Recebido em 18/5/09; aceito em 4/9/09; publicado na web em 22/2/10 TETRACYCLINES AND GLYCYLCYCLINES: AN OVERVIEW. Tetracyclines exhibits activity to a broad range of Gram-negative and Gram-positive bacteria and this fact allied to the low toxicity, low cost, and the advantage of administration by oral route led to their indiscriminate use, which caused the appearance of bacterial resistance to these agents, wich has restricted its clinical utility, though new applications have emerged. On the other hand, the glycylcyclines, semi-synthetic products are similar to tetracyclines, which are active against many bacteria resistant to tetracycline and other classes of antibiotics. The purpose of this paper is to give an overview of this important class of antibiotics focusing on its coordination chemistry and possible applications.Keywords: tetracyclines; glycylcyclines; antibacterial activity. INTRODUÇÃOA descoberta do primeiro membro da família das tetraciclinas em 1945 por Benjamin Duggar, a clortetraciclina, que é um produto da fermentação natural de uma bactéria do solo, Streptomyces aureofaciens, provocou uma corrida na pesquisa e obtenção de novas tetraciclinas com grande sucesso. Assim, de 1950 a 1970, vários membros da família das tetraciclinas haviam sido desenvolvidos, uns como produtos naturais, outros como produtos semissintéticos e, neste mesmo período, as tetraciclinas figuraram entre os antibióticos mais usados nos Estados Unidos. 1-3Após a descoberta da minociclina em 1972, um longo tempo se passou sem que novas tetraciclinas fossem descobertas até que, no ano de 1993, as glicilciclinas, foram sintetizadas. As glicilciclinas são produtos semissintéticos análogos às tetraciclinas, que são ativos contra inúmeras bactérias resistentes às tetraciclinas e a outras classes de antibióticos. 4 Em 2005, o composto denominado tigeciclina (tygacil TM ), uma glicilciclina derivada da minociclina, que possui um grupo glicilamido na posição C9, foi aprovado para uso clínico pela FDA e, recentemente, o composto denominado PTK-0796, um derivado semissintético da minociclina, tem chamado a atenção, pois entrou em fase I de testes clínicos. 5,6 Tetraciclinas possuem diversas propriedades favoráveis, tais como amplo espectro de ação, baixa toxicidade, baixo custo, e podem ser, na maioria dos casos, administradas por via oral.1,2 Devido a essas propriedades, tetraciclinas em geral têm sido utilizadas indiscriminadamente, o que tem levado ao aparecimento de resistência em um grupo variado de bactérias, principalmente às tetraciclinas de primeira geração, descobertas no período compreendido entre 1950 e 1970, e isto provocou e tem provocado restrições na utilidade clínica destes compostos.3 No entanto, tetraciclinas ainda são bastante úteis na clínica médica e têm sido usadas no tratamento de diversos tipos de infecção.7-9 Além do uso em humanos, tetraciclinas são utilizadas na terapia animal para tratar infecções e promover o crescimento.7 Além disso, tigeciclina e minociclina têm sido indicadas no tratamento de MRSA (Stap...

In this report, we demonstrate how UV-light exposure can enhance DNA cleavage promoted by two copper(II) complexes of tetracyclines and 1,10-phenanthroline about 40 times in comparison to nonirradiated conditions. In addition, new aspects regarding their DNA binding properties, as well as the mechanism of the cleavage reaction, were also investigated.

A cosmetic product consists of natural or synthetic substances, the purpose of which is to wash, scent, correct and protect the various parts of the human body. Human skin has pores that connect to the oil glands, which produce sebum, an oily liquid that carries dead cells through the hair follicles to the surface of the epidermis, causing the appearance of skin lesions and the growth of microorganisms. In the present work, two antimicrobial soaps were formulated in solid and liquid form using essential oil of Schinus terebinthifolius and Piper nigrun, analysed and compared with other antimicrobial soaps available on the market. In addition, the microbiological safety of the products developed was tested, according to ANVISA criteria. All products developed in this work have microbiological safety, but the best inhibitory results regarding the growth of the microorganisms Staphylococcus aureus and Escherichia coli were obtained with the soaps in liquid form.

Abstract.A new complex of palladium was isolated with 2-furoic hydrazide (FH) and characterized by spectroscopic methods. The results show that the ligand is coordinated to palladium by the basic nitrogen of NH 2 group and has a general structure of type cis-[Pd(FH) 2 Cl 2 ]. The structure of palladium(II) complex was optimized and theoretical data show good agreement with the experimental results. The cytotoxic activity was evaluated in a chronic myelogenous leukemia cell line, which revealed that the compound is less active than cisplatin or carboplatin. At 300 g mL −1 , the complex presented antimicrobial activity more efficient than ampicillin, chloranfenicol and kanamicyn. (doi: 10.5562/cca2151)

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The use of chicken eggshells and ferrous metal waste were evaluated as feedstock for the synthesis of Ca2Fe2O5 perovskite. The solid Ca2Fe2O5 obtained was applied as heterogeneous catalyst in the transesterification reaction of soybean oil with methanol for biodiesel production. The calcium ferrite (Ca2Fe2O5) obtained from waste materials was formed at temperatures above 898 K and its basic force was very similar to that one presented in the same structure obtained using high-purity reagents. The formation of the Ca2Fe2O5/CaO system occurred for both catalysts at higher temperatures. The catalysts Ca2Fe2O5lab and Ca2Fe2O5res presented the same basic strength, 0.469 and 0.473 mmol/g, respectively. This fact indicates that both cata- lysts have similar structures even though they were prepared with very different origins of reagents. Besides that, the residual Ca2Fe2O5 perovskite showed a good catalytic performance in the transesterification reaction. The transesterification reaction led to yields of biodiesel greater than 80 %, at 333 K, methanol to oil molar ratio of 3:1 and 10 h of batch reaction.

The search for alternative methods to replace sulfur in the sugarcane juice clarification step has been increasing. The sulfur dioxide (SO2) produced in the combustion of sulfur is toxic and can cause environmental problems and risks to human health. This work aimed to analyze scientific articles on alternative methods to sulfitation published between 2011 and 2021, based on searches in the Portal de Periódicos Capes, Scielo and Web of Science. Among the 434 researched scientific articles, 296 were repeated and 138 were unique, of which 94 had the text available in full and 44, unavailable. Thirty were selected to compose this review, for reporting on alternative methods of clarification: carbonation (4), ozonation (6), peroxidation (5), microfiltration (6), natural flocculants (5), bagasse fly ash (1), centrifugation (1), lime, bentonite and activated carbon (1), lime saccharate, ammonium hydroxide (NH4OH) and sodium hydroxide (NaOH) (1). All methods proved to be effective and less polluting, in addition to reducing the consumption of chemical reagents.

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