Separation and scavenging superoxide radical activity of chitooligomers with degree of polymerization 6-16.

The separation of chitooligomers (COS) with well-defined degree of polymerization (DP) is of interest to further study their bioactivity. However, there has been no report on separation of chitooligomers with DP>6 and the activity of these oligomers is unknown. This paper focuses on separating COS with DP>6 and five fractions were separated from the prepared fully deacetylated chitooligomers mixture by CM Sepharose Fast Flow column and analyzed by HPLC, which mainly contained glucosamine oligomers with DP6-7 (41.31%, 50.22%), DP7-8 (22.47%, 70.13%), DP9-10 (53.06%, 27.99%), DP10-12 (18.45%, 49.36%, 22.31%), and DP>12, respectively. The superoxide radical scavenging activity of each fraction was investigated. The oligomers with DP ranging from 10 to 12 exhibited higher scavenging activity than other fractions and in combination with the DP distribution of fractions, it was further concluded that the chitooligomers with DP11 was likely to be optimal for scavenging superoxide radical activity.