title: Photodynamic antimicrobial effects of bis-indole alkaloid indigo from Indigofera truxillensis Kunth (Leguminosae).
abstract: Multidrug-resistant microbial infections represent an exponentially growing problem affecting communities worldwide. Photodynamic therapy is a promising treatment based on the combination of light, oxygen, and a photosensitizer that leads to reactive oxygen species production, such as superoxide (type I mechanism) and singlet oxygen (type II mechanism) that cause massive oxidative damage and consequently the host cell death. Indigofera genus has gained considerable interest due its mutagenic, cytotoxic, and genotoxic activity. Therefore, this study was undertaken to investigate the effect of crude extracts, alkaloidal fraction, and isolated substance derived from Indigofera truxillensis in photodynamic antimicrobial chemotherapy on the viability of bacteria and yeast and evaluation of mechanisms involved. Our results showed that all samples resulted in microbial photoactivation in subinhibitory concentration, with indigo alkaloid presenting a predominant photodynamic action through type I mechanism. The use of CaCl2 and MgCl2 as cell permeabilizing additives also increased gram-negative bacteria susceptibility to indigo.
authors.affiliation: Instituto de Biologia, Departamento de Biologia Vegetal, PPG BTPB e PPG BV, Universidade Estadual de Campinas (UNICAMP), 13083-970, Campinas, SP, Brazil, nathilu@gmail.com.
authors.forename: Nathalia Luiza
authors.initials: NL
authors.lastname: Andreazza
authors.forename: Caroline C
authors.initials: CC
authors.lastname: de Lourenço
authors.forename: Maria Élida Alves
authors.initials: MÉ
authors.lastname: Stefanello
authors.forename: Teresa Dib Zambon
authors.initials: TD
authors.lastname: Atvars
authors.forename: Marcos José
authors.initials: MJ
authors.lastname: Salvador
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D007203:Indigo Carmine / Q000494:pharmacology*; D029883:Indigofera / Q000737:chemistry; D054023:Lasers, Semiconductor; D008826:Microbial Sensitivity Tests; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology*; D011514:Proteus vulgaris / Q000187:drug effects; D026082:Singlet Oxygen / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D017319:Photosensitizing Agents; D026082:Singlet Oxygen; D007203:Indigo Carmine