Novel coumarin derivatives containing 1,2,4-triazole, 4,5-dicyanoimidazole and purine moieties: synthesis and evaluation of their cytostatic activity

We report here on the synthesis and in vitro anti-tumor effects of a series of novel 1,2,4-triazole (compounds 3-6), 4,5-dicyanoimidazole (compound 7), and purine (compounds 8-13) coumarin derivatives and their acyclic nucleoside analogues 14-18. Structures of novel compounds 3-18 were deduced from their ¹H- and ¹³C-NMR and corresponding mass spectra. Results of anti-proliferative assays performed on a panel of selected human tumor cell lines revealed that compound 6 had moderate cytostatic activity against the HeLa cell line (IC₅₀ = 35 μM), whereas compound 10 showed moderate activity against the HeLa (IC₅₀ = 33 μM), HepG2 (IC₅₀ = 25 μM) and SW620 (IC₅₀ = 35 μM) cell lines. These compounds showed no cytotoxic effects on normal (diploid) human fibroblasts.     

Concise Synthesis and Antidiabetic Effect of Three Natural Triterpenoid Saponins Isolated from Fadogia ancylantha (Makoni tea)

The first concise synthesis of the bidesmosidic oleanolic acid saponins 1 – 3 isolated from Fadogia ancylantha (Makoni tea) have been accomplished through a ‘one‐pot sequential glycosylation’ strategy with two glycosyl 1‐(trichloroacetimidate)s as glycosyl donors. The synthesized natural products 1 – 3 were then evaluated for their inhibitory activities against α‐glucosidase, α‐amylase, and lipase. Among the assayed compounds 1 – 3 , compound 1 showed strong α‐glucosidase and α‐amylase inhibition, with IC₅₀ values of 160 and 180 μM , respectively. Moreover, compounds 2 and 3 showed strong inhibition against α‐glucosidase and lipase, with the respective IC₅₀ values of 170 and 190 μM , and 190 and 200 μM .     

Cytotoxic Amides and Quinolones from Clausena lansium

Two new amides, claulansamides A and B ( 1 and 2 , resp.), together with five known amides, 3 – 7 and six known quinolones, 8 – 13 , were isolated from the stems and roots of Clausena lansium. Their structures were elucidated on the basis of extensive spectroscopic methods. Their absolute configurations were determined by single‐crystal X‐ray diffraction technique, CD, and optical rotation. HPLC Chiral separation of 1 afforded two enantiomers, (+)‐ and (?)‐claulansamide A, respectively. Compounds 9, 12 , and 13 were isolated from the genus Clausena for the first time. All compounds were evaluated for their cytotoxic activities against A549, BGC‐823, and HeLa cancer cell lines. However, only 9 showed cytotoxic activity against A549 cell line with an IC₅₀ value of 46.3 μM , and 11 against BGC‐823 and HeLa cell lines with the IC₅₀ values of 55.0 and 14.7 μM , respectively.     

Synthesis and Biological Activity of Some New Pyrazole Copper(II) Complexes

As a part of systematic investigation of synthesis and biologically active compounds of pyrazole derivatives containing transition metal, several new pyrazole copper(II) complexes 3a?f were synthesized from pyrazole sodium salts 2a?f , which were produced from spiro‐pyrazoles 1a?f and sodium hydride by a ring‐opening reaction. All the synthesized compounds were characterized by spectroscopic analysis. Pyrazole copper(II) complexes 3a?d and 3f exhibited high DNA cleavage activity in vitro. Furthermore, compounds 3a?f were tested for their growth inhibitory activity in A549 lung cancer, B16F10 murine melanoma, and HeLa human uterine carcinoma cells. Compounds 3c,d displayed moderate B16F10 and HeLa inhibitory activity levels ( 3c : IC₅₀ = 45 μM in B16F10 cells and 34 μM in HeLa cells, 3d : IC₅₀ = 50 μM in B16F10 cells and 32 μM in HeLa cells).     

Enzymatic Synthesis of Novel Bavachinin Glucoside by UDP‐glycosyltransferase

Bavachinin, a member of the flavanone subclass of flavonoids, has long been considered to have various biological activities. Here, the synthesis of novel bavachinin glucoside by the in vitro glycosylation reaction was successfully achieved using a UDP‐glucosyltransferase YjiC, from Bacillus licheniformis DSM‐13. The chemical structure of bavachinin glucoside was characterized based on spectroscopic techniques as bavachinin‐4′‐O‐ß‐D‐glucopyranoside ( 1 ). The water‐solubility of bavachinin‐4′‐O‐ß‐D‐glucopyranoside was found to be 9.96 μM, about 10 times higher than bavachinin. In addition, compound 1 showed moderate anti‐proliferative activity against four human tumor cell lines, with IC₅₀ values ranging from 48.5 to 61.4 μM.     

Design and Synthesis of New Chacones Substituted with Azide/Triazole Groups and Analysis of Their Cytotoxicity Towards HeLa Cells

A series of new chalcones substituted with azide/triazole groups were designed and synthesized, and their cytotoxic activity was evaluated in vitro against the HeLa cell line. O-Alkylation, Claisen-Schmidt condensation and Cu(I)-catalyzed cycloaddition of azides with terminal alkynes were applied in key steps. Fifteen compounds were tested against HeLa cells. Compound 8c was the most active molecule, with an IC₅₀ value of 13.03 μM, similar to the value of cisplatin (7.37 μM).     

Synthesis,in vitro Antimicrobial,and Cytotoxic Activities of New 1,3,4‐Oxadiazin‐5(6H)‐one Derivatives from Dehydroabietic Acid

A series of new 1,3,4‐oxadiazin‐5(6H)‐one derivatives ( 6a–n ) of dehydroabietic acid were designed and synthesized as potential antimicrobial and antitumor agents. Their structures were characterized by IR, ¹H NMR, ¹³C NMR, MS, and elemental analyses. All the title compounds were evaluated for their antimicrobial activity against four bacterial and three fungal strains using the serial dilution method. Among them, compound 6e showed the highest antibacterial activity against Bacillus subtilis with a minimum inhibitory concentration (MIC) value of 1.9 μg/mL. In addition, the in vitro cytotoxic activities of the title compounds were also assayed against three human carcinoma cell lines (MCF‐7, SMMC‐7721, and HeLa) through the MTT colorimetric method. As a result, compounds 6b , 6g , 6k, and 6m exhibited significant inhibition against at least one cell line with IC₅₀ values below 10 μM. Compound 6m was especially found to be the most potent derivative with IC₅₀ values of 2.26 ± 0.23, 0.97 ± 0.11, and 1.89 ± 0.31 μM against MCF‐7, SMMC‐7721, and HeLa cells, respectively, comparable to positive control etoposide.     

Morpholino‐Functionalized and Heteroaryl‐Substituted Titanocene Anti‐Cancer Drugs: Synthesis and Cytotoxicity Studies

From the carbolithiation of 6‐morpholino fulvene ( 3a ) and different ortho‐lithiated heterocycles (furan, thiophene and N‐methylpyrrole), the corresponding lithium cyclopentadienide intermediate ( 4a – c ) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl₄ resulting in morpholino‐functionalised titanocenes 5a – c . When these titanocenes were tested against LLC‐PK cells, the IC₅₀ values obtained were of 58, 63 and 115 μM for titanocenes 5a – c respectively. The most cytotoxic titanocene 5a with an IC₅₀ value of 58 μM is found to be approximately 20 times less cytotoxic than cis‐platin, which showed an IC₅₀ value of 3.3 μM, when tested on the LLC‐PK cell line, and 10 times less cytotoxic than its dimethylamino‐functionalised analogue (Titanocene C , IC₅₀ = 5.5 μM).     

A Novel Xanthone from Garcinia oligantha

One novel xanthone, oliganthone A ( 1 ), was isolated from the stems of the plant Garcinia oligantha. It features the O‐bearing C(3)‐atom and absence of C(4) compared with the structures of related known xanthones, which have never been reported before. The structure of this compound was elucidated by spectroscopic analysis. Compound 1 showed strong HeLa cell growth‐inhibiting effects with IC₅₀ values below 10 μM .     

Synthesis of novel triazoloquinoxaline-pyrazole hybrids as antiproliferatives,EGFR inhibitors,and apoptosis inducers

Novel triazoloquinoxaline-pyrazole hybrids have been developed and synthesized. All derivatives' anticancer activity has been evaluated using Sulforhodamine-B (SRB) assay for cancer cell lines MCF-7, HepG-2, and HCT-116. Compound 12b was 2-fold more cytotoxic than Doxorubicin, while 12a , c demonstrated comparable cytotoxicity to the reference Doxorubicin. Further investigations on the most active derivatives 12a-c were done to study their inhibitory activity on two EGFR subtypes wild EGFR and mutant EGFR (L858R) tyrosine kinases in MCF-7 cell lines. Compound 12b exhibited potent inhibitory activity toward wild EGFR (IC₅₀: 0.98 μM) when compared to Gefitinib (IC₅₀:18.07 μM). 12b also possessed a marked inhibition against mutant EGFR (L858R-TK) exhibiting (IC₅₀:27.45 μM) in comparison to Lapatinib (IC₅₀: 61.06 μM). Compound 12b improved the active Caspase-3 value and the BAX/Bcl-2 reference. Furthermore, 12b showed G2/M cell cycle arrest induced apoptosis in cell line MCF-7. In addition, the most active derivatives have been orally bioavailable as shown in the in silico determination of the ADME characters. The binding pattern of compound 12b was also studied by molecular docking.     

Peripheral or nonperipheral tetra‐[4‐(9H‐carbazol‐9‐yl)phenoxy] substituted cobalt(II), manganese(III) phthalocyanines: Synthesis,acetylcholinesterase, butyrylcholinesterase,and α‐glucosidase inhibitory effects and anticancer activities

In this work, peripheral or nonperipheral tetra‐[4‐(9H‐carbazol‐9‐yl)phenoxy] substituted cobalt(II), manganese (III) phthalocyanines were synthesized for the first time. Their acetylcholinesterase from Electrophorus electricus (AChE), butyrylcholinesterase equine serum (BuChE), and α‐glucosidase Saccharomyces cerevisiae inhibition were investigated spectrophotometrically. Finally, in vitro cytotoxicities of the compounds were investigated on human neuroblastoma (SH‐SY5Y) cell line using MTT cell viability assay. The compounds inhibited to enzymes in the range of 7.39 ± 0.25–35.29 ± 2.49 μM with IC₅₀ values for AChE and 14.38 ± 0.66–58.02 ± 4.94 μM for BuChE as compared with galantamine, which used as a positive control. For α‐glucosidase, all compounds had stronger inhibition action than acarbose according to the IC₅₀ values. The IC₅₀ values of N? Co and N? Mn were found to be 3.05 ± 0.10 and 15.82 ± 1.85 μM, respectively. The results of cytotoxicity showed that the IC₅₀ values were above 100 μM showing the compounds had low cytotoxic action against SH‐SY5Y cell line for 24 h. Overall, carbazole substituted nonperipheral compounds can be considered as a potential agent for the treatment of Alzheimer's diseases and diabetes mellitus.     

New stigmastane type of steroidal glycosides from the roots of Vernonia cumingiana

Two new stigmastane type of steroidal glycosides, vernoniacums A and B (1 and 2), with a △7,9(11) steroidal core were isolated from the roots of Vernonia cumingiana. Their structures were elucidated based on various spectroscopic techniques, including IR, HR-FAB-MS, and 1D and 2D NMR. Both compounds were evaluated for their cytotoxicity against HeLa and HCT-8 cells, and compound 1 showed mild activity against the tested cell lines with IC50 values of 15.8 and 35.7 pounds were evaluated for their cytotoxicity against HeLa and HCT-8 cells, and compound 1 showed mild activity against the tested cell lines with IC₅₀ values of 15.8 and 35.7 μM, respectively.     

Design,synthesis, anticancer activity,and in silico studies of novel imidazo[1,2-a]pyridine based 1H-1,2,3-triazole derivatives

A novel series of imidazo[1,2-a]pyridine based 1H-1,2,3-triazole derivatives were designed, synthesized, and evaluated for their anticancer activity against two different human cancer cell lines. Most of the synthesized compounds displayed anticancer activity with IC₅₀ values from 2.35 to 120.46 μM. Furthermore, compounds 9b , 9c, 9d, 9f , and 9j showed potent inhibitory activity against cancer cell lines, with IC₅₀ values close to that of standard drug. It is important to note that compound 9d was more potent than the standard drug cisplatin with IC₅₀ values of 10.89 and 2.35 μM against Hela cell line and MCF-7 cell line, respectively.     

Synthesis and antiviral activity of novel imidazo[2,1-b]thiazoles coupled with morpholine and thiomorpholines

Herein described the synthesis and antiviral evaluation of a novel series of morpholine and thio-morpholine coupled imidazo[2,1-b]thiazoles. The three-step reaction sequence involving the condensation of 1,3-dichloroacetone with thiourea followed by coupling with morpholine and thiomorpholine and finally cyclization with substituted α-bromoacetophenones yielded the desired imidazothiazoles 7(a–l) . Screening of all the new compounds for their in vitro antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) in MDCK cells, resulted in two potent analogs, 7d (IC₅₀: 1.1 μM, C₅₀: >300 μM, SI = 273) and 7e (IC₅₀: 2.0 μM, C₅₀: >300 μM, SI = 150), with a favorable toxicity profile and are the best anti-influenza hit analogs for further structural optimization.     

Cyclometalated Ruthenium(II) Anthraquinone Complexes Exhibit Strong Anticancer Activity in Hypoxic Tumor Cells

Hypoxia is the critical feature of the tumor microenvironment that is known to lead to resistance to many chemotherapeutic drugs. Six novel ruthenium(II) anthraquinone complexes were designed and synthesized; they exhibit similar or superior cytotoxicity compared to cisplatin in hypoxic HeLa, A549, and multidrug‐resistant (A549R) tumor cell lines. Their anticancer activities are related to their lipophilicity and cellular uptake; therefore, these physicochemical properties of the complexes can be changed by modifying the ligands to obtain better anticancer candidates. Complex 1 , the most potent member of the series, is highly active against hypoxic HeLa cancer cells (IC₅₀=0.53 μM ). This complex likely has 46‐fold better activity than cisplatin (IC₅₀=24.62 μM ) in HeLa cells. This complex tends to accumulate in the mitochondria and the nucleus of hypoxic HeLa cells. Further mechanistic studies show that complex 1 induced cell apoptosis during hypoxia through multiple pathways, including those of DNA damage, mitochondrial dysfunction, and the inhibition of DNA replication and HIF‐1α expression, making it an outstanding candidate for further in vivo studies.     

Total Synthesis,Absolute Configuration,and Biological Activity of Xyloallenoide A

The novel natural product xyloallenoide A, isolated from the marine mangrove endophytic fungus from the South China Sea, and its diastereoisomer xyloallenoide A1, which contain N‐methyl‐substituted amino acids, were synthesized. The absolute configurations of the amino acid units of xyloallenoide A were finally confirmed to be L ‐Lys, Me‐D ‐Val, and Me‐L ‐Ala. This report represents a practical and attractive alternative for the synthesis of N‐methyl‐substituted cyclotripeptides. In the preliminary bioassay, synthetic xyloallenoide A showed marginal activities against KB (IC₅₀=9.6 μM ) and KBv200 cells (IC₅₀=10.3 μM ), and xyloallenoide A1 was inactive against KB and KBv200 cells.     

Synthesis of non-toxic anticancer active forskolin-indole-triazole conjugates along with their in silico succinate dehydrogenase inhibition studies

Biologically important three different pharmacophores, forskolin, indole and 1,2,3-triazoles are coupled to obtain a hybrid molecule. Here, we described the synthesis of novel series of forskolin-indole-triazole conjugates 5a-5l by using the Cu(I) catalyzed 1,3-dipolar cycloaddition reaction. Furthermore, the biological significance of the synthesized molecules was assessed by in silico and in vitro modes. All the synthesized compounds were evaluated for in vitro anticancer activity against PC-3, MCF-7, MDA-MB-231, COLO-205, HeLa, WRL-68, RAJI, CHANG and RAW-264.7 cell lines. Compound 5g was found to be the most potent in all the tested cell lines (IC₅₀ range 9.6–21.66 μg/ml, except COLO-205), 5a, 5b and 5k were observed to exert its effect only against WRL-68 (IC₅₀ range 27.69–48.18 μg/ml), when compared to parent 3 (IC₅₀ > 100 μg/ml, tested concentrations 10–50 μg/ml) and standard Doxorubicin (IC₅₀ range 0.42–3.16 μg/ml). The most potent compound 5g (MEF₅₀ 0.57) was found non-toxic to human erythrocytes as compared to control (MEF₅₀ 0.60) at tested concentration (50 μg/ml). In silico-based succinate dehydrogenase inhibition showed that the synthesized compounds were having potent binding affinity compared to forskolin. Predictive ADMET and toxicity risk assessment analysis revealed that most of the compounds were complying with the standard limit of Lipinski's rule of five for oral bioavailability.     

Synthesis and anticancer activity of benzotriazole derivatives

A series of benzotriazole (BTA) derivatives were synthesized as tyrosine protein kinase inhibitors using fragment-based design strategy. All desired compounds were synthesized with the reaction of benzotriazole, chloroacetonitrile and aromatic aldehyde using Ultrasonic-Microwave method and characterized by IR, ¹H and ¹³C-NMR, mass spectrometry (MS) and elemental analysis. The anticancer activity of these compounds was evaluated by CCK-8 method against carcinoma VX2, lung cancer A549, stomach cancer cell lines MKN45 and MGC in vitro. The results showed that all compounds showed good antiproliferative activity. In particular, compound 2.1 showed the most prominent inhibition of VX2 cell lines with IC₅₀ of 3.80 ± 0.75 μM. Compound 2.2 exhibited highly potent anticancer activity of stomach MGC cell lines with IC₅₀ of 3.72 ± 0.11 μM. A549 and MKN45 cell lines were sensitive to compound 2.5 with IC₅₀ of 5.47 ± 1.11 and 3.04 ± 0.02 μM, respectively.     

Bisubstrate Inhibitors for the Enzyme Catechol O‐Methyltransferase (COMT): Dramatic Effects of Ribose Modifications on Binding Affinity and Binding Mode

Inhibition of the enzyme catechol O‐methyltransferase (COMT) is of significant interest in the therapy of Parkinson's disease. Described herein are structural analogs of the potent bisubstrate inhibitor (?)‐ 1 (IC₅₀=9 nM ; Table 1) for COMT, with target modifications of the central ribose moiety. Their synthesis involves, as key intermediates, adenosine derivatives, which are transformed to the potential bisubstrate inhibitors by a similar sequence of six steps (Schemes 1–4). The compounds were submitted to an enzymatic assay for determination of their in vitro inhibitory activity against COMT, and the inhibition mechanism with respect to the binding side of the cofactor S‐adenosylmethionine (SAM) was analyzed by kinetics measurements (Fig. 3). Both binding affinity and binding mode were exceedingly sensitive towards modifications of the ribose moiety (Table 1). Removal of the 2′‐OH group upon changing from (?)‐ 1 to (?)‐ 2 (IC₅₀=28 μM ) led to a reduction in binding affinity by more than three orders of magnitude. At the same time, competitive inhibition kinetics with respect to the SAM binding site was maintained, thereby supporting a bisubstrate binding mode. Unlike (?)‐ 2 , the dideoxyribose inhibitor (?)‐ 3 (IC₅₀=3 μM ) showed a mixed and the cyclopentane derivative (+)‐ 4 (IC₅₀=1 μM ) an uncompetitive inhibition mechanism with respect to the SAM binding site. In the complex of the latter, the adenine‐substituted cyclopentane ring orients most probably towards the surface of the enzyme into the surrounding solution. The enantiomeric compounds (?)‐ 5 (IC₅₀=43 μM ) and (+)‐ 5 (IC₅₀=141 μM ), wherein the ribose had been replaced by a pyrrolidine ring, showed only low binding affinity.     

Synthesis and Transformation of 4-(1-Chloro-1-nitroethyl)-6,7-dimethoxy-2-methylquinazoline: Spectral Characterization and Anti-cancer Properties of some Novel Quinazoline Derivatives

An efficient and simple method has been reported for the synthesis of 4-(1-Chloro-1-nitroethyl)-6,7-dimethoxy-2-methylquinazoline ( 2 ) as a key compound for further transformation to other novel 6,7-dimethoxy-2-methyl-4-substituted quinazolines. The structure of the synthesized compounds was characterized by spectroscopic methods. The pathway of some unprecedented reactions was proposed. (E)-1-(6,7-dimethoxy-2-methylquinazolin-4-yl)-3-(4-nitrophenyl)prop-2-en-1-one (11) exhibits high in vitro cytotoxicity on three cell lines, Hepatocellular carcinoma (Hep-G2), Human lung carcinoma (LU-1), and Human breast carcinoma (MCF-7) with IC₅₀ of 2.1, 11.6 and 2.2 μM, respectively.