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The datasets contain the results of determining the minimum inhibitory concentration of C-1330 derivatives (IKE9-IKE14) against C. albicans ATCC 10231, C. glabrata ATCC 90030, C. krusei ATCC 6258 and C. parapsilosis ATCC 22019 by the modified M27-A3 specified by the CLSI.

Acridone and its derivatives have potential application as emitters for highly efficient blue organic light-emitting diodes (OLEDs). In this paper, we demonstrated ultrafast access of a solvent-independent singlet-triplet equilibrium state in acridone solutions by using femtosecond time-resolved spectroscopy. Our spectral data show that due to highly effective forward and reverse intersystem crossing (both kISC and krISC over 1010 s-1), a singlet-triplet equilibrium state is always populated in acridone in all solvents studied. However, the lifetimes of the equilibrium state varied a lot in different solvent environments and the final decay pathway of this state can switch between high quantum yield fluorescence emission and further internal conversion to the lowest triplet state. These findings provide direct experimental evidence to understand the distinct photophysical behaviors of acridone and also provide guidance for further design of acridone and its derivatives as blue OLED emitters.

A modular and flexible three-step synthetic strategy has been developed for the synthesis of acridone natural products of biological significance. The tetracyclic core of acridone derivatives has been achieved efficiently in high yield from commercially available anthranilic acid and phenol derivatives via condensation reaction, followed by regioselective annulation. Acridone alkaloids acronycine and noracronycine are synthesized in improved overall yields in fewer steps than the previously reported approaches. The method has further been used for the synthesis of atalaphyllidine and 5-hydroxynoracronycine in excellent yields for the first time. Moreover, the synthetic utility of the present strategy has been showcased by the synthesis of oxa and thia analogues of acronycine alkaloid.

Six pyrophosphate analogues are prepared from zerumbone, murrayafoline A, acridone, and 4-hydroxycoumarin via 1,3-dipolar cycloaddition reactions. Their in vitro cytotoxic activity is evaluated against HepG2, LU-1, and HeLa cancer cell lines. Among them, diisopropyl ((ethoxy((4-((1-methoxy-3-methyl-9 H-carbazol-9-yl)methyl)-1 H-1,2,3-triazol-1-yl)methyl)phosphoryl)methyl)phosphonate (6a) and diisopropyl ((ethoxy((4-(((3-methyl-9 H-carbazol-1-yl)oxy)methyl)-1 H-1,2,3-triazol-1-yl)methyl)phosphoryl)methyl)phosphonate (6b) are found to show activity against HepG2, LU-1, and HeLa cancer cell lines, with IC50 values ranging from 7.31 to 17.88 μM.

Aims: To develop anti-cancer active pharmaceutical intermediates. Background: Acridone derivatives possess a wide range of pharmacological activities: 1) they intercalate DNA and 2) form a covalent bond with DNA. Objective: To screen in vitro anti-cancer activity against Cdc25b and SHP1 of new acridone derivatives and preliminary study on the structure-activity relationship. Materials and Methods: The synthesis of new acridone derivatives and in vitro evaluation of their anti-cancer activity on Cdc25b and SHP1 was achieved. Natural products that contain acridine structures, such as cystodytin A and acronycine, are isolated from certain marine (tunicates & ascidians, sponges, sea anemones) and plant (bark of Australian scrub ash tree) species. Herein, we report the efficient one-pot green synthesis of twelve novel 3,4-dihydro-1 (2H) acridone derivatives, using montmorillonite K10 as the catalyst and iron/citric acid in water. Also, their inhibitory activity against Cdc25B and SHP1 is examined, in which specific derivatives show enhanced inhibitory activity compared to others. Results and Discussion: Twelve new acridone derivatives were prepared, starting from 2-nitrobenzaldehyde derivatives and 1, 3-cyclohexanedione derivatives, which exhibited substantial anti-cancer activity against Cdc25b and SHP1 cells. Conclusion: Preliminary studies on the structure-activity relationship have shown the influence of the structural parameters and, in particular, the nature of the substituent on aromatic ring structure and cyclohexanone. Other: Further study on the structure-activity relationship is required.

A novel electroanalytical process for sucralose determination has been theoretically suggested. Sucralose is immobilized over an acridine derivative 9-9´-diacridyl, yielding a quaternary salt, which is thereby gradually electrochemically reduced to an N-N´-disubstituted acridone derivative. The correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis, and this analysis has shown the high probability of the oscillatory and monotonic instabilities, due to the double electric layer structure changes during all of the stages of the process. Nevertheless, it also confirms the efficiency of 9-9´-diacridyl-modified electrode for sucralose determination in an electroanalytical system, which may be coupled with a fluorescent indicator. DOI: http://dx.doi.org/10.17807/orbital.v13i3.1584

Crown ethers containing an acridone or an acridine unit are successfully applied opto- and electrochemical cation sensors. The heteroaromatic unit of these macrocycles can be in different forms during the applications, which have a strong influence on the sensing behavior. Moreover, in the case of acridono-macrocycles a prototropic equilibrium takes place upon complexation, which is effected by the physicochemical characteristics. A Pb2+-selective acridono-18-crown-6 ether and its 9-phenylacridino-analogue were used as model compounds for comparing the different forms of the heterocyclic units of these sensor molecules. Since in most practical sensor applications of the fluorescent hosts a non-neutral aqueous medium is present, studies on complexation and signaling were carried out from the aspect of the relationship among protonation, coordinating ability, complex stability and tautomeric equilibrium. A strong interdependence among these factors was found and limitations of using unsubstituted acridino- and acridono-sensor molecules in comparison with their 9-substituted-acridino-analogues were discussed. This study will hopefully serve as a useful standpoint for future development of ionophore-based sensors containing an acridone or an acridine unit.

A simple and mild protocol towards the synthesis of new 1,2,3-triazole compounds derived from acridone has been developed via regiospecific 1,3-dipolar cycloaddition reaction between 10-(prop-2-yn-1-yl)acridone derivatives and aromatic azides using CuI as a catalyst. The cycloaddition reaction has been performed using conventional as well as microwave-assisted methods. Microwave-assisted synthesis caused a significant reduction in the reaction times and improvement in the yields of all the synthesized compounds compared with the conventional method. The structure of the 1,4-disubstituted 1,2,3-triazoles has been elucidated by IR, HRMS, 1H-NMR, 13C-NMR, and 2D NMR (1H-13C HMBC, 1H-1H COSY, and 1H-1H NOESY) spectroscopies.

Acridone derivatives, which have been shown to have in vitro and in vivo activity against Plasmodium spp, inhibit Toxoplasma gondii proliferation at picomolar concentrations. Using enzymatic assays, we show that acridones inhibit both T. gondii cytochrome bc1 and dihydroorotate dehydrogenase and identify acridones that bind preferentially to the Qi site of cytochrome bc1. We identify acridones that have efficacy in a murine model of systemic toxoplasmosis. Acridones have potent activity against T. gondii and represent a promising new class of preclinical compounds.

An aromatic alkaloid-rich 'absolute' extract from inhibited at 62.5 μg.mL and at 500 μg.mL A loss of activity upon fractionation indicated possible synergistic effects. Three new acridones, gossweicridone A ( ), B ( ) and C ( ) and known compounds from the extract were inactive. Combinations of compounds showed that a sub-fraction containing mixtures of minor compounds with ( )-caryophyllene augmented activity by 50-folds, with MIC values of 19.6 μg.mL for and 375.0 μg.mL for , demonstrating potent ΣFIC values of 0.02 and 0.375 respectively. From the active sub-fraction, three compounds were assigned as tecleanatalensine B, 13 -hydroxy-9 ,11 ,15 -octadecatrienoic acid and normelicopine. In combination with ( )-caryophyllene they separately demonstrated MIC values of 18 μg.mL , 34 μg.mL and 16 μg.mL respectively against . The synergistic combinations were more potent with addition of pheophytin A, suggesting that the synergistic antifungal effect of the extract is multi-layered.

It is strongly desired for thermally activated delayed fluorescence (TADF) compounds to possess a high rate constant of radiation (KR) and a high rate constant of reverse intersystem crossing (KRISC) simultaneously. A novel TADF compound, 3,6-di(10H-phenoxazin-10-yl)-10-phenylacridin-9(10H)-one (3,6-DPXZ-AD), is designed by attaching phenoxazine as the electron donor at the 3,6-sites of acridin-9(10H)-one as the acceptor. The unique sp2-hybridization of the nitrogen atom of the acridone ring leads to the quasi-equatorial conformation and the high molecular rigidity of 3,6-DPXZ-AD, which suppress conformation relaxation and finally generate a high KR of 1.4 × 107 s−1. The phosphorescence of 3,6-DPXZ-AD with unexpected higher energy than its fluorescence is proved to originate from the intermolecular through-space charge transfer state (TSCT) and the locally excited triplet states (3LE). Due to the multichannel RISC process from the TSCT and 3LE states to the 1CT state, a high KRISC of 1.1 × 106 s−1 is realized simultaneously. 3,6-DPXZ-AD shows a short TADF lifetime of 1.6 μs and a high fluorescence quantum yield of 94.9%. The yellow organic light-emitting diode with 3,6-DPXZ-AD as the doped emitter exhibits excellent performance with a low turn-on voltage of 2.2 V, an external quantum efficiency of 30.6% and a power efficiency of 109.9 lm W−1, being among the best values ever reported for acridone based materials.

Computed nucleus-independent chemical shifts (NICS), contour plots of isotropic magnetic shielding (IMS), and gauge-including magnetically induced current (GIMIC) plots suggest that polarization of the π-system of acridones may perturb the numbers and positions of Clar sextet rings. Decreasing numbers of Clar sextets are connected to experimental observations of a narrowing HOMO-LUMO gap and increased charge mobility in solid-state assemblies of quinacridone and epindolidione.

In comparison with green and red OLEDs, which have been well developed with satisfactory electroluminescence (EL) performances, high-efficiency blue OLEDs still need further exploration. Herein, by reasonably strengthening the rigidity of molecules, three new sky-blue thermally activated delayed fluorescence molecules based on electron-withdrawing acridone and electron-donating acridine derivatives are designed and synthesized. Their crystal and electronic structures, thermal stabilities, electrochemical behaviors and photophysical properties are systemically investigated. The results show that these molecules have high thermal and electrochemical stabilities and exhibit aggregation-induced emission and eminent sky-blue delayed fluorescence with emission peaks at 480–502 nm and high fluorescence quantum yields of 78–94% in doped films. Their OLEDs exhibit sky-blue EL emissions with peaks at 482–492 nm, and achieve excellent external quantum efficiencies of 21.8–26.8%. These results indicate that the new sky-blue delayed fluorescence molecules hold good potential as light-emitting materials for OLEDs.

The oxidative demethylation of ortho-dimethoxyacridone with ceric ammonium nitrate (CAN) regioselectively furnished an ortho-quinone leaving a methoxyl group unreacted, which further condensed with aromatic ortho-diamines to afford angularly fused π-extended acridone derivatives. Crystallographic analysis reveals the distinct manner of molecular packing in the crystals according to the dimension of π-extension. The benzene at the turning point possesses a shorter outer bond and a longer inner bond, which affects molecular conjugation and results in weakened aromaticity.

A total of 21 novel xanthone and acridone derivatives were synthesized using the reactions of 1,2,4-triazine derivatives with 1-hydroxy-3-methoxy-10-methylacridone, 1,3-dimethoxy-, and 1,3-dihydroxanthone, followed by optional dihydrotiazine ring aromatization. The synthesized compounds were evaluated for their anticancer activity against colorectal cancer HCT116, glioblastoma A-172, breast cancer Hs578T, and human embryonic kidney HEK-293 tumor cell lines. Five compounds (7a, 7e, 9e, 14a, and 14b) displayed good in vitro antiproliferative activities against these cancer cell lines. Compounds 7a and 7e demonstrated low toxicity for normal human embryonic kidney (HEK-293) cells, which determines the possibility of further development of these compounds as anticancer agents. Annexin V assay demonstrated that compound 7e activates apoptotic mechanisms and inhibits proliferation in glioblastoma cells.

Psoriasis is an autoimmune disorder. Phosphodiesterase is a family of 1-11 among which PDE4 is most predominant enzymes present in inflammatory cells. Commercially available drugs are synthetic, and these may cause various side effects and are expensive. Dimethyl fumarate is the most frequently used systematic treatment for psoriasis with significant side effects such as myelosuppression, hepatic fibrosis and pulmonary fibrosis. Immune compromise drugs having various side effects, so this project is aimed to propose a novel drug that has more potency, efficiency and least side effects. The docking analysis was carried out to identify the best ligands by predicting the ligand conformation in the active protein sites and ligand binding affinity towards protein. Ligands were docked with the proteins, and all exhibited higher docking score than the standard drug dimethyl fumarate. The TNF- α inhibitors with PDB id such as 2ZJC, 2ZPX and PDE4 Inhibitors with PDB ID such as 3SL3, 1PTW are selected as target proteins, acridone had the best docking score of 19.3502 than standard value 12.997, and with PDB ID 3SL3, acridone showed 26.025 as docking score over the standard value 21.995. it interacted well with the active sites of the proteins. Thus, we infer that these studies will be a leader, in designing new and improved drug target for psoriatic therapy.

Several new amino-substituted acridone and xanthone derivatives have been designed and synthesized, using an efficient methodology from suitable acridone- or xanthone-carboxylic acid intermediates. The antiproliferative activity of the target compounds has been evaluated against four cancer cell lines, namely breast adenocarcinoma MCF-7, acute lymphocytic leukemia CCRF-CEM, and its doxorubicin-resistant variant CEM/ADR5000 and prostate cancer PC-3 cell lines. Selected derivatives have also been tested against the urinary bladder T24 and metastatic melanoma WM266-4 cancer cell lines. Two nitro substituted acridones, bearing a basic side chain as well, were endowed with a remarkable profile against the majority of the cell lines tested, with IC50 values in the low micromolar range. Both compounds cause accumulation at G0/G1 phase, induce apoptosis, and act as potent autophagy inhibitors in PC-3 cells, suggesting their further evaluation in various pathophysiological environments, conditions, and regimens.

The article highlights insights into biological activity using computational methods in products of 1,3,5-triazine-2,4-diamine with 1H-indole-2,3-dione (isatin)/(2E)-13-diphenylprop-2-en-1-one (chalcone)/10H-acridin-9-one (acridone). Biological activity is carried out using the method of electron density, 6-311++G(d,p) for molecular and electronic characteristics. Frontier molecular orbitals provide quantum mechanical descriptors to determine electronic properties. Studies show reduced energy gap with high kinetic stability and the index of electrophilicity is a consequence of delocalized sites of 1,3,5-triazine-2,4-diamine and nucleophilic sites are responsible for biological activity. Enhancement in electrophilicity index of products confirms electron acceptor between the reactants. The structural and molecular docking with different proteins shows that the product molecules are good drugs for the corresponding activity.

Objectives Acridone alkaloids from Citrus and their derivatives show various kinds of biological activity. However, the anticancer activities of dimeric acridone alkaloids with unique structures and the molecular mechanism of these effects are poorly understood. Methods We investigated the cytotoxicity effects of dimeric acridone alkaloids isolated from Marsh grapefruit on human myeloid leukaemia HL-60 cells. Key findings Of the six dimeric acridone alkaloids tested, citbismine-E, the most potent, dose- and time-dependently decreased HL-60 cell viability by inducing apoptosis. The treatment of HL-60 cells with citbismine-E yielded a significant increase in levels of intracellular reactive oxygen species (ROS). Citbismine-E lowered the mitochondrial membrane potential and increased the activities of caspase-9 and -3. In addition, citbismine-E-induced apoptosis, decrease in mitochondrial membrane potential and caspase activation were significantly alleviated by pretreatment of the cells with antioxidant N-acetylcysteine (NAC). Citbismine-E induced intrinsic caspase-dependent apoptosis through ROS-mediated c-Jun N-terminal kinase activation. Citbismine-E-induced production of oxidative stress biomarkers, malondialdehyde and 8-hydroxy-2′-deoxyguanosine was also attenuated by pretreatment with NAC. Conclusions Citbismine-E is a powerful cytotoxic agent against HL-60 cells that acts by inducing mitochondrial dysfunction-mediated apoptosis through ROS-dependent JNK activation. Citbismine-E also induced oxidative stress damage via ROS-mediated lipid peroxidation and DNA damage in HL-60 cells.

Novel N-acylhydrazone derivatives from acridone have been synthesized by condensation of acridone acetohydrazide and various aldehyde. The novel acylhydrazones were tested for their in-vitro antibacterial activity against human pathogenic strains. The MIC results indicate that compound 3f displayed high antibacterial potential against Pseudomonas putida with MIC = 38.46 µg/mL, which is very close to that obtained with the commercial antibiotic. The synthesized compounds were subjected for docking studies to understand the interaction of our compounds and transcriptional regulator enzyme of pseudomonas putida and DNA gyrase complex of Staphyloccocus aureus.

Bioactivity-guided fractionation of the CHCl3-soluble extract of the roots of Paramignya trimera was carried out to obtain a new acridone alkaloid, paratrimerin I. Its structure was elucidated base...

The global impact of malaria remains staggering despite extensive efforts to eradicate the disease. With increasing drug resistance and the absence of a clinically available vaccine, there is an urgent need for novel, affordable, and safe drugs for prevention and treatment of malaria. Previously, we described a novel antimalarial acridone chemotype that is potent against both blood-stage and liver-stage malaria parasites. Here, we describe an optimization process that has produced a second-generation acridone series with significant improvements in efficacy, metabolic stability, pharmacokinetics, and safety profiles. These findings highlight the therapeutic potential of dual-stage targeting acridones as novel drug candidates for further preclinical development.

Development of new drugs with antibacterial potency is an important solution to overcome drug-resistance problems. In the goal to develop novel structure with antibacterial potency, we designed and synthesized novel acridone derivatives bearing triazole nucleus. The novel synthesized compounds were tested for their in vitro antibacterial activity against four bacterial human pathogenic strains. The compound 4h displayed significant antibacterial activities against Staphylcoccus aureus (MRSA) with MIC = 19.6 μg/mL. The synthesized compounds were subjected for docking study to understand the interaction of our compounds and the dihydropteroate synthase (DHPS) in methicillin-resistant Staphylcoccus aureus (MRSA).

An excellent pre-column fluorescent derivatization reagent N-acetylhydrazine acridone for the quantitative determination of malondialdehyde was synthesized. Malondialdehyde was derivatized at 80 °C for 30 min in the presence of trichloroacetic acid. The separation of the derivative was performed on an Agilent ZORBAX SB-C18 column in conjunction with gradient elution. The excitation and emission wavelengths were 370 nm and 420 nm, respectively. The developed method demonstrated good linear relationship in the range of 0.02 pmol to 2.5 pmol (r = 0.9998). The calculated limit of detection and limit of quantification were 2.5 fmol and 8.3 fmol, respectively. The analytical precisions of the method were in the range of 1.36–2.27% (intra-day) and 2.36–3.92% (inter-day) respectively. The method was sensitive, specific and simple. It was successfully implemented to analysis the malondialdehyde in rat prostate.

Background Acridone alkaloids are heterocyclic compounds that exhibit a broad-range of pharmaceutical and chemotherapeutic activities, including anticancer, antiviral, anti-inflammatory, antimalarial, and antimicrobial effects. Certain plant species such as Citrus microcarpa, Ruta graveolens, and Toddaliopsis bremekampii synthesize acridone alkaloids from anthranilate and malonyl-CoA. Results We synthesized two acridones in Escherichia coli. Acridone synthase (ACS) and anthraniloyl-CoA ligase genes were transformed into E. coli, and the synthesis of acridone was examined. To increase the levels of endogenous anthranilate, we tested several constructs expressing proteins involved in the shikimate pathway and selected the best construct. To boost the supply of malonyl-CoA, genes coding for acetyl-coenzyme A carboxylase (ACC) from Photorhabdus luminescens were overexpressed in E. coli. For the synthesis of 1,3-dihydroxy-10-methylacridone, we utilized an N-methyltransferase gene (NMT) to supply N-methylanthranilate and a new N-methylanthraniloyl-CoA ligase. After selecting the best combination of genes, approximately 17.3 mg/L of 1,3-dihydroxy-9(10H)-acridone (DHA) and 26.0 mg/L of 1,3-dihydroxy-10-methylacridone (NMA) were synthesized. Conclusions Two bioactive acridone derivatives were synthesized by expressing type III plant polyketide synthases and other genes in E. coli, which increased the supplement of substrates. This study showed that is possible to synthesize diverse polyketides in E. coli using plant polyketide synthases.

We report the chemistry and biological activities of a Cameroonian Citrus clementina Hort. Ex Tanaka, a vegetatively propagated species. The compounds isolated from this plant were determined to be...

Acridine-based compounds possess anticancer activities by intercalating to DNA. Although they have chemotherapeutic potential, acridine-based compounds are not used to treat cancer. In this study, 2, N10-acridone derivatives are designed and synthesized based on acridone, a ketone derivative of acridine. Herein, acridone is functionalized with alkyl side chains containing terminal nitrogen-based moieties at the N10-position and substituted at the C2-position. The products are evaluated for in vitro cytotoxicity against four cancer cell lines: Molt-3, HepG2, A549, and HuCCA-1. The derivative bearing two butyl piperidine side chains at the C2- and N10-positions is the most active, with IC50 values ranging from 2.96 to 9.46 µM. Molecular modeling studies supported the binding of the derivatives to DNA by intercalation, thereby confirming the observed cytotoxic effects.

Three new compounds comprising two coumarins, paramicoumarins A (1) and B (2), and an acridone alkaloid, paramiacridone (3), together with seven known compounds, were isolated from the n-hexane extract of the roots of Paramignya trimera (Rutaceae). Their structures were elucidated using spectroscopic methods, mainly 1D and 2D NMR. α-Glucosidase inhibition and DPPH radical scavenging activity of the compounds and fifteen other compounds previously isolated from the roots of this plant were evaluated. Most of the compounds exhibited stronger α-glucosidase inhibitory activity than acarbose, the positive control (IC50 = 223.0 μM), and the new compounds paramiacridone (3) and paramicoumarin B (2) showed good inhibitory effect (IC50 = 62.5 and 65.5 μM, respectively). In the DPPH test for radical scavenging activity, the acridone alkaloid glycocitrin III (17) exhibited the highest antioxidant activity (IC50 = 84.2 μM) (compared with the positive control, ascorbic acid, IC50 = 152.7 μM).

A method was developed for the preparation of N-(4-R-4,5-dihydroisoxazol-5-yl)methylacridones by the reaction of aromatic aldehyde oximes with allyl acridones. For the obtained compounds, a high inhibitory activity in relation to test strains of pathogenic microorganisms was revealed, exceeding furacilin.

Three new donor-acceptor (D-A) compounds, positional isomers of phenoxazine-substituted acridone, namely 1-phenoxazine-N-hexylacridone (o-A), 2-phenoxazine-N-hexylacridone (m-A) and 3-phenoxazine-N-hexylacridone (p-A), were synthesized. The synthesized compounds showed interesting, isomerism-dependent electrochemistry. Their oxidation was reversible and their potential (given vs. Fc/Fc+) changed from 0.21 V for o-A to 0.36 V for p-A. In contrast, their reduction was irreversible, isomerism-independent and occurred at rather low potentials (ca. -2.25 to -2.28 V). The electrochemical results led to the following values of the ionization potentials (IPs) and electron affinities (EAs): 5.03 eV and -2.14 eV, 5.15 eV and -2.20 eV, and 5.20 eV and -2.28 eV for o-A, m-A and p-A, respectively. The experimentally obtained values were in very good agreement with those predicted by DFT calculations. All three isomers readily formed single crystals suitable for their structure determination. o-A and p-A crystallized in P1[combining macron] and P21/n space groups, respectively, with one molecule per asymmetric unit, while m-A crystallized in the P21/c space group with two molecules in the asymmetric unit accompanied by disordered solvent molecules. The UV-vis spectra of the studied compounds were isomerism and solvent independent, yielding absorption maxima in the vicinity of 400 nm. Their photoluminescence spectra, in turn, strongly depended on isomerism and the used solvent showing smaller Stokes shifts for the emission bands registered in toluene as compared to the corresponding bands measured in dichloromethane. The photoluminescence quantum yields (φ) were systematically higher for toluene solutions reaching the highest value of 20% for p-A. For all three isomers studied, stationary and time-resolved spectroscopic investigations carried out in toluene at different temperatures revealed spectral features indicating a contribution of thermally activated delayed fluorescence (TADF) to the observed spectroscopic behaviour. The measured photoluminescence quantum yields (φ) were higher for solid state films of pure compounds and for their dispersions in solid matrices (zeonex) than those recorded for toluene and dichloromethane solutions of the studied phenoxazine-N-hexylacridone isomers. The obtained experimental spectroscopic and structural data were confronted with theoretical predictions based on DFT calculations.

A layered aluminophosphate |C14H11NO|2[Al4(HPO4)4F4(H2O)2] (denoted as SYSU-2) with a new topology has been hydrothermally synthesized with N-methyl-9-acridone (NMA) as the organic structure-directing agent. Single-crystal X-ray diffraction analysis reveals that SYSU-2 crystallizes in a triclinic space group P1[combining macron], with the inorganic sheets stacked in an AA sequence. Hydrogen bonds are responsible for the neutral inorganic-organic layer connection. The layer structure of SYSU-2 is constructed by alternating AlO4F2 octahedra and PO4 tetrahedra. The topological analysis of SYSU-2 indicates an independent topology. The NMA layers are self-assembled with π-π interaction. SYSU-2 crystals show interesting dual-band emission fluorescence properties compared with NMA crystals. Under 406 nm UV irradiation, SYSU-2 crystals emit yellow light with two emission bands at 477 and 566 nm, while NMA crystals emit blue light with only one band at 473 nm. The differences may be derived from the difference of stacking orders and distance of NMA molecule layers between the two crystals.

Background: The lack of efficacious therapy for advanced melanoma and neuroblastoma makes new approaches necessary. Therefore, many scientists seek new, more effective, more selective and less toxic anticancer drugs. Objective: We propose the synthesis of the new functionalized analogs of 1-nitroacridine/4- nitroacridone connected to tuftsin/retro-tuftsin derivatives as potential anticancer agents. Methods: Acridine and acridone analogues were prepared by Ullmann condensation and then cyclization reaction. As a result of nucleophilic substitution reaction 1-nitro-9-phenoxyacridine or 1- chloro-4-nitro-9(10H)-acridone with the corresponding peptides, the planned acridine derivatives (10a-c, 12, 17-a-d, 19) have been obtained. The cytotoxic activity of the newly obtained analogs were evaluated against melanotic (Ma) and amelanotic (Ab) melanoma cell lines and neuroblastoma SH-SY5Y by using the XTT method. Apoptosis and cell cycle were analyzed by flow cytometry. Results: Among the investigated analogs compound 12 exhibited the highest potency comparable to dacarbazine action for amelanotic Ab melanoma cells. FLICA test (flurochrome-labeled inhibitors of caspases) showed that this analog significantly increased the content of cells with activated caspases (C+) among both neuroblastoma lines and only Ab melanoma line. Using phosphatidylserine (PS) externalization assay, 12 induced changes in the Ab melanoma plasma membrane structure as the externalization of phosphatidylserine (An+ cells). These changes in neuroblastoma cells were less pronounced. Conclusion: Analog 12 could be proposed as the new potential chemotherapeutic against amelanotic melanoma form especially.

N-substituted acridine-containing 1,2-dioxetanes have been recently proposed as thermochemiluminescence (TCL) universal labels for bioanalytical applications. The TCL properties of these compounds markedly depend on the nature of substituents of the acridine ring. In the attempt to obtain new TCL probes with improved properties and stability, the push-pull approach was adopted, in which both electron withdrawing and electron donating groups are present in the acridine moiety. The results have been useful to better understand the role of the different decorations at the acridine fluorophore in modulating the photophysical properties and the activation parameters of 1,2-dioxetane labels. Moreover, the great versatility and innovation of these molecules make them extremely attractive for bioanalytical applications, in particular as labels for immune- and gene-probe assays.

Exosomes are promising biomarkers for cancer screening, but the development of a robust approach that can sensitively and accurately detect exosomes remains challenging. In the present study, an aptasensor based on the multifunctional signal probe 10-benzyl-2-amino-acridone (BAA) was developed for the colorimetric and photoelectrochemical detection and quantitation of exosomes. Exosomes are captured by cholesterol DNA anchor-modified magnetic beads (MBs) through hydrophobic interactions. This capture process can be monitored under a confocal fluorescence microscope using BAA as the fluorescent signal probe. The aptamer modified copper oxide nanoparticles (CuO NPs) then bind to mucin 1 (MUC1) on the surface of the exosomes to form a sandwich structure (MBs-Exo-CuO NPs). Finally, the MBs-Exo-CuO NPs are dissolved in nitric acid to generate Cu2+, which inhibits the visible-light-induced oxidase mimic activity and photoelectrochemical activity of BAA simultaneously. The changes in absorbance and photocurrent intensities are directly proportional to the concentration of exosomes. In this dual-modal aptasensor, the colorimetric assay can achieve rapid screening and identification, which is especially useful for point-of-care testing. The UV–vis absorbance and photocurrent assays then provide quantitative information, with a limit of detection of 1.09 × 103 particles μL−1 and 1.38 × 103 particles μL−1, respectively. The proposed aptasensor thus performs dual-modal detection and quantitation of exosomes. This aptasensor provides a much-needed toolset for exploring the biological roles of exosomes in specific diseases, particularly in the clinical setting.

Organic room temperature phosphorescent (ORTP) compounds have recently emerged as a promising class of emissive materials with a multitude of potential applications. However, the number of building blocks that give rise to efficient ORTP materials is still limited, and the rules for engineering phosphorescent properties in organic solids are not well understood. Here, we report ORTP in a series of N-substituted acridone derivatives with electron-donating, electron-withdrawing, and sterically bulky substituents. X-ray crystallography shows that the solid-state packing varies progressively between coparallel and antiparallel π-stacking and separated π-dimers, depending on the size of the substituent. The detailed photophysical studies supported by DFT calculations reveal complex dynamics of singlet and triplet excited states, depending on the electronic effects of substituents and solid-state packing. The programmable molecular packing provides a lever to control the triplet-triplet annihilation that is manifested as delayed fluorescence in acridone derivatives with continuous (both parallel and antiparallel) π-stacking.

Nitric oxide (NO) is an important signaling molecule involved in a wide range of physiological and pathological processes. Fluorescent imaging is a useful tool for monitoring NO concentration, which could be essential in various biological and biochemical studies. Here, we report the design of a novel small-molecule fluorescent probe based on 9(10H)acridone moiety for nitric oxide sensing. 7,8-Diamino-4-carboxy-10-methyl-9(10H)acridone reacts with NO in aqueous media in the presence of O2, yielding a corresponding triazole derivative with fivefold increased fluorescence intensity. The probe was shown to be capable of nitric oxide sensing in living Jurkat cells.

Fluorescent amino acids are powerful biophysical tools as they can be used in structural or imaging studies of a given protein without significantly perturbing its native fold or function. Here, we have synthesized and characterized 7-(dimethylamino)acridon-2-ylalanine (Dad), a red-shifted derivative of the genetically-incorporable amino acid, acridon-2-ylalanine. Alkylation increases the quantum yield and fluorescence lifetime of Dad relative to a previously published amino acid, 7-aminoacridon-2-ylalanine (Aad). These properties of Dad make it a potentially valuable protein label, and we have performed initial testing of its ability to be genetically incorporated using an evolved aminoacyl tRNA synthetase., Graphical Abstract

A new coumarin-acridone fluorescent probe S was designed and synthesized, and the structure was confirmed with 1H/13C NMR spectrometry, single-crystal X-ray diffraction, and high-resolution mass spectrometry. This probe has high sensitivity and selectivity for Fe3+ over other testing metal ions at 420 or 436 nm in acetonitrile–MOPS (3-Morpholinopropanesulfonic Acid) buffer solution (20.0 μM, pH = 6.9, 8:2 (v/v)). Under physiological conditions, the probe displayed satisfying time stability with a detection limit of 1.77 µM. In addition, probe S was successfully used to detect intracellular iron changes through a fluorescence-off mode, and the imaging results of cells and zebrafish confirmed their low cytotoxicity and satisfactory cell membrane permeability, as well as their potential biological applications.

Evaluating the binding interaction between biomacromolecules and various chemical compounds is one of the most biologically researched topics. The present experimental study attempted to investigate the binding interaction between two types of acridone derivative, namely 8-chloro acridone (CA) and nitrile cyanide acridone (NCA) as antineoplastic agents and calf thymus DNA (ctDNA) by applying various spectroscopic techniques. The binding interactions were first characterized by fluorescence quenching experiments, and it was demonstrated that NCA had higher affinity to ctDNA and bound to it more tightly. Further analysis indicated that the quenching process between CA and ctDNA was controlled by a dynamic mechanism, while the dominant process in ctDNA–NCA interaction was static. Analysis of thermodynamic parameters showed that hydrophobic forces played a key role in the interaction between ctDNA and CA, whereas ctDNA–NCA complex was mainly stabilized by van der Waals interactions. In terms of the latter interaction, external binding also contributed to the stabilization of the formed complex. On the basis of RLS results, we concluded that CA had stronger potential toxicity on ctDNA than NCA. Fluorescence competition studies aimed at uncovering the mode of binding and indicated that CA and NCA probably intercalated into ctDNA. Thermal denaturation studies confirmed the displacement experiments and showed that CA brought about a stronger effect on the ctDNA stabilization. Data gathered by spectroscopy studies were further supported by viscosity experiments. These studies also showed that CA and NCA intercalated into ctDNA by a non-classical and classical mode, respectively. The results of circular dichroism experiments revealed no considerable conformational transition occurred in ctDNA upon the binding interactions and ctDNA remained in B-form. Based on the spectroscopic results and the binding affinity of CA to double-strand and single-strand ctDNA, we inferred that although CA predominantly intercalated into ctDNA, a small population of its molecules might bind to the grooves of ctDNA. In case of NCA, all the experimental results confirmed that NCA molecules intercalated into ctDNA by a classical mode.

A comprehensive spectroscopic, photophysical and electrochemical investigation of N-alkylacridones, their newly synthesised chlorosulfonyl and water-soluble sulfonic acid derivatives has been undertaken in solution at room temperature. The study includes absorption and emission spectra together with quantitative measurements of the deactivation of the first excited singlet state, from which the rate constants for all the decay processes has been obtained. A comparison on the gradual change of the electronic spectral and photophysical properties with the degree of substitution is considered. In addition the electrochemical behavior of the water-soluble acridones at different pH values was obtained by cyclic and differential pulse voltammetry. The oxidation mechanism of disulfonated acridone is found to occur in one consecutive and irreversible charge transfer pH-dependent reaction. The water-soluble acridones were found to display long lifetime values, dependent on the pH and solvent polarity. This opens a door for its use as selective probes for different cellular environment and targets.

In this article topical issues in treatment of acute respiratory infections in children and place of both exogenous interferons and interferon inducer drugs in their treatment are reviewed, including mechanisms of action, advantages and disadvantages of their application, special features of use in children. The latest clinical and laboratory data on the efficacy meglumine acridone acetate use in this pathology are given here. Depletion of inflammatory manifestations, correction of immune system imbalance were observed, leading to reduction of symptoms severity and disease duration, which, along with the good tolerability of the drug allows us to recommend it for widespread use in children.

The article justifies the use of interferon inducers in a clinical practice of pediatrician. The authors isolated a group of derivatives of acridone acetic acid, which effectiveness is associated with the features of pharmacokinetics and pharmacological activity. They demonstrated preventive and therapeutic efficacy of cycloferon in the complex treatment of children with influenza and other acute respiratory viral infections, herpes virus, arbovirus, rotavirus infections, viral hepatitis and tick-borne encephalitis due to its immunomodulatory potency. The article analyzed the use of cycloferon in frequently sick children, patients with allergic diseases, chronic tonsillitis, etc.; also it showed a decrease in the frequency of relapses of both infectious and allergic diseases, the possibility of combined use with other etiotropic and symptomatic drugs.

A class of π-extended BF2 β-diketone chromophores, ADBF2-a and ADBF2-b, that containing electron donating N-butyl acridone units have been synthesized. ADBF2-a and ADBF2-b are highly fluorescent with quantum efficiencies (ΦF) close to unity in toluene. The fluorescence of ADBF2-b displays more pronounced solvatochromism and shows a twisted intramolecular charge transfer (TICT) character in polar solvent and aggregation induced emission enhancement (AIEE) behavior. Furthermore, ADBF2-b shows high contrast and sensitive acid/base induced emission “On/Off” switching that result from the reversible protonation/deprotonation of the nitrogen atom. The compounds are also highly luminescent in solid state with a ΦF value of 0.63 for ADBF2-a and 0.28 for ADBF2-b. Single crystal analysis reveals the highly rigid and planar backbone of ADBF2-a. The emission stimuli-responsive properties of the compounds in solid state have been investigated. ADBF2-a shows yellow emission (λem = 564 nm) in crystalline state while turned to be orange (λem = 586 nm) after grinding. Intriguingly, CH2Cl2 vapor fuming of the ground solid led to red emissive (λem = 624 nm) solid, which turned to original yellow color with further CH2Cl2 vapor fuming. The solid of ADBF2-b emits red (λem = 645 nm) fluorescence in crystalline state and red-shifted to λem = 680 nm for amorphous solid after mechanical grinding. The crystalline state was recovered by CH2Cl2 vapor fuming. We believe that this BF2 system will inspire the development of high luminescent solid-state materials, and provide important insights into smart stimuli-responsive properties.