# Isolation, Chemical Structure, and Antagonistic Activity Against Galectin‐1 of Water‐Soluble Polysaccharides From Plantago asiatica

## TL;DR

This study isolates and analyzes water-soluble polysaccharides from Plantago asiatica, finding that they can inhibit galectin-1 activity, which is linked to cancer progression.

## Contribution

The study identifies specific acidic polysaccharides from Plantago asiatica with strong galectin-1 antagonistic activity and anti-cancer potential.

## Key findings

- WPA-3 showed the strongest inhibition of galectin-1-mediated hemagglutination and fluorescence intensity.
- WPA-3 inhibited cervical cancer cell growth and migration more effectively than other fractions.
- WPA-3 exhibited a strong binding affinity to galectin-1 with a KD value of 26.8 nM.

## Abstract

Plantago asiatica
has been utilized as a dietary supplement in health foods and for medicinal purposes, enjoying a long‐standing acceptance throughout history. A neutral polysaccharide fraction (WPA‐N) and three acidic polysaccharide fractions (WPA‐1, WPA‐2, and WPA‐3) prepared from
Plantago asiatica
by water extraction and DEAE‐cellulose were tested for their chemical structures and inhibitory effects on galectin‐1‐mediated bioactivity. The results showed that WPA‐N was composed of Glc and Gal residues, while WPA‐1, WPA‐2, and WPA‐3 were mainly constituted by GalA, Gal, Ara, Rha, as well as some other monosaccharide residues, with the molecular weights ranging from 68.7 kDa to 168.2 kDa. Galectin‐1 has been identified as a mediator in the multi‐step process of tumor cell aggregation, migration, and invasion, as well as in tumor‐induced angiogenesis, including in cervical cancer. Except for WPA‐N, three acidic fractions could inhibit galectin‐1‐mediated hemagglutination and also could inhibit the fluorescence intensity of galectin‐1 protein, and WPA‐3 showed the strongest activity. Besides, anti‐cancer experiments showed three acidic fractions could inhibit the growth and migration of cervical cancer ME180 cells, and WPA‐3 inhibited the proliferation and migration activity of ME180 better than others. Biolayer interferometry analysis found that WPA‐3 had a very strong binding ability to galectin‐1 protein, with a KD value of 26.8 nM. WPA‐3 contained rhamnogalacturonan‐I mainchain with branched galactan, arabinan, and arabinogalactans‐II side chains and some homogalacturonan domain. These findings indicated the potential applications in functional food fields of
Plantago asiatica
polysaccharides.

Plantago asiatica has been utilized as a dietary supplement in health foods and for medicinal purposes, enjoying a long‐standing acceptance throughout history. This study will provide new insights into the relationship between the antagonistic activity against galectin‐1 of P.asiatica polysaccharides and their applications in the fields of food and medicine.