Synthesis and cytotoxic activity of novel pyrazoline derivatives against human lung tumor cell line (A549)

Article abstract of DOI:10.1002/jccs.200700014

In the present investigation, a series of 5-(-4-(substituted)phenyl)-3-(4- hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-2-toluidino methane thione and 5-(substituted)phenyl-3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1- pyrazolyl-2-methoxy anilino m

Full text of DOI:10.1002/jccs.200700014

Journal of the Chinese Chemical Society, 2007, 54, 81-86
81
Synthesis and Cytotoxic Activity of Novel Pyrazoline Derivatives against
Human Lung Tumor Cell Line (A549)
Mohammad Shahar Yar,a* Anees Ahmad Siddiqui,a Mohamed Ashraf Ali,a
Vedigounder Muruganb and Raghu Chandrashekharb
aFaculty of Pharmacy, Jamia Hamdard University, Department of Pharmaceutical Chemistry,
Hamdard Nagar, New Delhi-110062, India
bDepartment of Pharmaceutical Chemistry, J.S.S College of Pharmacy, Ooty-643001, India
In the present investigation, a series of 5-(-4-(substituted)phenyl)-3-(4-hydroxy-3-methylphenyl)-
4,5-dihydro-1H-1-pyrazolyl-2-toluidino methane thione and 5-(substituted)phenyl-3-(4-hydroxy-3-
methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-2-methoxy anilino methane thiones were synthesized and
were examined against human lung tumor cell line (A549) in vitro using the MTT assay system. Among
those tested, 5-(4-flurophenyl)-3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-2-toluidino
methane thione & 5-(4-chlorophenyl)-3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-2-
methoxy anilino methane thione showed more potent cytotoxicity against human lung tumor cell line
(A549) than the other synthesized compounds.
Keywords: Cytotoxicity; Pyrazoline; Anti-proliferation.
INTRODUCTION
Effective treatment of cancer results from destruction
mains a disease with poor prognosis and the primary cause
of cancer-related death in both men and women despite re-
cent advances made in drug development. The develop-
ment or presence of resistance to chemotherapeutic agents
is a major obstacle to the effective treatment of lung cancer.
Identifying the molecular determinants of sensitivity and
resistance to chemotherapy is expected to improve the ther-
apeutic efficacy. A literature survey reveals pyrazoline de-
rivatives are active against many tumor cell lines.5,6 The
current work describes the synthesis of novel pyrazoline
moiety with encouraging cytotoxic activity against human
lung tumor cell lines (A 549).
of the cancer cells, which is a result of the cytotoxicity of a
drug against proliferating cells. Most of the clinically avail-
able anticancer drugs interfere with DNA function to exert
their cytotoxicity. DNA intercalators represent an impor-
tant class of anticancer drugs.1 Lung cancer is the most fre-
quent cause of cancer-related death and accounts for more
than a million deaths yearly worldwide with non-small cell
lung cancer (NSCLC) accounting for 75-85% of lung can-
cer.2,3 The pathogenesis of lung cancer involves the accu-
mulation of multiple molecular abnormalities, particularly
with the exposure to smoking. These alterations include the
genetic mutations, chromosomal changes with consequent
inactivation of tumor suppressor genes and over activity of
signal transduction cascades. Apoptosis (programmed cell
death), not only occurs naturally during development and
differentation, but also acts to eliminate damaged cells af-
ter injury.4 Molecular studies of lung cancer have provided
new avenues for early diagnosis and therapeutic strategies;
however, certain patients are still plagued by rapid disease
recurrence and progression, and there has been no signifi-
cant improvement in their overall survival. Therefore, it re-
RESULTS AND DISCUSSION
Chemistry
5-(4-(Substituted)phenyl)-3-(4-hydroxy-3-methyl-
phenyl)-4,5-dihydro-1H-1-pyrazolyl-2-toluidinomethane-
thione and 5-(substituted)phenyl-3-(4-hydroxy-3-methyl-
phenyl)-4,5-dihydro-1H-1-pyrazolyl-2-methoxyanilino-
methanethione (5a-k) and (6a-k) described in this study are
shown in Tables 1 and 2, and a reaction sequence for the
preparation is outlined in Scheme I. The chalcones were
* Corresponding author. Tel: +91-9899452373; E-mail: yarmsy@rediffmail.com

82 J. Chin. Chem. Soc., Vol. 54, No. 1, 2007
Shahar Yar et al.
Table 1. Physical constants of the synthesized compounds
CH3
CH3
OMe
NH
S
S
OH
OH
N
N
N
NH
CH3
N
R
R
5a-k
6a-k
Compound
R
Yield (%)
M.P (°C)
Mol. Formula
Mol. Wt
5a
5b
5c
5d
5e
5f
4-Methoxy phenyl-
4-Chloro phenyl-
4-Dimethylamino phenyl-
Phenyl-
74
70
72
80
82
85
92
85
77
82
90
82
80
75
80
77
72
82
72
70
44
80
144
131
104
121
102
103
196
115
164
104
205
124
153
115
234
197
106
142
156
172
194
169
C25H25N3O2S
C24H22N3OSCl
C26H28N4OS
431.55
435.97
444.59
401.52
461.57
491.60
420.52
435.97
470.41
446.52
392.48
447.55
451.96
460.59
417.52
477.57
507.60
436.52
451.96
486.41
462.52
407.48
C24H23N3OS
3,4-Dimethoxy phenyl-
3,4,5-Trimethoxy phenyl-
4-Fluoro phenyl-
2-Chloro phenyl-
2,6-Dichloro phenyl-
3-Nitro phenyl-
C26H27N3O3S
C27H29N3O4S
C24H22N3OSF
C24H22N3OSCl
C24H21N3OSCl2
C24H22N4O3S
C22H21N3O2S
C25H25N3O3S
C24H22N3O2SCl
C26H28N4O2S
C24H23N3O2S
C26H27N3O4S
C27H29N3O5S
C24H22N3O2SF
C24H22N3O2SCl
C24H21N3O2SCl2
C24H22N4O4S
C22H21N3O3S
5g
5h
5i
5j
5k
6a
6b
6c
6d
6e
6f
Furfuryl-
4-Methoxy phenyl-
4-Chloro phenyl-
4-Dimethylamino phenyl-
Phenyl-
3,4-Dimethoxy phenyl-
3,4,5-Trimethoxy phenyl-
4-Fluoro phenyl-
2-Chloro phenyl-
2,6-Dichloro phenyl-
3-Nitro Phenyl-
6g
6h
6i
6j
6k
Furfuryl-
prepared by reacting 3-methyl-4-hydroxy acetophenone
with an appropriate aldehyde in the presence of base by
conventional Claisen-Schmidt condensation. Reaction be-
tween newly synthesized chalcones with hydrazine hydrate
in ethanol led to synthesis of novel pyrazolines (4a-k),
which on treatment with various aryl isothiocyanates af-
forded respective 3,5-disubstituted pyrazolines (5a-k) &
(6a-k) in 65-85% yield. The purity of the compounds was
checked by TLC and elemental analyses. Spectral data
(1H-NMR & IR) of all the synthesized compounds were in
full agreement with the proposed structures.
are summarized in Table 2. Among the newly synthesized
compounds, electron rich group substituted analogue 7 (p-
fluro) showed potent inhibitory activities with a PIC50 value
of 1.073. Next in the order 2 (p-chloro) showed good inhib-
itory activity against human lung tumor cell lines (A 549),
with a PIC50 value of 1.011. However, furfuryl, 3-NO2, 2-Cl
and 2,6-dichlorosubstituted pyrazolines resulted decreases
in activity. On the other hand, the methoxy group mono
substituted at the 4-position, disubstituted at the 3,4-posi-
tion and tri-substituted 3,4,5-position resulted in decreases
of the inhibitory activity. These reports clearly showed that
the presence of fluro groups at the pyrazoline nucleus causes
remarkable improvement in antiproliferative activity.
Antiproliferative Activity
The ring substituted pyrazoline derivatives (5a-k)
and (6a-k) were tested for their anti-proliferative activity
against in-vitro human lung tumor cell lines (A 549) using
the MTT assay system. The resulting PIC50 values of cancer
cell growth inhibition by the novel pyrazoline analogues
CONCLUSION
Among the newer derivatives, compounds 5g and 5b

Cytotoxic Activity of Novel Pyrazoline Derivatives
J. Chin. Chem. Soc., Vol. 54, No. 1, 2007 83
Table 2. Anti-proliferative activity of the synthesized compounds against human lung tumor cell lines
(A 549)
CH3
OMe
NH
S
CH3
S
OH
OH
N
N
N
NH
CH3
N
R
R
5a-k
6a-k
Compound
R
IC50
mM/mL
PIC50 Experimental
5a
5b
5c
5d
5e
5f
4-Methoxy phenyl-
4-Chloro phenyl-
90.5
42.5
72.5
114
146
164
35.5
72.5
84.25
98.75
72.5
94
0.2097
0.0974
0.1630
0.2839
0.3163
0.3336
0.0844
0.1662
0.1790
0.2211
0.1847
0.2100
0.1902
0.2518
0.2922
0.1779
0.6783
1.0110
0.7876
0.5468
0.4998
0.4767
1.0730
0.7791
0.7469
0.6553
0.7334
0.6777
0.7206
0.5988
0.5343
0.7496
0.7323
0.8618
0.7412
0.8177
0.6565
0.7527
4-Dimethylamino phenyl-
Phenyl-
3,4-Dimethoxy phenyl-
3,4,5-Trimethoxy phenyl-
4-Fluoro phenyl-
2-Chloro phenyl-
2,6-Dichloro phenyl-
3-Nitro phenyl-
5g
5h
5i
5j
5k
6a
6b
6c
6d
6e
6f
Furfuryl-
4-Methoxy phenyl-
4-Chloro phenyl-
4-Dimethylamino phenyl-
Phenyl-
86
116
122
85
3,4-Dimethoxy phenyl-
3,4,5-Trimethoxy phenyl-
4-Fluoro phenyl-
2-Chloro phenyl-
2,6-Dichloro phenyl-
3-Nitro phenyl-
94
00.18577
0.1374
0.1814
0.1521
0.2205
0.1766
6g
6h
6i
60
82
74
6j
102
72
6k
Furfuryl-
showed promising activity and the rest showed moderate to
good activity against human lung tumor cell lines (A 549).
It is conceivable that derivatives showing anti-proliferative
activity can be further modified to exhibit better anticancer
chemotherapeutic agents. Further studies to acquire more
information about quantitative structure-activity relation-
ships (QSAR) are in progress in our laboratory.
Perkin-Elmer 1720 FT-IR spectrometer (KBr Pellets). 1H-
NMR spectra were recorded on a Bruker AC 300 MHz
spectrometer using TMS as internal standard in DMSO/
CDCl3.
General Procedure
4-Hydroxy-3-methyl acetophenone was dissolved in
ethanol. Then, a solution of sodium hydroxide (30%, 5 mL)
and suitable substituted aldehydes in 10 mL of Pet. ether
was added to the resulting solution with continuous stir-
ring. The resulting solution was allowed to stand overnight.
After 4 h stirring, it was then poured into ice-cold water
then neutralize with Hcl. The solid separate was filtered
off, dried and purified from ethanol (3a-k).
EXPERIMENTAL
All chemicals were supplied by E. Merck (GER-
MANY) and S.D fine chemicals (India). Melting points
were determined by open tube capillary method and are un-
corrected. Purity of the compounds was checked on thin
layer chromatography (TLC) plates (silica gel G) in the sol-
vent system toluene-ethyl formate-formic acid (5:4:1) and
benzene-methanol (8:2); the spots were located under io-
dine vapors or UV light. IR spectra were obtained on a
General procedure for 4-[5-(substituted)phenyl-4,5-
dihydro-1H-3-pyrazolyl]-2-methylphenol (4a-k)
To a solution of chalcone (3a-k) in ethanol, hydrazine
hydrate (99%) was added dropwise. The reaction mixture

84 J. Chin. Chem. Soc., Vol. 54, No. 1, 2007
Scheme I Protocol for the synthesis
Shahar Yar et al.
1
was heated under reflux for 7 hr and then cooled and poured
onto crushed ice. The solid pyrazoline product was filtered
and recrystalized from ethanol (4a-k).
(C-N), 1130 (C=S), 3220 (NH); H-NMR (DMSO-d6)
ppm: 8.7 (1H, s, OH), 2.8 (6H, s, CH3), 7.2-7.4 (11H, m, ar-
omatic), 5.2 (1H, s, NH), 3.9 (6H, s, N(CH3)2), 2.2 (2H, s,
CH2). Cal/Anal [C (70.24) 70.24, H (6.35) 6.34, N (12.60)
12.56].
General procedure for 5-(4-(substituted)phenyl)-3-(4-
hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-
2-toluidinomethane thione
(5d) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.0 (IH, s, NH), 9.7 (1H, s, OH), 7.2-7.8 (12H, m, aro-
matic), 2.8 (6H, s, CH3), 2.2 (2H, s, CH2). Cal/Anal [C
(71.79) 71.76, H (5.77) 5.74, N (10.46) 10.42].
(5e) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.2 (1H, s, NH), 8.7 (1H, s, OH), 7.2-7.4 (10H, m, aro-
matic), 3.9 (6H, s, OCH3 × 2), 2.8 (6H, s, CH3), 2.2 (2H, s,
CH2). Cal/Anal [C (67.66) 67.63, H (5.90) 5.85, N (9.10)
9.08].
(5f) IR: (KBr) cm-1 3317 (OH), 1596 (C=N), 1320
(C-N), 1132 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.4 (1H, s, NH), 8.7 (1H, s, OH), 7.2-7.4 (9H, m, aro-
matic), 3.9 (9H, s, OCH3 × 3), 5.2 (1H, s, NH) 2.8 (6H, s,
CH3), 2.2 (2H, s, CH2).Cal/Anal [C (65.97) 65.94, H (5.95)
5.93, N (8.55) 8.53].
To a solution of chalcone (4a-k) in ethanol (20 mL)
was added 2-methyl aryl isothiocyanate (0.01 mol), and the
reaction mixture was refluxed for 4 hr. The reaction mix-
ture was cooled and then poured onto crushed ice. Then
solid mass separate out was filtered, washed with water and
purified from ethanol (5a-k).
(5a) IR: (KBr) cm-1 3307 (OH), 1596 (C=N), 1320
(C-N), 1130 (C=S), 3224 (NH); 1H-NMR (DMSO-d6) ppm:
10.0 (IH, s, NH), 9.7 (1H, s, OH), 7.2-7.4 (11H, m, aro-
matic), 3.9 (3H, s, OCH3), 2.8 (6H, s, CH3), 2.2 (2H, s,
CH2), Cal/Anal [C (69.58) 69.56, H (5.84) 5.86, N (9.74)
9.72].
(5b) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 770
1
(C-Cl), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
(DMSO-d6) ppm: 10.0 (IH, s, NH), 9.5 (1H, s, OH), 7.2-7.4
(11H, m, aromatic), 2.8 (6H, s, CH3), 2.2 (2H, s, CH2).
Cal/Anal [C (66.12) 66.10, H (5.09) 5.07, N (9.64) 9.60].
(5c) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(5g) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 824
1
(C-F), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
(DMSO-d6) ppm: 10.0 (1H, s, NH), 8.7 (1H, s, OH), 7.2-7.9

Cytotoxic Activity of Novel Pyrazoline Derivatives
J. Chin. Chem. Soc., Vol. 54, No. 1, 2007 85
(11H, m, aromatic), 2.8 (6H, s, CH3), 2.2 (2H, s, CH2),
Cal/Anal [C (68.71) 68.72, H (5.29) 5.26, N (10.02) 10.00].
(5h) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 770
(11H, m, aromatic), 3.9 (3H, s, OCH3), 3.9 (6H, s, N(CH3 ×
2), 4.4 (1H, s, CH), 2.2 (2H, s, CH2). Cal/Anal [C (63.40)
63.38, H (5.73) 5.70, N (11.37) 11.35].
(6d) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.10 (1H, s, NH), 9.7 (1H, s, OH), 7.2-7.4 (12H, m, aro-
matic), 4.24 (1H, s, CH), 3.9 (3H, s, OCH3), 2.8 (3H, s,
CH3), 2.2 (2H, s, CH2). Cal/Anal [C (69.04) 69.00, H (5.55)
5.53, N (10.06)10.02].
1
(C-Cl), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
(DMSO-d6) ppm: 10.0 (1H, s, NH), 9.4 (1H, s, OH), 7.2-7.4
(11H, m, aromatic), 2.8 (6H, s, CH3), 2.2 (2H, s, CH2).
Cal/Anal [C (66.12) 66.10, H (5.09) 510, N (9.64) 9.62].
(5i) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 770
1
(C-Cl), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
(DMSO-d6) ppm: 10.0 (1H, s, NH), 9.7 (1H, s, OH), 7.2-7.4
(10H, m, aromatic), 2.8 (6H, s, CH3), 2.2 (2H, s, CH2),
Cal/Anal [C (61.28) 61.26, H (4.50) 4.52, N (8.93) 8.90].
(5j) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
13.5 (1H, s, NH), 8.6 (1H, s, OH), 2.4 (6H, s, CH3), 7.2-7.4
(11H, m, aromatic), 2.1 (2H, s, CH2). Cal/Anal [C (64.56)
64.53, H (4.97) 4.94, N (12.55) 12.53].
(5k) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.0 (1H, s, NH), 9.2 (1H, s, OH), 2.8 (6H, s, CH3), 7.8-8.0
(Furan), 7.2-7.4 (7H, m, aromatic), 2.2 (2H, s, CH2).
Cal/Anal [C (67.50) 67.46, H (5.41) 5.40, N (10.73) 10.72].
(6e) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.10 (1H, s, NH), 8.7 (1H, s, OH), 2.8 (3H, s, CH3), 7.2-
7.4 (11H, m, aromatic), 3.9 (9H, s, OCH3 × 3), 4.24 (1H, s,
CH), 2.2 (2H, s, CH2). Cal/Anal [C (65.39) 65.39, H (5.70)
5.64, N (8.80) 8.76].
(6f) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.10 (1H, s, NH), 9.7 (1H, s, OH), 2.8 (3H, s, CH3), 7.2-
7.4 (11H, m, aromatic), 3.9 (9H, s, OCH3 × 4), 4.24 (1H, s,
CH), 2.2 (2H, s, CH2). Cal/Anal [C (63.89) 63.86, H (5.76)
5.72, N (8.28) 8.24].
(6g) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 820
1
(C-F), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
General procedure for 5-(substituted)phenyl-3-(4-hy-
droxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-2-
methoxyanilino methane thione
(DMSO-d6) ppm: 10.10 (1H, s, NH), 9.4 (1H, s, OH), 2.8
(6H, s, CH3), 3.9 (9H, s, OCH3), 7.2-7.4 (11H, m, aro-
matic), 2.2 (2H, s, CH2), 5.2 (1H, s, NH). Cal/Anal [C
(66.19) 66.16, H (5.09) 5.06, N (9.65) 9.64].
(6h) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
13.0 (1H, s, NH), 9.2 (1H, s, OH), 7.8-8.0 (Furan), 7.2-7.4
(7H, m, aromatic), 3.8 (9H, s, OCH3), 2.5 (6H, s, CH3), 2.2
(2H, s, CH2). Cal/Anal [C (64.85) 64.82, H (5.19) 5.16, N
(10.31)10.29].
To a solution of chalcone (4a-k) in ethanol (20 mL)
was added 2-methoxy-aryl isothiocyanate (0.01 mol), and
the reaction mixture was refluxed for 4 hr. The reaction
mixture was cooled and then poured onto crushed ice. Then
solid mass separate out was filtered, washed with water and
purified from ethanol (6a-k).
(6a) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.0 (1H, s, NH), 9.7 (1H, s, OH), 6.5-8.4 (11H, m, aro-
matic), 5.3 (1H, s, CH), 2.5 (3H, s, CH3), 3.3 (6H, s, OCH3
× 2), 1.6 (2H, s, CH2). Cal/Anal [C (67.09) 67.04, H (5.63)
5.62, N (9.39) 9.36].
(6i) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 770
1
(C-Cl), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
(DMSO-d6) ppm: 12.10 (1H, s, NH), 12.0 (1H, s, OH), 2.8
(6H, s, CH3), 3.9 (9H, s, OCH3), 7.2-7.4 (11H, m, aro-
matic), 2.2 (2H, s, CH2), 5.2 (1H, s, NH). Cal/Anal [C
(63.78) 63.75, H (4.91) 4.88, N (9.30) 9.28].
(6b) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 770
1
(C-Cl), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
(6j) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 770
1
(C-Cl), 1320 (C-N), 1130 (C=S), 3220 (NH); H-NMR
(DMSO-d6) ppm: 10.0 (1H, s, NH), 9.9 (1H, s, OH), 6.5-8.4
(11H, m, aromatic), 5.3 (1H, s, CH), 2.5 (3H, s, CH3), 3.8
(3H, s, OCH3), 2.5 (2H, s, CH2). Cal/Anal [C (63.78) 63.75,
H (4.91) 4.90, N (9.30) 9.28].
(6c) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:
10.0 (1H, s, NH), 9.7 (1H, s, OH), 2.8 (3H, s, CH3), 7.2-7.4
(DMSO-d6) ppm: 10.10 (1H, s, NH), 9.7 (1H, s, OH), 2.8
(6H, s, CH3), 3.9 (9H, s, OCH3), 7.2-7.4 (10H, m, aro-
matic), 2.2 (2H, s, CH2), 5.2 (IH, s, NH). Cal/Anal [C
(59.26) 59.23, H (4.35) 4.36,N (8.64) 8.60].
(6k) IR: (KBr) cm-1 3307 (OH), 1590 (C=N), 1320
(C-N), 1130 (C=S), 3220 (NH); 1H-NMR (DMSO-d6) ppm:

86 J. Chin. Chem. Soc., Vol. 54, No. 1, 2007
Shahar Yar et al.
10.10 (1H, s, NH), 9.7 (1H, s, OH), 2.8 (6H, s, CH3), 3.9
(9H, s, OCH3), 7.2-7.4 (11H, m, aromatic), 2.2 (2H, s,
CH2). Cal/Anal [C (62.32) 62.30, H (4.79) 4.76, N (12.11)
12.10].
percentage inhibition was calculated using the following
formula.
Absorbance of sample
Absorbance of control
é
ù
Growth Inhibition % = 100
´ 100
ê
ú
ë
û
Biological Assay
Cytotoxic Assay
The percentage inhibition was plotted against con-
centration, and the CTC50 (concentration required to re-
duce viability by 50%) value for each cell line was calcu-
lated.
The cytotoxicity assay was carried out using 0.1-mL
of cell suspension containing 10,000 cells seeded in each
well of a 96 well microtiter plate (Nunc and Tarsons). Fresh
medium containing different concentrations of the extracts
was added 24 h after seeding. Control cells were incubated
without the test extracts and with DMSO (solvent). The
very little percentage of DMSO present in the wells (maxi-
mal 0.2%) did not affect the experimental results. The
microtiter plates were incubated at 37 °C in a humidified
incubator with 5% CO2 for a period of 3 days. Twelve wells
were used for each concentration of the extracts. Morpho-
logical changes were examined using an inverted micro-
scope. The cells were observed at different time intervals
during the incubation period in the presence or absence of
the compound. Cellular viability was determined by using
the standard MTT (3-(4,5-dimethylthiozole-2-yl)-2,5-di-
phenyl tetrazolium bromide) assay.7
Data Set
These cytotoxic values (IC50) were transformed to
pIC50 (-log IC50, concentration in molarity) for statistical
analysis. The cytotoxic data of these compounds are listed.
ACKNOWLEDGEMENTS
The author (M. Shahar Yar) wishes to express his
thanks to the University Grant Commission-New Delhi, In-
dia, for the research award and to Dr. Kiran Smith, National
Cancer Institute-USA, for valuable suggestions.
MTT Assay
Received February 17, 2006.
MTT assay is based on the reduction of the soluble
MTT into a blue purple formazan product mainly by mito-
chondrial reductase activity inside living cells. The number
of viable cells were found to be proportional to the extent of
formazan production for the cell lines used in this study.
After incubation, the solutions in four wells of each con-
centration were discarded and 50 ml of a solution of 2
mg/mL of MTT (Sigma Chemicals Co., St. Louis, MO,
USA) in DMEM (without phenol red) was added and the
cultures were incubated for an additional 3 h at 37 °C. The
supernatant was removed and the cells were treated with
propanol (100 ml/well) and kept aside for 10 min at room
temperature. The absorbance was read on a microtiter plate
reader (Bio-Rad, Model 550) at a wavelength of 540 nm,
and the mean absorbance from four wells was recorded.
Mean absorbance taken from cells grown in the absence of
the extracts was taken as 100% cell survival (control). The
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