• Journal of Ginseng Research
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• v.44 no.4
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• pp.570-579
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• 2020

Background: Many researchers reported that the various immune activities of red ginseng are due to acid polysaccharides. But, the exact structural characteristics of the acidic polysaccharide in red ginseng have not been fully elucidated. Therefore, we isolated the acidic polysaccharide from red ginseng and characterized the structural property of the active moiety of this polysaccharide, which contributes to the immunostimulatory activity of red ginseng. Methods: A polysaccharide (RGP-AP-I) was purified from red ginseng via size-exclusion chromatography using Sephadex G-100. Immunostimulatary activity of RGP-AP-I was investigated via anti-complementory and macrophage stimulatory activity. The structure of RGP-AP-I was characterized by HPLC, sugar composition, β-glucosyl Yariv reagent and methylation analysis. Results: Peritoneal macrophages stimulated using RGP-AP-I significantly augmented the production of various cytokines such as interleukin (IL)-6, IL-12, and tumor necrosis factor (TNF)-α. The primary structure of RGP-AP-I was elucidated by assessing its sugar composition and methylation analysis. RGP-AP-I is a 96 kDa acidic polysaccharide, and comprises nine different monosaccharides, which mainly include sugars such as rhamnose (Rha, 9.5%), galacturonic acid (GalA, 18.4%), galactose (Gal, 30.4%), and arabinose (Ara, 35.0%). RGP-AP-I exhibited an considerable reaction with the β-glucosyl Yariv reagent, revealing the presence of arabino-β-3,6-galactan. Methylation analysis indicated that RGP-AP-I comprises 21 different glycosyl linkages, such as 3-, 4-, 6- and 3,6-linked Galp; 5-linked Araf; 2,4-linked Rhap; and 4-linked GalAp, which are characteristics of rhamnogalacturonan I (RG-I). Conclusion: we assumed that the immunostimulatory activity of RGP-AP-I may be due to the RG-I structure, which comprises a main chain with a repeating linkage unit, [→2)-Rhap-(1→4)-GalAp-(1→] and three groups of side chains such as (1→5)-linked arabinan, (1→4)-linked galactan, and arabino-β-3,6-galactan, which branch at the C(O)4 positions of Rha residues in the main chain of RGP-AP-I.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.595-603
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• 2020

To elucidate the structure-function relationship of polysaccharides obtained from Colocasia esculenta, the immuno-stimulating polysaccharide, CE-4a was purified to homogeneity from the crude polysaccharide (CE) extracted from the corms of C. esculenta by two subsequent column chromatographies using DEAE-Sepharose FF and Sephadex G-100, and analysis of their immuno-stimulatory activities and structure were conducted. CE-4a showed an increase in anti-complementary activity in a dose-dependent fashion. The molecular mass was estimated to be 182.4 kDa, which mainly consisted of galactose (43.5%) and mannose (18.2%). Methylation analysis indicated that CE-4a comprised at least 10 different glycosyl linkages, such as terminal Galp, 3-linked Galp, and 4-linked Manp, as well as a characteristic linkage, 2,4,6-branched Manp residue. To analyze the fine structure of CE-4a, it was sequentially digested using endo-α-(1→4)-polygalacturonase, exo-α-galactosidase and endo-β-1,4-D-mannanase. These analyses suggested that CE-4a is to be a highly branched galactomannan with a (1→4)-mannan backbone and galactopyranosyl oligosaccharide side chains.