Novel Sustainable-by-Design HDAC Inhibitors for the Treatment of Alzheimer's Disease

Article abstract of DOI:10.1021/acsmedchemlett.9b00071

Alzheimer's disease (AD) represents a global problem, with an estimation of the majority of dementia patients in low- and middle-income countries by 2050. Thus, the development of sustainable drugs has attracted much attention in recent years. In light of this, taking inspiration from the HDAC inhibitor vorinostat (1), we develop the first HDAC inhibitors derived from cashew nut shell liquid (CNSL), an inexpensive agro-food waste material. CNSL derivatives 8 and 9 display a HDAC inhibitory profile similar to 1, together with a more promising safety for 9 compared to 1. Moreover, both compounds and particularly 9 were able to effectively modulate glial cell-induced inflammation and to revert the pro-inflammatory phenotype. All these results demonstrate that the use of inexpensive food waste materials could be successfully applied for the development of accessible and sustainable drug candidates for the treatment of AD.

Full text of DOI:10.1021/acsmedchemlett.9b00071

Subscriber access provided by UNIV OF NEW ENGLAND ARMIDALE
Letter
Novel sustainable-by-design HDAC inhibitors
for the treatment of Alzheimer’s disease
Luiz A. S. Romeiro, Jessica L. d. C. Nunes, Camila d. O. Miranda, Gabriella Simões
Heyn Roth Cardoso, Andressa de Oliveira, Annachiara Gandini, Tereza Kobrlova, Ondrej
Soukup, Michele Rossi, Johanna Senger, Manfred Jung, Silvia Gervasoni, Giulio Vistoli,
Sabrina Petralla, Francesca Massenzio, Barbara Monti, and Maria Laura Bolognesi
ACS Med. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acsmedchemlett.9b00071 • Publication Date (Web): 29 Mar 2019
Downloaded from http://pubs.acs.org on March 30, 2019
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 7
ACS Medicinal Chemistry Letters
1
2
3
4
5
6
7
8
9
Novel sustainable-by-design HDAC inhibitors for the treatment of
Alzheimer’s disease
Luiz Antonio Soares Romeiro,*(a, b) Jéssica Larissa da Costa Nunes,(a) Camila de Oliveira Miranda,(a)
Gabriella Simões Heyn Roth Cardoso,(a) Andressa Souza de Oliveira,(a) Annachiara Gandini,(c, d) Tereza
Kobrlova(e), Ondrej Soukup,(e) Michele Rossi,(c) Johanna Senger,(f) Manfred Jung,(f) Silvia Gervasoni,(g)
Giulio Vistoli,(g) Sabrina Petralla,(c) Francesca Massenzio,(c) Barbara Monti,(c) Maria Laura Bolognesi*(c)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(a) Department of Pharmacy, Health Sciences Faculty, University of Brasília, Campus Universitário Darcy Ribeiro, 70910-
900, Brasília, DF, Brazil; (b) LADETER, Catholic University of Brasilia, QS 07, Lote 01, EPCT, Águas Claras, 71966-700,
Brasília, DF, Brazil; (c) Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Via
Belmeloro 6, I-40126 Bologna, Italy; (d) Department of Neuroscience, Laboratory of Prion Biology, Scuola Internazionale
Superiore di Studi Avanzati (SISSA), Via Bonomea 265, I-34136 Trieste, Italy; (e) Biomedical Research Center, University
Hospital Hradec Kralove, 500 00, Hradec Kralove, Czech Republic; (f) Institute of Pharmaceutical Sciences, University of
Freiburg, Albertstraße 25, 79104 Freiburg im Breisgau, Germany; (g) Department of Pharmaceutical Science, University of
Milan, Via Mangiagalli 25, 20133, Milan, Italy.
KEYWORDS Neurodegenerative drug discovery, sustainable drugs, immunomodulation, food waste.
ABSTRACT: Alzheimer’s disease (AD) represents a global problem, with an estimation of the majority of dementia patients in low-
and middle-income countries by 2050. Thus, the development of sustainable drugs has attracted much attention in recent years. In
light of this, taking inspiration from the HDAC inhibitor vorinostat (1), we develop the first HDAC inhibitors derived from cashew
nut shell liquid (CNSL), an inexpensive agro-food waste material. CNSL derivatives 8 and 9 display a HDAC inhibitory profile
similar to 1, together with a more promising safety for 9 compared to 1. Moreover, both compounds and particularly 9, were able to
effectively modulate glial cell-induced inflammation, and to revert the pro-inflammatory phenotype. All these results demonstrate
that the use of inexpensive food waste materials could be successfully applied for the development of accessible and sustainable drug
candidates for the treatment of AD.
Alzheimer’s disease (AD) is the most common form of
dementia and a global health problem. In fact, if AD was
initially thought of as the epidemic of the developed world, with
its aging population, nowadays it particularly impacts low- and
middle-income countries.1
disease, the differential susceptibility and disease course in
males and females, as well as the late age onset and the
influence of lifestyles, highlight that genetic causes alone fail to
explain AD etiology, and reinforce the hypothesis that
epigenetic might play a key role.8, 9 Evolving lines of research
indicate that pharmacologically targeting epigenetic
There is no definitively established cause nor either a cure for
AD, with available treatments ultimately failing to modify
disease progression.2 In addition, if we want to guarantee
universal coverage and equity of access to treatments to the
global AD population, the medications must be affordable and
accessible to avoid overwhelming developing countries’ health
systems.3 This clearly adds lines of complexity to AD drug
discovery, which is already one of the most formidable
challenges for the pharmaceutical community.4 However, it is
something we must focus on, so as to ensure that we “leave no
one behind” in the battle for a cure.5
mechanisms,
namely
DNA
methylation,
histone
acetylation/deacetylation, or non-coding RNA, may be of
potential benefit in AD. Particularly, restoring the perturbed
acetylation homeostasis of the neurodegenerative state by
histone modification has become one of the most significant
research hot spots.10 Indeed, if epigenetic treatments represent
fewer than 2% of current drugs in Alzheimer’s trials,
Alzheimer’s Drug Discovery Foundation (ADDF) considers
this as an emerging area holding great promise.11 One of the two
epigenetic drugs currently in AD clinical trials is HDAC
inhibitor (HDACi) vorinostat (1, Figure 1), a drug approved for
the treatment of subcutaneous T cell lymphoma. Its therapeutic
potential in AD is based on in vivo animal studies suggesting
that its specific inhibition of class I histone deacetylases
(HDACs) and HDAC6 (class IIb), could be most beneficial in
treating dementia.12
In AD most cases occur in patient with no known family
history and are not linked to a genetic cause; thus, AD is mostly
sporadic. Mutations in specific genes can only explain 5-10%
of the cases.6 The genes implicated in early-onset familial AD
are those encoding for amyloid precursor protein (APP),
presenilin 1, and presenilin 2. The gene implicated in the
pathogenesis and the risk of developing sporadic AD is
apolipoprotein E ε4 (APOE ε4).7 The sporadic nature of the
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
generated complexes for 8 as obtained for HDAC1 (A) and
Page 2 of 7
1
HDAC6 (B).
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 3. Main interactions stabilizing the putative complexes as
computed for 8 within the binding pocket of HDAC1 (A) and
HDAC6 (B).
Figure 1. Chemical structures of HDACi 1 and CNSL derivatives
2-5.
In both complexes, the Zinc binding group shows the
expected bidentate chelation further stabilized by polar
interactions with His140 and Tyr303 (in HDAC1) as well as
with His610 and Tyr782 (in HDAC6). The carbon linker is
engaged in apolar contacts which appear to be richer in HDAC6
(with His611, Phe620, His651, Phe680 and Leu749) than in
HDAC1 (with Phe150, His178 and Leu271). Finally, the cap
moiety contacts the cavity rim where it can elicit  stacking
reinforced by a H-bond with His499 in HDAC6 and with
Tyr204 and Phe205 in HDAC1. The more hindered cap moiety
of 9 does not elicit relevant additional contacts but it might even
interferes with the rim residues, a feature more pronounced in
HDAC1 where it clashes against Pro29, due to the already
documented greater narrowness of the HDAC1 cavity rim
compared to HDAC6.20 Notably, both compounds compare
well with the corresponding complexes stabilized by 1. As
exemplified by Figure S1 for 8 within the HDAC6 binding site,
the linkers and the two hydroxamic groups show
superimposable binding modes. In contrast, the cap phenyl
groups show different arrangements reasonably due to the effect
of the amide function which induces a more folded arrangement
in the linker of 1. Based on these results, both compounds were
synthesized and biologically characterized.
With these concepts in mind and in conjunction with our
studies aimed to explore the potential of cashew nut shell liquid
(CNSL) for the production of AD drugs,13 herein we focused on
the development of 1’s derivatives obtained from an
inexpensive agro-food waste material. CNSL is a by-product of
the cashew kernel industry, extremely interesting in terms of
waste valorization for the production of new chemicals.14
Although one of its main components, i.e. anacardic acid (2a,
Figure 1),15 as well as some synthetic derivatives,16-18 are well-
known histone acetyltransferase inhibitors, to the best of our
knowledge no report has never addressed the possibility to
obtain AD-targeted HDACis from CNSL.
Design. We pursue the idea that CNSL is a valuable starting
point in the search for cost-effective and sustainable HDACis
against AD. Chemically, CNSL is a source of non-isoprenoid
lipids, mainly anacardic acids (2), cardanols (3), cardols (4), and
2-methylcardols (5) (Figure 1). All of them share a phenolic
structure, bearing a C15-alkyl side chain (with different degrees
of unsaturation) in meta-position with respect to the hydroxyl
group (see Figure 1).19
Chemistry. Hydroxamates 8 and 9 were prepared by
aminolysis exploiting the methyl esters 14 and 15 as starting
reagents. The required methyl 8-(3-methoxyphenyl)octanoate
(14)
and
methyl
8-(3-methoxy-2-
carbomethoxyphenyl)octanoate (15) were synthesized through
methylation of mixtures of unsaturated 2 and 3 isolated from
CNSL.13 Thus, individual reactions of 2 and 3 with
iodomethane in acetone afforded the corresponding O-
methoxycardanol 10 (92%) and methyl O-methoxyanacardate
11 (90%) mixtures. Next, treatment of 10 or 11 with ozone air
in dichloromethane/methanol (1:1) at -70° C, followed by
reduction with sodium borohydride furnished the corresponding
alcohols 12 (80%) or 13 (50%).
Scheme 1. Synthesis of hydroxamates 8 and 9.
Figure 2. Design of CNSL derivatives 8 and 9.
We were intrigued by the fact that the C8-acids 6 and 7
(Figure 2), easily obtained from CNSL by oxidative cleavage
derivatization, might be an optimal starting point for the
synthesis of hydroxamates inspired by 1. Particularly,
hydroxamates 8 and 9 (derived from 3 and 2) bear clear
chemical resemblance to 1, including the metal binding moiety,
the carbon linker, and the capping group. To this end, docking
simulations were carried out to confirm the proper fit of the
designed 8 and 9 at class I nuclear HDAC1 and HDAC6
isoforms, in comparison with 1. Figure 3 depicts the best
ACS Paragon Plus Environment

Page 3 of 7
ACS Medicinal Chemistry Letters
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 4. Percentages of inhibition of HDACs 1-11 by derivatives
8 (blue) and 9 (orange) at 10 μM.
Treatment of 12 or 13 with PCC led to the aldehydes
intermediates which were oxidized by Jones Reagent to the
acids 6 (96%) and 7 (70%). In turn, 6 and 7 were converted to
the respective methyl esters 14 (74%) and 15 (70%) by treating
with iodomethane in acetone. Despite its effectiveness, this
synthetic sequence is clearly not compatible with sustainability
criteria. In response to these concerns, greener methods for
producing 14 and 15 are being developed. Finally, 14 and 15
were converted into target hydroxamates 8 and 9 following
aminolysis with hydroxylamine generated in situ (Scheme 1).
From these data, we confirmed that the newly synthesized
derivatives 8 and 9 display a class I HDAC/HDAC6 selectivity
profile, very similar to 1. Once again, the close resemblance
among 8, 9 and 1 accounts for a similar HDAC selectivity.
BBB permeation studies. For AD-directed HDACis, the
capability to cross the blood-brain barrier (BBB) is a
fundamental pre-requisite. Nevertheless, recent studies have
revealed that several HDACis, potentially useful to study/treat
neurodegenerative diseases, show limited BBB permeation.24
For the prediction of 8 and 9 to passively penetrate the BBB a
Parallel Artificial Membrane Permeability Assay (PAMPA)
was used. Data obtained for 8 and 9, together with precursors
2a and 3a, were correlated to standard drugs, where CNS
bioavailability is known. The results showed in Table S1 clearly
demonstrate that 8 and 9 are predicted to cross the BBB by
passive diffusion as their Pe values are above those of the
standard AD drugs (tacrine, donepezil, and rivastigmine).
Moreover, the modifications performed improved the CNS
drug-like properties of natural 3a, for which passive brain
bioavailability is uncertain. Notably, 2a’s BBB penetration
estimation was not determined due to its low solubility in the
assay media.
HDAC biochemical assays. Considering that the most
promising HDACi for learning and memory indications exhibit
the greatest selectivity for class
I HDACs, targeted
development of class I HDAC isoforms has been advocated for
AD.21 In addition, although not fully elucidated, HDAC6 has
been suggested to play
a
role in AD-associated
neurodegeneration.22 Based on these considerations and on 1’s
class I HDAC/HDAC6 inhibitory profile, we preliminary
verified the computationally predicted capacity of 8 and 9 to
properly bind HDAC1 and HDAC6 through a biochemical
assay.23 1 and 6 were used as positive and negative controls,
respectively (Table 1). As expected, 1 modulated the activity of
HDAC1 and 6 with roughly equivalent submicromolar potency.
Both 8 and 9 exhibited a similar HDAC profile, with inhibitory
potencies that were only slightly decreased (by 2.7 to 6.5-fold
with respect to 1). Thus, the obtained results support the starting
idea that the insertion of the hydroxamate moiety on a CNSL
backbone provides SAHA-like HDACis. Indeed, acid 6, devoid
of the hydroxamate moiety, showed only a modest inhibition
(<15%) at 10 µM.
Neurotoxicity assays. 1 is an approved drug for the treatment
of cutaneous T cell lymphoma, but, intuitively, the use of
HDACis for non‐oncology indications requires more stringent
safety profiles.25 Thus, neurotoxicity of 1, 8 and 9, in
comparison with precursors 2a and 3a, was evaluated on
primary cultures of cerebellar granule neurons (CGNs), as a
useful in vitro model to study neuronal death.26 CGNs viability
was assessed after 24h treatment at three different
concentrations (5, 25, 50 μM) using the MTT (3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay
(Figure 5).
Table 1. In vitro inhibition of HDAC1 and HDAC6.
In spite of the prominent relevance of class I HDAC and
HDAC6 isoforms, the role of individual HDAC enzymes as
well as the action of specific HDACis in neurodegenerative
diseases remains far from clear.10 Thus, to preliminary address
selectivity of the sub-micromolar inhibitors 8 and 9, we profiled
them in single dose duplicate mode at a concentration of 10 μM
against HDACs 1-11 (Figure 4). Trichostatin A (TSA) was used
as reference compound.
Figure 5. Neurotoxicity of 1, 2a, 3a, 8, and 9 on primary rat CGNs
after 24 h treatment. Results are expressed as percentage of controls
and are the mean ± SE of at least three different experiments, each
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
Page 4 of 7
run in triplicate. ** p < 0.01 *** p < 0.001 compared to control
conditions.
microglial production of proinflammatory marker iNOS.
Importantly, at 5 µM, 8 and 9 were even more effective than
reference compound 1, by almost completely abolishing iNOS
expression. These results highlight the potential of both 8 and 9
to effectively modulate glial cell-induced inflammation, and to
be able, in principle, to revert the pro-inflammatory phenotype.
Then, we examined the capability of 1, 8, and 9, to promote M2
microglial phagocytosis, by evaluating MRC1 profile
expression (Figure 7). Positively, 1 does not affect MRC1
expression levels at the two tested concentrations, whereas 9
shows a positive outcome only at 25 µM. Conversely 8 displays
a dose-dependent negative effect. These findings suggest that
the M1/M2 immunomodulatory profile might not be directly
linked to the HDAC inhibitory activity, as indicated by the
strong induction of histone H3 acetylation in microglial cells
(Figure 6). Indeed, the transcriptional machinery responsible
for regulating the gene networks accounting for the two
activation states is complex and still not elucidated.
1
2
3
4
5
6
7
8
It is evident that 1 displays signs of neurotoxicity at the higher
tested concentrations (CGNs viability 70% at 25 µM, and 52%
at 50 µM). 8 affects neuronal viability even at 5 µM
concentration (CGNs viability ≤ 50%). A more suitable profile
is showed by 9 at all tested concentrations: CGNs viability >
80% even at 50 μM. Regarding the corresponding precursors,
3a shows a more promising safety profile compared to 2a, with
no evident signs of toxicity at the tested concentrations.
9
HDAC cellular assays. To confirm the HDAC biochemical
results at a neural cellular level, Western blotting experiments
to detect histone H3 acetylation were performed with 1, 8 and
9. As HDACis were reported to prevent the lipopolysaccharide
(LPS)-induced decrease of acetylated histones H3 in microglia
(but had no effect on the basal HDAC activity),27 LPS-treated
N9 microglial cells were incubated for 24 h with three different
concentrations (5, 10, and 25 μM) of the tested compounds. In
accordance with the HDAC enzymatic profiles, 8 and 9 are able
to induce H3 acetylation in a similar fashion to 1 (Figure 6).
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 6. Western blots of acetyl-H3, and total H3 after treatment
of N9 cells with 1, 8, and 9. Results are expressed as percentage of
controls and are the mean ± SE of three different experiments. * p
< 0.05 compared to control conditions.
Figure 7. Immunomodulatory effects of 1, 8, and 9 in microglial
cells evaluated through Western blot analysis of iNOS and MRC1
expression. GAPDH was used as loading control. Densitometric
results are expressed as percentage of LPS only and are the mean ±
SE of three independent experiments. * p < 0.05 ** p < 0.01
compared to LPS condition.
Immunomodulation assays. In neurology, HDACis have a
long history of clinical use as mood stabilizers and anti-
epileptics. More recently, 1 and other HDACis have attracted
attention for AD primarily on the basis of their promising anti-
neuroinflammatory profile.28 Microglia, as the immune cells of
the brain, are pivotal mediators of neuroinflammatory
processes. Microglial activation in the CNS is heterogeneous,
categorized into two opposite phenotypes: M1 and M2. M1
microglia, activated by LPS or IFN-γ, have pro-inflammatory,
neurotoxic properties, inducing the proliferation of lymphocyte.
Alternatively activated M2 microglia are able to repair small
damage, have an anti-inflammatory phenotype, contributing to
trophic support of neurons, to degradation of toxic aggregates,
and increase the neuroprotective functions thanks to anti-
inflammatory interleukins and growth factors production. M1
activation is associated with the expression of pro-
inflammatory molecules, like inducible Nitric Oxide Synthase
(iNOS). The M2 activation state is associated with the
production of anti-inflammatory cytokines and specific markers
of phagocytosis, such as Mannose Receptor type C 1 (MRC1).29
On this basis, immunomodulation strategies aiming to attenuate
M1 microglial activation or to trigger an M1/M2 microglial
shift may contribute to counteract, at least partially, cognitive
impairment in AD and other neurodegenerative diseases.30 To
this end, we tested whether our compounds could affect iNOS,
and triggering MRC1 profile expression upon inflammatory
stimuli with LPS (100 ng/mL) at 5 and 25 µM concentrations.
As reported in Figure 7, 1, 8, and 9, all suppressed the
Neuroprotective assays. In spite of the well-recognized
potential of HDAC inhibition against neurodegeneration,
increasing recent evidences suggest that inhibition of single
isoforms can results in both neuroprotective and
neurodegenerative effect.31 Although not yet elucidated, this
might depend on context-specific and tissue/cell-specific
effects. Taking this into account, we tested whether 1, 8, and 9
can protect CGNs from low serum- and K+-induced neuronal
death (Figure 8). Tacrine (1,2,3,4-tetrahydroacridin-9-amine),
the first FDA-approved AD drug, was used as reference
compound (Figure S2). Unfortunately, under these
experimental conditions, all the three HDACis were not able to
restore neuronal viability, with 6h pre-treatment followed by
24h co-treatment, although their effect is not so detrimental in
terms of reduction of viability. To note, 1 and 9 display a similar
profile.
ACS Paragon Plus Environment

Page 5 of 7
ACS Medicinal Chemistry Letters
Figure 8. Neuroprotective effects of 1, 8, and 9 on serum and K+
deprivation-induced neurotoxicity in CGNs. * p < 0.05 ** p < 0.01
ABBREVIATIONS
1
2
3
4
5
6
7
8
AD, Alzheimer’s disease; ADDF, Alzheimer’s Drug
Discovery Foundation; APOEε4, apolipoprotein E ε4; APP,
amyloid precursor protein; BBB, blood-brain barrier; CGNs,
cerebellar granule neurons; CNSL, cashew nut shell liquid;
HDACi, histone deacetylases inhibitor; HDACs, histone
deacetylases; iNOS, inducible Nitric Oxide Synthase; LPS,
lipopolysaccharide; MRC1, Mannose Receptor type C 1;
PAMPA, Parallel Artificial Membrane Permeability Assay;
TSA, Trichostatin A.
#
##
*** p < 0.001 compared to control conditions; p < 0.05, p <
0.01 compared to serum and K+ deprivation conditions.
Conclusions. In conclusion, we were successful to discover
8 and 9 as the first HDACis derived from the inexpensive CNSL
raw material. Although clinical translation of HDACis in AD
remains elusive, in our hands, they (particularly 9) displayed a
therapeutic potential similar to that of AD investigational drug
1. At the same time, they might have an improved potential in
terms of sustainability and less toxicity in some cases. As a
starting material for the synthesis of new drugs, CNSL presents
clear advantages from economical and ethical perspectives,
compared to both synthetic and natural chemicals:32 (1)
abundant volumes are available in those countries (Brazil and
India) which still are and will be main actors in the AD global
scenario; (2) it is an inedible raw material not depleting natural
resources; (3) it is a food waste-product amenable to waste
valorization. All these considerations, point to the use of food
waste-products as an enlightening perspective towards more
accessible and sustainable drugs to the global AD community
patients.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
REFERENCES
1.
World Alzheimer report 2015 - the global impact of
dementia: an analysis of prevalence, incidence, cost and trends.
https://www.alz.co.uk/research/world-report-2015 (accessed March
2019)
2.
Cummings, J.; Lee, G.; Ritter, A.; Zhong, K. Alzheimer's
disease drug development pipeline: 2018. Alzheimer's & Dementia:
Translational Research & Clinical Interventions 2018, 4, 195-214.
3.
countries. In Rev Neuropsiquiatr, 2017; Vol. 80, pp 105-109.
4. Cummings, J. L.; Morstorf, T.; Zhong, K. Alzheimer's
Marciani, D. J. Facing Alzheimer’s disease in the developing
disease drug-development pipeline: few candidates, frequent failures.
Alzheimers Res. Ther. 2014, 6, 37.
ASSOCIATED CONTENT
Supporting Information
5.
Prince, M. Progress on dementia - leaving no one behind.
The Lancet 390, e51-e53.
6.
Bekris, L. M.; Yu, C.-E.; Bird, T. D.; Tsuang, D. W.
Genetics of Alzheimer disease. J. Geriatr. Psychiatry Neurol. 2010, 23,
213-227.
The Supporting Information is available free of charge on the ACS
Publications website.
7.
Hori, Y.; Hashimoto, T.; Nomoto, H.; Hyman, B. T.;
Iwatsubo, T. Role of Apolipoprotein E in beta-Amyloidogenesis:
isoform-specific effects on protofibril to fibril conversion of Abeta in
vitro and brain Abeta deposition in vivo. J. Biol. Chem. 2015, 290,
15163-15174.
Figures S1 and S2, Table S1, experimental details for chemistry
and biological assays, spectral copies of 1H NMR and 13C NMR of
compounds 8 and 9 (PDF).
8.
Chouliaras, L.; Rutten, B. P.; Kenis, G.; Peerbooms, O.;
Visser, P. J.; Verhey, F.; van Os, J.; Steinbusch, H. W.; van den Hove,
D. L. Epigenetic regulation in the pathophysiology of Alzheimer's
disease. Prog. Neurobiol. 2010, 90, 498-510.
AUTHOR INFORMATION
Corresponding Author
9.
Pal, S.; Tyler, J. K. Epigenetics and aging. Science Advances
* Maria Laura Bolognesi: marialaura.bolognesi@unibo.it
* Luiz Antonio Soares Romeiro: luizromeiro@unb.br
2016, 2, e1600584.
10.
Yang, S.-s.; Zhang, R.; Wang, G.; Zhang, Y.-f. The
development prospection of HDAC inhibitors as a potential therapeutic
direction in Alzheimer’s disease. Translational Neurodegeneration
2017, 6, 19.
Author Contributions
The manuscript was written through contributions of all authors.
All authors have given approval to the final version of the
manuscript.
11.
Report.
Closing In On A Cure: 2017 Alzheimer’s Clinical Trials
https://www.alzdiscovery.org/assets/content/static/ADDF-
2017-Alzheimers-Clinical-Trials-Report.pdf (accessed March 2019)
12. Kilgore, M.; Miller, C. A.; Fass, D. M.; Hennig, K. M.;
Haggarty, S. J.; Sweatt, J. D.; Rumbaugh, G. Inhibitors of class 1
histone deacetylases reverse contextual memory deficits in a mouse
model of Alzheimer's disease. Neuropsychopharmacology 2010, 35,
870-880.
Funding Sources
LASR was supported by the University of Brasilia (CNPq
#401864/2013-8) MLB was supported by a grant of Visiting
Professor (PVE–CNPq #401864/2013-8) from the programme
“Ciência sem Fronteiras”, Brazil. This work was supported by the
University of Bologna (Grant RFO 2016). M. J. thanks the
Deutsche Forschungsgemeinschaft (DFG, Ju295/13-1) for funding.
O.S. thanks to project MH CZ – DRO (UHHK, 00179906) and T.
K. to student project no. SV/FVZ201708
13.
Lemes, L. F. N.; de Andrade Ramos, G.; de Oliveira, A. S.;
da Silva, F. M. R.; de Castro Couto, G.; da Silva Boni, M.; Guimaraes,
M. J. R.; Souza, I. N. O.; Bartolini, M.; Andrisano, V.; do Nascimento
Nogueira, P. C.; Silveira, E. R.; Brand, G. D.; Soukup, O.; Korabecny,
J.; Romeiro, N. C.; Castro, N. G.; Bolognesi, M. L.; Romeiro, L. A. S.
Cardanol-derived AChE inhibitors: Towards the development of dual
binding derivatives for Alzheimer's disease. Eur. J. Med. Chem. 2016,
108, 687-700.
Notes
The authors declare no competing financial interest.
14.
Cashew Nut Shell Waste. Top Curr. Chem. (Cham) 2018, 376, 8.
15. Balasubramanyam, K.; Swaminathan, V.; Ranganathan, A.;
Mubofu, E. B.; Mgaya, J. E. Chemical Valorization of
Kundu, T. K. Small molecule modulators of histone acetyltransferase
p300. J. Biol. Chem. 2003, 278, 19134-19140.
ACKNOWLEDGMENT
The authors acknowledge Epigenetic Chemical Biology
(Epichembio) COST Action CM1406. LASR is a senior fellow of
the National Council of Research (CNPq, DT2 #312709/2017-0,
Brazil).
16.
Sbardella, G.; Castellano, S.; Vicidomini, C.; Rotili, D.;
Nebbioso, A.; Miceli, M.; Altucci, L.; Mai, A. Identification of long
chain alkylidenemalonates as novel small molecule modulators of
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
Page 6 of 7
histone acetyltransferases. Bioorg. Med. Chem. Lett. 2008, 18, 2788-
2792.
17.
1
2
3
4
Ghizzoni, M.; Boltjes, A.; Graaf, C.; Haisma, H. J.; Dekker,
F. J. Improved inhibition of the histone acetyltransferase PCAF by an
anacardic acid derivative. Bioorg. Med. Chem. 2010, 18, 5826-5834.
18.
Ghizzoni, M.; Wu, J.; Gao, T.; Haisma, H. J.; Dekker, F. J.;
George Zheng, Y. 6-alkylsalicylates are selective Tip60 inhibitors and
target the acetyl-CoA binding site. Eur. J. Med. Chem. 2012, 47, 337-
344.
5
6
7
8
19.
Lomonaco, D.; Mele, G.; Mazzetto, S. E. Cashew Nutshell
Liquid (CNSL): From an Agro-industrial Waste to a Sustainable
Alternative to Petrochemical Resources. In Cashew Nut Shell Liquid,
Springer International Publishing AG: Cham, 2017; pp. 19-38.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
20.
Butler, K. V.; Kalin, J.; Brochier, C.; Vistoli, G.; Langley,
B.; Kozikowski, A. P. Rational Design and Simple Chemistry Yield a
Superior, Neuroprotective HDAC6 Inhibitor, Tubastatin A. J. Am.
Chem. Soc. 2010, 132, 10842-10846.
21.
Bourguet, E.; Ozdarska, K.; Moroy, G.; Jeanblanc, J.;
Naassila, M. Class I HDAC Inhibitors: Potential New Epigenetic
Therapeutics for Alcohol Use Disorder (AUD). J. Med. Chem. 2018,
61, 1745-1766.
22.
Simões-Pires, C.; Zwick, V.; Nurisso, A.; Schenker, E.;
Carrupt, P.-A.; Cuendet, M. HDAC6 as a target for neurodegenerative
diseases: what makes it different from the other HDACs? Molecular
Neurodegeneration 2013, 8, 7.
23.
Heltweg, B.; Trapp, J.; Jung, M. In vitro assays for the
determination of histone deacetylase activity. Methods (San Diego,
Calif.) 2005, 36, 332-337.
24.
L.; Wagner, F.; Holson, E.; Haggarty, S. J.; Weiss, P.; King, P.; Carter,
P.; Volkow, N. D.; Fowler, J. S.; Hooker, J. M.; Kim, S. W. Image-
guided synthesis reveals potent blood-brain barrier permeable histone
deacetylase inhibitors. ACS Chem. Neurosci. 2014, 5, 588-596.
Seo, Y. J.; Kang, Y.; Muench, L.; Reid, A.; Caesar, S.; Jean,
25.
Caraci, F.; Leggio, G. M.; Drago, F.; Salomone, S.
Epigenetic drugs for Alzheimer's disease: hopes and challenges. Br. J.
Clin. Pharmacol. 2013, 75, 1154-1155.
26.
Massenzio, F.; Petralla, S.; Rossi, M.; Roberti, M.; Martinez Gonzalez,
L.; Martinez, A.; Monti, B.; Bolognesi, M. L. A Focused Library of
Psychotropic Analogues with Neuroprotective and Neuroregenerative
Potential. ACS Chem. Neurosci. 2018, 10.1, 279-294.
Uliassi, E.; Pena-Altamira, L. E.; Morales, A. V.;
27.
Wang, G.; Shi, Y.; Jiang, X.; Leak, R. K.; Hu, X.; Wu, Y.;
Pu, H.; Li, W. W.; Tang, B.; Wang, Y.; Gao, Y.; Zheng, P.; Bennett,
M. V.; Chen, J. HDAC inhibition prevents white matter injury by
modulating microglia/macrophage polarization through the
GSK3beta/PTEN/Akt axis. Proc. Natl. Acad. Sci. U S A 2015, 112,
2853-2858.
28.
Hwang, J. Y.; Aromolaran, K. A.; Zukin, R. S. The emerging
field of epigenetics in neurodegeneration and neuroprotection. Nat.
Rev. Neurosci. 2017, 18, 347-361.
29.
Nostrand, W. E.; Vitek, M. P. Expression profiles for macrophage
alternative activation genes in AD and in mouse models of AD. J.
Neuroinflammation 2006, 3, 27.
Colton, C. A.; Mott, R. T.; Sharpe, H.; Xu, Q.; Van
30.
Pena-Altamira, E.; Petralla, S.; Massenzio, F.; Virgili, M.;
Bolognesi, M. L.; Monti, B. Nutritional and Pharmacological Strategies
to Regulate Microglial Polarization in Cognitive Aging and
Alzheimer's Disease. Front. Aging Neurosci. 2017, 9, 175.
31.
Thomas, E. A.; D'Mello, S. R. Complex neuroprotective and
neurotoxic effects of histone deacetylases. J. Neurochem. 2018, 145,
96-110.
32.
Lemgruber, L.; Bergamini, C.; Watson, D. G.; de, A. M. F. T.; Roth
Cardoso, G. S. H.; Soares Romeiro, L. A.; de Koning, H. P.; Bolognesi,
M. L. Discovery of Sustainable Drugs for Neglected Tropical Diseases:
Cashew Nut Shell Liquid (CNSL)-Based Hybrids Target
Mitochondrial Function and ATP Production in Trypanosoma brucei.
Chem Med Chem 2019, 14, 621.
Cerone, M.; Uliassi, E.; Prati, F.; Ebiloma, G. U.;
ACS Paragon Plus Environment

Page 7 of 7
ACS Medicinal Chemistry Letters
1
2
For Table of Contents Use Only
3
4
5
6
7
8
9
Novel sustainable-by-design HDAC inhibitors for the treatment of
Alzheimer’s disease
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Luiz Antonio Soares Romeiro,* Jéssica Larissa da Costa Nunes, Camila de Oliveira Miranda,
Gabriella Simões Heyn Roth Cardoso, Andressa Souza de Oliveira, Annachiara Gandini, Tereza
Kobrlova, Ondrej Soukup, Michele Rossi, Johanna Senger, Manfred Jung, Silvia Gervasoni, Giulio
Vistoli, Sabrina Petralla, Francesca Massenzio, Barbara Monti, Maria Laura Bolognesi*
ACS Paragon Plus Environment