Synthesis, antiplatelet aggregation activity, and molecular modeling study of novel substituted-piperazine analogues

Abstract  

New carbamoylpyridine and carbamoylpiperidine analogues containing nipecotic acid scaffold were designed, synthesized, and evaluated for their platelet aggregation inhibitory activity. Molecular modeling investigation was performed and the impact of lipophilicity on activity was also discussed. Structure activity relationship among this series was obtained. N ¹-[1-(4-bromobenzyl)-3-piperidino-carbonyl]-N ⁴-(2-chlorophenyl)-piperazine hydrobromide (20), and 1,4-bis-[3-[N ⁴-(2-chlorophenyl)-N ¹-(piperazino-carbonyl)]-piperidin-1-yl-methyl]-benzene dibromide (30) are the most active antiplatelet aggregating compounds in this study, both at concentration of 0.06 μM.     

Design and synthesis of novel N-substituted-3-chloro-2-azetidinone derivatives as potential anticonvulsant agents

Abstract  

A new series of N-[3-chloro-2-(substitutedphenyl)-4-oxo-azetidin-1-yl]isonicotinamide (2a–l) were synthesized through condensation reaction of isoniazide with substituted aldehyde. The newly synthesized compounds were characterized by spectral data (IR, ¹H NMR, mass spectra) and elemental analysis. Compound 2e exhibited excellent anticonvulsant activity and no neurotoxicity in comparison to reference drug phenytoin.     

Ginsenoside Rh2-mediated G1 Phase Cell Cycle Arrest in Human Breast Cancer Cells Is Caused by p15Ink4B and p27Kip1-dependent Inhibition of Cyclin-dependent Kinases

Purpose  

Present study was undertaken to gain insights into the mechanism of cell cycle arrest by ginseng saponin ginsenoside Rh2 (Rh2) using MCF-7 and MDA-MB-231 breast cancer cells.     

A1-and A2-PURINOCEPTORS IN THE GUINEA-PIG UTERUS

1. Radioligand binding and functional studies were undertaken to investigate the P₁-purinoceptors present in the separated myometrial layers and the endometrium of the guinea-pig uterus. 2. In preparations of endometrium-denuded circular myometrium, the A₂-selective agonists (2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamido-adenosine (CGS 21680, 100 μmol/L) and N-ethylcarboxamido adenosine (NECA, 1–10 μmol/L) inhibited contractile responses to phenylephrine. In preparations of endometrium-intact circular myometrium, NECA (10 μmol/L) enhanced responses to phenylephrine. NECA did not modulate the spontaneous contractions of longitudinal myometrium. 3. Homogenate binding studies with circular myometrium, longitudinal myometrium and endometrium revealed saturable high affinity [³H]-NECA binding sites. The mean maximal densities of binding sites (B_max) were 2.08, 14.7 and 15.5 fmol/mg protein, and pK_D (neg. log dissociation constant) values were 9.82, 9.19 and 7.44, respectively. 4. (R-) and (S-) -N⁶-(2-phenylisopropyl)adenosine (R- and S-PIA) both competed for two [³H]-NECA binding sites in preparations of circular myometrium. CGS 21680 competed for two [³H]-NECA binding sites in preparations of endometrium and longitudinal myometrium. All other agonist competition was for one site only. The rank orders of potency of high affinity binding were S-PIA ≥ R-PIA ≥ CGS 21680 (circular myometrium), R-PIA ≥ CGS 21680 ≥ S-PIA (longitudinal myometrium) and CGS 21680 > > S-PIA ≥ R-PIA (endometrium). 5. In preparations of circular myometrium, longitudinal myometrium and endometrium the selective A₁-purinoceptor antagonist, 1,3-dipropyl-8-(2-amino-4-chloro)-phenylxanthine (PACPX), competed for two [³H]-NECA binding sites, the non-selective antagonist 3,7-dimethyl-1-propargylxanthine (DMPX), competed for one site only. 6. NECA increased cyclic adenosine monophosphate (CAMP) levels in preparations of both circular myometrium and endometrium. 7. These results indicate that P₁-purinoceptors of the A₂-subtype mediate the inhibitory effects of adenosine analogues on the phenylephrine-induced contractions of the circular myometrium of the guinea-pig, this effect is modified by the presence of the endometrium. There is no evidence that the [³H]-NECA binding sites of the longitudinal myometrium correlate with functional P₁-purinoceptors in this tissue.     

NMDA receptor/nitrergic system blockage augments antidepressant-like effects of paroxetine in the mouse forced swimming test

Objective  

In this study, we evaluated the involvement of N-methyl-d-aspartate receptor (NMDAR)/nitric oxide (NO) system on the antidepressant-like effects of paroxetine in the mouse forced swimming test.     

药用库拉索芦荟活性多糖的护肤特性研究

目的 研究库拉索芦荟多糖的保湿特性、经皮吸收特性以及皮肤安全性。方法 采用超声辅助提取芦荟活性多糖,并通过人体皮肤水分含量和水分散失量测试法对所制备的芦荟活性多糖的保湿特性（包括锁水、保水两个方面）进行评价;Franz扩散池体外透皮吸收法评价其透皮吸收特性;人体斑贴试验评价其皮肤安全性。结果 与空白对照组比较,库拉索芦荟多糖可显著提高皮肤水合状态（P＜0.05）,同时降低经皮失水（P＜0.05）;多糖质量浓度为5%时,皮肤渗透速率达到0.251 0 mg/(h?cm²),24 h累计渗透量达（4.151 9±0.046 2）mg/cm²;人体皮肤斑贴试验中全部评定为0级反应。结论 库拉索芦荟活性多糖对皮肤具有显著的保湿功效以及较强的皮肤渗透力,并且高度安全,可作为优良的保湿添加剂在化妆品等肤用产品中广泛应用。     

N6-苯甲酰基-2'-叔丁基二甲基硅氧基腺苷-3'-H-膦酸的合成工艺研究

目的 研究N~6-苯甲酰基-2′-叔丁基二甲基硅氧基腺苷-3′-H-膦酸的合成工艺。方法 以腺苷为起始原料,先对腺苷的嘌呤氨基进行苯甲酰基保护,再分别向腺苷的5′位和2′位引入二甲氧基三苯甲基(DMT)和叔丁基二甲基硅基(TBDMS)保护基,制备得到关键中间体N~6-苯甲酰基-5′-二甲氧基三苯甲氧基-2′-叔丁基二甲基硅氧基腺苷(3)。中间体3与磷试剂2-氯-4H-1,3,2-苯并二氧磷杂环己烷-4-酮反应引入膦酸基团,最后使用二氯乙酸脱除DMT保护基得到目标产物。结果 经过5步反应得到了目标化合物N~6-苯甲酰基-2′-叔丁基二甲基硅氧基腺苷-3′-H-膦酸,并利用~1H-NMR、~(31)P-NMR、质谱等方法确证了其结构。本合成工艺的总收率为35.7%,目标化合物的质量分数为98.5%。结论 该合成工艺与原有方法相比步骤短,操作简单,具有良好的应用前景。     

COMPARISON OF RESPONSES TO AMINOGUANIDINE AND Nω-NITRO-L-ARGININE METHYL ESTER IN THE RAT AORTA

1. We have compared the effect of aminoguanidine with that of N^ω-nitro-L-arginine methyl ester on isolated thoracic aortic rings obtained either from endotoxin (lipopolysaccharide, 10 mg/kg, i.v. for 3 h) or vehicle (saline) treated rats. 2. Administration of endotoxin for 3h resulted in a hypo tension and a significant reduction of pressor responses to nor-epinephrine (1 μg/kg, i.v.) in the anaesthetized rat. 3. In intact rings obtained from vehicle treated rats, amino guanidine (0.3 and 1mmol/L) had no significant effect on acetylcholine-induced relaxation (10^-9–10^-5mol/L), whereas N^ω-nitro-L-arginine methyl ester (0.3mmol/L and 1mmol/L) abolished that response, suggesting that aminoguanidine does not inhibit the activity of constitutive nitric oxide synthase. 4. Relaxation induced by L-arginine (10^-6–10^-2mol/L) was competitively inhibited by both aminoguanidine (0.3 mmol/L) and N^ω-nitro-L-arginine methyl ester (0.3 mmol/L) in endo thelium-denuded aortic rings obtained from endotoxin treated rats. 5. Three hours of endotoxaemia was associated with an impairment of contraction to norepinephrine (10^-9–10^-6 mol/L) in the endothelium-denuded aorta ex vivo. This hyporeactivity to norepinephrine was partially restored by treatment of the vessels either with aminoguanidine (0.3 mmol/L) or with N^ω-nitro-l-arginine methyl ester (0.3 mmol/L) in vitro. 6. These results in isolated thoracic aortae of the rat reinforce that aminoguanidine is a selective inhibitor of the inducible nitric oxide synthase, whereas N^ω-nitro-L-arginine methyl ester is a non-selective inhibitor of both the inducible and constitutive nitric oxide synthase.     

Interaction of mGlu2/3 agonism with clozapine and lurasidone to restore novel object recognition in subchronic phencyclidine-treated rats

Rationale  

Subchronic administration to rodents of the N-methyl-d-aspartate non-competitive antagonist, phencyclidine (PCP), impairs novel object recognition (NOR). Atypical antipsychotic drugs (APDs) reverse the effects of subchronic PCP on NOR. The effect of metabotropic glutamate_2/3 receptor (mGlu_2/3) agonists upon NOR is unknown.     

Very Long Chain N 4 ,N 9 -Diacyl Spermines: Non-Viral Lipopolyamine Vectors for Efficient Plasmid DNA and siRNA Delivery

Purpose

To study the effect of increasing the chain length over C-18 and varying the oxidation level in synthesized N ⁴,N ⁹-diacyl spermines on DNA and siRNA formulation, and then to compare their transfection efficiency in cell lines

Methods

The five novel very long chain N ⁴,N ⁹-diacyl polyamines: N ⁴,N ⁹-[diarachidoyl, diarachidonoyl, dieicosenoyl, dierucoyl and dinervonoyl]-1,12-diamino-4,9-diazadodecane were synthesized. The abilities of these novel compounds to condense DNA and to form nanoparticles were studied using ethidium bromide fluorescence quenching and nanoparticle characterization techniques. Transfection efficiency was studied in FEK4 primary skin cells and in an immortalized cancer cell line (HtTA), and compared with the non-liposomal transfection formulation Lipogen, N ⁴,N ⁹-dioleoyl-1,12-diamino-4,9-diazadodecane. Also, the abilities of these compounds to condense siRNA and to form nanoparticles were studied using a RiboGreen intercalation assay and their abilities to deliver siRNA into cells were studied in FEK4 and HtTA cells using fluorescein-labelled Label IT® RNAi Delivery Control, a sequenced 21-mer from Mirus.

Results

We show efficient pEGFP and siRNA formulation and delivery to primary skin and cancer cell lines.

Conclusions

Adding two C20 or C22 chains, both mono-cis-unsaturated, N ⁴,N ⁹-dieicosenoyl spermine and N ⁴,N ⁹-dierucoyl spermine, gave efficient siRNA delivery vectors, even in the presence of serum, comparable to TransIT-TKO and with excellent cell viability.     

Pharmacology of ayahuasca administered in two repeated doses

Rationale  

Ayahuasca is an Amazonian tea containing the natural psychedelic 5-HT_2A/2C/1A agonist N,N-dimethyltryptamine (DMT). It is used in ceremonial contexts for its visionary properties. The human pharmacology of ayahuasca has been well characterized following its administration in single doses.     

Effects of low-dose <Emphasis Type="SmallCaps">d</Emphasis>-serine on recognition and working memory in mice

Rationale  

d-Serine is an endogenous co-agonist of the N-methyl-d-aspartate (NMDA) receptor and has been suggested to improve cognitive deficits in schizophrenia.     

VKORC1-3673G>A、CYP2C9*3、CYP4F2 rs2108622和CYP2C19*2基因多态性对中国汉族房颤患者华法林维持剂量的影响

目的 探讨VKORC1-3673G>A、CYP2C9^*3、CYP4F2 rs2108622和CYP2C19^*2位点基因多态性对中国汉族房颤患者华法林维持剂量的影响。方法 收集107例服用华法林达维持剂量的汉族房颤患者的血样和临床相关资料,应用PCR-RFLP法检测VKORC1-3673G>A、CYP2C9^*3、CYP4F2 rs2108622和CYP2C19^*2基因型,采用独立样本t检验分析基因型与华法林维持剂量的相关性。多元线性回归建立给药模型,探讨基因多态性对华法林维持剂量的影响。结果 VKORC1-3673G>A、CYP2C9^*3、CYP4F2 rs2108622基因多态性和患者年龄、体质量能解释45.2%的华法林维持剂量差异。CYP2C19^*2基因多态性对本研究人群华法林维持剂量无影响。结论 VKORC1-3673G>A、CYP2C9^*3、CYP4F2 rs2108622基因多态性显著影响中国汉族房颤患者的华法林维持剂量。     

Effect of naloxone and morphine on arcaine-induced state-dependent memory in rats

Rationale  

Arcaine is a competitive antagonist of the polyamine binding site at the N-methyl-D-aspartic acid receptor which induces state-dependent recall. However, no study has addressed the involvement of other neurotransmitter/neuromodulators in arcaine-induced state dependency.     

An examination of NMDA receptor contribution to conditioned responding evoked by the conditional stimulus effects of nicotine

Rationale  

Research using a drug discriminated goal-tracking (DGT) task showed that the N-methyl-d-aspartate (NMDA) channel blocker MK-801 (dizocilpine) reduced the nicotine-evoked conditioned response (CR).     

Ketamine-induced deficit of auditory gating in the hippocampus of rats is alleviated by medial septal inactivation and antipsychotic drugs

Rationale  

Gating of sensory responses is impaired in schizophrenic patients and animal models of schizophrenia. Ketamine, an N-methyl-d-aspartate receptor antagonist, is known to induce schizophrenic-like symptoms including sensory gating deficits in humans.     

A novel compound N,N-(Z)-N-(E)-tri-p-coumaroylspermidine isolated from Carthamus tinctorius L. and acting by serotonin transporter inhibition

Safflower, the dry flower of Carthamus tinctorius L., has long been applied for empirically treating cerebral ischemia and depression in traditional Chinese medicine. Pathogenesis of major depression involves monoaminergic transmission. The present study assessed whether safflower or its isolate would be effective in functionally regulating monoamine transporter using in vitro screening cell lines. We discovered that safflower insoluble fraction significantly inhibited serotonin uptake in Chinese hamster ovary cells stably expressing serotonin transporter (i.e. S6 cells). This fraction went through an activity-guided isolation and an active ingredient was obtained, which was subsequently elucidated as a novel coumaroylspermidine analog N¹,N⁵-(Z)-N¹⁰-(E)-tri-p-coumaroylspermidine using NMR techniques. Pharmacologically, this compound potently and selectively inhibited serotonin uptake in S6 cells or in synaptosomes, with IC₅₀ of 0.74 ± 0.15 µM for S6 cells or 1.07 ± 0.23 µM for synaptosomes and with a reversible competitive property for the 5HT-uptake inhibition. The potency of it for 5HT uptake was weaker than that of fluoxetine whereas efficacy generally similar for both. Animals treated with this testing compound showed a significant decrease in synaptosomal 5HT uptake capacity. Thus, N¹,N⁵-(Z)-N¹⁰-(E)-tri-p-coumaroylspermidine is a novel serotonin transporter inhibitor, which could improve neuropsychological disorders through regulating serotoninergic transmission.     

Disposition and metabolism of N,N-dimethylacetoacetamide in male F344 and Wistar-Han rats and female B6C3F1 mice

1. N,N-dimethylacetoacetamide (DMAAm) is a β-dicarbonyl compound used as an industrial intermediate. This study investigated the disposition and metabolism of [¹⁴C]DMAAm in male rats and female mice.

2. A single oral dose of [¹⁴C]DMAAm (target dose of 10 or 130?mg/kg) was administered to male F344 and Wistar-Han rats. [¹⁴C]DMAAm was almost completely absorbed and excreted in urine, with ca. 80?90% of the dose recovered within 24?h for both rat strains. Fecal excretion and CO₂ exhalation were minimal (1 and 2%, respectively). Less than 3% of the dose remained in tissues at 24?h. There was no apparent dose- or strain-related difference in the disposition of [¹⁴C]DMAAm in rats.

3. In female B6C3F1 mice administered 8?mg/kg [¹⁴C]DMAAm, 80% of the administered radioactivity was recovered in urine and cage rinse in 24?h.

4. Urinary metabolites were isolated and characterized by liquid chromatography /mass spectrometry following oral administration of 435?mg/kg [¹⁴C]DMAAm in male F344 rats. Metabolism occurred via reduction of the 3-keto group and oxidation of the N-methyl groups, to give N,N-dimethyl-3-hydroxybutanamide, N-methyl-N-hydroxymethyl-3-hydroxybutanamide, and N-hydroxymethyl-3-hydroxybutanamide, and N-demethylation to give N-monomethylacetoacetamide (MMAAm).

     

Mechanism of prostaglandin E2-, F2α- and latanoprost acid-induced relaxation of submental veins

The mechanism of prostaglandin E₂-, prostaglandin F_2α- and latanoprost acid (13,14-dihydro-17-phenyl-18,19,20-trinor-prostaglandin F_2α)-induced relaxation of the rabbit submental vein was studied. Prostaglandin E₂ caused maximum relaxation of endothelin-1 precontracted vessels (EC₅₀: 1.8×10⁻⁸ M). Much of the relaxation could be abolished by denuding the endothelium with the nitric oxide synthase inhibitor,

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-NAME (N^G-Nitro-

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-arginine methylester). CGRP-(8–37) (calcitonin gene-related peptide fragment (8–37)), a calcitonin gene-related peptide receptor antagonist, exhibited a partial blocking effect, whereas the tachykinin NK₁ receptor blocker, GR 82334 ([

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-Pro⁹[Spiro-γ-Lactam]Leu¹⁰,Trp¹¹]physalaemin (1–11)), markedly attenuated the response. Both prostaglandin F_2α and the relatively selective FP receptor agonist, latanoprost acid, caused relaxation of the veins to about 50% of the precontracted state in the presence of GR 32191B ([1R-[1α(Z),2β,3β,5α]]-(+)-7-[5-([1,1′-biphenyl]-4-ylmethoxy)-3-hydroxy-2-(1-piperidinyl)cyclopentyl]-4-heptenoic acid), a thromboxane receptor antagonist (EC₅₀: for prostaglandin F_2α 7.9×10⁻⁹ M, and for latanoprost acid 4.9×10⁻⁹ M).

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-NAME, as well as denuding the endothelium, completely abolished the effect. In addition, most or at least a large part of the relaxation was also blocked by CGRP-(8–37) as well as GR 82334. These results indicate that the FP receptor-mediated relaxation of veins is based on release of nitric oxide in addition to involvement of calcitonin gene-related peptide and substance P, or some other tachykinin, probably released from perivascular sensory nerves. The more pronounced relaxation induced by prostaglandin E₂ could be due to vasodilator EP receptors in the smooth muscle layer of the veins.     

HPMA Copolymer-Aminohexylgeldanamycin Conjugates Targeting Cell Surface Expressed GRP78 in Prostate Cancer

Purpose  

This study focused on the synthesis and in vitro characterization of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer conjugates for the delivery of geldanamycin to prostate cancer tumors. Conjugates were modified to incorporate WIFPWIQL peptide, which binds to cell-surface-expressed Glucose-regulated protein 78.