# Separation, Purification, Structural Characterization and Hypoglycemic Effect Study of Homogeneous Mori fructus Polysaccharide

## TL;DR

This study isolates and characterizes a homogeneous polysaccharide from Mori fructus and shows it has strong hypoglycemic effects.

## Contribution

The study provides the first detailed structural and functional analysis of a homogeneous Mori fructus polysaccharide.

## Key findings

- MFP-III has a molecular weight of 6.83 kDa and is composed of rhamnose, arabinose, galactose, glucose, mannose, and galacturonic acid.
- MFP-III strongly inhibits α-glucosidase and α-amylase, showing better activity than acarbose at the same concentration.
- The structural backbone of MFP-III is →2,4)-α-L-Rhap-(1 → 4)-α-D-GalpA-(1→ with potential branching units.

## Abstract

Background/Objectives: Mori fructus polysaccharides are key bioactive components with diverse activities, but structural characterization of homogeneous fractions remains limited, hindering insights into structure–activity relationships. This study addresses this gap by isolating and characterizing a homogeneous polysaccharide (MFP-III) from M. fructus. Methods: MFP-III, representing the final gel-filtration homogeneous fraction, was purified using defined procedures: DEAE-52 cellulose chromatography followed by Sephadex G-100 gel filtration. Purity and homogeneity were validated by high-performance liquid chromatography (HPLC). Structural characteristics were analyzed via HPLC, GC-MS, FTIR, and NMR spectroscopy. Meanwhile, hypoglycemic activity of MFP-III was evaluated. Results: MFP-III (94.2 ± 2.6%) has a molecular weight of approximately 6.83 kDa, primarily composed of rhamnose, arabinose, galactose, glucose, mannose, and galacturonic acid. Its backbone structure is presumed to be →2,4)-α-L-Rhap-(1 → 4)-α-D-GalpA-(1→, with branching units potentially attached to O-4. MFP-III demonstrated significant inhibitory activity against α-glucosidase (IC50 = 1.56 mg/mL) and α-amylase (IC50 = 2.07 mg/mL), stronger than acarbose at equivalent concentrations. Conclusions: The findings provide preliminary insights into the hypoglycemic structure–activity relationship of MFP-III, providing data support for the development of blood glucose-lowering natural inhibitors, and offering a theoretical foundation for advancing the application of polysaccharides from other sources.