title: Immune-stimulating properties of 80% methanolic extract of Ludwigia octovalvis against Shiga toxin-producing E. coli O157:H7 in Balb/c mice following experimental infection.
abstract: BACKGROUND
  Ludwigia octovalvis is an aquatic plant widely distributed throughout the tropical and sub-tropical regions. It is commonly consumed as a health drink and traditionally used for treating various ailments such as dysentery, diarrhea, diabetes, nephritisn and headache. No information is available on its in vivo antibacterial activity against an important foodborne pathogen, Shiga toxin producing Escherichia coli O157:H7.
  
  
  METHODS
  Male Balb/c mice were orally administered with the extract at doses of 200 or 400mg/kg body weight for one week before the infection with E. coli O157:H7 and continued for 14 consecutive days after infection. Serum antibody (IgA, IgG and IgM) levels were quantified at days 7 and 14 post-challenge by an ADVIA(®) 2400 Clinical Chemistry Auto Analyzer. Nitroblue tetrazolium (NBT) and Ceruloplasmin, as nonspecific immune parameters, were determined enzymatically.
  
  
  RESULTS
  A significant increase (p<0.05) in IgA serum level was indicated on the 7th day post-challenge with the pathogen in the experimental group received 400mg/kg of the extract in comparison with other groups. Total IgA serum levels on day 7 post-challenge in groups of PBS negative control, E. coli O157:H7 positive control, E. coli O157:H7+200mg/kg extract group and E. coli O157:H7+400mg/kg extract group were 709.4 ± 149.6, 1655.8 ± 139.7, 1728.6 ± 64.3 and 1971.4 ± 135.6 µg/ml, respectively. Serum IgG and IgM did not significantly change among different groups. The extract administered orally to infected Balb/c mice did not affect the NBT as well as ceruloplasmin levels.
  
  
  CONCLUSIONS
  The extract of L. octovalvis contains biologically active principles which increased systemic immune response to E. coli O157:H7 via potentiating the synthesis of IgA antibodies.
authors.affiliation: Department of Biology, College of Education for Pure Sciences, AL-Anbar University, 00964 Ramadi, Iraq. Electronic address: h_alsalmany2006@yahoo.com.
authors.forename: Haidar
authors.initials: H
authors.lastname: Kadum Yakob
authors.affiliation: School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
authors.forename: Abd
authors.initials: A
authors.lastname: Manaf Uyub
authors.affiliation: School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
authors.forename: Shaida
authors.initials: S
authors.lastname: Fariza Sulaiman
mesh_terms: D000818:Animals; D004927:Escherichia coli Infections / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D056747:Immunomodulation / Q000187:drug effects*; D007928:Lethal Dose 50; D008297:Male; D000432:Methanol / Q000737:chemistry; D051379:Mice; D029594:Onagraceae / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology*; D022603:Shiga Toxins / Q000096:biosynthesis*
chemical_list: D010936:Plant Extracts; D022603:Shiga Toxins; D000432:Methanol
keywords: Anti-E. coli O157:H7; Immune response; Ludwigia octovalvis; in vivo