Identification of 1,3-diiminoisoindoline carbohydrazides as potential antimalarial candidates

A series of inhibitors of plant enzymes of the non-mevalonate pathway from herbicide research efforts at BASF were screened for antimalarial activity in a cell-based assay. A 1,3-diiminoisoindoline carbohydrazide was found to inhibit the growth of Plasmodium falciparum with an IC(50) value <100 nM. Synthesis of a variety of derivatives allowed an improvement of the initial antimalarial activity down to IC(50) =18 nM for the most potent compound, the establishment of a structure-activity relationship, and the evaluation of the cytotoxic profile of the diiminoisoindolines. Furthermore, interesting configurational and conformational aspects for this class of compounds were studied by computational and X-ray crystal structure analysis. Some of the compounds can act as tridentate ligands, forming 2:1 ligand-iron(III) complexes, which also display antimalarial activity in the nanomolar IC(50) range, paired with low cytotoxicity.     

Synthesis of aromatase inhibitors and dual aromatase steroid sulfatase inhibitors by linking an arylsulfamate motif to 4-(4H-1,2,4-triazol-4-ylamino)benzonitrile: SAR, crystal structures, in vitro and in vivo activities

4-(((4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino)methyl)phenyl sulfamate (6 a) was the first dual aromatase-sulfatase inhibitor (DASI) reported. Several series of its derivatives with various linker systems between the steroid sulfatase (STS) and the aromatase inhibitory pharmacophores were synthesised and evaluated in JEG-3 cells. The X-ray crystal structures of the aromatase inhibitors, DASI precursors 42 d and 60, and DASI 43 h were determined. Nearly all derivatives show improved in vitro aromatase inhibition over 6 a but decreased STS inhibition. The best aromatase inhibitor is 42 e (IC(50)=0.26 nM) and the best DASI is 43 e (IC(50 aromatase)=0.45 nM, IC(50 STS)=1200 nM). SAR for aromatase inhibition shows that compounds containing an alkylene- and thioether-based linker system are more potent than those that are ether-, sulfone-, or sulfonamide-based, and that the length of the linker has a limited effect on aromatase inhibition beyond two methylene units. Compounds 43 d-f were studied in vivo (10 mg kg(-1), single, p.o.). The most potent DASI is 43 e, which inhibited PMSG-induced plasma estradiol levels by 92 % and liver STS activity by 98 % 3 h after dosing. These results further strengthen the concept of designing and developing DASIs for potential treatment of hormone-related cancers.     

1,3-二苯基-3-（苯胺基）-1-丙酮衍生物对α-葡萄糖苷酶抑制活性的研究

利用Mannich反应合成了24个1,3-二苯基-3-（苯胺基）-1-丙酮衍生物（其中8个为新化合物）,通过测定该系列化合物对α-葡萄糖苷酶活性半抑制浓度来评定其抑制活性,探索化合物分子中苯环上取代基对α-葡萄糖苷酶催化活性的影响。结果表明：新化合物24对α-葡萄糖苷酶的抑制活性稍好,IC50值为57.9μmol.L-1,其余大部分化合物对α-葡萄糖苷酶的IC50值大于100μmol.L-1,说明新化合物24苯环上取代基种类、数目和位置对α-葡萄糖苷酶抑制活性有明显的影响。动力学分析表明该系列化合物为α-葡萄糖苷酶的非竞争性抑制剂。     

Synthesis, in vitro cytotoxicity, and interaction with DNA of platinum(II) complexes with N-monocycloalkyl derivatives of 1R,2R-diaminocyclohexane as carrier ligands

A series of platinum(II) complexes with N-monocyclopentyl/cyclohexyl derivatives of 1R,2R-diaminocyclohexane as carrier ligands and dicarboxylate anions as leaving groups were synthesized and characterized. All complexes were characterized by elemental analysis, IR, (1)H NMR, and (13)C NMR spectroscopy, as well as ESIMS. The in vitro antiproliferative activities were tested by MTT assay against four human cancer cell lines; breast carcinoma (MCF-7) and colon cancer (HCT-116) cells were particularly sensitive, especially to complexes 1f (IC(50) =9.81 and 1.49 μM) and 2f (IC(50) =4.59 and 0.36 μM). Flow cytometry indicated that representative compounds exert cytotoxicity toward MCF-7 and HCT-116 cells through induction of apoptosis and blockage of cell-cycle progression in the S phase, similar to cisplatin. The interaction between the platinum(II) complexes and pET22b plasmid DNA was observed by agarose gel electrophoresis, revealing that complex 2f has the capacity to distort plasmid DNA in a manner distinct from that of oxaliplatin.     

Focused libraries of 16-substituted estrone derivatives and modified e-ring steroids: inhibitors of 17beta-hydroxysteroid dehydrogenase type 1

17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1), an oxidoreductase which has a preferential reductive activity using NADPH as cofactor, converts estrone to estradiol and is expressed in many steroidogenic tissues including breast and in malignant breast cells. As estradiol stimulates the growth and development of hormone-dependent breast cancer, inhibition of the final step of its synthesis is an attractive target for the treatment of this disease. The parallel synthesis of novel focused libraries of 16-substituted estrone derivatives and modified E-ring pyrazole steroids as new potent 17beta-HSD1 inhibitors is described. Substituted 3-O-sulfamoylated estrone derivatives were used as templates and were immobilised on 2-chlorotrityl chloride resin to give resin-bound scaffolds with a multi-detachable linker. Novel focused libraries of 16-substituted estrone derivatives and new modified E-ring steroids were assembled from these immobilised templates using solid-phase organic synthesis and solution-phase methodologies. Among the derivatives synthesised, the most potent 17beta-HSD1 inhibitors were 25 and 26 with IC50 values in T-47D human breast cancer cells of 27 and 165 nm, respectively. Parallel synthesis resulting in a library of C5'-linked amides from the pyrazole E-ring led to the identification of 62 with an IC50 value of 700 nM. These potent inhibitors of 17beta-HSD1 have a 2-ethyl substituent which will decrease their estrogenic potential. Several novel 17beta-HSD1 inhibitors emerged from these libraries and these provide direction for further template exploration in this area. A new efficient diastereoselective synthesis of 25 has also been developed to facilitate supply for in vivo evaluation, and an X-ray crystal structure of this inhibitor is presented.     

Synthesis and Structure–Activity Relationship Studies of Derivatives of the Dual Aromatase–Sulfatase Inhibitor 4‐{[(4‐Cyanophenyl)(4H‐1,2,4‐triazol‐4‐yl)amino]methyl}phenyl sulfamate

4‐{[(4‐Cyanophenyl)(4H‐1,2,4‐triazol‐4‐yl)amino]methyl}phenyl sulfamate and its ortho‐halogenated (F, Cl, Br) derivatives are first‐generation dual aromatase and sulfatase inhibitors (DASIs). Structure–activity relationship studies were performed on these compounds, and various modifications were made to their structures involving relocation of the halogen atom, introduction of more halogen atoms, replacement of the halogen with another group, replacement of the methylene linker with a difluoromethylene linker, replacement of the para‐cyanophenyl ring with other ring structures, and replacement of the triazolyl group with an imidazolyl group. The most potent in vitro DASI discovered is an imidazole derivative with IC₅₀ values against aromatase and steroid sulfatase in a JEG‐3 cell preparation of 0.2 and 2.5 nM , respectively. The parent phenol of this compound inhibits aromatase with an IC₅₀ value of 0.028 nM in the same assay.     

Synthesis, structure analysis, and antitumor evaluation of 3,6-dimethyl-1,2,4,5-tetrazine-1,4-dicarboxamide derivatives

3,6-Dimethyl-1,2,4,5-tetrazine-1,4-dicarboxamide derivatives were synthesized, and their structures were confirmed by single-crystal X-ray diffraction. This reaction yields the 1,4-dicarboxamide derivatives rather than the 1,2-dicarboxamide derivatives. Their in vitro antitumor activities were evaluated against SGC-7901, HO-8910, MCF-7, and A-549 cells. The results showed several compounds to be endowed with cytotoxicity in the low micromolar range. One compound (IC(50) =0.57 μM) was further evaluated in vivo against an A-549 xenograft in BALB/cA nude mice; it effected 76.4% inhibition of tumor weight through intraperitoneal (i.p.) administration of 40 mgkg(-1) body weight. Moreover, its acute toxicity was evaluated, and the i.p. LD(50) value was 325 mgkg(-1) in mice.     

Novel 4-amino bis-pyridinium and bis-quinolinium derivatives as choline kinase inhibitors with antiproliferative activity against the human breast cancer SKBR-3 cell line

Choline kinase (ChoK) is the first enzyme in the CDP-choline pathway that synthesizes phosphatidylcholine, the major phospholipid in eukaryotic cell membranes. Human ChoK has three isoforms: ChoKα1, α2, and β. Specific inhibition of ChoKα has been reported to selectively kill tumor cells. In this study, ten new symmetrical bis-pyridinium and bis-quinolinium derivatives were synthesized and tested for their ability to inhibit human ChoKα2. These compounds have electron-releasing groups at position 4 of the pyridinium or quinolinium rings. 1,1'-[(Butane-1,3-diylbis(benzene-1,4-diylmethylene)]bis[4-(4-bromo-N-methylanilino)pyridinium)] dibromide and 1,1'-(biphenyl-3,3'-diylmethylene)bis[7-chloro-4-(perhydroazepine-1-yl)quinolinium] dibromide were identified as highly potent ChoK inhibitors with IC(50) values of 80 nM. Kinetic enzymatic assays indicated a mixed and predominantly competitive mechanism of inhibition for these compounds, which exhibited strong antiproliferative activity (EC(50) 1 μM) against the human breast cancer SKBR3 cell line.     

Non-steroidal aromatase inhibitors based on a biphenyl scaffold: synthesis, in vitro SAR, and molecular modelling

The synthesis and in vitro biological evaluation (JEG-3 cells) of a series of novel and potent aromatase inhibitors, prepared by microwave-enhanced Suzuki cross-coupling methodology, are reported. These compounds possess a biphenyl template incorporated with the haem-ligating triazolylmethyl moiety, either on its own or in combination with other substituent(s) at various positions on the phenyl rings. The most potent aromatase inhibitor reported herein has an IC(50) value of 0.12 nM, although seven of its congeners are also highly potent (IC(50)相似文献   

New peptolides from the cyanobacterium Nostoc insulare as selective and potent inhibitors of human leukocyte elastase

Eight new cyanopeptolins (insulapeptolides A-H) were obtained from the cyanobacterium Nostoc insulare. Their isolation was guided by their bioactivity toward the target enzyme human leukocyte elastase, molecular biological investigations, and MALDI-TOF analysis. These peptides are selective inhibitors of human leukocyte elastase with activities in the nanomolar range. Insulapeptolide D was the most potent compound with an IC(50) value of 85 nM (K(i) value of 36 nM).     

Synthesis, biological evaluation, and molecular modeling studies of rebeccamycin analogues modified in the carbohydrate moiety

A new series of indolocarbazole glycosides containing disaccharides were synthesized and their in vitro antiproliferative activity was evaluated against three human cancer cell lines (A2780, H460, and GLC4). Cytotoxicity appeared to be remarkably affected by the regio- and stereochemical features of the disaccharide moiety. In vivo antitumor activity of the compounds studied, two of which having IC(50)<100 nm, was determined using ovarian cancer cell line A2780 xenografted on nude mice. One compound showed an efficacy similar to that of the reference compound edotecarin, though with a lower long-lasting activity. The topoisomerase I inhibitory properties of some compounds were also examined. Molecular dynamics simulations of the ternary topoisomerase I-DNA-ligand complexes were performed to analyze the structural features of topoisomerase I poisoning with this class of indolocarbazoles. A plausible explanation of their biological behavior was provided. These theoretical results were compared with the recently published crystal structure of an indolocarbazole monosaccharide bound to the covalent human topoisomerase I-DNA complex.     

Novel rhein analogues as potential anticancer agents

Two series of rhein analogues were synthesized with modification at the 3-position. Their cytotoxicities were evaluated using an MTT assay. Among all the compounds synthesized, one compound showed the best potency, with an IC(50) value of 2.7 μM against the HeLa cell line and 0.6 μM against the MOLT4 cell line.     

Coumarin-Tagged Dinuclear Trithiolato-Bridged Ruthenium(II)⋅Arene Complexes: Photophysical Properties and Antiparasitic Activity

The synthesis, characterization, photophysical and biological properties of 13 new conjugate coumarin-diruthenium(II)⋅arene complexes against Toxoplasma gondii are presented. For all conjugate organometallic unit/coumarins, an almost complete loss of fluorescence efficacy was observed. However, the nature of the fluorophore, the type of bonding, the presence and length of a linker between the coumarin dye and the ruthenium(II) moiety, and the number of dye units influenced their biological properties. The in vitro activity against a transgenic T. gondii strain grown in human foreskin fibroblasts (HFF) leads to IC₅₀ values for T. gondii β-gal from 105 to 735 nM. Of note is that nine compounds displayed lower IC₅₀ than the standard drug pyrimethamine. One compound applied at its IC₅₀ did not affect B-cell proliferation but had an impact on T-cell proliferation in murine splenocyte cultures. Transmission electron microscopy of T. gondii β-gal-infected HFF showed that treatment predominantly affected the parasites’ mitochondrion.     

A Series of Thiadiazolyl-Benzenesulfonamides Incorporating an Aromatic Tail as Isoform-Selective,Potent Carbonic Anhydrase II/XII Inhibitors

We describe the synthesis of a series of thiadiazolyl-benzenesulfonamide derivatives carrying an aromatic tail linked by an amide linker ( 12–34 ), as human carbonic anhydrase (hCA) inhibitors. These thiadiazol derivatives were evaluated against four physiologically relevant CA isoforms (hCA I, II, IX, and XII), and demonstrated intriguing inhibitory activity against CA II with K_i values in the range of 2.4–31.6 nM. Besides hCA II, also hCA XII activity was potently inhibited by some of the derivatives (K_i=1.5–88.5 nM), producing dual inhibitors of both isoforms. Notably, compound 17 was the most potent dual CA II (K_i=3.1 nM) and XII (K_i=1.5 nM) inhibitor with a significant selectivity ratio over CA I and IX isoforms. In conclusion, although all compounds exhibited preferential activity towards hCA II, the nature of the substituents at the tail part of the main scaffold influenced the activity and selectivity toward other isoforms.     

Synthesis and biological evaluation of pyrazolylnaphthoquinones as new potential antiprotozoal and cytotoxic agents

The importance of American trypanosomiasis (Chagas' disease) in human pathology is widely known. The prognosis of this disease is poor and the choice of effective medicines limited, thus study of new drugs is absolutely necessary. In this work, the activities of three new pyrazolylnaphthoquinones, heterocyclic naphthoquinones bearing 3-aminopyrazole rings, were evaluated on Trypanosoma cruzi, the etiological agent of Chagas' disease. These activities were compared with those of three 5-aminoisoxazole analogues. In addition, since these compounds belong to a family of antiprotozoal and cytotoxic/antitumor agents, the activities of all six against Plasmodium falciparum, Trypanosoma brucei rhodesiense, and murine L-6 cells were also investigated. In the biological tests, five of the compounds showed significant in vitro trypanocidal activities against T. cruzi, with activities similar to that of benznidazole. Two of the 5-aminoisoxazole analogues also showed good activities, in one case highly selective, against the K1 and NF54 strains of P. falciparum (IC(50)<0.12 microg mL(-1)). Three of the compounds were cytotoxic to murine L-6 cells (IC(50)=0.21-0.50 microg mL(-1)). The results suggested that the three pyrazolylnaphthoquinones and one of the 5-aminoisoxazole analogues could be starting points for lead optimization programs against T. cruzi and P. falciparum, respectively.     

Carbonic anhydrase inhibitors: design of membrane-impermeant copper(II) complexes of DTPA-, DOTA-, and TETA-tailed sulfonamides targeting the tumor-associated transmembrane isoform IX

The synthesis and carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of two series of aromatic sulfonamides and their Cu(II) derivatives, incorporating metal-complexing moieties of the DTPA, DOTA, and TETA type are reported. The new compounds were designed in such a way as to possess high affinity for Cu(II) ions, exploiting four pendant carboxylate moieties in the DTPA derivatives, as well as the cyclen/cyclam macrocyles, and three pendant acetate moieties in the DOTA and TETA derivatives. The new derivatives showed modest inhibition of the cytosolic isoform CA I (K(I) values in the range of 66-2130 nM), were better CA II inhibitors (K(I) values in the range of 21-360 nM), and excellent inhibitors of the tumor-associated isoform CA IX (K(I) values in the range of 4.1-110 nM), with selectivity ratios for the inhibition of the tumor (CA IX) over the cytosolic (CA II) isozyme in the range of 10.74-20.88 for the best derivatives. Copper complexes were more inhibitory than the corresponding ligand sulfonamides, and showed membrane impermeability, thus, having the possibility to specifically target the transmembrane CA IX that has an extracellular active site. Incorporation of radioactive copper isotopes in this type of CA inhibitor may lead to interesting diagnostic/therapeutic applications for such compounds.     

Development of Novel Quinoline-Based Sulfonamides as Selective Cancer-Associated Carbonic Anhydrase Isoform IX Inhibitors

A new series of quinoline-based benzenesulfonamides (QBS) were developed as potential carbonic anhydrase inhibitors (CAIs). The target QBS CAIs is based on the 4-anilinoquinoline scaffold where the primary sulphonamide functionality was grafted at C4 of the anilino moiety as a zinc anchoring group (QBS 13a–c); thereafter, the sulphonamide group was switched to ortho- and meta-positions to afford regioisomers 9a–d and 11a–g. Moreover, a linker elongation approach was adopted where the amino linker was replaced by a hydrazide one to afford QBS 16. All the described QBS have been synthesized and investigated for their CA inhibitory action against hCA I, II, IX and XII. In general, para-sulphonamide derivatives 13a–c displayed the best inhibitory activity against both cancer-related isoforms hCA IX (K_Is = 25.8, 5.5 and 18.6 nM, respectively) and hCA XII (K_Is = 9.8, 13.2 and 8.7 nM, respectively), beside the excellent hCA IX inhibitory activity exerted by meta-sulphonamide derivative 11c (K_I = 8.4 nM). The most promising QBS were further evaluated for their anticancer and pro-apoptotic activities on two cancer cell lines (MDA-MB-231 and MCF-7). In addition, molecular docking simulation studies were applied to justify the acquired CA inhibitory action of the target QBS.     

钕(Ⅲ)-氨基酸-邻菲啰啉三元配合物的合成及其抑菌活性

60℃下,在体积比为1∶1的乙醇水溶液中,采用常规溶液法合成了钕(Nd)-氨基酸-邻菲啰啉三元配合物。利用配合滴定、摩尔电导、红外光谱(IR)、热重-差热分析(TG-DTG)、紫外光谱(UV)和荧光光谱(FS)等分析手段对配合物的组成和光学等性质进行了分析与表征,推测系列配合物的化学组成为:[Nd(Amino)3Phen]Cl3.3H2O。通过抑菌实验对配合物的生物活性进行了研究。结果表明,组氨酸的羧基氧原子和邻菲啰啉的氮原子均与Nd3+配位,且配合物对大肠杆菌、枯草芽孢杆菌以及金黄色葡萄球菌有较好的抑菌效果。     

Cellular uptake, cytotoxicity, and metabolic profiling of human cancer cells treated with ruthenium(II) polypyridyl complexes [Ru(bpy)2(N--N)]Cl2 with N--N=bpy, phen, dpq, dppz, and dppn

A series of five ruthenium(II) polypyridyl complexes [Ru(bpy)2(N--N)]Cl2 was tested against human HT-29 and MCF-7 cancer cell lines. Cellular uptake efficiency and cytotoxicity were found to increase with the size of the aromatic surface area of the N--N ligand. The most active compound carrying the dppn ligand exhibits a low micromolar IC(50) value against both cell lines comparable to that of cisplatin under similar conditions. Continuous measurement of oxygen consumption, extracellular acidification rate, and impedance of the cell layer with a chip-based sensor system upon exposure to the complexes showed only small changes for the first two parameters throughout the series. A significant and irreversible decrease in impedance was, however, found for the dppn compound. This suggests that its biological activity is related to modifications in cell morphology or cell-cell and cell-matrix contacts.