Inhibition of Candida albicans isocitrate lyase activity by sesterterpene sulfates from the tropical sponge Dysidea sp

Seven sesterterpene sulfates (1-7) were isolated from the tropical sponge Dysidea sp. and their inhibitory activities against isocitrate lyase (ICL) from Candida albicans were evaluated. Among the isolated natural products compound 6 and 7 were found to be strong ICL inhibitors. The isolated compounds (1-7) also showed potent antibacterial effect against Bacillus subtilis and Proteus vulgaris, but did not display antifungal activity.     

Synthesis, biological evaluation, and molecular modeling of cinnamic acyl sulfonamide derivatives as novel antitubulin agents

A series of novel cinnamic acyl sulfonamide derivatives (9a-16e) have been designed and synthesized and their biological activities were also evaluated as potential tubulin polymerization inhibitors. Among all the compounds, 10c showed the most potent growth inhibitory activity against B16-F10 cancer cell line in vitro, with an IC(50) value of 0.8μg/mL. Docking simulation was performed to insert compound 10c into the crystal structure of tubulin at colchicine binding site to determine the probable binding model. Based on the preliminary results, compound 10c with potent inhibitory activity in tumor growth may be a potential anticancer agent.     

Human ACAT inhibitory effects of shikonin derivatives from Lithospermum erythrorhizon

Three naphthoquinones were isolated by bioassay-guided fractionation from the CHCl(3) extracts of roots of Lithospermum erythrorhizon. They were identified as acetylshikonin (1), isobutyrylshikonin (2), and beta-hydroxyisovalerylshikonin (3) on the basis of their spectroscopic analyses. The compounds 1-3 were tested for their inhibitory activities against human ACAT-1 (hACAT-1) or human ACAT-2 (hACAT-2). Compound 2 preferentially inhibited hACAT-2 (IC(50)=57.5microM) than hACAT-1 (32% at 120microM), whereas compounds 1 and 3 showed weak inhibitory activities in both hACAT-1 and -2. To develop more potent hACAT inhibitor, shikonin derivatives (5-11) were synthesized by semi-synthesis of shikonin (4), which was prepared by hydrolysis of 1-3. Among them, compounds 5 and 7 exhibited the strong inhibitory activities against hACAT-1 and -2. Furthermore, we demonstrated that compound 7 behaved as a potent ACAT inhibitor in not only in vitro assay system but also cell-based assay system.     

Synthesis, antibacterial activities and molecular docking studies of Schiff bases derived from N-(2/4-benzaldehyde-amino) phenyl-N'-phenyl-thiourea

A series of novel Schiff base derivatives have been designed and synthesized, and their biological activities were also evaluated as potential inhibitors of FabH. These compounds were assayed for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Compounds with potent antibacterial activities were tested for their E. coli FabH inhibitory activity. Compound 3v showed the most potent antibacterial activity with MIC of 1.56-6.25 μg/mL against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with IC(50) of 4.3 μM. Docking simulation was performed to position compound 3v into the E. coli FabH active site to determine the probable binding conformation.     

Synthesis, molecular modeling and biological evaluation of β-ketoacyl-acyl carrier protein synthase III (FabH) as novel antibacterial agents

A series of novel cinnamic acid secnidazole ester derivatives have been designed and synthesized, and their biological activities were also evaluated as potential inhibitors of FabH. These compounds were assayed for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Compounds with potent antibacterial activities were tested for their E. coli FabH inhibitory activity. Compound 3n showed the most potent antibacterial activity with MIC of 1.56-6.25 μg/mL against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with IC?? of 2.5 μM. Docking simulation was performed to position compound 3n into the E. coli FabH active site to determine the probable binding conformation.     

Hydrazones of 2-aryl-quinoline-4-carboxylic acid hydrazides: synthesis and preliminary evaluation as antimicrobial agents

A new series of 2-arylquinoline-4-carboxylic acid hydrazide–hydrazones was synthesized using an appropriate synthetic route. All the target compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus as an example for Gram-positive bacteria, Escherichia coli as an example for Gram-negative bacteria, and Candida albicans as a representative of fungi. The minimum inhibitory concentration (MIC) was determined for test compounds as well as for reference standards. Among the compounds tested, compounds having nitro substituents at the arylidene moiety showed the most potent antifungal as well as antibacterial activities against E. coli. Compound 23 displayed an antifungal activity comparable to that of nystatin. However, none of the compounds demonstrated any antibacterial activity against S. aureus. Hydrophobicity of the target compounds correlated weakly with their antibacterial and antifungal activities. The most potent compounds namely, 7, 18, 19, 22, and 23 were assessed for hemolytic toxicity and found to be non-hemolytic up to a concentration of 100 μg/mL. In addition, the most potent compound (23) was evaluated for in vitro cytotoxic activity against various cancer cell lines. This compound was found to display no cytotoxic activity but rather it induces the proliferation rate of Hep-G2 cells.     

Design, synthesis and biological evaluation of novel chalcone derivatives as antitubulin agents

A series of novel chalcone derivatives have been designed and synthesized, and their biological activities were also evaluated as potential inhibitors of tubulin. These compounds were assayed for growth-inhibitory activity against MCF-7 and A549 cell lines in vitro. Compound 3d showed the most potent antiproliferative activity against MCF-7 and A549 cell lines with IC(50) values of 0.03 and 0.95 μg/mL and exhibited the most potent tubulin inhibitory activity with IC(50) of 1.42 μg/mL. Docking simulation was performed to insert compound 3d into the crystal structure of tubulin at colchicines binding site to determine the probable binding model. Based on the preliminary results, compound 3d with potent inhibitory activity in tumor growth may be a potential anticancer agent.     

Synthesis,computational studies and antiproliferative activities of coumarin-tagged 1,3,4-oxadiazole conjugates against MDA-MB-231 and MCF-7 human breast cancer cells

A novel library of coumarin tagged 1,3,4 oxadiazole conjugates was synthesized and evaluated for their antiproliferative activities against MDA-MB-231 and MCF-7 breast cancer cell lines. The evaluation studies revealed that compound 9d was the most potent molecule with an IC₅₀ value of <5?µM against the MCF-7 cell line. Interestingly, compounds 10b and 11a showed a similar trend with lower inhibitory concentration (IC₅₀?=?7.07?µM), in Estrogen Negative (ER?) cells than Estrogen Positive (ER+) cells. Structure–activity relationship (SAR) studies revealed that conjugates bearing benzyl moieties (9b, 9c and 9d) had superior activities compared to their alkyl analogues. The most potent compound 9d showed ～1.4?times more potent activity than tamoxifen against MCF-7 cell line; while the introduction of sulfone unit in compounds 11a, 11b and 11c resulted in significant cytotoxicity against both MCF-7 and MDA-MB-231 cell lines. These results were further supported by docking studies, which revealed that the stronger binding affinity of the synthesized conjugates is due to the presence of sulfone unit attached to the substituted benzyl moiety in their pharmacophores.     

Design, synthesis and antitumor activities of novel bis-aryl ureas derivatives as Raf kinase inhibitors

A series of novel bis-aryl ureas containing trifluoromethyl imidazolyl group targeting Raf kinase were designed and synthesized based on the lead compound of Sorafenib. All the prepared compounds were evaluated for their in vitro antiproliferative activities against three human cancer cell lines including MDA-MB-231 (breast), BGC-823 (gastric), and SMMC-7721 (liver). Several compounds from the series exhibited excellent antitumor activities against all three tested cancer lines. Further their inhibitory activities against Raf kinase were investigated, and three compounds (11c, 11d, and 11p) demonstrated better activities than contrast drug Sorafenib. Especially compound 11c was found to be a potent and selective Raf kinase inhibitor and could be considered as a candidate compound for further development.     

Design,synthesis and evaluation of carbazole derivatives as potential antimicrobial agents

Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 µg/ml. Compounds 8f and 9d showed the most potent inhibitory activities (MICs of 0.5–2 µg/ml). Furthermore, compounds 8b, 8d, 8f, 8k, 9b and 9e with antimicrobial activities were not cytotoxic to human gastric cancer cell lines (SGC-7901 and AGS) or a normal human liver cell line (L-02). Structure–activity relationship analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency and reducing the toxicity of the carbazole compounds. In vitro enzyme activity assays suggested that compound 8f binding to dihydrofolate reductase might account for the antimicrobial effect.     

A facile solid-state synthesis and in vitro antimicrobial activities of some 2,6-diarylpiperidin/tetrahydrothiopyran and tetrahydropyran-4-one oximes

Some 2,6-diarylpiperidin/tetrahydrothiopyran/tetrahydropyran-4-one oximes were synthesized in dry media under microwave irradiation and were evaluated for their in vitro antibacterial activity against clinically isolated bacterial strains i.e. S.aureus, beta-H.Streptococcus, E.coli, P.aeruginosa, S.typhii and in vitro antifungal activities against fungal strains i.e. C.albicans, Rhizopus, A.niger and A.flavus. Structure-activity relationships for the synthesized compounds showed that compounds 12 and 15 exerted excellent antibacterial activity against all the tested bacterial strains except 15 against S.aureus and beta-H.streptococcus. Against C.albicans and A.flavus, compound 15 exerted potent antifungal activities while against Rhizopus, compound 16 showed promising activity.     

Radical scavenging and cytochrome P450 3A4 inhibitory activity of bergaptol and geranylcoumarin from grapefruit

Grapefruit juice has been shown to increase the oral bioavailability of several clinically important drugs by inhibiting first pass metabolism. Several compounds in grapefruit juice have shown different biological activities. Unique among them are furocoumarins with potent inhibitory activity against cytochrome P450 enzymes. In the present study, two bioactive compounds were isolated from grapefruit juice and grapefruit peel oil. The purity of the isolated compounds has been analyzed by HPLC. Structures of the compounds were elucidated by extensive NMR and mass spectral studies and identified as bergaptol and geranylcoumarin. The isolated compounds were tested for their radical scavenging activity using 2,2'-azobis (3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazil (DPPH) methods at different concentrations. Bergaptol showed very good radical scavenging activity at all the tested concentrations. Furthermore, these compounds were evaluated for their inhibitory activity against CYP3A4 enzyme. Bergaptol and geranylcoumarin were found to be potent inhibitors of debenzylation activity of CYP3A4 enzyme with an IC(50) value of 24.92 and 42.93 microM, respectively.     

Beta-lactam congeners of orlistat as inhibitors of fatty acid synthase

Beta-lactam derivatives of orlistat were prepared and their inhibitory activities toward the thioesterase domain of fatty acid synthase (FAS-TE) were evaluated using a recombinant form of the enzyme. While in general these derivatives showed lower potency compared to beta-lactones, a reasonably potent, lead compound (-)-9 (IC(50)=8.6microM) was discovered that suggests that this class of compounds should be evaluated further.     

Synthesis and antitumor activity of 1,2,4-triazoles having 1,4-benzodioxan fragment as a novel class of potent methionine aminopeptidase type II inhibitors

A series of 1,2,4-triazole derivatives containing 1,4-benzodioxan (5a-5q) have been designed, synthesized, structurally determined, and their biological activities were evaluated as potential MetAP2 inhibitors. All the synthesized compounds were first reported. Among the compounds, compound 5k showed the most potent biological activity against HEPG2 cancer cell line (IC(50)=0.81 μM for HEPG2 and IC(50)=0.93 μM for MetAP2), which was comparable to the positive control. Docking simulation by positioning compound 5k into the MetAP2 structure active site was performed to explore the possible binding model. The results of apoptosis and Western-blot assay demonstrated that compound 5k possessed good antitumor activity against HEPG2 cancer cell line. Therefore, compound 5k with potent inhibitory activity in tumor growth inhibition may be a potential antitumor agent against HEPG2 cancer cell.     

Design, synthesis, and biological evaluation of imidazoline derivatives as p53-MDM2 binding inhibitors

Three series of novel imidazoline derivatives were designed, synthesized, and evaluated for their p53-MDM2 binding inhibitory activities, and anti-proliferation activities against PC3, A549, KB, and HCT116 cancer cell lines. Five of the tested compounds showed enhanced p53-MDM2 binding inhibitory potency and anti-proliferation activities in comparison with that of Nutlin-1. Flow cytometric analysis indicated that compound 7c, one of the most potent p53-MDM2 binding inhibitors with a K(i) value of 0.6 μM, showed its ability to arrest cell cycle progression.     

Synthesis and acrosin inhibitory activity of substituted 4-amino-N-(diaminomethylene) benzenesulfonamide derivatives

A series of new substituted 4-amino-N-(diaminomethylene) benzenesulfonamides were synthesized and their in vitro acrosin inhibitory activities were evaluated. Most of the compounds showed potent acrosin inhibitory activities with compounds 4o and 4p being significantly more potent than the control compound N-alpha-tosyl-l-lysyl-chloromethyl-ketone (TLCK). The compounds provide a new scaffold for the development of acrosin inhibitory agents.     

Analogues of antifungal tjipanazoles from rebeccamycin

Analogues of antifungal tjipanazoles were obtained by semi-synthesis from rebeccamycin, an antitumor antibiotic isolated from cultures of Saccharothrix aerocolonigenes. The antiproliferative activities of the new compounds were evaluated in vitro against nine tumor cell lines. The effect on the cell cycle of murine leukemia L1210 cells was examined and the antimicrobial activities against two Gram positive bacteria, a Gram negative bacterium and a yeast were determined. The inhibitory properties toward four kinases and toward topoisomerase I were evaluated. The most cytotoxic compound in the series was a dinitro derivative characterized as a potent topoisomerase I inhibitor.     

Biological evaluation of new antitumor taxoids: Alteration of substitution at the C-7 and C-10 of docetaxel

A series of new docetaxol analogues have been designed and synthesized. And their cytotoxicities against cancer cells have been evaluated by MTT method. Most of these compounds showed selective inhibitions on human cancer cell lines. Among them, compound 8 exhibited higher inhibitory activity than Paclitaxel (Taxol) against several cancer cell lines. This work indicated that appropriate modification at C-7 and C-10 of docetaxel might be a promising approach for this unique class of anticancer compounds.     

极地真菌Geomyces pannorum SA3-2-YM次级代谢产物的研究

采用聚酰胺柱层析、硅胶柱层析、反相硅胶柱层析、凝胶柱层析和高效液相HPLC等色谱技术,对极地真菌Geomyces parmorum SA3-2-YM的发酵液提取物进行分离纯化,共得到13个化合物,通过NMR和MS等波谱数据确定结构为:cyclo-(L-Trp-L-Pro)(1)、cyclo-(L-Trp-L-Tyr)(...     

Urease inhibitory activity of simple alpha,beta-unsaturated ketones

A variety of alpha,beta-unsaturated ketones were evaluated for their effect on the jack bean urease. Of 35 compounds tested, 2-cyclohepten-1-one (1), 2-cyclohexen-1-one (2), 2-cyclopenten-1-one (3), and 5,6-dihydro-2H-pyran-2-one (4) showed potent inhibitory activities against the enzyme. The most potent compound (1) (IC50=0.16 mM) showed similar inhibitory potency to hydroxyurea (IC50=0.095 mM). The inhibitory effects of 1, 2, 3, and 4 were significantly reduced by 2-mercaptoethanol or dithiothreitol. These data suggest that alpha,beta-unsaturated ketones inhibited the urease activity, possibly by a Michael-like addition of a protein SH group to the double bond of the alpha,beta-unsaturated carbonyl group.