# Study on the Enrichment Effect of Suillus luteus Polysaccharide on Intestinal Probiotics and the Immunomodulatory Activity

## TL;DR

This study explores how a polysaccharide from Suillus luteus boosts gut probiotics and immune response in tumor-bearing mice.

## Contribution

The novel contribution is the systematic characterization of S. luteus polysaccharide and its immunomodulatory effects in a tumor model.

## Key findings

- SLP has a molecular weight of ~1.90 × 10⁶ Da and a specific sugar composition.
- SLP enriched intestinal probiotics like Lactobacillus and Odoribacter in tumor-bearing mice.
- SLP administration enhanced CD4+ T cell immunity and suppressed tumor growth by 53.14%.

## Abstract

Suillus luteus is a highly prized edible fungus and demonstrates significant potential in the field of bioremediation, particularly for soil restoration and pollution mitigation. However, systematic research on the structural characteristics of the bioactive polysaccharides and regulatory effects on gut microbiota metabolism remains scarce. In this study, S. luteus polysaccharide (SLP) was obtained by hot water extraction and the structural characteristics were systematically determined, as well as the regulatory function on gut microbiota metabolism in a tumor-bearing mice model. Results showed that SLP exhibited an average molecular weight of approximately 1.90 × 106 Da with Fuc:Man:Glc:Gal molar ratio of 0.37:1.00:0.72:0.54. The polysaccharide predominantly employed β-(1→4)-Manp as the backbone with α-(1→3)-Fucp, α-(1→6)-Glcp, and α-(1→6)-Galp as side chains. SLP administration of 200 mg/kg in tumor-bearing mice exerted enrichment effects of intestinal probiotics, including Lactobacillus and Odoribacter, which were associated with alterations in glyoxylate and dicarboxylic acid metabolism, ultimately enhancing CD4+ T cell immunity and resulting in a tumor suppression rate of 53.14%. This study provides a theoretical foundation and supporting data for the development of S. luteus polysaccharide in the functional food field.