Use of RP-HPLC for Purification of a CCK-39 Radio-Ligand and of Its Photoactivable Derivative. Controls of Degradations

Abstract

In order to characterize CCK receptors on guinea-pig pancreatic acini we developped a method of purification and control of degradation of CCK-39 radio-ligands and of their photoactivable derivatives. CCK-39 was radio-labeled with N-hydroxysuccinimide 3-(4-hydroxy 5 [¹²⁵I] phenyl) propionate at pH=8.5. Mono-labeled CCK-39 was separated from di-and tri-labeled CCK-39 on a C-18 column and coupled with N-hydroxysuccinimidyl-4-azido-benzoate. The resulting photoactivable radio-ligand ¹²⁵I-BH-[4-azidobenzoyl]-CCK-39 specifically bound to pancreatic membranes. After photolysis under UV irradiation and SDS-PAGE a major labeled protein of Mr 90 000 could be identified. Furthermore, RP-HPLC permitted the control of degradation of each ligand. Presence of endo-peptidasic and aminopeptidasic activities sensitive to EDTA and bacitracin were demonstrated.     

Potentiated effect of vagal stimulation and hormonal agents on pancreatic exocrine secretion in dogs

Chronic experiments were made on eighteen dogs with Thomas pancreatic fistula and gastric fistula. Both in chronic and acute experiments the degenerated right cervical vagus nerve was stimulated by electrical shock and the endogenous secretin and CCK was released by means of duodenal acidification (D. A.). The exogenous secretin, atropine and lidocaine were infused to analyse the interrelationship of neurohormones in the pancreatic exocrine secretion. The results were as follows. In chronic experiments the pancreatic secretory latency was shorter and volume larger than that in acute experiments induced by D. A. The difference is very significant (P less than 0.001). Both vagotomy and atropine significantly inhibited pancreatic secretion induced by D. A. (P less than 0.01). Lidocaine infused into duodenum inhibited pancreatic secretion induced by D. A. as well. When vagal stimulation was combined with D. A., either simultaneously or successively, the pancreatic secretion was increased more than the additive sum obtained by separate action of vagal stimulation and D. A. or secretin. In view of the above-mentioned facts, the author suggests that vagal impulses combined with D. A. or secretin act on the pancreatic exocrine secretion, and that the interaction of nerve and hormones appear to be mutually potentiated.     

苯并吡喃-4-脲、硫脲和氰胍类化合物的合成及其血管舒张活性

钾通道开放剂;苯并吡喃-4-脲、硫脲和氰胍类化合物的合成及其血管舒张活性     

Synthesis and antiulcer activity of 4-substituted 8-[(2-benzimidazolyl)sulfinylmethyl]-1,2,3,4-tetrahydroquinoli nes and related compounds

A series of 4-substituted 8-[(2-benzimidazolyl)sulfinylmethyl]-1,2,3,4-tetrahydroquinolin es was synthesized and examined for their (H+ + K+)adenosine triphosphatase (ATPase)-inhibitory and antisecretory activities against histamine-induced gastric acid secretion in rats. Many compounds tested were potent inhibitors of (H+ + K+)ATPase. Most compounds showed antisecretory activity. The antiulcer activity against water-immersion stress-induced gastric ulcer, aspirin-induced gastric ulcer and gastric necrosis induced by hydrochloric acid also were tested in the rat. Some of these compounds, in particular, 4-(N-allyl-N-methylamino)-1-ethyl-8-[(5-fluoro-6-methoxy-2-benzimidazoly l) sulfinylmethyl]-1-ethyl-1,2,3,4-tetrahydroquinoline (XVIIx) were found to have potent activity. The structure-activity relationships are discussed.     

Investigation of new bifunctional agents: D-Penicillamine

Somatostatin inhibits the release of growth hormone (somatotropin) from the Anterior Pituitary. The main use of derivatives of somatostatin is to diagnose growth hormone problems and to use against some forms of cancer which involve growth hormone. Also somatostatin suppresses gastric acid secretion, gallbladder contractions, and pancreatic enzyme secretion. The aim of the current study is to investigate new bifunctional agents for labeling with ^99mTc. Therefore D-Penicillamine was used as a bifunctional agent and compared to DTPA in the labeling with ^99mTc. Quality controls were established using thin layer radio chromatography (TLRC) and electrophoresis techniques. In addition, high performance liquid radio chromatography (HPLRC) was also performed for elimination of possible uncertainties. The radiolabeled complexes maintained their stabilities throughout the study. The results obtained showed that ^99mTc-D-Penicillamine-somatostatin is a promising potential radiopharm aceutical and an alternative of ^99mTc-DTPA-somatostatin for in vivo and in vitro applications.     

Structure-activity relationships of rat neuromedin U for smooth muscle contraction.

Rat neuromedin U (r-NMU) and its fragment peptide amides were synthesized by solid-phase methodology. Using a chicken crop smooth muscle contraction assay, the potency of r-NMU and its fragments relative to porcine neuromedin U-8 (p-NMU-8) was r-NMU: 10.25 +/- 2.88, r-NMU (6-23): 8.01 +/- 1.04, r-NMU (10-23): 2.76 +/- 0.46, r-NMU (13-23): 2.81 +/- 0.52, and r-NMU (16-23): 0.88 +/- 0.19, respectively. Two heptapeptides, r-NMU (17-23) and r-NMU (16-22), had a relative potency of 0.61 and 0.03 respectively, and elicited maximal contraction at a dose of 10 microM to a similar degree to p-NMU-8. The other shorter C-terminal fragments did not elicit the maximal contraction or any activity. In a rat uterus contraction assay, r-NMU (13-23), but not r-NMU (16-23), at a dose of 4 nM retained as high a stimulatory activity as r-NMU itself. r-NMU (17-22) was the smallest peptide fragment to elicit the maximal sustained contraction at 10 microM. These results indicate that the amino acid sequence Phe-Leu-Phe-Arg-Pro-Arg, corresponding to positions 17 to 22 of r-NMU, may be essential for contractile activity. N-terminal peptide segments Tyr-Gln-Gly-Pro corresponding to positions 6 to 9, and Ser-Gly-Gly corresponding to positions 13 to 15, appear to be of special importance for potent activity.     

New mu-opioid receptor agonists with phenoxyacetic acid moiety

New muq-opioid receptor (MOR) agonists containing 4-hydroxypiperidine, piperidine and piperazine moieties were synthesized and evaluated to find a peripheral opioid analgesic. Among the synthesized compounds, 12-[1-[3-(N,N-dimethylcarbamoyl)-3,3-diphenylpropyl]-4-hydroxypiperidin-4-yl]phenoxy]acetic acid (8: SS620) having phenoxyacetic acid and 4-hydroxypiperidine moieties showed the highest agonist potency on the MOR in an isolated guinea-pig ileum preparation, and it also had selectivity to the human MOR expressed in Chinese hamster ovary (CHO)-K1 cells compared with the same types of delta- and kappa-opioid receptors (DOR and KOR). In addition, compound 8 showed a 10 times more potent MOR agonist activity than loperamide. Furthermore, compound 8 showed a peripheral analgesic activity in vivo screening on rat.     

Inhibition of gastric H+, K(+)-ATPase activity by compounds from medicinal plants

H+, K(+)-ATPase enzyme is a therapeutic target for the treatment of gastric disturbances. Several medicinal plants and isolated compounds inhibit the acid gastric secretion through interaction with the proton pump. In order to add new properties to some natural constituents, five compounds, a benzylated derivative of vincoside, a diterpene (abietic acid) and three alkaloids (cephaeline, vinblastine and vindoline), were tested for their activities on gastric H+, K(+)-ATPase isolated from rabbit stomach. All the compounds inhibited H+, K(+)-ATPase activity with varied potency. The IC50 value for benzylvincoside was 121 (50-293) microM, and for abietic acid 177 (148-211) microM. The alkaloids cephaeline, vinblastine and vindoline inhibited the H+, K(+)-ATPase activity with IC50 values of 194, 761 and 846 microM, respectively. The results suggest that benzylvincoside, abietic acid and cephaeline can be important sources for the development of anti-secretor agents.     

汉防己甲素衍生物的合成及其生物活性

为寻找更为有效的抗肿瘤药物,改善汉防己甲素的抗肿瘤活性,本文以汉防己甲素为原料,经过Suzuki反应设计并合成了6个新的双苄基异喹啉类衍生物。新化合物经过质谱(MS)、核磁共振氢谱(~1H NMR)、核磁共振碳谱(~(13)C NMR)等技术手段进行了结构确证。采用细胞计数试剂盒(CCK-8)法初步评价了6个新化合物对人肺癌细胞(A549)和小鼠白血病细胞(P388)的抗肿瘤活性。结果表明,化合物均有不同程度的抗肿瘤活性,其中化合物H1、H4、H6对A549细胞的抗肿瘤活性(IC5010μmol/L)明显优于阳性对照汉防己甲素。     

Design and Synthesis of Pyrido[1,2-e]purin-4（3H）-one Derivatives as Potential PDE 5 Inhibitors

A novel series of pyrido[ 1,2-e]purin-4（3H）-one derivatives containing polar substituents on 5＇-position were designed and prepared as potential PDE5 inhibitors. This paper reports the synthetic routes, 1H-NMR data, and the PDE5 inhibitory activities of the target compounds. The polar piperazinyl group contained （on 5＇-position） compound, 3B2, showed the highest activity among the tested derivatives but less potency than sildenafil 1.     

Synthesis of new cardioselective M2 muscarinic receptor antagonists

A series of 5H-dibenz[b,f]azepine derivatives was prepared and evaluated for binding affinities to muscarinic receptors in vitro. Among them, compound 8 showed a high affinity for human recombinant M2 receptors (Ki=2.6 nm), a low affinity for M4 receptors (39-fold less than for M2 receptors) and a very low affinity for M1 and M3 receptors (119- and 112-fold less than for M2 receptors, respectively). The high M2 selectivity of 8 may be attributed to the olefinic bond of the azepine ring. Functional experiments showed 8 to be a competitive antagonist with high affinity to the cardiac (pA2=7.1) and low affinity to the intestinal muscarinic receptors (IC50=0.54 microM). In vivo experiments confirmed the in vitro M, selectivity of 8. Acetylcholine-induced bradycardia was dose-dependently antagonized in rats after both intravenous and intraduodenal administration of 8. In rats, cholinergic functions mediated by M1 or M3 receptors (salivary secretion, pupil diameter, gastric emptying, intestinal transit time) were not affected by the oral administration of 8 even at doses as high as 30 times the antibradycardic effective dose. Furthermore, 8 had no analgesic activity in mice, indicating poor central nervous system penetration. In dogs, nocturnal bradycardia was dose-dependently inhibited by the oral route with a duration of action of about 24 h. Compound 8 appears to be a promising cardioselective antimuscarinic agent for the treatment of dysfunctions of the cardiac conduction system such as sinus or nodal bradycardia ("sick-sinus syndrome") and atrioventricular block.     

High-performance capillary electrophoretic analysis of hyaluronan and galactosaminoglycan-disaccharides in gastrointestinal carcinomas. Differential disaccharide composition as a possible tool-indicator for malignancies

The glycosaminoglycans (GAGs) have documented implications for the growth and progression of malignant tumors. Gastrointestinal carcinomas (gastric, colon, rectum and pancreatic) are the most frequent malignancies occurring in human. GAGs, isolated from the tissues after digestion with papain, were analyzed by high-performance capillary electrophoresis (HPCE) following treatment with chondroitinase ABC. The composition of GAGs in disaccharides derived from the various gastrointestinal carcinomas was compared with those of normal tissues. We report that human gastrointestinal carcinomas are characterized by increased concentrations of GAGs, which have quite different disaccharide composition which, in turn, is associated with marked increase of non-sulfated (Delta(di)-nonS) and 6-sulfated (Delta(di)-mono6S) Delta-disaccharides. Particularly, a 12-51-fold increase in Delta(di)-nonS and a 3-42-fold increase in Delta(di)-mono6S content characterize these carcinomas, while the 4-sulfated units (Delta(di)-mono4S) showed a lower increase, about 0.5-1.5-fold. Moreover, the quantitation of hyaluronan (HA)-derived Delta-disaccharides (Delta(di)-nonS(HA)) also revealed a marked increase (1-12-fold) in the malignant tissues. On the other hand, the content of the chondroitinase ABC-resistant GAGs showed a low decrease, about 0.2-0.7-fold. The high amounts of hyaluronan (HA) produced by these carcinomas and the ectopic production of chondroitin sulphate (CS) proteoglycans, in which (Delta(di)-nonS) and (Delta(di)-mono6S) predominated, suggest a close relation between the content of these GAGs and the malignant phenotype, the metastatic ability and the survival time.     

High performance liquid chromatographic determination of methylxanthines in canine serum, gastric and pancreatic juices

A convenient high performance liquid chromatographic method for the determination of methylxanthines in biological samples is described. Separation was achieved by reversed phase chromatography using a mobile phase consisting of tetrahydrofuran + methanol + 0.01M potassium dihydrogen phosphate, pH 3.5 (1:20:79, v/v/v), on a 7 microns C18 column and a C18 Lichrosorb precolumn at a flow rate of 0.8 mL/min. Levels varying from 0.25-16 mg/L could be detected by UV at 280 nm. In this range, standard curves were established for 4 methylxanthines: theobromine, paraxanthine, theophylline and caffeine in 4 media: mobile phase, serum, gastric and pancreatic juices, and were found to be linear (r greater than or equal to 0.9975). Overall characteristics of the method were determined as: percent recovery (89.54%), accuracy (greater than or equal to 99.4%) and reproducibility (greater than or equal to 95%). Retention times ranged from 4.21 +/- 0.01 (1-methyluric acid) to 10.8 +/- 0.03 min (caffeine). Animal experiments (5 and 10 mg/kg boluses) were used to determine caffeine half life in dog's blood (310 +/- 46 and 453 +/- 59 min, respectively) and its secretion into pentagastrin stimulated gastric juice (mean concentrations 2.51 and 6.04 mg/L; mean outputs 351 and 1206 micrograms/2.25 h; both statistically different at p less than 0.001 level).     

Synthesis and in vitro antibacterial activity of 7-(3-amino-6,7-dihydro-2-methyl-2H-pyrazolo[4,3-c] pyridin-5(4H)-yl)fluoroquinolone derivatives

A series of novel 7-(3-amino-6,7-dihydro-2-methyl-2H-pyrazolo[4,3-c]pyridin- 5(4H)-yl)fluoroquinolone derivatives were designed, synthesized and characterized by 1H-NMR, MS and HRMS. These fluoroquinolones were evaluated for their in vitro antibacterial activity against representative Gram-positive and Gram-negative strains. Results reveal that most of the target compounds exhibit good growth inhibitory potency against methicillin-resistant Staphylococcus epidermidis (MRSE) (MIC: 0.25-4 μg/mL) and Streptococcus pneumoniae (MIC: 0.25-1 μg/mL). In addition, compound 8f is 8-128 fold more potent than the reference drugs gemifloxacin (GM), moxifloxacin (MX), ciprofloxacin (CP) and levofloxacin (LV) against methicillin-resistant Staphylococcus aureus 10-05 and Streptococcus hemolyticus 1002 and 2-64 fold more active against methicillin-sensitive Staphylococcus aureus 10-03 and 10-04.     

Studies on analgesic oligopeptides. VI. Further studies of synthesis and biological properties of tripeptide alkylamides, Tyr-D-Arg-Phe-X

Nine analogs based on a structure of Tyr-D-Arg-Phe-X (X = alkylamides or alkylhydrazide containing electron-withdrawing atoms or groups) were newly synthesized and their biological properties were examined by the opioid receptor binding properties of mu-, delta- and kappa-receptors, guinea-pig ileum (GPI) assay and analgesic activity in the tail pinch test after subcutaneous administration in mice. Analogs with X = NHCF2CF3, Sar-ol, or NH(CH2)2CN showed potent activities in the GPI and analgesic assays and high affinity for mu-receptor. An analog with X = taurinamide was found to possess 4-fold higher mu-receptor selectivity than that of [D-Ala2, MePhe4, Gly-ol5]enkephalin (DAGO). The receptor binding properties of previously reported analogs [Chem. Pharm. Bull., 33, 1528 (1985); ibid., 33, 4865 (1985); ibid., 36, 4834 (1988)] were also examined for overall discussion of the structure-activity relationships of this series of tripeptide amides.     

Structure-activity relationship of yohimbine and its related analogs in blocking alpha-1 and alpha-2 adrenoceptors: a comparative study of cardiovascular activities

We investigated the selectivities and structure requirements for alpha-1 and alpha-2 adrenoceptor blocking activities of yohimbine (YO) and its 12 related analogs, such as beta-yohimbine (beta-YO), dihydrocorynantheine (DHC) and (-)indoloquinolizidine ((-)IQ). The affinity of YO analogs to alpha-adrenoceptor was assessed by measuring their blockade of pressor responses to epinephrine in pithed rats. Among YO structure groups, the potency order was YO greater than DHC = beta-YO greater than geissoschizine methylether greater than 14 beta-hydroxy YO greater than 14 beta-benzoyloxy YO (inactive). (-)IQ was slightly less potent than YO, but much stronger than (+)IQ. Among (+/-)IQ structure groups, the potency order was (+/-)IQ greater than (+/-)1,12b-trans-1-hydroxy IQ much greater than (+/-)1,12b-cis-1-hydroxy IQ (inactive). (+/-)Borrerine was active, but (+/-)desmethylborrerine was inactive. The alpha-1 blocking activities of the four compounds YO, beta-YO, DHC and (-)IQ, were assessed in experiments of pressor responses to methoxamine in pithed rats and contractile responses to methoxamine in the rat vas deferens. The potency order was (-)IQ greater than YO greater than DHC greater than beta-YO. Furthermore, the alpha-2 blocking activities of the four analogs were assessed in experiments of pressor responses to clonidine and inhibition of electrically driven cardioacceleration by clonidine, in pithed rats. The potency order was YO greater than beta-YO greater than (-)IQ greater than DHC. Based on the potency ratio between alpha-1 and alpha-2 blocking activities, DHC or YO was most selective for alpha-1 or alpha-2 subtype, respectively, among the four YO analogs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Potent Dual BET/HDAC Inhibitors for Efficient Treatment of Pancreatic Cancer

As one of the most aggressive and lethal human malignancies with extremely poor prognosis, there is an urgent demand of more effective therapy for the treatment of pancreatic cancer. Reported here is a new, effective therapeutic strategy and the design of small‐molecule inhibitors that simultaneously target bromodomain and extra‐terminal (BET) and histone deacetylase (HDAC), potentially serving as promising therapeutic agents for pancreatic cancer. A highly potent dual inhibitor ( 13 a ) is identified to possess excellent and balanced activities against BRD4 BD1 (IC₅₀=11 nm ) and HDAC1 (IC₅₀=21 nm ). Notably, this compound shows higher in vitro and in vivo antitumor potency than the BET inhibitor (+)‐JQ1 and the HDAC inhibitor vorinostat, either alone or and in combination, highlighting the advantages of BET/HDAC dual inhibitors for more effective treatment of pancreatic cancer.     

Further studies on the anti-ulcerogenic effects of compound, 2-(E-2-decenoylamino)ethyl 2-(cyclohexylethyl) sulfide.

Tha anti-ulcerogenic mechanism of 2-(E-2-decenoylamino)ethyl 2-(cyclohexylethyl) sulfide (compd. III-1a) was investigated in various gastric defensive factors. Compound III-1a maintained the high molecular glycoprotein (relative content of Fr. I hexose) and accelerated hexosamine synthesis which were reduced by water immersion stress. But plaunotol did not have these actions. The lipid peroxide level in the gastric mucosa from water immersion stressed rat was lowered by the administration of compd. III-1a. Compound III-1a maintained prostaglandin E2 (PGE2) and PGI2 contents which were reduced in the early phase of the stress and accelerated PGs synthesis in the late phase of the stress. Furthermore, compd. III-1a maintained phospholipase A2 (PLA2) activity which was reduced by the stress. The plaunotol treated group showed the same tendency as the compd. III-1a treated group on the lipid peroxide level, PGE2 and PGI2 contents, and PLA2 activity, but the potency of plaunotol was less than that of compd. III-1a. Compound III-1a accelerated gastric cell proliferation in pyloric glands of hydrocortisone treated rats. Tetragastrin accelerated significantly the cell proliferation in fundic glands. The sucralfate treated group showed the same tendency as the compd. III-1a treated group but the potency of sucralfate was less than that of compd. III-1a. The results in the present study suggest that compd. III-1a has a protective action on gastric mucosa.     

新型汉防己甲素衍生物的合成及其生物活性

以汉防己甲素为原料,经溴代反应制得关键中间体5-溴汉防己甲素(2); 2与硼酸衍生物经Suzuki反应合成了6个新型的汉防己甲素衍生物(4a~4f),其结构经¹H NMR, ¹³C NMR和ESI-MS表征。采用CCK-8法初步考察了4a~4f对人早幼粒白血病细胞(HL60)和人肺癌细胞(A549)的抑制活性;并采用MTT法对活性较好的化合物进行复筛。采用酶联免疫吸附法考察4a~4f对多种受体酪氨酸激酶的抑制活性。结果表明：4b, 4c和4e对HL60和A549有一定的抑制活性; 4b和4c对受体酪氨酸激酶FGFR1的抑制活性大于50%。     

Agents for the treatment of overactive detrusor. I. Synthesis and structure-activity relationships of 1,1'-biphenyl derivatives.

A series of 1,1'-biphenyl-2,6-dicarboxylic acid diesters were synthesized and examined for their inhibitory activity on guinea-pig detrusor muscle contraction at electrical field stimulation in vitro. Among them, 6-isopropyl 2-methyl 3-hydroxy-5-methyl-2'-nitro-(1,1'-biphenyl)-2,6-dicarboxylate, FR75513 (8a) was one of the potent compounds (IC50 = 3.3 x 10(-6) g/ml). This compound (8a) exhibited a strong inhibitory activity on detrusor contraction after intravenous administration in anesthetized rats (ID50 = 0.04 mg/kg).