# Polysaccharides from Pleurotus eryngii: sequential extraction and structural characterization

## TL;DR

This paper introduces a new method to extract and analyze the complex sugars from the mushroom Pleurotus eryngii, revealing their diverse structures and abundance.

## Contribution

A novel sequential extraction method and the first identification of α-1,2-D-mannan in Pleurotus eryngii.

## Key findings

- Five distinct polysaccharide types were identified in Pleurotus eryngii with specific abundance ratios.
- The sequential extraction method significantly improved the total yield of polysaccharides compared to single methods.
- A new polysaccharide, α-1,2-D-mannan, was discovered in Pleurotus eryngii for the first time.

## Abstract

Polysaccharides, a primary component from Pleurotus eryngii (P. eryngii), have diverse biological activities. To systematically investigate structural features of these polysaccharides, we have developed a sequential extraction strategy with gradient-enhanced solvent-oriented purification that includes cold and hot water, enzymes assisted, dilute and concentrated alkali. Five polysaccharides CWP (0.19%), HWP (0.1%), EAP (0.14%), DAP (0.65%), CAP (0.34%) were obtained. The sequential extraction strategy developed here is practical, significantly improving the total extraction yield compared to single methods. After purification, we obtained eight homogeneous polysaccharides. Using several characterization techniques, we discovered that P. eryngii polysaccharides contained five structural types, including β-1,3-D-glucan, β-1,6-D-glucan, α-1,6-D-galactan, α-1,3-D-mannan, and a novel polysaccharide α-1,2-D-mannan, with ratios of 20:7:4.3:1.6:1. This study provides valuable insights into the structural diversity and relative abundance of polysaccharides in P. eryngii. Our findings provide a foundation for further investigation into their structure-activity relationships and potential applications.

•A sequential extraction method was developed for efficient extraction Pleurotus eryngii polysaccharides.•Pleurotus eryngii polysaccharides contained β-1,3/1,6-D-glucan, α-1,6-D-galactan and α-1,3/1,2-D-mannan.•The mass ratios of five types of polysaccharides in Pleurotus eryngii was 20:7:4.3:1.6:1.•α-1,2-D-mannan was first identified in Pleurotus eryngii.

A sequential extraction method was developed for efficient extraction Pleurotus eryngii polysaccharides.

Pleurotus eryngii polysaccharides contained β-1,3/1,6-D-glucan, α-1,6-D-galactan and α-1,3/1,2-D-mannan.

The mass ratios of five types of polysaccharides in Pleurotus eryngii was 20:7:4.3:1.6:1.

α-1,2-D-mannan was first identified in Pleurotus eryngii.