Characterization of Different Salt Forms of Chitooligosaccharides and Their Effects on Nitric Oxide Secretion by Macrophages.

Ronge Xing,Pengcheng Li,Kun Gao,Yongliang Liu,Haoyue Yang,Huahua Yu,Song Liu,Chaojie Xu,Yukun Qin,Zhaoqian Fan

doi:10.3390/molecules26092563

Abstract

In this paper, chitooligosaccharides in different salt forms, such as chitooligosaccharide lactate, citrate, adipate, etc., were prepared by the microwave method. They were characterized by SEM, FTIR, NMR, etc., and the nitric oxide (NO) expression was determined in RAW 264.7 cells. The results showed that pure chitooligosaccharide was an irregular spherical shape with rough surface, and its different salt type products are amorphous solid with different honeycomb sizes. In addition to the characteristic absorption peaks of chitooligosaccharides, in FTIR, the characteristic absorption of carboxyl group, methylene group, and aromatic group in corresponding acid appeared. The characteristic absorption peaks of carbon in carboxyl group, hydrogen and carbon in methyl, methylene group, and aromatic group in corresponding acid also appeared in NMR. Therefore, the sugar ring structure and linking mode of chitooligosaccharides did not change after salt formation of chitooligosaccharides. Different salt chitooligosaccharides are completely different in promoting NO secretion by macrophages, and pure chitooligosaccharides are the best.

Highlights

Chitosan is the deacetylation product of chitin from the shell of crustacean, plant, and fungal cell walls
In addition to molecular weight and degree of acetylation, salt type is a major factor affecting the activity of chitosan
Chitooligosaccharide was of irregular spherical shape with rough surface, in addition to chitooligosaccharide citrate (COS-Cit), chitooligosaccharide malate (COS-Mal), and chitooligosaccharide succinate (COS-Suc), other different salt products are massive, with different honeycomb sizes

Summary

Introduction

Chitosan is the deacetylation product of chitin from the shell of crustacean, plant, and fungal cell walls. It is the only natural polysaccharide with cation found in nature so far. Because chitosan is insoluble in water, alkaline solution, and organic solvent, and is only soluble in some organic acids and dilute inorganic acid, such as acetic acid, dilute hydrochloric acid, etc., its application is greatly limited. Some studies have shown that chitosan salt formed with organic and inorganic acids is soluble in water and has been widely studied as a polymer drug carrier and a novel drug absorption accelerator across nasal and intestinal epithelium [11,12]. Different chitosan salt forms showed different drug release profiles. In addition to molecular weight and degree of acetylation, salt type is a major factor affecting the activity of chitosan

Methods

Results

Conclusion