title: Low molecular weight procyanidins from grape seeds enhance the impact of 5-Fluorouracil chemotherapy on Caco-2 human colon cancer cells.
abstract: OBJECTIVE
  Grape seed procyanidins (PC) are flavan-3-ol oligomers and polymers known for their biological activity in the gut. Grape seed extract (GSE) have been reported to reduce intestinal injury in a rat model of mucositis. We sought to investigate effects of purified PC fractions differing in mean degree of polymerization (mDP) combined with 5-Fluorouracil (5-FU) chemotherapy on the viability of colon cancer cells (Caco-2).
  
  
  METHODS
  SixPC fractions (F1-F6) were isolated from Cabernet Sauvignon seeds at two ripeness stages: pre-veraison unripe (immature) and ripe (mature), utilizing step gradient, low-pressure chromatography on a Sephadex LH-20 resin. Fractions were tested on Caco-2 cells, alone and in combination with 5-FU. Eluted fractions were characterized by phloroglucinolysis and gel permeation chromatography. Cell viability was determined by the 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide) (MTT) assay.
  
  
  RESULTS
  All isolated fractions significantly reduced Caco-2 cell viability compared to the control (P<0.05), but F2 and F3 (mDP 2-6) were the most active fractions (immature F2 = 32% mDP 2.4, F3 = 35% mDP 5.8 and mature F2 = 13% mDP 3.6 and F3 = 17% mDP 5.9; percentage of viable cells remaining) on Caco-2 cells. When combined with 5-FU, immature fractions F1-F3 enhanced the cell toxicity effects of 5-FU by 27-73% (P<0.05). Mature seed PC fractions (F1-F4) significantly enhanced the toxicity of 5-FU by 60-83% against Caco-2 cells (P<0.05). Moreover, some fractions alone were more potent at decreasing viability in Caco-2 cells (P<0.05; immature fractions = 65-68% and mature fractions = 83-87%) compared to 5-FU alone (37%).
  
  
  CONCLUSIONS
  PCs of mDP 2-6 (immature F1-F3 and mature F1 and F4)not only enhanced the impact of 5-FU in killing Caco-2 cells, but also surpassed standard 5-FU chemotherapy as an anti-cancer agent.The bioactivity of PC is therefore attributed primarily to lower molecular weight PCs.
authors.affiliation: Wine Science and Business Group, School of Agriculture, Food and Wine, Waite Campus, The University of Adelaide, PMB 1, Glen Osmond, Australia; Centre for Paediatric and Adolescent Gastroenterology, Children, Youth and Women's Health Service, North Adelaide, Australia.
authors.forename: Ker Y
authors.initials: KY
authors.lastname: Cheah
authors.affiliation: Centre for Paediatric and Adolescent Gastroenterology, Children, Youth and Women's Health Service, North Adelaide, Australia; School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Australia.
authors.forename: Gordon S
authors.initials: GS
authors.lastname: Howarth
authors.affiliation: The Australian Wine Research Institute, Urrbrae, Adelaide, Australia.
authors.forename: Keren A
authors.initials: KA
authors.lastname: Bindon
authors.affiliation: The Australian Wine Research Institute, Urrbrae, Adelaide, Australia; Department of Viticulture and Enology, California State University, Fresno, California, United States of America.
authors.forename: James A
authors.initials: JA
authors.lastname: Kennedy
authors.affiliation: Wine Science and Business Group, School of Agriculture, Food and Wine, Waite Campus, The University of Adelaide, PMB 1, Glen Osmond, Australia.
authors.forename: Susan E P
authors.initials: SE
authors.lastname: Bastian
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D044946:Biflavonoids / Q000737:chemistry* / Q000494:pharmacology*; D018938:Caco-2 Cells; D002392:Catechin / Q000737:chemistry* / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D003110:Colonic Neoplasms / Q000473:pathology*; D004357:Drug Synergism; D005472:Fluorouracil / Q000494:pharmacology*; D056604:Grape Seed Extract / Q000737:chemistry*; D006801:Humans; D008970:Molecular Weight; D044945:Proanthocyanidins / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D000975:Antioxidants; D044946:Biflavonoids; D056604:Grape Seed Extract; D044945:Proanthocyanidins; C017674:procyanidin; D002392:Catechin; D005472:Fluorouracil