title: Swietenia macrophylla extract promotes the ability of Caenorhabditis elegans to survive Pseudomonas aeruginosa infection.
abstract: BACKGROUND
  Swietenia macrophylla or commonly known as big leaf mahogany, has been traditionally used as an antibacterial and antifungal agent.
  
  
  OBJECTIVE
  The unwanted problem of antibiotic resistance in many bacterial species advocates the need for the discovery of the new anti-infective drugs. Here, we investigated the anti-infective properties of Swietenia macrophylla with an assay involving lethal infection of Caenorhabditis elegans with the opportunistic human pathogen Pseudomonas aeruginosa.
  
  
  METHODS
  Using a slow killing assay, Caenorhabditis elegans was challenged with an infective strain of Pseudomonas aeruginosa (PA14). The ability of Swietenia macrophylla seed ethyl acetate extract to promote the survival of infected worms was assessed by comparing the percentage of survival between extract treated and non-treated worm populations. The effect of Swietenia macrophylla towards PA14 growth, Caenorhabditis elegans feeding rate and degree of PA14 colonization in the worm gut was also evaluated. Lastly, using a fluorescent transgenic Caenorhabditis elegans strain and real time PCR, the effect of Swietenia macrophylla on the expression of lys-7, an immune response gene was also investigated.
  
  
  RESULTS
  Our results demonstrate the ability of Swietenia macrophylla seed ethyl acetate extract in rescuing Caenorhabditis elegans from fatal PA14 infection. Consequently, we showed that the extract promotes the survival without exhibiting any bactericidal effect or perturbation of Caenorhabditis elegans feeding rate. We also showed that Swietenia macrophylla was able to restore the initially repressed lys-7 level in PA14 infected Caenorhabditis elegans.
  
  
  CONCLUSIONS
  Swietenia macrophylla extract is able to enhance the ability of Caenorhabditis elegans to survive PA14 infection without directly killing the pathogen. We further showed that the extract boosted the expression of a gene pivotal for innate immunity in Caenorhabditis elegans. Collectively, these findings strongly suggest the presence of compounds within Swietenia macrophylla seed that either reduces Pseudomonas aeruginosa virulence and/or enhance host resistance.
authors.affiliation: Malaysian Institute of Pharmaceuticals and Nutraceuticals, Ministry of Science, Technology and Innovation, Penang, Malaysia.
authors.forename: Komalavali
authors.initials: K
authors.lastname: Dharmalingam
authors.forename: Boon-Khai
authors.initials: BK
authors.lastname: Tan
authors.forename: Muhd Zulkarnain
authors.initials: MZ
authors.lastname: Mahmud
authors.forename: Saiedatul Akmal Mohamed
authors.initials: SA
authors.lastname: Sedek
authors.forename: Mohamed Isa Abdul
authors.initials: MI
authors.lastname: Majid
authors.forename: Meng-Kiat
authors.initials: MK
authors.lastname: Kuah
authors.forename: Shaida Fariza
authors.initials: SF
authors.lastname: Sulaiman
authors.forename: Kheng Leong
authors.initials: KL
authors.lastname: Ooi
authors.forename: Nurzalina Abdul Karim
authors.initials: NA
authors.lastname: Khan
authors.forename: Tengku Sifzizul Tengku
authors.initials: TS
authors.lastname: Muhammad
authors.forename: Man-Wah
authors.initials: MW
authors.lastname: Tan
authors.forename: Alexander Chong
authors.initials: AC
authors.lastname: Shu-Chien
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D007113:Immunity, Innate / Q000187:drug effects / Q000235:genetics; D029582:Meliaceae / Q000737:chemistry; D008856:Microscopy, Fluorescence; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000276:immunology / Q000472:pathogenicity; D012639:Seeds; D012997:Solvents; D013997:Time Factors; D015854:Up-Regulation; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D029742:Caenorhabditis elegans Proteins; D010936:Plant Extracts; D012997:Solvents