Novel Thiazolidine-2,4-dione-trimethoxybenzene-thiazole Hybrids as Human Topoisomerases Inhibitors.

Cancer is a complex and heterogeneous disease and is still one of the leading causes of morbidity and mortality worldwide, mostly as the population ages. Despite the encouraging advances made over the years in chemotherapy, the development of new compounds for cancer treatments is an urgent priority. In recent years, the design and chemical synthesis of several innovative hybrid molecules, which bring different pharmacophores on the same scaffold, have attracted the interest of many researchers. Following this strategy, we designed and synthetized a series of new hybrid compounds that contain three pharmacophores, namely trimethoxybenzene, thiazolidinedione and thiazole, and tested their anticancer properties on two breast cancer (MCF-7 and MDA-MB-231) cell lines and one melanoma (A2058) cell line. The most active compounds were particularly effective against the MCF-7 cells and did not affect the viability of the normal MCF-10A cells. Docking simulations indicated the human Topoisomerases I and II (hTopos I and II) as possible targets of these compounds, the inhibitory activity of which was demonstrated by the mean of direct enzymatic assays. Particularly, compound 7e was proved to inhibit both the hTopo I and II, whereas compounds 7c,d blocked only the hTopo II. Finally, compound 7e was responsible for MCF-7 cell death by apoptosis. The reported results are promising for the further design and synthesis of other analogues potentially active as anticancer tools.

Metal Complexes with Schiff Bases: Data Collection and Recent Studies on Biological Activities.

Metal complexes play a crucial role in pharmaceutical sciences owing to their wide and significant activities. Schiff bases (SBs) are multifaceted pharmacophores capable of forming chelating complexes with various metals in different oxidation states. Complexes with SBs are extensively studied for their numerous advantages, including low cost and simple synthetic strategies. They have been reported to possess a variety of biological activities, including antimicrobial, anticancer, antioxidant, antimalarial, analgesic, antiviral, antipyretic, and antidiabetic ones. This review summarizes the most recent studies on the antimicrobial and antiproliferative activities of SBs-metal complexes. Moreover, recent studies regarding mononuclear and binuclear complexes with SBs are described, including antioxidant, antidiabetic, antimalarial, antileishmanial, anti-Alzheimer, and catecholase activities.

Annona cherimola Mill. Leaf Extracts Affect Melanoma Cells Growth and Progression.

Cancer represents one of the major causes of mortality worldwide; indeed, 19.3 million new cases and almost 10.0 million deaths were estimated last year. Among the different type of cancers, malignant melanoma represents the most aggressive and deadly skin cancer. Unfortunately, the long-term efficacy of melanoma treatments is limited by the lack of clinical efficacy, onset of side effects and resistance. The latter is a major obstacle for the success of the melanoma therapy; thus, the exploration of new potent and safer anticancer agents is of great importance. Recently, numerous plant species, used for therapeutic purposes and containing various non-toxic nutraceuticals have been widely studied. Herein, we investigated the antioxidant and anticancer properties on melanoma cells of the ethanolic, methanolic and aqueous Annona cherimola leaf extracts (ACE, ACM and ACW, respectively). The ethanolic extract showed higher anticancer activity, mostly against the malignant A2058 melanoma cell line (IC50 = 5.6 ± 0.8 ng/mL), together with a very low activity on the normal cells. It blocks the melanoma cells migration process, and induces a clear disorganization of cytoskeleton, triggering cell apoptosis. Finally, some bioactive compounds were identified in the studied extracts.

N-Heterocyclic Carbene (NHC) Silver Complexes as Versatile Chemotherapeutic Agents Targeting Human Topoisomerases and Actin.

In recent years, the number of people suffering from cancer has risen rapidly and the World Health Organization and U.S. and European governments have identified this pathology as a priority issue. It is known that most bioactive anticancer molecules do not target a single protein but exert pleiotropic effects, simultaneously affecting multiple pathways. In our study, we designed and synthesized a new series of silver N-heterocyclic carbene (NHC) complexes [(NHC)2 Ag]+ [AgX2 ]- (X=iodide or acetate). The new complexes were active against two human breast cancer cell lines, MCF-7 and MDA-MB-231. These compounds showed multiple target actions as anticancer, by inhibiting in vitro the activity of the human topoisomerases I and II and interfering with the cytoskeleton dynamic, as also confirmed by in silico studies. Moreover, the antimicrobial activity of these silver complexes was studied against Gram-positive/negative bacteria. These dual properties provide a two-tiered approach, making these compounds of interest to be further deepened for the development of new chemotherapeutic agents.

Synthesis of a novel series of (Z)-3,5-disubstituted thiazolidine-2,4-diones as promising anti-breast cancer agents.

A novel series of (Z)-3,5-disubstituted thiazolidine-2,4-diones 4-16 has been designed and synthesized. Preliminary screening of these compounds for their anti-breast cancer activity revealed that compounds 5, 7, and 9 possess the highest anti-cancer activities. The anti-tumor effects of compounds 5, 7, and 9 were evaluated against human breast cancer cell lines (MCF-7 and MDA-MB-231) and human breast cancer cells. They were also evaluated against normal non-cancerous breast cells, isolated from the same patients, to conclude about their use in a potential targeted therapy. Using MTT uptake method, these three compounds 5, 7, and 9 blunt the proliferation of these cancer cells in a dose-dependent manner with an IC50 of 1.27, 1.50 and 1.31 µM respectively. Interestingly, using flow cytometry analysis these three compounds significantly mediated apoptosis of human breast cancer cells without affecting the survival of normal non-cancerous breast cells that were isolated from the same patients. Mechanistically, these compounds blunt the proliferation of MCF-7 breast cancer cells by robustly decreasing the phosphorylation of AKT, mTOR and the expression of VEGF and HIF-1α. Most importantly, compounds 5, 7, and 9 without affecting the phosphorylation and expression of these crucial cellular factors in normal non-cancerous breast cells that were isolated from the same patients. Additionally, using Western blot analysis the three compounds significantly (P < 0.05) decreased the expression of the anti-apoptotic Bcl-2 members (Bcl-2, Bcl-XL and Mcl-1) and increased the expression of the pro-apoptotic Bcl-2 members (Bak, Bax and Bim) in MCF-7, MDA-MB-231 and human breast cancer cells making these breast cancer cells susceptible for apoptosis induction. Taken together, these data provide great evidences for the inhibitory activity of these compounds against breast cancer cells without affecting the normal breast cells.

Benzothienoquinazolinones as new multi-target scaffolds: Dual inhibition of human Topoisomerase I and tubulin polymerization.

3-(Alkyl(dialkyl)amino)benzothieno[2,3-f]quinazolin-1(2H)-ones (4-9) have been designed using Ellipticine structure as a model, replacing the carbazole core and the pyridine ring with a dibenzothiophene and a pyrimidine moiety, respectively. New benzothienoquinazolinones (4-9) have been synthesized by a simple one-pot reaction employing 3-aminodibenzothiophene as starting material. The benzothienoquinazolinones obtained (4-9), were evaluated for their anticancer activity against two breast cancer cell lines, MDA-MB-231 and MCF-7. The results revealed that compounds 4 and 7 presented a good antitumor activity toward the triple negative MDA-MB-231, without cytotoxicity against non-tumoral cells. Furthermore, the compounds 4 and 7 can be considered important molecular multi-target tools for their dual inhibition of different cellular proteins, i.e. Tubulin and human Topoisomerase I, involved in relevant cellular processes, as predicted by in silico studies and demonstrated by in vitro assays (for compound 4).

Anticancer and Anti-Inflammatory Activities of Some New Pyrazolo[3,4-b]pyrazines.

New derivatives of pyrazolo[3,4-b]pyrazines and related heterocycles were synthesized using 5-amino-3-methyl-4-nitroso-1-phenyl-pyrazole (1) as a starting material. The 5-acetyl derivative 15 was shown to be a useful key intermediate for the synthesis of several derivatives of pyrazolopyrazines. Some of the prepared compounds were evaluated for their anti-inflammatory and anti-breast cancer MCF-7 cell line activities. SAR study showed that compounds 15 and 29 exhibited remarkable anti-inflammatory activity, where 15 showed the same activity as that of the reference drug indomethacin. On the other hand, compounds 25i, 25j showed very significant inhibitory activity (p < 0.001) against MCF-7 breast cancer cell line.

Antitrypanosomatid Pharmacomodulation at Position 3 of the 8-Nitroquinolin-2(1H)-one Scaffold Using Palladium-Catalysed Cross-Coupling Reactions.

An antikinetoplastid pharmacomodulation study at position 3 of the recently described hit molecule 3-bromo-8-nitroquinolin-2(1H)-one was conducted. Twenty-four derivatives were synthesised using the Suzuki-Miyaura cross-coupling reaction and evaluated in vitro on both Leishmania infantum axenic amastigotes and Trypanosoma brucei brucei trypomastigotes. Introduction of a para-carboxyphenyl group at position 3 of the scaffold led to the selective antitrypanosomal hit molecule 3-(4-carboxyphenyl)-8-nitroquinolin-2(1H)-one (21) with a lower reduction potential (-0.56 V) than the initial hit (-0.45 V). Compound 21 displays micromolar antitrypanosomal activity (IC50 =1.5 µm) and low cytotoxicity on the human HepG2 cell line (CC50 =120 µm), having a higher selectivity index (SI=80) than the reference drug eflornithine. Contrary to results previously obtained in this series, hit compound 21 is inactive toward L. infantum and is not efficiently bioactivated by T. brucei brucei type I nitroreductase, which suggests the existence of an alternative mechanism of action.

Novel resources of Taxol from endophytic and entomopathogenic fungi: Isolation, characterization and LC-Triple mass spectrometric quantification.

This work presents a second-to-none method for Taxol isolation from the Endophytic fungus Cladosporium sphaerospermum (AUMC 6896) and the Entomopathogenic fungus Metarizium anisopliae (AUMC 5130). The extracts were analyzed by high performance liquid chromatography (HPLC) and Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) using positive electrospray ionization (ESI) in the multiple reaction monitoring (MRM) mode. This is rapid, consistent, reproducible, accurate, and sensitive for quantifying Taxol across multiple samples. The yield of crude Taxol product obtained from Potato Dextrose broth (PDB) medium inoculated with Cladosporium sphaerospermu and Metarizium anisopliae was found to be 3.732, and 0.0023 µg L-1 respectively. The yield can be improved by adding ammonium acetate or salicylic acid to the culture broth. Addition of ammonium acetate (AA) (20 mg L-1) to culture media resulted in an increase of Taxol yield to 30.365 and 27.289 µg L-1 respectively. Production of Taxol was 29.844 and 67.254 µg L-1 for the two fungus species when ammonium acetate was substituted by 90 mg L-1 salicylic acid (SA). Adding both AA (20 mg L-1) and SA (90 mg L-1) to the culture media resulted in an increase of the Taxol yield to 4.054 and 116.373 µg L-1 respectively. Our proposed analytical method offers very fast (3 min) quantitation of Taxol in comparison with other published methods. These findings represent a new bioprospecting of the endophytic fungi that may serve as a potential material for the production of Taxol for anticancer treatment.

Discovery of new hit-molecules targeting Plasmodium falciparum through a global SAR study of the 4-substituted-2-trichloromethylquinazoline antiplasmodial scaffold.

From 4 antiplasmodial hit-molecules identified in 2-trichloromethylquinazoline series, we conducted a global Structure-Activity relationship (SAR) study involving 26 compounds and covering 5 molecular regions (I - V), aiming at defining the corresponding pharmacophore and identifying new bioactive derivatives. Thus, after studying the aniline moiety in detail, thienopyrimidine, quinoline and quinoxaline bio-isosters were synthesized and tested on the K1 multi-resistant P. falciparum strain, along with a cytotoxicity evaluation on the human HepG2 cell line, to define selectivity indecies. SARs first showed that thienopyrimidines and quinolines were globally more cytotoxic, while quinoxaline analogs appeared as active as- and less cytotoxic than their quinazoline counterparts. Such pharmacomodulation in quinoxaline series not only provided a new antiplasmodial reference hit-molecule (IC50 = 0.4 µM, selectivity index = 100), but also highlighted an active (IC50 = 0.4 µM) and quite selective (SI = 265) synthesis intermediate.

Synthesis, Anti-inflammatory and Antibacterial Activities of Novel Pyrazolo[4,3-g]pteridines.

A novel series of 6-substituted pyrazolo[3,4-g]pteridines 2-9 and pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pteridin-2(3H)-one (thione) 10 and 11 was synthesized using the starting compound 3,7-dimethyl-1-phenylpyrazolo[4',3':5,6]pyrazino[2,3-d][1,3]oxazin-5(1H)-one 2. The structure of the newly synthesized compounds was elucidated by IR, (1)H-NMR, (13)C-NMR, mass spectroscopy and elemental analyses. The anti-inflammatory activity of all the newly synthesized compounds was evaluated using the carrageenan-induced paw oedema test in rats using indomethacin as the reference drug. Compound 11 and the two derivatives 7f and 8b were the most active compounds, showing an activity comparable to indomethacin. Also, the synthesized compounds were evaluated for their antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) using chloramphenicol as control. The pyrazolotriazolopteridin-2-thione 11, 6-hydroxyethyl- 6a, 6-(4-nitrophenyl)-7g, and 6-(phenylamino) 8b derivatives were found to be the most active compounds against the Gram-positive species. None of them showed any activity against Gram-negative species.

3-(Dipropylamino)-5-hydroxybenzofuro[2,3-f]quinazolin-1(2H)-one (DPA-HBFQ-1) plays an inhibitory role on breast cancer cell growth and progression.

A series of unknown 3-(alkyl(dialkyl)amino)benzofuro[2,3-f]quinazolin-1(2H)-ones 4-17 has been synthesized as new ellipticine analogs, in which the carbazole moiety and the pyridine ring were replaced by a dibenzofuran residue and a pyrimidine ring, respectively. The synthesis of these benzofuroquinazolinones 4-17 was performed in a simple one-pot reaction using 3-aminodibenzofuran or its 2-methoxy derivative, as starting materials. From 3-(dipropylamino)-5-methoxybenzofuro[2,3-f] quinazolin-1(2H)-one (13), we prepared 3-(dipropylamino)-5-hydroxybenzofuro[2,3-f]quinazolin-1(2H)-one (18), referred to as DPA-HBFQ-1. The cytotoxic activities of all the synthesized compounds, tested in different human breast cancer cell lines, revealed that DPA-HBFQ-1 was the most active compound. In particular, the latter was able to inhibit anchorage-dependent and -independent cell growth and to induce apoptosis in estrogen receptor alpha (ERα)-positive and -negative breast cancer cells. It did not affect proliferation and apoptotic responses in MCF-10A normal breast epithelial cells. The observed effects have been ascribed to an enhanced p21(Cip1/WAF1) expression in a p53-dependent manner of tumor suppressor and to a selective inhibition of human topoisomerase II. In addition, DPA-HBFQ-1 exerted growth inhibitory effects also in other cancer cell lines, even though with a lower cytotoxic activity. Our results indicate DPA-HBFQ-1 as a good candidate to be useful as cancer therapeutic agent, particularly for breast cancer.

Crystallographic study and biological evaluation of 1,4-dimethyl-N-alkylcarbazoles.

The 9-(bromoalkyl)-1,4-dimethyl-9H-carbazole (2a-d) derivatives, characterized by the presence of five or seven methylenic spacer groups bonded to the carbazole nitrogen, have been synthesized from the corresponding 1,4- dimethyl-9H-carbazole and appropriate dibromoalkane following a general synthetic method. All the prepared species have been fully characterized by means of IR, and (1)H and (13)C NMR spectroscopy, GC-MS and Elemental analysis. Good crystals of the 2c have been obtained and the crystal structure has been solved by means of X-ray diffractometry. In order to study the cytotoxic effect of 2a, 2b, 2c, 2d carbazole derivatives on A2780 ovarian cancer cells, we performed MTT assay after exposure of this cell population to those compounds in a concentration range from 1 to 10µM. Finally, we want to verify whether the cytotoxic effect of the 2c carbazole is mediated by apoptotic mechanisms, by performing chromatin condensation assay on the A2780 cell cultures upon the carbazole treatment at concentration of 10 µM for 72h. All together our data demonstrate that carbazole derivatives exert inhibitory effects on ovarian cancer cell growth, highlighting a stronger and a dose-dependent anti proliferative activity displayed by 2c carbazole, designating this compound, as a better candidate in the treatment of human ovarian cancer.

Indenopyrazole oxime ethers: synthesis and ß1-adrenergic blocking activity.

This paper reports the synthesis and cardiac activity of new ß-blockers derived from (Z/E)-indeno[1,2-c]pyrazol-4(1H)-one oximes (5a,b). The latter compounds were allowed to react with epichlorohydrin, followed by reacting the oxiranyl derivatives formed (6a,b) with some aliphatic amines to give the target compounds (Z/E)-1-phenyl-1H-indeno[1,2-c]pyrazol-4-one O-((2-hydroxy-3-(substituted amino)propyl)oxime (7a-c) and (Z/E)-1-methyl-1H-indeno[1,2-c]pyrazol-4-one O-((2-hydroxy-3-(substituted amino)propyl)oxime (8a-c). These final products 7a-c and 8a-c were evaluated for their ability to modulate the cardiac performance of a prototype mammalian heart. The results showed that, out of these molecules tested, 7b elicits a more potent depressant effect on contractility and relaxation, and competitively antagonizes ß1-adrenergic receptors.

Synthesis and anticonvulsant activity of some new pyrazolo[3,4-b]pyrazines and related heterocycles.

A series of new pyrazolo[3,4-b]pyrazines containing, 1,2,4-oxadiazolyl, thiadiazolyl, imidazothiadiazolyl, thiazolidinonyl, substituents and other different substituents, was synthesized using 1,6-diphenyl-3-methyl-lH-pyrazolo[3,4-b]pyrazine-5-carbonitrile (2) as a starting material. Some of the newly prepared compounds were evaluated for their anticonvulsant activity. Compounds 9a, 13a-d and 14a at a dose of 10mg/kg showed very significant anticonvulsant activity and increased the latency time of PTZ-induced tonic seizures. Compound 9b showed significant effect.

Crystal structure of 2-[12-methyl-14-phenyl-10,13,14,16-tetra-aza-tetra-cyclo[7.7.0.0(2,7).0(11,15)]hexa-deca-1(16),2,4,6,9,11(15),12-heptaen-8-yl-idene]propandi-nitrile.

In the title mol-ecule, C22H12N6, the fused tetracyclic core shows a small lengthwise twist as indicated by the dihedral of 2.7 (2)° between the outer rings. In the crystal, mol-ecules stack along the b-axis direction via offset π-stacking [centroid-centroid distances = 3.5282 (13) and 3.5597 (14) Å] with the stacks weakly associated through C-H⋯N hydrogen bonds. The phenyl ring is rotationally disordered over two orientations with an occupancy ratio of 0.516 (4):0.484 (4).

Crystal structure of (E)-4-{[2-(2,4-di-nitro-phen-yl)hydrazin-1-yl-idene]meth-yl}-3-methyl-1-phenyl-5-(1H-pyrrol-1-yl)-1H-pyrazole.

The title compound, C21H17N7O4, is in an 'extended' conformation aided by an intra-molecular N-H⋯O hydrogen bond. The pyrazole ring makes dihedral angles of 29.17 (6), 65.47 (4) and 9.91 (7)°, respectively, with the phenyl, pyrrole and benzene rings. In the crystal, mol-ecules are connected by pairs of N-H⋯O and C-H⋯O hydrogen bonds, forming inversion dimers which associate into ribbons running along the b axis through complementary C-H⋯O inter-actions.

Synthesis and evaluation of cytotoxic activities of new guanidines derived from carbazoles.

Several new alkylguanidines derived from carbazole have been synthesized in a simple one-pot reaction starting from 3-aminocarbazole derivatives. The aminocarbazoles were reacted with ethoxycarbonylisothiocyanate, to give thiourea intermediates, followed by the addition of an alkylamine and HgCl2 to give ethoxycarbonylguanidine intermediates. The reaction mixture was then heated at 160 °C to give the N-(1,4-dimethyl-9H-carbazol-3-yl)-N'-alkylguanidines. The cytotoxic activity of all the synthesized guanidines was evaluated against different cell lines.

Enhanced cellular uptake by "pharmaceutically oriented devices" of new simplified analogs of Linezolid with antimicrobial activity.

The aim of the present study was to enhance cellular uptake of simplified analogs of Linezolid by their incorporation into suitable delivery devices in order to improve the antimicrobial activity of these novel synthesized oxazolidin-2-one derivatives. The oxazolidin-2-one derivatives were synthesized by developing a rather simple one-pot reaction starting from oxiranylmethanol and several primary amines. Three delivery devices were prepared by following different synthetic approaches, such as single-step free radical grafting, precipitation polymerization and nano-emulsion. Finally, the antimicrobial activity of the novel synthesized compounds, without any vehicle and after their incorporation into the delivery devices, was evaluated against Escherichia coli and Saccharomyces cerevisiae by performing time-kill analyses. The synthesized oxazolidinones exhibited modest antimicrobial activity against E. coli and S. cerevisiae (MIC 16 µg/mL). A good activity was, instead, highlighted after their incorporation into the prepared delivery devices (lecithin-based nano-emulsion, poly(N-vinyl-pyrrolidone)-methacrylic acid grafted copolymer and spherical polymeric nanoparticles) (MIC≤4 µg/mL). The incorporation into suitable vehicles, indeed, reduced by 4 times the normal MICs of the newly synthesized oxazolilidin-2-ones and represents an effective strategy to overcome cellular penetration constraints.

First synthesis and biological evaluation of indeno[2,1-e]pyrazolo[3,4-b]pyrazin-5-one and related derivatives.

The synthesis of indeno[2,1-e]pyrazolo[3,4-b]pyrazin-5-one was achieved by intramolecular Friedel-Crafts reaction of the acid chloride 3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b] pyrazine-5-carboxylic acid chloride (4) using AlCl3 in boiling CS2. Compound 4 proved to be a versatile compound for the synthesis of several Indenopyrazolopyrazinone derivatives. The antibacterial and antifungal activities of selected derivatives were evaluated.