Polysaccharides Analysis Service

Polysaccharides are linked by the glycosidic bond of more than 10 monosaccharide molecules. They have relatively large molecular weights and are usually composed of hundreds to thousands of monosaccharide units. Nucleic acids, proteins, lipids, and polysaccharides are considered the four essential substances of life, playing crucial roles in numerous biological activities, including immune regulation, anti-tumor effects, reduction of blood glucose and blood lipids, antiviral activity, elimination of oxidative free radicals, and anti-aging effects. Polysaccharides are widely distributed in higher plants, animals, algae, and bacteria in nature. Most polysaccharides derived from tissue cells have low toxicity, and cause fewer side effects on cells and the body, making them ideal drug sources. In recent years, with the rapid development of related disciplines such as biology and chemistry, research on polysaccharide has received growing attention. The international scientific community regards polysaccharide research as a frontier field in life sciences, with some even proposing that the 21st century is the century of polysaccharides.

 

Analysis Workflow

1. Polysaccharide Extraction

Polysaccharides are connected to cell walls or interstitial substances through hydrogen or ionic bonds. Different extraction methods are used depending on the existence of the polysaccharides. Common solvents include hot water, acid, alkali, and ethanol, with extraction processes often assisted by microwaves or ultrasound. Common methods include supercritical fluid extraction and complex enzyme-assisted extraction techniques. These methods enable specific degradation of cell walls and the barrier for intracellular macromolecular dissolution under mild conditions to accelerate polysaccharide release. Additionally, the reaction can be controlled by adjusting system conditions based on enzyme characteristics.

 

2. Removal of Polysaccharide Impurities

Crude polysaccharide extracts usually contain impurities such as inorganic salts, lipids, proteins, and low-molecular non-polar substances. Low molecular weight impurities can be removed using dialysis. Proteins can be removed using protease methods, Sevag methods, TCA methods, and trichlorotrifluoroethane methods. Fats can be removed using organic solvents such as ethanol, ether, and petroleum ether. Common methods for removing pigment impurities include adsorption and oxidation.

 

3. Polysaccharide Separation and Purification

After removing impurities, a mixed polysaccharide solution is obtained. The process of separating this solution into various single polysaccharides is known as purification. More common purification methods include precipitation, chromatography, zone electrophoresis, ultracentrifugation, and other biochemical analysis methods. Typically, polysaccharide purification requires combining two or more methods to optimize results.

 

Due to the diverse composition, complex structure, and large molecular weight of polysaccharides, analysis is typically conducted from the following four aspects:

1. Sugar Content Determination

The developer-sulfuric acid method is commonly used to determine sugar content in samples. Monosaccharides, polysaccharides, and their derivatives are hydrolyzed into monosaccharides under sulfuric acid action, quickly dehydrated to form aldehyde derivatives, and then condensed with phenol or aromatic amines to form colored compounds. The polysaccharide content is indirectly determined by colorimetric quantification. These methods are simple, fast, sensitive, and have good color stability for colored compounds.

 

2. Molecular Weight Determination

There is no absolute method for determining polysaccharide molecular weight, so statistical average is typically used. Previously, osmotic pressure, end group, viscosity, and light scattering methods were generally used, but they were complex and prone to causing error. Currently, gel filtration and high performance liquid chromatography (HPLC) are more commonly used. Both methods must use standard polysaccharides with known molecular weights as controls. For polysaccharides with molecular weights less than 50,000, mass spectrometry can be used.

 

3. Component Analysis

Polysaccharide component analysis methods are generally divided into traditional chemical analysis, physical analysis (instrumental analysis), and biological analysis. Chemical analysis includes partial or complete acid hydrolysis, neutralization, and filtration. Finally, paper chromatography (PC), thin-layer chromatography (TLC), gas chromatography (GC), HPLC, or ion chromatography (IC) are used for analysis. Widely used instrumental analysis methods include spectrophotometry, infrared spectroscopy (IR), nuclear magnetic resonance (NMR), GC, and MS.

 

4. Structural Identification

Polysaccharides have more complex macromolecular structures than proteins. The diversity of monosaccharides, linkage methods, and branch complexities make structural identification challenging. The main goal of structural identification is to analyze the molecular weight range, monosaccharide types, proportions, linkage sequences, and glycosidic bond configurations of polysaccharides. Common structural analysis methods include periodate oxidation, Smith degradation, and methylation reactions. In recent years, the use of advanced instruments has also significantly improved analytical methods.