Application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in preparation of chitosan oligosaccharides (COS) with degree of polymerization (DP) 5–12 containing well-distributed acetyl groups

Abstract

COS have many biological activities, and have been widely used as a health food. Molecular size is considered as a key parameter for COS’ activities. However, many criteria are used practically, and true qualities of COS from different producers may not be always comparable. This can partly explain the disagreement in COS’ functional researches, as resulting in COS, even with astonish effects, have not been further developed as a drug for tumor patients. As anti-tumor activities have been studied based on DP in pharmacological researches, we employed MALDI-TOF-MS to monitor fine structure, including DP, in COS’ preparation and comparison. Then one of the COS products was analyzed with the composition of DP 5–12, mainly 7–10. Moreover, that COS’ product contains well-distributed acetyl groups, while typical Commercial COS sample nearly contains no acetyl groups. As fresh precise parameters, the DP and the number of acetyl groups matching with special DP can be introduced in COS’ further study on structure–activity relationships (SARs) as a new drug.