Synthesis,characterization and antitumor studies of transition metal complexes of o-hydroxydithiobenzoate

o-Hydroxydithiobenzoate (o-HOdtb) forms complexes, [Ni(o-HOdtb)(o-HOdtbS)], [Cu(o-Odtb)], [Co(o-HOdtb)(3)], [Fe(2)(o-Odtb)(3)], [Bu(n)(4)N][V(o-Odtb)(3)] and [Bu(n)(4)N][Zn(o-HOdtb)(3)] which were characterized by analyses and physicochemical studies. The bonding sites of o-HOdtb and the geometry of the complexes were determined by magnetic susceptibility, IR, ESR, NMR, M?ssbauer and electronic spectral data. The structure of [Bu(n)(4)N][Zn(o-HOdtb)(3)] and H(2)C(o-HOdtb)(2) were assigned by single crystal X-ray diffraction studies. The monomeric complex [Bu(n)(4)N][Zn(o-HOdtb)(3)] crystallizes in Pna2(1) space group. The M?ssbauer spectra of [Fe(2)(o-Odtb)(3)] at 298 and 80K suggest the presence of high spin iron(III) with an S=5/2 state. All the metal complexes were observed to inhibit the growth of tumor in vitro, whereas, ligand did not. In vivo administration of these complexes resulted in prolongation of survival of tumor-bearing mice. Tumor bearing mice administered with metal complexes showed reversal of tumor growth associated induction of apoptosis in lymphocytes. The paper discusses the possible mechanisms and therapeutic implication of the ligand and its metal complexes in tumor regression and tumor growth associated immunosuppression.     

Layer-by-layer self-assembly of functionalized graphene nanoplates for glucose sensing in vivo integrated with on-line microdialysis system

In this work, a novel amperometric biosensor for hydrogen peroxide was fabricated through the layer-by-layer (LBL) self-assembling of amine-terminated ionic liquid (IL-NH(2)), and sulfonic acid (SO(3)(-)) functionalized graphene by covalent bonding. The modification of the two functionalities introduced positive and negative charge onto the surface of graphene respectively, thus facilitating the formation of a multilayer film denoted with {IL-RGO/S-RGO}(n) through electrostatic interaction and further immobilization of glucose oxidase (GOx). The resulting {IL-RGO/S-RGO}(n)/GOx/Nafion biosensor displayed an excellent response to glucose at a potential of -200 mV. Combined with on-line microdialysis system, the glucose biosensor in the on-line system showed good linear range from 10 μM to 500 μM with the detection limit of 3.33 μM (S/N=3). Consequently, the basal level of glucose in the striatum of anesthetic rats was calculated to be 0.376 ± 0.028 mM (mean ± s.d., n=3). The {IL-RGO/S-RGO}(n)/GOx/Nafion biosensor was further applied for in vivo sensing of the glucose level in the striatum when rats received intraperitoneal (i.p.) injection of 30 μL insulin, which resulted in an obvious decrease in the extracellular concentration of glucose within 30 min. The method was proved to be sensitive and reproducible, which enabled its promising application in physiology and pathology.     

Performance of D-amino acid oxidase in presence of ionic liquids

The activity and stability of free and immobilized D-amino acid oxidase (DAAO, EC 1.4.3.3) from Trigonopsis variabilis CBS 4095 in different water-soluble and water-insoluble ionic liquids (ILs) as well as in organic solvents were studied for comparison. The most promising ILs ([BMIM][BF(4)] and [MMIM][MMPO(4)]) were investigated in detail. The kinetic parameters (v(max) = 187 nkat/g dry weight, K(M) = 1.38 mM) with D-phenylalanine as substrate were calculated in 40% [BMIM][BF(4)]. Bioconversions of D/L-phenylalanine in 40% [BMIM][BF(4)] and 20% [MMIM][MMPO(4)] on a 3 ml scale using immobilized DAAO were performed by addition of free catalase from Micrococcus lysodeikticus. After total conversion of substrate in presence of 20% [MMIM][MMPO(4)] the residual activity of the immobilized DAAO was 79% and 100% of the free catalase.     

One-pot regioselective synthesis of tetrahydroindazolones and evaluation of their antiproliferative and Src kinase inhibitory activities

A number of 2-substituted tetrahydroindazolones were synthesized by three-component condensation reaction of 1,3-diketones, substituted hydrazines, benzaldehydes, and Yb(OTf)(3) as a catalyst in [bmim][BF(4)] ionic liquid using a simple, efficient, and economical one-pot method. The synthesized tetrahydroindazolones were evaluated for inhibition of cell proliferation of human colon carcinoma (HT-29), human ovarian adenocarcinoma (SK-OV-3), and c-Src kinase activity. 3,4-Dichlorophenyl tetrahydroindazolone derivative (15) inhibited the cell proliferation of HT-29 and SK-OV-3 cells by 62% and 58%, respectively. 2,3-Diphenylsubstituted tetrahydroindazolone derivatives, inhibited the cell proliferation of HT-29 cells by 65-72% at a concentration of 50 μM. In general, the tetrahydroindazolones showed modest inhibition of c-Src kinase where 4-tertbutylphenyl- and 3,4-dichlorophenyl- derivatives showed the inhibition of c-Src kinase with IC(50) values of 35.1 and 50.7 μM, respectively.     

A paradoxical method for NAD(+)/NADH accumulation on an electrode surface using a hydrophobic ionic liquid

In this communication, we describe a novel and facile method for the immobilization of NAD(+)/NADH on an electrode surface using a hydrophobic ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][Tf(2)N]). By taking advantage of the insolubility of NAD(+)/NADH in hydrophobic ionic liquids, it is expected that NAD(+)/NADH can be retained on the electrode's surface. Alcohol dehydrogenase (ADH) and NAD(+)/NADH were immobilized with a gelatin hydrogel on an electrode that was modified with an electropolymerized ruthenium complex containing 5-amino-1,10-phenanthroline (pAPRu) as a mediator for NADH oxidation. The (ADH, NAD(+))/pAPRu-immobilized electrode exhibited the electrocatalytic oxidation of ethanol in [C4mim][Tf(2)N]. The obtained catalytic current in [C4mim][Tf(2)N] was comparable to that in buffer solution containing NAD(+). It was confirmed by UV-vis spectroscopy that NAD(+) did not dissolve in the [C4mim][Tf(2)N] and was retained on the electrode's surface. Furthermore, we succeeded in constructing an ethanol/O(2) biofuel cell comprised of an (ADH, NAD(+))/pAPRu anode and a bilirubin oxidase cathode using [C4mim][Tf(2)N] as an electrolyte.     

Synthesis, structure and luminescence studies of heterometallic gold(I)-copper(I) and -silver(I) alkynyl clusters/aggregates.

A series of pentanuclear gold(I)-copper(I) and -silver(I) mixed-metal alkynyl complexes, [(n)Bu(4)N][Au(3)M(2)(C triple bond CC(6)H(4)R-p)(6)] [M = Cu, R = OMe, O(n)Bu, O(n)Hex, Me, Et; M = Ag, R = Et, O(n)Hex] have been synthesized. The complexes were found to be emissive both in the solid state and in fluid solutions. DFT calculations at the B3LYP level of theory were performed on [Au(3)M(2)(C triple bond CC(6)H(4)Me-p)(6)](-) (M = Cu, Ag) to provide an understanding on the electronic structure of the complexes.     

Thermophilic enrichment of microbial communities in the presence of the ionic liquid 1‐ethyl‐3‐methylimidazolium acetate

Aims

The aim of the study was to develop an approach to enrich ionic liquid tolerant micro‐organisms that efficiently decompose lignocellulose in a thermophilic and high‐solids environment.

Methods and Results

High‐solids incubations were conducted, using compost as an inoculum source, to enrich for thermophilic communities that decompose switchgrass in the presence of the ionic liquid 1‐ethyl‐3‐methylimidazolium acetate ([C2mim][OAc]). Ionic liquid levels were increased from 0 to 6% on a total weight basis incrementally. Successful enrichment of a community that decomposed lignocellulose at 55°C in the presence of 6% [C2mim][OAc] was achieved, when the [C2mim][OAc] level was increased stepwise from 2% to 4% to 5% to 6%. Pyrosequencing results revealed a shift in the community and a sharp decrease in richness, when thermophilic conditions were applied.

Conclusions

A community tolerant to a thermophilic, high‐solids environment containing 6% [C2mim][OAc] was enriched from compost. Gradually increasing [C2mim][OAc] concentrations allowed the community to adapt to [C2mim][OAc].

Significance and Impact of the Study

A successful approach to enrich communities that decompose lignocellulose under thermophilic high‐solids conditions in the presence of elevated levels of [C2mim][OAc] has been developed. Communities yielded from this approach will provide resources for the discovery of enzymes and metabolic pathways relevant to biomass pretreatment and fuel production.     

Delivery of floxuridine derivatives to cancer cells by water-soluble organometallic cages

The self-assembly of 2,4,6-tris(pyridin-4-yl)-1,3,5-triazine (tpt) triangular panels with p-cymene (pPr(i)C(6)H(4)Me) ruthenium building blocks and 2,5-dioxydo-1,4-benzoquinonato (dobq) or 5,8-dioxydo-1,4-naphthoquinonato (donq) bridges, in the presence of a pyrenyl-nucleoside derivatives (pyreneR), affords the triangular prismatic host-guest compounds [(pyrene-R)?Ru(6)(pPr(i)C(6)H(4)Me)(6)(tpt)(2)(dobq)(3)](6+) ([(pyrene-R)?1](6+)) and [(pyrene-R)?Ru(6)(pPr(i)C(6)H(4)Me)(6)(tpt)(2)(donq)(3)](6+) ([(pyrene-R)?2](6+)), respectively. The inclusion of six monosubstitutedpyrenyl-nucleosides (pyrene-R1 = 5'-(1-pyrenyl butanoate)-2'-deoxyuridine, pyrene-R2 = 5-fluoro-5'-(1-pyrenyl butanoate)-2'-deoxyuridine, pyrene-R3 = 5'-{N-[1-oxo-4-(1-pyrenyl)butyl]-glycyl}-2'-deoxyuridine, pyrene-R4 = 5-fluoro-5'-{N-[1-oxo-4-(1-pyrenyl)butyl]-glycyl}-2'-deoxyuridine, pyrene-R5 = 5-fluoro-5'-{N-[1-oxo-4-(1-pyrenyl)butyl]-phenylalanyl}-2'-deoxyvuridine, pyrene-R6 = 5-fluoro-5'-{N-[1-oxo-4-(1-pyrenyl)butyl]-phenylalanyl}-2'-deoxyuridine) has been accomplished. The carceplex nature of [(pyrene-R)?1](6+) with the pyrenyl moiety firmly encapsulated in the hydrophobic cavity of the cage with the nucleoside groups pointing outward was confirmed by NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS), while the host-guest nature of [(pyrene-R)?2](6+) was studied in solution by NMR techniques. In contrast to the floxuridine compounds used in the clinic, the host-guest complexes are highly water-soluble. Consequently, the cytotoxicities of these water-soluble compounds have been established using human ovarian A2780 and A2780cisR cancer cells. All the host-guest systems are more cytotoxic than the empty cages alone [1][CF(3)SO(3)](6) (IC(50) = 23 μM) and [2][CF(3)SO(3)](6) (IC(50) = 10 μM), the most active compound [pyrene-R4?1][CF(3)SO(3)](6)being 2 orders of magnitude more cytotoxic (IC(50) = 0.3 μM) on these human ovarian cancer cell lines (A2780 and A2780cisR).     

Feruloyl esterase-catalysed synthesis of glycerol sinapate using ionic liquids mixtures

The ability of a feruloyl esterase (AnFaeA), either in free or immobilised (cross-linked enzyme aggregates) form, to catalyse the esterification of glycerol, a major by-product of the biodiesel industry, with sinapic acid was studied in four hexafluorophosphate anion-containing ionic liquids: ([Bmim][PF(6)], [Omim][PF(6)], [C(2)OHmim][PF(6)] and [C(5)O(2)mim][PF(6)]). Such ionic liquids are considered 'green' reaction systems. The synthetic reaction was optimised in [C(2)OHmim][PF(6)] and the highest conversion yield was 72.5+/-2.1%, while, at the same reaction conditions in [C(5)O(2)mim] [PF(6)], a similar conversion yield was obtained (76.7+/-1.5%). AnFaeA was active in its free and immobilised form, with the latter retaining a part of its synthetic activity after 5 consecutive 24h-period reaction cycles. Sinapic acid was esterified to one of the primary hydroxyl groups of glycerol and retained, after esterification, 63.1+/-0.3% and 89.5+/-1.1% of its antioxidant activity against low-density lipoprotein oxidation, when added at concentrations of 10 and 60muM, respectively, in the assay mixture.     

Silicic acid (Si(OH)(4)) is a significant influence upon the atomic absorption signal of aluminium measured by graphite furnace atomic absorption spectrometry (GFAAS).

We have identified silicic acid (Si(OH)(4)) as an important modifier of the absorbance signal of aluminium measured by graphite furnace atomic absorption spectrometry (GFAAS). The presence of Si(OH)(4) enhanced the signal by as much as 50%. The extent of the enhancement was dependent upon both [Al] and [Si(OH)(4)] and was maximal when [Al]< or =4.44 micromol dm(-3) and [Si(OH)(4)]> or =0.50 mmol dm(-3). The enhancement of the Al absorbance signal was not linearly related to [Si(OH)(4)] and the effect was, generally, saturated, for all [Al] tested, at [Si(OH)(4)]> or =0.50 mmol dm(-3). Si(OH)(4) was significantly more effective in enhancing the Al absorbance signal than Mg(NO(3))(2). However, the co-occurrence of 10 mmol dm(-3) Mg(NO(3))(2) and 2 mmol dm(-3) Si(OH)(4) in samples abolished the enhancement due to Si(OH)(4). The presence of Si(OH)(4) in samples could result in an overestimation of the Al content of those samples by as much as 50%. Errors in the measurement of Al in samples containing Si(OH)(4) could be prevented using matrix-matched calibration standards. Our observation could have serious implications for the determination of Al in aqueous samples of both geochemical and biological interest. It may also point towards the application of Si(OH)(4) as a novel and effective matrix modifier in the determination of Al by GFAAS since the inclusion of Si(OH)(4) in standards and samples improved the limit of detection of Al from ca 8 nmol dm(-3) to 3 nmol dm(-3).     

Synthesis, crystal structures, in vitro biological evaluation of zinc(II) and bismuth(III) complexes of 2-acetylpyrazine N(4)-phenylthiosemicarbazone

Two metal complexes formulated as [Zn(L)(2)](2)·H(2)O (1) and [Bi(L)(NO(3))(2)(CH(3)OH)] (2), where HL=2-acetylpyrazine N(4)-phenylthiosemicarbazone, have been synthesized and characterized by elemental analysis, IR, MS, NMR and single-crystal X-ray diffraction studies. Biological studies, carried out in vitro against selected bacteria and the K562 leukemia cell lines, respectively, have shown that the free ligand and its two complexes may be endowed with important biological properties, especially HL with MIC=3.90 μg/mL against Pseudomonas aeruginosa, the zinc(II) complex 1 with IC(50)=1.0 μM against K562 leukemia cell lines, respectively. The compounds HL and 1 may exert their cytotoxicity activity via induced loss of mitochondria membrane potential (MMP).     

Solution, solid state and biological characterization of ruthenium(III)-DMSO complexes with purine base derivatives

Two new complexes of Ru(III) with purine base derivatives, [mer-RuCl(3)(acv)(DMSO-S)(C(2)H(5)OH)].C(2)H(5)OH (1) (acv=acyclovir, DMSO=dimethyl sulfoxide) and [trans-RuCl(4)(guaH)(DMSO-S)].2H(2)O (2) (guaH=protonated molecule of guanine), were prepared from the same Ru(III) precursor, [trans-RuCl(4)(DMSO-S)(2)](-), by substitution of one DMSO-S. Coordination of acv induced also replacement of one chloride by an ethanol molecule. This reactivity difference was explained by striking contrasts in the hydrogen bonding schemes of the two complexes, evidenced in their X-ray crystal structures. In 1 the guanine derivative acyclovir is coordinated to ruthenium through the N(7) atom, while in 2 the protonated guanine molecule is bound through the N(9) atom. Both complexes were also characterized by various physico-chemical methods in the solid state and in the solution. In vitro, the biological activity of 2 and of the previously described complexes [mer-RuCl(3)(acv)(DMSO-S)(CH(3)OH)].0.5CH(3)OH (3) and [mer-RuCl(3)(acv)(DMSO-S)(H(2)O)].H(2)O (4) on tumour cells appear to be very similar to that of NAMI-A (NAMI-A=[ImH][trans-RuCl(4)(DMSO-S)Im]). All compounds are only weakly active on tumour cell proliferation but show an interesting proadhesive effect that suggest possible activity on tumour malignancy.     

Bacillus coagulans tolerance to 1‐ethyl‐3‐methylimidazolium‐based ionic liquids in aqueous and solid‐state thermophilic culture

The use of ionic liquids (ILs) to disrupt the recalcitrant structure of lignocellulose and make polysaccharides accessible to hydrolytic enzymes is an emerging technology for biomass pretreatment in lignocellulosic biofuel production. Despite efforts to reclaim and recycle IL from pretreated biomass, residual IL can be inhibitory to microorganisms used for downstream fermentation. As a result, pathways for IL tolerance are needed to improve the activity of fermentative organisms in the presence of IL. In this study, microbial communities from compost were cultured under high‐solids and thermophilic conditions in the presence of 1‐ethyl‐3‐methylimidazolium‐based ILs to enrich for IL‐tolerant microorganisms. A strain of Bacillus coagulans isolated from an IL‐tolerant community was grown in liquid and solid‐state culture in the presence of the ILs 1‐ethyl‐3‐methylimidazolium acetate ([C2mim][OAc]) or 1‐ethyl‐3‐methylimidazolium chloride ([C2mim][Cl]) to gauge IL tolerance. Viability and respiration varied with the concentration of IL applied and the type of IL used. B. coagulans maintained growth and respiration in the presence of 4 wt% IL, a concentration similar to that present on IL‐pretreated biomass. In the presence of both [C2mim][OAc] and [C2mim][Cl] in liquid culture, B. coagulans grew at a rate approximately half that observed in the absence of IL. However, in solid‐state culture, the bacteria were significantly more tolerant to [C2mim][Cl] compared with [C2mim][OAc]. B. coagulans tolerance to IL under industrially relevant conditions makes it a promising bacterium for understanding mechanisms of IL tolerance and discovering IL tolerance pathways for use in other microorganisms, particularly those used in bioconversion of IL‐pretreated plant biomass. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 30:311–316, 2014     

Regioselective synthesis of 1,3,5-adamantanetriol from 1,3-adamantanediol using Kitasatospora cells

Washed cells (62?mg) of Kitasatospora sp. GF12 in 4?ml buffer (pH 7) catalyzed the regioselective hydroxylation of 60?mM 1,3-adamantanediol [1,3-ad(OH)(2)] to 30.9?mM 1,3,5-adamantanetriol [1,3,5-ad(OH)(3)] over 120?h at 24?°C. Glycerol at 400?mM was added to the reaction mixture to recycle the intracellular NADH/NADPH. Whole cells of GF12, also catalyzed the hydroxylation of 10?mM 1-adamantanol (1-adOH), to 3.6?mM 1,3,5-ad(OH)(3).     

Enrichment,isolation and characterization of fungi tolerant to 1‐ethyl‐3‐methylimidazolium acetate

Aims: This work aimed to characterize microbial tolerance to 1‐ethyl‐3‐methylimidazolium acetate ([C2mim][OAc]), an ionic liquid that has emerged as a novel biomass pretreatment for lignocellulosic biomass. Methods and Results: Enrichment experiments performed using inocula treated with [C2mim][OAc] under solid and liquid cultivation yielded fungal populations dominated by Aspergilli. Ionic liquid‐tolerant Aspergillus isolates from these enrichments were capable of growing in a radial plate growth assay in the presence of 10% [C2mim][OAc]. When a [C2mim][OAc]‐tolerant Aspergillus fumigatus strain was grown in the presence of switchgrass, endoglucanases and xylanases were secreted that retained residual enzymatic activity in the presence of 20% [C2mim][OAc]. Conclusions: The results of the study suggest that tolerance to ionic liquids is a general property of the Aspergilli. Significance and Impact of the Study: Tolerance to an industrially important ionic liquid was discovered in a fungal genera that is widely used in biotechnology, including biomass deconstruction.     

Physiological significance of C-28 hydroxylation in the metabolism of 1alpha,25-dihydroxyvitamin D(2).

In our previous study, we indicated for the first time that C-28 hydroxylation plays a significant role in the metabolism of 1alpha, 25-dihydroxyvitamin D(2) [1alpha,25(OH)(2)D(2)] by identifying 1alpha,24(S),25,28-tetrahydroxyvitamin D(2) [1alpha,24(S),25, 28(OH)(4)D(2)] as a major renal metabolite of 1alpha,25(OH)(2)D(2) [G. S. Reddy and K-Y. Tserng Biochemistry 25, 5328-5336, 1986]. The present study was performed to establish the physiological significance of C-28 hydroxylation in the metabolism of 1alpha, 25(OH)(2)D(2). We perfused rat kidneys in vitro with 1alpha, 25(OH)(2)[26,27-(3)H]D(2) (5 x 10(-10)M) and demonstrated that 1alpha,24(R),25-trihydroxyvitamin D(2) [1alpha,24(R),25(OH)(3)D(2)] and 1alpha,24(S),25,28(OH)(4)D(2) are the only two major physiological metabolites of 1alpha,25(OH)(2)D(2). In the same perfusion experiments, we also noted that there is no conversion of 1alpha,25(OH)(2)D(2) into 1alpha,25,28-trihydroxyvitamin D(2 )[1alpha,25,28(OH)(3)D(2)]. Moreover, 1alpha,24(S),25,28(OH)(4)D(2) is not formed in the perfused rat kidney when synthetic 1alpha,25, 28(OH)(3)D(2) is used as the starting substrate. This finding indicates that C-28 hydroxylation of 1alpha,25(OH)(2)D(2) occurs only after 1alpha,25(OH)(2)D(2) is hydroxylated at C-24 position. At present the enzyme responsible for the C-28 hydroxylation of 1alpha, 24(R),25(OH)(3)D(2) in rat kidney is not known. Recently, it was found that 1alpha,25(OH)(2)D(3)-24-hydroxylase (CYP24) can hydroxylate carbons 23, 24, and 26 of various vitamin D(3) compounds. Thus, it may be speculated that CYP24 may also be responsible for the C-28 hydroxylation of 1alpha,24(R),25(OH)(3)D(2) to form 1alpha, 24(S),25,28(OH)(4)D(2). The biological activity of 1alpha,24(S),25, 28(OH)(4)D(2), determined by its ability to induce intestinal calcium transport and bone calcium resorption in the rat, was found to be almost negligible. Also, 1alpha,24(S),25,28(OH)(4)D(2) exhibited very low binding affinity toward bovine thymus vitamin D receptor. These studies firmly establish that C-28 hydroxylation is an important enzymatic reaction involved in the inactivation of 1alpha,25(OH)(2)D(2) in kidney under physiological conditions.     

Extraction of lignins from aqueous-ionic liquid mixtures by organic solvents

The commercial development of ionic liquids (ILs) to pretreat lignocellulose by dissolution of whole biomass and cellulose precipitation by addition of water is hindered by the absence of an effective technique to recover the lignin content of the biomass from the IL. Three organic solvents [ethyl acetate, 1,4-dioxane, and tetrahydrofuran (THF)] were studied for their ability to form a two-liquid-phase system with water and 1-ethyl-3-methylimidazolium acetate ([C(2)mim][OAc]), and for partitioning model lignins and lignin monomers between the two liquid phases. Ternary diagrams were obtained for three [C(2)mim][OAc]/organic solvent/water systems at 22°C. Partition coefficients were measured for several types of lignin in these three systems. Partition coefficients increase with rising water content in the IL phase, and depend strongly on the type of lignin and on the organic solvent. Partition coefficients rise as the pH of the ionic-liquid-rich phase falls. Small molecule model lignin monomer compounds (guaiacol, syringaldehyde) are also readily extracted from the IL/water system by THF.     

Effects of Aging on the Interaction Between Glutamate, Dopamine, and GABA in Striatum and Nucleus Accumbens of the Awake Rat

The aim of the present study was to investigate, using microdialysis, the effects of aging on the glutamate/dopamine/GABA interaction in striatum and nucleus accumbens of the awake rat. For that, the effects of an increase of the endogenous concentration of glutamate on the extracellular concentration of dopamine and GABA in striatum and nucleus accumbens of young (2-4 months), middle-aged (12-14 months), aged (27-33 months), and very aged (37 months) male Wistar rats were studied. Endogenous extracellular glutamate was selectively increased by perfusing the glutamate uptake inhibitor L-trans-pyrrolidine-3,4-dicarboxylic acid (PDC) through the microdialysis probe. In young rats, PDC (1, 2, and 4 mM) produced a dose-related increase of dialysate concentrations of glutamate in both striatum and nucleus accumbens. PDC also increased dialysate dopamine and GABA in both structures. These increases were significantly correlated with the increases of glutamate but not with the PDC dose used, which strongly suggests that the increases of dopamine and GABA were produced by glutamate. In striatum, there were no significant differences in the dopamine/glutamate and GABA/glutamate correlations between young and aged rats. This means that the effects of glutamate on dopamine and GABA do not change during aging. On the contrary, in the nucleus accumbens of aged rats, the increases of dopamine, when correlated with the increases of glutamate, were significantly lower than in young rats. Moreover, the ratio of dopamine to glutamate increases at maximal increases of glutamate was negatively correlated with aging. On the contrary, the ratio of GABA to glutamate increases in nucleus accumbens was positively correlated with aging, which suggests that the effects of endogenous glutamate on GABA tend to be higher in the nucleus accumbens of aged rats. The findings of this study suggest that aging changes the interaction between endogenous glutamate, dopamine, and GABA in nucleus accumbens, but not in striatum, of the awake rat.     

Synthesis, characterization, DNA binding study and biological activity against Leishmania mexicana of [Cu(dppz)2]BF4

[Cu(dppz)(2)]BF(4) complex has been synthesized by the reaction of [Cu(CH(3)CN)(4)]BF(4) and dipyrido[3,2-A:2',3'-c]phenazine (dppz) in a molar ratio of 1:2. The compound was characterized by fast atom bombardment mass spectrometry, 1H nuclear magnetic resonance, UV-Vis and IR spectroscopies. Absorption and viscometric studies carried out on the interaction of [Cu(dppz)(2)]BF(4) complex with calf thymus DNA suggested that the complex binds by intercalation. No covalent binding was observed. Additionally, the results obtained from electrophoresis showed nuclease activity. The biological activity of the complex was tested in vitro on Leishmania mexicana promastigote cultures. A leishmanicidal effect (LD(30)) was observed in 48 h at concentration of 41 nM. Preliminary studies of the ultrastructure of L. mexicana treated with a sublethal dose of the complex (IC(7)=4.1 nM) for 48 h showed an induction of cytoplasm disorganization, vacuolization and binucleated cells. These findings suggest that the leishmanicidal activity of the title complex could be associated with its interaction with the parasitic DNA.     

Tea catechins and flavonoids from the leaves of Camellia sinensis inhibit yeast alcohol dehydrogenase

Four new quercetin acylglycosides, designated camelliquercetisides A-D, quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (17), quercetin 3-O-[2-O″-(E)-p-coumaroyl][β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (18), quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-β-d-glucoside (19), and quercetin 3-O-[2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (20), together with caffeine and known catechins, and flavonoids (1-16) were isolated from the leaves of Camellia sinensis. Their structures were determined by spectroscopic (1D and 2D NMR, IR, and HR-TOF-MS) and chemical methods. The catechins and flavonoidal glycosides exhibited yeast alcohol dehydrogenase (ADH) inhibitory activities in the range of IC(50) 8.0-70.3μM, and radical scavenging activities in the range of IC(50) 1.5-43.8 μM, measured by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.