Melissa D'Ascenzio

Synthesis, anti-Candida activity, and cytotoxicity of new (4-(4-iodophenyl)thiazol-2-yl)hydrazine derivatives.

Novel (4-(4-iodophenyl)-thiazol-2-yl)hydrazine derivatives were assayed for their in vitro anti-Candida activity, compared to topical and systemic antifungal drugs, against twenty-seven clinical isolates. The presence of aliphatic chains or specific heteroaromatic rings on hydrazone moiety at position C2 and a 4-iodophenyl at C4 of the thiazole ring gave a promising inhibitory activity especially against Candida albicans and Candida krusei. The most active compounds have been also evaluated for their cytotoxicity and in association with clotrimazole for anti-Candida activity.

Cyclic tertiary sulfamates: Selective inhibition of the tumor-associated carbonic anhydrases IX and XII by N- and O-substituted acesulfame derivatives

Carbonic anhydrase (hCA) IX and XII isoforms are over-expressed both in primary and in metastatic cell lines of hypoxic tumors and are innovative targets for cancer diagnosis and treatment. On the basis of the importance of the pharmacophoric sulfamate moiety (bioisostere of the sulfonamide group) present in the structure of recent human CA inhibitors, we designed N-alkylated and O-alkylated derivatives of acesulfame, a cyclic tertiary sulfamate, assessing the inhibitory activity against the ubiquitous isoforms hCA I and II and the cancer-related isoforms hCA IX and XII. All derivatives were nanomolar inhibitors, with some of them possessing an outstanding selectivity towards the tumor-associated hCA IX and/or hCA XII isoforms.

Selective inhibition of human carbonic anhydrases by novel amide derivatives of probenecid: Synthesis, biological evaluation and molecular modelling studies

Novel amide derivatives of probenecid, a well-known uricosuric agent, were synthesized and evaluated as inhibitors of human carbonic anhydrases (hCAs, EC 4.2.1.1). The transmembrane isoforms (hCA IX and XII) were potently and selectively inhibited by some of them. The proposed chemical modification led to a complete loss of hCA II inhibition (K(i)s>10,000 nM) and enhanced the inhibitory activity against the tumour-associated hCA XII (compound 4 showed a K(i) value of 15.3 nM). The enzyme inhibitory data have also been validated by docking studies of the compounds within the active site of hCA XII.

Recent advances in the development of selective human MAO-B inhibitors: (Hetero)arylidene-(4-substituted-thiazol-2-yl)hydrazines

A large series of (4-substituted-thiazol-2-yl)hydrazine derivatives was synthesized in good yield and assayed for their in vitro human monoamine oxidase (hMAO) inhibitory activity and selectivity. Most of them showed inhibitory activity in the nanomolar range and hMAO-B selective inhibition higher than reference drugs, demonstrating our interest in this privileged scaffold. The structure-activity relationship of the different rings on the N1-hydrazine position indicated that a pyridine ring was preferred with the presence of electron-withdrawing substituents on the aryl group at C4 of the thiazole nucleus. The substituent on the α-carbon to the N1-hydrazine moiety (methyl or hydrogen) had a great influence on the activity and hMAO-B selectivity. Moreover, the reversibility of the enzyme inhibition for the best active compound was reported.

Synthesis and selective inhibition of human monoamine oxidases of a large scaffold of (4,5-substituted-thiazol-2-yl)hydrazones

A large class of (4,5-substituted-thiazol-2-yl)hydrazone derivatives (1–66) was synthesized in good yield (82–99%) and characterized by elemental analysis and 1H NMR studies. The compounds were assayed for their in vitro human monoamine oxidase inhibitory activity and selectivity. Most of them showed IC50 values in the micromolar range. Our aim was to evaluate the importance of a bulky group at C2, C4, and C5 positions of the thiazole nucleus in modulating the biological activity of this scaffold.

A Combined Crystallographic and Theoretical Study Explains the Capability of Carboxylic Acids to Adopt Multiple Binding Modes in the Active Site of Carbonic Anhydrases.

Carboxylates are the least investigated class of inhibitors of carbonic anhydrases (CAs). Here we explain the versatility of binding of these molecules to CAs by examining a new adduct of hCA II with N-carboxymethyl-saccharin.

Synthesis and pharmacological screening of a large library of 1,3,4-thiadiazolines as innovative therapeutic tools for the treatment of prostate cancer and melanoma

Antimitotic agents are widely used in cancer chemotherapy but the numerous side effects and the onset of resistance limit their clinical efficacy. Therefore, with the purpose of discovering more selective and efficient anticancer agents to be administered alone or in combination with traditional drugs, we synthesized a large library of 1,3,4-thiadiazoline analogues, maintaining the pharmacophoric structure of an antiproliferative compound known as K858: this is a new inhibitor of kinesin Eg5, able to induce the mitotic arrest in colorectal cancer cells and in xenograft ovarian cancer cells. We screened 103 compounds to assess their antiproliferative activity on PC3 prostate cancer cell line. Two derivatives, compounds 32 (corresponding to K858) and 33, have shown to be the most effective against prostate tumor cells and also towards two melanoma cell lines (SK-MEL-5 and SK-MEL-28) at low micromolar concentrations, confirming the pharmacological activity of this scaffold and revealing the potential role of 1,3,4-thiadiazolines in the management of cancer.

Synthesis and selective human monoamine oxidase B inhibition of heterocyclic hybrids based on hydrazine and thiazole scaffolds.

A new scaffold of hydrazothiazoles has been designed as monoamine oxidase (MAO) inhibitors combining the hydrazine moiety of iproniazid and the thiazole nucleus of glitazones, a class of peroxisome proliferator‐activated receptor (PPAR)γ agonists recently co‐crystallized with human MAO‐B. The resulting derivatives were synthesized and assayed to evaluate their in vitro activity against both the A and B isoforms of hMAO. All compounds were shown to be selective hMAO‐B inhibitors with IC50 values in the low micromolar/high nanomolar range. Such results suggest that the hydrazothiazole scaffold could be considered as an interesting pharmacophore for the future design of new lead compounds as coadjuvants for the treatment of neurodegenerative diseases.

Opening New Scenarios for Human MAO Inhibitors.

Despite the considerable interest in the search of new and potent human MAO inhibitors, an increasing number of research works deal with new therapeutic and analytical approaches regarding these molecules. Our interest was focused on the detailed analysis of (i) new pharmacological options for selective hMAO inhibitors; (ii) innovative analytical procedures to discover/screen hMAO inhibitors, and (iii) the recent possibility of using labeled hMAO inhibitors to unravel neurodegenerative diseases and drug distribution. All these three aspects could open new scenarios stimulating the interest of researchers in this field.

Synthesis, biological evaluation and quantitative structure-active relationships of 1,3-thiazolidin-4-one derivatives. A promising chemical scaffold endowed with high antifungal potency and low cytotoxicity

With reference to recent studies reporting on the various biological properties of the thiazolidinone scaffold, we synthesized more than a hundred compounds characterized by a 1,3-thiazolidin-4-one nucleus derivatised at the C2 with a hydrazine bridge linked to (cyclo)aliphatic or hetero(aryl) moieties, and their N-benzylated derivatives. These molecules were assayed as potential anti-Candida agents and they were shown to possess comparable, and in some cases higher biological activity than well-established topical and systemic antimycotic drugs (i.e. clotrimazole, fluconazole, ketoconazole, miconazole, tioconazole, amphotericin B). Compounds endowed with the lowest MICs underwent further testing in order to assess their cytotoxic effect (CC50) on Hep2 cells, which demonstrated their relative safety. Finally, QSAR and 3-D QSAR models were used to predict putative chemical modifications of the 1,3-thiazolidin-4-one scaffold in order to design new and potential more active compounds against Candida spp.