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Sorafenib was the only small-molecule drug approved by FDA for treatment of the advanced hepatocellular carcinoma (HCC). Recent study indicated that YM155 was a promising agent for HCC cells with high survivin expression, however, the antitumor activity needs to be further improved. Based on molecular docking and rational design method, a series of multi-substituted benzyl acridone derivatives were designed and synthesized. MTT assay indicated that some of the synthesized compounds displayed better antiproliferative activity against HepG2 cells than YM155. Later study indicated that the representive compound 8u may directly interact with survivin protein and induce HepG2 cells apoptosis, which is different from YM155. In addition, ADME property was predicted in silico, and it performed well. Moreover, in vivo preliminary experiments showed that 8u may be a good lead compound in the treatment of HCC.

Hybrid systems of acridones with substituted pyrimidines were designed with an objective of discovering next generation anticancer agents targeting multiple mechanisms in the cancer cell. Hybrid compounds were synthesized by simple and convenient methods in the lab, characterized by NMR and Mass spectral methods and screened for cytotoxicity against A549 (lung), Hela (cervical), MCF7 (breast) and MDA-MB-231 (breast) cancer cell lines respectively. Evaluation of compounds for cell proliferation identified active compounds 11b, 11d and 11h against MCF7, MDA-MB-231 and A549 cell lines. Further absorption titrations with CT-DNA and gel electrophoresis identified that hybrid molecules displayed anticancer activity partly by DNA intercalation. Also further results of western blotting assay with Akt kinase identified that hybrid compounds have the ability to inhibit the Akt kinase activity and induce apoptosis, with ABCC1 suggests that active compounds too have the ability to modulate multidrug resistance (MDR) associated with ABCC1/MRP1. Selective Akt1 kinase assay have identified 11a, 11b, 11d and 11h as potential inhibitors. Molecular docking studies identified the orientation and binding interactions at the active site of Akt1 and DNA. Compounds 12e and 12f have shown good cytotoxicity profile against lung cancer cell lines of sensitive and resistant type. Acute toxicity study of compound 12f at the dose of 5000 mg/kg has identified no signs of clinical toxicity. Prediction of ADMET properties and oral toxicity of the drug likeness features of new hybrid systems were carried out using software's. This experimental data suggests that hybrid systems of acridone with substituted pyrimidines can be taken as a lead for the design of efficient inhibitors and active compounds which can be taken up for further studies.

Drug resistance in cancer is an unmet medical challenge and a major drawback for the failure of many chemotherapeutic drugs. Search for targeted, effective drug with minimum toxicity is an urgent need. Acridone which is an alkaloid derivative has been attributed as molecule in reversing drug resistance in cancer cells for a long time now. In the present investigation, an attempt has been made to explore the chemosensitizing ability of 2,4-dimethylacridones with alkyl side chain containing terminally substituted tertiary amino groups. Considering the structural features required for the MDR reversal activity, acridone derivatives have been synthesized with propyl and butyl side chain containing morpholinyl, piperidinyl, N-methylpiperazinyl, N,N-diethylamino, N-diethanolamino, N-[(β-hydroxylethyl)]piperazino at the terminus of the alkyl side chain. cLogP values for the synthesized compounds ranged from 2.96 to 4.72 for the propyl derivatives and 3.41 to 5.15 for the butyl derivatives. All the compounds were screened against breast cancer sensitive MCF7 and resistant MCF7/ADR cell lines. Compounds 12e and 12f have shown better cytotoxicity profiles with IC50 of 4 ± 0.05 and 2 ± 0.03 μM against MCF7 cells, 5.21 ± 0.13 and 2.56 ± 0.05 μM against MCF7/ADR cells. Photolabelling studies with [3H]-azidopine and molecular docking studies have identified that 2,4-dimethylacridones have potential to modulate the P-gp mediated multidrug resistance. Docking studies identified that compounds have shown favorable interactions with P-gp. QSAR equation was derived for cytotoxicity vs molecular descriptors of acridone derivatives. Best models with good predictive ability have been generated with very high square correlation coefficient (R2) values of 0.889, 0.964 and 0.983.

Hybrid pharmacophore anti-proliferative compounds, comprised of mycophenolic acid (MPA) and 1-nitroacridine/4-nitroacridone derivative have been synthesized and evaluated as inhibitors of five different leukemia cell lines (Jurkat, Molt-4, HL-60, CCRF-CEM, L1210) and human peripheral blood mononuclear cells from healthy donors. These conjugates possess different length of the linker between MPA and heterocyclic units. The type of heterocyclic part influenced their cytotoxic and anti-proliferative properties. Coupling of MPA 1 with 9-(ω-aminoalkyl)amino-1-nitroacridines 2 and 1-[(ω-aminoalkyl)-4-nitro-9(10 H )]-acridones 3 was tested. Although all tested conjugates were active, compounds 4a – e exhibited the highest potency. Preliminary experiments with GMP suggested that the tested compounds acted as IMPDH inhibitors.

A series of 10-substituted hydroxy-10 H -acridin-9-ones were synthesized and studied as potential antipsoriatic agents. The antiproliferative activity of the novel derivatives, which can be considered as aza-analogues of the antipsoriatic drug anthralin, was determined using the human keratinocyte cell line HaCaT. Structure–activity relationships with respect to the nature of the N-substituent at the acridone scaffold were delineated. Release of lactate dehydrogenase (LDH) was used to exclude non-specific cytotoxic effects. As compared to anthralin, N-substitution of the acridone scaffold in the target compounds provided agents devoid of radical producing properties, which was documented by their ineffectiveness to interact with the free radical 2,2-diphenyl-1-picrylhydrazyl. This was in excellent agreement with the data obtained from the LDH assay in which the novel compounds did not induce membrane damage. Benzyl substitution at the 10-position yielded keratinocyte growth inhibitory activity in the low micromolar range. The most potent inhibitor of keratinocyte hyperproliferation was compound 8a having an N-methyl group and a 1,3-dihydroxy arrangement at the acridone scaffold, with an IC 50 value comparable to that of anthralin.

In order to explore the structure–activity relationships in the acronycine and psorospermin series, simplified analogues of the highly cytotoxic (±)-(2 R *,1′ R *)-5-methoxy-11-methyl-2-(2-methyloxiran-2-yl)-1,2-dihydro-11 H -furo[2,3- c ]acridin-6-one and (±)-(2 R *,1′ R *)-5-methoxy-13-methyl-2-(2-methyloxiran-2-yl)-1,2-dihydro-13 H -benzo[ b ]furo[3,2- h ]-acridin-6-one lacking the fused furan ring, including 3-allyloxy-1-methoxy-10-methyl-acridin-9(10 H )-one, 3-allyloxy-1-methoxy-5-methyl-benzo[ b ]acridin-12(5 H )-one, the corresponding epoxides, and related dihydrodiol esters and diesters were prepared. Only the simplified oxirane compounds displayed significant antiproliferative activity compared to the parent compounds. The oxirane alkylating unit appears indispensible to observe significant antiproliferative activity in both series, but the presence of the angularly fused furan ring does not appear as a crucial structural requirement to observe significant cytotoxic activity.

In order to explore the structure–activity relationships in the acronycine series, simplified analogues of cis -1,2-diacetoxy-1,2-dihydroacronycine and cis -1,2-diacetoxy-1,2-dihydrobenzo[ b ]acronycine (S23906-1, under clinical trials) lacking the fused pyran ring, but possessing an acetoxymethyl leaving group at position 4 were prepared. These new analogues only displayed marginal antiproliferative activity compared to the parent compounds. The presence of the angularly fused dimethylpyran ring appears as an indispensable structural requirement to observe significant cytotoxic activity in this series.

A number of acridone-based oxadiazoles 11a-n have been synthesized and evaluated for their anticonvulsant activity against pentylenetetrazole (PTZ)- and maximal electroshock (MES)-induced seizures in mice. Also, their neurotoxicity was evaluated by the rotarod test. Most of the compounds exhibited better anticonvulsant activity and higher safety respect to the standard drug, phenobarbital. Among the tested derivatives, compounds 11l with ED50 value of 2.08 mg/kg was the most potent compound in the PTZ test. The anticonvulsant effect of compound 11l was blocked by flumazenil, suggesting the involvement of benzodiazepine (BZD) receptors in the anticonvulsant activity of prototype compound 11l. Also, docking study of compound 11l in the BZD-binding site of GABAA receptor confirms possible binding of compound 11l with BZD receptors.

Some novel aminosubstituted azapyranoxanthenones, bearing structural similarity to the acridone alkaloid acronycine, have been designed and synthesized. Their in vitro cytotoxicities against the murine L1210 leukemia and the human solid tumor HT-29 cell lines have been investigated. Their eventual selective effect on a phase of the cell cycle was evaluated, using HT-29 cells. A number of the new derivatives exhibited interesting cytotoxic activity against the human solid tumor cell line.

A hypothesis of bioactivation of the antitumor alkaloid acronycine by transformation of the 1,2-double bond into the corresponding epoxide in vivo and the suggestion that acronycine could interact with DNA, led to develop 1,2-dihydroxy-1,2-dihydrobenzo[b]acronycine diesters (1,2-dihydroxy-6-methoxy-3,3,14-trimethyl-1,2,3,14-tetrahydro-7H-benzo[b]pyrano[3,2-h]acridin-7-one diesters) as new anticancer drug candidates. Compared to acronycine these compounds were markedly more potent, both in terms of cytotoxicity and antitumor activity. The biological activity of these compounds was strongly related with their ability to give covalent adducts with purified as well as genomic DNA. Formation of those adducts involves alkylation of the exocyclic N-2 amino groups of guanines exposed in the minor groove of double helical DNA by the carbocation produced by the elimination of the acyloxy leaving group at position 1 of the drug. A transesterification process of the ester group from position 2 to position 1 accounted for the intense activity of cis-1-hydroxy-2-acyloxy-1,2-dihydrobenzo[b]acronycine derivatives. Cis-1,2-diacetoxy-1,2-dihydrobenzo[b]acronycine, which displays a particularly impressive broad antitumor spectrum, is currently developed by Servier Laboratories under the code S23906-1.

A novel series of acridone linked to 1,2,3-triazole derivatives have been synthesized and evaluated in vitro for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. The synthetic approach was started from the reaction of 2-bromobenzoic acid with aniline derivatives and subsequent cyclization reaction to give acridone derivatives. Then, reaction of the later compounds with propargyl bromide followed by azide-alkyne cycloaddition reaction (click reaction) led to the formation of the title compounds in good yields. Among the synthesized compounds, 10-((1-(4-chlorobenzyl)-1H-1,2,3-triazol-4-yl)methyl)-2-methoxyacridin-9(10H)-one 9g, depicted the most potent anti-AChE activity (IC50 = 7.31 μM). Also, docking study confirmed the results obtained through in vitro experiments and predicted possible binding conformation.

A series of novel pyridyl acridone derivatives comprised of a pseudo-five-cyclic system to extend the π-conjugated acridone chromophore, were designed and synthesized as potent DNA binding antitumor compounds. Most synthesized compounds displayed good activity against human leukemia K562 cells in MTT tests, with compound 6d exhibiting the highest activity with IC 50 value at 0.46 μM. Moreover, 6d showed potent activities against solid tumor cell lines (0.16–3.79 μM). Several experimental studies demonstrated that the antitumor mode of action of compound 6d involves DNA intercalation, topoisomerase I inhibition, and apoptosis induction through the mitochondrial pathway. In summary, compound 6d represents a novel and promising lead structure for the development of new potent anticancer DNA-binding agents.

The present study describes the synthesis of fifteen 2-(9-oxoacridin-10(9H)-yl)-N-phenyl acetamide derivatives (13a–o) through condensation of 2-chloro-N-phenyl acetamides (12a–o) with acridone molecule (10). All the synthesized compounds were screened for their anti-cancer activity against three diverse cell lines including breast (MCF-7), cervical (HeLa) and lung adenocarcinoma (A-549) employing standard MTT assay. Among synthesized molecules, 13k and 13l showed good cytotoxicity activity against considered three cancer cell lines. Additionally, in silico studies of multidrug resistance modulator (MDR) effects of these compounds was performed by docking simulation in the ATP binding site of P-gp. The results of docking simulation displayed important interactions of these molecules in the active site of this protein and predicted their MDR modulator behavior.

In the context of the design and synthesis of minor groove binding and intercalating DNA ligands some new oligopyrrole carboxamides were synthesized. These hybrid molecules (combilexins) possess a variable and conformatively flexible spacer at the N-terminal end. As intercalating tricyclic systems acridone, acridine, anthraquinones and in a special case iminostilbene terminate the N-terminal end of the pyrrole chain. The cytotoxicity was examined by the NCI antitumor screening, furthermore, biophysical as well as biochemical studies were performed in order to get some information about the DNA binding properties and topoisomerase inhibition effect of this new series of molecules.

Multidrug resistance (MDR) is one of the main obstacles limiting the efficacy of chemotherapy treatment of tumors. Parent acridones 1A and 1B were prepared by the Ullmann reaction followed by cyclization and N-alkylation. N-(omega-Chloroalkyl) analogues were subjected to iodide catalyzed nucleophilic Substitution reaction with secondary amines to get the compounds 3A-13A and 3B-13B, which enhanced the uptake of vinblastine in KBCh(R)-8-5 cells to a greater extent (2.6-13.1-fold relative to control) than verapamil. The study oil the structure-activity relationship revealed that substitution of -H at position C-4 in acridone nucleus by -OCH3 increased the cytotoxic and anti-MDR activities. The ability of acridones to inhibit calmodulin dependent cyclic AMP phosphodiesterase has been determined and the results have shown a strong positive correlation between anti-calmodulin activity and cytotoxicity in KBCh(R)-8-5 cells or anti-MDR activity. (C) 2003 Elsevier SAS. All rights reserved.