W. Liu et al. / Bioorg. Med. Chem. Lett. 22 (2012) 2701–2704
2703
5-FU (IC50 = 4.7
6b–d were comparable to this reference.
In contrast, at the MDA-MB 231 cell line only 6e showed an
l
M) the IC50 values of about 5
l
M determined for
while in vivo anti-inflammatory tests indicated stronger inhibition
than ibuprofen in the xylene-induced ear swelling assay. Further
investigations on structural optimization and biological activities
with these derivatives are still underway in our laboratory.
IC50 = 10.6
(IC50 = 4.7
l
l
M higher than 5-FU (IC50 = 9.6
M) possessed high cytotoxicity. At HT-29 cells, com-
M) were slightly more active than
M), whereas the growth inhibitory effects of 6a
lM). Especially 6d
pounds 6b–d (IC50 = 6.2–6.7
l
Acknowledgments
5-FU (IC50 = 7.3
l
and 6e were significantly lower (IC50 values of 9.6 and 9.2
respectively).
l
M,
The authors are grateful for the financial supports of National
Natural Science Foundation of China (No. 30973638) and Jiangsu
Enterprise-Academics-Research Innovation Found-Prospective
Joint Research Project (No. BY2011158). The China scholarship
council and the Deutsche Forschungsgemeinschaft (FOR 630) are
also gratefully acknowledged.
Next, the anti-inflammatory effects of the thiourea derivatives
were studied in vivo using the well-known xylene-induced ear
swelling assay in mice.28,32 Overnight fasted mice (12 h) of either
sex weighing approximately 20 g were divided into groups of eight
animals each. One group of mice, which served as control was only
given vehicle (0.5% CMC in water in a volume of 20 mL/kg). Test
compounds (4 mg/kg b.w.) and ibuprofen (4 and 30 mg/kg b.w.)
suspended in vehicle (20 mL/kg) were administered intraperitone-
ally (ip) to respective groups for 5 days. 30 min after the last
administration, 0.1 mL of xylene was applied to the anterior and
posterior surfaces of the right ear. The left ear was considered as
control. One hour after xylene application, mice were killed and
both ears were removed. Circular sections were taken, using a cork
borer with a diameter of 9 mm, and measured. The degree of ear
swelling was calculated based on the weight of left ear without
xylene.
As shown in Table 3, 6a–e exhibited good anti-inflammatory
activity at a dose of 4 mg/kg b.w. Especially, 6a and 6b showed
the highest anti-inflammatory inhibition rate with 26.08% and
30.40%, respectively. In addition, the target compounds 6a–e
(13.04 to 30.40% inhibition) were more active than ibuprofen
(8.69% inhibition) at the same dose (4 mg/kg b.w.). To achieve
the same activity as our compounds ibuprofen had to be used in
a dose of 30 mg/kg b.w. (39.13% inhibition).
References and notes
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Finally, in order to study if the inhibition of COX-1/2 enzymes
contributed to the anti-inflammation in vivo, we evaluated the
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10
indomethacin was much more active (COX-1 inhibition: 56%;
COX-2 inhibition: 100%; concentration: 10 M). Unfortunately, at
a concentration of 10 M, 6b caused only weak COX inhibition
lM) and was inactive at COX-2 while the second reference
l
l
(COX-1 (11.6%) and COX-2 (11.1%)). On the basis of these observa-
tions it could be assumed that the new compounds might inhibit
other enzymes, which were responsible for modifications of
arachidonic acid to produce inflammatory molecules such as pros-
tanoids and leukotrenes.28,29
In conclusion, a series of thiourea derivatives was synthesized
and tested for tumor cell growth inhibitory effects as well as for
anti-inflammatory activity. Preliminary in vitro bioassay data doc-
umented that all compounds represent potential antitumor drugs,
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27. General procedure for the synthesis of 6a–e. The flask was charged with 10 mL
of absolute ethanol, 1.0 g (3.4 mmol) of desloratadine and 6.8 mmol of RNCS.
The resulting solution was stirred at rt for over 1 h. Then the white suspension
was filtered under suction and the solid was washed with a small amount of
cold ethanol to obtain the white product.
Table 3
ꢀ
Effect of the compounds on xylene-induced ear swelling in mice (n = 8, x S)
Dose (mg/kg b.w.) Swollen extent; weight (g) Inhibition (%)
Control
6a
6b
6c
6d
6e
0.023 0.003
0.017 0.005*
0.016 0.006*
0.018 0.004*
0.020 0.004
0.018 0.008
0.021 0.002*
0.014 0.004*
4-(8-Chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-ylidene)
-N-methyl-1-piperidinecarbothioamide (6a).Yield: 70%; A white solid; mp:
234ꢀ236 °C; ESI-MS m/z: 384.1 [M+H]+, 406.0 [M+Na]+, 422.1 [M+K]+; IR
(cmꢁ1): 3468, 3420, 3283, 2909, 2837, 1634, 1588, 1535, 1466, 1431, 138,
1347, 1257, 1205, 1055, 997, 803; 1H NMR (CDCl3): d 2.41ꢀ2.45 (m, 2H,
@CCH2); 2.51ꢀ2.61 (m, 2H, @CCH2); 2.81ꢀ2.85 (m, 2H, NCH2); 3.18 (s, 3H,
SCH3); 3.36ꢀ3.41 (m, 2H, NCH2); 3.66ꢀ3.68 (m, 2H, CH2); 4.14 (m, 2H, CH2);
5.64 (s, 1H, NH); 7.19ꢀ7.24 (m, 4H, Ar-H, pyridin-H); 7.58 (dd, 1H, J = 4.5 Hz,
pyridin-H); 8.46 (dd, 1H, J = 2.9 Hz, pyridin-H); Anal. Calcd for C21H22ClN3S: C,
65.69; H, 5.78; N, 10.94. Found C, 65.40; H, 5.82; N, 10.92.
4
4
4
4
4
4
26.08
30.40
21.74
13.04
21.74
8.69
Ibuprofen
Ibuprofen 30
39.13
*
P <0.05, data were subjected to one-way ANOVA.