Exploring coumarin potentialities: Development of new enzymatic inhibitors based on the 6-methyl-3-carboxamidocoumarin scaffold

Article abstract of DOI:10.1039/c6ra05262b

Novel 6-methyl-3-carboxamidocoumarins (compounds 4-15) were synthesized by an effective three step synthetic strategy and screened towards MAO, AChE and BuChE enzymes. In general, the compounds act as selective MAO-B inhibitors. Compound 11 is highlighted as a potent (IC₅₀hMAO-B = 4.66 nM), reversible and non-competitive MAO-B inhibitor.

Full text of DOI:10.1039/c6ra05262b

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Exploring coumarin potentialities: development of new enzymatic
inhibitors based on the 6-methyl-3-carboxamidocoumarin scaffold
A. Fonsecaa,b, M. J. Matosa, J. Reisa, Y. Duartec, M. Gutiérrezc, L. Santanab, E. Uriarteb and F.
Borges*a
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
Novel 6-methyl-3-carboxamidocoumarins (compounds 4-15) were their low content in endogenous antioxidants, such as
synthesized by an effective three step synthetic strategy and glutathione, (b) the high proportion of an easily oxidized
screened towards MAO, AChE and BuChE enzymes. In general, the membrane covered by polyunsaturated fatty acids (c) the
compounds act as selective MAO-B inhibitors. Compound 11 is great oxygen brain consumption and also (d) a high content in
highlighted as a potent (IC50 hMAO-B = 4.66 nM), reversible and iron.7–9 In addition, concerning AD, MAO-B activity and the
non-competitive MAO-B inhibitor.
coproduction of H2O2 and other type of ROS are also
increased, leading to an amplification of the neuron oxidative
stress damage process. The current therapy for PD is only
palliative and is focused in curtailing the motor symptoms by
restoring the dopamine levels, namely by the administration of
L-dopa, a dopamine precursor, alongside with other drug co-
adjuvants, such as dopamine agonists, catechol-o-
methyltransferase (COMT) and MAO-B inhibitors, such as
selegiline. For AD, the therapy is only focused on the
administration of acetylcholinesterase (AChE) inhibitors that
target the cholinergic system, considering that the disease is
characterized by a cholinergic neuronal loss, and consequently
acetylcholine (ACh) depletion.10 In brain synapses, ACh is
hydrolyzed by AChE into choline and acetate.11 At present
The increase in average life expectancy in developed countries
has led to a rise of diagnosed cases of neurodegenerative
diseases (ND’s), namely Parkinson’s (PD) and Alzheimer’s (AD)
diseases,1,2 and dementia. Currently none of these illnesses
have an effective treatment to modify or stop their progress.
The drugs currently available are only useful for delay the
progress of the diseases by controlling their symptoms.2,3
Monoamine oxidases (MAOs) are enzymes present in the
outer mitochondrial membrane, which have two isoforms
named as MAO-A and MAO-B that catalyze the oxidation of
biogenic amines.4 Neurotransmitters, such as adrenaline,
noradrenaline, dopamine, serotonin and β-phenylethylamine,
are the main MAO substrates. Under normal conditions
noradrenaline and serotonin are substrates of MAO-A while
dopamine, a neurotransmitter present in low concentrations in
the PD patients brain, has a greater affinity for MAO-B.5
Activity of MAO-B is also linked to the production of reactive
oxygen species (ROS) that cause oxidative stress and neuronal
damage. Expression levels of MAO-B in neuronal tissue
augment 4-fold with aging, resulting in an increased of
dopamine metabolism and therefore, higher production of
hydrogen peroxide (H2O2).6 Thus, MAO-B inhibitors play an
important role not only in dopamine metabolism but also in
the reduction of brain oxidative damage. The involvement of
MAO-B in AD is supported by the fact that neurons are
extremely sensitive to oxidative stress as a consequence of: (a)
butyrylcholinesterase (BuChE) was also proposed as
a
druggable target and as a result both enzymes represent
putative therapeutic targets for improving the cholinergic
deficit responsible for the decline in cognitive, behavioral and
global functioning characteristic of AD.12,13 Like in PD, none of
the current drugs in therapy are able to modify disease
progression, a condition that is well thought-out to be a driving
force behind the ongoing research related to the discovery of
new and potent inhibitors based on different types of
scaffolds.14
Coumarins are heterocycles widely found in plants and other
natural products that have synthetic accessibility and display
remarkable biological properties, such as anticancer, antiviral,
anti- inflammatory, antimicrobial and antioxidant agents.15–29
Previous studies have shown that coumarin is a noteworthy
scaffold for the discovery and development of new potent and
selective MAO-B and AChE inhibitors.25
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methylcoumarin (IC50 hMAO-B = 170 nM), which did not have
relevant AChE inhibitory activity.
So, additional studies focused in the effect of a carboxamide
linker, located between coumarin and the exocyclic aromatic
substituent, were accomplished. Within this framework new 6-
methyl-3-carboxamidocoumarins (compounds 4-15, Figure 1)
were designed, synthesized and studied as MAO enzymatic
inhibitors.
Coumarin derivatives (
a three step synthetic strategy described in Scheme
explained in detail in supplementary material. Briefly, in the
first step the coumarin used as starting material (compound
was synthesized by a Knoevenagel condensation, in which 5-
methylsalicylaldehyde ( ) was refluxed with diethyl malonate
in ethanol, in presence of catalytic amounts of piperidine.
After subsequent hydrolysis, compound was obtained with
an overall yield of 89%.31 Then, compounds
15 were
synthesized by an amidation reaction in which the carboxylic
acid was activated with a coupling agent 1-ethyl-3-(3-
dimethylaminopropyl)carbodiimide (EDC) in the presence of a
4
-
15) have been obtained efficiently by
1
and
2)
1
3
Figure 1 - Rational design followed in the present study to obtain the 3-substituted
4-
coumarins 4-15.
3
Coumarins previously developed by our group (Figure
1,
structure A) have shown to display a remarkable potency and nucleophilic catalyst 4-dimethylaminopyridine (DMAP).32 After
selectivity towards MAO-B activity. Till now our best-in-class adding the primary aromatic amine with the desired
coumarin IMAO-B was 3-(3-bromophenyl)-6-methylcoumarin substitution
(IC50 hMAO-B = 134 pM).30 The data attained so far stimulate derivatives (
pattern,
6-methyl-3-carboxamidocoumarin
4-15) have been obtained with yields ranging from
the progress of the project and in accordance a lead- 56% to 83%. Structural characterization of the compounds was
optimization process was implemented in which the effect of a performed by 1H and 13C NMR spectroscopy, mass
linker, located between the coumarin core and the exocyclic spectrometry (EI-MS) and elemental analysis and is included in
aromatic ring, in IMAO activity was studied. In addition, and supplementary material. The biological evaluation of the
taking advantage of the expenditure of the project it was also compounds
4-15 towards hMAO-A and hMAO-B was
decided to move on from one-target to a dual-target drug investigated by measuring their effects on the production of
design approach. So, other targets of interest in H2O2 from p-tyramine (a MAO substrate), using the Amplex
neurodegenerative diseases, like AChE, have been involved. Red MAO assay kit and recombinant hMAO with selegiline as
The first studies were focused on the role of carbonylamine reference compound.33 In addition, the inhibitory activities of
type linker (Figure 1, structure B). From the study, potent and the compounds 4-15 were evaluated towards Electrophorus
selective IMAO-B were attained which were also able to inhibit electricus AChE and bovine serum BuChE using Ellman
AChE in the range from 12 µM to 69 µM.29 The best dual spectrophotometric method and galantamine as reference
candidate of the series was 3-(4’-chlorobenzamide)coumarin compound.34 The biological activity results expressed as IC50
(IC50 hMAO-B = 1.95 µM and IC50 AChE = 18.71 µM). The best values are listed in Table 1.
IMAO-B of the series was 3-(4‘-methylbenzamide)-6-
2 | J. Name., 2012, 00, 1-3
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Scheme 1 - Synthesis of coumarins 4-15.Reagents and conditions: a) diethyl malonate, EtOH, piperidine, reflux, overnight. b) NaOH (0.5% aq./EtOH), reflux, 4h. c) EDC, DMAP,
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DCM, corresponding amine, 0 ºC to r.t., 4h.

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Table 1. In vitro hMAO-A, hMAO-B and AChE inhibitory activities of 6-methyl-3-carboxamidocoumarin derivatives (4-15) and reference compounds.
Compound
IC50 (nM) hMAO-A
IC50 (nM) hMAO-B
11.80 ± 1.10
7.52 ± 1.05
SI
IC50 (µM) AChE
a
>847.4b
>1329.8b
>719.4 b
>62.3 b
c
4
a
a
a
a
a
a
a
a
a
a
a
5
535.24 ± 0.01
657.22 ± 0.01
494.45 ± 0.03
6
13.90 ± 1.30
160.60 ± 1.10
10.10 ± 1.20
296.90 ± 5.90
13.50 ± 1.10
4.66 ± 1.13
7
>990.0 b
>33.7 b
470.52 ± 0.18
8
c
9
>740.7 b
>2145.9b
>877.2 b
>546.4 b
>220.3 b
>16.1 b
621.23 ± 0.07
591.44 ± 0.02
358.88 ± 0.05
10
11
12
13
11.40 ± 1.20
18.30 ± 1.60
45.40 ± 1.30
621.70 ± 1.80
666.37 ± 0.11
c
14
c
15
d
17.00 ± 1.903
Selegiline
Galantamine
68730 ± 420
4042.9
d
d
d
0.54 ± 0.50
a Inactive at 10 µM (highest concentration tested) b Values obtained under the assumption that the corresponding IC50 against MAO-A is the highest
concentration tested (10 µM) c Inactive at 1000 µM (highest concentration tested) d Not determined
In general, compounds
towards MAO-B, as they were inactive against
highest concentration tested, and an interesting structure- remained almost constant at different concentrations of the
dependent inhibitory potency. The methyl ( ) and bromine inhibitor whereas Vmax decreased. The Lineweaver-Burk plots
10 12) derivatives, bearing substituents located at ortho obtained for different concentrations of compound 11 (Figure
meta and para positions of the exocyclic aromatic ring, exhibit ) displayed a series of converging lines on the same point of
MAO-B activity in the low nanomolar range. In the case of the the x-axis (1/[S]) profiling non-competitive inhibition
methoxy substituted coumarins (compounds ), only the mechanism. From the Dixon plots, obtained from the replots
meta-substituted derivative display potency in the same range. of the slopes of the Lineweaver–Burk plots vs inhibitor
For the hydroxy coumarin derivatives (compounds 13 15), it concentrations (upper right corner), the MAO-B inhibition
4-
15 display a remarkable selectivity parameters (Michaelis constant, Km and maximum velocity,
h
h
MAO-A at the Vmax). Concerning compound 11, it was found that the Km
4-6
(
-
,
2
a
7-9
-
h
can be concluded that the MAO-B inhibitory activity is strongly binding affinities, determined as inhibition constants (Ki), were
dependent on the substituent location, being enhanced when calculated. As a result, compound 11 (Figure 2) displayed a Ki
they are located at ortho and meta positions. In summary, it value of 2.70 nM. The estimated Ki value correlated well with
was observed that the presence of electron donor substituents the inhibition mechanism suggested by the kinetic
in the para position of the aryl ring attached to the amide experiments, with the compound displaying IC50 and Ki values
group lead to a potency decrease, whereas derivatives bearing slightly different but within the low nanomolar range.
weak electron donors or acceptors do not change IMAO-B
potency independently of their position. The 6-methyl-3-
carboxamidocoumarins substituted in the meta position
(compounds
MAO-B than their ortho (compounds
(compounds and 12 counterparts. In particular,
compounds MAO-B = 7.52 nM) and 11 (IC50 MAO-B =
4.66 nM) showed MAO-B inhibition at a low nanomolar
5,
8
and 11) have a superior activity towards
4, 7
and 10) and para
6,
9
)
5
(IC50
h
h
h
range, slightly better than selegiline, and also benefiting from
an excellent selective profile.
To examine the type of inhibition mechanism of the most
promising
experiments were performed. For this purpose, the initial rates
of the MAO-B-catalyzed oxidation of -tyramine at five
h
MAO-B inhibitor (compound 11
)
kinetic
Figure 2 - Kinetic study on the mechanism of hMAO-B inhibition by compound 11. The
effect of the inhibitors on the enzyme was determined from the double reciprocal plot of
1/rate (1/V) versus 1/substrate concentration in presence of varying concentrations of the
inhibitors. The Ki value was calculated by the intersection of the curves obtained by
plotting 1/V versus the inhibitor concentration for each substrate concentration (Dixon
plots insets on the top right).
p
different substrate concentrations, in the absence or presence
of the selected coumarin inhibitor, at different concentrations,
were measured. The results are depicted in Figure 2.
Graphical analyses of the reciprocal Lineweaver−Burk plots
allow the determination of Michaelis−Menten reacꢀon kineꢀc
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The reversibility of MAO-B inhibition by the test compound 11 penetration was also calculated. The data are presented in
was then assessed by time-dependent inhibition studies. The Table . Complete procedures of in vitro biological studies,
2
behavior of standard irreversible (R-(-)-deprenyl) and statistical analysis and drug-like properties calculations are
reversible (safinamide) inhibitors was also evaluated under the listed in the supplementary material.
same experimental conditions. MAO-B activity (% of control) Analyzing the results for the inhibitory activity towards human
was measured along 60 minutes incubation with the enzyme AChE depicted in Table 1, one can conclude that all
inhibitors (Figure
inhibition studies performed with the irreversible inhibitor (R- (micromolar range) towards the enzyme. None of the tested
(-)-deprenyl, Figure ) showed that the enzyme residual compounds displayed a noticeable activity towards BuChE at
3). The analysis of time-dependent enzyme compounds presented
a
moderate inhibitory activity
3
activity decayed continuously after the first 15 minutes of the highest concentration tested (10 mM) (data not shown).
incubation, which is consistent with irreversible enzymatic Compound 12, the para-bromine coumarin derivative, was
inhibition. In case of the reversible inhibitor safinamide (Figure found to be the most active compound towards AChE (IC50 =
3), an enhancement on enzymatic activity was observed along 358.88 µM). Analysing the overall data, one can conclude that
the analysis time. A similar behavior was observed for the 6-methyl-3-carboxamidocoumarins substituted with
a
compound 11, which shows the gradual link to the allosteric hydroxyl substituent (compounds 13
binding site (non-competitive inhibitor) in the first 15 minutes, compounds of the series. However, when a methyl or methoxy
proceeded by the enhancement of enzymatic activity along the substituent (compounds and ) is located at meta position of
last 60 minutes, as its expectable of a MAO-B reversible the aromatic exocyclic ring a slight increment of inhibitory
inhibition profile. activity is observed, when compared with their ortho
-15) are the less potent
5
8
(compounds
counterparts.
4 and) and para (compounds 6 and 9)
Table 2. Drug-like properties of 6-methyl-3-carboxamidocoumarin derivatives (4-15) and reference compounds.
Compound
4 / 5 / 6
Molecular weight
293.3
cLogP
TPSA (Å2)
59.31
68.54
59.31
79.54
3.24
H-bond donor
H-bond acceptor
Volume (Å3)
264.5
3.66/ 3.68 / 3.71
3.27/ 3.29 / 3.31
4.02/ 4.04 / 4.07
2.99/ 2.75 / 2.78
2.64
4
5
4
5
1
4
1
1
1
2
0
1
7/ 8 / 9
309.3
273.5
10/ 11 / 12
13/ 14/ 15
Selegiline
Galantamine
358.2
265.8
295.3
256.0
187.3
202.6
287.4
1.54
41.93
268.2
In our previous study, compound
6
analogue (compound 4 in
ref.29), which also have a methyl substituent, in para position,
had displayed a IC50 MAO-B = 170 nM, which is ten times
h
lower. Nevertheless, it showed a superior affinity to AChE than
the compounds presented here.29 Thus, it can be concluded
that the carboxamide spacer, and specially the location of the
carbonyl group, is a key feature for MAO-B and AChE inhibitory
activities.
Additionally, from the prediction drug-like properties of
compounds 4-15 (Table 2) it can be observed that no violations
Figure 3
- Time-dependent inhibition of recombinant human MAO-B by standard
of Lipinski’s rule (molecular weight, logP, number of hydrogen
donors and acceptors) were found and that the TPSA,
described as a predictive indicator of the drug capacity of
membrane penetration, is favorable. Therefore, the data
provided a preliminary indication that this type of compounds
can cross membranes and act in the central nervous system.
compounds (R)-(−)-Deprenyl (50 nM), safinamide (40 nM) and test compound 11 (15
nM), The remaining activity was expressed as % of activity. Data are the mean ± S.D. of
three different experiments.
Finally, the drug-like properties of the compounds 4–15
,
namely the lipophilicity (expressed as the octanol/water
partition coefficient, and herein called clogP) and other
properties (molecular weight, number of hydrogen acceptors
and donors and volume) were calculated using the
Molinspiration calculation software. Topological polar surface
area (TPSA) that has been shown to be a very good descriptor
of drug absorption, including intestinal absorption,
bioavailability, Caco-2 permeability and blood–brain barrier
The remarkable results found for compounds 5 and 11 (hMAO-
B IC50 of 7.52 and 4.66 nM respectively) encourage us to
continue our research based on the coumarin scaffold.
Compound 11 acts as a potent, selective, reversible and non-
competitive MAO-B inhibitor. In addition, compound 12
(hMAO-B IC50 of 11.40 nM and AChE IC50 of 358.88 µM) can be
looked as a stimulating framework to develop dual target
MAO-B/AChE inhibitors. Further examination of the cytotoxic
4 | J. Name., 2012, 00, 1-3
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and pharmacokinetic properties of compounds 11 and 12 is
important to define if which of them will be a candidate for in
vivo studies. In summary, the data attained so far is a 23
noteworthy contribution for the development of new drug
candidates for PD and AD based on 6-methylcoumarin
Borges, S. Kachler and K. N. Klotz, J. Pharm. Pharmacol,
2013, 65, 697-703.
I. Kostova, S. Bhatia, P. Grigorov, S. Balkansky, V. S. Parmar,
A. K. Prasad and L. Saso, Curr. Med. Chem., 2011, 18, 3929–
3951.
scaffold.
24
M. J. Matos, P. Janeiro, R. M. González Franco, S. Vilar, N.
P. Tatonetti, L. Santana, E. Uriarte, F. Borges, J. A. Fontenla
and D. Viña, Future Med. Chem., 2014, 6, 371–383.
M. J. Matos, D. Viña, E. Quezada, C. Picciau, G. Delogu, F.
Orallo, L. Santana and E. Uriarte, Bioorg. Med. Chem. Lett.,
2009, 19, 3268–3270.
Notes and references
25
1
2
3
R. J. Castellani, R. K. Rolston and M. a. Smith, Disease-a-
26
27
M. J. Matos, D. Viña, C. Picciau, F. Orallo, L. Santana and E.
Uriarte, Bioorg. Med. Chem. Lett., 2009, 19, 5053-5055.
M. J. Matos, S. Vazquez-Rodriguez, L. Santana, E. Uriarte, C.
Fuentes-Edfuf, Y. Santos and A. Muñoz-Crego, Molecules,
2013, 18, 1394–1404.
Month, 2010, 56, 484–546.
L. M. L. de Lau and M. M. B. Breteler, Lancet. Neurol., 2006,
5, 525–535.
M. R. Farlow and J. L. Cummings, Am. J. Med., 2007, 120,
388–397.
28
29
30
M. J. Matos, C. Terán, Y. Pérez-Castillo, E. Uriarte, L.
Santana and D. Viña, J. Med. Chem., 2011, 54, 7127–7137.
D. Viña, M. J. Matos, M. Yáñez, L. Santana and E. Uriarte,
Med. Chem. Commun., 2012, 3, 213–218.
4
5
J. P. Johnson, Biochem. Pharmacol., 1968, 17, 1285–1297.
M. B. Youdim, D. Edmondson and K. F. Tipton, Nat Rev
Neurosci., 2006, 7, 295–309.
6
A. Gaspar, N. Milhazes, L. Santana, E. Uriarte, F. Borges and
M. J. Matos, Curr. Top. Med. Chem., 2015, 15, 432–445.
P. Riederer, Neurotoxicology, 2004, 25, 271–277.
V. Jain, M. C. Langham and F. W. Wehrli, J. Cereb. Blood
Flow Metab., 2010, 30, 1598–1607.
M. J. Matos, S. Vilar, V. Garcia-Morales, N. P. Tatonetti, E.
Uriarte, L. Santana and D. Viña, ChemMedChem, 2014, 9,
1488–1500.
7
8
31
32
F. Chimenti, B. Bizzarri, A. Bolasco, D. Secci, P. Chimenti, A.
Granese, S. Carradori, D. Rivanera, A. Zicari, M. Scaltrito,
and F. Sisto, Bioorg. Med. Chem. Lett. 2010, 20, 4922–
4926.
9
T. A. Rouault, Nat Rev Neurosci., 2013, 14, 551–564.
M. Itakura, H. Nakajima, T. Kubo, Y. Semi, S. Kume, S.
Higashida, A. Kaneshige, M. Kuwamura, N. Harada, A. Kita,
Y.-T. Azuma, R. Yamaji, T. Inui and T. Takeuchi, J. Biol.
Chem., 2015, jbc.M115.669291.
10
C. Murata, T. Masuda, Y. Kamochi, K. Todoroki, H. Yoshida,
H. Nohta, M. Yamaguchi and A. Takadate, Chem. Pharm.
Bull. (Tokyo). 2005, 53, 750–758.
11
12
V. N. Talesa, Mech. Ageing Dev., 2001, 122, 1961–1969.
M. Khoobi, M. Alipour, A. Moradi, A. Sakhteman, H. Nadri,
S. F. Razavi, M. Ghandi, A. Foroumadi and A. Shafiee, Eur. J.
Med. Chem., 2013, 68, 291–300.
33
34
M. Yáñez, N. Fraiz, E. Cano and F. Orallo, Biochem. Biophys.
Res. Commun. 2006, 344, 688–695.
P. Torre, L. Saavedra, J. Caballero, J. Quiroga, J. Alzate-
Morales, M. Cabrera and J. Trilleras, Molecules 2012, 17,
12072–12085
13
14
15
16
17
R. M. Lane, S. G. Potkin and A. Enz, Int. J.
Neuropsychopharmacol., 2006, 9, 101–124.
M. Singh, M. Kaur, H. Kukreja, R. Chugh, O. Silakari and D.
Singh, Eur. J. Med. Chem., 2013, 70, 165–188.
F. Borges, F. Roleira, N. Milhazes, L. Santana and E. Uriarte,
Curr. Med. Chem., 2005, 12, 887–916.
F. Borges, F. M. F. Roleira, N. Milhazes, E. Uriarte and L.
Santana, Front. Med. Chem., 2009, 4, 23–85.
M. Riveiro, N. De Kimpe, A. Moglioni, R. Vazquez, F.
Monczor, C. Shayo and C. Davio, Curr. Med. Chem., 2010,
17, 1325–1338.
18
19
20
21
22
M. J. Matos, S. Vazquez-Rodriguez, L. Santana, E. Uriarte, C.
Fuentes-Edfuf, Y. Santos and A. Munoz-Crego, Med. Chem.
(Los. Angeles)., 2012, 8, 1140–1145.
D. Viña, M. J. Matos, G. Ferino, E. Cadoni, R. Laguna, F.
Borges, E. Uriarte and L. Santana, ChemMedChem, 2012, 7,
464–470.
M. J. Matos, S. Vazquez-Rodriguez, E. Uriarte, L. Santana
and D. Viña, Bioorg. Med. Chem. Lett., 2011, 21, 4224–
4227.
D. Secci, S. Carradori, A. Bolasco, P. Chimenti, M. Yáñez, F.
Ortuso and S. Alcaro, Eur. J. Med. Chem., 2011, 46, 4846–
4852.
S. Vazquez-Rodriguez, M. J. Matos, L. Santana, E. Uriarte, F.
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