6940
J. Yan et al. / Bioorg. Med. Chem. 17 (2009) 6937–6941
namaldehyde in
a
-position with the group leads to decrease anti-
the catalytic triad and the active site defined as 10 Å around it.
The GoldScore (Gscore) was opted to rank order the docked confor-
mations. Ligplot 4.4 3 was used to generate hydrogen bonds and
hydrophobic interactions between the best-docked conformational
pose of the ligand and the amino acid residues in the active site of
the protein.
AChE activity. The results provided new insights into the factors
affecting AChE–ligand interaction in the active gorge. But differ-
ences in the structures and conformations of these enzymes must
take into consideration.
4. Experimental
Acknowledgments
4.1. General procedures
We thank Dr. X.L. Pan (Kunming Institute of Botany, CAS) and
Dr. Abiodun Falodun (University of Benin, Nigeria) for their sup-
port. This work was supported by grants from the Program of Pro-
moting Development for Guizhou, China (Qian-01-2005-01), the
XiBuZhiGuang Projects of CAS, the National Sciences of Yunnan,
China (2005C0010Z), the Knowledge Innovation Program of the
Chinese Academy of Sciences (KSCX2-YW-G-038), and the National
Natural Science Foundation of China (No. 30772636).
NMR spectra were recorded at 400 and 500 MHz using CDCl3 as
the solvent and chemical shifts were referenced to internal solvent
peaks. All melting points were measured with X-4 apparatus,
uncorrected. Optical rotations were recorded at Horiba SEAP-300
spectropolarimeter. IR spectra were recorded Shimadzu IR-450
instrument, in cmꢀ1, KBr pellets. FAB-MS and HRMS were recorded
at VG-AUTOSPEC-3000 spectrometer; in m/z (rel. int.% of the base
peak). Silica gel (200–300 mesh, Qingdao Marine Chemical, China)
was used for column chromatography (CC). Fractions were moni-
tored by TLC, and spots were visualized by heating TLC plates
sprayed with 10% H2SO4. All materials were obtained from com-
mercial suppliers and used without further purification.
Supplementary data
Supplementary data (experimental procedures and character-
ization of compounds 1–13, activity results and docking study)
associated with this article can be found, in the online version, at
4.2. Chemistry
References and notes
All the compounds (1–13) were prepared from Hup A by Schiff
reaction with benzaldehyde and cinnamaldehyde derivatives, see
Scheme 1, detailed method and spectroscopic data see Supplemen-
tary data.
1. Hebert, L. E.; Scherr, P. A.; Bienias, J. L.; Bennett, D. A.; Evans, D. A. Arch. Neurol.
2003, 60, 1119.
2. Lahiri, D. K.; Lewis, S.; Farlow, M. R. J. Neurosci. Res. 1994, 37, 777.
3. Kawakami, Y.; Inoue, A.; Kawai, T.; Wakita, M.; Sugimoto, H.; Hopfinger, A. J.
Bioorg. Med. Chem. 1996, 4, 1429.
4.3. Bioactivity test
4. Enz, A.; Boddeke, H.; Gray, J.; Spiegel, R. Ann. N.Y. Acad. Sci. 1991, 640, 272.
5. Marco-Contelles, J.; Carreiras, M. D. C.; Rodriguez, C.; Villarroya, M.; Garcia, A.
G. Chem. Rev. 2006, 106, 116.
6. Bai, D. L.; Tang, X. C.; He, X. C. Curr. Med. Chem. 2000, 7, 355.
7. Wang, R.; Yan, H.; Tang, X. C. Acta Pharmacol. Sin. 2006, 27, 1.
8. Qian, L. G.; Ji, R. Y. Tetrahedron Lett. 1989, 30, 208.
9. Xia, Y.; Kozikowski, A. P. J. Am. Chem. Soc. 1989, 111, 4116.
10. Kozikowski, A. P.; Xia, Y.; Reddy, E. R.; Tuckmantel, W.; Hanin, I.; Tang, X. C. J.
Org. Chem. 1991, 56, 4636.
11. Campiani, G.; Sun, L. Q.; Kozikowski, A. P.; Aagaard, P.; McKinney, M. A. J. Org.
Chem. 1993, 58, 7660.
12. Ma, X. Q.; Gang, D. R. Phytochemistry 2008, 69, 2022.
13. Kozikowski, A. P.; Campiani, G.; Sun, L. Q.; Wang, S. M.; Saxena, A.; Doctor, B. P.
J. Am. Chem. Soc. 1996, 118, 11357.
14. Kozikowski, A. P.; Miller, C. P.; Yamada, F.; Pang, Y. P.; Miller, J. H.; McKinney,
M.; Ball, R. G. J. Med. Chem. 1991, 34, 3399.
15. Xia, Y.; Reddy, E. R.; Kozikowski, A. P. Tetrahedron Lett. 1989, 30, 3291.
16. Campiani, G.; Kozikowski, A. P.; Wang, S.; Ming, L.; Nacci, V.; Saxena, A.;
Doctor, B. P. Bioorg. Med. Chem. Lett. 1998, 8, 1413.
17. Rajendran, V.; Prakash, K. R.; Ved, H. S.; Saxena, A.; Doctor, B. P.; Kozikowski, A.
P. Bioorg. Med. Chem. Lett. 2000, 10, 2467.
18. Rajendran, V.; Rong, S. B.; Saxena, A.; Doctor, B. P.; Kozikowski, A. P.
To determine the potential interest of compounds 1–13 for the
treatment of AD, their AChE inhibitory activity were assayed by the
method of Ellman. Five different concentrations of each compound
were used in order to obtain inhibition of AChE activity comprised
between 20% and 90%. The assay solution consisted of a 0.1 M
phosphate buffer pH 8.0, with the addition of 340
bis (2-nitrobenzoic acid), 0.02 unit/mL of TcAChE, hAChE, and
hBChE (Sigma Chemical), and 550 M of substrate (acetylthiocho-
line iodide or butyrylthiocholine iodide). Test compounds were
added to the assay solution and pre-incubated at 37 °C with the en-
zyme for 20 min followed by the addition of substrate. Assays were
done with a blank containing all components except AChE in order
to account for non-enzymatic reaction. The reaction rates were
compared and the percent inhibition due to the presence of test
compounds was calculated. Each concentration was analyzed in
triplicate, and IC50 values were determined graphically from log
concentration–inhibition curves.
l
M 5,50-dithio-
l
Tetrahedron Lett. 2001, 42, 5359.
19. Zhu, D.; Tang, X.; Lin, J.; Zhu, C.; Shen, J.; Wu, G.; Jiang, S.; Yamaguchi, T.;
Tanaka, K. PCT Int Appl WO 9911625.
20. Li, C.; Du, F.; Yu, C.; Xu, X.; Zheng, J.; Xu, F.; Zhu, D. Rapid Commun. Mass
Spectrom. 2004, 18, 651.
21. Raves, M. L.; Harel, M.; Pang, Y. P.; Silman, I.; Kozikowski, A. P.; Sussman, J. L.
Nat. Struct. Biol. 1997, 4, 57.
4.4. Molecular modeling methods
22. Haviv, H.; Wong, D. M.; Greenblatt, H. M.; Carlier, P. R.; Pang, Y. P.; Silman, I.;
Sussman, J. L. J. Am. Chem. Soc. 2005, 127, 11029.
23. Dvir, H.; Wong, D. M.; Harel, M.; Barril, X.; Orozco, M.; Luque, F. J.; Munoz-
Torrero, D.; Camps, P.; Rosenberry, T. L.; Silman, I.; Sussman, J. L. Biochemistry
2002, 41, 2970.
24. Kryger, G.; Silman, I.; Sussman, J. L. Structure 1999, 7, 297.
25. Greenblatt, H. M.; Guillou, C.; Guenard, D.; Badet, B.; Thal, C.; Silman, I.;
Sussman, J. L. J. Am. Chem. Soc. 2004, 126, 15405.
26. Pang, Y. P.; Quiram, P.; Jelacic, T.; Hong, F.; Brimijoin, S. J. Biol. Chem. 1996, 271,
23646.
27. Jin, G. Y.; Luo, X. M.; He, X. C.; Jiang, H. L.; Zhang, H. Y.; Bai, D. L. Arzneim.-Forsch.
2003, 53, 753.
28. Feng, S.; Wang, Z. F.; He, X. C.; Zheng, S. X.; Xia, Y.; Jiang, H. L.; Tang, X. C.; Bai,
D. L. J. Med. Chem. 2005, 48, 655.
29. Carlier, P. R.; Du, D. M.; Han, Y.; Liu, J.; Pang, Y. P. Bioorg. Med. Chem. Lett. 1999,
9, 2335.
30. Roman, S.; Badia, A.; Camps, P.; Clos, M. V. Neuropharmacology 2004, 46, 95.
All the molecular modeling studies were carried out using the
molecular docking software GOLD 3.1 running on PC with AS4. In or-
der to learn the interaction mode between Hup A derivatives and
AChE, molecular docking simulations were carried out with the
program GOLD 3.1 which used a genetic algorithm to explore the full
range of ligand conformational flexibility with partial flexibility of
protein. The structure of TcAChE and the Hup A analogues were
built using the SYBYL 7.1 molecular modeling software. The original
ligand and water were removed from the coordinated set of the
AChE (PDB ID: 1VOT). The following default genetic algorithm
parameters were used: 100 population sizes, 1.1 for selection, 5
number of islands, 100,000 number of genetic operations and 2
for the niche size. The ligand-based was created at the center of