title: Anti-biofilm activity of Marula - a study with the standardized bark extract.
abstract: BACKGROUND
  Marula (Sclerocarya birrea; family - Anacardiaceae) is an African plant, which enjoys wide socio-economic importance particularly in southern part of Africa. The fruits are consumed as food and also as alcoholic beverage (cream liquor). In different parts of Africa, the decoction of the bark is traditionally used for the treatment of dysentery, diarrhoea, and various other infectious conditions. The aim of the study was to investigate the anti-biofilm properties of the methanol extract of Marula bark (stem bark of Sclerocarya birrea), with a view towards combating the emergence of antimicrobial resistance often associated with bacterial biofilms.
  
  
  METHODS
  The standardized methanol extract was initially tested for its antimicrobial property. The crystal violet assay was used for evaluating anti-biofilm (biofilm formation by Pseudomonas aeuginosa) activity. Further in order to study the mechanism of anti-biofilm activity, the same was evaluated for understanding its role on various quorums sensing mediated phenomenon (swarming motility assay, protease and pyoverdin assay) that are known to be associated with the formation of biofilms and pathogenicity.
  
  
  RESULTS
  The methanol extract showed no inhibition of bacterial growth up to a concentration of 200 µg/ml. Interestingly, the sample produced anti-biofilm activity (around 75% decrease; 100 µg/ml) at sub-lethal concentration. Further it also significantly reduced the QS mediated swarming motility. The release of various virulent factors (protease and pyoverdin) was found to be lowered when pre-treated with the extract.
  
  
  CONCLUSIONS
  The present study illustrates the anti-biofilm property Sclerocarya birrea. The standardized extract significantly disrupted the quorum sensing mediated production of biofilm formation and also inhibited swarming ability of the cells. The extract displayed a regulatory role on the secretion of protease and pyoverdin, two QS dependent pathogenic factors found in Pseudomonas aeruginosa. This study also validates the ethnobotanical use of Marula.
authors.affiliation: School of Natural Product Studies, Jadavpur University, Kolkata 700032, India; Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Ratul
authors.initials: R
authors.lastname: Sarkar
authors.affiliation: School of Natural Product Studies, Jadavpur University, Kolkata 700032, India.
authors.forename: Sushil K
authors.initials: SK
authors.lastname: Chaudhary
authors.affiliation: Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Amrita
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Kirendra K
authors.initials: KK
authors.lastname: Yadav
authors.affiliation: School of Natural Product Studies, Jadavpur University, Kolkata 700032, India.
authors.forename: Neelesh K
authors.initials: NK
authors.lastname: Nema
authors.affiliation: IKS (Health) Research Unit, Medical Research Council, Parow Valley, Cape Town, South Africa.
authors.forename: Mamello
authors.initials: M
authors.lastname: Sekhoacha
authors.affiliation: School of Natural Product Studies, Jadavpur University, Kolkata 700032, India; Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Sanmoy
authors.initials: S
authors.lastname: Karmakar
authors.affiliation: Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Fernão C
authors.initials: FC
authors.lastname: Braga
authors.affiliation: IKS (Health) Research Unit, Medical Research Council, Parow Valley, Cape Town, South Africa.
authors.forename: Motlalepula Gilbert
authors.initials: MG
authors.lastname: Matsabisa
authors.affiliation: School of Natural Product Studies, Jadavpur University, Kolkata 700032, India; Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Pulok K
authors.initials: PK
authors.lastname: Mukherjee
authors.affiliation: School of Natural Product Studies, Jadavpur University, Kolkata 700032, India; Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India. Electronic address: tssen@hotmail.com.
authors.forename: Tuhinadri
authors.initials: T
authors.lastname: Sen
mesh_terms: D027926:Anacardiaceae; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects*; D002364:Caseins / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D024301:Plant Bark; D010936:Plant Extracts / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D053038:Quorum Sensing / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002364:Caseins; D009842:Oligopeptides; D010936:Plant Extracts; C026018:azocasein; C042453:pyoverdin; D010447:Peptide Hydrolases
keywords: Biofilm; Marula; Pyoverdin; Quorum sensing; Virulence