title: Iridoids from Canthium subcordatum iso-butanol fraction with potent biological activities.
abstract: BACKGROUND
  The continuous emergence of multi-drug-resistant bacteria drastically reduces the efficacy of antibiotic armory and, consequently, increases the frequency of therapeutic failure. The discovery of new antibacterial drugs is an urgent need. The present study reports the antibacterial and antioxidant activities of the methanol extract, fractions and iridoids from Canthium subcordatum, a plant traditionally used as antidiabetic, anti-inflammatory, and antimicrobial.
  
  
  METHODS
  Broth microdilution assay was used to determine minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of extracts and iridoids against Staphylococcus aureus, Vibrio cholerae and Shigella flexneri. Antioxidant activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and gallic acid equivalent antioxidant capacity (GAEAC) assays. The samples were also tested for their cytotoxicity against human red blood cells (RBC).
  
  
  RESULTS
  The methanol extract, hexane, ethyl acetate and iso-butanol fractions from C. subcordatum fruits displayed different degrees of antioxidant (EC50= 62.83-70.17 μg/ml; GAEAC = 45.63-58.23 μg/ml) and antibacterial (MIC = 128-512 μg/ml) activities. Canthiumoside 1(1) and linearin (7) were the most active antioxidant (EC50= 1.12-2.03 μg/ml; GAEAC = 79.82-92.35 μg/ml) and antibacterial (MIC = 8-64 μg/ml) compounds while the most sensitive bacterium was Staphylococcus aureus. The tested samples were non-toxic to normal cells.
  
  
  CONCLUSIONS
  Our results demonstrated that compounds 1 and 7 were potent antibacterial agents and DPPH/ABTS·+radical scavengers, so they warrant further investigation.
authors.affiliation: Department of Chemistry, Laboratory of Environmental and Applied Chemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Christelle
authors.initials: C
authors.lastname: Joubouhi
authors.affiliation: Department of Biochemistry, Laboratory of Microbiology and Antimicrobial Substances, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon. jtamokou@yahoo.fr.
authors.forename: Jean-de-Dieu
authors.initials: JD
authors.lastname: Tamokou
authors.affiliation: Department of Chemistry, Laboratory of Environmental and Applied Chemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon. dngnokam@yahoo.fr.
authors.forename: David
authors.initials: D
authors.lastname: Ngnokam
authors.affiliation: Groupe Isolement et Structure, Institut de Chimie Moléculaire de Reims (ICMR), CNRS UMR 7312, Bat. 18 BP.1039, 51687, Reims cedex 2, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Voutquenne-Nazabadioko
authors.affiliation: Department of Biochemistry, Laboratory of Microbiology and Antimicrobial Substances, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Jules-Roger
authors.initials: JR
authors.lastname: Kuiate
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001773:Blood Cells / Q000187:drug effects; D005638:Fruit / Q000737:chemistry; D053878:Hemolytic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D039823:Iridoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D019666:Rubiaceae / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D053878:Hemolytic Agents; D039823:Iridoids; D010936:Plant Extracts
keywords: Antimicrobial; Antioxidant; Canthium subcordatum; Fruit extracts; Iridoids; Phytochemical analysis; Rubiaceae