title: Isolation and Characterisation of a Proanthocyanidin With Antioxidative, Antibacterial and Anti-Cancer Properties from FernBlechnum orientale.
abstract: BACKGROUND
  Blechnum orientaleLinn. (Blechnaceae), a fern, is traditionally used in the treatment of various ailments, such as skin diseases, stomach pain, urinary bladder complaints, and also as a female contraceptive. Previously, we reported a strong radical scavenging activity, antibacterial activity and cytotoxicity against HT29 colon cancer cells by aqueous extract ofB. orientale.
  
  
  OBJECTIVE
  In this study, we attempted to isolate and identify the active compound from the aqueous extract ofB. orientale.
  
  
  METHODS
  Aqueous extract ofB. orientalewas subjected to repeated MCI gel chromatography, Sephadex-LH-20, Chromatorex C18 and semi-preparative high performance liquid chromatography and was characterized using nuclear magnetic resonance and electrospray ionization mass-spectrometry spectroscopic methods. Antioxidant activity was determined using 2, 2-diphenyl-1-picrylhydrazyl radical scavenging assay. Antibacterial assays were conducted using disc diffusion whereas the minimum inhibitory concentration (MIC) and minimum bactericidal concentration were determined using the broth microdilution assay. Cytotoxicity was assessed using thiazolylblue tetrazoliumbromide.
  
  
  RESULTS
  A polymeric proanthocyanidin consisting of 2-12 epicatechin extension units and epigallocathecin terminal units linked at C4-C8 was elucidated. Bioactivity studies showed strong radical scavenging activity (IC50= 5.6 ± 0.1 µg/mL), antibacterial activity (MIC = 31.3-62.5 µg/mL) against five gram-positive bacteria and selective cytotoxicity against HT29 colon cancer cells (IC50= 7.0 ± 0.3 µg/mL).
  
  
  CONCLUSIONS
  According to our results, the proanthocyanidin ofB. orientaledemonstrated its potential as a natural source of antioxidant with antibacterial and anti-cancer properties.
  
  
  CONCLUSIONS
  A bioactive proanthocyanidin was isolated from the aqueous extract of medicinal fernBlechnum orientaleLinn and the structure was elucidated using NMR and ESI-MS spectral studies.The proanthocyanidin compound possessed strong radical scavenging activity (IC505.6 ± 0.1 µg/mL)The proanthocyaniding compound showed bactericidal activity against five gram-positive bacteria inclusive of MRSA (minimum inhibitory concentration, MIC and minimum bactericidal concentration, MBC 31.3-62.5 µg/mL).The proanthocyanidin compound is strongly cytotoxic towards cancer cells HT29 (IC507.0 ± 0.3 µg/mL), HepG2 (IC5016 µg/mL) and HCT116 (IC5020 µg/mL) while weakly cytotoxic towards the non-malignant Chang cells (IC5048 µg/mL).Abbreviation used:CC: Column chromatography, DP: degree of polymerization, DPPH: 2,2-diphenyl-1-picrylhydrazyl, ESI-MS: electronsprayionisation mass-spectrometry, MBC: Minimum bactericidal concentration, MIC: Minimum inhibitory concentration, MTT: Thiazolyl Blue Tetrazolium Bromide, MRSA: methicillin-resistantStaphylococcus aureus, NMR: nuclear magnetic resonance, TLC: thin layer chromatography, PD: prodelphinidin.
authors.affiliation: School of Biosciences, Taylor's University, Jalan Taylor's, Subang Jaya, Selangor, Malaysia.
authors.forename: How-Yee
authors.initials: HY
authors.lastname: Lai
authors.affiliation: School of Science, Monash University Sunway Campus, Bandar Sunway, Petaling Jaya, Selangor, Malaysia.
authors.forename: Yau-Yan
authors.initials: YY
authors.lastname: Lim
authors.affiliation: Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Kah-Hwi
authors.initials: KH
authors.lastname: Kim
keywords: Antibacterial; antioxidant; blechnum orientale; colon cancer; cytotoxicity proanthocyanidin