title: Photodynamic effect of hypericin on the microorganisms and primary human fibroblasts.
abstract: BACKGROUND
  Hypericin (HYP) is a natural photosensitizer considered for the new generation of photodynamic therapy (PDT) drugs. The aim of this study was to evaluate the in vitro bactericidal effect of HYP-PDT on four bacterial species, assessing its photocytotoxicity to primary human fibroblasts to determine possible side effects.
  
  
  METHODS
  Effect of photosensitizer concentration (0.1, 0.3, 0.6, and 1 μg/ml) and light irradiation time (3, 5, 10 min) on photodynamic inactivation of microorganisms and primary human fibroblasts was investigated.
  
  
  RESULTS
  A 6.3 log killing was obtained for Staphylococcus aureus (ATCC 25923) treated with 1 μg/ml at 48 J/cm². For this set of PDT parameters, Enterococcus faecalis (ATCC 11700) showed 6.5 log killing, Escherichia coli (ATCC 25922) 6.2 log killing, and Pseudomonas aeruginosa (ATCC 27853) 0.7 log killing. Fibroblasts can be preserved by keeping the HYP concentration below 0.6 μg/ml and the light dose below 48 J/cm².
  
  
  CONCLUSIONS
  S. aureus, E. faecalis, and E. coli appear to be suitable for treatment with HYP-PDT without significant damage to fibroblasts.
authors.affiliation: Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran. kashefn@khayam.ut.ac.ir
authors.forename: Nasim
authors.initials: N
authors.lastname: Kashef
authors.forename: Yasaman Sadat
authors.initials: YS
authors.lastname: Borghei
authors.forename: Gholamreza Esmaeeli
authors.initials: GE
authors.lastname: Djavid
mesh_terms: D000873:Anthracenes; D018407:Bacterial Physiological Phenomena / Q000187:drug effects* / Q000528:radiation effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects; D006801:Humans; D008029:Lighting / Q000379:methods*; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D010569:Perylene / Q000008:administration & dosage / Q000031:analogs & derivatives*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage
chemical_list: D000873:Anthracenes; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin