Gastric anti-ulcer activity of leaf fractions obtained of polar extract from Wilbrandia ebracteata in mice

Leaf fractions of Wilbrandia ebracteata were investigated for anti-ulcerogenic effects in ethanol and indomethacin-induced gastric ulcer assays in mice. Protective anti-ulcer effects were detected only in the ethanol-induced ulcer assay effects after pre-treatment with MeOH extract, MeOH chlorophyll-free, chlorophyll residue, HEX, DCM, aqueous MeOH fraction, ethyl acetate (EtOAc) and aqueous fractions. A potent anti-ulcerogenic effect was determined after pre-treatment of animals with EtOAc fraction, which was fractionated for isolation of active constituents. Seven flavonoids, 3`,4`,5,6,7,8-hexahydroxyflavonol, orientin, isoorientin, vitexin, isovitexin, luteolin, 6-methoxi-luteolin were isolated from the leaves of W. ebracteata (Cucurbitaceae) by chromatographic methods and identified by their spectral data. The data suggest that flavonoids are active anti-ulcerogenic compounds from leaves of W. ebracteata. The ability of scavenging free radicals was evaluated by DPPH reduction assay by TLC of flavonoids isolated.

Bioactive compounds and antioxidant capacity of exotic fruits and commercial frozen pulps from Brazil

The objective of this work was to characterize exotic fruits (cambuci, araca-boi, camu-camu, jaracatia, araca) and commercial frozen pulps (araca, cambuci, umbu, coquinho, pana, native passion fruit, cagaita) from Brazil in relation to their bioactive compounds contents and antioxidant capacity. Camu-camu (Myrciaria dubia) presented the highest vitamin C and total phenolics contents (397 and 1797 mg/100 g f.w., respectively) and the highest DPPH(center dot) scavenging capacity. Coquinho (Butia capitata) also showed a significant vitamin C content (43 mg/100 g f.w.). Among the commercial frozen pulps, cagaita presented the higher DPPH scavenging activity and inhibition of beta-carotene bleaching. A good correlation between total phenols and DPPH scavenging activity was found for fruits (r = 0.997) and commercial frozen pulps (r = 0.738). However, no correlation was found for total phenols and inhibition of beta-carotene bleaching. Quercetin and kaempferol derivatives were the main flavonoids present in all samples and cyanidin derivatives were detected only in camu-camu. Camu-camu and araca (Psidium guineensis) showed the highest total ellagic acid contents (48 and 63.5 mg/100 g f.w.). All commercial frozen pulps presented lower contents of bioactive compounds and antioxidant capacity than their respective fruits. According to our results, camu-camu and araca might be sources of bioactive compounds.

OCCURRENCE AND ANTIBIOTIC SENSIBILITY PROFILE OF Salmonella spp. ISOLATED FROM PORK MEAT CUTS COMMERCIALIZED IN THE OPEN MARKETS IN PELOTAS, RS (BRAZIL)

The objective of the present study was to evaluate the occurrence of Salmonella spp. in 15 samples of pork meat cuts (T-bone, shank, sausage and ribs) commercialized in open markets of Pelotas (RS, Brazil) and verify the prevalent serovars, and test the isolates profile of sensitivity to several antibiotics of importance in medicine (nalidixic acid, ampicillin, aztreonam, kanamycin, carbenicillin, cephalothin, cefoxitin, ceftriaxone, ciprofloxacin, chloramphenicol, gentamicin, sulfonamide, tetracycline and trimetoprina). Twelve samples (80%) were contaminated by Salmonella enterica, serovars Infantis, Derby, Panama and Typhimurium. All isolates were susceptible to trimetoprin, aztreonam, ciprofloxacin, ceftriaxone and cefoxitin. For the other antibiotics, the pattern of sensitivity varied as serovar. In addition, 39.1% of isolates showed up to be multiresistant.

Stabilization of an amylase from Neurospora crassa by immobilization on highly activated supports

The amylase from Neurospora crassa is an interesting enzyme, having higher stability than amylase from Aspergillus oryzea under a broad range of pH values. Moreover, the N. crassa enzyme may be immobilized on different supports with good retention of enzyme activity. The best stabilizations were achieved using Eupergit C 250 L or glyoxyl agarose, with which the enzyme remained fully active at 60C for 24 h while the soluble enzyme remained about 17%. The glyoxyl agarose immobilized enzyme had high thermostability, high optimal temperature (65C) and broad pH/activity profile, suggesting that this enzyme has potential for food and industrial applications for starch modification.

A new acidic myotoxic, anti-platelet and prostaglandin I(2) inductor phospholipase A(2) isolated from Bothrops moojeni snake venom

Phospholipase A(2) (PLA(2), EC 3.1.1.4), a major component of snake venoms, specifically catalyzes the hydrolysis of fatty acid ester bonds at position 2 of 1,2-diacyl-sn-3-phosphoglycerides in the presence of calcium. This article reports the purification and biochemical/functional characterization of BmooTX-I, a new myotoxic acidic phospholipase A(2) from Bothrops moojeni snake venom. The purification of the enzyme was carried out through three chromatographic steps (ion-exchange on DEAE-Sepharose, molecular exclusion on Sephadex G-75 and hydrophobic chromatography on Phenyl-Sepharose). BmooTX-I was found to be a single-chain protein of 15,000 Da and pI 4.2. The N-terminal sequence revealed a high homology with other acidic Asp49 PLA(2)S from Bothrops snake venoms. It displayed a high phospholipase activity and platelet aggregation inhibition induced by collagen or ADP. Edema and myotoxicity in vivo were also induced by BmooTX-I. Analysis of myotoxic activity was carried out by optical and ultrastructural microscopy, demonstrating high levels of leukocytary infiltrate. Previous treatment of BmooTX-1 with BPB reduced its enzymatic and myotoxic activities, as well as the effect on platelet aggregation. Acidic myotoxic PLA(2)S from Bothrops snake venoms have been little explored and the knowledge of its structural and functional features will be able to contribute for a better understanding of their action mechanism regarding enzymatic and toxic activities. (C) 2008 Elsevier Ltd. All rights reserved.

Cytotoxic activity of a dichloromethane extract and fractions obtained from Eudistoma vannamei (Tunicata: Ascidiacea)

This study consists of the bioassay-guided fractionation of the dichloromethane extract from Eudistoma vannamei and the pharmacological characterization of the active fractions. The dried hydromethanolic extract dissolved in aqueous methanol was partitioned with dichloromethane and chromatographed on a silica gel flash column. The anti-proliferative effect was monitored by the MTT assay. Four of the latest fractions, numbered 14 to 17, which held many chemical similarities amongst each other, were found to be the most active. The selected fractions were tested for viability, proliferation and death induction on cultures of HL-60 promycloblastic leukemia cells. The results suggested that the observed cytotoxicity is related to apoptosis induction. (C) 2007 Elsevier Inc. All rights reserved.

Photochemical production of nitric oxide from a nitrosyl phthalocyanine ruthenium complex by irradiation with light in the phototherapeutic window

The photochemical behavior of [Ru(NO)(NO)(2)pc] (pc = phthalocyanine) is reported in this paper. In addition to ligand localized absorption bands (lambda < 300 nm), the electronic spectrum of this complex in dichloromethane solution was dominated by an intense absorption at 640 nm characterized as Q-bands. Irradiation of [Ru(NO)(NO)(2)pc] at 366 and 660 nm led to the production of nitric oxide (NO) as detected by a NO-sensor. NO production by light irradiation at high energy involved excitation of d(pi)-pi* transition, while a photoinduced electron transfer occurred at long wavelength irradiation. The NO quantum yields varied from 1.4 x 10(-3) to 2.3 x 10(-2) mol einstein(-1), depending on oxygen concentration. (c) 2008 Elsevier B.V. All rights reserved.

Crystal structure of Trypanosoma cruzi dihydroorotate dehydrogenase from Y strain

Trypanosoma cruzi is the etiological agent of Chagas` disease, a pathogenesis that affects millions of people in Latin America. Here, we report the crystal structure of dihydroorotate dehydrogenase (DHODH) from T cruzi strain Y solved at 2.2 angstrom resolution. DHODH is a flavin mononucleotide containing enzyme, which catalyses the oxidation Of L-dihydroorotate to orotate, the fourth step and only redox reaction in the de novo biosynthesis of pyrimidine nucleotides. Genetic studies have shown that DHODH is essential for T cruzi survival, validating the idea that this enzyme can be considered an attractive target for the development of antichagasic drugs. In our work, a detailed analysis of T cruzi DHODH crystal structure has allowed us to suggest potential sites to be further exploited for the design of highly specific inhibitors through the technology of structure-based drug design. (c) 2008 Elsevier Inc. All rights reserved.

Aortas isolated from sinoaortic-denervated rats exhibit rhythmic contractions that are regulated by pharmacologically distinct calcium sources

Sinoaortic denervation is characterized by arterial pressure lability, without sustained hypertension. Aortas isolated from rats with sinoaortic denervation present rhythmic contractions. We studied the participation of distinct Ca2+ sources in the maintenance of the oscillations. Three days after the surgeries, aortic rings were placed in an organ chamber, and the incidence of aortas presenting rhythmic contractions was measured. Specific drugs were employed to analyse the participation of the Ca2+ released from the sarcoplasmic reticulum [2-APB (diphenylborinic acid 2-aminoethyl ester), thapsigargin and ryanodine] and external Ca2+ entry [Bay K 8644, verapamil and DMB (dimethylbenzyl amiloride)] on the rhythmic contractions. Additionally, we verified the effects of chloride channel blocker NPPB [5-nitro-2-(3-phenylpropylamino)benzoic acid] on the maintenance of the rhythmic contractions. Under phenylephrine stimulus, sinoaortic-denervated rat aortas exhibited rhythmic contractions in the frequency of 4.5 +/- 0.50 cycles/min. and an amplitude of 0.465 +/- 0.05 g. 2-APB, thapsigargin and ryanodine inhibited the rhythmic contractions. Bay K 8644 increased the oscillations, reaching maximum values with a concentration of 50 nM (18.5 +/- 2.5 cycles/min.). The rhythmic contractions were inhibiting by verapamil and Ca2+-free solution. DMB and NPPB did not alter the oscillations. In conclusion, we observed that aorta isolated from sinoaortic-denervated rats present rhythmic contractions. Moreover, drugs that impaired intracellular Ca2+ release from sarcoplasmic reticulum interrupted the oscillations. The oscillations also depend on the extracellular Ca2+ entry through L-type Ca2+.

Neuropharmacological effects in mice of Lychnophora species (Vernonieae, Asteraceae) and anticonvulsant activity of 4,5-di-O-[E]-caffeoylquinic acid isolated from the stem of L-rupestris and L-staavioides

Aiming at contributing with the search for neuroactive substances from natural sources, we report for the first time antinociceptive and anticonvulsant effects of some Lychnophora species. We verify the protective effects of polar extracts (600 mg/kg, intraperitoneally), and methanolic fractions of L. staavioides and L. rupestris (100 mg/kg, intraperitoneally) in pentylenetetrazole-induced seizures on mice. Previously, a screening was accomplished, evaluating the antinociceptive central activity (hot plate test), with different extracts of L. rupestris, L. staavioides and L. diamantinana. It was possible to select the possible extracts of Lychnophora with central nervous system activity. Some of the active extracts were submitted to fractionation and purification process and the methanolic fractions of L. rupestris (stem) and L. staavioides (stem), with anticonvulsant properties (100 mg/kg, intraperitoneally), yielded 4,5-di-O-[E]-caffeoylquinic acid. This substance was injected intraperitoneally in mice and showed anticonvulsant effect against pentylenetetrazole-induced seizures at doses of 25 and 50 mg/kg. It has often been shown that seizures induced by pentylenetetrazole are involved in inhibition and/or attenuation of GABAergic neurotransmission. However, other systems of the central nervous system such as adenosinergic and glutamatergic could be involved in the caffeoylquinic acid effects. Further studies should be conducted to verify that the target receptor could be participating in this anticonvulsant property. Although other investigations have reported a series of biological activities from Lychnophora species, this is the first report of central analgesic and anticonvulsant activity in species of this genus.

Isolation and functional characterization of proinflammatory acidic phospholipase A(2) from Bothrops leucurus snake venom

In the present study, an acidic PLA(2), designated BI-PLA(2), was isolated from Bothrops leucurus snake venom through two chromatographic steps: ion-exchange on CM-Sepharose and hydrophobic chromatography on Phenyl-Sepharose. Bl-PLA(2) was homogeneous on SDS-PAGE and when submitted to 2D electrophoresis the molecular mass was 15,000 Da and pl was 5.4. Its N-terminal sequence revealed a high homology with other Asp49 acidic PLA(2)s from snake venoms. Its specific activity was 159.9 U/mg and the indirect hemolytic activity was also higher than that of the crude venom. Bl-PLA(2) induced low myotoxic and edema activities as compared to those of the crude venom. Moreover, the enzyme was able to induce increments in IL-12p40, TNF-alpha, IL-1 beta and IL-6 levels and no variation of IL-8 and IL-10 in human PBMC stimulated in vitro, suggesting that Bl-PLA2 induces proinflammatory cytokine production by human mononuclear cells. Bothrops leucurus venom is still not extensively explored and knowledge of its components will contribute for a better understanding of its action mechanism. (C) 2011 Elsevier Inc. All rights reserved.

The bimolecular sensitization of nitric oxide release from weak interacting ruthenium units

This work reports on the bimolecular sensitization of nitric oxide release from cis-[Ru(bpy)(2)(iso)-NO](PF(6))(3) (1) (iso = isoquinoline and bpy = 2,2`- bipyridine) by irradiating the MLCT transition of the chloro analog cis-[Ru(bpy) 2(iso) Cl] PF6 (2). The compounds displayed peaks in the ESI-MS spectra at m/z 749.1 and m/z 578.1 ascribed, respectively, to ([1(NO(o))-2PF(6)center dot CH(3)OH](2+)) and ([2-PF(6)](+)). In the cyclic voltammograms, the nitrosyl complex presented two redox waves related to the NO ligand at 0.48 and -0.37 V (versus Ag/AgCl, NO(+/0/-1) processes), while the sensitizer showed two reversible waves at 0.79 and -1.46 V (versus Ag/AgCl, Ru(2+/3+) and bpy(0/-1), respectively). The most important feature of this system is that the nitrosyl compound does not have significant absorption in the visible region, while the sensitizer has an intense band centered at 496 nm. The irradiation of an equimolar mixture of the two compounds in an ethanol: water solution (v: v) with light of lambda > 500 nm leads to NO release, as probed by amperometric measurements. The variational method was applied, showing that the two compounds self-assembly in solution with a 1: 1 stoichiometry. Fluorescence spectra acquired at 77 K provided the E(0-0) for the system and, from the thermodynamic cycle it was estimated that the photoinduced electron transfer between the species has a Delta G value of -1.59 eV. (C) 2011 Elsevier B. V. All rights reserved.

Antileishmanial Sesquiterpenes from the Brazilian Red Alga Laurencia dendroidea

Investigation of the bioactive crude extracts from two populations of the red alga Laurencia dendroidea from the southeastern Brazilian coast led to the identification of five sesquiterpenes: (+)-obtusane (1), a triquinane derivative (2), (-)-elatol (3), obtusol (4), and cartilagineol (5). An antileishmanial bioassay against Leishmania amazonensis was conducted for crude lipophilic extracts and for sesquiterpenes 2, 3, and 4. Compounds 3 and 4 displayed in vitro and in vivo leishmanicidal activity and very low cytotoxicity.

Structural characterization of exopolysaccharides from biofilm of a cariogenic streptococci

Soluble (EPS-SOL), as well as insoluble extracellular polysaccharide (EPS-INSOL), extracted from biofilm of Streptococcus mutans, were analyzed by nuclear magnetic resonance spectroscopy, methylation analysis, and a controlled Smith degradation. EPS-SOL was a branched alpha-glucan containing a (1 -> 6)-and (1 -> 3)-linkages. EPS-INSOL was a branched alpha-glucan with similar linkages, but with a (1 -> 3)-linked main-chain partially substituted at O-6 with Glcp-(1 -> 6)-Glcp-side chains. Biofilm EPS had a distinct chemical structure compared with those synthesized by plankton cells or by purified enzymes from S. mutans, which could indicate different mechanisms for its degradation. (C) 2011 Published by Elsevier Ltd.

Visualizing inhibition of fatty acid synthase through mass spectrometric analysis of mitochondria from melanoma cells

Fatty acid synthase (FASN) is the metabolic enzyme responsible for the endogenous synthesis of the saturated long-chain fatty acid palmitate. In contrast to most normal cells, FASN is overexpressed in a variety of human cancers including cutaneous melanoma, in which its levels of expression are associated with a poor prognosis and depth of invasion. Recently, we have demonstrated the mitochondrial involvement in FASN inhibition-induced apoptosis in melanoma cells. Herein we compare, via electrospray ionization mass spectrometry (ESI-MS), free fatty acids (FFA) composition of mitochondria isolated from control (EtOH-treated cells) and Orlistat-treated B16-F10 mouse melanoma cells. Principal component analysis (PCA) was applied to the ESI-MS data and found to separate the two groups of samples. Mitochondria from control cells showed predominance of six ions, that is, those of m/z 157 (Pelargonic, 9:0), 255 (Palmitic, 16:0), 281 (Oleic, 18:1), 311 (Arachidic, 20:0), 327 (Docosahexaenoic, 22:6) and 339 (Behenic, 22:0). In contrast, FASN inhibition with Orlistat changes significantly mitochondrial FFA composition by reducing synthesis of palmitic acid, and its elongation and unsaturation products, such as arachidic and behenic acids, and oleic acid, respectively. ESI-MS of mitochondria isolated from Orlistat-treated cells presented therefore three major ions of m/z 157 (Pelargonic, 9:0), 193 (unknown) and 199 (Lauric, 12:0). These findings demonstrate therefore that FASN inhibition by Orlistat induces significant changes in the FFA composition of mitochondria. Copyright (C) 2011 John Wiley & Sons, Ltd.