The Preparation and Bioactivity Research of Agaro-Oligosaccharides
Hai-Min Chen1, Li Zheng2 and Xiao-Jun Yan1*
1Key Laboratory of Marine Biotechnology, Post Box 71, Ningbo University, Ningbo 315211, P. R. China
2Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, P. R. China
Article history:
Received June 4, 2004
Accepted November 22, 2004
Key words:
agaro-oligosaccharides, orthogonal matrix, HPLC, acid, degradation, antioxidant, α-glucosidase
Summary:
Agaro-oligosaccharides were hydrolytically obtained from agar using hydrochloric acid, citric acid, and cationic exchange resin (solid acid). The FT-IR and NMR data showed that the hydrolysate has the structure of agaro-oligomers. Orthogonal matrix method was applied to optimize the preparation conditions based on α-naphthylamine end-labeled HPLC analysis method. The optimal way for oligosaccharides with different degree of polymerization (DP) was achieved by using solid acid degradation, which could give high yield and avoid solution neutralization process. Agaro-oligosaccharides with high purity were consequently obtained by activated carbon column isolation. Furthermore, the antioxidant and α-glucosidase inhibitory activity of three fractions were also investigated. The result indicated that 8 % ethanol-eluted fraction showed highest activity against α-glucosidase with IC50 of 8.84 mg/mL, while 25 % ethanol-eluted fraction possessed excellent antioxidant ability.
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