title: Cytotoxicity effect of degraded and undegraded kappa and iota carrageenan in human intestine and liver cell lines.
abstract: BACKGROUND
  Carrageenan is a linear sulphated polysaccharide extracted from red seaweed of the Rhodophyceae family. It has broad spectrum of applications in biomedical and biopharmaceutical field. In this study, we determined the cytotoxicity of degraded and undegraded carrageenan in human intestine (Caco-2; cancer and FHs 74 Int; normal) and liver (HepG2; cancer and Fa2N-4; normal) cell lines.
  
  
  METHODS
  Food grade k-carrageenan (FGKC), dried sheet k-carrageenan (DKC), commercial grade k-carrageenan (CGKC), food grade i-carrageenan (FGIC) and commercial grade i-carrageenan (CGIC) were dissolved in hydrochloric acid and water to prepare degraded and undegraded carrageenan, respectively. Carrageenan at the concentration range of 62.5 - 2000.0 μg mL(-1) was used in the study. MTT assay was used to determine the cell viability while the mode of cell death was determined by May-Grunwald Giemsa (MGG) staining, acridine orange-ethidium bromide (AO/EtBr) staining, agarose gel electrophoresis and gene expression analysis.
  
  
  RESULTS
  Degraded FGKC, DKC and CGKC showed IC50 in 24, 48 and 72 hours treated Caco-2, FHs 74 Int, HepG2 and Fa2N-4 cell lines as tested by MTT assay. Degraded FGIC and CGIC only showed its toxicity in Fa2N-4 cells. The characteristics of apoptosis were demonstrated in degraded k-carrageenan treated Caco-2, FHs 74 Int, HepG2 and Fa2N-4 cells after MGG staining. When Caco-2 and HepG2 cells were undergone AO/EtBr staining, chromatin condensation and nuclear fragmentation were clearly seen under the microscope. However, DNA ladder was only found in HepG2 cells after gel electrophoresis analysis. Degraded k-carrageenan also inactivated PCNA, Ki-67 and survivin gene in HepG2. On the other hand, undegraded FGKC, DKC, CGKC, FGIC and CGIC treated cells showed no cytotoxic effect after analyzed by the same analyses as in degraded carrageenan.
  
  
  CONCLUSIONS
  Degraded k-carrageenan inhibited cell proliferation in Caco-2, FHs 74 Int, HepG2 and Fa2N-4 cell lines and the anti-proliferative effect was related to apoptosis together with inactivation of cell proliferating genes as determined by morphological observation and molecular analysis. However, no cytotoxic effect was found in undegraded carrageenan towards normal and cancer intestine and liver cell lines.
authors.forename: Shahrul Hisham Zainal
authors.initials: SH
authors.lastname: Ariffin
authors.forename: Wong Woan
authors.initials: WW
authors.lastname: Yeen
authors.forename: Intan Zarina Zainol
authors.initials: IZ
authors.lastname: Abidin
authors.forename: Rohaya Megat
authors.initials: RM
authors.lastname: Abdul Wahab
authors.forename: Zaidah Zainal
authors.initials: ZZ
authors.lastname: Ariffin
authors.affiliation: Faculty of Science and Technology, School of Biosciences and Biotechnology, Universiti Kebangsaan Malaysia, 43600 Selangor, DE, Malaysia. sahidan@ukm.edu.my.
authors.forename: Sahidan
authors.initials: S
authors.lastname: Senafi
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D018938:Caco-2 Cells; D002351:Carrageenan / Q000009:adverse effects* / Q000737:chemistry; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D005503:Food Additives / Q000009:adverse effects / Q000737:chemistry; D056945:Hep G2 Cells; D006801:Humans; D007422:Intestines / Q000187:drug effects*; D008099:Liver / Q000187:drug effects*; D012624:Seaweed / Q000737:chemistry
chemical_list: D005503:Food Additives; D002351:Carrageenan