title: Nanoemulsions Containing a Coumarin-Rich Extract from Pterocaulon balansae (Asteraceae) for the Treatment of Ocular Acanthamoeba Keratitis.
abstract: This study describes the incorporation of a coumarin-rich extract from Pterocaulon balansae into nanoemulsions intended for the local treatment of ocular keratitis caused by Acanthamoeba. The n-hexane dewaxed extract of P. balansae was characterized by HPLC/PDA and UPLC/MS. The presence of four major coumarins was detected, where 5-methoxy-6,7-methylenedioxycoumarin was selected as a chemical marker. This extract was then incorporated into nanoemulsions composed of medium chain triglycerides and egg-lecithin, through spontaneous emulsification. Such a procedure yielded the formation of monodisperse nanoemulsions in a sub-300-nm range, regardless of the amount of extract incorporated (1.0-5.0 mg/mL). The amoebicidal activity against Acanthamoeba castellanii was both dose-dependent and incubation time-dependent. A reduction of 95% of trophozoite viability was detected after 24 h of incubation with a nanoemulsion at 1.25 mg/mL of coumarins, being a similar effect detected for chlorhexidine. These results suggest a potential of the formulations developed in this study as a new strategy for the treatment of ocular keratitis caused by Acanthamoeba.
authors.affiliation: Faculty of Pharmacy, Federal University of Rio Grande do Sul, 2752 Ipiranga, 90610-000, Porto Alegre, Brazil.
authors.forename: Lua Ferreira
authors.initials: LF
authors.lastname: Panatieri
authors.affiliation: Faculty of Pharmacy, Federal University of Rio Grande do Sul, 2752 Ipiranga, 90610-000, Porto Alegre, Brazil.
authors.forename: Nathalya Tesch
authors.initials: NT
authors.lastname: Brazil
authors.affiliation: Faculty of Pharmacy, Federal University of Rio Grande do Sul, 2752 Ipiranga, 90610-000, Porto Alegre, Brazil.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Faber
authors.affiliation: Faculty of Pharmacy, Federal University of Rio Grande do Sul, 2752 Ipiranga, 90610-000, Porto Alegre, Brazil.
authors.forename: Bruna
authors.initials: B
authors.lastname: Medeiros-Neves
authors.affiliation: Faculty of Pharmacy, Federal University of Rio Grande do Sul, 2752 Ipiranga, 90610-000, Porto Alegre, Brazil.
authors.forename: Gilsane Lino
authors.initials: GL
authors.lastname: von Poser
authors.affiliation: Institute of Basic Health Sciences, 500 Sarmento Leite, 90050-170, Porto Alegre, Brazil.
authors.forename: Marilise Brittes
authors.initials: MB
authors.lastname: Rott
authors.affiliation: Faculty of Pharmacy, Federal University of Rio Grande do Sul, 2752 Ipiranga, 90610-000, Porto Alegre, Brazil.
authors.forename: Giovanni Konat
authors.initials: GK
authors.lastname: Zorzi
authors.affiliation: Faculty of Pharmacy, Federal University of Rio Grande do Sul, 2752 Ipiranga, 90610-000, Porto Alegre, Brazil. helder.teixeira@ufrgs.br.
authors.forename: Helder Ferreira
authors.initials: HF
authors.lastname: Teixeira
mesh_terms: D015823:Acanthamoeba Keratitis / Q000188:drug therapy* / Q000382:microbiology; D048248:Acanthamoeba castellanii / Q000187:drug effects; D019659:Asteraceae / Q000737:chemistry*; D052117:Benzodioxoles / Q000737:chemistry; D003374:Coumarins / Q000737:chemistry* / Q000494:pharmacology*; D004655:Emulsions / Q000737:chemistry* / Q000494:pharmacology*; D006586:Hexanes / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology
chemical_list: C580931:5-methoxy-6,7-methylenedioxycoumarin; D052117:Benzodioxoles; D003374:Coumarins; D004655:Emulsions; D006586:Hexanes; D010936:Plant Extracts; C026385:n-hexane; C030123:coumarin
keywords: Acanthamoeba; Pterocaulon balansae; coumarins; nanoemulsion; ocular keratitis