Synergism on antioxidant activity between natural compounds optimized by response surface methodology

Despite the increase in the use of natural compounds in place of synthetic derivatives as antioxidants in food products, the extent of this substitution is limited by cost constraints. Thus, the objective of this study was to explore the synergism on the antioxidant activity of natural compounds, for further application in food products. Three hydrosoluble compounds (x(1) = caffeic acid, x(2) = carnosic acid, and x(3) = glutathione) and three liposoluble compounds (x(1) = quercetin, x(2) = rutin, and x(3) = genistein) were mixed according to a ""centroid simplex design"". The antioxidant activity of the mixtures was analyzed by the ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAL) methodologies, and activity was also evaluated in an oxidized mixed micelle prepared with linoleic acid (LAOX). Cubic polynomial models with predictive capacity were obtained when the mixtures were submitted to the LAOX methodology ((y) over cap = 0.56 x(1) + 0.59 x(2) + 0.04 x(3) + 0.41 x(1)x(2) - 0.41 x(1)x(3) - 1.12 x(2)x(3) - 4.01 x(1)x(2)x(3)) for the hydrosoluble compounds, and to FRAP methodology ((y) over cap = 3.26 x(1) + 2.39 x(2) + 0.04 x(3) + 1.51 x(1)x(2) + 1.03 x(1)x(3) + 0.29 x(1)x(3) + 3.20 x(1)x(2)x(3)) for the liposoluble compounds. Optimization of the models suggested that a mixture containing 47% caffeic acid + 53% carnosic acid and a mixture containing 67% quercetin + 33% rutin were potential synergistic combinations for further evaluation using a food matrix.

The semi-synthetic kaurane ent-16 alpha-methoxykauran-19-oic acid induces vascular relaxation and hypotension in rats

The present work investigates the mechanisms involved in the vasorelaxant effect of ent-16 alpha-methoxykauran-19-oic acid (KA-OCH(3)), a semi-synthetic derivative obtained from the kaurane-type diterpene ent-kaur-16-en-19-oic acid (kaurenoic acid). Vascular reactivity experiments were performed in aortic rings isolated from male Wistar rats using standard muscle bath procedures. The cytosolic calcium concentration ([Ca(2+)]c) was measured by confocal microscopy using the fluorescent probe Fluo-3 AM. Blood pressure measurements were performed in conscious rats. KA-OCH(3) (10,50 and 100 mu mol/l) inhibited phenylephrine-induced contraction in either endothelium-intact or endothelium-denuded rat aortic rings. KA-OCH(3) also reduced CaCl(2)-induced contraction in a Ca(2+)-free solution containing KCl (30 mmol/l) or phenylephrine (0.1 mu mol/l). KA-OCH(3) (0.1-300 mu mol/l) concentration-dependently relaxed endothelium-intact and endothelium-denuded aortas pre-contracted with either phenylephrine or KCl, to a greater extent than kaurenoic acid. Moreover, a Ca(2+) mobilisation study showed that KA-OCH(3) (100 mu mol/l) inhibited the increase in Ca(2+) concentration in smooth muscle and endothelial cells induced by phenylephrine or KCl. Pre-incubation of intact or denuded aortic rings with N(G)-nitro-L-arginine methyl ester (L-NAME, 100 mu mol/l), 7-nitroindazole (100 mu mol/l), wortmannin (0.5 mu mol/l) and 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ 1 mu mol/l) produced a rightward displacement of the KA-OCH(3) concentration-response curve. Intravenous administration of KA-OCH(3) (1-10 mg/kg) reduced mean arterial blood pressure in normotensive rats. Collectively, our results show that KA-OCH(3) induces vascular relaxation and hypotension. The mechanisms underlying the cardiovascular actions of KA-OCH(3) involve blockade of Ca(2+) influx and activation of the NO-cGMP pathway. (C) 2011 Elsevier B.V. All rights reserved.

Ruthenium-nitrite complex as pro-drug releases NO in a tissue and enzyme-dependent way

Nitric oxide (NO) plays an important role in the control of the vascular tone and the most often employed NO donors have limitations due to their harmful side-effects. In this context, new NO donors have been prepared, in order to minimize such undesirable effects. cis-[Ru(bpy)(2)(py)NO(2)](PF(6)) (RuBPY) is a new nitrite complex synthesized in our laboratory that releases NO in the presence of the vascular tissue only. In this work the vasorelaxation induced by this NO donor has been studied and compared to that obtained with the well known NO donor SNP. The relaxation induced by RuBPY is concentration-dependent in denuded rat aortas pre-contracted with phenylephrine (EC(50)). This new compound induced relaxation with efficacy similar to that of SNP, although its potency is lower. The time elapsed until maximum relaxation is achieved (E(max) = 240 s) is similar to measured for SNP (210 s). Vascular reactivity experiments demonstrated that aortic relaxation by RuBPY is inhibited by the soluble guanylyl-cyclase inhibitor 1H-[1,2,4] oxadiozolo[4,3-a]quinoxaline-1-one (ODQ 1 mu M). In a similar way, 1 mu M ODQ also reduces NO release from the complex as measured with DAF-2 DA by confocal microscopy. These findings suggest that this new complex RuBPY that has nitrite in its structure releases NO inside the vascular smooth muscle cell. This ruthenium complex releases significant amounts of NO only in the presence of the aortic tissue. Reduction of nitrite to NO is most probably dependent on the soluble guanylyl-cyclase enzyme, since NO release is inhibited by ODQ. (C) 2011 Elsevier Inc. All rights reserved.

Endogenous cannabinoids induce fever through the activation of CB(1) receptors

Background and purpose: The effects of centrally administered cannabinoids on body core temperature (Tc) and the contribution of endogenous cannabinoids to thermoregulation and fever induced by lipopolysaccharide (LPS) (Sigma Chem. Co., St. Louis, MO, USA) were investigated. Experimental approach: Drug-induced changes in Tc of male Wistar rats were recorded over 6 h using a thermistor probe (Yellow Springs Instruments 402, Dayton, OH, USA) inserted into the rectum. Key results: Injection of anandamide [(arachidonoylethanolamide (AEA); Tocris, Ellisville, MO, USA], 0.01-1 mu g i.c.v. or 0.1-100 ng intra-hypothalamic (i.h.), induced graded increases in Tc (peaks 1.5 and 1.6 degrees C at 4 h after 1 mu g i.c.v. or 10 ng i.h.). The effect of AEA (1 mu g, i.c.v.) was preceded by decreases in tail skin temperature and heat loss index (values at 1.5 h: vehicle 0.62, AEA 0.48). Bell-shaped curves were obtained for the increase in Tc induced by the fatty acid amide hydrolase inhibitor [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate (Cayman Chemical Co., Ann Arbor, MI, USA) (0.001-1 ng i.c.v.; peak 1.9 degrees C at 5 h after 0.1 ng) and arachidonyl-2-chloroethylamide (ACEA; Tocris) (selective CB(1) agonist; 0.001-1 mu g i.c.v.; peak 1.4 degrees C 5 h after 0.01 mu g), but (R,S)-(+)-(2-Iodo-5-nitrobenzoyl)-[1-(1-methyl-piperidin-2-ylmethyl)-1H-indole-3-yl] methanone (Tocris) (selective CB(2) agonist) had no effect on Tc. AEA-induced fever was unaffected by i.c.v. pretreatment with 6-Iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indole-3-yl](4-methoxyphenyl) methanone (Tocris) (selective CB(2) antagonist), but reduced by i.c.v. pretreatment with N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251; Tocris) (selective CB(1) antagonist). AM251 also reduced the fever induced by ACEA or LPS. Conclusions and implications: The endogenous cannabinoid AEA induces an integrated febrile response through activation of CB(1) receptors. Endocannabinoids participate in the development of the febrile response to LPS constituting a target for antipyretic therapy.

Purification and characterization of Ts15, the first member of a new alpha-KTX subfamily from the venom of the Brazilian scorpion Tityus serrulatus

Voltage-gated potassium channel toxins (KTxs) are basic short chain peptides comprising 23-43 amino acid residues that can be cross-linked by 3 or 4 disulfide bridges. KTxs are classified into four large families: alpha-, beta-, gamma- and kappa-KTx. These peptides display varying selectivity and affinity for K(v) channel subtypes. In this work, a novel toxin from the Tityus serrulatus venom was isolated, characterized and submitted to a wide electrophysiological screening on 5 different subtypes of Nay channels (Na(V)1.4; Na(V)1.5; Na(V)1.6; Na(V)1.8 and DmNa(V)1) and 12 different subtypes of Kv channels (K(V)1.1 - K(V)1.6; K(V)2.1; K(V)3.1; K(V)4.2; K(V)4.3; Shaker IR and ERG). This novel peptide, named Ts15, has 36 amino acids, is crosslinked by 3 disulfide bridges, has a molecular mass of 3956 Da and pI around 9. Electrophysiological experiments using patch clamp and the two-electrode voltage clamp techniques show that Ts15 preferentially blocks K(V)1.2 and K(V)1.3 channels with an IC(50) value of 196 +/- 25 and 508 +/- 67 nM, respectively. No effect on Na(V) channels was observed, at all tested concentrations. Since Ts15 shows low amino acid identity with other known KTxs, it was considered a bona fide novel type of scorpion toxin. Ts15 is the unique member of the new alpha-Ktx21 subfamily and therefore was classified as alpha-Ktx21.1. (C) 2011 Elsevier Ltd. All rights reserved.

Brazilian Propolis: Seasonal Variation of the Prenylated p-Coumaric Acids and Antimicrobial Activity

Brazilian green propolis, which is used in food and beverages to improve health and to prevent diseases, demostrates antioxidant, antimutagenic, and antimicrobial activities. Most biological activities are thought to be related to the high levels of drupanin, artepillin C, and baccharin, which are compounds also present in Baccharis dracunculifolia D.C. (Asteraceae). Since propolis chemical composition depends on the region and the period of collection, as well as its plant origin, the effect of seasonal variation on the both content of prenylated p-coumaric acids and in vitro antimicrobial activity of Brazilian propolis from four different sites, was performed. The results showed that MIC values ranged from 100 to 300 mu g/mL against both Staphylococcus aureus and Kocuria rhizophila, while none of the propolis samples was active against Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. HPLC analysis showed that the content of drupanin, artepillin C, and baccharin varied throughout the year, as well as among the different study sites. Also, it is suggested that Baccharis dracunculifolia is the main botanical source of Brazilian propolis in sites I and 2, while in sites 3 and 4, other plant species are also used by bees to produce propolis. All the evaluated propolis samples exhibited similar antibacterial activity, but different contents of prenylated p-coumaric acids throughout the year.

Validation of a gas chromatographic method to quantify sesquiterpenes in copaiba oils

Copaifera species (Leguminoseae) are popularly known as ""copaiba"" or ""copaiva"". The oleoresins obtained from the trunk of these species have been extensively used in folk medicine and are commercialized in Brazil as crude oil and in several pharmaceutical and cosmetic products. This work reports a complete validated method for the quantification of beta-caryophyllene, alpha-copaene, and alpha-humulene in distinct copaiba oleoresins available commercially. Thus, essential oil samples (100 mu L) were dissolved in 20 mL of hexanes containing internal standard (1,2,4,5-tetramethylbenzene, 3.0 mM) in a 25 mL glass flask. A 1 mu L aliquot was injected into the GC-FID system. A fused-silica capillary column HP-5, coated with 5% phenylmethylsiloxane was used for this study. The developed method gave a good detection response with linearity in the range of 0.10-18.74 mM. Limits of detection and quantitation variety ranged between 0.003 and 0.091 mM. beta-Caryophyllene, alpha-copaene, and alpha-humulene were recovered in a range from 74.71% to 88.31%, displaying RSD lower than 10% and relative errors between -11.69% and -25.30%. Therefore, this method could be considered as an analytical tool for the quality control of different Copaifera oil samples and its products in both cosmetic and pharmaceutical companies. (C) 2010 Elsevier B.V. All rights reserved.

Schistosomicidal and trypanocidal structure-activity relationships for (+/-)-licarin A and its (-)- and (+)-enantiomers

(+/-)-Licarin A (1) was obtained by oxidative coupling, and its enantiomers, (-)-licarin A (2) and (+)-licarin A (3), were resolved by chiral HPLC. Schistosomicidal and trypanocidal activities of these compounds were evaluated in vitro against Schistosoma mansoni adult worms and trypomastigote forms of Trypanosoma cruzi. The racemic mixture (1) displayed significant schistosomicidal activity with an LC(50) value of 53.57 mu M and moderate trypanocidal activity with an IC(50) value of 127.17 mu M. On the other hand, the (-)-enantiomer (2), displaying a LC(50) value of 91.71 mu M, was more active against S. mansoni than the (+)-enantiomer (3), which did not show activity. For the trypanocidal assay, enantiomer 2 showed more significant activity (IC(50) of 23.46 mu M) than enantiomer 3, which showed an IC(50) value of 87.73 mu M. Therefore, these results suggest that (+/-)-licarin A (1) and (-)-licarin A (2) are promising compounds that could be used for the development of schistosomicidal and trypanocidal agents. (C) 2011 Elsevier Ltd. All rights reserved.

Schistosomicidal Evaluation of Zanthoxylum naranjillo and its Isolated Compounds against Schistosoma mansoni Adult Worms

Chemical investigation of the EtOAc fraction (EF) obtained from the ethanolic extract of Zanthoxylum naranjillo (Rutaceae) leaves (EE) by preparative HPLC resulted in the isolation of protocatechuic acid (1), gallic acid (2), p-hydroxybenzoic acid (3), and 5-O-caffeoylshikimic acid (4). This is the first time that the presence of compounds 1-4 in Z. naranjillo has been reported. Compounds 1-4, the EE, and EF were tested in vitro against Schistosoma mansoni adult worms. The results showed that the S. mansoni daily egg production decreased by 29.8%, 13.5% 28.4%, 17.7%, 16.3%, and 6.4%, respectively. Compounds 1 and 3 were also able to separate adult worm pairs into male and female. This activity may be correlated with the reduction in egg production, since 1 and 3 showed better inhibitory properties compared with 2 and 4.

Determinants of beta-lactam resistance in meningitis-causing Enterobacteriaceae in Brazil

This study analyzed resistance determinants in extended-spectrum beta-lactamase (ESBL)-producing enterobacteria and the epidemiology of 11 Escherichia coli isolates obtained from meningitis patients in a region of Brazil from 2000 to 2005. ESBL-encoding genes and their genetic environment were investigated by PCR and sequencing. The gene bla(CTX-M-2) was identified in 3 different enterobacteria (E. coli. Serratia marcescens, and Proteus mirabilis) downstream of the insertion sequence ISCR1 (localized in class 1 integrons), hut not as part of the resistance cassettes region. Multi locus sequence typing (MLST) was used to investigate genetic relationships between the 11 E. coil isolates in this study and strains associated with meningitis in the E. coil MLST database. MLST analysis indicated high genetic diversity among isolates, and no significant genetic relationship was identified with meningitis-causing E. coil in the database. The results in this report reinforce the need to be attentive to meningitis suspected to be due to ESBL-producing enterobacterial isolates, especially where ESBL epidemiology is well known.

Metformin pharmacokinetics in nondiabetic pregnant women with polycystic ovary syndrome

The use of metformin throughout gestation by pregnant women with polycystic ovary syndrome (PCOS) significantly reduces the number of first trimester spontaneous abortions and the rate of occurrence of gestational diabetes. The objective of this study was to investigate the pharmacokinetics and the placental transfer of metformin in pregnant women with PCOS. Eight pregnant women with PCOS taking 850 mg metformin every 12 h during the third trimester of pregnancy were evaluated. Maternal blood samples were collected at steady state during the dose interval (0-12 h). Maternal and umbilical cord blood samples were also obtained at delivery. Metformin plasma concentrations were analyzed by high-performance liquid chromatography, and pharmacokinetic parameters were determined using a non-compartmental model. Data are reported as median and minimum and maximum values. Metformin pharmacokinetic parameters were: t(A1/2), 3.8 (2.8-5.4) h; t(max), 2.0 (0.5-3.0) h; C(max), 1.4 (0.5-2.1) mg/L; C(mean), 0.5 (0.2-0.9) mg/L; AUC(0-12), 6.4 (1.1-9.2) mg h/L; Cl/f, 105 (60-274) L/h; Vd/f, 551 (385-1173) L; median fluctuation, 89 (79-95)%. Umbilical/maternal metformin plasma concentration ratios were 0.7 (0.4-1.3). Metformin oral clearance (Cl/f) had increased in our patients relative to nonpregnant healthy volunteers or diabetic patients. Therefore, lower plasma metformin concentrations were observed for nondiabetic pregnant women with PCOS. Future studies should be conducted to demonstrate the therapeutic efficacy of metformin during pregnancy. Caution is warranted as umbilical/maternal metformin plasma concentrations ratios of around 0.7 require metformin dosage adjustment.

High selectivity microporous silica membranes for lactic acid dehydration

Lactic acid (LA) has significant market potential for many industries including food, cosmetics, pharmaceuticals, medical and biodegradable materials. Production of LA usually begins with the fermentation of glucose but subsequent stages for the enrichment of lactic acid are complex and energy intensive and could be minimised using water selective membrane technology. In this work, we trialled a highly selective hydrostable carbonised template molecular sieve silica (CTMSS) membrane for the dehydration of a 15 vol% aqueous lactic acid solution with 0.1 vol% glucose. CTMSS membrane films were developed by dip-coating ceramic substrates with silica sols made using the acid catalysed sol-gel process. Permeation was performed by feeding LA/glucose solution to the membrane cell at 18°C in a standard pervaporation setup. The membrane showed selective transport of water from the aqueous feed to the permeate while glucose was not detected. CTMSS membrane permeate flux stabilised at 0.2 kg.m-2.hr-1 in 3.9 hours, and reduced LA to lower than 0.2 vol%. Flux through the CTMSS micropores was activated, displaying increased initial flux to 1.58 kg.m-2.hr-1 at 60°C. To enrich a 1 l.min-1 stream to 85% LA in a single stage, a minimum membrane area of 324 m2 would be required at 18°C. Increased operating temperature to 80°C significantly reduced this area to 24 m2 but LA levels in the permeate stream increased to 0.5 vol%. The highly selective CTMSS membrane technology is an ideal candidate for LA purification. CTMSS membrane systems operate stably in aqueous systems leading to potential cost reductions in LA processing for future markets.

The influence of joint position on the dynamics of perception-action coupling

Six right-handed subjects performed rhythmic flexion and extension movements of the index finger in time with an auditory metronome. On each block of trials, the wrist of the response hand was placed in a extended, neutral or flexed position. In the flex-on-the-beat condition, subjects were instructed to coordinate maximum excursion in the direction of finger flexion with each beat of the metronome. In the extend-on-the-beat condition, subjects were instructed to coordinate maximum excursion in the direction of finger extension with each beat of the metronome. The frequency of the metronome was increased from 2.00 Hz to 3.75 Hz in 8 steps (8 s epochs) of 0.25 Hz. During trials prepared in the extend-on-the-beat pattern, all subjects exhibited transitions to either a flex-on-the-beat pattern or to phase wandering as the frequency of pacing was increased. The time at which these transitions occurred was reliably influenced by the position of the wrist. Four subjects exhibited qualitative departures from the flex-on-the-beat pattern at pacing frequencies that were greater than those at which the extend-on-the-beat pattern could be maintained. The lime at which these departures occurred was not influenced by the position of the wrist. These results are discussed with reference to the constraints imposed on the coordination dynamics by the intrinsic properties of the neuromuscular-skeletal system.

Modeling ex vivo hematopoiesis using chemical engineering metaphors

Ex vivo hematopoiesis is increasingly used for clinical applications. Models of ex vivo hematopoiesis are required to better understand the complex dynamics and to optimize hematopoietic culture processes. A general mathematical modeling framework is developed which uses traditional chemical engineering metaphors to describe the complex hematopoietic dynamics. Tanks and tubular reactors are used to describe the (pseudo-) stochastic and deterministic elements of hematopoiesis, respectively. Cells at any point in the differentiation process can belong to either an immobilized, inert phase (quiescent cells) or a mobile, active phase (cycling cells). The model describes five processes: (1) flow (differentiation), (2) autocatalytic formation (growth),(3) degradation (death), (4) phase transition from immobilized to mobile phase (quiescent to cycling transition), and (5) phase transition from mobile to immobilized phase (cycling to quiescent transition). The modeling framework is illustrated with an example concerning the effect of TGF-beta 1 on erythropoiesis. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Thermochromism and structure of piperazinium tetrachlorocuprate(II) complexes

The tetrachlorocuprate(II) ion can crystallize in two different structures with the piperazinium dication (pipzH(2)). Both structures contain discrete CuCl42- species. A yellow compound (pipzH(2))[CuCl4]. 2H(2)O (1) is monoclinic (C2/c, Z = 4, a = 10.538(3) Angstrom, b = 7.4312(5) Angstrom, c = 17.281(4) Angstrom, beta = 111.900(10)degrees) and contains the CuCl42- ion as a distorted tetrahedron. A green compound (pipzH(2))(2)[CuCl4]. Cl-2. 3H(2)O (2) is triclinic (P (1) over bar, Z = 2, a = 9.264(3) Angstrom, b = 10.447(2) Angstrom, c = 11.366(2) Angstrom, alpha = 68.38 degrees, beta = 82.86(2)degrees, gamma = 83.05(2)degrees) and contains the CuCl42- ion with a square planar geometry. This latter compound shows thermo/photochromism, changing from green to yellow upon heating or laser irradiation.