Design,synthesis and biological evaluation of 4-aryl-5-aminoalkyl-thiazole-2-amines derivatives as ROCK II inhibitors

A series of 4-aryl-5-aminoalkyl-thiazole-2-amines were designed and synthesized, and their inhibitory activity on ROCK II was screened by enzyme-linked immunosorbent assay (ELISA). The results showed that 4-aryl-5-aminomethyl-thiazole-2-amines derivatives had certain ROCK II inhibitory activities. Compound 10l showed ROCK II inhibitory activity with IC₅₀ value of 20 nM.     

The role of 5′-methylthioadenosine phosphorylase in 5′-methylthioadenosine-mediated inhibition of lymphocyte transformation

To determine if increased 5′-methylthioadenosine phosphorylase activity in activated lymphocytes may be responsible for the decreased inhibitory effect noted when 5′-methylthioadenosine is added after stimulation, the activity of this enzyme was monitored during lymphocyte transformation. A direct correlation existed between the transformation process and 5′-methylthioadenosine phosphorylase activity; the longer the stimulation process progressed, the greater the enzyme activity. The 7-deaza analog of 5′-methylthioadenosine, 5′-methylthiotubercidin, was utilized to explore further the role that the phosphorylase may play in the reversal process. 5′-Methylthioadenosine acted as a potent inhibitor, but not a substrate, of the 5′-methylthioadenosine phosphorylase, and was an even more potent inhibitor of lymphocyte transformation than 5′-methylthioadenosine. However, in direct contrast to the 5′-methylthioadenosine effect, inhibition by 5′-methylthiotubercidin could not be completely reversed. These data suggest the 5′-methylthioadenosine phosphorylase plays an important role in reversing 5′-methylthioadenosine-mediated inhibition and that the potent, nonreversible inhibitory effects of 5′-methylthiotubercidin are due to its resistance to 5′-methylthioadenosine phosphorylase degradation.     

SAR comparative studies on pyrimido[4,5-b][1,4] benzothiazine derivatives as 15-lipoxygenase inhibitors, using ab initio calculations

The enzyme inhibitory activity of a new group of 2-substituted pyrimido[4,5-b][1,4]benzothiazines on soybean 15-lipoxygenase (15-LO) was evaluated and compared with those of their 4-methyl analogs using ab initio calculations. The results of these studies showed that the lack of 4-methyl substituent in the pyrimido[4,5-b][1,4] benzothiazine molecules greatly reduces their 15-LO inhibitory activities.     

Roles of GTP and GDP in the regulation of the thyroid adenylate cyclase system

Effects of guanine nucleotides on the adenylate cyclase activity of thyroid plasma membranes were investigated by monitoring metabolism of the radiolabeled nucleotides by thin-layer chromatography (TLC). When ATP was used as substrate with a nucleotide-regeneratign system, TSH stimulated the adenylate cyclase activity in the absence of exogenous guanine nucleotide. Addition of GTP and GDP equally enhanced the TSH stimulation. Effects of GTP and GDP were indistinguishable in regard to their inhibitory effects on NaF-stimulated activities. The results from TLC suggested that GDP could be converted to GTP by a nucleotide-regenerating system. Even in the absence of nucleotide-regenerating system, addition of GDP to the adenylate cyclase assay mixture int he parallel decrease in ATP levels and formation of GTP indicating that thyroid plasma membrane preparatiosn possessed a transphosphorylating activity. When an ATP analog, App[NH]p, was used as substrate without a nucleotide-regenerating system, no conversion of GDP to GTP was observed. Under such conditions, TSH did not stimulate the adenylate cyclase activity unless exogenous GTP or Gpp[NH]p was added. GDP no longer supported TSH stimulation and caused a slight decrease in the activity. GDP was less inhibitory than Gpp(NH)p to the NaF-stimulated adenylate cyclase activity. These results suggest: (1) TSH stimulation of thyroid adenylate cyclase is absolutely dependent on the regulatory nucleotides. (2) In contrst to GTP, GDP cannot support the coupling of the receptor-TSH complex to the catalytic componenet of adenylate cyclase. (3) The nucleotide regulatory site is more inhibitory to the stimulation of the enzyme by NaF when occupied by Gpp[NH]p than GDP.     

Spice phenolics inhibit human PMNL 5-lipoxygenase

A wide variety of phenolic compounds and flavonoids present in spices possess potent antioxidant, antimutagenic and anticarcinogenic activities. We examined whether 5-lipoxygenase (5-LO), the key enzyme involved in biosynthesis of leukotrienes is a possible target for the spices. Effect of aqueous extracts of turmeric, cloves, pepper, chili, cinnamon, onion and also their respective active principles viz., curcumin, eugenol, piperine, capsaicin, cinnamaldehyde, quercetin, and allyl sulfide were tested on human PMNL 5-LO activity by spectrophotomeric and HPLC methods. The formation of 5-LO product 5-HETE was significantly inhibited in a concentration-dependent manner with IC(50) values of 0.122-1.44 mg for aqueous extracts of spices and 25-83 microM for active principles, respectively. The order of inhibitory activity was of quercetin>eugenol>curcumin>cinnamaldehyde>piperine>capsaicin>allyl sulfide. Quercetin, eugenol and curcumin with one or more phenolic ring and methoxy groups in their structure showed high inhibitory effect, while the non-phenolic spice principle allyl sulfide showed least inhibitory effect on 5-LO. The inhibitory effect of quercetin, curcumin and eugenol was similar to that of synthetic 5-LO inhibitors-phenidone and NDGA. Moreover, the inhibitory potency of aqueous extracts of spice correlated with the active principles of their respective spices. The synergistic or antagonistic effect of mixtures of spice active principles and spice extracts were investigated and all the combinations of spice active principles/extracts exerted synergistic effect in inhibiting 5-LO activity. These findings clearly suggest that phenolic compounds present in spices might have physiological role in modulating 5-LO pathway.     

Inhibition of tubulin polymerization with ribose-modified analogs of GDP and GTP reduced inhibition with microtubule-associated proteins and magnesium

Inhibitory effects of ribose-modified GDP and GTP analogs on tubulin polymerization were examined to explore nucleotide structural requirements at the exchangeable GTP binding site. With microtubule-associated proteins and Mg²⁺, GTP-supported polymerization was only modestly inhibited by GDP, and still weaker inhibitory activity was found with two analogs, dGDP and 9-β-D-arabinofuranosylguanine-5′-diphosphate (araGDP). Omission of Mg²⁺ significantly enhanced the inhibitory effects of GDP, dGDP and araGDP and resulted in weak inhibition of the reaction by several other GDP analogs. The relative inhibitory activity of the GDP analogs had no discernable relationship to the relative activity of cognate GTP analogs in supporting microtubule-associated protein-dependent polymerization. One GTP analog, 2′,3′-dideoxyguanosine 5′-triphosphate (ddGTP), supports polymerization both with and without microtubule-associated proteins. The inhibitory activity of GDP and GDP analogs in ddGTP-supported polymerization was much greater in the absence of microtubule-associated proteins than in their presence; and both reactions were more readily inhibited than was microtubule-associated protein-dependent, GTP-supported polymerization. Microtubule-associated protein-independent, ddGTP-supported polymerization was also potently inhibited by GTP and a number of GTP analogs. GTP was in fact twice as inhibitory as GDP. The relative inhibitory activity of the GTP analogs was comparable to the relative inhibitory activity of the cognate GDP analogs and very different from their relative activity in supporting polymerization.     

硝基水杨酰胺抑制泛醌-细胞色素c还原酶的作用对氢醌的敏感性

泛醌－细胞色素ｃ还原酶（ＱＣＲ）是线粒体呼吸链的三个能量偶联部位之一,它起着将电子从还原型泛醌传递给细胞色素ｃ（Ｃｙｔ．ｃ）的作用,根据Ｋｉｎｇ和Ｙｕ提出的泛醌结合蛋白理论［１］,泛醌－细胞色素ｃ还原酶中含有泛醌结合蛋白ＱＰｃ．研究表明,泛醌－细胞色...     

Control of CO2 fixation. Regulation of spinach ribulose-5-phosphate kinase by stromal metabolite levels

The effect of stromal metabolites on the light-activated form of ribulose-5-phosphate kinase was studied with the enzyme rapidly extracted from illuminated spinach chlorplasts. In some instances, the effect of metabolites on the dark-inactivated enzyme extracted from darkened chloroplasts was also investigated. (1) The light-activated form of the enzyme is competitively inhibited with respect to ribulose 5-phosphate by 6-phosphogluconate, ribulose 1,5-bisphosphate, 3-phosphoglycerate and phosphate. Also, fructose 1,6-bisphosphate is inhibitory. All these compounds, except ribulose 1,5-bisphosphate, show an increasing inhibitory effect at lower pH values. Therefore, in the presence of these inhibitors, ribulose-5-phosphate kinase becomes strongly pH dependent. These compounds also exert an inhibitory effect on the dark-inactivated enzyme. (2) The assay of stromal levels of 6-phosphogluconate showed that this compound increased dramatically during a light-dark transient. (3) The dark-inactivated form of ribulose-5-phosphate kinase is strongly inhibited by ADP, the inhibition being competitive with respect to ATP. (4) A simulation of stromal metabolite levels in the enzyme activity assay indicates that in illuminated chloroplasts ribulose-5-phosphate kinase attains only about 4% of its maximal activity. When the fully light-activated enzyme is assayed under conditions occurring in the stroma in the dark, the activity is further decreased by a factor of 20. The same assay with the dark-inactivated enzyme yields an activity of virtually zero. (5) These results demonstrate that in the chloroplasts ribulose-5-phosphate kinase can not only be very efficiently switched off in the dark, but also be subjected to fine control during the illuminated state through the action of stromal metabolites.     

4-aminopyrimidine-5-carbaldehyde oximes as potent VEGFR-2 inhibitors. Part II

A series of 4-aminopyrimidine-5-carbaldehyde oxime was discovered to have potent VEGFR-2 inhibitory activity. Described here are the chemistry for analogue synthesis and SAR study results. The PK properties, kinase profiling, and in vivo efficacy study for compound 4b are also discussed.     

Increased inhibitory capacity of an anti-C5a complementary peptide following acetylation of N-terminal alanine

Amino acids 37 to 53 (RAARISLGPRCIKAFTE) of C5a anaphylatoxin form an essential region for C5a function. To target this sequence, we generated a complementary peptide (ASGAPAPGPAGPLRPMF) designated PepA which has a potent inhibitory effect on C5a activity. By introducing an acetyl group at the N-terminal alanine of PepA, an acetylated form was generated which was designated AcPepA. The acetylation resulted in increased inhibition of C5a stimulation of neutrophils as determined by Ca influx. Furthermore, AcPepA partially inhibited the lethal shock induced in mice by intravenous administration of Candida albicans water-soluble mannoprotein-beta-glucan complex. In addition, local skin inflammation in rats caused by an anti-Crry monoclonal antibody was suppressed when AcPepA and the antibody were injected together, while PepA had little inhibitory capacity. The potent inhibitory capacity of AcPepA was also confirmed by a skin reaction of guinea pigs inoculated with recombinant human C5a together with AcPepA.     

Synthetic studies on mitotic kinesin Eg5 inhibitors: Synthesis and structure–activity relationships of novel 2,4,5-substituted-1,3,4-thiadiazoline derivatives

The 2,4,5-substituted-1,3,4-thiadiazoline derivative 1a has been identified as a new class of mitotic kinesin Eg5 inhibitor. With the aim of enhancement of the mitotic phase accumulation activity, structure optimization of side chains at the 2-, 4-, and 5-positions of the 1,3,4-thiadiazoline ring of 1a was performed. The introduction of sulfonylamino group at the side chain at the 5-position and bulky acyl group at the 2- and 4-position contributed to a significant increase in the mitotic phase accumulation activity and Eg5 inhibitory activity. As a result, a series of optically active compounds exhibited an increased antitumor activity in a human ovarian cancer xenograft mouse model that was induced by oral administration.     

Increased efficacy of HIV-1 neutralization by antibodies at low CCR5 surface concentration

It has been observed that some antibodies, including the CD4-induced (CD4i) antibody IgG X5 and the gp41-specific antibody IgG 2F5, exhibit higher neutralizing activity in PBMC-based assays than in cell line based assays [J.M. Binley, T. Wrin, B. Korber, M.B. Zwick, M. Wang, C. Chappey, G. Stiegler, R. Kunert, S. Zolla-Pazner, H. Katinger, C.J. Petropoulos, D.R. Burton, Comprehensive cross-clade neutralization analysis of a panel of anti-human immunodeficiency virus type 1 monoclonal antibodies, J. Virol. 78 (2004) 13232-13252]. It has been hypothesized that the lower CCR5 concentration on the surface of the CD4 T lymphocytes compared to that on cell lines used for the neutralization assays could be a contributing factor to the observed differences in neutralizing activity. To test this hypothesis and to further elucidate the contribution of CCR5 concentration differences on antibody neutralizing activity, we used a panel of HeLa cell lines with well-defined and differential surface concentrations of CCR5 and CD4 in a pseudovirus-based assay. We observed that the CCR5 cell surface concentration but not the CD4 concentration had a significant effect on the inhibitory activity of X5 and several other CD4i antibodies including 17b and m9, as well as that of the gp41-specifc antibodies 2F5 and 4E10 but not on that of the CD4 binding site antibody (CD4bs), b12. The 50% inhibitory concentration (IC50) decreased up to two orders of magnitude in cell lines with low CCR5 concentration corresponding to that in CD4 T cells used in PBMC-based assays (about 10(3) per cell) compared to cell lines with high CCR5 concentration (about 10(4) or more). Our results suggest that the CCR5 cell surface concentration could be a contributing factor to the high neutralizing activities of some antibodies in PBMC-based-assays but other factors could also play an important role. These findings could have implications for development of vaccine immunogens based on the epitopes of X5 and other CD4i antibodies, for elucidation of the mechanisms of HIV-1 neutralization by antibodies, and for design of novel therapeutic approaches.     

酚类抑制剂抗5-脂氧合酶的分子对接研究

目的:研究抗5-脂氧合酶酚类抑制剂的结构活性关系及作用机制。方法:构建7个抗5-脂氧合酶阳性酚类抑制剂分子库,利用Autodock 4.2和iGEMDOCK 2.1软件包对受体与抑制剂进行模拟对接研究并计算结合自由能。结果:用Autodock 4.2、iGEMDOCK 2.1计算得到的结合自由能与抑制剂的抑制活性之间都存在良好的相关性,它们的决定系数(R2)依次为0.856 64和0.784 41,标准误差(SD)分别为0.430 92和5.323 35,P值分别为0.002 79和0.007 98;配体与受体之间形成的氢键在决定配体在受体活性部位的构象及定位中起重要作用,但两者结合的主要驱动力为范德华作用力;具有碳氧双键及与该双键共轭的碳碳双键的多环酚类化合物有较强的抗5-脂氧合酶活性。结论:Autodock 4.2比iGEMDOCK 2.1预测抗5-脂氧合酶酚类抑制剂的能力强;具有碳氧双键及与该双键共轭的碳碳双键的多环酚类化合物有较强的抗5-脂氧合酶活性。     

Discovery of 2-methyl-1-{1-[(5-methyl-1H-indol-2-yl)carbonyl]piperidin-4-yl}propan-2-ol: A novel,potent and selective type 5 17β-hydroxysteroid dehydrogenase inhibitor

Type 5 17β-hydroxysteroid dehydrogenase (17β-HSD5), also known as aldo-keto reductase 1C3 (AKR1C3), is a member of the aldo-keto reductase superfamily of enzymes and is expressed in the human prostate. One of the main functions of 17β-HSD5 is to catalyze the conversion of the weak androgen, androstenedione, to the potent androgen, testosterone. The concentration of intraprostatic 5α-dihydrotestosterone (DHT) in patients following chemical or surgical castration has been reported to remain as high as 39% of that of healthy men, with 17β-HSD5 shown to be involved in this androgen synthesis. Inhibition of 17β-HSD5 therefore represents a promising target for the treatment of castration-resistant prostate cancer (CRPC). To investigate this, we conducted high-throughput screening (HTS) and identified compound 2, which displayed a structure distinct from known 17β-HSD5 inhibitors. To optimize the inhibitory activity of compound 2, we first introduced a primary alcohol group. We then converted the primary alcohol group to a tertiary alcohol, which further enhanced the inhibitory activity, improved metabolic stability, and led to the identification of compound 17. Oral administration of compound 17 to castrated nude mice bearing the CWR22R xenograft resulted in the suppression of androstenedione (AD)-induced intratumoral testosterone production. Compound 17 also demonstrated good isoform selectivity, minimal inhibitory activity against either CYP or hERG, and enhanced pharmacokinetic and physicochemical properties.     

Coordination of the Rab5 cycle on macropinosomes

The GTPase Rab5a regulates the homotypic and heterotypic fusion of membranous organelles during the early stages of endocytosis. Many of the molecules which regulate the Rab5a cycle of association with membranes, activation, deactivation and dissociation are known. However, the extent to which these molecular scale activities are coordinated on membranes to affect the behavior of individual organelles has not been determined. This study used novel Förster resonance energy transfer (FRET) microscopic methods to analyze the Rab5a cycle on macropinosomes, which are large endocytic vesicles that form in ruffled regions of cell membranes. In Cos‐7 cells and mouse macrophages stimulated with growth factors, Rab5a activation followed immediately after its recruitment to newly formed macropinosomes. Rab5a activity increased continuously and uniformly over macropinosome membranes then decreased continuously, with Rab5a deactivation preceding dissociation by 1–12 min. Although the maximal levels of Rab5a activity were independent of organelle size, Rab5a cycles were longer on larger macropinosomes, consistent with an integrative activity governing Rab5a dynamics on individual organelles. The Rab5a cycle was destabilized by microtubule depolymerization and by bafilomycin A1. Overexpression of activating and inhibitory proteins indicated that active Rab5a stabilized macropinosomes. Thus, overall Rab5a activity on macropinosomes is coordinated by macropinosome structure and physiology.     

Design,synthesis and biological evaluation of tricyclic pyrazolo[1,5-c][1,3]benzoxazin-5(5H)-one scaffolds as selective BuChE inhibitors

Based on the structural analysis of tricyclic scaffolds as butyrylcholinesterase (BuChE) inhibitors, a series of pyrazolo[1,5-c][1,3]benzoxazin-5(5H)-one derivatives were designed, synthesized and evaluated for their acetylcholinesterase (AChE) and BuChE inhibitory activity. Compounds with 5-carbonyl and 7- or/and 9-halogen substitutions showed potential BuChE inhibitory activity, among which compounds 6a, 6c and 6g showed the best BuChE inhibition (IC₅₀?=?1.06, 1.63 and 1.63?µM, respectively). The structure–activity relationship showed that the 5-carbonyl and halogen substituents significantly influenced BuChE activity. Compounds 6a and 6g were found nontoxic, lipophilic and exhibited remarkable neuroprotective activity and mixed-type inhibition against BuChE (K_i?=?7.46 and 3.09?µM, respectively). Docking studies revealed that compound 6a can be accommodated into BuChE via five hydrogen bonds, one Pi–Sigma interaction and three Pi–Alkyl interactions.     

A Novel Labdane-Type Trialdehyde from Myoga (Zingiber mioga Roscoe) That Potently Inhibits Human Platelet Aggregation and Human 5-Lipoxygenase

We screened myoga extracts for inhibitors of human platelet aggregation and human 5-lipoxygenase. We identified a novel labdane type of diterpene, together with three known diterpenes (miogadial and galanals A and B) from the flower buds of myoga. Spectroscopic data indicated the structure of the new compound to be 12(E)-labdene-15,16,(8β)17-trial (miogatrial). Miogatrial and miogadial were potent inhibitors of human platelet aggregation and human 5-lipoxygenase (5-LOX). The sesquiterpene, polygodial, also exhibited strong inhibitory activity against human platelet aggregation and 5-LOX. On the other hand, galanals A and B did not have inhibitory activity in either experimental system. It thus appears that a 3-formyl-3-butenal structure was essential for the potent inhibition of human platelet aggregation and human 5-LOX.     

Design,synthesis and biological evaluation of hydroxy- or methoxy-substituted 5-benzylidene(thio) barbiturates as novel tyrosinase inhibitors

Here a new class of hydroxy- or methoxy-substituted 5-benzylidene(thio)barbiturates were designed, synthesized and their inhibitory effects on the diphenolase activity of mushroom tyrosinase were evaluated. The results showed that several compounds had more potent tyrosinase inhibitory activities than the widely used tyrosinase inhibitor kojic acid (IC₅₀ = 18.25 μM). In particular, 3′,4′-dihydroxylated 1e was found to be the most potent inhibitor with IC₅₀ value of 1.52 μM. The inhibition mechanism analysis revealed that the potential compounds 1e and 2e exhibited such inhibitory effects on tyrosinase by acting as the irreversible inhibitors. Structure–activity relationships’ (SARs) analysis also suggested that further development of such compounds might be of interest.     

Isolation and Biological Activity of Cyl-2, a Metabolite of Cylindrocladium scoparium

Three metabolites designated Cyl–1, –2 and –3 were isolated as plant growth regulators from culture filtrate of Cylindrocladium scoparium Morgan, a phytopathogenic fungus. Cy1–2 was obtained as pure crystals, and it revealed marked inhibitory activity on the root growth of lettuce seedlings. Cyl–1 showed inhibition on the same organ, while Cyl–3 showed promotion.     

The Regulation of Chlorophyll Biosynthesis by the Action of Protochlorophyllide on glut-RNA-Ligase

The pigment mutant C-2A' of the green alga Scenedesmus obliquus accumulates considerable amounts of protochlorophyllide (PChlide), when grown in darkness. In this paper it is demonstrated that the accumulated PChlide directly acts on ^glut-RNA-ligase and thereby blocks further biosynthesis of ALA and chlorophyll. By increasing the amount of ligase at constant concentrations of PChlide and ^glut-RNA it could clearly be demonstrated that PChlide directly inhibits ligase activity and does not act on the t-RNA. The inhibitory effect of other tetrapyrroles like chlorophyll a, pheophytin a and protoporphyrin IX was much less effective even at oversaturating concentrations.