Antimicrobial effect of photodynamic therapy using erythrosine/methylene blue combination on Streptococcus mutans biofilm.

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 μM, and the second 250 μM.

Optimized protocol for multigram preparation of emodin anthrone, a precursor in the hypericin synthesis.

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 (SnCl·2HO and HCl) under different reaction times was employed in micro-scale and monitored by electronic absorption spectroscopy technique.