0000000000210896
AUTHOR
Maria Zappalà
showing 24 related works from this author
Development of novel 1,4-benzodiazepine-based Michael acceptors as antitrypanosomal agents
2016
Novel 1,4-benzodiazepines, endowed with a Michael acceptor moiety, were designed taking advantage of a computational prediction of their pharmacokinetic parameters. Among all the synthesized derivatives, we identified a new lead compound (i.e., 4a), bearing a vinyl ketone warhead and endowed with a promising antitrypanosomal activity against Trypanosoma brucei brucei (IC50 = 5.29 µM), coupled with a lack of cytotoxicity towards mammalian cells (TC50>100 µM).
Identification of a new series of amides as non-covalent proteasome inhibitors
2014
Proteasome inhibition has emerged as an important therapeutic strategy for the treatment of multiple myeloma (MM) and some forms of lymphoma, with potential application in other types of cancers. 20S proteasome consists of three different catalytic activities known as chymotrypsin-like (ChT-L), trypsin-like (T-L), and, post-glutamyl peptide hydrolyzing (PGPH) or caspase-like (C-L), which are located respectively on the β5, β2, and β1 subunits of each heptameric β rings. Currently a wide number of covalent proteasome inhibitors are reported in literature; however, the less widely investigated non-covalent inhibitors might be a promising alternative to employ in therapy, because of the lack o…
Drug combination studies of curcumin and genistein against rhodesain of Trypanosoma brucei rhodesiense
2018
Curcumin and genistein are two natural products obtained from Curcuma longa L. and soybeans, endowed with many biological properties. Within the last years they were shown to possess also a promising antitrypanosomal activity. In the present paper, we investigated the activity of both curcumin and genistein against rhodesain, the main cysteine protease of Trypanosoma brucei rhodesiense; drug combination studies, according to Chou and Talalay method, allowed us to demonstrate a potent synergistic effect for the combination curcumin-genistein. As a matter of fact, with our experiments we observed that the combination index of curcumin-genistein is < 1 for the reduction from 10 to 90% of rhode…
Synthesis and anti-HIV activity of 2,3-diaryl-1,3-thiazolidin-4-ones
2002
Several 1,3-thiazolidin-4-ones bearing a 2,6-dihalophenyl group at C-2 and a variously substituted phenyl ring at N-3 have been synthesized and tested as anti-HIV agents. The results of the in vitro tests showed that some of them proved to be effective inhibitors of HIV-1 replication.
Synthesis and biological evaluation of novel peptidomimetics as rhodesain inhibitors
2016
Novel rhodesain inhibitors were developed by combining an enantiomerically pure 3-bromoisoxazoline warhead with a 1,4-benzodiazepine scaffold as specific recognition moiety. All compounds were proven to inhibit rhodesain with Ki values in the low-micromolar range. Their activity towards rhodesain was found to be coupled to an in vitro antitrypanosomal activity, with IC50 values ranging from the mid-micromolar to a low-micromolar value for the most active rhodesain inhibitor (R,S,S)-3. All compounds showed a good selectivity against the target enzyme since all of them were proven to be poor inhibitors of human cathepsin L. Novel rhodesain inhibitors were developed by combining an enantiomeri…
Development of novel dipeptide-like rhodesain inhibitors containing the 3-bromoisoxazoline warhead in a constrained conformation.
2015
Novel dipeptide-like rhodesain inhibitors containing the 3-bromoisoxazoline warhead in a constrained conformation were developed; some of them possess K(i) values in the micromolar range. We studied the structure-activity relationship of these derivatives and we performed docking studies, which allowed us to find out the key interactions established by the inhibitors with the target enzyme. Biological results indicate that the nature of the P2 and P3 substituents and their binding to the S2/S3 pockets is strictly interdependent.
Synthesis and biological evaluation of papain-family cathepsin L-like cysteine protease inhibitors containing a 1,4-benzodiazepine scaffold as antipr…
2014
Novel papain-family cathepsin L-like cysteine protease inhibitors endowed with antitrypanosomal and antimalarial activity were developed, through an optimization study of previously developed inhibitors. In the present work, we studied the structure-activity relationships of these derivatives, with the aim to develop new analogues with a simplified and more synthetically accessible structure and with improved antiparasitic activity. The structure of the model compounds was significantly simplified by modifying or even eliminating the side chain appended at the C3 atom of the benzodiazepine scaffold. In addition, a simple methylene spacer of appropriate length was inserted between the benzod…
Synthesis and anti-HIV activity of 2,3-diaryl-1,3-thiazolidin-4-(thi)one derivatives.
2002
Several 2,3-diaryl-1,3-thiazolidine-4-thione derivatives and 2,3-diaryl-1,3-thiazolidin-4-ones bearing a methyl group at C-5 position have been synthesized and tested as anti-HIV agents. The results of the in vitro tests showed that some of them proved to be effective inhibitors of HIV-1 replication.
Peptidyl Vinyl Ketone Irreversible Inhibitors of Rhodesain: Modifications of the P2 Fragment.
2020
In this paper, we report the design, synthesis and biological investigation of a series of peptidyl vinyl ketones obtained by modifying the P2 fragment of previously reported highly potent inhibitors of rhodesain, the main cysteine protease of Trypanosoma brucei rhodesiense. Investigation of the structure-activity relationship led us to identify new rhodesain inhibitors endowed with an improved selectivity profile (a selectivity index of up to 22 000 towards the target enzyme), and/or an improved antitrypanosomal activity in the sub-micromolar range.
Identification of noncovalent proteasome inhibitors with high selectivity for chymotrypsin-like activity by a multistep structure-based virtual scree…
2016
Noncovalent proteasome inhibitors introduce an alternative mechanism of inhibition to that of covalent inhibitors, e.g. carfilzomib, used in cancer therapy. A multistep hierarchical structure-based virtual screening (SBVS) of the 65,375 NCI lead-like compound library led to the identification of two compounds (9 and 28) which noncovalently inhibited the chymotrypsin-like (ChT-L) activity (Ki = 2.18 and 2.12 μM, respectively) with little or no effects on the other two major proteasome proteolytic activities, trypsin-like (T-L) and post-glutamyl peptide hydrolase (PGPH) activities. A subsequent hierarchical similarity search over the full NCI database with the most active tripeptide-based inh…
Drug Synergism: Studies of Combination of RK-52 and Curcumin against Rhodesain of Trypanosoma brucei rhodesiense
2020
Rhodesain is an enzyme essential for the life of Trypanosoma brucei rhodesiense, a parasite causing a rapid-onset form of Human African Trypanosomiasis. RK-52 is a synthetic inhibitor of rhodesain,...
Exploring the SARS-CoV-2 Proteome in the Search of Potential Inhibitors via Structure-based Pharmacophore Modeling/Docking Approach
2020
To date, SARS-CoV-2 infectious disease, named COVID-19 by the World Health Organization (WHO) in February 2020, has caused millions of infections and hundreds of thousands of deaths. Despite the scientific community efforts, there are currently no approved therapies for treating this coronavirus infection. The process of new drug development is expensive and time-consuming, so that drug repurposing may be the ideal solution to fight the pandemic. In this paper, we selected the proteins encoded by SARS-CoV-2 and using homology modeling we identified the high-quality model of proteins. A structure-based pharmacophore modeling study was performed to identify the pharmacophore features for each…
Evaluation of curcumin irreversibility
2019
Dear Editor,We would like to reply to the letter to the Editor of Steverding (2018) on our research article “Drug combination studies of curcumin and genistein against rhodesain of Trypanosoma bruc...
Optimization of peptidomimetic boronates bearing a P3 bicyclic scaffold as proteasome inhibitors
2014
Abstract A new series of pseudopeptide boronate proteasome inhibitors (2–3) was developed, through optimization of our previously described analogs of bortezomib, bearing a bicyclic 1,6-naphthyridin-5(6H)-one scaffold as P3 fragment (1). The biological evaluation on human 20S proteasome displayed a promising inhibition profile, especially for compounds bearing a P2 ethylene fragment, which exhibited Ki values in the nanomolar range for the ChT-L activity (e.g. 2a, Ki = 0.057 μM) and considerable selectivity for proteasome over bovine pancreatic α-chymotrypsin. Docking experiments into the yeast 20S proteasome revealed that the ligands are accommodated predominantly into the ChT-L site and t…
Immunoproteasome and Non-Covalent Inhibition: Exploration by Advanced Molecular Dynamics and Docking Methods
2021
The selective inhibition of immunoproteasome is a valuable strategy to treat autoimmune, inflammatory diseases, and hematologic malignancies. Recently, a new series of amide derivatives as non-covalent inhibitors of the β1i subunit with Ki values in the low/submicromolar ranges have been identified. Here, we investigated the binding mechanism of the most potent and selective inhibitor, N-benzyl-2-(2-oxopyridin-1(2H)-yl)propanamide (1), to elucidate the steps from the ligand entrance into the binding pocket to the ligand-induced conformational changes. We carried out a total of 400 ns of MD-binding analyses, followed by 200 ns of plain MD. The trajectories clustering allowed identifying thre…
Development of Novel Benzodiazepine-Based Peptidomimetics as Inhibitors of Rhodesain from Trypanosoma brucei rhodesiense.
2020
Starting from the reversible rhodesain inhibitors 1 a-c, which have Ki values towards the target protease in the low-micromolar range, we have designed a series of peptidomimetics, 2 a-g, that contain a benzodiazepine scaffold as a β-turn mimetic; they are characterized by a specific peptide sequence for the inhibition of rhodesain. Considering that irreversible inhibition is strongly desirable in the case of a parasitic target, a vinyl ester moiety acting as Michael-acceptor was introduced as the warhead; this portion was functionalized in order to evaluate the size of corresponding enzyme pocket that could accommodate this substituent. With this investigation, we identified an irreversibl…
Optimization Strategy of Novel Peptide-Based Michael Acceptors for the Treatment of Human African Trypanosomiasis
2019
This paper describes an optimization strategy of the highly active vinyl ketone 3 which was recognized as a strong inhibitor of rhodesain of Trypanosoma brucei rhodesiense, endowed with a ksecond v...
2-(2,6-Dihalophenyl)-3-(pyrimidin-2-yl)-1,3-thiazolidin-4-ones as non-nucleoside HIV-1 reverse transcriptase inhibitors.
2004
Several 1,3-thiazolidin-4-ones bearing a 2,6-dihalophenyl group at C-2 and a substituted pyrimidin-2-yl ring at the N-3 were synthesised and evaluated as anti-HIV agents. The results of the in vitro tests showed that some of them were highly effective inhibitors of human immunodeficiency virus type-1 (HIV-1) replication at 10–40 nM concentrations with minimal cytotoxicity. Structure–activity relationship studies revealed that the nature of the substituents at the 2 and 3 positions of the thiazolidinone nucleus had a significant impact on the in vitro anti-HIV activity of this class of potent antiretroviral agents. The compounds had significantly reduced activity against the characteristic N…
Synthesis and Molecular Modeling Studies of Derivatives of a Highly Potent Peptidomimetic Vinyl Ester as Falcipain-2 Inhibitors
2012
Herein we report the synthesis of a set of constrained peptidomimetics endowed with an electrophilic vinyl ester warhead and structurally related to a previously identified lead compound, a potent and irreversible inhibitor of falcipain-2 (FP-2). FP-2 is the main hemoglobinase of the malaria parasite P. falciparum. The new compounds were evaluated for their inhibition against FP-2, and the results were rationalized on the basis of docking experiments. These studies underscore the pivotal role of both the ester function at the P1' site and the trifluoromethyl group of the P3 side chain in determining the correct orientation of the Michael acceptor warhead in the catalytic site, and as a cons…
Development of Novel Peptide-Based Michael Acceptors Targeting Rhodesain and Falcipain-2 for the Treatment of Neglected Tropical Diseases (NTDs)
2017
This paper describes the development of a class of peptide-based inhibitors as novel antitrypanosomal and antimalarial agents. The inhibitors are based on a characteristic peptide sequence for the inhibition of the cysteine proteases rhodesain of Trypanosoma brucei rhodesiense and falcipain-2 of Plasmodium falciparum. We exploited the reactivity of novel unsaturated electrophilic functions such as vinyl-sulfones, -ketones, -esters, and -nitriles. The Michael acceptors inhibited both rhodesain and falcipain-2, at nanomolar and micromolar levels, respectively. In particular, the vinyl ketone 3b has emerged as a potent rhodesain inhibitor (k2nd = 67 × 106 M-1 min-1), endowed with a picomolar b…
Lead Discovery of SARS-CoV-2 Main Protease Inhibitors through Covalent Docking-Based Virtual Screening
2021
During almost all 2020, coronavirus disease 2019 (COVID-19) pandemic has constituted the major risk for the worldwide health and economy, propelling unprecedented efforts to discover drugs for its prevention and cure. At the end of the year, these efforts have culminated with the approval of vaccines by the American Food and Drug Administration (FDA) and the European Medicines Agency (EMA) giving new hope for the future. On the other hand, clinical data underscore the urgent need for effective drugs to treat COVID-19 patients. In this work, we embarked on a virtual screening campaign against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Mpro chymotrypsin-like cysteine pro…
Development of peptidomimetic boronates as proteasome inhibitors.
2013
Abstract Proteasome inhibition has emerged over the past decade as an effective therapeutic approach for the treatment of hematologic malignancies. It is a multicatalytic complex, whose proteolytic activity relies in three types of subunits: chymotrypsin-like (β5), trypsin-like (β2) and caspase-like (β1). Most important for the development of effective antitumor agents is the inhibition of the β5 subunits. In this context, the dipeptide boronate bortezomib (Velcade ® ) represents the first proteasome inhibitor approved by the FDA and the lead compound in drug discovery. This paper describes the synthesis and biological evaluation of a series of conformationally constrained pseudopeptide bor…
Synthesis of new 2,3-diaryl-1,3-thiazolidin-4-ones as anti-HIV agents
2004
Several 2,3-diaryl-1,3-thiazolidin-4-ones were synthesized and evaluated as anti-HIV agents. The results of the in vitro tests showed that some of them were highly effective inhibitors of HIV-1 replication at 30-50 nM concentrations with minimal cytotoxicity, thereby acting as non-nucleoside HIV-1 reverse transcriptase inhibitors (NNRTIs).
Sulfonamide moiety as "molecular chimera" in the design of new drugs.
2021
Background: The -SO2NH- group is of great significance in modern pharmaceutical use since, in sulfa-drugs, it is possible to introduce easily chemical modifications, and even small changes may lead to an improved version of an already existing drug. Objective: This paper aims to describe updated information in the sulfonamide field with a particular focus on new mechanisms of action, especially if discovered by employing computational approaches. Methods: Research articles that focused on the use of the sulfonamide moiety for the design, synthesis, and in vitro/in vivo tests of various diseases were collected from various search engines like PubMed, Science Direct, Google Scholar, and Scop…