Antimicrobial Photodynamic Therapy and Hypericin: A Potential Treatment Against Escherichia Coli

Herein we analyzed the efficiency of hypericin as a photosensitizer for inhibition of Escherichia coli. We analyzed the bacterial uptake of hypericin by indirect studies using flow cytometry and investigated the effects of aPDT with hypericin on the microbial growth and viability. The results showed that the treatment with 10 μM hypericin (Hyp), 5 minutes of incubation time and light dose of 38.4 J/cm2, was responsible for an inhibition of more than 50%, demonstrating that this combination was effective against E. coli. This condition was used for the kinetic tests, which showed a bacteriostatic mechanism, with a gradual recovering of bacterial growth after 4 hours. With our results, it can be inferred that Hyp is an efficient photosensitizer in aPDT and it is promise to be used.