Ana Claudia Granato

Cytotoxic and neurotoxic activities in extracts of marine sponges (porifera) from southeastern Brazilian coast

This work reports the results of a screening program based on marine sponge extracts from the southeastern Brazilian coast, covering cytotoxic and neurotoxic activities. Polar and non-polar extracts of 24 sponge species collected by scuba diving in rocky shores, from 1996 to 2000, were screened for haemolytic, cytotoxic and neurotoxic activities. Fifty-four percent (13/24) of the sponge extracts tested exhibited from median to high toxicity in at least one of the toxicity bioassays performed. Amphimedon sp. and Arenosclera brasiliensis Muricy and Ribeiro, 1999 induced haemolysis in mice erythrocytes at small concentrations. Aaptos sp. and Geodia corticostylifera Hajdu, Muricy, Custodio, Russo and Peixinho, 1992 extracts lysed the sea-urchin eggs, while Axinella aff. corrugata George and Wilson, 1919, Mycale laxissima Duchassaing and Michelotti, 1864, A. brasiliensis and Raspailia elegans Bourm-Esnauls, 1973, inhibited mitosis and its development. The extracts of G. gibberosa Lamarck, 1815 and Stelletta sp. showed specific neurotoxic activity, while G. corticostylifera and A. brasiliensis extracts induced blockage of action potential conduction in crustacean nerve, maybe due to their lytic properties.

Two unprecedented dibromotyrosine-derived alkaloids from the Brazilian endemic marine sponge Aplysina caissara.

Two new bromotyrosine-derived alkaloids, caissarine A (1) and caissarine B (2), along with three known biogenetically related alkaloids, aeroplysinin-1, fistularin-3, and the artifact of isolation 2-(3,5-dibromo-4-dimethoxy-1-hydroxy-2,5-cyclohexadien-1-yl)ethanamide, have been isolated from Aplysina caissara, an endemic species of marine sponge from the Southeastern Brazilian coast. The alkaloids have been identified by analysis of spectroscopic data. While caissarine A has a 2-hydroxyagmatine moiety in its structure, caissarin B is the first naturally occurring compound encompassing the unprecedented 1,7-diamino-3-hydroxyheptane moiety.

Produtos naturais da ascídia Botrylloides giganteum, das esponjas Verongula gigantea, Ircinia felix, Cliona delitrix e do nudibrânquio Tambja eliora, da costa do Brasil

Two new marine metabolites, 3Z, 6Z, 9Z-dodecatrien-1-ol (1) from the ascidian Botrylloides giganteum and 4H-pyran-2ol acetate from the sponge Ircinia felix (4) are herein reported. The known bromotyrosine compounds, 2-(3,5-dibromo-4-methoxyphenyl)-N,N,N-dimethylethanammonium (2) and 2,6-dibromo-4-(2-(trimethylammonium)ethyl)phenol (3), have been isolated from the sponge Verongula gigantea. Serotonin (5) is reported for the first time from the sponge Cliona delitrix, and tambjamines A (15) and D (16) isolated as their respective salts from the nudibranch Tambja eliora. Only tambjamine D presented cytotoxicity against CEM (IC50 12.2 µg/mL) and HL60 (IC50 13.2 µg/mL) human leukemya cells, MCF-7 breast cancer cells (IC50 13.2 µg/mL), colon HCT-8 cancer cells (IC50 10.1 µg/mL) and murine melanoma B16 cancer cells (IC50 6.7 µg/mL).

Preliminary Studies for Cephamycin C Purification Technique

A study was made for purification of cephamycin C from fermentation of Streptomyces clavuligerus. Initially, the culture broth was clarified by microfiltration and ultrafiltration, after which the resulting permeates were subjected to nonspecific adsorption and ion-exchange chromatography on resin columns. The antibiotic activity was measured by the biological method at each stage by assaying its activity against the Escherichia coli ESS, super sensitive to β-lactam antibiotic. The purification processes were assessed in relation to the variables affecting each step. The purification efficiency by nonspecific adsorption was monitored by UV spectrophotometry, while the ion-exchange adsorption fractions were assessed by NMR spectroscopy. Some of the fractions obtained during purification were also analyzed by mass spectrometry (LC/MS and LC/MS/MS) to identify the cephamycin C molecule. These preliminary results proved the process feasibility.

Growing kinetics and antimicrobial activity of Streptomyces tubercidicus crude extracts

1 Federal University of Sao Carlos, DMP, CCBS, UFSCar Rodovia Washington Luis Km 235, Sao Carlos SP, Brazil 2 Biotechnology Post Graduate Program, UFSCar Rodovia Washington Luis Km 235, Sao Carlos SP, Brazil 3 Federal University of Sao Carlos, DEQ, CCET, UFSCar Rodovia Washington Luis Km 235, Sao Carlos SP, Brazil 4 Universite de Montreal, campus Saint-Hyacinthe, 3200 Rue Sicotte Quebec, J2S 7C6 Canada

Electrochemical production and use of free chlorine for pollutant removal: an experimental design approach

ABSTRACT The present paper presents the study of (1) the optimization of electrochemical-free chlorine production using an experimental design approach, and (2) the application of the optimum conditions obtained for the application in photo-assisted electrochemical degradation of simulated textile effluent. In the experimental design the influence of inter-electrode gap, pH, NaCl concentration and current was considered. It was observed that the four variables studied are significant for the process, with NaCl concentration and current being the most significant variables for free chlorine production. The maximum free chlorine production was obtained at a current of 2.33 A and NaCl concentrations in 0.96 mol dm−3. The application of the optimized conditions with simultaneous UV irradiation resulted in up to 83.1% Total Organic Carbon removal and 100% of colour removal over 180 min of electrolysis. The results indicate that a systematic (statistical) approach to the electrochemical treatment of pollutants can save time and reagents.

Experimental-design-guided approach for the removal of atrazine by sono-electrochemical-UV-chlorine techniques

ABSTRACT The aim of the present study was to investigate the electrochemical formation of free chlorine species (HOCl/ClO−) and their subsequent use for the degradation of the pesticide atrazine. Initially, the process of electrochemical-free chlorine production was investigated using a bench-scale electrochemical flow-cell. The most significant variables (electrolyte concentration ([NaCl]) and inter-electrode gap) of the process were obtained using a 23 factorial design and the optimum process conditions (1.73 mol L−1 and 0.56 cm) were determined by a central composite design. Following optimization of free chlorine production, three degradation techniques were investigated, individually and in combination, for atrazine degradation: electrochemical, photochemical and sonochemical. The method using the techniques in combination was denominated sono-photo-assisted electrochemical degradation. Constant current assays were performed and the sono-photo-assisted electrochemical process promoted more efficient removal of atrazine, achieving total organic carbon removal of ∼98% and removal of atrazine to levels below the detection limit (>99%) in under 30 min of treatment. Furthermore, the combination of three techniques displayed lower energy consumption, and phytotoxicity tests (Lactuca sativa) showed that there was no increase in toxicity.

COMPARAÇÃO ENTRE FUNCIONAIS DE DENSIDADE NO ESTUDO DE PROPRIEDADES ELETRÔNICAS DE DERIVADOS DA ARTEMISININA

The present paper demonstrates the application of functional GGA hybrids, with long-range corrections, for the calculation of the electronic properties of artemisinin and two of its derivatives - artemether e artesunate. Due to the relatively large amount of data obtained, the statistical method of Principal Component Analysis was employed. The functionals of the WB97 family are observed to be the most appropriate for the determining of reactivity indexes, which are the principal descriptors that, probably, are associated with the antimalarial and anticancer properties of this group of molecules. In addition, it was also observed that all the functionals obtained satisfactorily describe the geometric properties of the studied.

PRECIPITATION REACTION OF CLAVULANIC ACID: THERMODYNAMIC AND ELECTRONIC STUDY

In the present article the theoretical calculation of thermodynamic parameters for the two main precipitation agents, potassium 2-ethylhexanoate and t-octylamine, employed by the pharmaceutical industry to obtain potassium clavulanate for clinical use, is described. The results obtained using the standard thermochemistry calculation in the Gaussian package and by calculation of the reactivity indexes of the reagents and products are compared. The calculated thermodynamic parameters indicate that the reactivity indexes present a better correlation with the experimentally obtained percentage yield. In addition, a series of additional precipitation agents that are also used in industrial procedures to obtain potassium clavulanate for clinical use, were compared. This was done to verify if any present, a priori, better properties than potassium 2-ethylhexanoate or t-octylamine. The consistency of the reactivity indexes calculated clearly suggests that the methodology employed can be used to screen future precipitation agents for possible use in the production of potassium clavulanate.

Isolation and antimicrobial activity of Streptomyces tubercidicus against pathogenic bacteria and fungi

Streptomyces spp. produces many secondary metabolites, including antibiotics. The substances formation is coupled with the onset of development of the microorganism and the search of new substances is important. The aim of this work was to evaluate the bioactivity of endophytic Streptomyces tubercidicus isolated from Solanum lycocarpum St. Hill, a typical Brazilian tropical savannah tree to test its inhibitory capability against pathogenic bacteria and fungi. S. tubercidicus was cultivated in ISP2A and submitted to antibiosis test against S. aureus (ATCC 29213), P. aeruginosa (ATCC 27853), E. coli (ATCC 25922) and C. albicans (ATCC 10231). S. tubercidicus presented antibiosis against S. aureus (35 mm), E. coli (40 mm) and C. albicans (19 mm), but failed to inhibit P. aeruginosa. Purification of crude extract of S. tubercidicus with permeation in Sephadex L20 gel methanol revealed two compounds with bioactivity against S. aureus and E. coli.