Chemical synthesis, docking studies and biological effects of functionalized 1,3-diaryl-2-propen-1-ones on human colon cancer cells

Article abstract of DOI:10.3329/bjp.v10i1.21699

A series of 1, 3-diaryl-2-propen-1-ones was synthesised in order to obtain a new type of anticancer drug, designed with hybrid features to inhibit colon cancer activated receptor. Based on computational modelling and docking studies, potential inhibitors were synthesised and their biological activity evaluated. The structures of newly synthesized compounds were confirmed by¹HNMR,¹³CNMR and Mass spectrometry. All analogues were evaluated for in vitro cytotoxicity against human colon (caco-2) cancer cell lines. Compounds 1b, 1f-1h, and 2i showed significant cytotoxicity. Chalcones 1b, 1f and 1g were identified as the most potent and selective anticancer agents with IC₅₀ values <1 μg/mL and 1.5 μg/mL, against caco-2 cell line, respectively. In conclusion, this finding confirms the suitability of indolyl chalcone analogues as candidates for further investigation towards the management of colon cancer related diseases.

Full text of DOI:10.3329/bjp.v10i1.21699

BJP
Bangladesh Journal of Pharmacology
Research Article
Chemical synthesis, docking studies
and biological effects of functional-
ized 1,3-diaryl-2-propen-1-ones
on human colon cancer cells

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ISSN: 1991-0088
Chemical synthesis, docking studies and biological effects of
functionalized 1,3-diaryl-2-propen-1-ones on human colon
cancer cells
1
2
Guo-Min Zhu and Guo-Dong Huang
1
Department of Surgery, The First Affiliated Hospital of Nanchang University, Nanchang 330006, China;
Department of Integrated Traditional Chinese and Western Medicine, The First Affiliated Hospital of
2
Nanchang University, Nanchang 330006, China.
Article Info
Abstract
Received:
Accepted:
Available Online:
20 January 2015
20 February 2015
17 March 2015
A series of 1, 3-diaryl-2-propen-1-ones was synthesised in order to obtain a
new type of anti-cancer drug, designed with hybrid features to inhibit colon
cancer activated receptor. Based on computational modelling and docking
studies, potential inhibitors were synthesised and their biological activity
evaluated. The structures of newly synthesized compounds were confirmed
by HNMR, CNMR and Mass spectrometry. All analogues were evaluated
for in vitro cytotoxicity against human colon (caco-2) cancer cell lines.
Compounds 1b, 1f-1h, and 2i showed significant cytotoxicity. Chalcones 1b,
DOI: 10.3329/bjp.v10i1.21699
1
13
Cite this article:
Zhu GM, Huang GD. Chemical syn-
thesis, docking studies and biological
effects of functionalized 1,3-diaryl-2-
propen-1-ones on human colon cancer
1
f and 1g were identified as the most potent and selective anti-cancer agents
with IC50 values <1 µg/mL and 1.5 µg/mL, against caco-2 cell line,
respectively. In conclusion, this finding confirms the suitability of indolyl
cells. Bangladesh J Pharmacol. 2015; chalcone analogues as candidates for further investigation towards the
0: 230-40.g
management of colon cancer related diseases.
1
through a variety of mechanisms for example; cell cycle
Introduction
arrest in the G2 phase (Kim et al., 2005) inhibition of
topoisomerase (Ching et al., 2008) and tubulin polyme-
rization inhibition (Alkasomi., 2009) Another mecha-
nism of action is the inhibition of tyrosine kinases
Various research groups have focused on chemopre-
vention and working on development of new lead
molecules. Usually early detection and focus on impro-
vement of currently used drugs can be very helpful for
curbing the disease. From the available literature it's
clear that the quinoline ring system and their fused
derivatives are significant structural units and present
as substructure in various alkaloids, therapeutics and
synthetic analogues, which exhibit good biological
activities (Larsen et al., 1996; Roma et al., 2000). Various
quinolines derivatives are reported as anti-malarial, anti
(Mulvihill et al., 2008). These results encourage us to
design the molecules containing quinoline ring with
different functional group to assess their biological
activity.
Medicinal chemists are tirelessly exploring for a better
and more suitable cancer therapeutics. Chal-cones (1, 3-
diaryl-2-propen-1-ones), constituting an enone system
between two aromatic rings are an important class of
natural products which are considered as precursors for
various flavonoids and exhibit interesting pharmaco-
logical activities (Stu et al., 1971). Chalcones, originating
from natural and synthetic routes possess several
biological activities, such as cytotoxic (Modzelewska et
-
inflammatory, antiasthmatic, antibacterial, anti-hyper-
tensive and platelet derived growth factor receptor
tyrosine kinase (PDGF-RTK) inhibiting agents (Dube et
al., 1998). A large variety of quinolines are reported to
exhibit substantial anti-cancer activities (Alkasomi et
al., 2010) Quinoline derivative act as anti-cancer agents
This work is licensed under a Creative Commons Attribution 3.0 License. You are free to copy, distribute and perform the work. You must attribute the work in the
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Bangladesh J Pharmacol 2015; 10: 230-240
231
al., 2006) anti-malarial (Dominguez et al., 2005), anti-
leishmanial (Boeck et al., 2006) anti-inflammatory (Yang
et al., 2007), anti-HIV (Cheenpracha et al., 2006), anti-
fungal (Svetaz et al., 2004) and as tyrosine kinase
inhibitors (Neryr et al., 2004). Because of very high
pharmacological interest, these molecules have attract-
ed medicinal chemists to design and synthesize further
large number of chalcones with different functional
groups. In the recent years, the development of anti-
cancer agents was achieved by structural modification
of chalcones to increase their bioavailability and to
study the effect of various substituents on aryl or
heteroaryl rings (Meng et al., 2007).
potent and selective anti-cancer agents with IC50 values
7.4 µg/mL and 7.8 µg/mL, against human colon (Caco-
2) cell line, respectively. Based on computational
modelling and docking studies, potential inhibitors
were synthesised and their biological activity evalua-
ted.
Materials and Methods
Chemistry and instrument
Melting point was determined on a Toshniwal melting
point a p pa r a t u s a nd is uncorrected. IR spectra
were recorded on
spectrophotometer. NMR spectra were obtained in
acetone-d DMSO-d and pyridine-d on Bruker
Avance, 300 MHz instrument using TMS as internal
standard. The chemical shift values are reported in ppm
and coupling constants in Hz. ESI-MS spectra were
recorded on a Perkin Elmer Turbo Mass/Shimadzu LC-
MS. TLC analyses were carried out on precoated
silicage l60 F254 plates (Merck) using solvent system,
hexane: ethyl acetate (7:3). The compounds were
a
PerkinElmer 1719 FT-IR
The heteroaryl rings are widely distributed in nature
and possess a variety of significant biological activities.
The indole ring is an important moiety in many
pharmacologically active compounds in which some
studies related reported for anti-cancer effectiveness
6
,
6
5
a
(Grugni et al., 2006). Some of the individual anti-cancer
compounds in which the indole ring is responsible for
the activity are panobinostat (Prince et al., 2009),
cediranib (Nikolinakos et al., 2008), indole-3-carbinol
(Aggarwal et al., 2005) (Figure 1). Basically, indolyl
visualized by either exposure of TLC plates to I
2
chalcones are not much explored for their anti-cancer
potential (Aggarwal et al., 2005). In the present study,
we have synthesized two different series Figure 2 of
novel indolyl chalcones 1a-j (Scheme 1) and 2a-k
vapours or by spraying with vanillin- sulphuric acid
reagent, followed by heating at 110°C for 15 min. Si-gel,
6
0-120 mesh (spectrochem) was used in the column
chromatography for the purification of metabolites.
HPLC analyses were carried out on waters spherisorb
ODS2 (250 x 4.6 mm i.d., 10 µm) column using binary
gradient elution with acetonitrile and water mobile
(
Scheme 2) and evaluated their anti-cancer activity in
vitro against four human cancer cell lines. Compounds
b, 1f-1h, and 2i showed significant cytotoxicity.
1
Chalcones 1b, 1f and 1g were identified as the most
OH
O
NH
H
N
OH
CH3
O
N
N
H
F
H C
3
N
Indole-3-carbinol
N
O
NH
Cediranib
CH3
N
H
Panobinostat
Figure 1: Anti-cancer drugs having indole ring
phase (70:30) at a flow rate of 0.6 mL /min, column
O
O
temperature of 25º and UV detection at λ230 nm. The
R
R
1
compounds were identified by their spectral IR, ID ( H,
1
3
C, DEPT) and 2D (COSY, HSQC, HMBC) ESIMS)
NMR and ESI/MS analysis.
N
H
N
H
Synthesis of indolyl chalcones, series 1
1
2
Indolyl chalcones 1a-j were prepared by the reaction of
indol-3-carboxaldehyde 5 with appropriate acetophe-
none 4 in presence of NaOH at RT (Scheme 1) (Jeong et
Figure 2: Skeleton of chalcone (ꢀ, ꢁ-unsaturated ketone) respon-
sible for its biological activity

Indole-3-carbinol
2
32
Bangladesh J Pharmacol 2015; 10: 230-240
1
1
R
R
O
A
a
O
CH3
CH3
1
1
4h. R = m-OCH =CH
3
3
3
h. R = m-OH
2
2
1
1
4i. R = p-OCH =CH
i. R = p-OH
2
2
1
1
4j. R = o-OH, p-OCH =CH
j. R = o,p-OH
2
2
OHC
O
NH
B
b
+
R
N
H
CH3
R
O
5
4
1
Scheme 1: Reagents and conditions: A) allyl bromide, acetone, 60°C; B) NaOH, methanol, 1-15 hours, RT
O
R
H C
3
HN
c
C
+
RCHO
N
H
O
6
7
2
2
Scheme 2: Reagents and conditions: c) SOCl , methanol, 1-2 hours, RT
18
C H14FNO.
al., 2004).
Trans-3-(1H-indol-3-yl)-1-(4’-benzyloxyphenyl)-2-
propen-1-one (1b)
The contents of reaction mixture were poured into ice-
cold water and neutralized with dilute hydrochloric
acid. The solid so obtained was filtered, column
chromatographed and recrystallized from ethanol to
afford pure compounds.
Yellow solid; 60%, yield; mp 74-75°C; IR νmax (KBr):
3448, 1562, 1120, 735 (NH), 1654(chalcone C=O), 1523,
1495, 1437 (aromatics) cm-1
1
;
H NMR (300 MHz, acetone-
d ): δ 5.29 (2H, s, H -7’’), 7.24 (2H, m, H-5’, H-6’), 7.27
6
2
Trans-3-(1H-indol-3-yl)-1-(4’-flouro-3’-methylphenyl)-
(
(
1H, m, H-4’’), 7.35 (3H, m, H-10’’, H-11’’, H-12’’), 7.49
2H, m, H-4’, H-5’’), 7.53(2H, m H-9’’, H-13’’), 7.68 (1H,
2
-propen-1-one (1a)
Orange powder; 20% yield; mp 59-60°C; IR νmax(KBr):
d, J=15.6 Hz, H-2), 7.70 (1H, s, H-2’’), 7.72 (1H, d, J=7.8,
2.1 Hz, H-7’), 8.01 (1H, d, J=2.7 Hz, H-2’), 8.08 (1H, m, H
-6’’), 8.10 (1H, d, J=15.6 Hz, H-3), 10.92 (1H, brs, NH);
3
1
422, 1548, 1154, 737 (NH), 1653 (chalcone C=O), 1520,
-1 1
491, 1440(aromatics) cm ; H NMR (300 MHz, acetone-
), 7.19 (1H, d, J=9.3 Hz, H-5’’),
.27 (2H, m, H-5’, H-6’), 7.54 (1H, dd, J=8.1, 1.2 Hz, H-
’), 7.70 (1H, d, J=15.6 Hz, H-2), 7.98 (1H, d, J=2.7 Hz, H
d6): δ 2.35 (3H, s, CH
7
4
3
13C NMR (75 MHz, acetone-d ): δ 70.16 (C-7’’), 112.70 (C
6
-4’), 114.05 (C-1’), 114.28 (C-2’’), 116.85 (C-2), 119.35 (C-
4’’), 120.82 (C-6’’), 121.18 (C-7’), 121.65 (C-6’), 123.29 (C-
5’), 126.04 (C-3’), 128.00 (C-9’’, (C-13’’), 128.22 (C-5’’),
128.85 (C-10’’, C-12’’), 130.04 (C-11’’), 132.38 (C-2’),
137.74 (C-8’), 138.33 (C-1’’), 139.62 (C-3), 141.10 (C-8’’),
159.36 (C-3’’), 189.09 (C-1); ESI-MS, MeOH (Positive):
-
2
2’’), 8.04 (1H, dd, J=8.7, 2.7 Hz, H-6’’), 8.08 (1H, brs, H-
’), 8.11 (1H, d, J=15.6 Hz, H-3), 8.10 (1H, d, J=8.1, 1.2
1
3
Hz, H-7’), 10.90 (1H, brs, NH); C NMR(75 MHz,
acetone-d
6
): δ 14.35 (CH
3
), 113.01 (C-4’), 114.36 (C-1’),
a
a
+
-
1
1
1
1
15.49 (C-5’’), 115.79 (C-2), 121.16 (C-7’), 121.93 (C-6’),
24 19 2
m/z 354 [M+H] , (Negative): 352[M-H] , C H NO .
b
23.61 (C-5’), 126.34 (C-3’), 128.99 (C-6’’), 132.66 (C-2’’),
Trans-3-(1H-indol-3-yl)-1-(anthracenyl)-2-propen-1-
one (1c)
b
32.72 (C-2’), 136.17 (C-1’’), 138.65 (C-8’), 139.36 (C-3),
62.74c (C-3’’), 166.03
c
(C-4’’), 188.37 (C-1)
Yellow powder; 80% yield; mp 108-109°C; IR νmax(KBr):
3395, 1561, 1164, 746 (NH), 1649 (chalcone C=O), 1515,
(
2
a,b,c=interchangable); ESI-MS, MeOH (Positive): m/z
80 [M+H] , 302 [M+Na] , (Negative): 278[M-H] ,
+
+
-

Bangladesh J Pharmacol 2015; 10: 230-240
233
-1 1
-1 1
1
d
483, 1430 (aromatics) cm ; H NMR (300 MHz, acetone-
): δ 7.16 (2H, d, J=7.8 Hz, H-4’’, H-12’’), 7.23 (2H, m, H
1523, 1458, 1420 (aromatics) cm ; H NMR (300 MHz,
DMSO-d ): δ 4.64 (2H, d, J=5.1 Hz, H -7’’), 5.26 (1H, dd,
6
6
2
-
(
5’, H-6’), 7.26 (4H, m, H-5’’, H-6’’, H-10’’, H-11’’), 7.44
1H, d, J=2.1 Hz, H-8’’), 7.51 (1H, dd, J=8.1, 2.1 Hz, H-
J=10.5, 0.9 Hz, Ha-9’’), 5.40 (1H, dd, J=17.4, 1.5 Hz, Hb-
9’’), 6.05 (1H, m, H-8’’), 7.24 (3H, m, H-5’, H-6’, H-4’’),
7.49 (2H, d, J=8.1 Hz, H-4’, H-5’’), 7.54 (1H, s, H-2’’),
7.60 (1H, d, J=15.6 Hz, H-2), 8.03 (1H, d, J=6.6 Hz, H-7’),
4
’), 7.59 (2H, d, J=7.8 Hz, H-3’’, H-13’’), 7.87 (1H, d,
J=15.6 Hz, H-2), 7.89 (1H, brs, H-2’), 8.21 (1H, dd, J=8.1,
.1 Hz, H-7’), 8.55 (1H, d, J=15.6 Hz, H-3), 13.05 (1H,
2
8.06 (1H, d, J=15.6 Hz, H-3), 8.09 (1H, d, J=2.1 Hz, H-2’),
13
13
brs, NH); C NMR (75 MHz, acetone-d
6
): δ 111.65 (C-
7.70 (1H, d, J=8.1 Hz, H-6’’), 9.90 (1H, brs, NH);
NMR (75 MHz, DMSO-d
C
5
1
6
1
1
1
’’, C-11’’), 112.53 (C-4’’, C-12’’), 113.06 (C-4’), 114.23 (C-
6
): δ 69.20 (C-7’’), 113.42 (C-4’),
a
a
’), 116.45 (C-3’’, C-13’’), 121.11 (C-7’), 121.89 (C-2, C-
113.60 (C-1’), 114.44 (C-2’’), 116.31 (C-2), 118.42 (C-9’’),
119.82 (C-4’’), 121.09 (C-7’), 121.59 (C-6’’), 122.07 (C-6’),
123.59 (C-5’), 126.05 (C-3’), 130.72 (C-5’’), 134.10 (C-2’),
134.39 (C-8’’), 138.44 (C-8’), 140.08 (C-3), 140.90 (C-1’’),
159.25 (C-3’’), 189.60 (C-1); ESI-MS, MeOH (Positive):
b
b
’), 123.15 (C-6’’, C-10’’), 123.48 (C-5’), 124.15 (C-8’’),
26.40 (C-3’), 128.15 (C-1’’), 133.50 (C-2’), 138.88 (C-8’),
39.30 (C-3), 155.35 (C-7’’, C-9’’), 155.91 (C-2’’, C-14’’),
c
c
79.72 (C-1) (a,b,c=interchangable); ESI-MS, MeOH
+
-
+
-
(
Positive): m/z 348 [M+H] , 346[M-H] , C25
H17NO.
2
m/z 304[M+H] , Negative: 302[M-H] , C20H17NO .
Trans-3-(1H-indol-3-yl)-1-(benzofuran)-2-propen-1-one
Trans-3-(1H-indol-3-yl)-1-(4’-allyloxyphenyl)-2-
propen-1-one (1i)
(
1d)
Dark brown solid; 40%, yield; mp 59-60°C; IR νmax
Light brown powder; 30%; mp 110-111°C; IR νmax (KBr):
(
KBr): 3395, 1151, 1156, 736 (NH), 1654 (chalcone C=O),
3372 1561, 1205, 736 (NH), 1651 (chalcone C=O), 1511,
-1 1
1470, 1406 (aromatics) cm-1
;
1
H NMR (300 MHz, DMSO-
1
509, 1483, 1427 (aromatics) cm ; H NMR (300 MHz,
): δ 7.11 (2H, m, H-5’, H-6’), 7.35 (1H, d,
J=15.6 Hz, H-2), 7.49 (3H, m, H-4’, H-5’’, H-6’’), 7.53
acetone-d
6
d
6
): δ 4.65 (2H, d, J=5.04 Hz, H -7’’), 5.28 (1H, d, J=10.52
2
Hz, Hb-9’’), 5.42 (1H, d, J=17.21 Hz, Ha-9’’), 6.05 (1H, m,
H-8’’), 7.08 (2H, d, J=8.64 Hz, H-3’’, H-5’’), 7.24 (1H, m,
H-5’, H-6’), 7.53 (1H, m, H-4’), 7.67 (1H, d, J=15.40 Hz,
H-2), 8.06 (1H d, J=15.56 Hz, H-3), 8.09 (2H, m, H-2’, H-
7’), 8.13 (1H, d, J=8.72 Hz, H-2’’), 8.13 (1H, d, J=8.72 Hz,
H-6’’), 9.91 (1H, brs, NH); 13C NMR (75 MHz, DMSO-
(
(
1H, d, J=15.6 Hz, H-3), 7.61 (1H, d, J=2.7 Hz, H-2’), 7.92
1H, dd, J=8.4, 2.1 Hz, H-7’), 8.01 (1H, dd, J=6.9, 2.7 Hz,
H-4’’), 8.12 (1H, dd, J=7.2, 2.4 Hz, H-8’’), 8.62 (1H, s, H-
2
δ 112.92 (C-4’), 113.31 (C-1’), 120.69 (C-2), 121.86 (C-
7
1
3
8
(
2
1
3
’’), 13.05 (1H, brs, NH); C NMR (75 MHz, acetone-d
6
):
a
a
b
d6): δ 68.86 (C-7’’), 113.00 (C-4’), 113.19 (C-1’), 115.02 (C-
3’’, C-5’’), 115.66 (C-2), 118.36 (C-9’’), 120.74 (C-7’),
121.53 (C-6’), 123.07 (C-5’), 125.66 (C-3’), 130.85 (C-6’’),
131.80 (C-1’’), 130.85 (C-2’’), 133.37 (C-2’), 133.65 (C-8’’),
138.06 (C-8’), 138.74 (C-3), 162.05 (C-4’’), 187.76 (C-1);
’), 123.42 (C-6’), 124.71 (C-5’), 125.71 (C-3’, C-2’’),
b
25.91 (C-7’’), 126.66 (C-4’’), 127.96 (C-5’’), 128.72 (C-
c
’’), 129.05 (C-6’’), 131.76 (C-8’’) 133.17 (C-2’), 136.65 (C-
’), 138.47c (C-1’’), 142.74 (C-3), 198.91 (C-1),
a,b,c=interchangable); ESI-MS, MeOH (Positive): m/z
+
-
ESI-MS, MeOH (Positive): m/z 304[M+H]
+
, Negative:
2
88[M+H] , Negative: 286[M-H] , C19H13NO .
-
3
02[M-H] , C20
H17NO
2
.
Trans-3-(1H-indol-3-yl)-1-(4’-chlorophenyl)-2-propen-
-one (1e)
1
Trans-3 -(1 H -indo l -3 -yl )-1 - (4 ’ -ally lox y - 2 ’-
hydroxyphenyl)-2-propen-1-one (1j)
Yellow fluffy crystals, 60% yield, obtained and analysed
by spectroscopic data as described by an earlier method
(
Yellow powder; 30% yield; mp 110-111°C; IR νmax (KBr):
3
569 1559, 1229, 735 (NH), 3380 (OH), 1621 (chalcone
Black., et al 1992).
-1 1
C=O), 1497, 1439, 1369 (aromatics) cm ; H NMR (300
MHz, DMSO-d ): δ 4.65 (2H, d, J=4.92 Hz, H -7’’), 5.29
1H, d, J=10.68 Hz, Hb-9’’), 5.42 (1H, d, J=17.32 Hz, Ha-
Trans-3-(1H-indol-3-yl)-1-(2’-chlorophenyl)-2-propen-
1
6
2
-one (1f)
(
9
’’), 6.04 (1H, m, H-8’’), ), 6.50 (1H, s, H-3’’), 6.58 (1H,
Yellow shiny crystals, 85% yield, obtained and analysed
by spectroscopic data as described by an earlier method
dd, J=8.92, 2.08 Hz, H-5’’), 7.25 (2H, m, H-5’, H-6’), 7.52
dd, J=7.92, 2.52 Hz, H-4’), 7.54 (1H, dd, J=7.92, 2.52 Hz,
H-4’), 7.68 (1H, d, J=15.3 Hz, H-2), 8.11 (1H, dd, J=7.92,
.52 Hz, H-7’), 8.14 (1H, s, H-2’), 8.17 (1H, d, J=15.3 Hz,
(
(Black., et al 1992).
Trans-3-(1H-indol-3-yl)-1-(2’-hydroxyphenyl)-2-propen
2
-1-one (1g)
13
H-3), 8.19 (1H, m, H-6’’), 9.45 (1H, brs, NH); C NMR
(
(
(
(
(
(
[
6
75 MHz,DMSO-d ): δ 69.00 (C-7’’), 113.10 (C-4’), 113.36
Light brown crystals, 55% yield, obtained and analysed
by spectroscopic data as described by an earlier method
C-1’), 102.20 (C-3’’), 107.93 (C-5’’), 114.11 (C-2), 114.51
C-1’’), 118.46 (C-9’’), 120.85 (C-7’), 121.81 (C-6’), 123.30
C-5’), 125.63 (C-3’), 132.46 (C-6’’), 165.89 (C-2’’), 134.43
C-2’), 133.47 (C-8’’), 138.14 (C-8’), 139.90 (C-3), 164.43
C-4’’), 192.08 (C-1); ESI-MS, MeOH (Positive): m/z 320
(Black., et al 1992).
Trans-3-(1H-indol-3-yl)-1-(3’-allyloxyphenyl)-2-
propen-1-one (1h)
+
-
3
M+H] , Negative: 318[M-H] , C20H17NO .
Light brown powder; 65% yield; mp 90-92°C;IR νmax
(KBr): 3389 1564, 1211, 739 (NH), 1653 (chalcone C=O),
Synthesis of indolyl chalcones 2(a–k)

2
34
Bangladesh J Pharmacol 2015; 10: 230-240
Further, the reaction of 3-acetylindole
appropriate aldehyde 7 in presence of SOCl
the formation of indolyl chalcones 2a-k (Scheme 2)
Prince et al., 2009). Acetophenones (4h-4j) for the
6
with
Creamish powder;70% yield; mp 163-164°C; IR νmax
2
resulted in
(KBr): 3431 1586, 1201, 754 (NH), 1640 (chalcone C=O),
-1 1
1525, 1493, 1414 (aromatics) cm ; H NMR (300 MHz,
DMSO-d ): δ 3.67 (3H, s, OCH ), 3.76 (6H, s, 2 x OCH ),
(
6
3
3
preparation of the compounds 1h-1j were prepared by
etherification of o-hydroxy (3h), p- hydroxy (3i) and o,p
6.71 (1H, d, J=9.0 Hz, H-5’), 7.12 (2H, m, H-5’’, H-6’’),
7.40 (1H, d, J=6.6 Hz, H-4’’), 7.60 (1H, d, J=15.6 Hz, H-
2), 7.66 (1H, d, J=9.0 Hz, H-6’), 7.74 (1H, d, J=15.56 Hz,
H-3), 8.25 (1H, d, J=6.6 Hz, H-7’’), 8.57 (1H, brs, H-2’’),
-hydroxy (3j) acetophenones respectively with allyl
bromide in the presence of KBr in acetone using
refluxing condition.
1
3
11.79 (1H, brs, NH); C NMR (75 MHz, DMSO-d
6
): δ
), 109.28 (C-5’), 113.02 (C-4’’),
18.64 (C-1’’), 122.63 (C-6’’, C-7’’), 122.45 (C-1’), 123.41
5
6.87, 61.32, 62.3 (3 x OCH
3
The contents of reaction mixture were poured into ice-
cold water. The solid so obtained was filtered, dried
and recrystallized from ethanol to afford pure 2(a–k).
1
(
(
C-6’), 123.91 (C-5’’), 124.01 (C-2), 126.80 (C-3’’), 134.66
C-3), 135.18 (C-2’’), 137.71 (C-8’’), 142.72 (C-3’), 153.55
Trans-1-indolyl-3-(anthracenyl)-2-propen-1-one (2a)
Yellow powder; 70% yield; mp 190-191°C, IR νmax(KBr):
(C-2’), 155.85 (C-4’), 184.70 (C-1); ESI-MS, MeOH
+
+
(Positive): m/z 338 [M+H] , Negative: 336[M-H] ,
20 4
C H19NO .
3
1
398, 1570, 1234, 728 (NH), 1639 (chalcone C=O), 1518,
-1
1
442, 1419, 1381 (aromatics) cm ; H NMR (300 MHz,
): δ 6.90 (4H, m, H-5’, H-5’’, H-6’’, H-11’),
.83(2H, m, H-4’, H-12’), 6.95 (2H, m, H-3’, H-13’), 7.16
1H, d, J=15.6 Hz, H-2), 7.53 (1H, d, J=7.8 Hz, H-4’’),
Trans-1-indolyl-3-(3'-ethoxy-4-hydroxyphenyl)-2-
propen-1-one (2e)
pyridine-d
6
(
5
Light brown crystals;70% yield; mp 154-155°C; IR νmax
(
KBr): 3535 1557, 1204, 746 (NH), 3394 (OH), 1641
7
8
.83 (2H, d, J=8.1 Hz, H-6’, H-10’), 7.96 (1H, brs, H-8’),
.07 (1H, brs, H-2’’), 8.45 (1H, d, J=15.56 Hz, H-3), 8.63
-1 1
(
chalcone C=O), 1512, 1479, 1403 (aromatics) cm ; H
): δ 1.17 (3H, t, J=6.9 Hz,
), 3.99 (2H, q, J=6.9 Hz, OCH -), 7.35 (1H, d, J=8.1
Hz, H-5’), 7.39 (1H, d, J=8.1 Hz, H-6’), 7.47 (2H, m, H-
’’, H-6’’), 7.55 (1H, d, J=1.5 Hz, H-2’), 7.67 (1H, d, J=7.5
NMR (300 MHz, DMSO-d
CH
6
1
3
(
(
1H, d, J=7.8 Hz, H-7’’), 12.81 (1H, brs, NH); C NMR
75 MHz, pyridine-d ): δ 113.08 (C-4’’), 119.2 (C-1’’),
23.02 (C-6’’, C-7’’), 123.32 (C-5’’), 124.23 (C-4’, C-12’),
3
2
5
1
1
1
2
1
5
26.04 (C-5’, C-11’), 126.10 (C-6’, C-10’), 126.81 (C-3’, C-
3’), 127.49 (C-3’’), 128.34 (C-8’), 130.19 (C-1’), 131.67 (C-
’, C-14’), 132.01 (C-7’, C-9’), 134.39 (C-2), 137.57 (C-3),
Hz, H-4’’), 7.85 (1H, d, J=3.0 Hz, H-2’’), 8.06 (1H, d,
J=15.3 Hz, H-2), 8.35 (1H, d, J=15.3 Hz, H-3), 9.21 (1H,
1
3
d, J=7.8 Hz, H-7’’), 13.23 (1H, brs, NH); C NMR (75
MHz, DMSO-d ): δ 16.07 (CH ), 65.89 (OCH -), 113.90
C-4’’), 114.33 (C-2’, C-14’), 118.24 (C-5’, C-11’), 120.84
C-1’’), 123.47 (C-2), 123.76 (C-6’’), 124.59 (C-7’’), 124.77
35.04 (C-2’’), 138.47 (C-8’’), 184.37 (C-1); ESI-MS,
+
6
3
2
MeOH (Positive): m/z 348 [M+H]+, 370 [M+Na] ,
(
(
25
C H17NO.
Trans-1-indolyl-3-(2',4’-dimethoxyphenyl)-2-propen-1-
one (2b)
(C-5’’), 125.02 (C-6’, C-10’), 128.78 (C-3’’), 129.10 (C-1’),
135.34 (C-2’’), 139.48 (C-8’’), 142.96 (C-3), 149.57 (C-3’, C
-
(
13’), 152.04 (C-4’, C-12), 186.47 (C-1); ESI-MS, MeOH
Positive): m/z 308 [M+H] , Negative: 306[M-H] ,
Creamish white crystals, 10% yield, obtained and
analysed by spectroscopic data as described by an
earlier method (Yesuthangan et al., 2011).
+
+
19 3
C H17NO .
Trans-1-indolyl-3-(3',5’-dimethoxy-4’-hydroxyphenyl)-
-propen-1-one (2f)
Trans-1-indolyl-3-(3',4’,5’-trimethoxyphenyl)-2-propen
2
-1-one (2c)
Creamy crystals;70% yield; mp 210-211°C; IR νmax(KBr):
445, 1580, 1191, 740 (NH), 3445 (OH), 1640 (chalcone
C=O), 1522, 1491, 1404 (aromatics) cm ; H NMR (300
Light orange crystals;70% yield; mp 191-192°C; IR νmax
3
(
KBr): 3448 1581, 1197, 755 (NH), 1642 (chalcone C=O),
-1 1
-1 1
1
515, 1459, 1426 (aromatics) cm ; H NMR (300 MHz,
): δ 3.86 (3H, s, OCH ), 3.71 (6H, s, 2 x OCH ),
.18 (2H, brs, H-2’, H-6’), 7.24 (2H, m, H-5’’, H-6’’), 7.51
1H, dd, J=6.3, 2.1 Hz, H-4’’), 7.62 (1H, d, J=15.6 Hz, H-
), 7.78 (1H, d, J=15.6 Hz, H-3), 8.38 (1H, dd, J=6.3, 2.1
Hz, H-7’’), 8.75 (1H, d, J=3 Hz, H-2’’), 12.12 (1H, brs,
1
MHz, DMSO-d
3
6
): δ H NMR (300 MHz, DMSO-d
6
): δ
), 6.49 (2H, br s, H-2’), 6.61 (2H,
m, H-5’’, H-6’’), 6.90 (1H, dd, J=6.9, 1.5 Hz, H-4’’), 6.99
DMSO-d
7
(
2
6
3
3
.51 (6H, brs, 2x OCH
3
(
(
1H, d, J=15.3Hz, H-2), 7.04 (1H, d, J=15.3 Hz, H-3), 7.70
1H, dd, J=8.1, 1.8 Hz, H-7’’), 8.06 (1H, d, J=2.7 Hz, H-
1
3
1
3
2’’), 11.43 (1H, brs, NH); C NMR (75 MHz, DMSO-d
6
):
NH); C NMR (75 MHz, DMSO-d
0.99 (OCH ), 106.92 (C-2’, C-6’), 113.04 (C-4’’), 118.68
C-1’’), 122.70 (C-6’’, C-7’’), 123.97 (C-5’’), 124.77 (C-3),
6 3
): δ 56.97 (2 x OCH ),
δ 57.01 (2 x OCH ), 107.03 (C-2’, C-6’), 113.08 (C-4’’),
3
6
(
3
1
1
2
18.56 (C-1’’), 122.47 (C-2), 122.61 (C-7’’), 122.81 (C-6’’),
24.08 (C-5’’), 126.42 (C-1’), 126.64 (C-3’’), 135.29 (C-
’’),137.67 (C-8’’), 138.62 (C-4’), 141.83 (C-3), 148.90 (C-
1
1
1
26.81 (C-3’’), 131.69 (C-1’), 135.52 (C-2’’), 137.79 (C-8’’),
40.07 (C-4’), 140.84 (C-2), 154.01 (C-3’, C-5’), 184.54 (C-
); ESI-MS, MeOH (Positive): m/z 338 [M+H] ,
+
3’, C-5’), 185.13 (C-1); ESI-MS (Positive): m/z 324
+
-
[
4
M+H] , Negative: 322 [M-H] , C19H17NO .
20 4
C H19NO .
T r a n s - 1 - i n d o l y l - 3 - ( 3 ' , 5 ’ - d i m e t h o x y - 4 ’ -
benzyloxyphenyl)-2-propen-1-one (2g)
Trans-1-indolyl-3-(2'3',4’-trimethoxyphenyl)-2-propen-
-one(2d)
1

Bangladesh J Pharmacol 2015; 10: 230-240
Creamish crystals;70% yield; mp 209-210°C; IR νmax
11NOS.
235
15
C H
(
1
KBr): 3440 1576, 1203, 739 (NH), 1655 (chalcone C=O),
Trans-1-indolyl-3-(benzodioxanyl)-2-propen-1-one (2k)
-1 1
742(ester CO), 1512, 1466, 1426 (aromatics) cm ; H
): δ 7.24 (1H, dd, J=7.5, 1.5
NMR (300 MHz, DMSO-d
6
Light orange,90% yield; mp 154-155°C; IR νmax(KBr):
Hz, H-10’), 7.31 (2H, d, J=7.5 Hz, H-3’, H-6’), 7.54 (2H,
dd, J=8.4, 2.7 Hz, H-9’, H-11’), 7.58 (2H, m, H-5’’, H-6’’),
3449 1580, 1251, 752 (NH), 1638 (chalcone C=O), 1509,
1439, 1291 (aromatics) cm-1
1
;
H NMR (300 MHz, DMSO-
7
(
3
.68 (1H, d, J=15.3 Hz, H-2), 8.70 (1H, br s, H-2’’), 7.72
1H, dd, J=7.2, 1.2 Hz, H-4’’), 7.88 (1H, d, J=15.3 Hz, H-
), 8.12 (2H, d, J=7.5 Hz, H-8’, H-12’), 8.38 (1H, dd,
d ): δ 4.25 (2H, s, H-5’, H-6’), 6.88 (1H, d, J=8.4 Hz, H-
6
3’), 7.21 (2H, m, H-5’’, H-6’’), 7.28 (1H, dd, J=8.4, 1.5 Hz,
H-2’), 7.42 (1H, d, J=1.5 Hz, H-8’), 7.48 (1H, dd, J=6.6,
2.7 Hz, H-4’’), 7.52 (1H, d, J=15.3 Hz, H-2), 7.66 (1H, d,
J=15.6 Hz, H-3), 8.33 (1H, dd, J=6.3, 2.4 Hz, H-7’’), 8.68
(1H, brs, H-2’’), 12.04 (1H, brs, NH);13C NMR (75 MHz,
1
3
J=6.6, 2.1 Hz, H-7’’), 12.20 (1H, brs, NH); C NMR (75
MHz, DMSO-d ): δ 106.79 (C-2’, C-6’), 113.12 (C-4’’),
18.67 (C-1’’), 122.77 (C-6’’, C-7’’), 123.23 (C-5’’), 125.90
C-2), 126.79 (C-3’’), 129.32 (C-1’), 129.90 (C-9’, C-11’),
30.85 (C-8’, C-12’), 134.96 (C-10’), 135.77 (C-2’’), 137.83
6
1
(
1
DMSO-d ): δ 64.86* (C-4’), 65.21* (C-5’), 122.66 (C-6’’, C-
6
7’’), 123.26 (C-8’), 123.70 (C-2), 123.94 (C-5’’), 126.76 (C-
3’’), 129.56 (C-1’), 135.34 (C-2’’), 137.71 (C-8’’), 140.28 (C-
3), 144.45 (C-6’), 145.97 (C-3’), 184.69 (C-1)
(*=interchangable);ESI-MS, MeOH (Positive): m/z 306
(
(
[
C-8’’), 140.43 (C-3), 153.02 (C-3’, C-4’, C-5’), 164.48
CO), 184.42 (C-1); ESI-MS, MeOH (Positive): m/z 428
M-H] , 450 [M+Na] , Negative: 428[M-H] , C26H21NO .
5
+
+
-
+
-
[
3
M+H] , Negative: 304 [M-H] , C19H15NO .
Trans-1-indolyl-3-(4'-hydroxyphenyl)-2-propen-1-one
2h)
(
Molecular modelling parameters and energy
minimization
Dark brown powder,85% yield, obtained and analysed
by spectroscopic data as described by an earlier method
To find the possible interactions of indolyl chalcones
analogues compounds 1b, 1f and 1g with colon cancer
target cyclin-dependent kinase2 (CDK2), we docked
compounds at CDK2 binding site. Sybyl X 2.0 inter-
faced with Surflex–Dock module was used for mole-
cular docking. Program automatically docks ligand into
binding pocket of a target protein using protomol based
algorithm and empirically produced scoring function.
The X-ray crystallographic structures of CDK2 complex
with ligand (PDB ID: 2R3J) (Yoon et al., 2013) was taken
from the protein data bank and water molecules were
removed, H atoms were added and side chains were
fixed. Protein structure minimization was performed by
applying Tripos force field and partial atomic charges
were calculated by Gasteiger-Huckel method. In
reasonable binding pocket, all the compounds were
docked into the binding pocket and 20 possible active
docking conformations with different scores were
obtained for each compound. During the docking
process, all of the other parameters were assigned their
default values (Yadav et al., 2014).
(
Kumar., et al 2010).
Trans-1-indolyl-3-(2'-methylphenyl)-2-propen-1-one
(
2i)
Obtained as brown solid; 80% yield; mp 140-142ºC; IR
ν
max
(KBr): 3422, 1562, 1156, 748 (NH), 1639 (chalcone
-1 1
C=O), 1520, 1442, 1492 (aromatics) cm ; H NMR (300
MHz, DMSO-d ):δ 2.34(3H, s, CH ), 7.13-7.18 (5H, m, H-
', H-4', H-5', H-5'', H-6''), 7.40 (1H, dd, J=8.1 Hz, 2.1 Hz,
6
3
3
H-4''), 7.63 (1H, d, J=15.6 Hz, H-2), 7.82 (1H, d, J=15.6
Hz, H-3), 7.87 (1H, dd, J=7.5, 2.4 Hz, H-6'), 8.25 (1H, dd,
J=6.6, 2.1Hz, H-7''), 8.63 (1H, d, J=3.0 Hz, 1H, H-2''),
1
2
1
1
1
1
13
2.05 (1H, brs, NH); CNMR (75 MHz, DMSO-d
6
): δ
0.23 (CH ), 113.07 (C-4''), 118.54 (C-1''), 122.61 (C-7''),
3
22.74 (C-6''), 123.99 (C-5''), 126.36 (C-2), 126.80 (C-3''),
27.11 (C-5'), 127.36 (C-6' ), 130.41 (C-4'), 131.55 (C-3'),
34.68 (C-1'), 135.63 (C-2''), 137.54 (C-3), 137.76 (C-8''),
38.23 (C-2'), 184.55 (C-1); ESI-MS, MeOH (Positive):
+
-
m/z 262 [M+H]+, 284 [M+Na] , Negative: 260 [M-H] ,
C H15NO.
18
Trans-1-indolyl-3-(thiophenyl)-2-propen-1-one (2j)
Screening through pharmacokinetic properties
Creamish white powder;70% yield; mp 181-182°C; IR
During the process of drug discovery, most of drugs fail
to cross the clinical trials because of poor
pharmacokinetic properties (absorption, Distribution,
metabolism, excre-tion, and toxicity) (Yadav et al.,
2013). Some properties correlate well e.g., primary
determinant of fractional absorption referred to as polar
max
ν
(KBr): 3448 1578, 1199, 754 (NH), 1632 (chalcone
-1 1
C=O), 1523, 1493, 1438, 1315 (aromatics) cm ; H NMR
300 MHz, DMSO-d ): δ 6.03 (1H, d, J=4.2 Hz, H-2’),
.10 (2H, m, H-5’’, H-6’’), 6.34 (1H, m, H-4’’), 6.36 (1H,
(
6
6
d, J=15.3 Hz, H-2), 6.45 (1H, brs, H-4’), 6.55 (1H, d, J=4.2
Hz, H-3’), 6.66 (1H, d, J=15.3 Hz, H-3), 7.50 (1H, d, J=7.5
2
surface area (PSA) (cut-off ≤ 140Å ) and low molecular
13
Hz, H-7’’), 7.52 (1H, brs, H-2’’), 10.95 (1H, brs, NH); C
NMR (75 MHz, DMSO-d ): δ 113.06 (C-4’’), 118.34 (C-
’’), 122.62 (C-7’’), 122.72 (C-6’’), 124.00 (C-5’’), 124.07 (C
2), 126.71 (C-3’’), 129.32 (C-2’), 129.76 (C-3’), 132.06 (C-
weight for absorption). The compound distribution in
the body depends on factors such as blood–brain
barrier, permeability, the volume of distribution and
plasma protein binding. The descriptors’ values of 90%
orally active compounds follows Lipinski’s rule. The
bioavailability of com-pounds was evaluated by
topological polar surface area value. This descriptor
6
1
-
4
1
’), 133.32 (C-3), 135.40 (C-2’’), 137.73 (C-8’’), 141.06 (C-
’), 184.03 (C-1); ESI-MS, MeOH (Positive): m/z 254
+
+
-
[M+H] , 276 [M+Na] , Negative: 252 [M-H] ,

2
36
Bangladesh J Pharmacol 2015; 10: 230-240
correlates well with passive molecular transport
through membranes. The number of rotatable bonds is
a topological parameter as a measure of molecular
flexibility (cut-off ≤10) and oral bioavailability (Bhagat
et al., 2013).
Chalcone 1b bearing benzofuran ring is most active in
this series and selectively cytotoxic against colon cancer
cell lines (Caco-2) with an IC50 value of 7.4 µg/mL
whereas compound 1f bearing benzyloxy group in the
aromatic ring is as active as 1g, IC50 7.8 µg/mL against
Caco-2 cancer cell line. Compound 1g with o-hydroxy
group is moderately cytotoxic against all the caco2 cell
lines without any selectivity. Introduction of m-allylic
group in the aryl ring i.e. compound 1h is beneficial for
the activity as compared to compound 1g.
MTT anti-proliferative activity assay
In vitro anti-cancer activity of phytomolecules is done
by using MTT assay. Cytotoxicity testing in vitro was
4
done by the method of Woerdenbag et al. 1-2 x 10
cells/well were incubated in the 5% CO
2
incubator for
In other series, Compound 2i has displayed significant
cytotoxicity against Caco-2 with an IC50 value of 7.4 µg/
mL. Indolyl chalcone 2c with a 3,4,5-trimethoxy substi-
tuent and 2i with 3-ethoxy-4-hydroxy substituent were
moderately active and selective against caco-2 with an
IC50 value of 7.4 µg/mL (Table II).
2
4 hours to enable them to adhere properly to the 96-
well polystyrene microplate (Grenier, Germany). Test
compounds dissolved in 100% DMSO (Merck,
Germany) in at least five doses was added and left for 6
hours after which the compounds plus media was
replaced with fresh media and the cells were incubated
for another 48 hours in the CO
2
incubator at 37⁰C. The
In the study, we explored the orientations and binding
affinities (in terms of total score). The docking reliability
was validated by using the known crystallized X-ray
concentration of DMSO used in our experiments never
exceeded 1.25%, which was found to be non-toxic to
cells. Then, 10 µL MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium bromide; Sigma M 2128] was
added, and plates were incubated at 37⁰C for 4 hours.
One hundred microlitres of dimethyl sulfoxide (DMSO,
Merck, Germany) was added to all wells and mixed
thoroughly to dissolve the dark blue crystals. After a
few min at room temperature to ensure that all crystals
Table I
In vitro cytotoxicity data of indolyl chalcones (1a–j)
Compounds
R
Caco-2 IC50 (µg/mL)
96
1
1
a
CH3
were dissolved, the plates were read on
a
F
spectrofluorometer FLUO star Omega (BMG Labtech)
at 570 nm. Plates were normally read within 1 hour of
adding the DMSO. The experiment was done in
triplicate and the inhibitory concentration (IC) values
were calculated as follows:
b
7.4
O
1
c
100
%
inhibition = (1-OD at 570 nm of sample well/OD at
5
70 nm of control well) x 100
1
d
52
NO
7.8
IC50 is the concentration mg/mL required for 50%
inhibition of cell growth as compared to that of
untreated control.
O
1
e
Cl
1
f
Cl
Results and Discussion
Chalcones are a major class of natural products and are
considered as the precursors of flavonoids and isoflavo-
noids. Chemically, chalcones are 1,3-diaryl-2-propen-1-
ones in which two aromatic rings are joined by a three
carbon bridge having a carbonyl moiety and ꢀ,ꢁ
unsaturation (Aggarwal et al., 2005). In this study both
series of indolyl chalcones found in good yields, which
are in line with aforementioned references. All these
indolyl chalcones were assayed for their in vitro cyto-
toxicity against human colon (Caco-2) cancer cell lines.
The IC50 values were used to determine the growth
inhibition of these cancer cell lines. From the IC50 values
summarized in Table I, the compounds 1b, 1f and 1g
have shown significant cytotoxicity. Furan moieties are
common sub-structures in numerous natural products.
1
g
h
HO
7.8
1
8.7
O
1i
O
CH2
NO
1j
HO
O
NO
3.5
Doxorubicin
Caco-2 = colon cancer; Doxorubicin (SigmaD-1515) is the standard used

Bangladesh J Pharmacol 2015; 10: 230-240
237
almost in the same position with co-crystallized at the
active site of paclitaxel. Crystallography data CDK2
showed that the amino acid Asp-86 is the "gatekeeper"
residue, an important determinant of inhibiting in the
CDK2 binding pocket.
Table II
In vitro cytotoxicity data of indolyl chalcones (2a–k)
Compounds
R
Caco-2 IC50 (µg/mL)
NO
The docking results as shown for compounds 1b, 1f and
2
a
1
g was docked at CDK2 binding pocket as shown
docking score in the form of total score was i.e. 7.1740,
.9001 and 6.3035 respectively. While, the docking
5
scores of doxorubicin were 4.6772 only. The docked
view of compounds 1b and 1g shows the formation of a
hydrogen bond of length 2.0, 1.8 and 1.8Å to the polar
hydrophobic residue Asp-86, Asp-145 and Asn-132. In
docking pose, the conserved binding site pocket of
amino acid residues within a selection radius of 3Å
from bound ligand were hydrophobic residue Val-18
2
b
CH3
O
NO
74
O
CH3
2
c
CH3
O
O
CH3
O
(
1
(
valine), Phe-80, Phe-82 (phenylalanine), Asp-86, Asp-
45 (aspartic acid), HIS-390 (histidine), Leu-83, Leu-134,
leucine), Ala-31, Ala-144 (alanine), Ile-10 (isoleucine),
CH3
CH3
2
d
NO
88
CH3
O
O
O
CH3
nucleophilic (polar, hydrophobic), i.e. Thr-14 (threo-
nine) and polar amide, e.g. Gln-85, Gln-131 (glutamine)
as a result as shown in Table III, bind compound
showed a high interaction compare to with doxorubicin
show more stability and activity in this compound.
Overall, docking studies clearly indicates that com-
pound 1b and 1g binds well (Figure 3) with CDK2
binding site and hence may exhibit similar inhibition
effects on colon cancer receptor CDK2. These results
were further substantiated by wet lab experiments.
2
e
CH3
O
OH
2
f
CH3
NO
32
O
OH
O
CH3
2
g
h
CH3
O
In our study, the ADME (absorption, distribution,
metabolism and excretion) parameters were calculated
for the active chalcone derivatives namely, compounds
O
C6H5
O
O
CH3
1
b, 1f and 1g. The values of these parameters also
2
OH
NO
7.4
showed close correspondence with those of control
compound doxorubicin and were within the standard
range of values exhibited by 95% of all known drugs.
Typically, low solubility is associated with bad absor-
ption, so the general aim is to avoid poorly soluble
compounds. The aqueous solubility (logS) of a com-
pound significantly affects its absorption and distribu-
tion characteristics. The calculated logS values of the
studied compounds were within the acceptable inter-
val. Other calculations related to solubility, serum pro-
tein binding, the blood–brain barrier (log BB and appa-
rent MDCK cell permeability), gut–blood barrier (Caco-
2
i
H C
3
2
j
NO
NO
3.5
H C
3
S
O
2
k
O
Doxorubicin
Caco-2 = colon cancer; Doxorubicin (SigmaD-1515) is the standard used
2
cell permeability), predicted central nervous system
structure of target protein LRH-1 complex with 3-
bromo-5-phenyl-N-(pyridin-3-ylmethyl) pyrazolo [1,5-
a]pyrimidin-7-amine. The co-crystallized structure was
re-docked into the binding site and the docked
conformation with the highest total score of 6.54 was
selected as the most probable binding conformation.
The low root mean-square deviation (RMSD) of 0.56 Å
between the docked and the crystal conformations
indicates the high reliability of Surflex-dock software in
reproducing the experimentally observed binding
mode for doxorubicin. Redocked molecules were
activity, number of likely metabolic reactions, log IC50
for hERG K+ channel blockage, skin permeability (Kp),
and human oral absorption in the gastrointestinal tract
showed that these values for the active chalocone
derivatives fell within the standard ranges generally
observed for drugs (Table IV).
Toxicity screening results showed that compounds 1b,
1
f and 1g possess risk of mutagenicity toxicity, however
indicate significant docking and experimental based
anti-cancer activity (Table V). Thus, there is a need for

2
38
Bangladesh J Pharmacol 2015; 10: 230-240
Table III
Comparison of binding affinity of standard drug (control) anti-cancer drugs and active chalcone derivative
against colon cancer receptor (PDB ID:2R3J)
Compound
name
Total
score
Amino acid involved in
active pocket in 3Å
Involved group
of amino acid
Length of
H-bond Ă
Number of Hy-
drogen Bond
1
b
7.2
Ile-10, Gly-11, Glu-12, Gly-13, Val-18, Ala-31,
Phe-80, Phe-82, Leu-83, His-84, Gln-85, Asp-86,
Lys-89, Lys-129, Gln-131, Asn-132, Leu-134, Ala-
Asp-86
2.0
1
1
44
1
1
f
5.9
6.3
Ile-10, Val-18, Ala-31, Lys-33, Val-64, Phe-80, Glu
-
-
-
-81, Phe-82, Leu-83, His-84, Leu-134, Ala-144,
Asp-145
g
Ile-10, Glu-12, Gly-13, Thr-14, Val-18, Ala-31,
Lys-33, Val-64, Phe-80, Glu-81, Phe-82, Leu-83,
Lys-129, Asn-132, Leu-134, Ala-144, Asp-145
Asp-145
Asn-132
1.8
1.8
2
Doxorubicin
4.7
Ile-10, Val-18, Ala-31, Lys-33, Val-64, Phe-80, Phe
Lys-89
Asp-86
Leu-83
2.0
1.9
2.1
3
-82, Leu-83, His-84, Gln-85, Asp-86, Lys-88, Lys-
8
9, Gln-131, Leu-134, Ala-144
Surflex-Dock scores (total scores) were expressed in –log10(Kd) units to represent binding affinities
Figure 3: In silico molecular docking studies elucidating the possible mechanisms of compound 1b and 1g induced modulation of
colon cancer protein (CDK2) receptor (PDB: 2R3J). The docking studies were carried out using SYBYL-X 2.0, Tripos International.
Compound 1b and 1g docked on CDK2 form a H-bond of length 2.0 and 1.8Å to the binding pocket residue Asp-86, Asp-145 and
Asn-132 and total score 7.1740 (A) and 6.3035 (B) was observed
more qualitative safety evaluation of chalcone. This is
particularly important because of the fact that chalcone
derivatives are used very frequently in clinical and non-
clinical settings. The compliance of active chalcone
derivatives namely, compounds 1b, 1f and 1g with
computational toxicity risks parameters indicate that
these compounds are active and safe except mutageni-
city toxicity risk at high doses or long term use similar
to standard anti-cancer drugs namely doxorubicin.
Therefore lead optimization of these active chalcone
derivatives is a subject of further research work. Results
of ADMET revealed that the overall drug scores of
predicted active compounds are comparable to that of
standard drugs and also established through in vitro
experimental data (Table I) tested in colon (Caco-2)
cancer cell line.
the management of colon cancer.
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Table V
Compliance of active indolyl chalcones to computational toxicity risks
parameters (i.e., mutagenicity, tumorogenicity, irritation and reproduction)
Compounds
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TUMO
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No risk
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Author Info
Guo-Dong Huang (Principal contact)
e-mail: dongguo772@gmail.com

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