RESUMO
Emodin reduction to emodin anthrone comprise one of three process steps involved in the hypericin synthesis, a powerful natural photosensitiser found in plants of the genus Hypericum. In this communication, an optimized protocol was established for emodin reduction enabling an efficient multigram preparation of emodin anthrone. A screening of reducing agent (SnCl2·2H2O and HClconc) under different reaction times was employed in micro-scale and monitored by electronic absorption spectroscopy technique. Data showed lower yields of emodin anthrone when some experimental conditions previously described in the literature were reproduce. However, using the optimized protocol for the emodin reduction these yields were overcoming, and a gram-scale supply experiment was reproducible for the preparation of 10 grams of emodin anthrone with excellent yield.
Assuntos
Emodina/análogos & derivados , Emodina/química , Hypericum/química , Perileno/análogos & derivados , Antracenos , Antraquinonas/química , Emodina/síntese química , Perileno/síntese química , Radiossensibilizantes/síntese química , Substâncias RedutorasRESUMO
BACKGROUND: Photodynamic therapy (PDT) has demonstrated promising results in the treatment of several clinical pathologies through the photochemical reaction caused by the combination of a photosensitizer and a light source. The objective of this study was to evaluate the antimicrobial effect of the combination of the photosensitizers (PSs) erythrosine/methylene blue activated by a white halogen light device on Streptococcus mutans biofilm. METHODS: Two separate experiments were conducted, the first using the PSs at the concentration of 100⯵M, and the second 250⯵M. The PSs were tested on S. mutans biofilms cultured for 24â¯h in isolation, in combination, with and without light activation for 2â¯min fractionated in 4 periods of 30â¯s. After treatment, biofilms were diluted and plated on BHI medium and incubated for 24â¯h for colony forming units (CFU) counting. The results (log10) were analyzed with ANOVA followed by Tukey test (pâ¯<â¯0.05). RESULTS: The erythrosine/methylene blue combination activated by white halogen light at 100 and 250⯵M, and erythrosine at 250⯵M, methylene blue at 250⯵M presented significantly reduced cell counts (3.2 log10, 5.3 log10, 4.5 log10, 4.3 log10, respectively) when compared to controls (pâ¯<â¯0.05). CONCLUSION: PDT with the combination of erythrosine/methylene blue demonstrated better results that the PSs in isolation regardless of the concentration. The use of this combination at the concentration of 250⯵M shows promise as an antibacterial treatment for carious lesions and should be further assessed.