title: Antibacterial Activity of Alkaloid Fractions from Berberis microphylla G. Forst and Study of Synergism with Ampicillin and Cephalothin.
abstract: Berberis microphylla is a native plant that grows in Patagonia and is commonly used by aboriginal ethnic groups in traditional medicine as an antiseptic for different diseases. The present study evaluated the antibacterial and synergistic activity of alkaloid extracts of B. microphylla leaves, stems and roots used either individually or in combination with antibiotics against Gram-positive and Gram-negative bacteria. The in vitro antibacterial activities of leaf, stem and root alkaloid extracts had significant activity only against Gram-positive bacteria. Disc diffusion tests demonstrated that the root extract showed similar activity against B. cereus and S. epidermidis compared to commercial antibiotics, namely ampicillin and cephalothin, and pure berberine, the principal component of the alkaloid extracts, was found to be active only against S. aureus and S. epidermidis with similar activity to that of the root extract. The minimum inhibitory concentrations (MICs) of the alkaloid extracts ranged from 333 to 83 μg/mL, whereas minimum bactericidal concentrations (MBCs) varied from 717 to 167 μg/mL. In addition, synergistic or indifferent effects between the alkaloid extracts and antibiotics against bacterial strains were confirmed.
authors.affiliation: Laboratorio de Productos Naturales, Instituto de la Patagonia, Universidad de Magallanes, Punta Arenas 6210427, Chile. Loreto.manosalva@umag.cl.
authors.forename: Loreto
authors.initials: L
authors.lastname: Manosalva
authors.affiliation: Laboratorio de Química Ecológica, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco 4811230, Chile. ana.mutis@ufrontera.cl.
authors.forename: Ana
authors.initials: A
authors.lastname: Mutis
authors.affiliation: Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40, Correo 33, Santiago 9170022, Chile. alejandro.urzua@usach.cl.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Urzúa
authors.affiliation: Laboratorio de Productos Naturales, Instituto de la Patagonia, Universidad de Magallanes, Punta Arenas 6210427, Chile. victor.fajardo@umag.cl.
authors.forename: Victor
authors.initials: V
authors.lastname: Fajardo
authors.affiliation: Laboratorio de Química Ecológica, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco 4811230, Chile. andres.quiroz@ufrontera.cl.
authors.forename: Andrés
authors.initials: A
authors.lastname: Quiroz
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D028142:Berberis / Q000737:chemistry*; D002512:Cephalothin / Q000494:pharmacology*; D004357:Drug Synergism; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D001600:Berberine Alkaloids; D010936:Plant Extracts; D000667:Ampicillin; D002512:Cephalothin
keywords: Berberis microphylla; alkaloid extracts; antibacterial activity; synergism