title: Analysis of the neutral polysaccharide fraction of MCP and its inhibitory activity on galectin-3.
abstract: The pH-modified citrus pectin (MCP) has been demonstrated to inhibit galectin-3 in cancer progression. The components and structures of MCP related to this inhibition remained unknown. In this paper, we fractionated MCP on DEAE-cellulose column into a homogenous neutral fraction MCP-N (about 20 kDa) and a pectin mixture fraction MCP-A (wide molecular distribution on Sepharose CL-6B chromatography). Both MCP-N and MCP-A inhibited hemagglutination mediated by galectin-3 with minimum inhibition concentration (MIC) 625 and 0.5 μg/ml, respectively. MCP-N was identified to be a type I arabinogalactan (AG-I) with a main chain of β-1→4-galactan. MCP-N was digested by α-L-arabinofuranosidase to give its main chain structure fraction (M-galactan, around 18 kDa), which was more active than the original molecule, MIC 50 μg/ml. The acidic degradation of M-galactan increased the inhibitory activity, MIC about 5 times lower than M-galactan. These results above showed that the functional motif of the β-1→4-galactan fragment might lie in the terminal residues rather than in the internal region of the chain. Therefore, MCP-N and its degraded products might be developed to new potential galectin-3 inhibitors. This is the first report concerning the fractionation of MCP and its components on galectin-3 inhibition. The information provided in this paper is valuable for screening more active galectin-3 inhibitors from natural polysaccharides.
authors.affiliation: School of Life Sciences, Northeast Normal University, 5268 Renmin Street, Changchun, 130024, People's Republic of China.
authors.forename: Xiaoge
authors.initials: X
authors.lastname: Gao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhi
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Huiting
authors.initials: H
authors.lastname: Xue
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Foday
authors.forename: Guihua
authors.initials: G
authors.lastname: Tai
authors.forename: Yifa
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000818:Animals; D002449:Cell Aggregation; D002478:Cells, Cultured; D002645:Chickens; D002957:Citrus / Q000378:metabolism; D005685:Galactans / Q000032:analysis* / Q000737:chemistry; D037502:Galectin 3 / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000378:metabolism; D010368:Pectins / Q000737:chemistry* / Q000378:metabolism; D011134:Polysaccharides / Q000032:analysis* / Q000737:chemistry
chemical_list: D005685:Galactans; D037502:Galectin 3; D011134:Polysaccharides; D010368:Pectins; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase; C005653:arabinogalactan