title: Effects of Rhodomyrtus tomentosa Extract on Killing Activity of Human Neutrophils and Membrane Integrity of Enterohaemorrhagic Escherichia coli O157:H7.
abstract: Enterohaemorrhagic Escherichia coli (E. coli) O157:H7 is one of the most virulent causative agents of foodborne disease. Use of antibiotics for the treatment against E. coli O157:H7 infection leads to hemolytic uremic syndrome. The present study evaluated the potential of ethanolic leaf extract of a medicinal plant, Rhodomyrtus tomentosa in enhancing the killing activity of human neutrophils against E. coli O157:H7. In addition, the effects of the extract on membrane permeability of the organisms were studied. In the killing assay, percentage survival of the bacterial cells after being exposed to human neutrophils in the presence of various concentrations of the extract were determined. At 45 min, percentage survival of E. coli O157:H7 and E. coli ATCC 25922 after treated with neutrophils in the presence of the extract at 125-250 µg/mL was 58.48%-50.28% and 69.13%-35.35%, respectively. Furthermore, upon treatment with R. tomentosa at 250 µg/mL uptake of crystal violet by E. coli O157:H7 and E. coli ATCC 25922 was increased to 40.07% and 36.16%, respectively. Therefore, it is suggested that the extract exhibited dual effects as immunostimulant and membrane permeabilizing agent perhaps resulted in enhancing the killing activity of neutrophils against the organisms.
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. bebegamalar@gmail.com.|Excellent Research Laboratory on Natural products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. bebegamalar@gmail.com.
authors.forename: Jutharat
authors.initials: J
authors.lastname: Hmoteh
authors.affiliation: Excellent Research Laboratory on Natural products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. syed_musthafa@rediffmail.com.
authors.forename: Khadar
authors.initials: K
authors.lastname: Syed Musthafa
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. rattanaruji.p@psu.ac.th.
authors.forename: Rattanaruji
authors.initials: R
authors.lastname: Pomwised
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. supayang.v@psu.ac.th.|Excellent Research Laboratory on Natural products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. supayang.v@psu.ac.th.
authors.forename: Supayang Piyawan
authors.initials: SP
authors.lastname: Voravuthikunchai
mesh_terms: D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D019453:Escherichia coli O157 / Q000276:immunology*; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology; D027822:Myrtaceae / Q000737:chemistry*; D009504:Neutrophils / Q000187:drug effects* / Q000276:immunology* / Q000382:microbiology; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry
chemical_list: D007155:Immunologic Factors; D010936:Plant Extracts
keywords: Escherichia coli O157:H7; Rhodomyrtus tomentosa; human neutrophils; immunomodulatory activity; membrane integrity