Synthesis and biological evaluation of indolyl chalcones as antitumor agents

Article abstract of DOI:10.1016/j.bmcl.2010.05.016

A series of indolyl chalcones were synthesized and evaluated in vitro for their anticancer activity against three human cancer cell lines. Compounds 3b-d, 3h, 3j, 3l, 3m, 4g, and 4j showed significant cytotoxicity, particularly, indolyl chalcones 3l and 3

Full text of DOI:10.1016/j.bmcl.2010.05.016

Bioorganic & Medicinal Chemistry Letters 20 (2010) 3916–3919
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and biological evaluation of indolyl chalcones as antitumor agents
a
b
b
c
b,
Dalip Kumar a, , N. Maruthi Kumar , Kanako Akamatsu , Eriko Kusaka , Hiroshi Harada , Takeo Ito
*
*
a Birla Institute of Technology and Science, Pilani 333 031, India
b Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
c Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of indolyl chalcones were synthesized and evaluated in vitro for their anticancer activity against
three human cancer cell lines. Compounds 3b–d, 3h, 3j, 3l, 3m, 4g, and 4j showed significant cytotoxicity,
particularly, indolyl chalcones 3l and 3m were identified as the most potent and selective anticancer
Received 18 December 2009
Revised 2 March 2010
Accepted 8 May 2010
Available online 13 May 2010
agents with IC50 values 0.03 and 0.09
lM, against PaCa-2 cell line, respectively.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Indolyl chalcones
Anticancer agents
1,3-Diaryl-2-propen-1-ones
Chalcones (1,3-diaryl-2-propen-1-ones) with an enone system
between two aromatic rings constitute an important class of natural
products which serve as precursors for the preparation of various
flavonoids and exhibitinteresting pharmacological activities.1,2 Nat-
ural and synthetic chalcones have shown broad spectrum of biolog-
ical activities such as antiinflammatory,3 antituberculosis,4
antifungal,5 antimalarial,6 antileish-manicidal,7 and anticancer.8–12
Recent development of anticancer agents involve structural modifi-
cation of chalcones to improve their bioavailability and to study the
role of various substituents on aryl or heteroaryl rings.13 Chalcones,
potential.3b,6,22 In continuation of our efforts to design indole-based
novel and selective antitumor agents, we report herein the synthe-
sis and anticancer activity of indolyl chalcones 3 and 4.
In the present study we have synthesized two different series of
indolyl chalcones 3 and 4 with various structural modifications.
N
N
N
O
2
R1
O
1
R1
O
in which both the 1,3-diaryl rings are separated by three-carbon a,b-
N
R
N
R
unsaturated carbonyl system, are structurally similar to indolyl het-
erocycles 1 (Fig. 1) having 2,5-diaryl rings separated by three atoms
and connected to each other via a five-membered heterocyclic unit.
A large number of 5-(30-indolyl)azoles isolated from different
microorganisms are reported to display interesting biological activ-
ities.14–16 The natural bis(indole) alkaloids such as topsentin and
nortopsentins have demonstrated significant in vitro cytotoxicity
against P388 cells.17 Recently, we have reported indolyl-1,3,4-oxa-
diazoles 2 as potent anticancer agents.18 There are many indole-
based compounds found to be effective as tubulin assembly inhib-
itors such as recently reported 3-arylthioindoles which induce sig-
nificant cellular apoptosis.19 In the recent past, many diarylazoles
are reported as analogs of chalcones with reduced activity. Replace-
ment of a five-membered heterocyclic ring with an enone moiety
has been proven to be beneficial for the biological activity.20,21 In-
dole-based chalcones are largely unexplored for their anticancer
O
R1
R1
N
R
N
R
4
3
Figure 1.
O
CHO
+
R1
R1COCH3
N
R
N
R
5a
3a-f & l
3g-k & m
R= H
R= CH3
R= H
6
5b R= CH3
* Corresponding authors. Tel.: +91 1596 245073 279; fax: +91 1596 244183.
E-mail addresses: dalipk@bits-pilani.ac.in (D. Kumar), takeoit@scl.kyoto-u.ac.jp
(T. Ito).
Scheme 1. Reagents and conditions: piperidine, ethanol, reflux, 80 °C, 20 h.
0960-894X/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2010.05.016

D. Kumar et al. / Bioorg. Med. Chem. Lett. 20 (2010) 3916–3919
3917
prostatic adenocarcinoma (PC-3).28 The IC50 values were used to
determine the growth inhibition in the presence of indolyl chal-
cones 3 and 4 against A-549, PaCa-2 and PC-3 cancer cell lines.
From the IC50 values summarized in Table 1, the compounds 3 have
shown significant cytotoxicity, especially 3c, 3l, and 3m.
O
COCH3
+ R1CHO
R1
N
R
N
R
The compound 3b with p-methoxy group is moderately cyto-
toxic against all the three cell lines without any selectivity. Intro-
duction of second methoxy group in the aryl ring is beneficial for
the activity (compound 3c vs compound 3b). The compound 3c
exhibited improved cytotoxicity against all the cancer cell lines
when compared to the compound 3b. However, replacement of
3,4-dimethoxy groups with methylenedioxy moiety led to the
compound 3d with reduced activity. Further, compounds 3l and
3m bearing 3,4,5-trimethoxy groups in the aromatic ring are most
active in this series, the compound 3l is selectively cytotoxic
4a-g
4h-j
R= H
R= H
8
7a
7b R= CH3
R= CH3
Scheme 2. Reagents and conditions: NaOH, ethanol, reflux 80 °C, 15 h.
General methods for the preparation of chalcones involve Claisen–
Schmidt condensation of appropriate aryl methyl ketones and
aldehydes in presence of acid or base.23 The chalcones 3 were pre-
pared by the reaction of indol-3-carboxaldehyde 5 with appropri-
ate acetophenone 6 in presence of piperidine under refluxing
conditions (Scheme 1).23–25 However, under similar reaction condi-
tions, synthesis of compounds 4 was unsuccessful. Further, the
reaction of 3-acetylindole 7 with appropriate aldehyde 8 in pres-
ence of dilute sodium hydroxide under refluxing condition resulted
in the formation of chalcones 4 in good yield (Scheme 2).26,27 Since
we were successful in our initial efforts to prepare both types of
chalcones (3, 4) using aforementioned conditions in good yields,
further reaction conditions were not optimized.
against PaCa-2 cancer cell line with an IC50 value of 0.03
N-methylation of indole ring nitrogen led to the compound 3m
with reduced activity (IC50 = 0.09 M) against PaCa-2 cancer cell
lM. The
l
line. In other series, compounds 4g and 4j have shown good activ-
ity against A-549 and PaCa-2 cancer cell lines (Table 2). Compound
4g has displayed significant cytotoxicity against PaCa-2 with an
IC50 values 4.4
tuent at para position was moderately active and selective against
A-549 with an IC50 value of 8.7 M.
lM. Indolyl chalcone 4j with a N,N-dimethyl substi-
l
Indolyl chalcones 3 and 4 were assayed for their in vitro cyto-
toxicity against three human cancer cell lines: epithelial (A-549),
pancreatic carcinoma (PaCa-2) and androgen-independent human
In summary, we have prepared two series of indolyl chalcones
that inhibit the growth of A-549, PaCa-2, and PC-3 cancer cell lines
at micromolar concentration. Compounds 3c, 3h, 3l, and 3m were
Table 1
In vitro cytotoxicity data of indolyl chalcones (3a–m)
Compound
R
R1
Anticancer activity (IC50
PaCa-2
l
M)a
A-549
PC-3
24 h
48 h
24 h
48 h
ND
46.5
4.5
7.9
ND
24 h
48 h
3a
3b
3c
3d
3e
3f
H
H
H
H
H
H
4-OHC6H4
ND
58.2
9.5
15.2
ND
ND
41.5
4.9
10.8
ND
>100
48.0
7.6
15.1
ND
ND
ND
50.6
>100
ND
ND
4-OCH3C6H4
3,4-(OCH3)2C6H3
3,4-(OCH2O)C6H3
4-FC6H4
56.2
27.9
34.2
ND
2-C5H4N
ND
ND
ND
ND
ND
ND
3g
3h
3i
3j
3k
3l
CH3
CH3
CH3
CH3
CH3
H
4-FC6H4
ND
8.5
ND
8.3
>100
8.9
56.8
24.8
83.7
ND
ND
3.9
ND
ND
>100
>100
ND
ND
3,4-(OCH3)2C6H3
4-OCH3C6H4
3,4-(OCH2O)C6H3
4-OHC6H4
3,4,5-(OCH3)3C6H2
3,4,5-(OCH3)3C6H2
34.3
66.6
>100
65.6
0.10
0.15
58.4
21.6
92.8
0.20
0.21
39.7
16.2
37.1
0.10
0.15
40.3
13.4
36.1
0.03
0.09
ND
ND
3m
CH3
0.28
ND: not detectable.
a
Data expressed in terms of IC50 values were obtained by dose dependent response.
Table 2
In vitro cytotoxicity data of indolyl chalcones (4a–j)
Compound
R
R1
Anticancer activity (IC50
PaCa-2
l
M)a
A-549
PC-3
24 h
48 h
24 h
48 h
24 h
48 h
4a
4b
4c
4d
4e
4f
4g
4h
4i
H
H
H
H
H
H
H
CH3
CH3
CH3
4-OHC6H4
—
ND
—
ND
ND
ND
12.9
—
—
ND
—
ND
ND
ND
6.0
—
—
ND
—
ND
ND
ND
7.2
—
—
ND
—
ND
ND
ND
4.4
—
—
ND
—
ND
ND
ND
19.1
—
—
ND
—
ND
ND
ND
9.0
—
4-OCH3C6H4
3,4-(OCH3)2C6H3
3,4-(OCH2O)C6H3
4-N(CH3)2C6H4
3-Indolyl
4-C5H4N
4-OCH3C6H4
3,4-(OCH3)2C6H3
4-N(CH3)2C6H4
—
19.5
—
8.7
—
17.1
—
15.0
—
ND
—
ND
4j
ND: not detectable; —: not soluble in buffer.
a
Data expressed in terms of IC50 values were obtained by dose dependent response.

3918
D. Kumar et al. / Bioorg. Med. Chem. Lett. 20 (2010) 3916–3919
Hb). 8.37 (d, 1H, J = 3.32 Hz, Ar-H), 9.92 (s, 1H, NH); IR (KBr,
m
cmꢀ1): 3275–
significantly cytotoxic against all three cancer cell lines with selec-
tivity towards PaCa-2. In other series, compounds 4g and 4j exhib-
ited good cytotoxicity. The preliminary anticancer activity study of
both the series of indolyl chalcones reveals that 3,4,5-trimethoxy-
phenyl, 4-pyridyl and N,N-dimethylphenyl moieties are beneficial
for anticancer activity and selectivity.
Further, N-methylation of indole ring nitrogen does not im-
prove the activity. Initial anticancer activity results of indolyl chal-
cones 3 and 4 have generated further interest to optimize their
activity and investigate specific biological targets of these com-
pounds at molecular level.
3197 (OH), 3178 (NH) 1658 (C@O), 1577, 1520, 1487, 972, 837. 752; (FAB) m/z
calcd for C17H13NO2 (M)+, 263.0960, obsd 263.0940. 3b: yield 70%, yellow solid,
mp 169–171 °C; 1H NMR (400 MHz, CDCl3): d 3.90 (s, 3H, OCH3), 7.01 (d, 2H,
J = 9.56 Hz, Ar-H), 7.25–7.28 (m, 2H, Ar-H), 7.46–7.50 (m, 2H, Ar-H), 7.57 (d,
1H, J = 15.44 Hz, H ), 7.65 (d, 1H, J = 2.84 Hz, Ar-H), 7.98–8.01 (m, 1H, Ar-H),
a
8.05 (d, 1H, J = 4.92 Hz), 8.09 (d, 1H, J = 15.44 Hz, Hb), 11.12 (s, 1H, NH); IR (KBr,
m
cmꢀ1): 3387 (NH), 1653 (C@O), 1600, 1585, 1523, 1448, 1261, 829, 740;
HRMS (FAB) m/z calcd for C18H15NO2 (M+H)+ 278.1136, obsd 278.1178. 3c:
yield 75%, yellow solid, mp 189–191 °C; 1H NMR (400 MHz, CDCl3): d 3.93 (s,
6H, OCH3), 6.94 (d, 1H, J = 8.56 Hz, Ar-H), 7.28 (d, 1H, J = 14.16 Hz, H ), 7.43–
a
7.59 (m, 3H, Ar-H), 7.72 (s, 1H, Ar-H), 7.84 (d, 1H, J = 8.24 Hz, Ar-H), 8.08 (d, 1H,
J = 15.36 Hz, Hb). 8.30 (d, 1H, J = 4.4 Hz, Ar-H), 8.55 (s, 1H, Ar-H), 10.08 (s, 1H,
NH); IR (KBr,
m
cmꢀ1): 3219 (NH), 1645 (C@O), 1593, 1554, 1516, 1417, 1228,
800, 740; HRMS (FAB) m/z calcd for C19H17NO3 (M+H)+ 308.1242, obsd
308.1292. 3d: yield 65%, pale yellow solid, mp 184–187 °C; 1H NMR (400 MHz,
CDCl3): d 6.08 (s, 2H, CH2), 6.93 (d, 1H, J = 8.12 Hz, Ar-H), 7.24–7.28 (m, 2H, Ar-
Acknowledgment
H), 7.48 (d, 2H, J = 9.52 Hz, Ar-H), 7.53 (d, 1H, J = 15.84 Hz, H ), 7.66–7.70 (m,
a
2H, Ar-H), 7.96–7.98 (m, 1H, Ar-H), 8.08 (d, 1H, J = 15.40 Hz, Hb). 11.24 (s, 1H,
m
cmꢀ1): 3190 (NH), 1650 (C@O), 1585, 1558, 1527, 1445, 1248,
We gratefully acknowledge the financial support of Department
of Science and Technology, New Delhi.
NH); IR (KBr,
830, 735; HRMS (FAB) m/z calcd for C18H13NO3 (M+H)+ 292.0929, obsd
292.0970. 3e: yield 70%, off-white solid, mp 185–188 °C; 1H NMR (400 MHz,
CDCl3): d 7.16–7.21 (m, 2H, Ar-H), 7.31–7.33 (m, 2H, Ar-H), 7.45–7.47 (m, 1H,
References and notes
Ar-H), 7.56 (d, 1H, J = 15.52 Hz, H ), 7.63 (d, 1H, J = 2.68 Hz), 8.01–8.03 (m, 1H,
a
Ar-H), 8.09 (d, 1H, J = 15.40 Hz, Hb). 8.10–8.13 (m, H, Ar-H), 10.24 (s, 1H, NH);
IR (KBr,
m
cmꢀ1): 3242 (NH), 1649 (C@O), 1593, 1595, 1537, 1433, 815, 740;
1. Dhar, D. N. The Chemistry of Chalcones and Related Compounds; John Wiley &
Sons: New York, 1981.
2. Stu, A. W.; Marby, T. J. Phytochemistry 1971, 10, 2812.
3. (a) Won, S.; Liu, C.; Tsao, L.; Weng, J.; Ko, H.; Wang, J.; Lin, C. Eur. J. Med. Chem.
2005, 40, 103; (b) Rani, P.; Srivastava, V. K.; Kumar, A. Eur. J. Med. Chem. 2004,
39, 449.
4. Lin, Y.; Zhou, Y.; Flavin, M.; Zhou, L.; Niea, W.; Chen, F. Bioorg. Med. Chem. Lett.
2002, 10, 2795.
5. Lahtchev, K. L.; Batovska, D. I.; Parushev, P.; Ubiyvovk, V. M.; Sibirny, A. A. Eur. J.
Med. Chem. 2008, 43, 2220.
HRMS (FAB) m/z calcd for C17H12FNO (M+H)+ 266.0936, obsd 266.0981.
26. Synthesis of indolyl chalcones 4a–j: To a solution of 3-acetylindole 7 (1 mmol)
and appropriate aldehyde 8 (1 mmol) in ethanol (20 mL) was added 10%
sodium hydroxide (2 mL) and refluxed the reaction mixture for 15 h. The
contents of reaction mixture were poured into ice-cold water and neutralized
with dilute hydrochloric acid. The solid so obtained was filtered, dried and
recrystallized from ethanol to afford pure 4a–j.
27. Data for selected compounds: 4a. yield 55%, brown solid, mp 213–215 °C; 1H
NMR (400 MHz, CDCl3): d 4.6 (s, 1H, OH), 6.9–7.26 (m, 4H, Ar-H), 7.27 (d, 1H,
J = 15.52 Hz, H ), 7.30–7.38 (m, 3H, Ar-H), 7.75 (d, 1H, J = 15.5 Hz, Hb), 8.37 (d,
2H, J = 8.08 Hz), 11.02 (s, 1H, NH); IR (KBr,
6. Agarwal, A.; Srivastava, K.; Puri, S. K.; Chauhan, P. M. S. Bioorg. Med. Chem. Lett.
2005, 15, 3133.
a
m
cmꢀ1): 3539–3397 (OH), 3180
(NH), 1612 (C@O), 1587, 1518, 1485, 966, 794, 754; HRMS (FAB) m/z calcd for
C17H13NO2 (M)+ 263.0946 obsd 263.0870. 4b: yield 65%, yellow solid, mp 200–
202 °C; 1H NMR (400 MHz, CDCl3): d 3.16 (s, 3H, OCH3), 6.94 (d, 2H, J = 8.76 Hz,
7. Kayser, O.; Kiderlen, A. F. Phytother. Res. 2001, 15, 148.
8. Aponte, J.; Verastegui, M.; Malaga, E.; Zimic, M.; Quiliano, M.; Vaisberg, A. J.;
Gilman, R. H.; Hammond, G. B. J. Med. Chem. 2008, 51, 6230.
9. Bombardelli, E.; Valent, P. U.S. Patent 6,423,740, 2003.
10. Shah, A.; Khan, A. M.; Qureshi, R.; Ansari, F. L.; Nazar, F. M.; Shah, S. S. Int. J. Mol.
Sci. 2008, 9, 1424.
Ar-H), 7.24–7.29 (m, 2H, Ar-H), 7.35 (d, 1H, J = 15.2 Hz, H ), 7.46–7.48 (m, 1H,
a
Ar-H), 7.61 (d, 2H, J = 8.76 Hz, Ar-H), 7.75 (d, 1H, J = 15.5 Hz, Hb), 8.08 (d, 1H,
J = 3.12 Hz, Ar-H), 8.45–8.48 (m, 1H, Ar-H), 11.24 (s, 1H, NH); IR (KBr,
m
cmꢀ1):
3120 (NH), 1639 (C@O), 1604, 1566, 1543, 1442, 1268, 819, 759; HRMS (FAB)
m/z calcd for C18H15NO2 (M+H)+ 278.1136, obsd 278.1179. 4c: yield 75%, pale
yellow solid, mp 202–205 °C; 1H NMR (400 MHz, CDCl3): d 3.92 (s, 3H, OCH3),
3.94 (s, 3H, OCH3), 6.91 (d, 1H, J = 8.32, Ar-H), 7.16 (d, 1H, J = 1.72 Hz), 7.24 (d,
11. Nowakowska, Z. Eur. J. Med. Chem. 2007, 52, 125.
12. Quintin, J.; Desrivot, J.; Thoret, S.; Menez, P.; Cresteil, T.; Lewin, G. Bioorg. Med.
Chem. Lett. 2009, 19, 167.
13. Meng, Q. C.; Ni, L.; Worsencroft, K. J.; Ye, J.; Weingarten, M. D.; Simpson, J. M.;
Skudlarek, J. W.; Marino, E. M.; Suen, K.; Kunsch, C.; Souder, A.; Howard, R. B.;
Sundell, C. L.; Wasserman, M. A.; Sikorski, J. A. J. Med. Chem. 2007, 50, 1304.
14. Diana, P.; Carbone, A.; Barraja, P.; Montalbano, A.; Martorana, A.; Dattolo, G.;
Gia, O.; Via, L. D.; Cirrincione, G. Bioorg. Med. Chem. Lett. 2007, 17, 2342.
15. Naik, S. R.; Harindran, J.; Varde, A. B. J. Biotechnol. 2001, 88, 1.
16. Pettit, G. R.; Knight, J. C.; Herald, D. L.; Davenport, H. R.; Pettit, R. K.; Tucker, B.
E.; Schmidt, J. M. J. Nat. Prod. 2002, 65, 1793.
17. James, D. A.; Koya, K.; Li, H.; Chen, S.; Xia, Z.; Ying, W.; Wu, Y.; Sun, L. Bioorg.
Med. Chem. Lett. 2006, 16, 5164.
18. Martino, G. D.; Regina, G. L.; Coluccia, A.; Edler, M. C.; Barbera, M. C.; Barancale,
A.; Wilcox, E.; Helmel, E.; Artico, M.; Silvestin, R. J. Med. Chem. 2004, 47, 6120.
19. Kumar, D.; Swapna, S.; Johnson, E. O.; Shah, K. Bioorg. Med. Chem. Lett. 2009, 19,
4492.
1H, J = 16.04 Hz, H ), 7.30–7.36 (m, 3H, Ar-H), 7.43–7.46 (m, 1H, Ar-H), 7.79 (d,
a
1H, J = 15.5 Hz, Hb), 8.04 (s, 1H, Ar-H), 8.51–8.53 (m, 1H, Ar-H). 10.54 (s, 1H,
NH); IR (KBr,
m
cmꢀ1): 3140 (NH), 1641 (C@O), 1579. 1556, 1514, 1440, 1269,
794, 748; HRMS (FAB) m/z calcd for C19H17NO3 (M+H)+ 308.1242, obsd
308.1291. 4d: yield 72%, off-white solid, mp 214–218 °C; 1H NMR (400 MHz,
CDCl3): d 5.96 (s, 2H, CH2), 6.78 (d, 1H, J = 8.0 Hz, Ar-H), 7.05 (d, 1H, J = 1.56 Hz,
Ar-H), 7.09 (d, 1H, J = 18.56 Hz, H ), 7.24–7.38 (m, 4H, Ar-H), 7.69 (d, 1H,
a
J = 15.48 Hz, Hb), 7.93 (d, 1H, J = 2.8 Hz, Ar-H), 8.43–8.46 (m, 1H, Ar-H), 10.51
(s, 1H, NH); IR (KBr,
m
cmꢀ1): 3140 (NH), 1637 (C@O), 1602, 1566, 1517, 1489,
1246, 754; HRMS (FAB) m/z calcd for C18H13NO3 (M+H)+ 292.0929, obsd
292.0981. 4e: yield 80%, light brown solid, mp 191–192 °C; 1H NMR (400 MHz,
CDCl3): d 3.97 (s, 6H, NCH3), 6.89 (d, 1H, J = 8.28 Hz, Ar-H), 7.15 (d, 1H,
J = 1.88 Hz, Ar-H), 7.23 (d, 1H, J = 14.04 Hz, H ), 7.32–7.37 (m, 5H, Ar-H), 7.77
a
(d, 1H, J = 15.52 Hz, Hb), 7.89 (s, 1H, Ar-H), 8.50–8.52 (m, 1H, Ar-H), 10.10 (s,
20. Jeong, T. S.; Kim, K. S.; An, S. J.; Lee, S.; Lee, W. S. Bioorg. Med. Chem. Lett. 2004,
14, 2715.
1H, NH); IR (KBr,
m
cmꢀ1): 3180 (NH), 1612 (C@O), 1573, 1521, 1494, 1435,
798, 754; HRMS (FAB) m/z calcd for C19H18N2O (M+H)+ 291.1400, obsd
291.1506. 4f: yield 55%, pale yellow, mp 180–183 °C; 1H NMR (400 MHz,
21. (a) LeBlane, R.; Dickson, J.; Brown, T.; Stewart, M.; Pati, H. N.; VanDerveer, D.;
Arman, H.; Harris, J.; Pennington, W.; Holt, H. L.; Lee, M. Bioorg. Med. Chem.
2005, 13, 6025; (b) Bonesi, M.; Loizzo, M. R.; Statti, G. A.; Michel, S.; Tillequin,
F.; Menichini, F. Bioorg. Med. Chem. Lett. 2010 (in press).; (c) Chimenti, F.;
Bizzarri, B.; Manna, F.; Balasco, A.; Secci, D.; Chimenti, P.; Granese, A.; Rivanera,
D.; Lilli, D.; Scaltrito, M. M.; Brenciaglia, M. I. Bioorg. Med. Chem. Lett. 2005, 15,
603.
22. (a) Black, D. S.; Renu, B. D.; Kumar, N. Aust. J. Chem. 1992, 45, 611; (b) Manna, F.;
Chimenti, F.; Bolasco, A.; Bizzarri, B.; Filippelli, W.; Filippelli, A.; Gagliardi, L.
Eur. J. Med. Chem. 1999, 34, 245.
23. (a) Bhagat, S.; Sharma, R.; Sawant, D. M.; Sharma, L.; Chakraborti, A. K. J. Mol.
Catal. A: Chem. 2006, 244, 20; (b) Bhagat, S.; Sharma, R.; Chakraborti, A. K. J. Mol.
Catal. A: Chem. 2006, 260, 235; (c) Srinivasan, B.; Johnson, T. E.; Lad, R.; Xing, C.
J. Med. Chem. 2009, 52, 7228.
24. Synthesis of indolyl chalcones 3a–m: A mixture of indol-3-carboxaldehyde 5
(1 mmol) and appropriate acetophenone 6 (1 mmol) in anhydrous ethanol
(30 mL) was refluxed in presence of piperidine (0.5 mL) for 20 h. The reaction
mixture was poured onto crushed ice, neutralized with acetic acid to afford
solid compound which was filtered and recrystallized from ethanol to obtain
pure 3a–m.
DMSO-d6): d 7.13–7.26 (m, 5H, Ar-H), 7.23 (d, 1H, J = 14.04 Hz, H ), 7.26 (d, 1H,
a
J = 7.2 Hz), 7.47 (d, 1H, J = 15.98 Hz, Hb), 8.15 (d, 1H, J = 8.00 Hz, Ar-H), 8.28 (d,
2H, J = 8.00 Hz, Ar-H), 9.92 (s, 1H, Ar-H), 11.80 (s, 1H, NH), 11.89 (s, 1H, NH); IR
(KBr,
m
cmꢀ1): 3197 (NH), 1641 (C@O), 1612, 1577 1529, 1444, 788, 754; HRMS
(FAB) m/z calcd for C19H14N2O (M+H)+ 287.1140, obsd 287.2105. 4g: yield 55%,
dark brown solid, mp 210–213 °C; 1H NMR (400 MHz, CDCl3): d 7.28–7.32 (m,
2H, Ar-H), 7.47–7.52 (m, 3H, Ar-H), 7.60 (d, 1H, J = 15.2 Hz, H ), 7.68 (d, 1H,
a
J = 15.6 Hz, Hb), 8.11 (d, 1H, J = 3.16 Hz), 8.45–8.48 (m, 1H, Ar-H), 8.66 (d, 2H,
J = 5.96 Hz, Ar-H), 11.37 (s, 1H, NH); IR (KBr,
m
cmꢀ1): 3196 (NH), 1649 (C@O),
1589, 1570, 1517, 1448, 979, 794, 748; HRMS (FAB) m/z calcd for C16H12N2O
(M+H)+ 249.0983, obsd 249.1031. 4h: yield 60%, yellow solid, mp 126–130 °C;
1H NMR (400 MHz, CDCl3): d 3.84 (s, 3H, NCH3), 3.86 (s, 3H, OCH3), 6.91 (d, 2H,
J = 8.76 Hz, Ar-H), 7.26 (d, 1H, J = 15.56 Hz, H ), 7.30–7.35 (m, 3H, Ar-H), 7.58
a
(d, 2H, J = 8.8 Hz, Ar-H), 7.80 (d, 1H, J = 15.52 Hz, Hb), 7.86 (s, 1H, Ar-H), 8.48–
8.52 (m, 1H, Ar-H); IR (KBr,
m
cmꢀ1): 3040 (C–H), 1644 (C@O), 1569, 1531,
1511, 1454, 1259, 813, 769; HRMS (FAB) m/z calcd for C19H17NO2 (M+H)+
292.1293, obsd 292.1335.
28. A-549, a human epithelial cell line derived from a lung carcinoma (doubling
time; 20–24 h), was obtained from American Type Culture Collection. A-549
were maintained in Dulbecco’s modified Eagle medium with high glucose
(Invitrogen, Carlsbad, CA, USA) containing 10% fetal bovine serum (FBS) with
25. Data for selected compounds: 3a: yield 65%, dark brown solid, mp 147–148 °C;
1H NMR (400 MHz, CDCl3): d 4.10 (br s, 1H, OH), 6.54 (d, 1H, J = 8.76 Hz, Ar-H),
7.20–7.25 (m, 2H, Ar-H), 7.49 (d, 1H J = 8.32 Hz, Ar-H), 7.59 (d, 1H, J = 14.64 Hz,
100 U/mL penicillin and 100 lg streptomycin. PaCa-2, a human pancreatic
H ), 7.64–7.75 (m, 1H, Ar-H), 8.06–8.08 (m, 3H, Ar-H), 8.09 (d, 1H, J = 14.48 Hz,
a

D. Kumar et al. / Bioorg. Med. Chem. Lett. 20 (2010) 3916–3919
3919
carcinoma cell line (doubling time; 24 h), was obtained from Health Science
Research Resources Bank (HSRRB) (Osaka, Japan). PaCa-2 were cultured in
well, and PC-3 cells were plated 1 ꢁ 104 cells well in 96-well plates, the day
before chalcones (3 and 4) treatment. All the compounds were dissolved in
dimethylsulfoxide (DMSO) at room temperature. Aliquots of these stock
solutions at 100 mM were stored at ꢀ20 °C. The cell viability was measured by
the cell Counting Kit-8 (Dojin, Kumamoto, Japan) using a spectrophotometer
(xMark; Bio-Rad, Hercules, CA, USA) at 450 nm after 24 h and 48 h of chalcones
treatment. Final concentrations of the vehicle were 1% DMSO in culture
medium. The cell viability of A-549, PaCa-2 and PC-3 human cancer cells was
inhibited by the chalcone analogues 3 and 4 for 24–48 h in a dose-dependent
manner.
minimum essential medium with Earle’s salts,
acids (Nacali Tesque Inc., Kyoto, Japan) containing 10% FBS with 100 U/mL
penicillin and 100 g streptomycin. PC-3, an androgen-independent human
L-Gln and non-essential amino
l
prostatic adenocarcinoma cell line (doubling time; 48–60 h), was obtained
from HSRRB. PC-3 were maintained in RPMI-1640 (Wako Pure Chem. Ind. Ltd,
Osaka, Japan) containing 10% FBS with 100
streptomycin. Cell lines were kept at 37 °C in
consisting of air (CO2 5%). A-549 and PaCa-2 cells were plated 5000 cells per
l
g/mL penicillin and 100
lg
a
humidified atmosphere