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Since late December 2019, severe acute respiratory syndrome coronavirus 2 has spread across the world, which resulted in the World Health Organization declaring a global pandemic. Coronavirus disease 2019 (COVID-19) presents a highly variable spectrum with regard to the severity of illness. Most infected individuals exhibit a mild to moderate illness (81%); however, 14% have a serious disease and 5% develop severe acute respiratory distress syndrome (ARDS), requiring intensive care support. The mortality rate of COVID-19 continues to rise across the world. Data regarding predictors of mortality in patients with COVID 19 are still scarce but are being actively investigated. The present multicenter retrospective observational study provides a complete description of the demographic and clinical characteristics, comorbidities and laboratory abnormalities in a population of 421 hospitalized patients recruited across eight infectious disease units in Southern Italy (Sicily) with the aim of identifying the baseline characteristics predisposing COVID-19 patients to critical illness or death. In this study, older age, pre-existing comorbidities and certain changes in laboratory markers (such as neutrophilia, lymphocytopenia and increased C-reactive protein levels) at the time of admission were associated with a higher risk of mortality. Male sex, on the other hand, was not significantly associated with increased risk of mortality. Symptoms such as fatigue, older age, a number of co-pathologies and use of continuous positive airway pressure were the most significant contributors in the estimation of clinical prognosis. Further research is required to better characterize the epidemiological features of COVID-19, to understand the related predictors of death and to develop new effective therapeutic strategies.

The development of immunoproteasome-selective inhibitors is a promising strategy for treating hematologic malignancies, autoimmune and inflammatory diseases. In this context, we report the design, synthesis, and biological evaluation of a new series of amide derivatives as immunoproteasome inhibitors. Notably, the designed compounds act as noncovalent inhibitors, which might be a promising therapeutic option because of the lack of drawbacks and side effects associated with irreversible inhibition. Among the synthesized compounds, we identified a panel of active inhibitors with Ki values in the low micromolar or sub-micromolar ranges toward the b5i and/or b1i subunits of immunoproteasomes. One of the active compounds was shown to be the most potent and selective inhibi-tor with a Ki value of 21 nm against the single b1i subunit. Docking studies allowed us to determine the mode of binding of the molecules in the catalytic site of immunoproteasome subunits.

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...

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

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 binding affinity (Ki = 38 pM), coupled with a single-digit micromolar activity against Trypanosoma brucei brucei (EC50 = 2.97 μM), thus being considered as a novel lead compound for the discovery of novel effective antitrypanosomal agents.

Objectives: The aim of our study was to evaluate the clinicopathological features and prognostic factors of uterine carcinosarcoma. Patients and Methods: In this retrospective study, the clinical characteristics of 44 patients with uterine MMMT were evaluated. Survival curves were estimated by the Kaplan-Meier method and compared by the log-rank test. Results: Forty-four patients with uterine carcinosarcoma were referred to our unit between 1995 and 2015. Their median age was 66.5 years. All women underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Twenty-five percent had omental resection. Pelvic lymphadenectomy was performed in 18.2% of the cases. Twenty-six of the patients presented with stage I/II disease, 17 with advanced stages. In 20.5% of the cases there were metastases at diagnosis. Forty women received adjuvant chemotherapy, with complete remission in 67.9% of the cases. Recurrences were observed in 27.3% of the women. Disease-free and overall survival was 27 and 103 months, respectively. The FIGO stage, histological type, tumour size, chemotherapy regimen, pelvic lymphadenectomy, and myometrial invasion did not affect survival. Conclusions: Uterine MMMT is an aggressive tumour, often diagnosed at an advanced stage and with a high rate of metastases or recurrences. Because of its rarity, its management is controversial and fixed prognostic factors cannot be defined.

Human African Trypanosomiasis (HAT) is an endemic parasitic disease of sub-Saharan Africa, caused by two subspecies of protozoa belonging to Trypanosoma genus: T. brucei gambiense and T. brucei rhodesiense. In this context the inhibition of the papain-family cysteine proteases rhodesain and TbCatB has to be considered a promising strategy for HAT treatment. Rhodesain, the major cathepsin L-like cysteine protease of T. brucei rhodesiense, is a lysosomal protease essential for parasite survival. It is involved in parasite invasivity, allowing it to cross the blood-brain barrier (BBB) of the human host, causing the second lethal stage of the disease. Moreover, it plays an important role in immunoevasion, being involved in the turnover of variant surface glycoproteins of the T. brucei coat and in the degradation of immunoglobulins, avoiding a specific immune response by the host cells. On the other hand TbCatB, a cathepsin B-like cysteine protease, present in minor abundance in T. brucei, showed a key role in the degradation of host transferrin, which is necessary for iron acquisition by the parasite. In this review article we now discuss the most active peptide, peptidomimetic and non-peptide rhodesain and TbCatB inhibitors as valuable strategy to treat HAT, due also to the complementary role of the two T. brucei proteases.

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).

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 enantiomerically pure 3-bromoisoxazoline warhead with a 1,4-benzodiazepine scaffold as specific recognition moiety. All compounds were proven to inhibit rhodesain with K-i 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.

Conformational analysis of a potent class of cysteine protease inhibitors is thoroughly studied by NMR, in both, polar and apolar solvents to get a better insight over the known biological activity and migration through biological media. These molecules are composed by a benzodiazepine (BDZ) scaffold connected to a bromo-isoxazoline (IOX) ring through an alkyl spacer (AS) with up to four-carbon atoms. Data, supported by theoretical calculations at DFT level, reveal that both BDZ and IOX keep a pretty rigid and asymmetric conformation, so that four diastereo-atropisomers (two mirror-image couples) are generated. The relative stiffness of these substrates, maintained also in different solvents, is confirmed by: (a) remarkable separation of diastereotopic protons; (b) specific “through the space contacts” (NOESY); and (c) very good fitting of the coupling constants evaluations. The prototypic compound with the longer AS shows two main conformations and a certain dynamic freedom around the AS torsional angles close to IOX; according to our data, the AS length is not fundamental for the functional BDZ and IOX fitting into the macromolecular complex; however, it does play a crucial role to cross the parasite cell membranes.

This paper describes the design, synthesis, and biological evaluation of 2-thioxoimidazolidin-4-one derivatives as inhibitors of proteasome and immunoproteasome, potential targets for the treatment of hematological malignancies. In particular, we focused our efforts on the design of noncovalent inhibitors, which might be a promising therapeutic option potentially devoid of drawbacks and side-effects related to irreversible inhibition. Among all the synthesized compounds, we identified a panel of active inhibitors with Ki values towards one or two chymotrypsin-like activities of proteasome (β5c) and immunoproteasome (β5i and β1i subunits) in the low micromolar range. Docking studies suggested a unique binding mode of the molecules in the catalytic site of immunoproteasome proteolytic subunits.

The ubiquitin-proteasome system (UPS) is the major non-lysosomal proteolytic system for the degradation of abnormal or damaged proteins no longer required. The proteasome is involved in degradation of numerous proteins which regulate the cell cycle, indicating a role in controlling cell proliferation and maintaining cell survival. Defects in the UPS can lead to anarchic cell proliferation and to tumor development. For these reasons UPS inhibition has become a significant new strategy for drug development in cancer treatment. In addition to the constitutive proteasome, which is expressed in all cells and tissues, higher organisms such as vertebrates possess two immune-type proteasomes, the thymoproteasome and the immunoproteasome. The thymoproteasome is specifically expressed by thymic cortical epithelial cells and has a role in positive selection of CD8+ T cells, whereas the immunoproteasome is predominantly expressed in monocytes and lymphocytes and is responsible for the generation of antigenic peptides for cell-mediated immunity. Recent studies demonstrated that the immunoproteasome has a preservative role during oxidative stress and is up-regulated in a number of pathological disorders including cancer, inflammatory and autoimmune diseases. As a consequence, immunoproteasome-selective inhibitors are currently the focus of anticancer drug design. At present, the commercially available proteasome inhibitors bortezomib and carfilzomib which have been validated in multiple myeloma and other model systems, appear to target both the constitutive and immunoproteasomes, indiscriminately. This lack of specificity may, in part, explain some of the side effects of these agents, such as peripheral neuropathy and gastrointestinal effects, which may be due to targeting of the constitutive proteasome in these tissues. In contrast, by selectively inhibiting the immunoproteasome, it may be possible to maintain the antimyeloma and antilymphoma efficacy while reducing these toxicities, thereby increasing the therapeutic index. This review article will be focused on the discussion of the most promising immunoproteasome specific inhibitors which have been developed in recent years. Particular attention will be devoted to the description of their mechanism of action, their structure-activity relationship, and their potential application in therapy.

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 that they covalently bind to the active site threonine residue via boron atom. Within the cellular assays performed against a 60 cancer cell line panel, compounds 3e and 3f demonstrated also good antiproliferative activity and compound 3f emerged as promising lead compound for the development of anticancer agents targeting melanoma and non-small cell lung cancer.

The identification of the key role of the eukaryotic 26S proteasome in regulated intracellular proteolysis and its importance as a target in many pathological conditions wherein the proteasomal activity is defective (e.g., malignancies, autoimmune diseases, neurodegenerative diseases, etc.) prompted several research groups to the development of specific inhibitors of this multicatalytic complex with the aim of obtaining valid drug candidates. In regard to the anticancer therapy, the peptide boronate bortezomib (Velcade®) represents the first molecule approved by FDA for the treatment of multiple myeloma in 2003 and mantle cell lymphoma in 2006. Since then, a plethora of molecules targeting the proteasome have been identified as potential anticancer agents and a few of them reached clinical trials or are already in the market (i.e., carfilzomib; Kyprolis®). In most cases, the design of new proteasome inhibitors (PIs) takes into account a proven peptide or pseudopeptide motif as a base structure and places other chemical entities throughout the peptide skeleton in such a way to create an efficacious network of interactions within the catalytic sites. The purpose of this review is to provide an in-depth look at the current state of the research in the field of peptide-based PIs, specifically those ones that might find an application as anticancer agents.

In this work, we designed and synthesized novel N-3-bromoisoxazolin-5-yl substituted 2,3-benzodiazepines as noncompetitive AMPAR antagonists, with the aim that this heterocycle could establish favourable interactions with a putative binding pocket of the receptor, like the thiadiazole nucleus of GYKI 47409 does. Within this investigation, we identified some active molecules and, among these 2,3-benzodiazepines, 4c showed a much improved inhibitory potency as compared with unsubstituted 2,3-benzodiazepines.

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 consequence, the potency of the inhibitors as well as their reversible or irreversible mode of inhibition.

This article describes the synthesis and the biological evaluation of two sets of benzothiazole derivatives bearing at C-2 an arylamide (1a–e, 2a–e) or an arylurea (3a–d, 4a–d) moiety. Five compounds (3d and 4a–d) were selected and screened by the National Cancer Institute for the in vitro primary anticancer assay against a panel of 60 human tumor cell lines. Compounds 4a and 4c showed interesting anticancer activities, more marked for compound 4c. All compounds were also submitted to a preliminary in vitro assay as potential inhibitors of the ubiquitin-activating enzyme (E1), but they lacked significant activity.

Herein we report the synthesis of a series of novel constrained peptidomimetics 2-10 endowed with a dipeptide backbone (D-Ser-Gly) and a vinyl ester warhead, structurally related to a previously identified lead compound 1, an irreversible inhibitor of falcipain-2, the main haemoglobinase of lethal malaria parasite Plasmodium falciparum. The new compounds were evaluated for their inhibition against falcipain-2, as well as against cultured P. falciparum. The inhibitory activity of the synthesized compounds was also evaluated against another protozoal cysteine protease, namely rhodesain of Trypanosoma brucei rhodesiense.

This paper describes the synthesis of novel peptidomimetics bearing a protected aspartyl aldeyde warhead leading to the thioacylals 2a,b and the acylals 3a,b. Compounds 2a and 3a proved to possess an increased antiplasmodial activity with respect to the parent molecule 1. Furthermore thioacylal 2a can be considered as a promising trypanocidal agent.

A series of 1-aryl-6,7-disubstituted-2H-isoquinolin-3-ones (2-10) was synthesized and evaluated for their inhibition against Plasmodium falciparum cysteine protease falcipain-2, as well as against cultured P. falciparum strain FCBR parasites. All compounds displayed inhibitory activity against recombinant falcipain-2 and against in vitro cultured intraerythrocytic P. falciparum, with the exception of 9. The new compounds exhibited no selectivity against human cysteine proteases such as cathepsins B and L. The inhibitory activity of the synthesized compounds was also evaluated against another protozoal cysteine protease, namely rhodesain of Trypanosoma brucei rhodesiense.

Malaria, particularly that one caused by Plasmodium falciparum, remains a serious health problem in Africa, South America, and many parts of Asia where it afflicts about 500 million people and is responsible for the death of more than one million children each year. The main reasons for the persistence of malaria are the emergence of resistance to common antimalarial drugs, inadequate control of mosquito vectors, and the lack of effective vaccines. Therefore, the identification and characterization of new targets for antimalarial chemotherapy are of urgent priority. This review is focused on inhibitors of falcipain-2, a cysteine protease from P. falciparum, which represents one of the most promising targets for antimalarial drug design. Falcipain-2 is a key enzyme in the life cycle of P. falciparum since it degrades hemoglobin, at the early trophozoite stage, and cleaves ankyrin and protein 4.1, the cytoskeletal elements vital to the stability of red cell membrane, at the schizont stage. The main classes of falcipain-2 inhibitors are peptides or peptidomimetics bearing the most popular pharmacophores of cysteine protease inhibitors, such as vinyl sulfones, halomethyl ketones, and aldehydes. Furthermore, many other chemotypes have been identified as inhibitors of falcipain-2, such as isoquinolines, thiosemicarbazones, and chalcones. These inhibitors represent all classes, which, to the best of our knowledge, have been disclosed in journal articles to date. © 2009 Wiley Periodicals, Inc. Med Res Rev, 30, No. 1, 136–167, 2010

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 inhibitor 9 resulted in the discovery of the β5/β6-specific tripeptide derivative 38 that noncovalently binds the ChT-L site (Ki = 0.42 μM). The solution structure of 9 and 38 was solved by (1)H NMR spectroscopy and the binding mode of the inhibitors was elucidated by docking experiments using the yeast 20S proteasome. Compound 38 (IC50 = 26.7 μM) is slightly more potent than 9 (IC50 = 34.3 μM) at inhibiting survival of dexamethasone-resistant (MM.1R) human multiple myeloma cells. The identified ligand thus provides valuable insights for the future structure-based design of subtype-specific proteasome inhibitors.

The immunoproteasome is predominantly expressed in monocytes and lymphocytes and is responsible for the generation of antigenic peptides for cell-mediated immunity. Upon the exposure of inflammatory cytokines IFN-γ and TNF-α, constitutive subunits can be replaced by the synthesis of the immuno-core particles β1i, β2i and β5i. Recent studies demonstrated that the immunoproteasome function is not only limited to MHC class I presentation, but it is also implicated in a number of pathological disorders including hematological malignancies, inflammatory and autoimmune diseases. At present the commercially available proteasome inhibitors Bortezomib and Carfilzomib, which have been validated in multiple myeloma and other diseases, appear to target both the constitutive and immunoproteasomes indiscriminately. This lack of specificity may, in part, explain some of the side effects of these agents. In contrast, by selectively targeting the immunoproteasome, it may be possible to keep the antimyeloma and antilymphoma efficacy unchanged and, at the same time, to increase the therapeutic index. The aim of this review article is to discuss the most promising immunoproteasome core particle-selective inhibitors which have been developed in the recent years, with a particular attention to their structural features, mechanism of action and therapeutic application.

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.

A series of 3-(alkylcarbamoyl)-2-aryl-1,2-dihydro-6,7-(methylenedioxy)-3H-quinazolin-4-ones, compounds 3-6, were synthesized, and screened as anticonvulsant agents in DBA/2 mice against sound-induced seizure (Table). The new compounds were found to display anticonvulsant properties inferior to those of the known dehydro congeners 1 and 2. The binding affinities of 1-6 at the AMPA and NMDA receptors were also evaluated.

The resolution of 1-(4-aminophenyl)-7,8-methylenedioxy-1,2,3,5-tetrahydro-4H-benzodiazepin-4-one (±)-(R,S)-2 was accomplished by chiral HPLC. The absolute configuration of (+)-2, determined by X-ray crystallographic analysis, was R. The in vivo anticonvulsant activity of the enantiomers (+)-(R)-2 and (−)-(S)-2 is reported. It has been also demonstrated that compound (±)-(R,S)-2 in vivo undergoes oxidative metabolism to derivative 1. Chirality, 2006. © 2006 Wiley-Liss, Inc.

A series of 2-semicarbazonomethyl-4,5-methylenedioxyphenylacetic acids (12-19) were synthesized and tested as anticonvulsant agents in DBA/2 mice against sound-induced seizures and the results compared to those previously reported for the corresponding methyl esters (4-11). The new compounds possess anticonvulsant properties lower than those of 4-11, but, in some instances, comparable to that of GYKI 52466, a well-known noncompetitive AMPA receptor antagonist.

A series of 1-substituted 2-[(4-aryl)-methyl]-4,5-methylenedioxybenzene derivatives (13-25), structurally related to model compound 5 (2-[(4-aminophenyl)-(4-methylsemicarbazono)-methyl]-4,5-methylenedioxyphenylacetic acid methyl ester), were synthesized and tested as anticonvulsant agents in DBA/2 mice against sound-induced seizures. The new compounds possess anticonvulsant properties lower than those of prototype 5 but, in some instances, comparable to that of GYKI 52466, a well-known noncompetitive AMPA receptor antagonist.

2,3-Benzodiazepines are a well-known group of compounds for their potential antagonism against AMPA receptors. It has been previously reported that the inhibitory effect of 2,3-benzodiazepine derivatives with a 7,8-ethylenedioxy moiety can be enhanced by simply adding a chlorine atom at position 3 of the 4-aminophenyl ring. Here we report that adding a methyl group at position 3 on the 4-aminophenyl ring, termed as BDZ-11-7, can similarly enhance the inhibitory activity, as compared with the unsubstituted one or BDZ-11-2. Our kinetic studies have shown that BDZ-11-7 is a noncompetitive antagonist of GluA2Q homomeric receptors and prefers to inhibit the closed-channel state. However, adding another methyl group at position 5 on the 4-aminophenyl ring, termed as BDZ-11-6, fails to yield extra inhibition on GluA2Q receptors. Instead, BDZ-11-6 exhibits a diminished inhibition of GluA2Q. Site interaction test indicates the two compounds, BDZ-11-6 and BDZ-11-7, bind to the same site on GluA2Q, which is also the binding site for their prototype, BDZ-11-2. Based on the results from this and our earlier studies, we propose that the binding site that accommodates the 4-aminophenyl ring must contain two interactive points, with one preferring polar groups like chlorine and the other preferring nonpolar groups such as a methyl group. Either adding a chlorine or a methyl group may enhance the inhibitory activity of 2,3-benzodiazepine derivatives with a 7,8-ethylenedioxy moiety. Adding any two of the same group on positions 3 and 5 of the 4-aminophenyl ring, however, significantly reduces the interaction between these 2,3-benzodiazepines and their binding site, because one group is always repelled by one interactive point. We predict therefore that adding a chlorine atom at position 3 and a methyl group at position 5 of the 4-aminophenyl ring of 2,3-benzodiazepine derivatives with a 7,8-ethylenedioxy moiety may produce a new compound that is more potent.

In this paper we describe the synthesis of a series of novel 2-[(4-alkylsemicarbazono)-(4-aminophenyl)-methyl]-4,5-methylenedioxyphenylacetic acid alkyl esters (10-19) carrying an alkylsemicarbazono moiety at a benzylic site. The influence of this group on the biological activity was evaluated by testing the corresponding derivatives 20-22 in which the 4-alkylsemicarbazono moiety was removed (compound 20) or its alkylureido portion shifted at position 1 (compounds 21-22). Furthermore, the involvement of the 4-aminobenzyl moiety in the anticonvulsant activity was evaluated by testing derivative 23. The anticonvulsant activity of all compounds was assayed against audiogenic seizures induced in DBA/2 mice. Within this series of derivatives, 2-[(4-aminophenyl)-(4-methylsemicarbazono)-methyl]-4,5-methylenedioxyphenylacetic acid methyl ester (10) proved to be the most active compound. It displayed a potency 5-fold higher than that shown by 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine (1, GYKI 52466), a well-known noncompetitive 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptor antagonist. Compound 10 was also effective in suppressing seizures induced in Swiss mice by maximal electroshock (MES) or pentylenetetrazole (PTZ). Furthermore, it antagonized in vivo seizures induced by icv administration of AMPA or kainate (KA). Using the patch-clamp technique in primary cultures of granule neurons we tested compounds 10 and 21 for their ability to modulate currents evoked by KA and 2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propionic acid (ATPA). These two derivatives reduced KA and ATPA currents to a larger extent than that shown by reference compound 1. Compounds 10 and 21 were also able to reduce neuronal cell death induced by the application of KA (100 microM).

The synthesis of 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine (GYKI 52466, 1), the prototype of a series of noncompetitive AMPA receptor antagonists, and its 3,4-dihydroderivative (GYKI 52895, 2) is described. The title compounds have been prepared starting from safrole through a quite effective procedure.

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 benzodiazepine ring and the 3-bromoisoxazoline moiety. Several rhodesain and falcipain-2 inhibitors displaying single-digit micromolar or sub-micromolar antiparasitic activity against one or both parasites were identified, with activities that were one order of magnitude more potent than the model compounds.

There is increasing evidence of the potential therapeutic utility of glutamate receptor antagonists in the treatment of several neurodegenerative disorders, including stroke and epilepsy. In the last few years noncompetitive AMPA receptor antagonists have received considerable attention due to their therapeutic potentiality. The discovery of GYKI 52466, the prototype of noncompetitive AMPA receptor antagonists endowed with anticonvulsant and neuroprotective properties, induced growing interest on 2,3-benzodiazepine derivatives. This review covers the chemistry and pharmacology of this important class of AMPA receptor antagonists.

The synthesis and anticonvulsant activity of 1-aryl-7,8-methylenedioxy-1,2,3,5-tetrahydro-4H-2,3-benzodiazepin-4-(thi)ones (4a-d) and their 3-N-alkylcarbamoyl derivatives (4e-h) are reported. The new compounds possess marked anticonvulsant properties, comparable to those of the dehydro analogues 3 and higher than that of GYKI 52466 (1). Noteworthy, compound 4c shows a longer-lasting anticonvulsant activity. Electrophysiological experiments show that derivative 4c is less effective than 1 and 3c to reduce the KA-evoked currents in cerebellar granule neurons.

A series of 1 H ,3 H -thiazolo[4,3- b ]quinazolines ( 2a–i ) were synthesized and evaluated for their in vitro antitumour activity against ca. 60 human tumour cell lines. They exhibited moderate ( 2c , 2d , 2f and 2g ) to strong ( 2a , 2b , 2e , 2h and 2i ) cell-growth inhibition at a concentration of 10 −4 M, but weak activity at lower concentrations. Only 1-(2,6-dichlorophenyl)-1 H ,3 H -thiazolo[4,3- b ]quinazoline ( 2h ) possesses a significant growth inhibitory activity on 22 cell lines at a concentration of 10 −5 M.

We have previously shown that 1-aryl-3,5-dihydro-7, 8-methylenedioxy-4H-2,3-benzodiazepin-4-ones (3) possess marked anticonvulsant properties and antagonize seizures induced by 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) in analogy to the structurally related 1-(4-aminophenyl)-4-methyl-7, 8-methylenedioxy-5H-2,3-benzodiazepine (1, GYKI 52466), a well-known noncompetitive AMPA/kainate receptor antagonist. We now report the synthesis of 3-(N-alkylcarbamoyl)-1-aryl-3,5-dihydro-7, 8-methylenedioxy-4H-2,3-benzodiazepin-4-ones (4a-h) and 1-aryl-3, 5-dihydro-7,8-methylenedioxy-4H-2,3-benzodiazepine-4-thiones (5a-c). The activity of all compounds, intraperitoneally (ip) injected, was evaluated against audiogenic seizures in DBA/2 mice and against seizures induced by maximal electroshock (MES) and pentylenetetrazole (PTZ) in Swiss mice. Some of the new compounds 4 and 5 showed remarkable anticonvulsant activity, and their toxicity, as evidenced by the rotarod test, is lower than that of 1. The time course of anticonvulsant activity of derivatives 4b and 5b,c was studied and compared to that of 1 and 3b,c. Compounds 4a,b and 5a-c antagonize seizures induced by AMPA and kainate (KA) and their anticonvulsant activity is reversed by pretreatment with aniracetam. Using the patch-clamp technique, the capability of derivatives 3c, 4b, and 5c to antagonize KA-evoked currents in primary cultures of granule neurons was tested and compared with that of the parent compounds 1 and 1-(4-aminophenyl)-3, 4-dihydro-4-methyl-3-methylcarbamoyl-7,8-methylenedioxy-5H-2, 3-benzodiazepine (2, GYKI 53655).