Extraction, Characterization and Immunological Activity of Polysaccharides from Rhizoma gastrodiae.

Juncheng Chen,Shan Tian,Hongtao Du,Xiaoying Shu,Na Li,Junru Wang

doi:10.3390/ijms17071011

Abstract

A response surface and Box-Behnken design approach was applied to augment polysaccharide extraction from the residue of Rhizoma gastrodiae. Statistical analysis revealed that the linear and quadratic terms for three variables during extraction exhibited obvious effects on extraction yield. The optimum conditions were determined to be a liquid-to-solid ratio of 54 mL/g, an extraction temperature of 74 °C, an extraction time of 66 min, and three extractions. These conditions resulted in a maximum Rhizoma gastrodiae polysaccharide (RGP) extraction yield of 6.11% ± 0.13%. Two homogeneous polysaccharides (RGP-1a and RGP-1b) were obtained using DEAE cellulose-52 and Sephadex G-100 columns. The preliminary characterization of RGP-1a and RGP-1b was performed using HPLC-RID, HPGPC, and FTIR. Tests of the immunological activity in vitro showed that the two polysaccharides could significantly stimulate macrophages to release NO and enhance phagocytosis in a dose-dependent manner. In particular, RGP-1b (200 μg/mL) and LPS (2 μg/mL) had almost the same influence on the NO production and phagocytic activity of RAW 264.7 macrophages (p > 0.05). All the data obtained indicate that RGP-1a and RGP-1b have the potential to be developed as a health food.

Highlights

Polysaccharides constitute long chains or molecular strands of monosaccharides connected by glycosidic linkages
The yield decreased when the extraction time was above 70min, because too long an extraction time can lead to degradation of polysaccharide [23]
The sugar contents of Rhizoma gastrodiae polysaccharide (RGP)-1a and RGP-1b were 92.53% and 96.88%, respectively, and no uronic acid or protein was found in the two polysaccharides

Summary

Introduction

Polysaccharides constitute long chains or molecular strands of monosaccharides connected by glycosidic linkages. These polymeric carbohydrate arrangements are found almost exclusively in animals, plants, and microbes. It has been used to treat convulsion, neurasthenia, headache, ischemia, vertigo, dementia, and hemiplegia [14,15,16,17] Phenolic compounds, such as gastrodin, 4-hydroxybenzyl alcohol and parishin B, are the main bioactive constituents of rhizoma gastrodiae [18,19,20], and recent research has indicated that Rhizoma gastrodiae polysaccharide (RGP) is an important active substance. Ming’s team [21] isolated the polysaccharide PGEB-3H from Rhizoma gastrodiae and found that it has hypolipidemic activity, while Chen’s group [22] reported that a RGP has anti-cancer activity. Some studies have been done on RGP, reports on the structure and activity of this polysaccharide are limited

Methods

Results

Conclusion