Main content area

Analysis of pectin from Panax ginseng flower buds and their binding activities to galectin-3

Cui, Liangnan, Wang, Jiayi, Huang, Rui, Tan, Ya, Zhang, Fan, Zhou, Yifa, Sun, Lin
International journal of biological macromolecules 2019 v.128 pp. 459-467
Panax ginseng, arabinogalactans, chemical bonding, enzymatic hydrolysis, flower buds, galectins, interferometry, ion exchange, nuclear magnetic resonance spectroscopy, polygalacturonic acid, stable isotopes, structure-activity relationships, water solubility
Water-soluble pectic polysaccharides isolated from Panax ginseng flower buds (WGFPA) were completely fractionated into six homogeneous fractions (WGFPA-1a, WGFPA-2a, WGFPA-3a, WGFPA-1b, WGFPA-2b and WGFPA-3b) by a combination of ion-exchange and size exclusion chromatographies. Monosaccharide composition, enzymatic hydrolysis and 13C nuclear magnetic resonance (NMR) spectra analysis were combined to characterize their structural features. Furthermore, the interactions between these polysaccharides and galectin-3 were evaluated by biolayer interferometry assay. The results showed that WGFPA-1a, WGFPA-2a and WGFPA-3a were rhamnogalacturonan I (RG-I) type pectin with abundant side chains, including α-L-1,5-arabinan, β-D-1,4-galactan, arabinogalactan I (AG-I) and arabinogalactan II (AG-II), exhibiting strong binding activities to galectin-3 with apparent KD values 4.9 μM, 0.71 μM and 0.24 μM, respectively. WGFPA-1b, WGFPA-2b and WGFPA-3b were homogalacturonan (HG) type pectin covalently linked with different ratios of rhamnogalacturonan II (RG-II) domains, showing weaker or no interactions with galectin-3. This study provides useful structural information for further investigation on the structure-activity relationship of ginseng flower buds pectin.