title: Bacterial resistance modifying tetrasaccharide agents from Ipomoea murucoides.
abstract: As part of an ongoing project to identify oligosaccharides which modulate bacterial multidrug resistance, the CHCl(3)-soluble extract from flowers of a Mexican arborescent morning glory, Ipomoea murucoides, through preparative-scale recycling HPLC, yielded five lipophilic tetrasaccharide inhibitors of Staphylococcusaureus multidrug efflux pumps, murucoidins XII-XVI (1-5). The macrocyclic lactone-type structures for these linear hetero-tetraglycoside derivatives of jalapinolic acid were established by spectroscopic methods. These compounds were tested for in vitro antibacterial and resistance modifying activity against strains of Staphylococcus aureus possessing multidrug resistance efflux mechanisms. Only murucoidin XIV (3) displayed antimicrobial activity against SA-1199B (MIC 32microg/ml), a norfloxacin-resistant strain that over-expresses the NorA MDR efflux pump. The four microbiologically inactive (MIC>512microg/ml) tetrasaccharides increased norfloxacin susceptibility of this strain by 4-fold (8microg/ml from 32microg/ml) at concentrations of 25microg/ml, while murucoidin XIV (3) exerted the same potentiation effect at a concentration of 5microg/ml.
authors.affiliation: Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510DF, Mexico.
authors.forename: Lilia
authors.initials: L
authors.lastname: Chérigo
authors.forename: Rogelio
authors.initials: R
authors.lastname: Pereda-Miranda
authors.forename: Simon
authors.initials: S
authors.lastname: Gibbons
mesh_terms: D002240:Carbohydrate Sequence; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D027741:Ipomoea / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D050296:Microbial Viability / Q000187:drug effects; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D009844:Oligosaccharides