Novel thiazolidinedione-5-acetic-acid-peptide hybrid derivatives as potent antidiabetic and cardioprotective agents

Article abstract of DOI:10.1016/j.biopha.2017.01.160

Thiazolidinediones (TZDs) are one of the important clinically established antidiabetic agents. Amino-acid and peptides have an advantage of better target selectivity and specificity. As hybrids, they also improved absorption and showed better bioavailability, which in turn makes them safer. Hence, here an effort has been made to synthesize hybrids of thiazolidinedione with amino-acids and peptides and evaluate their antidiabetic and cardioprotective effect in streptozotocin-nicotinamide (STZ-NA) induced Type 2 diabetes mellitus (T2DM) rat models. A series of 14 thiazolidinedione-5-acetic acid hybrids with of different amino-acids and peptide combinations were synthesized, characterized and further screened for antidiabetic and cardioprotective activity. Among all, six compounds T1 (SSDMA1), T4 (SSDMA4), T5 (SSDMA5), T7 (SDMA13), T9 (SSDMA15) and T13 (SSDMA49) showed better antioxidant activity and comparable % glucose uptake by yeast cells. Hence, the in vivo antidiabetic screening was done for these six compounds. Among all six T1, T7, T13 showed significant blood glucose level decrease compared to standard pioglitazone HCl. Also T1, T7 and T13 showed better antioxidant activity with lower IC₅₀ value than standard ascorbic acid, and hence in vivo cardioprotective studies were done for these. The ECG studies showed that T1 (SSDMA1) and T7 (SSDMA13) were better effective than SDMA49 (T13) in restoring the normal functioning of the heart, thus may help in preventing the development of diabetic cardiomyopathy (DCM) and controlling T2DM.

Full text of DOI:10.1016/j.biopha.2017.01.160

Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
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Original article
Novel thiazolidinedione-5-acetic-acid-peptide hybrid derivatives as
potent antidiabetic and cardioprotective agents
*
D. Maji , S. Samanta
Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi 835215, Jharkhand, India
A R T I C L E I N F O
A B S T R A C T
Article history:
Thiazolidinediones (TZDs) are one of the important clinically established antidiabetic agents. Amino-
acid and peptides have an advantage of better target selectivity and specificity. As hybrids, they also
improved absorption and showed better bioavailability, which in turn makes them safer. Hence, here an
effort has been made to synthesize hybrids of thiazolidinedione with amino-acids and peptides and
evaluate their antidiabetic and cardioprotective effect in streptozotocin-nicotinamide (STZ-NA) induced
Type 2 diabetes mellitus (T2DM) rat models.
Received 6 November 2016
Received in revised form 26 January 2017
Accepted 28 January 2017
Keywords:
Thiazolidinediones
Hybrids
A series of 14 thiazolidinedione-5-acetic acid hybrids with of different amino-acids and peptide
combinations were synthesized, characterized and further screened for antidiabetic and cardioprotec-
tive activity.
Peptides
Antidiabetic
Among all, six compounds T1 (SSDMA1), T4 (SSDMA4), T5 (SSDMA5), T7 (SDMA13), T9 (SSDMA15)
and T13 (SSDMA49) showed better antioxidant activity and comparable % glucose uptake by yeast cells.
Hence, the in vivo antidiabetic screening was done for these six compounds. Among all six T1, T7, T13
showed significant blood glucose level decrease compared to standard pioglitazone HCl. Also T1, T7 and
T13 showed better antioxidant activity with lower IC50 value than standard ascorbic acid, and hence in
vivo cardioprotective studies were done for these. The ECG studies showed that T1 (SSDMA1) and T7
(SSDMA13) were better effective than SDMA49 (T13) in restoring the normal functioning of the heart,
thus may help in preventing the development of diabetic cardiomyopathy (DCM) and controlling T2DM.
Cardioprotective
Diabetic-cardiomyopathy
C
ꢀ 2017 Elsevier Masson SAS. All rights reserved.
to diabetic cardiomyopathy [1]. Thiazolidinediones are the most
extensively used oral hypoglycemic agent besides sulfonylureas
1. Introduction
[2], which control the increasing blood glucose level by binding
and activating PPAR
Fast growing industrialization and sedentary lifestyles have
raised the incidences of Type 2 diabetes mellitus (T2DM), which is
engulfing the whole world like an epidemic. T2DM is a chronic
metabolic disorder, accompanied with numerous complications
which make the management of T2DM a big challenge to the
medical field. Prolonged and uncontrolled T2DM accelerates the
development of many micro and macrovascular complications
which affect major vital organs of the body, the heart being one of
them. It causes cellular level changes in the myocardium of the
diabetic patients resulting in various structural changes, giving rise
g
.
Presently the pharmaceutical market is targeted towards
amino-acids and peptides as potent therapeutics are being
preferred over other drug molecules due to their target specificity,
safety profiles, reduced immunogenicity, higher water solubility
and improved bioavailability with additional delivery method
[3]. Peptides like exenatide (Incretin mimetics), pramlintide
(Amylin derivatives) Lixisenatide, Liraglutide have been approved
for the treatment of diabetes mellitus [4]. Lixisenatide also showed
a cardioprotective effect in rodent models [5]. Kim et al. studied
that a hexapeptide (Gly-Ala-Gly-Val-Gly-Tyr) showed improve-
ment in glucose transport and also exerted beneficial lipid
metabolic effects [6]. Amino acids like glycine mostly reduce the
superoxide anion radical which decreases the protein carbonyl and
lipid per-oxidation and protects vascular tissues against oxidative
Abbreviations: BGL, blood glucose level; CPE, chlorophosphate ester; DCM, diabetic
cardiomyopathy; DPPH, 1,1-diphenyl-2-picryl-hydrazyl; DNSA, 3,5-dinitro salicylic
acid reagent; ECG, electrocardiogram; IR, infra-red; PQRST, wave pattern; STZ,
streptozotocin; TLC, thin layer chromatography; TZD, thiazolidinedione.
*
Corresponding author.
E-mail address: deepanwita.maji@gmail.com (D. Maji).
http://dx.doi.org/10.1016/j.biopha.2017.01.160
C
0753-3322/ꢀ 2017 Elsevier Masson SAS. All rights reserved.

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D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
stress by restoring the glutathione biosynthesis and which in turn
increased the availability of nitric oxide (NO) and provided
cardioprotection in sucrose fed rat [7]. Ajjan and Grant concluded
that TZDs have a wide range of activity and seemed to be able to alter
many CV risk factors by ameliorating insulin resistance and
enhancement of hyperglycemia, in addition to its TZDs also provided
a positive effect on lipid profile, blood pressure, inflammation and
coagulation [8]. Sekhar et al., Bahmani et al., McCarty and
DiNicolantonio studied various beneficial effects of glycine [9–11].
The available information on thiazolidinediones, glycine hybrid
molecules and their therapeutic capability of treating diabetes
mellitus and providing cardioprotection [4,7] made us take this
challenge to develop newer hybrids thiazolidinedione-5-acetic acid–
amino acid and peptide hybrid methyl esters mostly of glycine, which
might be effective as potent antidiabetic with cardioprotection.
1406 (nH–C–S stretching), 1047 (nC–N stretching). ESI-MS (m/z):
174.6 [MꢁH]+; 1H NMR (400 MHz,
2H), 4.632 (t, J = 6 Hz, 1H) A1.
d, ppm. D2O) 3.09 (d, J = 5.6 Hz,
2.1.2. Peptide synthesis (Scheme 2) [14,15]
Step 1: Amino protection using phthalic anhydride as carried
out by following the reported method of Tella et al. and Zav’yalov
et al. to obtain white needle-shaped crystals of phthaloyl glycine
[14,15].
Phthaloyl glycine (II): white fine needle-shaped crystals,
80.5%, mp: 196.6 8C, Rf: 0.85 (BAW::4:1:1), IR (KBr, cmꢁ1
)
3564, 1772, 1729, 1715, 1219, 997.
Step 2: Carbonyl protection (IIIa–IIIf) [16].
Different amino acids methyl esters were prepared as shown in
Fig. 1 and Table 1 following the reported by Li et al. in which amino
acids (1 equiv, 13.79 mmol) were dissolved in 30 mL of methanol,
followed by addition of SOCl2 at 0 8C with continuous stirring, to form a
clear solution, refluxed for 6 h and cooled. The precipitate so obtained
was washed with ether:methanol::5:1, and yielded (IIIa–IIIf).
2. Materials and method
All the chemicals and solvents used were of Rankem, Merck, and
Sigma–Aldrich. Progress in the reactions was monitored by thin-
layer chromatography (TLC) on silica gel plates (60 F254)
HX617152, Merck, Darmstadt, Germany. Spots were visualized
using Ninhydrin solution, ultraviolet light or iodine chamber in
different solvent systems. The peptide synthesis was done using
Liquid phase method as it is cost effective, more feasible due to use
of very common solvents and reagents mentioned in the schemes
below and less tedious in laboratory scale to workup. Melting
points were determined using automated OPTIMELT apparatus
(Stanford Research System, Sunnyvale, CA) and were uncorrected.
FTIR spectroscopy was recorded on FT-IR 8400S (SHIMADZU
Kosyoto Japan). 1H NMR spectra were determined in DMSO-d6
solution using 400 MHz (Varian). Proton chemical shifts were
Phe methyl ester HCl (IIIa): white solid, 75%, mp 158–160 8C,
Rf = 0.87 (50% propanol:water); IR (KBr, cmꢁ1) 3050, 3119,
1752, 1274.
Gly methyl ester HCl (IIIb): white solid, 90%, mp 174–175 8C,
Rf = 0.73 (50% propanol:water); IR (KBr, cmꢁ1) 3015, 2853,
1744, 1268.
Meth methyl ester HCl (IIIc): yellowish white solid, 65%, mp
148–150 8C, Rf = 0.83 (50% propanol:water); IR (KBr, cmꢁ1
)
3050, 3119, 1751, 1257, 900.
Leu methyl ester HCl (IIId): white solid, 79%, mp 153–155 8C,
Rf = 0.70 (50% propanol:water); IR (KBr, cmꢁ1) 3017, 2855,
1742, 1269.
Ser methyl ester HCl (IIIe): white solid, 84%, mp 188–190 8C,
Rf = 0.77 (50%propanol: water); IR (KBr, cmꢁ1) 3372, 3015,
2852, 1726, 1272.
measured in d, using tetramethylsilane (TMS, d = 0.00) as internal
standard and expressed in ppm. Spin multiplicities are given as
singlet (s), doublet (d), triplet (t) and multiplet (m) as well as broad
(b), MALDI-TOF was done using UltrafleXtreme, MALDI-TOF/TOF
(Bruker, Germany) at CRF, IIT, Kharagpur, India.
Tyr methyl ester (IIIf): white solid, 78%, mp 161–163 8C,
Rf = 0.68 (50% propanol:water); IR (KBr, cmꢁ1) 3216, 3112,
3054–3122, 1735, 1247.
Animals were obtained from Central Animal Facility, BIT Mesra.
The study was approved by Institutional animal ethical committee,
Department of Pharm. Sciences and Technology, Birla Institute of
Technology, Mesra (Approval No: BIT/PH/AEC/21/2012).
Steps 3–4: Activation of –COOH group, coupling and deprotec-
tion of the amino group [17,18] was done using chlorophosphate
reagent (CPE) following the method reported by Samanta et al. to
obtain dipeptide methyl esters (Va–Vf) and tripeptide methyl ester
HCl (VIIa–VIIb). 10 mL of CPE reagent (equimolar quantity of
anhydrous ethanol and phosphorous pentachloride 12.50 g, and
0.06 mol were reacted with constant stirring, in anhydrous
condition at 0–5 8C) was added to 1.03 g (5 mmol) phthaloyl
glycine followed by addition of single amino acid esters (IIIa–IIIf,
5 mmol) to form a clear solution. Triethylamine (TEA) was added to
the above mixture (pH 7) and then poured over crushed ice and left
for 6 h at 0 8C. to obtained IVa–IVf. To which .0.01 mL of hydrazine
hydrate (80%) in 20 mL of ethanol was added and heated for 2 h,
cooled, acidified with conc. HCl cooled and left overnight allowing
phthaloyl-hydrazide crystals to separate and removed by filtration.
Excess solvent was removed by vacuum distillation followed by
2.1. Synthesis
The synthesis was performed in three parts:
(a) Synthesis of 2,4-thiazolidinedione-5-acetic acid (I)
(b) Peptide synthesis (II. IIIa–IIIf, IVa–IVf, Va–Vf, VIa–VIf, VIIa–VIIf)
(c) Synthesis of hybrid compounds (VIIIa–VIIIf, IXa–IXb, Xa–Xb).
2.1.1. Synthesis of thiazolidinedione-5-acetic acid (Scheme 1) [12,13]
3.80 g (50 mmol) of thiourea and 4.90 g (50 mmol) of maleic
anhydride were reacted in presence of 25 mL of concentrated
hydrochloric acid (conc. HCl) refluxed for 5 h, followed by cooling to
obtain white crystals of 2-(2,4-dioxothiazolidin-5-yl)acetic acid
(I). White crystals, 69.95%, mp: 168 8C, Rf: 0.86 (CHCl3:CH3OH::4:9);
IR (KBr) cmꢁ1: 3047–3117 (
nO–H stretching), 1700 (nC O stretching),
O
S
O
O
HN
O
O
Conc.HCl
NH2
+
O
Reflux for
H2N
S
OH
5-6 hrs
Maleic anhydride
Thiourea
(a)
2-(2,4-dioxothiazolidin-5-yl) acetic acid
I
Scheme 1. Schematic diagram for the synthesis of thiazolidinedione-5-acetic acid.

D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
1165
Scheme 2. General scheme for synthesis of peptides.
crystallization from aqueous ethanol to obtain dipeptide methyl
esters (Va–Vf) and tripeptide methyl esters (VIIa–VIIb).
Gly-Tyr methyl ester HCl (Vf): white solid, 71%, mp 200–
202 8C, Rf = 0.46 (50% propanol:water); IR (KBr, cmꢁ1
)
3041,31451674,1725, 1762, 864.
Gly-Phe methyl ester HCl (Va): white solid, 73%, mp: 114–
116 8C, Rf = 0.58 (50% propanol:water); IR (KBr, cmꢁ1) 3054,
3140, 1615, 1740–1764, 777.
Gly-Gly-Phe methyl ester (VIIa): White fluffy crystals, 66%, mp
164–166 8C, Rf = 0.35 (50% propanol:water); IR (KBr, cmꢁ1
)
3055, 3210, 1610, 1735, 1747, 798.
Gly-Gly methyl ester HCl (Vb): White solid, 65%, mp 153–
155 8C, Rf = 0.45 (50% propanol:water); IR (KBr, cmꢁ1) 3035–
3110, 1590, 1725–1742, 783.
Gly-Gly-Gly methyl ester (VIIb): White fluffy crystals, 70%, mp
141–143 8C, Rf = 0.42 (50% propanol:water); IR (KBr, cmꢁ1
)
3063, 3195, 1621, 1738, 1754, 801.
Gly-Meth methyl ester HCl (Vc): white crystals, 60%, mp 142–
143 8C, Rf = 0.50 (50% propanol:water); IR (KBr, cmꢁ1) 3058,
3117, 1623, 1735–1740, 861.
Gly-Leu methyl ester HCl (Vd): pale yellowish crystals, 68%, mp
193–195 8C, 0.42 (50% propanol:water); IR (KBr, cmꢁ1) 3150,
1630, 1735, 756.
Gly-Ser methyl ester HCl (Ve): white solid, 54%, mp 164–
166 8C, Rf = 0.61 (50% propanol:water); IR (KBr, cmꢁ1) 3078,
1601, 1755, 786.
2.1.3. Synthesis of Hybrid compounds: (VIIIa–VIIIf), (IXa–IXf) and
(Xa–Xb) [14]
1.0 g (1 equiv, 0.005 mmol) of 2,4-thiazolidinedione-5-acetic
acid was dissolved in 10 mL of dioxane:water (1:1), 1 mL of 1 N
NaOH with stirring for 20 min. Further 0.6 mL (1.6 equiv,
0.008 mmol) of SOCl2 was added at 0–5 8C with continuous
stirring for 4 h at room temp till a clear solution was formed. To the

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D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
above clear solution single amino acid esters (IIIa–IIIf), dipeptide
methyl esters (Va–Vf) and tripeptide methyl esters (VIa–VIb) were
added, refluxed for the 1 h excess of solvent was removed to form
VIIIa–VIIIf, IXa–IXb and Xa–Xb respectively. The reaction scheme
has been outlined in Scheme 3.
145.1 (188ꢁCONH). 174.1, 126.0, 116, 74 are due to cleavage of
the heterocycle.
SSDMA5 (VIIIe): white solid, 77%, mp 171–172 8C, Rf = 0.58
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1): 3121, 1620, 1700, 922.
d
12.73 (s,b,1H), 11.95 (s,b,
1H), 7.0–7.9 (m,5H), 4.63 (t,1H), 4.65 (s,1H), 3.512 (s,3H), 3.039
(d,2H), 2.30 (t,1H), 2.95 (d,2H); EI (mass spectroscopy) m/z:
275.1 (Mꢁ1), 244 (275ꢁOCH3), 216.4 (244ꢁCO).
SSDMA1 (VIIIa): white crystals, 78%, mp 166–168 8C, Rf = 0.73
(CHCl3:methanol) 4::6, IR (KBr, cmꢁ1) 3054, 3122, 1700, 1735,
1350, 923; 1H NMR (400 MHz, ppm. DMSO):
d
12.02 (s, 2H),
MALDI-TOF: 275.4 [Mꢁ1] and 276 [M].
7.2–7.9 (m, 5H), 3.68 (s, 3H), 4.67 (t, 1H), 3.43, 2.99 (d, 2H), 4.08
(t, 1H), 3.04–3.40 (m, 1H), 2.89 (d, 2H).
SSDMA6 (VIIIf): white solid, 69%, mp 164–166 8C, Rf = 0.58
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
d 11.9 (s, 1H), 11.5.5 (s, b, 1H),
n
, cmꢁ1): 3121, 1620, 1700, 922;
EI (mass spectroscopy) m/z: 337.2 (M+1), 321.1 (MꢁNH3),
MALDI-TOF 335.5 [Mꢁ1], 336.5 [M] and 337.5 [M+1].
SSDMA2 (VIIIb): white solid, 85%, mp 158–160 8C, Rf = 0.74
(CHCl3:methanol) 4::6, IR (KBr, cmꢁ1) 3024, 1699, 1744, 915;
9.50 (s, b,1H), 7.0–7.9 (m,5H), 4.68 (t, 1H), 2.981 (d,2H), 4.08
(t, 3H), 3.9 (d,2H), 3.432 (s, 3H). EI (mass-spectroscopy)
m/z: 352.8 (M+1), 322.2 (353ꢁOCH3), 294.1 (322ꢁCO), 187
(294ꢁCH2C6H5OH).
1H NMR (400 MHz, ppm DMSO):
d 12.42 (s,1H), 11.93 (s,1H),
3.61 (s,3H), 4.64 (t,1H), 2.99 (d, 2H); EI (mass spectroscopy) m/
z: 247.2 (M+1).
SSDMA13 (IXa): white solid, 71%, mp 153–155 8C, Rf = 0.61
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1) 3046, 1698, 1735, 922.
SSDMA3 (VIIIc): pale yellowish white solid, 72%, mp 130–
131 8C, Rf = 0.68 (CHCl3:methanol) 4::6, IR (KBr, cmꢁ1): 3110,
d 12.01 (s,1H), 10.95 (s,1H),
7.927 (s,1H), 7.855 (m,5H), 3.021 (d,2H), 4.64 (t,1H), 3.671
1746, 1735, 796. 1H NMR (400 MHz, ppm. DMSO):
d
12.12
(s,3H). EI (mass-spectroscopy) m/z: 393 (M), 243 [393ꢁ(OCH3,–
(s,1H), 8.43 (s,1H), 3.85 (s,3H), 4.63 (t,1H), 2.99 (d,2H), 4.25
(t,1H), 2.47 (m,2H), 2.63 (t,2H), 2.01 (s,3H), 3.07 (d,2H); EI
(mass-spectroscopy) m/z: 321.2 (M+1), 289 (320ꢁOCH3), 260.1
(289ꢁCO), 185 [260ꢁ(CH2–CH2–SH–CH)], 156 (185ꢁCO), 128
(158ꢁNHCH2) 164, 116, 102, 74 are due to cleavage of the
heterocycle.
CO,–CH2C6H5)],
213
(243ꢁNHCH3),
186
(213ꢁCO),
113 [186ꢁ(–CH2,–NH3,–CH2CO)], 116, 102, are due to cleavage
of the heterocycle. MALDI-TOF: 393.7 [M+1].
SSDMA14 (IXb): white solid, 79%, mp 155–157 8C, Rf = 0.58
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1): 3024, 1699, 1744, 915.
d
12.018 (s,1H), 8.319 (s, 1H),
SSDMA4 (VIIId): white solid, 65%, mp 143–145 8C, Rf = 0.76
4.63 (t,1H), 3.005 (d,2H), 4.039 (m,1H), 3.63 (s,3H). EI (mass
spectroscopy) m/z: 303 [M], 226 [303ꢁ(OCH3,CO,H2O)],
168 [226ꢁ(NHCH2,CO)], 138 [168ꢁNHCH2], 110 [138ꢁCO],
116, 102, 74 are due to cleavage of the heterocycle.
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1): 3391, 1683, 1731, 816;
d
, 12.89 (s,1H), 12.01 (s,1H),
4.65 (t,1H), 4.61 (d,2H), 3.15 (s,3H), 2.42 (t,2H), 1.2 (m,1H), 1.15
(d,3H).; EI (mass spectroscopy) m/z: 302 (M), 301.1 (Mꢁ1),
271.2 (302ꢁOCH3), 243 (271ꢁCO), 188 [243ꢁCH2CH(CH3)CH3],
SSDMA15 (IXc): white solid, 66%, mp 135–137 8C, Rf = 0.70
(CHCl3:methanol) 4::6, IR (KBr,
n
, cmꢁ1): 3160–3200, 1695,
Scheme 3. General scheme for the synthesis of hybrids [19].

D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
1167
1728, 918. 1H NMR (400 MHz, ppm. DMSO):
d 12.015 (s,1H),
10.215 (s,1H), 8.292 (s,1H), 4.64 (m,1H), 3.52 (d,2H), 3.05
(d,2H), 4.59 (t,1H), 2.45 (t,2H), 1.95 (m,2H), 1.99 (s,3H), 3.65
(s,3H). EI (mass spectroscopy) m/z: 377 [M], 318 [377ꢁ(OCH3,
CO)],
243
[318ꢁCH2CH2SHCH3],
226
[243ꢁNH3],
183 [226ꢁ(C2H2OH)], 113 [183ꢁ(–CONH,–CHCH2)], 116, 102,
74 are due to cleavage of the heterocycle.
Fig. 1. General structure of hybrids.
SSDMA16 (IXd): white solid, 66%, mp 137–138 8C, Rf = 0.67
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1): 3048, 1696, 1734, 788.
EI (mass spectroscopy) m/z; 360 [M], 345 [360ꢁ(–CH3)],
183 [360ꢁ(–COO,–NHCH2CO,–H2O,–CONH)], 169 [183ꢁ(–CH2)],
112 [169ꢁ(–CONH,–CH2)], 116, 104, 102, 74 are due to cleavage of
the heterocycle.
d
12.07 (s,1H), 8.89 (s,b,1H),
8.85 (s, b,1H), 4.68 (t,1H), 4.09 (d,2H), 4.61 (t,1H), 2.48 (d,2H),
4.05 (d,2H), 1.21 (m, 1H), 1.75 (d,3H). EI (mass spectroscopy)
m/z: 359 [M], 243 [Mꢁ(–OCH3,–CO,–CH2CH(CH3)CH3)],
187 [243ꢁ(–NHCH,–CO)], 160 [187ꢁ(CHN)], 118 [160ꢁ(–CH2CO)],
CH2CO)], 102 [118ꢁ(–O)], 104, 74 are due to cleavage of the
heterocycle.
2.2. Pharmacological activity
SSDMA17 (IXe): white solid, 66%, mp 153–151 8C, Rf = 0.67
Pharmacological activity has been divided into four subparts as
follows.
(CHCl3:methanol) 4::6, IR (KBr,
1740, 921. 1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1): 3050–31161, 1699,
d
12.02 (s, 1H), 8.29
(s, 1H), 7.9 (s, 1H), 4.612 (t, 1H), 3.69 (s, 3H), 3.21 (s, 2H), 3.33 (t,
1H), 4.64 (s, 1H), 3.05 (d, 2H). EI (mass-spectroscopy) m/z:
333.1 [M], 274 [Mꢁ(–OCH3,–CO)], 243 [Mꢁ(CH2OH)],
163 [243ꢁ(CH2CONHCH)], 148 [163ꢁ(NH)], 106 [148ꢁ(CO,–
CH2)], 116, 104, 102, 74 are due to cleavage of the heterocycle.
SSDMA18 (IXf): white solid, 66%, mp 166–168 8C, Rf = 0.59
2.2.1. In vitro antioxidant study (DPPH scavenging activity)
The free radical scavenging activity was measured in vitro by
1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay using different con-
centrations (10–250
mg/mL) of test drugs (T1–T13) in methanol
and 1 mL of the (0.3 mM) DPPH solution. The absorbance was
measured at 517 nm following the method described by Blois, and
the IC50 was reported [20]. All analyses were performed in
triplicates.
(CHCl3:methanol) 4::6, IR (KBr,
n
, cmꢁ1) IR (KBr,
n
, cmꢁ1): 3050,
12.01
1620, 1700, 922. 1H NMR (400 MHz, ppm. DMSO):
d
(s,1H), 8.291 (m,1H), 8.044 (m,1H), 4.64 (t,1H), 3.45 (d,2H),
7.862 (s,1H), 7.63–7.21 (m,5H), 3.05 (s,2H), 3.63 (s,3H), 3.03 (d,
2H,–CH2 of tyrosine).
2.2.2. In vitro antidiabetic activity (glucose uptake by yeast cells)
Yeast cells were prepared according to the method reported by
Cirillo in 1963 [21]. Different concentrations of test drug were
EI (mass spectroscopy) m/z: 409 [M], 243 [Mꢁ(–COOCH3,–
CH2C6H5OH)],
163
[243ꢁ(–NHCH,–C O,–NHCH2,–C O)],
freshly prepared (10, 20, 40, 80, 100, 200
mL/mL). 3,5-Dinitro
115 [163ꢁ(C O)], 102 [115ꢁ(–CH)].
salicylic acid (DNSA) reagent was added and absorbance measured
at 540 nm, pioglitazone HCl was used as standard drug [22].
SSDMA49 (Xa): white solid, 66%, mp 138–140 8C, Rf = 0.83
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1): 3117, 1599, 1700, 786.
d
12.51 (s,1H), 12.01 (s, 1H),
2.2.3. Acute toxicity study
11.89 (s,1H), 4.627–4.702 (m,1H), 3.01 (d,2H), 4.09 (s,2H), 4.06
(s,2H), 4.52 (t,1H), 3.06 (d,2H), 7.33–7.44-7.19 (m,5H), 3.28
(s,3H).
The acute toxicity study of the thiazolidinedione-5acetic acid
hybrids was performed according to the OECD guidelines in adult
female albino mice (Swiss strain) weighing between 25 and 30 g.
6 mice received a single dose of 300 mg/kg body weight (b.w),
orally of 3 subseries of synthesized drugs.
EI (mass-spectroscopy) m/z: 450 [M], 254 [450ꢁ(–OCH3,–CO,–
CH2C6H5,–NHCH,–H2O)],
127 [183ꢁ(CONH,–CH2)], 114 [127ꢁ(–CH)], 116, 104, 102,
74 are due to cleavage of the heterocycle.
183
[254ꢁ(–NHCH2CO,–CH2)],
2.2.4. In vivo antidiabetic activity
SSDMA50 (Xb): white solid, 66%, mp 141–143 8C, Rf = 0.83
2.2.4.1. Induction of diabetes in Wistar (male) rats. Wistar (male)
rats weighing about 160–250 g was used. Animals were main-
tained at 22 ꢂ 2 8C with 12 h light:12 h dark cycle. The rats were
provided commercial standard pelleted diet and tap water ad libitum.
Each experimental group consisted of 4 animals each.
(CHCl3:methanol) 4::6, IR (KBr,
1H NMR (400 MHz, ppm. DMSO):
n
, cmꢁ1): 3037, 1606, 1696, 903.
d
12.02 (s,1H), 8.29 (m,1H),
7.45 (s,1H), 7.33 (s,1H), 4.642–4.612 (m,1H), 3.61 (d,2H), 3.911
(s,2H), 3.05 (s,2H), 3.02 (s,2H), 3.6 (s,3H–OCH3).
Table 1
List of the different amino acids and peptides attached to 2,4-thiazolidinedione-5-acetic acid and their codes as used in the pharmacological activity.
Compound
Codes used in pharmacological activity
Molecular formula
Molecular weight
X
R
SSDMA1 (VIII a)
SSDMA2 (VIII b)
SSDMA3 (VIII c)
SSDMA4 (VIII d)
SSDMA5 (VIII e)
SSDMA6 (VIII f)
SSDMA13 (IX a)
SSDMA14 (IX b)
SSDMA15 (IX c)
SSDMA16 (IX d)
SSDMA17 (IX e)
SSDMA18 (IX f)
SSDMA49 (X a)
SSDMA50 (X b)
T1
C15H16N2O5S
C8H10N2O5S
C11H16N2O5S2
C14H18N2O5S
C9H12N2O6S
C15H16N2O6S
C17H19N3O6S
C10H13N3O6S
C13H19N3O6S2
C14H21N3O6S
C11H15N3O7S
C17H19N3O7S
C19H22N4O7S
C12H16N4O7S
336.36
246.03
320.39
302.35
276.04
352.05
393.41
303.29
377.44
329.40
333.32
409.41
450.47
360.34
Phe
–OCH3
–OCH3
T2
Gly
T3
Met
T4
Leu
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
T5
Ser
T6
Tyr
T7
Gly-Phe
Gly-Gly
Gly-Met
Gly-Leu
Gly-Ser
Gly-Tyr
Gly-Gly-Phe
Gly-Gly-Gly
T8
T9
T10
T11
T12
T13
T14

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D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
Selected rats were kept in overnight fasting for 12 h before
The synthesis of the hybrids was performed as outlined in
Materials and methods following modified Vertesaljai et al.
method [19].
The characterization and spectral data of hybrids of peptides are
critical and complex. Some have been discussed as under [28–32].
induction. A single intraperitoneal (i.p) injection of streptozotocin
(STZ, 60 mg/kg, body weight (b.w), dissolved in freshly prepared
0.05 M citrate buffer (pH = 4.5)) was given 15 min after i.p
administration of nicotinamide (120 mg/kg, b.w, dissolved in
normal saline). Blood glucose level was monitored by tail prick
method consecutively on day 3 and day 7 using AccuSure
Glucometer, Medical Technology Promedt Consulting, Germany.
Animals with high blood glucose level between 200 and 350 mg/dL
in fasting were considered to have experimental diabetes [23–25].
The animals were divided into five groups (n = 4). G-I (Normal
Control), G-II (Diabetic Control), G-III (Diabetic+Pioglitazone), G-IV
(Diabetic+T1), G-V (Diabetic+T4), G-VI (Diabetic+T5), G-VII (Dia-
betic+T7), G-VIII (Diabetic+T9) and G-IX (Diabetic+T13). All
animals received 30 mg/kg b.w. of the standard and test drugs
orally for 14 days and change in the serum blood glucose level was
observed on the day 0, day 7, day 14 of treatments.
1. In the case of hybrids, a much stronger band was observed
around 3113–3310 cmꢁ1 due to –NH stretching of 2,4
thiazolidinedione moiety and –NH stretching of the secondary
amides. Strong absorption bands were seen at 1585–1700 cmꢁ1
due to –C O stretch of secondary amide and strong and intense
bands at 1720–1770 cmꢁ1 were noticed due to the –C
stretch of esters as well as –C stretch of the 2,4-
O
O
thiazolidinedione-5-acetic acid moiety. Sharp bands at 1565–
1475 cmꢁ1 were seen distinctly due to –NH deformation of
secondary amides. In hybrids containing methionine a weak
band was seen at 2482 cmꢁ1
.
2.
d
values of 11.5–12.5 correspond to the singlet, broad peak of –
2.2.5. In vivo cardioprotective activity
NH proton of thiazolidinediones. 8.00–10.0 correspond to the
d
Animals from groups I, II, III, IV, VII, and IX were selected for the
cardioprotective studies and the ECG was recorded using Biopac
Student Lab PRO System. The data and power spectrum analyses
were done by AcKnowledge 4 software (Biopac System Incorpo-
ration, USA) [26,27].
proton of the amide bonds (–CONH).
Phenolic protons were observed at
SSDMA6 and SSDMA18 respectively. Sharp peaks at
respond to the proton of –OH in SSDMA5 and SSDMA17 due to
the presence of serine combinations.
d
9.56 and 11.0 as in
4.64 cor-
d
Aromatic protons were seen as multiplets around
d 7.1–7.8
in SSDMA1, SSDMA13, SSDMA49, SSDMA6, and SSDMA18. The
protons of the methyl ester (–OCH3) were merged and observed
3. Result and discussion
as sharp peaks at
d 3.5 to 3.9.
3. Fragmentation pattern of peptides are unique and follow a
specific pattern as under:
3.1. Chemistry
As per the SAR of the TZDs, for potent Antidiabetic activity,
a molecule should have a polar TZD ring, hydrophobic trunk,
2C atom linker and hydrophobic tail. Here a small library of
14 Thiazolidinedione-5-acetic acids hybrids was synthesized
retaining the head and trunk and replacing the hydrophobic tail
with highly hydrophobic amino acids (phenylalanine, methionine,
and leucine) and less hydrophobic amino-acid (glycine and
tyrosine) and also a polar amino acid serine methyl esters.
Here the –COOH is protected as methyl ester, hence firstly –
OCH3 (MW = 31) is lost, followed by loss of –CO (MW = 28), if any
branching is present, then the loss of the –CH2R0 (R0 = aliphatic
chain, aromatic chain,-SH, etc.) occurs. Further there was loss of –
NH = CHR00 (R00 = H,-alkyl, etc.), then –CO (MW = 28) and this
process get repeated. Sometimes small molecules like: H, H2O, and
NH3 were also released. Dipeptides and tripeptides followed the
above fragmentation pattern as shown in Fig. 2.
Fig. 2. The ECG recording for normal control, diabetic control, standard and the three test groups (T1, T7, T13) for 1800 s using BIOPAC MP 45 data acquisition unit and
associated Laboratory software (BSL PRO), Biopac Systems Incorporation (MS) U.S.A.

D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
1169
Fig. 3. Fragmentation pattern of SSMA13 (T-Gly-Phe methyl ester).
3.2. Pharmacological activity
Fig. 5. Color changes observed during in vitro antidiabetic studies.
3.2.1. In vitro antioxidant activity
Antioxidants are compounds which prevent the process of
oxidation by intervening with the initiation, propagation, and
termination of the free radicals (ROS). The increase in the
availability of ROS can create oxidative stress which may lead to
many degenerative diseases. The harmful effects of these ROS
could be balanced by the endogenous as well as exogenous
antioxidant compounds. The most common method determination
of antioxidant activity is the DPPH (1,1-diphenyl-2-picryl-hydrazyl)
assay. It gives a measure of the H-donating capability of newer
Fig. 4. Bar Graph showing the comparative IC 50 values for Antioxidant Activity, All data are expressed as mean ꢂ SEM. Note: AA = ascorbic acid, T1–T15 = test drugs selected
from SSDMA1 to SSDMA50.
Table 2
Effect of treatment of the synthesized drugs on fasting plasma glucose level in T2DSTZ-NA induced T2DM rat models for 14 days at 30 mg/kg body weight.
Fasting plasma glucose (mg/dl) mean ꢂ SEM
Group No.
Groups
Day 0
Day 7
Day 14
Group I
Normal Control
Diabetic Control
Diabetic+Pioglitazone
Diabetic+T1
101 ꢂ 3.11
102 ꢂ 1.85
98 ꢂ 5.69
Group II
Group III
Group IV
Group V
Group VI
Group VII
GroupVIII
Group IX
309 ꢂ 7.70 a****
301 ꢂ 5.19 bns
284 ꢂ 7.77 bns
301 ꢂ 8.87 bns
310 ꢂ 9.02 bns
307 ꢂ 9.57 bns
305 ꢂ 9.39 bns
298 ꢂ 9.02 bns
336.73 ꢂ 10.59 a****
179.25 ꢂ 11.78 b****
204.75 ꢂ 5.56 b****
280 ꢂ 7.63 b**
360 ꢂ 8.66 a****
137.76 ꢂ 4.79 b****
142 ꢂ 5.51 b****
271 ꢂ 10.18 b****
265 ꢂ 10.21 b****
144.47 ꢂ 5.69 b****
269.25 ꢂ 10.18 b****
156 ꢂ 6.98 b****
Diabetic+T4
Diabetic+T5
281 ꢂ 4.31 b**
Diabetic+T7
222.23 ꢂ 2.75 b****
281 ꢂ 10.88 b**
276.37 ꢂ 10.11 b***
Diabetic+T9
Diabetic+T13
All data are expressed as mean ꢂ SEM (n = 4). All groups compared with diabetic control.
a-group II-IX, compared with control.
b-group III-IX, compared with group II (diabetic control).
****
P < 0.0001.
***
P < 0.001.
**
P < 0.01.
ns
P > 0.05.

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D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
compounds which is accepted by DPPH (purple color) and is
reduced to its hydrazine which results in the yellow color (Fig. 3).
T1 (SSDMA1), T7 (SSDMA13) and T13 (SSDMA49) showed lower
IC50 value of 29.88ꢂ, 23.99 ꢂ 0.88 and 33.83 ꢂ 1.21 respectively as
compared to 48.41 ꢂ 1.12 of ascorbic acid and 38.21 ꢂ 1.31 of
thiazolidinedione-5-acetic acid (TZD-5AA) proving that they have
good scavenging ability better than the standard and heterocycle,
hence can act as good antioxidants to prevent the oxidation process in
cells (Fig. 4).
3.2.2. In vitro antidiabetic activity was carried out using yeast cells
and compounds
Endogenously in T2DM condition the cellular uptake of glucose
is reduced, which increases the blood glucose level. The in vitro
glucose uptake assay by yeast cells (Saccharomyces cerevisiae)
resembles the in vivo diabetic condition which has been used here
to screen the hypoglycemic effect of all synthesized drugs in
comparison of standard pioglitazone.HCl. The glucose in the
external solution reduces the 3,5-dinitrosalisylic acid to 3-amino,
Fig. 6. Bar graph showing the % glucose uptake by yeast cells at different drug concentration by the test drugs T1, T4, T5, T7, T9 and T13 (SSDMA1, SSDMA4, SSDMA5,
SSDMA13, SSDMA15 and SSDMA49). All data are expressed as mean ꢂ SEM.
Fig. 7. ECG wave pattern of the treated groups.

D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
1171
3.2.4. In vivo cardioprotective activity
3.2.4.1. ECG wave pattern analysis. The ECG wave pattern analysis
as depicted in Fig. 7 showed that the diabetic rat when treated with
T1 (SSDMA1) and T7 (SSDMA13) showed similar wave pattern as
normal control rat. It indicates that the molecule T1 and T7 help the
diabetic heart to function almost similarly as the normal heart and
thus may have a cardioprotective effect. It is also evident from the
PQRST wave that these molecules help to maintain and complete
the normal cardiac cycle as the wave patterns of T1 and T7 are
similar to wave pattern of a normal rat. T13 shows ECG wave
pattern similar to pioglitazone treated group, where the R and T are
almost of the same amplitude, which is different from the normal
PQRST wave pattern.
3.2.4.2. EGC spectrum analysis. The digitized ECG spectra were
analyzed in frequency domain to compare the frequency spectrum
of normal, diabetic and different drug treated groups. As the
recording setup considered for the evaluation was at the frequency
band width of 0.5–35 Hz, so it was not filtered further for the
removal of high-frequency noise. However before analyzing the
spectrum, the complete set of recorded waveform was passed
through 1 Hz high pass filter to remove the motion effects. Five
ECG waves were considered for spectral analysis. Ten such spectra
were calculated, analyzed and compared.
It was observed from Fig. 8 that almost in all the conditions two
peaks are obtained. One at the low-frequency range of about 8 Hz
and the other at a higher range of 25 Hz. In diabetic condition the
spectrum is very much depressed while the high energy pattern
was achieved by all the drugs similar to normal. T1 and T7 are
similar to the normal spectra where the high-frequency compo-
nent is less, while T13 has a spectrum similar to the standard
treated.
Fig. 8. EGC spectrum analysis of the treated groups.
5-nitro salicylic acid which is observed by the change in color. The
unutilized glucose present in the external reacts with DNSA
reagent to give brownish orange color, intensity of this color
decreases as more glucose is taken up by the drug, thus decreasing
the amount of free glucose in the external solution [33].
T1, T4, T5, T7, T9 and T13 (SSDMA1, SSDMA4, SSDMA5,
SSDMA13, SSDMA15 and SSDMA49) showed % glucose uptake of
39.23 ꢂ 0.18, 36.683 ꢂ 1.92, 37.731 ꢂ 2.00, 38.19 ꢂ 1.16, 36.11 ꢂ 0.23
and 38.90 ꢂ 0.09 as compared to 42.87 ꢂ 1.36 of standard pioglitazone
hydrochloride and 33.33 ꢂ 1.16 of heterocycle TZD-5AA, which was
confirmed by the change in the intensity of color as seen in Figs. 5 and 8. As
the % glucose uptake by TZD-5AA was less so it was excluded from in vivo
studies and, rest T1, T4, T5, T7, T9 and T13 these were included in the in
vivo antidiabetic activity.
3.2.3. In vivo antidiabetic activity
3.2.4.3. Heart rate variability (HRV) spectrum. Fig. 9 shows the HRV
spectrum of a normal rat with one high broad peak towards the low
frequency and a small notch towards the high frequency. Almost
similar spectral pattern were observed in all the subjects in the
experiment. However in T7 and T1 treated groups, the pattern
tends towards lowering the energy. T7 (SSDMA13) has a high peak
in the low-frequency region with a very small notch in the high-
frequency region.
Study was done in STZ-NA-induced T2DM rat models for
14 days at 30 mg/kg body weight dose of each drug.
From Table 2 it is inferred that all the six compounds were
significantly effective in lowering the blood glucose level on the
14th day of the study. T1, T7, and T13 show a consistent and
significant decrease in BGL in both 7th day and 14th day of the
study (Fig. 6).
Fig. 9. Heart rate variability of ECG wave pattern of (a) normal rat, (b) diabetic rat, (c) pioglitazone-treated rat, (d) T1 treated rat, (e) T7 treated rat, (f) T13 treated rat.

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D. Maji, S. Samanta / Biomedicine & Pharmacotherapy 88 (2017) 1163–1172
[6] E.D. Kim, E. Kim, J.H. Lee, C.K. Hyun, Gly-Ala-Gly-Val-Gly-Tyr, a novel synthetic
peptide, improves glucose transport and exerts beneficial lipid metabolic
effects in 3T3-L1 adipoctyes, Eur. J. Pharmacol. 650 (1) (2011) 479–485.
[7] A. Ruiz-Ramirez, E. Ortiz-Balderas, G. Cardozo-Saldana, E. Diaz-Diaz, M. El-
Hafidi, Glycine restores glutathione and protects against oxidative stress in
vascular tissue from sucrose-fed rats, Clin. Sci. (Lond.) 126 (1) (2014) 19–29.
[8] R.A. Ajjan, P.J. Grant, Cardiovascular disease prevention in patients with type
2 diabetes: the role of oral anti-diabetic agents, Diabetes Vasc. Dis. Res. 3 (3)
(2006) 147–158.
[9] R.V. Sekhar, S.V. McKay, S.G. Patel, A.P. Guthikonda, V.T. Reddy, A.
Balasubramanyam, F. Jahoor, Glutathione synthesis is diminished in patients
with uncontrolled diabetes and restored by dietary supplementation with
cysteine and glycine, Diabetes Care 34 (1) (2011) 162–167.
3.2.4.4. Heart rate analysis. The heart rate analysis was done by
manually counting the number of the waveform in 30 s in at
different time intervals. Diabetic rat showed a maximum heart rate
of 343.19 ꢂ 11.19, while T7 showed a heart rate of 182 ꢂ 5.77 which
was similar to normal rat with a heart rate of 175 ꢂ 3.80.T1 and T13
showed heart rate 210.42 ꢂ 7.80 and 210.40 ꢂ 11.15 similar to the
standard (pioglitazone) treated with a heart rate of 195 ꢂ 4.54.
4. Conclusion
[10] F. Bahmani, S.Z. Bathaie, S.J. Aldavood, A. Ghahghaei, Glycine therapy inhibits
the progression of cataract in streptozotocin-induced diabetic rats, Mol. Vis.
18 (2012) 439.
Among the 14 synthesized hybrids, SSDMA1 (T1, TZD-5AA-Phe
methyl ester), SSDMA13 (T7, TZD-5AA-Gly-Phe methyl ester) and
SSDMA49 (T13, TZD-5AA-Gly-Gly-Phe methyl ester) showed
significant antidiabetic activity while SSDMA1 and SSDMA13
showed both antidiabetic activity and were proposed to show
cardioprotective activity. Pioglitazone HCl has been used as the
control molecule without the peptide fragment and compared
with the hybrids in the biological studies. Thus, it was evident
from the study that incorporation of glycine and phenylalanine
to the thiazolidinediones moiety retains its antidiabetic property,
at the same time restores the ECG towards normal in diabetic rats,
hence may be helpful in preventing development of diabetic
cardiomyopathy.
[11] M.F. McCarty, J.J. DiNicolantonio, The cardiometabolic benefits of glycine: Is
glycine an ‘antidote’ to dietary fructose? Open Heart 1 (1) (2014) e000103.
[12] S.G. Alegaon, K.R. Alagawadi, New thiazolidinedione-5-acetic acid amide
derivatives: synthesis, characterization and investigation of antimicrobial and
cytotoxic properties, Med. Chem. Res. 21 (6) (2011) 816–824.
[13] B. Zimenkovskii, R. Kutsyk, R. Lesyk, V. Matyichuk, N. Obushak, T. Klyufinska,
Synthesis and antimicrobial activity of 2,4-dioxothiazolidine-5-acetic acid
amides, Pharm. Chem. J. 40 (6) (2006) 303–306.
[14] A.C. Tella, S.O. Oguntoye, W.A. Osunniran, R.O. Arise, Coordination compounds
of n-phthaloylglycine and n-phthaloyltyrosine and their antimicrobial
activities, Elixir Appl. Chem. 45 (2012) 7620–7623.
[15] S. Zav’yalov, O. Dorofeeva, E. Rumyantseva, L. Kulikova, G. Ezhova, N.
Kravchenko, A. Zavozin, Synthesis of N-phthaloyl derivatives of amino acids,
Pharm. Chem. J. 36 (8) (2002) 440–442.
[16] J. Li, Y. Sha, A convenient synthesis of amino acid methyl esters, Molecules 13
(5) (2008) 1111–1119.
[17] S. Samanta, Novel orally administrable anti-diabetic compounds, process for
producing them and therapeutic compositions containing the same – published
in Patent Journal, India, October 2006.
[18] J. McNulty, V. Krishnamoorthy, A. Robertson, Direct formation of esters and
amides from carboxylic acids using diethyl chlorophosphate in pyridine,
Tetrahedron Lett. 49 (44) (2008) 6344–6347.
Thus, this study motivates us to explore further various amino
acid and peptide hybrids which may be effective dually with fewer
side effects and toxicity and thus provide robust medicines to the
ailing diabetic patients.
[19] P. Vertesaljai, S. Biswas, I. Lebedyeva, E. Broggi, A.M. Asiri, A.R. Katritzky,
Synthesis of taurine-containing peptides, sulfonopeptides, and N- and O-
conjugates, J. Org. Chem. (2014) 2688–2693.
Funding
We thank UGC for financial support during experiment under
UGC-MRP project.
[20] G. Marinova, V. Batchvarov, Evaluation of the methods for determination of
the free radical scavenging activity by DPPH, Bulg. J. Agric. Sci. 17 (1) (2011)
11–24.
[21] V.P. Cirillo, Mechanism of glucose transport across the yeast cell membrane, J.
Bacteriol. 84 (3) (1962) 485–491.
Acknowledgements
[22] M. Bhutkar, S. Bhise, In vitro hypoglycemic effects of Albizzia lebbeck and
Mucuna pruriens, Asian Pac. J. Trop. Biomed. 3 (11) (2013) 866–870.
[23] A. Aboonabi, A. Rahmat, F. Othman, Antioxidant effect of pomegranate against
streptozotocin-nicotinamide generated oxidative stress induced diabetic rats,
Toxicol. Rep. 1 (2014) 915–922.
[24] Y. Nayak, V. Hillemane, V.K. Daroji, B. Jayashree, M. Unnikrishnan, Antidiabetic
activity of benzopyrone analogues in nicotinamide-streptozotocin induced
Type 2 diabetes in rats, Sci. World J. 2014 (2014).
[25] J. Chaudhry, N.N. Ghosh, K. Roy, R. Chandra, Antihyperglycemic effect of a new
thiazolidinedione analogue and its role in ameliorating oxidative stress in
alloxan-induced diabetic rats, Life Sci. 80 (12) (2007) 1135–1142.
[26] J. Montesdeoca-Contreras, A. Villa Parra, R. Avila-Campoverde, J. Morales-
Garcia, Implementation results of biosignals acquisition lessons for Biomedical
Engineering Lab, in : 2015 IEEE NW Russia Young Researchers in Electrical and
Electronic Engineering Conference (EIConRusNW), IEEE, (2015), pp. 336–340.
[27] C. Mukherjee, P. Bharti, S.S. Samanta, A comparative analysis on denoising and
QRS peak detection using BIOPAC and MATLAB software, Int. J. Eng. Res.
Technol. 2 (12) (2013) 1527–1536.
[28] R.M. Silverstein, F.X. Webster, D.J. Kiemle, D.L. Bryce, Spectrometric
Identification of Organic Compounds, John Wiley & Sons, 2014.
[29] J.B. Lambert, Introduction to Organic Spectroscopy, Macmillan, New York,
1987, pp. 174–177.
[30] J. Kong, S. Yu, Fourier transform infrared spectroscopic analysis of protein
secondary structures, Acta Biochim. Biophys. Sinica 39 (8) (2007) 549–559.
[31] G.C. Barrett, D.T. Elmore, Amino acids and peptides, The Press Syndicate of
the University of Cambridge, Cambridge, United Kingdom, 2004.
[32] S.A. Trauger, W. Webb, G. Siuzdak, Peptide and protein analysis with mass
spectrometry, J. Spectrosc. 16 (1) (2002) 15–28.
The authors are grateful to Dr. R.K. Sinha and Dr. Yogender
Aggarwal of Department of Bio-Engineering, BIT Mesra for their
untiring help and support for the in vivo cardioprotective studies.
We also acknowledge Dr. Reddy’s Institute of Life Sciences,
Hyderabad for characterization of the synthesized compounds
and Dr. Ajit, Central Research Facility, IIT Kharagpur for the MALDI-
TOF analysis of few compounds.
We would like to thank AARTI Drugs for providing us with the
gift sample of pioglitazone.HCl (API) and Department of Pharma-
ceutical Sciences and Technology, Birla Institute of Technology,
Mesra, for providing the lab facilities.
References
[1] S.A. Hayat, B. Patel, R.S. Khattar, R.A. Malik, Diabetic cardiomyopathy:
mechanisms, diagnosis and treatment, Clin. Sci. 107 (6) (2004) 539–558.
[2] C. Tack, P. Smits, Thiazolidinedione derivatives in type 2 diabetes mellitus,
Neth. J. Med. 64 (6) (2006) 166–174.
[3] K. Sulochana, R. Ge, Developing antiangiogenic peptide drugs for angiogenesis-
related diseases, Curr. Pharm. Des. 13 (20) (2007) 2074–2086.
[4] R. Ghosh, V. Thanawala, V.J. Kadam, Novel peptides: an alternative approach
for the treatment of diabetes mellitus, Curr. Drug Ther. 2 (3) (2007) 196–204.
[5] P. Wohlfart, W. Linz, T. Hu¨bschle, D. Linz, J. Huber, S. Hess, D. Crowther, U.
Werner, H. Ruetten, Cardioprotective effects of lixisenatide in rat myocardial
ischemia-reperfusion injury studies, J. Transl. Med. 11 (1) (2013) 84.
[33] A.V. Gusakov, E.G. Kondratyeva, A.P. Sinitsyn, Comparison of two methods for
assaying reducing sugars in the determination of carbohydrase activities, Int. J.
Anal. Chem. 2011 (2011).