Summary of organic chemistry doctoral thesis: Design, synthesis and evaluation of acetylcholinesterase inhibitory activity of chalcone derivatives for the discovery of new anti-alzheimer

MINISTRY OF EDUCATION
AND TRAINING

VIETNAM ACADEMY OF
SCIENCE AND TECHNOLOGY

GRADUATE UNIVERSITY SCIENCE AND
TECHNOLOGY

----------------------------TP Hồ Chí Minh - Năm 2017
Nguyen Thi Cam Vi

DESIGN, SYNTHESIS AND EVALUATION OF
ACETYLCHOLINESTERASE INHIBITORY ACTIVITY
OF CHALCONE DERIVATIVES FOR THE DISCOVERY
OF NEW ANTI-ALZHEIMER DRUGS

Major: Organic chemistry
Code: 9.44.01.14

SUMMARY OF ORGANIC CHEMISTRY DOCTORAL
THESIS

Ho Chi Minh – 2018


The doctoral thesis was finished at: Graduate University Science and

Công trình được hoàn thành tại Viện Công Nghệ Hóa Học
Technology - Vietnam Academy of Science and Technology.

Viện Khoa Học và Công Nghệ Việt Nam

The 1sthướng
supevisor:
Prof. Dr. Tran Thanh Dao
Người
dẫnAssoc.
khoa học

1.The
PGS.
TRẦN Assoc.
THÀNH
ĐẠO
2ndTS.
supevisor:
Prof.
Dr. Thai Khac Minh
2. PGS. TS. THÁI KHẮC MINH
The 1st doctoral thesis reviewer: …

Phản biện 1: TS. Nguyễn Thụy Việt Phương
The 2nd doctoral thesis reviewer: …

The 3rd doctoral thesis reviewer: ….

Phản biện 2: GS. TS. Phan Thanh Sơn Nam

The doctoral thesis will be protected at the evaluation coucil of PhD
dissertation (Academy degree), meeted at Graduate University

Science and Technology - Vietnam Academy of Science and
Luận
án sẽ được bảo vệ trước Hội đồng đánh giá luận án
Technology,
… Viện
am (pm),
dayNghệ
… month
yearViện
201….
cấp cơ sở họpattại
Công
Hóa…Học,
Khoa Học
và Công Nghệ Việt Nam.

Vào hồi……….. giờ ………… ngày ………. tháng ……….
năm 2017
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- Graduate University Science and Technology Library
- National Library of Vietnam

INTRODUCTION
1. The urgency of the thesis
Alzheimer’s disease (AD), the most common cause of dementia
in the elderly, is affecting millions of people worldwide. The ailment
is characterized by a complex neurodegenerative process occurring
in the central nervous system which leads to progressive cognitive
decline and memory loss. [1] The etiology of AD is not fully known,
although factors including the low levels of acetylcholine (ACh),
accumulation of abnormal proteins namely -amyloid and -protein,
homeostasis irregularity of biometals, and oxidative stress are
considered to play significant roles in the pathophysiology of AD.[2]
At the present , clinical therapy for AD patients is primarily
established upon the cholinergic hypothesis which suggests that the
decline of the ACh level might lead to cognitive and memory
deficits, and drugs with the ability of inhibiting acetylcholinesterase
(AChE) would control symptoms of the disease.[1]
Chalcone is a sub-group of flavonoid and is the intermediary in
the synthesis process of other flavonoids, pyrazoline, isoxazole, and
quinolinylpyrimidine. There are a lot of chalcone compounds which
are reported to have a diverse array of bioactivities such as
antibacterial, antifungal, antiviral, antioxidant, antitumoral, and other
characteristics such as anti-inflammatory, analgesic, antiulce. Recent
studies on the bioactivities of chalcone compounds have also
revealed their abilities in inhibiting enzymes including urease, glucosidase, lipoxygenase, acetylcholinesterase, mammalian alphaamylase, xanthine oxidase58, monoamine oxidase (MAO), and secretase. In addition, it was reported that chalcone derivatives
exhibit high binding affinity to A aggregates in vitro, and they

1

could serve as a useful mean for in vivo imaging of A plaques in
Alzheimer’s brain.[2-4] The studies on bioactivities of chalcone
derivatives on the function of human brain promise the finding of
new drugs for the treatment of many diseases including AD.
From the above scientific bases, the research project "Design,
synthesis and acetylcholinesterase inhibitory activity evaluation of
chalcone derivatives for the discovery of new anti-alzheimer drugs"
was conducted.
2. The objectives of the thesis
Molecular docking studies on acetylcholinesterase were performed to
predict the chalcone structure has good in silico AChE
acetylcholinesterase inhibitory activity. The potential chalcone
compounds were synthesized and studied for their in vitro and in
vivo AChE inhibitory activities.
3 . The main contents of the thesis
- The molecular binding abilities of chalcone derivatives with ACHE
were elucidated by docking procedure to predict the chalcone
structure has good in silico AChE acetylcholinesterase inhibitory
activity.
- The potential chalcone compounds were synthesized and studied
for their in vitro and in vivo AChE inhibitory activities.
Chapter 1. OVERVIEW
1.1. Alzheimer disease
Alzheimer’s disease (AD), the most common cause of dementia
in the elderly, is affecting millions of people worldwide. The ailment
is characterized by a complex neurodegenerative process occurring

2

in the central nervous system which leads to progressive cognitive
decline and memory loss. [1] The etiology of AD is not fully known,
although factors including the low levels of acetylcholine,
accumulation of abnormal proteins namely -amyloid and -protein,
homeostasis irregularity of biometals, and oxidative stress are
considered to play significant roles in the pathophysiology of AD.[12]
At the present , clinical therapy for AD patients is primarily
established upon the cholinergic hypothesis which suggests that the
decline of the ACh level might lead to cognitive and memory
deficits, and drugs with the ability of inhibiting acetylcholinesterase
(AChE) would control symptoms of the disease.[1]
1.2. Acetylcholinesterase (AChE)
Acetylcholinesterase (acetycholine acetylhydrolase, E.C. 3.1.1.7) [11]
is involved in the hydrolysis of acetylcholine, an essential
neurotransmitter of the central nervous system, into choline. This
enzyme catalyzes the hydrolysis of the neurotransmitter
acetylcholine at neuronal synapses, and at neuromuscular junctions,
at the end of the signaling process. In certain neurological disorders
such as Alzheimer’s disease, acetylcholinesterase is overactivated in
the synapses so that levels of acetylcholine in the brains is
significantly diminished, which leads to weakened neurotransmission
and thereby memory loss and other adverse effects.
1.3. Chalcone
Chalcones (1,3-diphenyl-2-propen-1-one) are open chain flavonoids
with a 15-carbon structure arranged in a C6-C3-C6 configuration.
They consist in two phenolic rings (A and B rings) connected by a
3C bridge with a double bond between α- and β-positions, which
confers them a particularly singular structure.[16]

3

Figure 1.7. Structure and numbering of chalcone
1.4. Molecular Docking
Molecular docking is an attractive scaffold to understand
drugbiomolecular interactions for the rational drug design and
discovery, as well as in the mechanistic study by placing a molecule
(ligand) into the preferred binding site of the target specific region of
the DNA/protein (receptor) mainly in a non-covalent fashion to form
a stable complex of potential efficacy and more specificity. The
information obtained from the docking technique can be used to
suggest the binding energy, free energy and stability of complexes.
At present, docking technique is utilized to predict the tentative
binding parameters of ligand-receptor complex beforehand.[21]
1.5. In vitro screening for acetylcholinesterase inhibition
AChE inhibitory activity was determined spectrophotometrically
using the Ellman's colorimetric method. ACHE hydrolyzes the
substrate ATCI to thiocholine and acetic acid. Thiocholine is allowed
to react with DTNB, and this reaction resulted in the development of
a yellow color. The color intensity of the product is measured at 405
nm, and it is proportional to the enzyme activity.[27]
1.6. Short-term memory impairment models
Loss of memory is among the first symptoms reported by patients
suffering from Alzheimer's disease (AD) and by their caretakers.

4


Currently, short-term memory impairment models are widely used in
the treatment of AD.[27]

The Y-maze model and Novel Object Recognition model are quick
and useful initial tests to study short-term memory.
Chapter 2. CONDITION AND EXPERIMENTAL METHOD
2.1. Time and place of study
Time: 1 11 2011 01/05/2017
Place: Labs of Department of Pharmacology, Department of
Pharmaceutical, Department of Microbiology, Faculty of Pharmacy,
Ho Chi Minh City Medicine and Pharmacy University.
2.2. Experimental content and method
2.2.1. Experimental content
The molecular binding abilities of chalcone derivatives with ACHE
were elucidated by docking procedure to predict the chalcone
structure has strong in silico AChE acetylcholinesterase inhibitory
activity. The potential chalcone compounds were synthesized by
Claisen-Schmidt condensation reaction. These chalcone compounds
are studied for their in vitro and in vivo AChE inhibitory activities.
2.2.2. Experimental method
Molecular Docking Study
The Protein Data Bank crystallographic structure of TcAChE(-)Galantamine complex (pdb 1DX6)67 was used as receptor model in
this study. The 3D structure of the crystallographic complex was
rendered by means of BioSolveIT LeadIt. The active site was defined
as all the important amino acid residues enclosed within a radius
sphere of 6.5 Å centered by the bound ligand, galantamine. All
unbound water molecules were eliminated and the structures of

5


amino acid residues were checked before re-establishing the active
site of the enzyme.

Docking process of 107 chalcone derivatives (35 normal chalcone
derivatives, 24 heterocyclic chalcone
derivatives, 32
benzylaminochalcone derivatives and 16 promazine chalcone
derivatives) was performed in BioSolveIT LeadIt with the following
options: the method in which base fragment placed in binding pocket
was Triangle Matching; the maximum number of solutions per
iteration was set to 1 000; the maximum number of solutions per
fragmentation was set to 200; the number of poses to keep for further
analysis of interaction was set to 10. The best conformation is the
one that has the most minus docking score. This score was the total
energy emitted from the formation of binding between the molecules
and the active site.
General Procedures for the Preparation of chalcone derivatives
Claisen-Schmidt condensation reaction was applied to synthesize
chalcone derivatives (Scheme 2.1). The reaction of acetophenone and
benzaldehyde derivatives in KOH/MeOH was followed by an
acidification with concentrated HCl provided chalcone derivatives
with satisfactory yields after recrystallized from appropriate solvents.
The structures and purities of the target compounds were confirmed by
UV, MS, IR, 1H-NMR and 13C-NMR spectra.

Scheme 2.1. Claisen-Schmidt condensation reaction in chalcones
synthesis[18]

6


In vitro Acetylcholinesterase inhibitory activity assay
AChE inhibitory activities of chalcones were determined using

purified acetylcolinesterase from electric eel (Sigma, Type VI) and
acetylthiocholine iodide (Sigma) as a substrate with the colourimetric
method of Ellman66. Galantamine, ATCI (acetylthiocholin iodide),
and DTNB (5,5’-dithio-bis-nitro benzoic acid) were purchased from
Sigma. This assay was performed in 96-well microtiter plates in the
same condition for both chalcones and control substance
(galantamine).
In vivo Acetylcholinesterase inhibitory activity assay
The best ACHE inhibitory chalcone derivative is tested for their
ability to improve memory dysfunction in mice using two short-term
memory impairment models: Y - maze model and Novel Object
Recognition model based on Tran Phi Hoang Yen model (2007).[28]
Chapter 3. RESULTS AND DISCUSSION
3.1. Molecular Docking Study
3.1.1. Re-docking result of co-crystallized ligand
Re-docking results of galantamine showed that interactions made
by re-docked conformations with the active site were resemble those
of the original bound ligand in 1DX6. The RMSD values of redocked conformations were < 1.5 Å (Table 3.1) indicated that the
molecular model could be applied to explain the interactions of new
ligands with the active site.

7


Table 3.1. Results of re-docking processes with co-crystallized
ligands
Ligand
RMSD (Å)
(1) separated from the complex (native form, not
0,4912

prepared).
(2) separated from the complex and re-prepared using
0,5184
mentioned appropriate procedure.
(3) built and prepared from the beginning.
0,5021
3.1.2 Docking results of chalcone derivatives
3.1.2.1 Docking results of 35 normal chalcone derivatives
The docking process was performed successfully with all
chalcone derivatives. The ways of change which are beneficial for
the binding ability to acetylcholinesterase of chalcones are
summarized and displayed in Fig 3.5.

Fig 3.5. The ways of change which are beneficial for the binding
ability to acetylcholinesterase of chalcones

8


The molecular docking studies elucidated the binding modes
of chalcones to the active site of AChE quite precisely, and from
which a structure – activity relationship was then drawn out.
Thenceforward, we have the direction to design and synthesize new
compounds that have high acetylcholinesterase inhibitory activities.
3.1.2.2. Docking results of 24 heterocyclic chalcone derivatives
The docking results showed that chalcones containing
thiophen moiety may increase the acetylcholinesterase inhibitory
activity compaire with other heterochalcone. Beside, the substitution
methoxy group(s) on B-ring (benzen ring) also lead to improve the
bioactivity of the heterochalcone.

X: thiophen moiety
-OCH3

more beneficial than

groups

pyridin, furan
moiety.

Hình 3.11. The ways of change which are beneficial for the binding
ability to acetylcholinesterase of heterocyclic chalcones
This study was published in "Evaluation of
acetylcholinesterase inhibitory activity of heterochalcones
derivaties" in Journal of Medicine, Ho Chi Minh city, 2015.
3.1.2.3 Docking results of 32 benzylaminochalcone derivatives
The docking process was performed successfully with all
benzylaminochalcone derivatives. The ways of change which are
beneficial for the binding ability to acetylcholinesterase of
benzylaminochalcone derivatives are summarized and displayed in
Fig 3.8.

9


- OH at position 2 or 3

N or O
heterocyclic

-OCH3 or -NO2 group on
- OH (necessary for a
high activity)

ring B affect the binding

g tốt

orientation to the target.

Fig 3.18. The ways of change which are beneficial for the binding
ability to acetylcholinesterase of benzylamino chalcones
From the docking results as fig 3.18, we have the direction to
design and synthesize new benzylamino chalcones that have high
acetylcholinesterase inhibitory activities.
3.1.2.4. Docking results of promazine chalcone derivatives
Promazine chalcones are chalcone derivatives that ring A is replaced
acepromazine. The docking process was performed with 16
promazine chalcone derivatives by BioSovelIT LeadIT.
The ways of change which are beneficial for the binding ability to
acetylcholinesterase of promazine chalcone derivatives are
summarized and displayed in Fig 3.22.

10


-Cl group

-OCH3 group

-Br group
-F group which have -Cl at
position ortho
Fig 3.22. The ways of change which are beneficial for the binding
ability to acetylcholinesterase of promazine chalcone derivatives
3.2. Synthesis of chalcone derivatives
3.2.1. Synthesis of normal chalcone derivatives
20 Normal chalcone derivatives based on the orientation of
docking results are synthesized by Claisen-Schmidt condensation
reaction.
Yield
DerivativesName of derivatives
(%)
ST1
(E)-2-chloro-2’-hydroxychalcone
68
ST2
(E)-4-chloro-2’-hydroxychalcone
74
ST3
(E)-2,4-dichloro-2’-hydroxychalcone
74
ST4
(E)-2,3-dichloro-2’-hydroxychalcone
67
ST5
(E)-2’-hydroxy-2,4-dimethoxychalcone
71
ST6
(E)-2’-hydroxy-2,3-dimethoxychalcone

48
ST7
(E)-2’-hydroxy-3,4,5-trimethoxychalcone
67
ST8
(E)-2’-hydroxy-4-dimethylaminochalcone
87
ST9
(E)-2’-hydroxy-2,3,4’-trimethoxychalcone
58
ST10 (E)-2’-hydroxy-3,4,4’-trimethoxychalcone
62

11


ST11
ST12
ST13
ST14

(E)-2’-hydroxy-3,4,4’,5-tetramethoxychalcone
63
(E)-4-chloro-2’-hydroxy-4’-methoxychalcone
68
(E)-2’-hydroxy-2,4,4’,6’-tetramethoxychalcone
55
(E)-2’-hydroxy-3,4,4’,6’-tetramethoxychalcone
66
(E)-2’-hydroxy-2,3,4,4’,6’ST15

72
pentamethoxychalcone
(E)-4-chloro-2’-hydroxy-4’,6’ST16
69
dimethoxychalcone
ST17 (E)-4’-amino-2-chlorochalcone
66
ST18 (E)-4’-amino-4-chlorochalcone
70
ST19 (E)-4’-amino-4-nitrochalcone
76
ST20 (E)-3’,4-dinitrochalcone
60
Structure of all synthesized chalcone derivatives were
confirmed by UV, IR, 1H-NMR spectra and showed in addendum 6.
3.2.2. Synthesis of heterocyclic chalcone derivatives
24 heterocyclic chalcone derivatives are synthesized by ClaisenSchmidt condensation reaction.
Yield
DerivativesName of derivatives
(%)
(E)-1-(pyridin-2-yl)-3-[2-(hydroxy)phenyl]-2D1
56
propen-1-one
(E)-1-(pyridin-2-yl)-3-[4-(hydroxy)phenyl]-2D2
65
propen-1-one
(E)-1-(pyridin-2-yl)-3-[3-(hydroxy)phenyl]-2D3
62
propen-1-one
(E)-1-(pyridin-2-yl)-3-[4D4

58
(dimethylamino)phenyl]-2-propen-1-one
(E)-1-(pyridin-2-yl)-3-[3,4-(dimethoxy)phenyl]-2D5
52
propen-1-one
(E)-1-(pyridin-2-yl)-3-[3,4,5-(trimethoxy)phenyl]D6
76
2-propen-1-one

12


D7
D8
D9
D10
D11
D12
D13
D14
D15
D16
D17
D18
D19
D20
D21
D22
D23

(E)-1-(pyridin-2-yl)-3-[2,4-(dimethoxy)phenyl]-2propen-1-one
(E)-1-(furan-2-yl)-3-[3,4-(dimethoxy)phenyl]-2propen-1-one
(E)-1-(furan-2-yl)-3-[4-(methoxy)phenyl]-2propen-1-one
(E)-1-(furan-2-yl)-3-[3,4,5-(trimethoxy)phenyl]-2propen-1-one
(E)-1-(furan-2-yl)-3-[4-(hydroxy)phenyl]-2propen-1-one
(E)-1-(furan-2-yl)-3-[3-(hydroxy)phenyl]-2propen-1-one
(E)-1-(furan-2-yl)-3-[2-(hydroxy)phenyl]-2propen-1-one
(E)-1-(furan-2-yl)-3-[3-(nitro)phenyl]-2-propen-1one
(E)-1-(furan-2-yl)-3-[4-(dimethylamino)phenyl]2-propen-1-one
(E)-1-(thiophen-2-yl)-3-[4-(hydroxy)phenyl]-2propen-1-one
(E)-1-(thiophen-2-yl)-3-[3-(hydroxy)phenyl]-2propen-1-one
(E)-1-(thiophen-2-yl)-3-[2-(hydroxy)phenyl]-2propen-1-one
(E)-1-(thiophen-2-yl)-3-[4-(methoxy)phenyl]-2propen-1-one
(E)-1-(thiophen-2-yl)-3-[2,4-(dimethoxy)phenyl]2-propen-1-one
(E)-1-(thiophen-2-yl)-3-[3,4,5(trimethoxy)phenyl]-2-propen-1-one
(E)-1-(thiophen-2-yl)-3-[3-(nitro)phenyl]-2propen-1-one
(E)-1-(thiophen-2-yl)-3-[3-(nitro)phenyl]-2propen-1-one

13

63
51
64
68
50
54
52
54
62
56

52
54
66
52
74
52
56


D24

(E)-1-(thiophen-2-yl)-3-[4(dimethylamino)phenyl]-2-propen-1-one

60

3.2.3. Synthesis of benzylaminochalcone derivatives
The Claisen-Schmidt condensation reaction of 4'aminoacetophenone and benzaldehyde derivatives provided 10
benzylaminochalcones.
Yield
DerivativesName of derivatives
(%)
(E)-1-(4-((2-hydroxylbenzyl)amino)phenyl)-3A1
80,88
phenyl)prop-2-ene-1-one
(E)-3-(2-chlorophenyl)-1-(4-((2A2
88
hydroxylbenzyl)amino)phenyl)prop-2-ene-1-one
(E)-3-(4-chlorophenyl)-1-(4-((2A3
81,60
hydroxylbenzyl)amino)phenyl)prop-2-ene-1-one

(E)-3-(4-nitrophenyl)-1-(4-((2A4
60
hydroxylbenzyl)amino)phenyl)prop-2-ene-1-one
(E)-3-(2,3-dimethoxyphenyl)-1-(4-((2A5
81,51
hydroxylbenzyl)amino)phenyl)prop-2-ene-1-one
(E)-3-(3,4-dimethoxyphenyl)-1-(4-((2A6
58,85
hydroxylbenzyl)amino)phenyl)prop-2-ene-1-one
(E)-3-(2,4-dimethoxyphenyl)-1-(4-((2A7
80
hydroxylbenzyl)amino)phenyl)prop-2-ene-1-one
(E)-1-(4-((2-hydroxylbenzyl)amino)phenyl)-3A8
82,71
(pyridin-2-yl)prop-2-ene-1-one
(E)-1-(4-((2-hydroxylbenzyl)amino)phenyl)-3A9
69,23
(pyridin-4-yl)prop-2-ene-1-one
(E)-3-(furan-2-yl)-1-(4-((2A10
76,30
hydroxylbenzyl)amino)phenyl)prop-2-ene-1-one

14


10
Benzylaminochalcone were recognised as new
compounds based on Scifinder (2016). This study was published in
"Synthesis of novel chalcones as acetylcholinesterase inhibitors" in
Applied Sciences, 2016.[44]

3.2.4. Synthesis of promazine chalcone derivatives
10 promazine chalcones (AC1-AC10) based on the
orientation of the docking results are synthesized by Claisen-Schmidt
condensation reaction.
Yield
DerivativesName of derivatives
(%)
(E)-3-(2-chlorophenyl)-1-(10-(3AC1 (dimethylamino)propyl)-10H-phenothiazin-2-yl)- 81%
3-phenylprop-2-en-1-one
(E)-3-(4-chlorophenyl)-1-(10-(3AC2 (dimethylamino)propyl)-10H-phenothiazin-2-yl)- 78%
3-phenylprop-2-en-1-one
(Z)-3-(2,4-dichlorophenyl)-1-(10-(3AC3 (dimethylamino)propyl)-10H-phenothiazin-2-yl)- 62%
3-phenylprop-2-en-1-one
(E)-1-(10-(3-(dimethylamino)propyl)-10HAC4 phenothiazin-2-yl)-3-(4-fluorophenyl)prop-2-en-1- 57%
one
(E)-3-(3-bromophenyl)-1-(10-(3AC5 (dimethylamino)propyl)-10H-phenothiazin-2-yl)- 51%
3-phenylprop-2-en-1-one
(E)-3-(2-chloro-6-fluorophenyl)-1-(10-(3AC6 (dimethylamino)propyl)-10H-phenothiazin-2-yl)- 43%
3-phenylprop-2-en-1-one
(E)-1-(10-(3-(dimethylamino)propyl)-10HAC7
58%
phenothiazin-2-yl)-3-(2-

15


trifluoromethyl)phenyl)prop-2-en-1-one
(E)-1-(10-(3-(dimethylamino)propyl)-10HAC8 phenothiazin-2-yl)-3-(3-methoxyphenyl)prop-2en-1-one
(E)-1-(10-(3-(dimethylamino)propyl)-10HAC9 phenothiazin-2-yl)-3-(4-methoxyphenyl)prop-2en-1-one
(E)-1-(10-(3-(dimethylamino)propyl)-10HAC10 phenothiazin-2-yl)-3-(3,4,5trimethoxyphenyl)prop-2-en-1-one

9 Promazine chalcones (AC1-AC8 and AC10)
recognised as new compounds based on Scifinder (2017).

43%

41%

51%
were

3.3. In vitro Acetylcholinesterase inhibitory activity assay
3.3.1. In vitro Acetylcholinesterase inhibitory activity assay of
normal chalcone derivatives
The IC50 values of 20 normal chalcone derivatives for AChE
inhibition are indicated in Table 3.13.
Bảng 3.13. The IC50 values (%) of 20 normal chalcone derivatives
for AChE inhibition
Derivatives

IC50
(µM)

ST1
ST2
ST3
ST4
ST5

92,42
52,71

51,01
62,37
86,45

Docking
score
(kJ/mol)
-27,33
-34,46
-29,98
-23,47
-26,43

Derivatives IC50 (µM)
ST11
ST12
ST13
ST14
ST15

16

> 500
> 500
349,09
> 500
> 500

Docking
score

(kJ/mol)
-19,41
-19,41
-20,27
-15,40
-18,37


ST6
ST7
ST8
ST9
ST10

> 500
-16,50
ST16
213,14
-20,54
> 500
-17,50
ST17
36,10
-36,29
> 500
-18,30
ST18
> 500
-14,53
190,98

-24,28
ST19
> 500
-19,41
129,90
-25,90
ST20
> 500
-21,25
There was a good correlation between docking scores and
bioactivities of studied chalcone compounds. Among the studied
compounds, S17 showed the strongest interaction with its target.

Hình 3.35. 2D interactions between S17 and the active site of AChE
(pdb id: 1dX6)
4.3.2 In vitro Acetylcholinesterase inhibitory activity assay of
heterocyclic chalcone derivatives
The results showed that heterocyclic chalcones containing
thiophen moiety may increase the acetylcholinesterase inhibitory
activity compaire with other heterochalcone. Among the studied
heterocyclic chalcones, D21 containing thiophen moiety and 3 OCH3 groups has the best IC50 (114,8 µM). This study was published
in "Evaluation of acetylcholinesterase inhibitory activity of
heterochalcones derivaties" in Journal of Medicine, Ho Chi Minh

17


city, 2015.[43]
4.2.3 Khảo sát khả năng kháng acetylcholinesterase của các dẫn
chất benzylaminochalcone

The IC50 values of 10 benzylaminochalcone derivatives
for AChE inhibition are indicated in Table 3.18.
Table 3.18. The IC50 values of 10 benzylaminochalcone derivatives
for AChE inhibition
Derivatives IC50 (µM) pIC50
Docking score (kJ/mol)
A1
160.33
-2.21
−18.23
A2
121.91
-2.09
−20.34
A3
23.71
-1.37
−20.55
A4
31.57
-1.50
−21.89
A5
121.61
-2.08
−20.56
A6
23.02
-1.36
−19.32

A7
147.84
-2.17
−18.34
A8
116.34
-2.07
−20.07
A9
38.97
-1.59
−21.42
A10
89.19
-1.95
−21.22
Galantamine
1.27
0.10
−23.1
Compounds with ring B bearing pyridin-4-yl, 4-nitrophenyl,
4-chlorophenyl and 3,4-dimethoxyphenyl moieties were discovered
to
exhibit
significant
inhibitory
activities
against
acetylcholinesterase, with IC50 values ranging from 23 to 39 µM.
Among

of
them,
(E)-3-(3,4-dimethoxyphenyl)-1-(4-((2hydroxylbenzyl)amino) phenyl)prop-2-ene-1-one (A6) has a
strongest bioactivity as acetyl-cholinesterase inhibitors (IC50 23,02
µM). This result was published in "Synthesis of novel chalcones as
acetylcholinesterase inhibitors" in Applied Sciences, 2016.[44]

18


3.3.4 In vitro Acetylcholinesterase inhibitory activity assay of
promazine chalcone derivatives
The IC50 values of 10 promazine chalcone derivatives for
AChE inhibition are indicated in Table 3.19.
Table 3.19. Giá trị IC50 của 10 promazine chalcone đối với AChE
Derivatives IC50 (µM) pIC50
Docking score (kJ/mol)
AC1
-1.56
-22,072
35.96
AC2
160.35
-2.21
-18,455
AC3
50.21
-1.70
-21,271
AC4

90.09
-1.95
-18,926
AC5
-1.39
-24,261
24.39
AC6
40.37
-1.61
-21,891
AC7
347.34
-2.54
-17,721
AC8
93.10
-1.97
-20,026
AC9
-1.53
-22,567
33.50
AC10
120.64
-2.08
not
Galantamine
1,27
0,10

-23,1
Compounds with ring B bearing 3-bromophenyl (AC5), 2chlorophenyl (AC1) and 4-methoxyphenyl (AC9 were discovered to
exhibit significant inhibitory activities against acetylcholinesterase,
with IC50 values ranging from 24,39 to 35,96 µM. Among of them,
(E)-3-(3-bromophenyl)-1-(10-(3-(dimethylamino)propyl)-10Hphenothiazin-2-yl)-3-phenylprop-2-en-1-on (AC5 has a strongest
bioactivity as acetyl-cholinesterase inhibitors (IC50 24,39 µM).
3.4 In vivo Acetylcholinesterase inhibitory activity assay of
benzylaminochalcone A6
The best ACHE inhibitory chalcone derivative (A6) is tested
for their ability to improve memory dysfunction in mice using two

19


short-term memory impairment models: Y - maze model and Novel
Object Recognition model. The mice received three dose of A6
derivative: 20 mg/kg, 15 mg/kg and 10 mg/kg three days before the
intraperitoneal (i.p) injection of 2.4 mg/kg trimethyltin (TMT); and
three days later, the mice were tested on the models. Results on both
models showed that A6 derivative dose 15 mg/kg could improve
memory impairment in mice similar to galanthamine dose 10,0
mg/kg.
This result was published in "Experimental antioxidant and
memory-improving property of benzylaminochalcon in mice" in
Pharmaceutical journal, 2017.[47]
CONCLUSION
The new results of the thesis "Design, synthesis and
acetylcholinesterase inhibitory activity evaluation of chalcone
derivatives for the discovery of new anti-alzheimer drugs" are
indicated as followings:

1. The molecular binding abilities of 107 chalcone
derivatives (35 normal chalcone derivatives, 24 heterocyclic
chalcone derivatives, 32 benzylaminochalcone derivatives and 16
promazine chalcone derivatives) with ACHE were elucidated by
docking procedure to predict the chalcone structure has strong in
silico AChE acetylcholinesterase inhibitory activity.
2. By applying Claisen-Schmidt condensation method, 64
chalcone derivatives (20 normal chalcone derivatives, 24
heterocyclic chalcone
derivatives, 10 benzylaminochalcone
derivatives and 10 promazine chalcone derivatives) based on the
orientation of the docking results were synthesized sucessfully with
yield ranging from 40 to 88 %. Among of them, 10

20


benzylaminochalcone derivatives and 9 promazine chalcone
derivatives were recognised as new compounds.
3. Invitro AChE inhibitory activities of synthesized chalcones
were determined. There was a good correlation between docking
scores and bioactivities of studied chalcone compounds.
Benzylaminochalcones with ring B bearing 3,4-dimethoxyphenyl
(A6), 4 - chlorophenyl (A3) and promazine chalcone with ring B
bearing 3-bromophenyl (AC5) were discovered to exhibit significant
inhibitory activities against acetylcholinesterase, with IC50 values
ranging from 23,02 to 24,39 µM.
4. The best AChE inhibitory chalcone derivative (A6) is
tested for their ability to improve memory dysfunction in mice using
two short-term memory impairment models: Y - maze model and

Novel Object Recognition model. A6 derivative dose 15 mg/kg
could improve memory impairment in mice similar to galanthamine
dose 10,0 mg/kg.
The discovered results may be regarded as efficient
candidates for further developments of new anti-alzheimer drugs.
NEW FINDINGS OF THE THESIS
- The molecular binding abilities of chalcone derivatives with ACHE
were elucidated by docking procedure to predict the chalcone
structure has good in silico AChE acetylcholinesterase inhibitory
activity. This result supported to synthesize chalcone derivatives
more effectively and economically.
- 64 chalcone derivativess were synthesized and studied for their in
vitro AChE inhibitory activities. Among of them, 10
benzylaminochalcone derivatives and 9 promazine chalcone
derivatives were recognised as new compounds.

21


- Many new chalcone derivatives were discovered to exhibit
significant inhibitory activities against acetylcholinesterase, with
IC50 < 50 µM.
- Experimental memory-improving property of benzylaminochalcon
A6 discovered that A6 derivative dose 15 mg/kg could improve
memory impairment in mice similar to galanthamine dose 10,0
mg/kg.
LIST OF WORKS HAS BEEN PUBLISHED
1. Thanh-Dao Tran, Thi-Cam-Vi Nguyen, Ngoc-Son Nguyen, DaiMinh Nguyen, Thi-Thu-Ha Nguyen, Minh-Tri Le, and Khac-Minh
Thai, Synthesis of novel chalcones as acetylcholinesterase inhibitors,
Applied Sciences, 2016, 6(7), 198.

2. Thanh-Dao Tran, Thai-Son Tran, Thi-Cam-Vi Nguyen, Minh-Tri
Le and Khac-Minh Thai, Synthesis, In vitro Acetylcholinesterase
Inhibitory Activity Evaluation and Docking Investigation of Some
Aromatic Chalcones, MedPharmRes, 2017, Volume 1, Issue 1.
3. Nguyen Thi Cam Vi, Trinh Quynh Dieu,Tran Phi Hoang Yen,Thai
Khac Minh, Tran Thanh Dao, Experimental antioxidant and
memory-improving property of benzylaminochalcon in mice,
Pharmaceutical journal, 2017, 494, 17-21.
4. Minh Dai Nguyen, Vi Thi Cam Nguyen, Dat Van Truong, Ha
Tuong Do and Dao Thanh Tran, Synthesis and cytotoxic activities of
some heterocyclic chalcones, The 19th International Electronic
Conference on Synthetic Organic Chemistry, 2015.
5. Nguyen Thi Cam Vi, Tran Thi Kieu Diem, Tran Thanh Dao,
Evaluation of acetylcholinesterase inhibitory activity of
heterochalcones derivaties, Journal of Medicine, 2015, 19(3), 744750.

22


6. Nguyen Thi Cam Vi, Mai Hoang Yen, Tran Thanh Dao,
Evaluation of acetylcholinesterase inhibitory activity of isoflavone
derivatives by molecular docking model, Journal of Medicine, 2015,
19(3), 751-760.
7. Tran Hong Thoai Nga, Nguyen Thi Cam Vi, Tran Cat Dong, Tran
Thanh Dao, Investigation of antimicrobial activities of some
combinations of heterocyclic chalcone and antibiotic against
samonella and shigella, Journal of Medicine, 2011, 15, 431-437.
8. Tran Thi Kim Thoa, Do Tuong Ha, Nguyen Thi Cam Vi, Tran Cat
Dong, Tran Thanh Dao, Effects on methicillin-resistant
Staphylococcus aureus of flavonoids separately and in combination

with ciprofloxacin, Pharmaceutical journal, 2011, 417, 24-30.

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