# Selenium-induced structural reorganization of polysaccharides from blackened jujube pomace enhances immunomodulatory activity

## TL;DR

This study shows that adding selenium to polysaccharides from jujube pomace improves their ability to modulate the immune system.

## Contribution

The novel approach of selenylation enhances polysaccharide bioactivity through structural reorganization.

## Key findings

- Selenylation reduced molecular weight and increased crystallinity of the polysaccharides.
- BJPP-Se showed stronger immunomodulatory effects in immunosuppressed mice compared to native polysaccharides.
- Two distinct Se (IV) coordination modes were identified using density functional theory calculations.

## Abstract

Natural polysaccharides exhibit promising pharmacological potential in functional foods. However, their structural heterogeneity and limited bioactivity hinder further applications.

In this study, a polysaccharide from blackened jujube pomace was selenylated via the conventional HNO3-Na2SeO3 route, with systematic optimization of reaction parameters to improve controllability, yielding selenium-enriched polysaccharides (BJPP-Se).

Multimodal characterization confirmed successful selenylation, with a reduction in molecular weight from 88.26 kDa to 74.32 kDa and an increase in crystallinity. Density functional theory calculations identified two distinct Se (IV) coordination modes, with one involving Se (IV) as a bridging atom linking two monosaccharide units and the other restricting Se (IV) coordination to a single monosaccharide unit. BJPP-Se has much stronger immunomodulatory performance than native polysaccharides in cyclophosphamide suppressed immunosuppressed mice. Selenium-induced structural reorganization is a very good example of how to design bioactive polysaccharides. This work supports the potential for valorizing polysaccharides from black jujube pomace; however, large-scale techno-economic feasibility and cost–benefit assessment are beyond the scope of this study and warrant future work with clearly defined boundaries and engineering-scale datasets.