Synthesis of new 3-substituted-5-(2-hydroxyethyl)-3,4,5,6-tetrahydro-2H-l,3,5-thiadiazine-2-thione derivatives with potential antimicrobial activity

The purpose of this study is based upon design and synthesis of a new series of flexible molecules of 3,4,5,6-tetrahydro-2H-1,3,5-thiadiazine-2-thione (THTT) derivatives depending upon incorporation of 2-aminoethanol as a part of the polar moiety in this nucleus. Thirteen derivatives of 3-substituted-5-(2-hydroxyethyl)-3,4,5,6-tetrahydro-2H-1,3,5-thiadiazine-2-thione were synthesized by reaction of the appropriate alkyl, cycloalkyl, aralkyl amine, or glycine with carbon disulphide, formaldehyde, and 2-aminoethanol. The structures of the target compounds were elucidated using spectral methods as well as elemental analyses. A mass-spectrometry study was carried out on representatives of the synthesized derivatives. The title compounds were tested for their antibacterial activity in vitro against some gram positive and gram negative bacteria. The in-vitro antifungal activity was tested against dermatophytic, saprophytic, phytopathogenic, and antagonistic fungi. In most cases, the newly synthesized compounds 4-16 exhibited a considerable inhibitory effect on the growth of some of the tested organisms in comparison to that of ampicillin or muconazole as reference drugs. Moreover, the results indicated that the polar hydroxyethyl group at the N5- and the lipophilic one at the N3-positions are essential for the antimicrobial activity of the tested compounds.     

Anti‐angiogenic potential of scopoletin is associated with the inhibition of ERK1/2 activation

Angiogenesis plays an important role in many diseases, such as cancer, rheumatoid arthritis, and diabetic retinopathy. Specific inhibitors of angiogenesis are therefore expected to be potential candidate therapeutics for these disorders. Recently, several naturally occurring coumarins and synthetic analogues have proved to hinder new vessel formation. The present study was undertaken to investigate the effects of scopoletin, a phenolic coumarin compound with various biological activities on endothelial cell activation and resultant angiogenesis. Scopoletin had no cytotoxic effect on endothelial cells at the concentrations tested but suppressed the endothelial cell migration and disrupted rat tail collagen tube formation at concentrations of 62.5, 125, 250, and 500 µM, whereas it only moderately inhibited the proliferation and adhesion of endothelial cells. Notably, scopoletin (500 µM) selectively downregulated serum‐induced ERK1/2 phosphorylation, without affecting endothelial cell p38 MAPK or JNK phosphorylation. These findings demonstrate that scopoletin has anti‐angiogenic properties that are manifest mainly through inhibiting migration and tube formation of endothelial cells via downregulating ERK1/2 activation. Scopoletin may potentially be useful for the treatment of angiogenesis‐mediated diseases and could serve as a structural basis for screening for more potent synthetic analogues. Drug Dev Res 2009. © 2009 Wiley‐Liss, Inc.     

Cytolytic peptides belonging to the brevinin-1 and brevinin-2 families isolated from the skin of the Japanese brown frog, Rana dybowskii.

Peptidomic analysis of an extract of the skins of specimens of Dybowski's brown frog Rana dybowskii Gunther, 1876, collected on Tsushima Island, Japan led to the identification of 10 peptides with differential antibacterial and hemolytic activities. The primary structures of these peptides identified them as belonging to the brevinin-1 (5 peptides) and brevinin-2 (5 peptides) families of antimicrobial peptides. A peptide (FIGPIISALASLFG.NH(2)) with structural similarity to members of the temporin family was also isolated but this component lacked cytolytic activity. Phylogenetic relationships among the Japanese brown frogs (R. dybowskii, R. japonica, R. okinavana, R. ornativentris, R. pirica, R. sakuraii, R. tagoi, and R. tsushimensis) are only incompletely understood. Cladograms based upon maximum parsimony analyses of the brevinin-1 and brevinin-2 amino acid sequences provide strong support for a sister-group relationship between R. dybowskii and R. pirica and somewhat weaker support for a sister-group relationship between R. okinavana and R. tsushimensis. These conclusions are consistent with previous analyses based upon allozyme variations and comparisons of the nucleotide sequences of mitochondrial genes.     

Synthesis andin vitro evaluation of some novel benzofuran derivatives as potential anti-HIV-1, anticancer, and antimicrobial agents

A novel series of 1-(1-benzofuran-2-yl-ethylidene)-4-substituted thiosemicarbazides (2a-d) along with some derived ring systems: substituted-2,3-dihydro-thiazoles (3a-c, 4a-f) and thiazolidin-4-ones (5a-d and 6a-d), were synthesized. In addition, cyanoacetic acid-(1-benzofuran-2-yl-ethylidene) hydrazide (7) was used to prepare another new series of compounds consisting of substituted pyridin-2(1H)-ones (8a-c); 2-thioxo-2,3-dihydro-thiazoles (9a-d) and 2-thioxo-2,3-dihydro-6H-thiazolo[4,5-d]pyrimidin-7-ones (10a-c, 11a-c). The absolute configuration of compound 5c was determined by X-ray crystallography. The compounds prepared were evaluated for their in vitro anti-HIV, anticancer, antibacterial, and antifungal activities. Among the tested compounds, compounds 5c and 9a produced a significant reduction [symbols, see text] the viral cytopathic effect (93.19% and 59.55%) at concentrations > 2.0 x 10(-4) M and 2.5 x 10(-5) M respectively. Compound 9a was confirmed to have moderate anti-HIV activity. Compounds 2a, 2d, and 5c showed mild antifungal activity. However, none of the tested compounds showed any significant anticancer activity.     

Pharmacokinetic changes of M1, M2, M3 and M4 after intravenous administration of a new anthracycline,DA-125, to rats pretreated with phenobarbital, 3-methylcholanthrene,chloramphenicol, or SKF-525A

The pharmacokinetics of M1–M4, the metabolites of a new anthracycline antineoplastic agent, DA-125, were compared after intravenous (IV) administration of DA-125, 15 mg kg⁻¹, to rats pretreated with enzyme inducers, such as phenobarbital (PBT, n = 14) and 3-methylcholanthrene (MCT, n = 15), or enzyme inhibitors, such as SKF-525A (SKT, n = 11) and chloramphenicol (CMT, n = 15), and to their control rats (n = 15 for PBC, CMC or SKC, and n = 11 for MCC). After IV administration of DA-125, the plasma concentrations of both M1 and M2 declined slowly from 1 to 2 h onwards to 8 h in all groups of rats due to the continuous formation of M2 from M1. The AUC_{0–8 h} of M1 (47.1 versus 7.85 μg min mL⁻¹) and M2 (20.7 versus 44.3 μg min mL⁻¹) decreased significantly in the PBT group compared to those in the PBC group. However, the corresponding value of only M1 (74.6 versus 89.9 μg min mL⁻¹) decreased significantly in the MCT group. The above data indicate that metabolism of M1 is increased by pretreatment with both PB and 3-MC, and that of M2 with PB, but not with 3-MC. The AUC_{0–8 h} of both M1 (126 versus 78.5 μg min mL⁻¹) and M2 (69.2 versus 44.3 μg min mL⁻¹) increased significantly in the SKT group compared to the SKC group. However, the corresponding values were not significantly different between CMC and CMT groups. The above data indicate that the metabolism of both M1 and M2 is inhibited by pretreatment with SKF-525A, but not with CM. © 1998 John Wiley & Sons, Ltd.     

Pharmacokinetics of liquiritigenin and its two glucuronides,M1 and M2, in rats with acute hepatitis induced by d-galactosamine/lipopolysaccharide or CCl4

1. Cytoprotective effects of liquiritigenin (LQ) against liver injuries have been reported, but its pharmacokinetics has not been studied in acute hepatitis. Thus, pharmacokinetics of LQ and its two conjugated glucuronide metabolites: 4′-O-glucuronide (M1) and 7-O-glucuronide (M2), in rats with acute hepatitis induced by d-galactosamine/lipopolysaccharide (GalN/LPS) rats or carbon tetrachloride-treated (CCl₄-treated) rats were evaluated.

2. LQ was administered intravenously (20?mg kg^?1) and orally (50?mg kg^?1) to control GalN/LPS and CCl₄-treated rats. Expression of uridine 5′-diphospho-glucuronosyltransferases 1A (UGT1A) and in vitro metabolism of LQ in hepatic and intestinal microsomes were also measured.

3. After intravenous administration of LQ, area under the plasma concentration-time curve (AUC) of LQ in GalN/LPS rats was significantly smaller than that in controls due to faster non-renal clearance, as a result of its greater free fraction in plasma and faster hepatic blood flow rate than the controls. In CCl₄-treated rats, the AUC_{M1, 0?8 h}/AUC_LQ and AUC_{M2, 0?8 h}/AUC_LQ ratios were significantly greater than the controls due to decrease in biliary excretion of M1 and M2. However, no significant pharmacokinetic changes were observed in both acute hepatitis rats after oral administration due to comparable intestinal metabolism of LQ.

4. Modification of oral dosage regimen of LQ may not be necessary in patients with acute hepatitis; but human studies are required.

     

Synthesis of highly potent lymphocyte function‐associated antigen‐1 antagonists labeled with carbon‐14 and with stable isotopes,part 3

The drug candidates ( 2 ) and ( 3 ) are highly potent LFA‐1 inhibitors. They were efficiently prepared labeled with carbon‐14 using a palladium‐catalyzed carboxylation of an iodo‐precursor ( 5 ) and sodium formate‐¹⁴C to afford acid [¹⁴C]‐( 6 ), which was coupled via an amide bond to chiral amines ( 7 ) and ( 8 ) in 52% and 48% overall yield, respectively, and with specific activities higher than 56 mCi/mmol and radiochemical purities of 99%. For stable isotopes synthesis, the amine [²H₈]‐( 7 ) was synthesized in three steps from 2‐cyanopyridine‐²H₄ using Kulinkovich‐Szymonik aminocyclopropanation, followed by coupling to L ‐alanine‐2,3,3,3‐²H₄‐N‐t‐BOC, and then removal of the BOC‐protecting group. Amide bond formation with acid ( 6 ) gave [²H₈]‐( 2 ) in 36% overall yield. The amine [¹³C₄,¹⁵N]‐( 8 ) was obtained in two steps using L‐threonine‐¹⁴C₄,¹⁵N and then coupled to acid [¹³C]‐( 6 ) to give [¹³C₅,¹⁵N]‐( 3 ) in 56% overall yield.     

Synthesis, physicochemical properties and biological evaluation of aromatic ester prodrugs of 1-(2'-hydroxyethyl)-2-ethyl-3-hydroxypyridin-4-one (CP102): orally active iron chelators with clinical potential.

The synthesis of seven aromatic ester derivatives of 1-(2'-hydroxyethyl)-2-ethyl-3-hydroxypyridin-4-one is described. These ester prodrugs have been designed to target iron chelators to the liver, the major iron storage organ. In principle this should improve chelation efficacy and minimize toxicity. The distribution coefficients of these ester prodrugs between 1-octanol and MOPS buffer pH 7.4 were measured together with their rates of hydrolysis at pH 2 and pH 7.4, in rat blood and liver homogenate. Esters with heteroaromatic acid moieties were found to be less stable than benzoyl analogues. The in-vivo iron mobilisation efficacy of these ester prodrugs has been compared with that of the parent drug using a 59Fe-ferritin loaded rat model. Many prodrugs were found to enhance the ability of the parent hydroxypyridinone to facilitate 59Fe excretion. However, not all prodrugs provided increased efficacy, demonstrating that lipophilicity is not the only factor which influences drug efficacy. Furthermore, no clear correlation between efficacy and susceptibility to hydrolysis was detected. The picolinic and nicotinic ester derivatives appear to offer the best potential as prodrugs as they have a relatively low LogP value and yet lead to enhanced efficacy over the parent hydroxypyridinone.     

Growth inhibitory effect of β‐eudesmol on cholangiocarcinoma cells and its potential suppressive effect on heme oxygenase‐1 production,STAT1/3 activation,and NF‐κB downregulation

Cholangiocarcinoma (CCA) is a progressively fatal form of cancer originating from the malignant transformation of hepatic biliary cholangiocytes. The present study reports for the first time in vitro growth inhibitory activities of β‐eudesmol, the bioactive sesquiterpenoid present in the rhizome of Atractylodes lancea (Thunb) DC., with respect to its underlying potential effects on heme oxygenase‐1 (HO‐1) production, STAT1/3 phosphorylation, and NF‐κB protein expression in human CCA cell line CL‐6. The cytotoxic effect of β‐eudesmol on CL‐6 cells was evaluated by MTT assay using normal human embryonic fibroblast (OUMS) as a control cell line. Results indicated that β‐eudesmol exhibited selective cytotoxicity towards CL‐6 compared to OUMS with mean (±SD) IC₅₀ (concentration that inhibits cell growth by 50%) values of 166.75 ± 3.69 and 240.01 ± 16.54 μmol/L, respectively. In addition, it also significantly suppressed colony forming and wound healing ability of CL‐6 cells in a concentration‐dependent manner. Western blot analysis indicated that β‐eudesmol treatment resulted in significant suppression of HO‐1 production in CL‐6 cells. Its inhibitory effects on the phosphorylation of STAT1/3 proteins and expression of NF‐κB (p65 and p50) proteins were concentration‐dependent. Taken together, these results suggest that β‐eudesmol exerts significant growth inhibitory activity on CL‐6 cells that may be linked to its inhibitory effect on the production of HO‐1, phosphorylation of STAT1/3, and expression of major NF‐κB proteins.     

Role of MAP kinases in regulating expression of antioxidants and inflammatory mediators in mouse keratinocytes following exposure to the half mustard, 2-chloroethyl ethyl sulfide

Dermal exposure to sulfur mustard causes inflammation and tissue injury. This is associated with changes in expression of antioxidants and eicosanoids which contribute to oxidative stress and toxicity. In the present studies we analyzed mechanisms regulating expression of these mediators using an in vitro skin construct model in which mouse keratinocytes were grown at an air-liquid interface and exposed directly to 2-chloroethyl ethyl sulfide (CEES), a model sulfur mustard vesicant. CEES (100-1000 µM) was found to cause marked increases in keratinocyte protein carbonyls, a marker of oxidative stress. This was correlated with increases in expression of Cu,Zn superoxide dismutase, catalase, thioredoxin reductase and the glutathione S-transferases, GSTA1-2, GSTP1 and mGST2. CEES also upregulated several enzymes important in the synthesis of prostaglandins and leukotrienes including cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-2 (mPGES-2), prostaglandin D synthase (PGDS), 5-lipoxygenase (5-LOX), leukotriene A₄ (LTA₄) hydrolase and leukotriene C₄ (LTC₄) synthase. CEES readily activated keratinocyte JNK and p38 MAP kinases, signaling pathways which are known to regulate expression of antioxidants, as well as prostaglandin and leukotriene synthases. Inhibition of p38 MAP kinase suppressed CEES-induced expression of GSTA1-2, COX-2, mPGES-2, PGDS, 5-LOX, LTA₄ hydrolase and LTC₄ synthase, while JNK inhibition blocked PGDS and GSTP1. These data indicate that CEES modulates expression of antioxidants and enzymes producing inflammatory mediators by distinct mechanisms. Increases in antioxidants may be an adaptive process to limit tissue damage. Inhibiting the capacity of keratinocytes to generate eicosanoids may be important in limiting inflammation and protecting the skin from vesicant-induced oxidative stress and injury.     

三氯乙烯对3种细胞色素P450酶基因表达的影响

目的 探讨三氯乙烯（Trichloroethylene,TCE)对人体淋巴细胞瘤细胞株（MCL-5）中3种细胞色素P450酶基因（CYP1A1、CYP2E1、CYP3A4）表达的影响,并研究剂量反应关系和时间反应关系,方法 用常规的细胞培养方法,0.5、1.0、1.5、2.0mmol/L TCE处理细胞12、24、48、72h。利用提纯RNA和cDNA的药盒,合成cDNA,然后逆转录聚合酶反应（RT-PCR）表达3种CYP450基因,以β-Actin作为内对照,分析不同处理剂量和时间时基因表达的强度。结果 在MCL-5细胞株中都有基本的表达,CYP1A1表达在用1.0、1.5、2.0mmol/LTCE处理48h后有被上调的趋势,而且上调趋势随处理时间延长耐加强;CYP2E1、CYP3A4表达不受TCE处理时间长短的影响。3种CYP450酶基因的表达受TCE剂量的影响。3随0.5mol/L,1.0、1.5、2.0mmol/L剂量的增加有上调的趋势,结论 TCE对CYP450酶系统中的CYP2E1、CYP1A1、CYP3A4基因有明显的诱导作用。这些基因被诱导后的结果。可能会导致相对应酶活性的增加,同时加强对TCE的代谢,使TCE的代谢产物增加。     

Contribution of CYP2C9, CYP2A6, and CYP2B6 to valproic acid metabolism in hepatic microsomes from individuals with the CYP2C9*1/*1 genotype.

The present study investigated the role of specific human cytochrome P450 (CYP) enzymes in the in vitro metabolism of valproic acid (VPA) by a complementary approach that used individual cDNA-expressed CYP enzymes, chemical inhibitors of specific CYP enzymes, CYP-specific inhibitory monoclonal antibodies (MAbs), individual human hepatic microsomes, and correlational analysis. cDNA-expressed CYP2C9*1, CYP2A6, and CYP2B6 were the most active catalysts of 4-ene-VPA, 4-OH-VPA, and 5-OH-VPA formation. The extent of 4-OH-VPA and 5-OH-VPA formation by CYP1A1, CYP1A2, CYP1B1, CYP2C8, CYP2C19, CYP2D6, CYP2E1, CYP4A11, CYP4F2, CYP4F3A, and CYP4F3B was only 1-8% of the levels by CYP2C9*1. CYP2A6 was the most active in catalyzing VPA 3-hydroxylation, whereas CYP1A1, CYP2B6, CYP4F2, and CYP4F3B were less active. Correlational analyses of VPA metabolism with CYP enzyme-selective activities suggested a potential role for hepatic microsomal CYP2A6 and CYP2C9. Chemical inhibition experiments with coumarin (CYP2A6 inhibitor), triethylenethiophosphoramide (CYP2B6 inhibitor), and sulfaphenazole (CYP2C9 inhibitor) and immunoinhibition experiments (including combinatorial analysis) with MAb-2A6, MAb-2B6, and MAb-2C9 indicated that the CYP2C9 inhibitors reduced the formation of 4-ene-VPA, 4-OH-VPA, and 5-OH-VPA by 75-80% in a panel of hepatic microsomes from donors with the CYP2C9*1/*1 genotype, whereas the CYP2A6 and CYP2B6 inhibitors had a small effect. Only the CYP2A6 inhibitors reduced VPA 3-hydroxylation (by approximately 50%). The extent of inhibition correlated with the catalytic capacity of these enzymes in each microsome sample. Overall, our novel findings indicate that in human hepatic microsomes, CYP2C9*1 is the predominant catalyst in the formation of 4-ene-VPA, 4-OH-VPA, and 5-OH-VPA, whereas CYP2A6 contributes partially to 3-OH-VPA formation.     

Sodium selenite-induced apoptosis in murine B-lymphoma cells is associated with inhibition of protein kinase C-delta, nuclear factor kappaB, and inhibitor of apoptosis protein.

Selenium (Se) is an essential trace element possessing anticarcinogenic properties and other biological functions. This study determined the role sodium selenite plays on intracellular signaling, including protein kinase C (PKC), nuclear factor-kappa B (NF-kappaB), and inhibitor of apoptosis protein (IAP) in murine B lymphoma (A20) cells. In vitro supplementation of A20 cells with low concentrations of sodium selenite (0.005-5 microM) caused a significant increase in cellular proliferation exclusively at 72 h. Proliferation and cell viability were decreased in response to selenium concentrations of >/= 25 microM and >/= 5 microM at 72 and 96 h, respectively. Flow cytometric analysis of A20 cells exposed to 5 microM Se at 72 and 96 h indicated G(2)-M phase arrest and increased cell death at higher concentrations. Se-induced cytotoxicity was associated with apoptosis indicated by nuclear fragmentation and DNA laddering. Se concentrations, which induced cell cycle arrest and apoptosis, were associated with inhibition of cytosol to membrane translocation of PKCdelta and PKC activity at 72 h. Coincubation of cultures with 0.5 microM phorbol 12-myristate 13-acetate (PMA) and Se (5 and 25 microM) reversed the Se-induced cell death at 72 h. The nuclear NF-kappaB translocation and NF-kappaB DNA-binding were inhibited by increasing concentrations of Se (5 and 25 microM) at 72 h. After 72 h exposure to 5 and 25 microM Se, cIAP-2 concentration was decreased. Differential inhibition of PKCdelta, NF-kappaB, and cIAP-2 by Se may represent important intracellular signaling processes through which Se induces apoptosis and subsequently exerts its anticarcinogenic potential.     

Serum MMP-8, -9 and TIMP-1 in sepsis: High serum levels of MMP-8 and TIMP-1 are associated with fatal outcome in a multicentre, prospective cohort study. Hypothetical impact of tetracyclines

Recent evidence suggests that matrix metalloproteinases (MMPs) and their endogenous inhibitors are involved in the pathogenesis of sepsis. We studied serum levels of MMP-8, MMP-9 and TIMP-1 (tissue inhibitor of matrix metalloproteinase-1) in a multicentre, prospective cohort study of patients with sepsis treated in Intensive Care Units (ICUs). We analyzed serum samples taken on ICU admission from 248 critically ill sepsis patients. MMP-8, -9 and TIMP-1 serum levels were analyzed by enzyme-linked immunosorbent assays. Serum MMP-8, MMP-9 and TIMP-1 levels were significantly higher in patients with severe sepsis than in healthy controls. Serum MMP-8 levels among non-survivors (n = 33) were significantly (p = 0.006) higher than among survivors (n = 215). Serum TIMP-1 but not MMP-9 levels were significantly higher among non-survivors than survivors (p < 0.0001, p = 0.079, respectively). Systemic MMP-8 is upregulated in sepsis suggesting that MMP-8 may contribute to the host response during sepsis. High serum MMP-8 and TIMP-1 levels at ICU admission were seen among patients with fatal outcome. With this background, clinical studies examining the ability of MMP-inhibitors (such as the non-antimicrobial properties of tetracyclines) to diminish the MMP-mediated inflammatory response are needed to develop novel therapies in order to improve the outcome of sepsis.     

F15063, a potential antipsychotic with dopamine D(2)/D(3) antagonist, 5-HT(1A) agonist and D(4) partial agonist properties: (IV) duration of brain D2-like receptor occupancy and antipsychotic-like activity versus plasma concentration in mice

F15063 (N-[(2,2-dimethyl-2,3-dihydro-benzofuran-7-yloxy)ethyl]-3-(cyclopent-1-enyl)-benzylamine fumarate salt) is a novel potential antipsychotic with dopamine D₂/D₃ blocking properties and agonist activity at 5-HT_1A and D₄ receptors. The pertinent parameter for pharmacological activity of antipsychotics appears to be central D2-like receptor occupancy. However, its duration is not necessarily correlated with drug plasma levels, on which clinical dosing regimens are often based. Thus, we compared in mice the duration of actions of F15063 and haloperidol to (1) inhibit apomorphine-induced climbing and sniffing (behavioural measures of D2-like receptor antagonism) and (2) occupy D2-like receptors in vivo in the striatum and olfactory tubercles (inhibition of [³H]nemonapride binding). Finally, we measured plasma levels of F15063. D2-like receptor occupancy in the striatum remained elevated at 1, 4 and 8 h postadministration, with both F15063 (ID₅₀: 7.1, 3.6 and 16.5 mg/kg p.o., respectively) and the typical antipsychotic, haloperidol (ID₅₀: 1.4, 0.52 and 0.53 mg/kg p.o., respectively). This was paralleled by a protracted inhibition of apomorphine-induced climbing (ED₅₀: 0.9, 2.8 and 3.6 mg/kg p.o., and 0.21, 0.37 and 0.87 mg/kg p.o., respectively, for F15063 and haloperidol). In contrast, after administration of 10 mg/kg p.o. of F15063, its plasma levels decreased rapidly: 15.2, 2.1 and 0.6 ng/ml, 1, 4 and 8 h after administration, respectively. A similar pattern of results was observed when F15063 and haloperidol were administered i.p. and s.c., respectively. To summarise, the time-course of D2-like receptor occupancy and inhibition of apomorphine-climbing (and sniffing) behaviours was similarly long lasting with F15063 and haloperidol. In addition, the durations of action of F15063 and haloperidol in a behavioural model of antipsychotic-like activity were closely correlated to their occupancy of central D2-like receptors, and much longer than their presence in plasma.     

Design,syntheses, and evaluation of 2,3‐diphenylcycloprop‐2‐en‐1‐ones and oxime derivatives as potential cyclooxygenase‐2 (COX‐2) inhibitors with analgesic‐antiinflammatory activity

A group of 2,3‐diphenylcycloprop‐2‐enes having a variety of substituents at the para‐position of the C‐2 phenyl ring (H, F), and C‐3 phenyl ring (H, F, SMe, SOMe, SO₂Me), in conjunction with either a C‐1 carbonyl, oxime, oxime acetate, benzoyl hydrazone, or hydrogen substituent were synthesized for in vivo evaluation as analgesic and antiinflammatory (AI) agents, and as potential selective cyclooxygenase‐2 (COX‐2) inhibitors. This group of cycloprop‐2‐ene compounds exhibited significant analgesic activity, since 4% NaCl‐induced abdominal constriction was reduced by 43–90% at 30 min, and 41–100% at 60 min, after drug administration relative to the reference drugs aspirin and celecoxib (58% and 32% inhibition at 30 min after drug administration) for a 50 mg/kg intraperitoneal dose. AI activities, determined using the carrageenan‐induced rat paw edema assay, showed that this class of cycloprop‐2‐ene compounds exhibited AI activities in the inactive‐to‐modest activity range (0–26% inhibition) for a 50 mg/kg oral dose. The AI potency order for a group of 2,3‐diphenylcycloprop‐2‐enes with respect to the C‐1 substituent was oxime>hydrogen>carbonyl>benzoyl hydrazone. 2,3‐Diphenylcycloprop‐2‐en‐1‐one oxime ( 20 ) was the most active AI agent, inducing a 26% reduction in inflammation, relative to the reference drugs ibuprofen and celecoxib, which showed 52% and 58% reductions in inflammation, at 5 h after drug administration. In vitro COX‐1 and COX‐2 inhibition studies showed that 2,3‐diphenylcycloprop‐2‐en‐1‐one oxime ( 20 ) is a selective COX‐2 inhibitor (COX‐1 IC₅₀>100 μM; COX‐2 IC₅₀=2.94 μM; COX‐2 selectivity index>34). A molecular modeling study that docked the oxime ( 20 ) in the active site of the human COX‐2 isozyme showed that it binds in the vicinity of the mouth of the COX‐2 binding site with the O‐atom of the oxime (=N–OH) moiety separated from the NH₂ group of Arg¹²⁰ by about 3.65 Å. This orientation of the oxime compound ( 20 ) in the COX‐2 binding site could be due to a potentially strong ionic interaction between the =NOH oxime moiety and the guanidinium moiety of Arg¹²⁰. Drug Dev. Res. 57:6–17, 2002. © 2002 Wiley‐Liss, Inc.     

Amlodipine alleviates cisplatin-induced nephrotoxicity in rats through gamma-glutamyl transpeptidase (GGT) enzyme inhibition,associated with regulation of Nrf2/HO-1, MAPK/NF-κB,and Bax/Bcl-2 signaling

BackgroundThe therapeutic utility of the effective chemotherapeutic agent cisplatin is hampered by its nephrotoxic effect. We aimed from the current study to examine the possible protective effects of amlodipine through gamma-glutamyl transpeptidase (GGT) enzyme inhibition against cisplatin nephrotoxicity.MethodsAmlodipine (5 mg/kg, po) was administered to rats for 14 successive days. On the 10^th day, nephrotoxicity was induced by a single dose of cisplatin (6.5 mg/kg, ip). On the last day, blood samples were collected for estimation of kidney function, while kidney samples were used for determination of GGT activity, oxidative stress, inflammatory, and apoptotic markers, along with histopathological evaluation.ResultsAmlodipine alleviated renal injury that was manifested by significantly diminished serum creatinine and blood urea nitrogen levels, compared to cisplatin group. Amlodipine inhibited GGT enzyme, which participates in the metabolism of extracellular glutathione (GSH) and platinum-GSH-conjugates to a reactive toxic thiol. Besides, amlodipine diminished mRNA expression of NADPH oxidase in the kidney, while enhanced the anti-oxidant defense by activating Nrf2/HO-1 signaling. Additionally, it showed marked anti-inflammatory response by reducing expressions of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB), with subsequent down-regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Moreover, amlodipine reduced Bax/Bcl-2 ratio and elevated hepatocyte growth factor (HGF), thus favoring renal cell survival.ConclusionsEffective GGT inhibition by amlodipine associated with enhancement of anti-oxidant defense and suppression of inflammatory signaling and apoptosis support our suggestion that amlodipine could replace toxic GGT inhibitors in protection against cisplatin nephrotoxicity.