title: Kaffir lime leaves extract inhibits biofilm formation by Streptococcus mutans.
abstract: OBJECTIVE
  Although kaffir lime has been reported to exhibit antioxidant and antileukemic activity, little is known about the antimicrobial effect of kaffir lime extract. Because Streptococcus mutans has been known to cause biofilm formation, it has been considered the most important causative pathogen of dental caries. Thus, the effective control of its effects on the oral biofilm is the key to the prevention of dental caries. The aims of the present study were to investigate the effect of kaffir lime leaves extract on biofilm formation and its antibacterial activity on S. mutans.
  
  
  METHODS
  We examined the effect of kaffir lime leaves extract on growth and biofilm formation of S. mutans. For the investigation we used a kaffir lime extract with high phenolic content. The minimum inhibitory concentration of the extract was determined by broth microdilution assay. The inhibitory effect of the test substances on biofilm formation was also investigated by biofilm formation assay and qRT-PCR of biofilm formation-associated genes.
  
  
  RESULTS
  Kaffir lime leaves extract inhibits the growth of S. mutans, corresponding to the activity of an antibiotic, ampicillin. Formation of biofilm by S. mutans was also inhibited by the extract. These results were confirmed by the down-regulation of genes associated with the biofilm formation.
  
  
  CONCLUSIONS
  The findings highlight the ability of kaffir lime leaves extract to inhibit S. mutans activity, which may be beneficial in the prevention of biofilm formation on dental surface, reducing dental plaque and decreasing the chance of dental carries.
authors.affiliation: Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand.
authors.forename: Nateelak
authors.initials: N
authors.lastname: Kooltheat
authors.affiliation: Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand.
authors.forename: Ludthawun
authors.initials: L
authors.lastname: Kamuthachad
authors.affiliation: Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand.
authors.forename: Methinee
authors.initials: M
authors.lastname: Anthapanya
authors.affiliation: Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand.
authors.forename: Natthapon
authors.initials: N
authors.lastname: Samakchan
authors.affiliation: Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand; Thai Traditional Medicine College, Rajamangala University of Technology Thanyaburi, Pathum Thani, Thailand.
authors.forename: Rungnapa Pankla
authors.initials: RP
authors.lastname: Sranujit
authors.affiliation: Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand.
authors.forename: Pachuen
authors.initials: P
authors.lastname: Potup
authors.affiliation: Department of Immunopathology, SA Pathology at Women's and Children's Hospital, Robinson Research Institute, University of Adelaide, South Australia.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ferrante
authors.affiliation: Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand. Electronic address: ajkarn_9@hotmail.com.
authors.forename: Kanchana
authors.initials: K
authors.lastname: Usuwanthim
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects*; D002957:Citrus / Q000737:chemistry*; D003731:Dental Caries / Q000188:drug therapy; D015536:Down-Regulation; D008826:Microbial Sensitivity Tests; D010636:Phenols / Q000032:analysis / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D012329:RNA, Bacterial / Q000235:genetics; D013295:Streptococcus mutans / Q000187:drug effects*; D051996:Transcription Factor RelA / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C454866:BrpA protein, Streptococcus mutans; D010636:Phenols; D010936:Plant Extracts; D012329:RNA, Bacterial; D051996:Transcription Factor RelA; C119939:YycF protein, Bacteria
keywords: Biofilm formation; Kaffir lime; Minimum inhibitory concentration; Streptococcus mutans