title: Antimicrobial constituents of Gomphrena martiana and Gomphrena boliviana.
abstract: The antimicrobial activity of extracts and constituents of Gomphrena martiana and Gomphrena boliviana (Amaranthaceae) were determined in order to identify the compounds responsible for the folk-medicinal use of these plants. Each extract was evaluated against 20 microorganisms, including Gram-positive and Gram-negative bacteria, spore-forming Gram-positive bacteria, an acid-fast bacterium, a fungus and two yeasts. Fractionation of each petroleum ether (PE) extract yielded five 5,6,7-trisubstituted flavones that were separately tested showing high activity against M. phlei (minimum inhibitory concentration (MIC) 15, 20 and 75 micrograms/ml) approaching that of commercial bactericides. Other natural and synthetic flavonoids with diverse structures were also tested to define structure-activity relationships. Each EtOH extract was subsequently fractionated and monitored by bioassays leading to isorhamnetin 3-O-beta-robinobioside (MIC 50 micrograms/ml) in both instances. This glycoside is reported here for the first time in G. boliviana.
authors.affiliation: Departamento de Quimica Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
authors.forename: A B
authors.initials: AB
authors.lastname: Pomilio
authors.forename: C A
authors.initials: CA
authors.lastname: Buschi
authors.forename: C N
authors.initials: CN
authors.lastname: Tomes
authors.forename: A A
authors.initials: AA
authors.lastname: Viale
mesh_terms: D005419:Flavonoids / Q000494:pharmacology; D005658:Fungi / Q000187:drug effects*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry
chemical_list: D005419:Flavonoids; D010936:Plant Extracts