Isolation and characterization of immunostimulatory polysaccharide from an herb tea, Gynostemma pentaphyllum Makino.

Key Laboratory of Ministry of Education for Medicinal Plant Resource and Natural Pharmaceutical Chemistry, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China.
Journal of Agricultural and Food Chemistry (Impact Factor: 2.91). 08/2008; 56(16):6905-9. DOI:10.1021/jf801101u
Source: PubMed

ABSTRACT Water-soluble polysaccharide from Gynostemma pentaphyllum herb tea (PSGP) was isolated by hot-water extraction and ethanol precipitation. The chemical components and preliminary immunomodulating activity of PSGP were investigated both in vitro and in vivo. Capillary zone electrophoresis analysis showed that PSGP was a typical nonstarch heteropolysaccharide, with glucose being the main component monosaccharide (23.2%), followed by galactose (18.9%), arabinose (10.5%), rhamnose (7.7%), galacturonic acid (4.7%), xylose (3.9%), mannose (3.1%), and glucuronic acid (1.2%). PSGP could significantly stimulate peritoneal macrophages to release nitric oxide, reactive oxygen species, and tumor necrosis factor-alpha in a dose-dependent manner. This immunostimulating activity of PSGP was further demonstrated by its inhibition on the proliferation of human colon carcinoma HT-29 and SW-116 cells incubated with the supernatant of PSGP-stimulated macrophage culture. It is evident that PSGP is a very important ingredient responsible for at least in part the immunomodulating activity of G. pentaphyllum herb tea.

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