Synthesis and cytotoxic activity of new acridine-thiazolidine derivatives

Overview of the New Bioactive Heterocycles as Targeting Topoisomerase Inhibitors Useful Against Colon Cancer

Colorectal cancer (CRC) is the third most common cancer globally, with high mortality. Metastatic CRC is incurable in most cases, and multiple drug therapy can increase patients' life expectancy by 2 to 3 years. Efforts are being made to understand the relationship between topoisomerase enzymes and colorectal cancer. Some studies have shown that higher expression of these enzymes is correlated to a poor prognosis for this type of cancer. One of the primary drugs used in the treatment of CRC is Irinotecan, which can be used in monotherapy or, more commonly, in therapeutic schemes such as FOLFIRI (Fluorouracil, Leucovorin, and Irinotecan) and CAPIRI (Capecitabine and Irinotecan). Like Camptothecin, Irinotecan and other compounds have a mechanism of action based on the formation of a ternary complex with topoisomerase I and DNA providing damage to it, therefore leading to cell death. Thus, this review focused on the principal works published in the last ten years that demonstrate a correlation between the inhibition of different isoforms of topoisomerase and in vitro cytotoxic activity against CRC by natural products, semisynthetic and synthetic compounds of pyridine, quinoline, acridine, imidazoles, indoles, and metal complexes. The results revealed that natural compounds, semisynthetic and synthetic derivatives showed potential in vitro cytotoxicity against several colon cancer cell lines, and this activity was often accompanied by the ability to inhibit both isoforms of topoisomerase (I and II), highlighting that these enzymes can be promising targets for the development of new chemotherapy against CRC. Pyridine analogs were considered the most promising for this study, while the evaluation of the real potential of natural products was limited by the lack of information in their work. Moreover, the complexes, although promising, presented as the main limitation the lack of selectivity.

Acridine as an Anti-Tumour Agent: A Critical Review

This review summarized the current breakthroughs in the chemistry of acridines as anti-cancer agents, including new structural and biologically active acridine attributes. Acridine derivatives are a class of compounds that are being extensively researched as potential anti-cancer drugs. Acridines are well-known for their high cytotoxic activity; however, their clinical application is restricted or even excluded as a result of side effects. The photocytotoxicity of propyl acridine acts against leukaemia cell lines, with C1748 being a promising anti-tumour drug against UDP-UGT's. CK0403 is reported in breast cancer treatment and is more potent than CK0402 against estrogen receptor-negative HER2. Acridine platinum (Pt) complexes have shown specificity on the evaluated DNA sequences; 9-anilinoacridine core, which intercalates DNA, and a methyl triazene DNA-methylating moiety were also studied. Acridine thiourea gold and acridinone derivatives act against cell lines such as MDA-MB-231, SK-BR-3, and MCF-7. Benzimidazole acridine compounds demonstrated cytotoxic activity against Dual Topo and PARP-1. Quinacrine, thiazacridine, and azacridine are reported as anti-cancer agents, which have been reported in the previous decade and were addressed in this review article.

Design and Synthesis of Acridine-Triazole and Acridine-Thiadiazole Derivatives and Their Inhibitory Effect against Cancer Cells

We report herein the design and synthesis of a series of novel acridine-triazole and acridine-thiadiazole derivatives. The newly synthesized compounds and the key intermediates were all evaluated for their antitumor activities against human foreskin fibroblasts (HFF), human gastric cancer cells-803 (MGC-803), hepatocellular carcinoma bel-7404 (BEL-7404), large cell lung cancer cells (NCI-H460), and bladder cancer cells (T24). Most of the compounds exhibited high levels of antitumor activity against MGC-803 and T24 but low toxicity against human normal liver cells (LO2), and their effect was even better than the commercial anticancer drugs, 5-fluorouracil (5-FU) and cis-platinum. Further, pharmacological mechanisms such as topo I, cell cycle, cell apoptosis, and neovascularization were all evaluated. Only a few compounds exhibited potent topo I inhibitory activity at 100 μM. In addition, the most active compounds with an IC₅₀ value of 5.52-8.93 μM were chosen, and they could induce cell apoptosis in the G2 stage of MGC-803 or mainly arrest T24 cells in the S stage. To our delight, most of the compounds exhibited lower zebrafish cytotoxicity but could strongly inhibit the formation of zebrafish sub-intestinal veins, indicating a potential for clinical application.

Acridine Based N-Acylhydrazone Derivatives as Potential Anticancer Agents: Synthesis, Characterization and ctDNA/HSA Spectroscopic Binding Properties

A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoisomerase I/II inhibitors, and their binding (calf thymus DNA—ctDNA and human serum albumin—HSA) and biological activities as potential anticancer agents on proliferation of A549 and CCD-18Co have been evaluated. The acridine-DNA complex 3b (-F) displayed the highest Kb value (Kb = 3.18 × 103 M−1). The HSA-derivatives interactions were studied by fluorescence quenching spectra. This method was used for the calculation of characteristic binding parameters. In the presence of warfarin, the binding constant values were found to decrease (KSV = 2.26 M−1, Kb = 2.54 M−1), suggesting that derivative 3a could bind to HSA at Sudlow site I. The effect of tested derivatives on metabolic activity of A549 cells evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT assay decreased as follows 3b(-F) > 3a(-H) > 3c(-Cl) > 3d(-Br). The derivatives 3c and 3d in vitro act as potential dual inhibitors of hTopo I and II with a partial effect on the metabolic activity of cancer cells A594. The acridine-benzohydrazides 3a and 3c reduced the clonogenic ability of A549 cells by 72% or 74%, respectively. The general results of the study suggest that the novel compounds show potential for future development as anticancer agents.

In vitro anti-Leishmania activity and molecular docking of spiro-acridine compounds as potential multitarget agents against Leishmania infantum

Leishmaniasis is an infectious disease with several limitations regarding treatment schemes. This work reports the anti-Leishmania activity of spiroacridine compounds against the promastigote (IC₅₀ = 1.1 to 6.0 µg / mL) and amastigote forms of the best compounds (EC₅₀ = 4.9 and 0.9 µg / mL) inLeishmania (L.) infantumand proposes an in-silico study with possible selective therapeutic targets for L. infantum. The substituted dimethyl-amine compound (AMTAC 11) showed the best leishmanicidal activity in vitro, and was found to interact with TryRandLdTopoI. comparisons with standard inhibitors were performed, and its main interactions were elucidated. Based on the biological assessment and the structure-activity relationship study, the spiroacridine compounds appear to be promisinganti-leishmaniachemotherapeutic agents to be explored.

s-Proline Covalented Silicapropyl Modified Magnetic Nanoparticles: Synthesis, Characterization, Biological and Catalytic Activity for the Synthesis of thiazolidin-4- ones

BACKGROUND

Thiazolidinoneones are important pharmaceutical compounds because of their biological activities. Several methods for the synthesis of 4-thiazolidinones are widely reported in the literature. The main synthetic routes to synthesize 1,3-thiazolidin-4-ones involve three components reaction between amine, a carbonyl compound and thioglycolic acid.

OBJECTIVE

s-Proline covalented silicapropyl modified magnetic nanoparticles (Fe3O4@SiO2-Pr @s-proline) were prepared. The antibacterial activity of synthesized nanoparticles against four bacterias was investigated that showed that 30 Mg/L of synthesized nanoparticles is a suitable concentration for bacterial inhibitory. Finally, the catalytic application of the synthesized s-Proline covalented silicapropyl modified magnetic nanoparticles for the synthesis of thiazolidinones and pyrazolyl thiazolidinones under stirring in aqueous media was evaluated. All of the synthesized organic compounds were characterized by mp, FT IR, 1H NMR, 13C NMR and elemental analysis.

MATERIALS AND METHODS

A combination of aldehyde (1.0 mmol), thioglycolic acid (1.0 mmol), various amines (1mmol) and 0.05 g Fe3O4@SiO2propyl@L-proline, were reacted at room temperature under stirring in 10 mL water. After completion of the reaction, as indicated by TLC (4:1 hexane: ethylacetate), the reaction mixture was filtered in the presence of an effective magnetic bar to separate the nanocatalyst. The nanocatalyst was washed with a mixture of hot EtOH: H2O two times. The crude products were collected and recrystallized from ethanol, if necessary.

RESULTS AND DISCUSSION

We present a novel avenue for the synthesis of thiazolidinones in the presence of Fe3O4@SiO2-Pr @s-proline under solvent-free conditions.

CONCLUSION

In conclusion, we have synthesized Fe3O4@SiO2-Pr@s-proline nanoparticles. Their biological activity against 4 bacterias was investigated. It released that 30Mg/L is the suitable concentration of synthesized nanoparticle for bacterial inhibitory. The catalytic efficiency of the catalyst was checked in the multicomponent reaction of various aldehyde, thioglycolic acid and various amines under stirring. This nanoparticle is a new organic-inorganic hybrid nanoparticle. The operational simplicity, the excellent yields of products, ease of separation and recyclability of the magnetic catalyst, waste reduction and high selectivity are the main advantages of this catalytic method. Furthermore, this new avenue is inexpensive and environmentally benign.

Design, synthesis, and cytotoxic activities of novel hybrids of parthenolide and thiazolidinedione via click chemistry

A series of novel parthenolide-thiazolidinedione hybrids have been synthesized via a click chemistry-mediated coupling between parthenolide and thiazolidinedione, and evaluated for their cytotoxic activities. The results indicated that all the hybrids showed moderate cytotoxic effects on human cancer cell lines, including human erythroleukemia cell line (HEL), prostate (PC3), and breast (MDA-MB-231) by MTT assay. In particular, compound VI-6 exhibited the best cytotoxic activities against the MDA-MB-231 cells with IC₅₀ value of 2.07 µM, which was about eight times more active than that of the original compound (PTL). These interesting results might be used to develop novel lead scaffolds for potential anticancer agents.

Synthesis, Spectroscopic, In-vitro and Computational Analysis of Hydrazones as Potential Antituberculosis Agents: (Part-I)

BACKGROUND

Since the last few decades, the healthcare sector is facing the problem of the development of multidrug-resistant (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) infections all over the world. Regardless of the current healthcare progress for the treatment of mycobacterial infections, we are still unable to control addition of every year 9 million new cases of tuberculosis (TB).

OBJECTIVE

We had an objective to synthesize some novel hydrazones, which were further subjected to characterization, Photoluminescence study, in vitro anti-mycobacterium testing and in silico ADMET predictions.

METHODS

Some new hydrazone derivatives have been successfully prepared by the condensation reaction in the present study. All the compounds were characterized by using FTIR, NMR, UV, Fluorescence spectroscopic techniques.

RESULTS

All our newly synthesized compounds showed strong electronic excitation at 292.6 - 319.0 nm and displayed more intense emissions in the 348 - 365 nm regions except compound 3i. The newly synthesized hydrazones 3a, 3b, 3f and 3g were found to be the most active compounds and showed MIC (Minimum inhibitory concentrations) values of 12.5 μg/mL.

CONCLUSION

In the realm of development of more potent, effective, safer and less toxic antituberculosis agents; our current study would definitely help the medicinal chemists to develop potent analogues containing hydrazine motifs in them.

Urazolium diacetate as a new, efficient and reusable Brønsted acid ionic liquid for the synthesis of novel derivatives of thiazolidine-4-ones

Urazolium diacetate catalyzed synthesis of new derivatives of 1,3-thiazolidine-4-ones (azo dispersive dyes family)viamulticomponent reaction of various aldehydes, thioglycolic acid and 4-aminoazobenzene under solvent-free reaction was reported.

Toxicity and Antitumor Activity of a Thiophene-Acridine Hybrid

The antitumor effects of thiophene and acridine compounds have been described; however, the clinical usefulness of these compounds is limited due to the risk of high toxicity and drug resistance. The strategy of molecular hybridization presents the opportunity to develop new drugs which may display better target affinity and less serious side effects. Herein, 2-((6-Chloro-2-methoxy-acridin-9-yl)amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]-thiophene-3-carbonitrile (ACS03), a hybrid thiophene–acridine compound with antileishmanial activity, was tested for toxicity and antitumor activity. The toxicity was evaluated in vitro (on HaCat and peripheral blood mononuclear cells) and in vivo (zebrafish embryos and acute toxicity in mice). Antitumor activity was also assessed in vitro in HCT-116 (human colon carcinoma cell line), K562 (chronic myeloid leukemic cell line), HL-60 (human promyelocytic leukemia cell line), HeLa (human cervical cancer cell line), and MCF-7 (breast cancer cell line) and in vivo (Ehrlich ascites carcinoma model). ACS03 exhibited selectivity toward HCT-116 cells (Half maximal inhibitory concentration, IC50 = 23.11 ± 1.03 µM). In zebrafish embryos, ACS03 induced an increase in lactate dehydrogenase, glutathione S-transferase, and acetylcholinesterase activities. The LD50 (lethal dose 50%) value in mice was estimated to be higher than 5000 mg/kg (intraperitoneally). In vivo, ACS03 (12.5 mg/kg) induced a significant reduction in tumor volume and cell viability. In vivo antitumor activity was associated with the nitric oxide cytotoxic effect. In conclusion, significant antitumor activity and weak toxicity were recorded for this hybrid compound, characterizing it as a potential anticancer compound.

Topoisomerase inhibition and albumin interaction studies of acridine-thiosemicarbazone derivatives

In the present study, acridine-thiosemicarbazones (ATD) derivatives were tested for their interaction properties with BSA through UV-Vis absorption and fluorescence spectroscopic studies. Both hyperchromic and hypochromic effects, as well as red or blue shifts were demonstrated after the derivatives were added to the BSA. Values for the binding constant (K_b) ranged from 1.62 × 10⁴ to 8.71 × 10⁵ M^-1 and quenching constant (K_SV) from 3.46 × 10² to 7.83 × 10³ M^-1 indicating a good affinity to BSA protein. Complementary, two compounds were selected to assess their inhibition activity against topoisomerase IIα enzyme, of which derivative 3a presented the best result. Moreover, to evaluate protein-ligand interactions, as well as the antitopoisomerase potential of these compounds, tests of molecular modeling were performed between all compounds using the albumin and Topoisomerase IIα/DNA complex. Finally, in silico studies showed that all derivatives used in this research displayed good oral bioavailability potential.

CD4+CD45RA-FOXP3low Regulatory T Cells as Potential Biomarkers of Disease Activity in Systemic Lupus Erythematosus Brazilian Patients

Heren, we analyzed Treg cells as potential biomarkers of disease activity in systemic lupus erythematosus (SLE) patients. Peripheral blood mononuclear cells from 30 SLE patients (15 active: SLEDAI > 6/15 SLE remission: SLEDAI< 6) and 15 healthy volunteers were purified. Treg immunophenotyping was performed using CD4, CD25, CD45, CD127, and FOXP3 markers. CD4⁺FOXP3⁺ Treg activation state was investigated based on CD45RA and FOXP3 expression. To increase the accuracy of our findings, a multivariate linear regression was performed. We showed a significant increase in the frequency of CD4⁺FOXP3⁺ Treg cells in SLE patients. However, unlike all other Treg cells phenotypes analyzed, only eTreg (CD4⁺FOXP3^highCD45RA^-) (p=0.01) subtype was inversely correlated with disease activity while Foxp3⁺nontreg (CD4⁺FOXP3^lowCD45RA^-) (p=0.003) exerted a direct influence in the outcome of the disease. Foxp3⁺nontreg cells were the most consistent SLE active indicator, confirmed by multiple linear regression analyses. In summary, our results demonstrate Foxp3⁺nontreg cells as new biomarkers in the search of an effective therapeutic strategy in SLE.

Design, synthesis and biological evaluation of some novel sulfonamide derivatives as apoptosis inducers

Several novel thiazolidinone and fused thiazolidinone derivatives bearing benzenesulfonamide moiety were synthesized and confirmed via spectral and elemental analyses. The newly synthesized compounds were evaluated for their cytotoxic activity on colorectal cancer cell line (Caco-2). All the synthesized compounds showed better activity than the reference standards (Doxorubicin and 5-FU). Investigation of the apoptotic activity of the most active compounds revealed that compounds 3a, 5a, 5c and 6c activate both caspase-3 and Fas-ligand in Caco-2 cell line. Compound 3a was the most active compound with caspase-3 concentration of 0.43 nmol/mL and Fas-ligand concentration of 775.2 pg/mL in treated Caco-2 cells. Compound 3a was radiolabeled with ^99mTc and its biodistribution pattern was evaluated in vivo using normal Swiss Albino mice. ^99mTc-compound 3a complex didn't exhibit any accumulation in any body organs except for its accumulation in the colon; target organ; where it showed 8.97 ± 1.35 %ID/g at 15min p. i. that elevated till 16.02 ± 2.43 %ID/g at 120min p. i.

Synthesis and in vitro anticancer activity of new 2-thioxo-oxazolidin-4-one derivatives

BACKGROUND

Oxazolidinones derivatives exhibit different biological properties, including anticancer activity. This work aimed to investigate the anticancer potential of five novel 2-Thioxo-oxazolidin-4-one derivatives.

METHODS

Cytotoxicity assays were performed in human peripheral blood mononuclear cells (PBMCs) from healthy individuals and seven tumor cell lines. Apoptosis detection and cell cycle were evaluated by flow cytometry and the expression of genes involved in cell death processes by Real-Time PCR.

RESULTS

All oxazolinedione derivatives were not cytotoxic in PBMCs. NB-5 showed the best results in cancer cells, inhibiting the growth of all tumor cell lines tested. NB-4 exhibited the highest cytotoxicity in Jurkat cells (IC₅₀=15.19μM) and NB-3 showed better anticancer effects in HL-60 (17.84μM). Only NB-4 significantly induced apoptosis in acute leukemia cells (p=0.001). All compounds caused a significant increase in expression of pro-apoptotic gene BID (p<0.05) and BECN1 (p<0.05). NB-3 significantly modulated the expression of RIPK3 (p=0.02) and DDIT3 (p=0.014), while NB-2 induced an increase of CDKN1A (p=0.03) and NB-4 induced PPARγ gene (p=0.0006).

CONCLUSION

NB-5 showed antitumor effects in solid and hematopoietic cancer cells, while other derivatives produced higher activity against hematopoietic cells. In acute leukemia cells, oxazolidinone derivatives modulated the expression of genes involved in apoptosis, ER stress, necroptosis and inflammation.

Design, synthesis and DNA-binding study of some novel morpholine linked thiazolidinone derivatives

The emergence of multiple drug resistance amongst bacterial strains resulted in many clinical drugs to be ineffective. Being vulnerable to bacterial infections any lack in the development of new antimicrobial drugs could pose a serious threat to public health. Here we report design and synthesis of a novel class of morpholine linked thiazolidinone hybrid molecules. The compounds were characterized by FT-IR, NMR and HRMS techniques. Susceptibility tests showed that most of the synthesized molecules were highly active against multiple bacterial strains. Compound 3f displayed MIC values which were better than the standard drug for most of the tested strains. DNA being a well defined target for many antimicrobial drugs was probed as possible target for these synthetic molecules. DNA-binding study of 3f with sm-DNA was probed through UV-vis absorption, fluorescence quenching, gel electrophoresis and molecular docking techniques. The studies revealed that compound 3f has strong affinity towards DNA and binds at the minor groove. The docking studies revealed that the compound 3f shows preferential binding towards A/T residues.

New thiazacridine agents: Synthesis, physical and chemical characterization, and in vitro anticancer evaluation

A series of new thiazacridine agents were synthesized and evaluated as antitumor agents, in terms of not only their cytotoxicity but also their selectivity. The cytotoxicity assay confirmed that all compounds showed cytotoxic activity and selectivity. The new compound, 3-acridin-9-ylmethyl-5-(5-bromo-1 H-indol-3-ylmethylene)-thiazolidine-2,4-dione (LPSF/AA29 – 7a), proved to be the most promising compound as it presents lower half-maximal inhibitory concentration (IC50) values (ranging from 0.25 to 68.03 µM) depending on cell lineage. In HepG2 cells, the lowest IC50 value was exhibited by 3-acridin-9-ylmethyl-5-(4-piperidin-1-yl-benzylidene)-thiazolidine-2,4-dione (LPSF/AA36 – 7b; 46.95 µM). None of the synthesized compounds showed cytotoxic activity against normal cells (IC50 > 100 µM). The mechanism of death induction and cell cycle effects was also evaluated. Flow cytometric analysis revealed that the compounds LPSF/AA29 – 7a and LPSF/AA36 – 7b significantly increased the percentage of apoptotic cells and induced G2/M arrest in the cell cycle progression. Therefore, these new thiazacridine derivatives constitute promising antitumor agents whose cytotoxicity and selectivity properties indicate they have potential to contribute to or serve as a basis for the development of new cancer drugs in the future.

Ultrastructural Assessment of 2-(acridin-9-ylmethylene)-N-phenylhydrazinecarbothioamide activity on human breast adenocarcinoma cells

The aim of the present study was to investigate ultrastructural changes induced by (Z)-2-(acridin-9-ylmethylene)-N-phenylhydrazinecarbothioamide (APHCA) treatment on human breast adenocarcinoma cancer cells MCF-7, besides the evaluation of phosphatidylserine externalization and DNA fragmentation in treated cells. Cell viability analysis demonstrated concentration and time-manner cytotoxicity. Treated MCF-7 cells did not expose phosphatidylserine residues to the external plasma membrane surface and DNA fragmentation was not visualized by electrophoresis. Light microscopy showed compromised cell density and presence of vacuolization after APHCA treatment with 60μM. Scanning and transmission electron microscopies revealed hallmarks of autophagy, namely the presence of membrane bebbling and autophagosomes, besides shrunken cells and cell debris in treated MCF-7 cells. However, more specific tests such as the quantification of mammalian autophagy proteins are necessary to determine the kind of death that is trigged by APHCA.

Synthesis of thiazolidine-2,4-dione derivatives: anticancer, antimicrobial and DNA cleavage studies

In the search of efficient anticancer agents, here, new 5-(4-alkylbenzyledene)thiazolidine-2,4-dione derivatives (5a-g) have been successfully synthesized and characterized and are evaluated for anticancer and antimicrobial activities using DNA cleavage studies. In vitro studies on anticancer activity of compound 5d (NSC: 768619/1) was done against the full panel of 60 human tumor cell lines. The five-level dose activity results revealed that, the compound 5d was active against all the cell lines, it has shown potential activity against leukemia SR (GI₅₀: 2.04 μM), non-small cell lung cancer NCI-H522 (GI₅₀: 1.36 μM), colon cancer COLO 205 (GI₅₀: 1.64 μM), CNS cancer SF-539 (GI₅₀: 1.87 μM), melanoma SK-MEL-2 (GI₅₀: 1.64 μM), ovarian cancer OVCAR-3 (GI₅₀: 1.87 μM), renal cancer RXF 393 (GI₅₀: 1.15 μM), prostate cancer PC-3 (GI₅₀: 1.90 μM), and breast cancer MDA-MB-468(GI₅₀: 1.11 μM). DNA cleavage studies revealed that at 50 μg/mL concentration, partial DNA digestion was observed and when the concentration is increasing to threefold (150 μg/mL), complete linear DNA digestion and partial supercoiled DNA digestion was observed. Further antimicrobial studies indicate that all the synthesized compounds except compound 5a possess prominent activity against all the screened microbial species. This study throws a ray of light in the field of anticancer drugs.

Rubrolide analogues and their derived lactams as potential anticancer agents

Analogues of rubrolides were synthesized and shown to be cytotoxic to several cancer cell lines and not toxic to L929 normal cells. The cytotoxicity involved the induction of cell death by apoptosis.

Synthesis, DNA Binding, and Antiproliferative Activity of Novel Acridine-Thiosemicarbazone Derivatives

In this work, the acridine nucleus was used as a lead-compound for structural modification by adding different substituted thiosemicarbazide moieties. Eight new (Z)-2-(acridin-9-ylmethylene)-N-phenylhydrazinecarbothioamide derivatives (3a-h) were synthesized, their antiproliferative activities were evaluated, and DNA binding properties were performed with calf thymus DNA (ctDNA) by electronic absorption and fluorescence spectroscopies. Both hyperchromic and hypochromic effects, as well as red or blue shifts were demonstrated by addition of ctDNA to the derivatives. The calculated binding constants ranged from 1.74 × 10(4) to 1.0 × 10(6) M(-1) and quenching constants from -0.2 × 10(4) to 2.18 × 10(4) M(-1) indicating high affinity to ctDNA base pairs. The most efficient compound in binding to ctDNA in vitro was (Z)-2-(acridin-9-ylmethylene)-N- (4-chlorophenyl) hydrazinecarbothioamide (3f), while the most active compound in antiproliferative assay was (Z)-2-(acridin-9-ylmethylene)-N-phenylhydrazinecarbothioamide (3a). There was no correlation between DNA-binding and in vitro antiproliferative activity, but the results suggest that DNA binding can be involved in the biological activity mechanism. This study may guide the choice of the size and shape of the intercalating part of the ligand and the strategic selection of substituents that increase DNA-binding or antiproliferative properties.

Inhibition of DNA topoisomerases I and II and growth inhibition of HL-60 cells by novel acridine-based compounds

HL-60 cancer cells were treated with a series of novel acridine derivatives (derivatives 1-4) in order to test the compounds' ability to inhibit both cancer cell growth and topoisomerase I and II activity. Binding studies of derivatives 1-4 with calf thymus DNA were also performed using a number of techniques (UV-Vis and fluorescence spectroscopy, thermal denaturation, linear dichroism and viscometry) to determine the nature of the interaction between the compounds and ctDNA. The binding constants for the complexes of the studied acridine derivatives with DNA were calculated from UV-Vis spectroscopic titrations (K=3.1×10(4)-2.0×10(3)M(-1)). Some of the compounds showed a strong inhibitory effect against Topo II at the relatively low concentration of 5μM. Topo I/II inhibition mode assays were also performed and verified that the novel compounds are topoisomerase suppressors rather than poisons. The biological activities of derivatives were studied using MTT assay and flow cytometric methods (detection of mitochondrial membrane potential, measurement of cell viability) after 24 and 48h incubation. The ability of derivatives to impair cell proliferation was tested by an analysis of cell cycle distribution.

A facile synthesis and antimicrobial activity evaluation of sydnonyl-substituted thiazolidine derivatives

Some new sydnonyl-substituted thiazolidine derivatives were synthesized in high yields by the modified Knoevenagel condensation of 3-aryl-4-formylsydnones with thiazolidine-2,4-dione and 2-thioxo-thiazolidine-4-one, respectively. All the synthesized thiazolidine derivatives were screened by paper-disc method to identify their antimicrobial activities against three bacteria viz. Staphylococcus aureus, Proteus vulgaris and Escherichia coli, and two fungal cultures viz. Aspergillus niger and Penicillium citrinum. The reference drugs were Norfloxacin and Griseofulvin, respectively. The screening data indicated that the tested sydnonyl-substituted thiazolidine derivatives exhibited no obvious antibacterial activity compared with the standard drug Norfloxacin. However, thiazolidine derivatives displayed significant antifungal activities against Penicillium citrinum and Aspergillus niger. Notably, all of the tested compounds showed growth inhibitory activity 1.5-4.4 times higher than that of the standard drug Griseofulvin against the two fungi.

Acridine and its derivatives: a patent review (2009 - 2013)

INTRODUCTION

Acridine derivatives have been extensively explored as potential therapeutic agents for the treatment of a number of diseases, such as cancer, Alzheimer's, and bacterial and protozoan infections. Their mode of action is mainly attributed to DNA intercalation and the subsequent effects on the biological processes linked to DNA and its related enzymes.

AREA COVERED

This review covers the relevant efforts in developing acridine derivatives with enhanced therapeutic potency and selectivity and as fluorescent materials, with particular focus on the newly patented acridine derivatives in 2009 - 2013, acridine drugs in clinical trials and preclinical studies, and other new derivatives that emerged in 2009 - 2013.

EXPERT OPINION

Thousands of acridines with therapeutic and biological activities or with photochemical properties have been developed. In addition, to modify the position and the nature of the substituent on the acridine core, more attention may be paid to the development of azaacridine or other heteroatom-substituted acridine derivatives and their synthesis methods to broaden the application of acridine derivatives. In cancer chemotherapy, the mode of action of acridine derivatives needs to be further studied. Efficient methods for identification and optimization of acridine derivatives to localize at the sites of disease need to be further developed. Moreover, acridine drugs may be combined with such bioactive agents as DNA repair proteins inhibitors to overcome tumor resistance and improve outcomes.

Novel tetrahydroacridine derivatives inhibit human lung adenocarcinoma cell growth by inducing G1 phase cell cycle arrest and apoptosis

Lung cancer is not only the most commonly diagnosed cancers worldwide but it is still the leading cause of cancer-related death. Acridine derivatives are a class of anticancer agents with the ability to intercalate DNA and inhibit topoisomerases. The aim of this study was to evaluate the effect of sixteen new tetrahydroacridine derivatives on the viability and growth of human lung adenocarcinoma cells. We compared anticancer activity of a series of eight compounds with 4-fluorobenzoic acid and eight compounds with 6-hydrazinonicotnic acid differed from each other in length of the aliphatic chain containing from 2 to 9 carbon atoms. Interestingly, tetrahydroacridine with 4-fluorobenzoic acid (compounds 9-16) showed higher anticancer activity than derivatives with 6-hydrazinonicotnic acid (compounds 1-8) and their efficacy was correlated with increasing number of carbon atoms in the aliphatic chain. The results showed that inhibition of cancer cell growth by the most effective compounds 15 and 16 was associated with induction of G1 phase cell cycle arrest followed by caspase-3 dependent apoptosis. Our findings suggest that tetrahydroacridine with 4-fluorobenzoic acid containing 8 and 9 carbon atoms may be potential candidate for treatment of lung cancer.

Recent advances in small organic molecules as DNA intercalating agents: synthesis, activity, and modeling

The interaction of small molecules with DNA plays an essential role in many biological processes. As DNA is often the target for majority of anticancer and antibiotic drugs, study about the interaction of drug and DNA has a key role in pharmacology. Moreover, understanding the interactions of small molecules with DNA is of prime significance in the rational design of more powerful and selective anticancer agents. Two of the most important and promising targets in cancer chemotherapy include DNA alkylating agents and DNA intercalators. For these last the DNA recognition is a critical step in their anti-tumor action and the intercalation is not only one kind of the interactions in DNA recognition but also a pivotal step of several clinically used anti-tumor drugs such as anthracyclines, acridines and anthraquinones. To push clinical cancer therapy, the discovery of new DNA intercalators has been considered a practical approach and a number of intercalators have been recently reported. The intercalative binding properties of such molecules can also be harnessed as diagnostic probes for DNA structure in addition to DNA-directed therapeutics. Moreover, the problem of intercalation site formation in the undistorted B-DNA of different length and sequence is matter of tremendous importance in molecular modeling studies and, nowadays, three models of DNA intercalation targets have been proposed that account for the binding features of intercalators. Finally, despite DNA being an important target for several drugs, most of the docking programs are validated only for proteins and their ligands. Therefore, a default protocol to identify DNA binding modes which uses a modified canonical DNA as receptor is needed.

Synthesis, DNA binding and topoisomerase I inhibition activity of thiazacridine and imidazacridine derivatives

Thiazacridine and imidazacridine derivatives have shown promising results as tumors suppressors in some cancer cell lines. For a better understanding of the mechanism of action of these compounds, binding studies of 5-acridin-9-ylmethylidene-3-amino-2-thioxo-thiazolidin-4-one, 5-acridin-9-ylmethylidene-2-thioxo-thiazolidin-4-one, 5-acridin-9-ylmethylidene-2-thioxo-imidazolidin-4-one and 3-acridin-9-ylmethyl-thiazolidin-2,4-dione with calf thymus DNA (ctDNA) by electronic absorption and fluorescence spectroscopy and circular dichroism spectroscopy were performed. The binding constants ranged from 1.46 × 10⁴ to 6.01 × 10⁴ M⁻¹. UV-Vis, fluorescence and circular dichroism measurements indicated that the compounds interact effectively with ctDNA, both by intercalation or external binding. They demonstrated inhibitory activities to human topoisomerase I, except for 5-acridin-9-ylmethylidene-2-thioxo-1,3-thiazolidin-4-one. These results provide insight into the DNA binding mechanism of imidazacridines and thiazacridines.

Novel cholinesterase modulators and their ability to interact with DNA

In the present work, an interaction of four cholinesterase modulators (1-4) with calf thymus DNA was studied via spectroscopic techniques (UV-Vis, fluorescent spectroscopy and circular dichroism). From UV-Vis spectroscopic analysis, the binding constants for DNA-pyridinium oximes complexes were calculated (K=3.5×10(4) to 1.4×10(5)M(-1)). All these measurements indicated that the compounds behave as effective DNA-interacting agents. Electrophoretic techniques proved that ligand 2 inhibited topoisomerase I at a concentration 5μM.

Synthesis and biological evaluation of (E)-1-(substituted)-3-phenylprop-2-en-1-ones bearing rhodanines as potent anti-microbial agents

Herein, we report the design, syntheses and in vitro anti-microbial activity of two series of rhodanines with chalcone moiety. Anti-microbial tests showed that some of the synthesized compounds exhibited good inhibition (MIC = 1-8 µg/mL) against multi-drug-resistant Gram-positive organisms, including methicillin resistant and quinolone-resistant Staphylococcus aureus, in which the compound 4g was found to be the most potent with minimum inhibitory concentration (MIC) value of 1 µg/mL against two methicillin-resistant S. aureus.