Characterization of a pectic polysaccharide from the leaves of Diospyros kaki and its modulating activity on lymphocyte proliferation.
Pectin is a group of carbohydrate polymers constructing the primary cell walls and the middle lamella of terrestrial plants. Herein, we demonstrated the structure and immunomodulatory activity of the major pectic polysaccharide DL-3B(2) isolated from the leaves of Diospyros kaki. Based on composition analysis, methylation analysis, two-step acid hydrolysis, lithium-mediated selective degradation, (13)C NMR spectroscopy, and electrospray ionization mass spectrometry, DL-3B(2) was found to contain an alpha-1, 4-linked galacturonic acid (GalA) backbone with some insertions of alpha-1, 2-linked rhamnose residues. The arabinan- and arabinogalactan-side chains were attached to O-4 of the rhamnose residues, whereas the linear arabinoxylan was probably linked to O-3 of the GalA residues. Immunological tests in vitro showed that DL-3B(2) could help stimulate lipopolysaccharide-induced B lymphocyte proliferation, but not ConA-induced T lymphocyte proliferation, and that the arabinose residues play a role in maintaining this immunological activity.
Duan
Jinyou
J
Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, People's Republic of China. jduan@rics.bwh.harvard.edu
Dong
Qun
Q
Ding
Kan
K
Fang
Jinian
J
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D029788:Diospyros / Q000737:chemistry*; D005503:Food Additives / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D051379:Mice; D010368:Pectins / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
D005503:Food Additives; D010368:Pectins