
6 hr
24 hr
7th day
-10
-20
-30
-40
-50
5
6
7
8
9
10
Fig. 2 Graphical representation of in-vivo anti-hyperglycemic activity of synthesized compounds
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M. K. Mahapatra et al.
Fig. 3 Binding pose of compound 9 and docking interactions inside the binding pocket residues of
PTP1B
Fig. 4 Binding pose of compound 10 and docking interactions inside the binding pocket residues of
PTP1B
compound 9 and 10 were depicted in (Figs. 3, 4), respectively. The amidic nitrogen
of the TZD ring was found away from the catalytic residues site (His214–Arg221),
and the N-alkyl region did not show any H–bonding network with binding site
residues. This may be due to the substitution of amidic nitrogen with lipophilic alkyl
groups.
These compounds have been additionally docked with PPAR gamma (2XKW),
the X-ray structure of which was available in the protein data bank. The docking
scores ranged from -5.7 to -5.0 (PPARc) as compared to -3.8 to -2.7 (PTP1B),
suggesting that the synthesized compounds more favorably interacted with PPAR
gamma than with PTP1B.
The docking results were quantified in terms of DG binding energy, DG bind
coulomb, DG bind H-bond, DG bind Lipo, and DG bind VdW. The DG binding
energy of the ligand-receptor complex showed good correlation with their docking
score and measured the ligand-receptor affinity. For the present compounds, binding
energy ranged from -60.426 to -43.16 kcal/mol. The binding free energy of the
ligand-receptor complex was determined by MM/GBSA method and was presented
in Table 2.
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M. K. Mahapatra et al.
Table 3 Predicted ADME parameters
Compound QPlogPw QPlogPo/ QPlogS QPPCaco QPlogBB % Human
Rule
of
Rule
of
w
oral
absorption
five
three
3
5.27
1.969
2.803
2.536
2.27
-2.147 1403.647 -0.289
-3.434 1408.958 -0.219
-2.945 1404.322 -0.183
-2.644 1408.219 -0.377
-3.107 1408.827 -0.466
-2.062 1052.907 -0.32
-2.974 1405.442 -0.132
-3.571 1408.842 -0.554
94.803
100
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
5.216
5.153
5.13
5
100
6
96.593
100
7
4.989
5.516
5.358
4.848
2.666
1.549
2.449
3.061
8
90.11
100
9
10
100
The ADME prediction study helps in generating drug-like candidates that are less
likely to be rejected during clinical trials. A number of physico-chemical and
pharmacokinetic descriptors (QPlogPw, QPlogPo/w, QPlogS, QPPCaco, QPlogBB,
% Human oral absorption, rule of five, and rule of three) were predicted. The
ADME parameters were within the acceptable range defined for human use,
exhibiting their druggable nature, and were presented in Table 3.
Conclusion
A series of N-substituted 5-(furan-2-ylmethylene)thiazolidine-2,4-dione derivatives
were synthesized and tested in vivo for anti-hyperglycaemic activity. Introduction
of chloroethyl and pentyl group on amidic nitrogen of TZD produced (Z)-3-(2-
chloroethyl)-5-(furan-2-ylmethylene)thiazolidine-2,4-dione (9) and (Z)-5-(furan-2-
ylmethylene)-3-pentylthiazolidine-2,4-dione (10), respectively, which were found
to be significantly potent like pioglitazone. Additional docking studies were also
carried out to predict the binding nature of these compounds inside the binding
pocket of the PTP1B enzyme. These preliminary results would be helpful in
designing and optimizing a more potent TZD scaffold containing anti-hyper-
glycemic agents.
Acknowledgments The authors gratefully acknowledge UGC (University Grant Commission), New
Delhi, India, for providing a UGC-RFSMS fellowship to Manoj Kumar Mahapatra. The authors thank Mr.
Avtar Singh (SAIF, Panjab University, Chandigarh, India) for doing the NMR study/characterization. The
authors report no conflicts of interest.
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