RESUMO
A π-conjugated porous organic polymer (BCzBz) was fabricated employing N,N'-bicarbazole and benzothiadiazole as molecular building units exhibiting broad visible light absorption. The photostable, water-dispersible, and cytocompatible BCzBz was demonstrated as an efficient probe for intracellular reactive oxygen species generation under photoirradiation.
Assuntos
Antineoplásicos/farmacologia , Carbazóis/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Polímeros/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Tiadiazóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/efeitos da radiação , Carbazóis/síntese química , Carbazóis/efeitos da radiação , Células HeLa , Humanos , Luz , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/efeitos da radiação , Polímeros/síntese química , Polímeros/efeitos da radiação , Porosidade , Tiadiazóis/síntese química , Tiadiazóis/efeitos da radiaçãoRESUMO
The antimicrobial potential of two bioflavonoids, i.e., 5,7-dihydroxy-4',6,8-trimethoxyflavone (1) and 5,6-dihydroxy-4',7,8-trimethoxyflavone (2), isolated from Limnophila heterophylla Benth. and L. indica (Linn.) Druce (Scrophulariaceae), respectively, were evaluated against the microbial strains Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Alternaria solani, and Candida albicans. Compounds 1 and 2 exhibited moderate but broad antimicrobial activities against both Gram-positive and Gram-negative bacteria and also against the fungal pathogens. Moreover, the mechanism of action of 1 and 2 on the cellular functions or structures of some of the microorganisms was studied. Compound 1 showed a bactericidal effect against E. coli and S. aureus (MICs of 200 and 250⠵g/ml, resp.), while compound 2 was found to effectively kill B. subtilis by cell lysis. The growth of A. solani and C. albicans was inhibited by compounds 1 and 2, respectively. The effects of the flavonoids on the cellular structures and the carbohydrate metabolic pathways were studied by scanning electron microscopy (SEM) of the treated cells and by assessing the specific activity of key enzymes of the pathways, respectively. At sublethal doses, they enhanced the activity of gluconeogenic fructose bisphosphatase, but decreased the activity of phosphofructokinase and isocitrate dehydrogenase, the key enzymes of the EmbdenMeyerhofParnas pathway and the tricarboxylic acid cycle, respectively.