Synthesis and reactions of 2, 9-Bis[4-N, N-dimethyl phenyl]- 5, 12-N, N'-Bis[aryl]-1, 5, 8, 12-tetraazatetracyclo-[6, 6, 0, 3, 70, 10, 140]tetradecane-4, 6, 11, 13-tetraones and their screening for biological activity.

Criss-cross cycloaddition reaction of aldazines 1 and 2 with N-arylmaleimides 3a-e represents an efficient method to obtain good yields of 2, 9-bis[aryl]-N, N'-5, 12-bis[aryl]-1, 5, 8, 12- tetraazatetracycl [6, 6, 0, 3, 70, 10, 140]tetradecane-4, 6, 11, 13-tetraones 4a-eand bromin-ated 5a-d, respectively, in solvent-free phase. Some of synthesized compounds were directed towards reduction, hydrolysis and dehydrogenation reactions to afford the expected compounds 6a-e, 7b, d, e and 8a, e respectively. The structure of the new synthesized compounds was confirmed spectrally [by IR, 1H NMR and Mass spectroscopy] and by elemental analysis. Some of the synthesized compounds were exhibit activity against some of bacterial and/ or fungal species.

Avaliação da atividade antibacteriana da microalga Spirulina platensis / Assessment of the antibacterial activity of microalgae Spirulina platensis

Infecções são agravadas pelo aumento da resistência dos microrganismos a substâncias antimicrobianas. A necessidade de descoberta de novos medicamentos em decorrência desta resistência microbiana tem impulsionado o desenvolvimento de novas pesquisas. A Spirulina platensis, reconhecida pelas suas propriedades nutricionais, possui alta quantidade de compostos fenólicos, os quais podem apresentar também propriedades antimicrobianas. Objetivou-se cultivar a microalga Spirulina platensis, avaliar a produção de compostos fenólicos pela mesma, caracterizar a possível atividade antimicrobiana dos fenóis frente a Escherichia coli ATCC 25922, a Pseudomas aeruginosa ATCC 27853 e o Staphylococcus aureus ATCC 6538P e determinar a concentração inibitória mínima do extrato fenólico frente às bactérias citadas. Os resultados demonstraram que elevadas concentrações de nitrato de sódio (4g/L) no meio de cultivo não aumentaram a produção de compostos fenólicos. A microalga cultivada com 2 g/L de nitrato de sódio apresentou 2,13 mg/g de compostos fenólicos, sendo que os extratos apresentaram atividade antibacteriana contra o S. aureus, bactéria Grampositiva, com halo de inibição de 22 mm e 19 mm e concentração inibitória mínima de 47,46 mg/mL, indicando sua importância como potencial inibidor de S. aureus.

Bacterial infections are aggravated by the increasing resistance of microorganisms to antimicrobial substances. The need to discover new medicines to evade microbial resistance is the driving force behind much new research. The microalga Spirulina platensis, recognized for its nutritional properties, has a high content of phenolic compounds, which can provide antimicrobial properties. The objective of this study was to establish a culture of Spirulina platensis, estimate the production of phenolic compounds by this microalga, characterize the antimicrobial activity of the phenolics against microorganisms such as Escherichia coli ATCC 25922, Pseudomas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 6538P and determine the minimum inhibitory concentration (MIC) of the phenolic extract for these bacteria. It was found that adding high concentrations of sodium nitrate (4 g/L) to the medium did not increase the production of phenolic compounds. The microalgae grown with 2 g/L sodium nitrate produced 2.13 mg/g of phenolic compounds, and the extracts showed antibacterial activity against S. aureus, a Gram-positive bacterium, with inhibition haloes of 22 mm and 19 mm and a MIC of 47.46 mg/ mL, indicating its importance as a potential S. aureus inhibitor.