# Steaming duration-dependent effects on the in vivo distribution, anti-fatigue activity, and gut microbiota modulation of Polygonatum cyrtonema Hua polysaccharides

## TL;DR

This study shows that steaming Polygonatum cyrtonema rhizomes changes the structure of its polysaccharides, affecting their anti-fatigue effects and gut microbiota interactions.

## Contribution

The study reveals how steaming duration alters polysaccharide function and anti-fatigue activity through gut microbiota modulation.

## Key findings

- All PCPs showed poor systemic absorption but prolonged colonic retention.
- 12-h steaming reduced fatigue markers like lactate and lactate dehydrogenase.
- 4-h and 8-h steaming increased short-chain fatty acids and gut microbial diversity.

## Abstract

Polygonatum cyrtonema Hua is a traditional medicinal plant widely used for its anti-fatigue properties, with its polysaccharides (PCPs) believed to play a key role in these effects. Steaming, a necessary step before consumption, can alter the structure of PCPs. However, the impact of steaming-induced structural changes on their anti-fatigue activity remains unexplored. This study aims to investigate how different steaming durations affect the distribution, anti-fatigue activity, and modulation of gut microbiota by PCPs.

P. cyrtonema rhizomes were steamed for 0, 4, 8, and 12 h, and the polysaccharides were extracted. In vivo distribution was evaluated by conjugating PCPs with fluorescein isothiocyanate (FITC) for optical imaging. Anti-fatigue effects were assessed via exhaustive swimming tests, and serum biochemical markers were analyzed. Short-chain fatty acids (SCFAs) in feces were quantified by gas chromatography, while gut microbiota composition was analyzed using 16S rRNA sequencing. Network pharmacology analysis was performed to identify the biological targets of PCPs and their role in fatigue.

The results showed that all four PCPs exhibited poor systemic absorption but prolonged colonic retention, suggesting that interactions with the gut microbiota are central to their biological effects. While all PCPs improved exercise endurance, the 12-h steaming treatment notably decreased biochemical markers such as lactate and lactate dehydrogenase levels. Microbiota analysis revealed increased gut microbial α-diversity and short-chain fatty acids (SCFAs), with the 4-h and 8-h steaming groups showing the highest SCFA levels. β-diversity analysis indicated distinct microbial shifts, particularly between raw and steamed samples. Network pharmacology analysis highlighted differences in the mechanisms between raw and steamed PCPs, identifying key biological targets related to the anti-fatigue effects. The analysis suggested that the duration of steaming affects the biological activity of PCPs by modulating key metabolic pathways and targets involved in fatigue.

These findings suggest that steaming-induced structural changes affect function and that the duration of steaming plays a crucial role in preserving the anti-fatigue effects of P. cyrtonema rhizomes. The results provide valuable insights for optimizing the steaming process to enhance the anti-fatigue potential of P. cyrtonema.

Flowchart depicting the process of steaming and preparing polysaccharides (PCPs) from P. Cyrtonema Hua rhizomes. It includes sections on steaming, in vivo fluorescence imaging, anti-fatigue effects, gut microbiota composition, and network pharmacology analysis. Visuals involve images of rhizomes, imaging equipment, graphs on swimming endurance, microbiota composition, and a Venn plot with a network diagram. Arrows indicate process flow, with emphasis on the central role of gut microbiota and differences between raw and steamed PCPs.