Polysaccharides with immunomodulating activity from roots of Gentiana crassicaulis

Two polysaccharides, GCP-I-I and GCP-II-I, were obtained from 100°C water extracts of Gentiana crassicaulis roots by DEAE anion exchange chromatography and gel filtration. The results from methanolysis, methylation, FT-IR and NMR, indicated that these two fractions are typical pectic polysaccharides, with HG and RG-I regions and AG-I/AG-II side chains, and some of the galacturonic acid units of fraction GCP-I-I were methyl esterified. Fractions GCP-I-I and GCP-II-I, both exhibited potent complement fixation, and fraction GCP-I-I was more potent than positive control BPII. The higher complement fixation activity obtained in fraction GCP-I-I may be due to the higher Mw and/or higher amount of AG-II present in fraction GCP-I-I than fraction GCP-II-I. The polysaccharides from G. crassicaulis could be used as a potential natural immunomodulator.