BackgroundCarrageenan 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.MethodsFood 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.ResultsDegraded 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.ConclusionDegraded 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.

Three specific orthodontic tooth movement genes, that is, FCRL1, HSPG2, and LAMB2 were detected at upper first premolar (with appliance) dental pulp tissue by using GeneFishing technique as compared to lower first premolar (without appliance). These three differentially expressed genes have the potential as molecular markers during orthodontic tooth movement by looking at molecular changes of pulp tissue.

Carrageenan is a sulphated polysaccharide derived from red seaweed from the class Rhodophyceae. Kappaphycus alvarezii and Eucheuma spinosum which yield kappa(k-) and iota(i-) carrageenan, respectively function as natural thickener or emulsifier in food products. Carrageenan is labelled as Generally Recognized As Safe by FDA. However, it is also used by scientist to induce gastrointestinal inflammation in animal where degraded carrageenan was proven to cause ulcerative colitis in animal model. In this study, anticytotoxicity and antioral bacterial activity of k-carrageenan, i-carrageenan and kappa seaweed crude powder were determined. Human hepatocellular carcinoma (HepG2) and human epithelial colorectal adenocarcinoma cells (Caco-2), as well as oral bacteria (3 gram positive and 3 gram negative) were treated with different concentration of carrageenan range from 0.005%-3% (w/v). k-carrageenan, i-carrageenan and kappa seaweed powder were supplied by Tacara Sdn Bhd, Sabah. Disc diffusion and broth dilution method were performed to test the antibacteria activity of carrageenan. The three carrageenan did not show IC 50 value on HepG2 and Caco-2 cells with the concentration tested range from 31.25-2000 µg/mL when screening by MTT assay. Meanwhile, carrageenan cannot inhibit the growing of oral bacteria. So we concluded that i-carrageenan, k-carrageenan and kappa seaweed crude powder were not toxic to HepG2 and Caco-2 cells, and they could not function as antioral bacteria agent. Biochemical and molecular analysis of effect of carrageenan on HepG2 and Caco-2 cells will be further investigated.