title: Photobiological characteristics of chlorophyll a derivatives as microbial PDT agents.
abstract: Chlorin-e6 (chl-e6) and a hydrogenated derivative (chl-e6H) were semi-synthesized, and their photophysical properties and photodynamic activity against Escherichia coli, Staphylococcus aureus and Candida albicans evaluated. Methyl pheophorbide-a (Mepheo-a) was obtained from S. maxima using methanolic extraction with acid catalysis (CH3OH–H2SO4). Chlorin-e6 was prepared from Mepheo-a by basic hydrolysis with H2O–acetone and NaOH. Hydrogenated Chlorin-e6 was synthesized by a similar procedure starting from the hydrogenated methyl pheophorbide-a (Mepheo-aH). Photophysical studies were performed in order to determine the singlet oxygen quantum yield of chl-e6H which is higher than that of chl-e6. The microorganism inactivation of chl-e6 and chl-e6H was investigated at two concentrations and three fluence levels. Both chl-e6 and chl-e6H showed microorganism inactivation against Gram-positive bacteria and a fungus.
authors.affiliation: Instituto de Física de São Carlos - Universidade de São Paulo, Av: Trabalhador São Carlense, 400, São Carlos, São Paulo 13566-590, Brazil. cristina@ifsc.usp.br.
authors.forename: Marciana P
authors.initials: MP
authors.lastname: Uliana
authors.forename: Layla
authors.initials: L
authors.lastname: Pires
authors.forename: Sebastião
authors.initials: S
authors.lastname: Pratavieira
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Brocksom
authors.forename: Kleber T
authors.initials: KT
authors.lastname: de Oliveira
authors.forename: Vanderlei S
authors.initials: VS
authors.lastname: Bagnato
authors.forename: Cristina
authors.initials: C
authors.lastname: Kurachi
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology* / Q000528:radiation effects; D002176:Candida albicans / Q000187:drug effects; D002734:Chlorophyll / Q000737:chemistry / Q000494:pharmacology* / Q000528:radiation effects; D000077194:Chlorophyll A; D002735:Chlorophyllides; D004926:Escherichia coli / Q000187:drug effects; D006865:Hydrogenation; D015394:Molecular Structure; D038761:Photobleaching; D055668:Photochemical Processes; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology / Q000528:radiation effects; D011166:Porphyrins / Q000737:chemistry / Q000494:pharmacology / Q000528:radiation effects; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D002735:Chlorophyllides; D017319:Photosensitizing Agents; D011166:Porphyrins; D002734:Chlorophyll; C062985:phytochlorin; D000077194:Chlorophyll A